To compare the analgesic efficacy of additional 0.1% bupivacaine to patient-controlled epidural analgesia (PCEA) using buprenorphine and droperidol after gynecological surgery.
Randomized, double-blinded study.
Operating theater and general ward at Jichi Medical School Hospital.
Thirty patients with American Society of Anesthesiologists physical status I and II scheduled for gynecological surgery.
Patients received combined general and epidural anesthesia for surgery and epidural analgesia for postoperative analgesia. Patients were assigned to receive PCEA with or without 0.1% bupivacaine. Group 1 (n = 15) received buprenorphine 20 microg and droperidol 0.1 mg diluted with saline, and group 2 (n = 15) received bupivacaine 2 mg, buprenorphine 20 microg, and droperidol 0.1 mg diluted with saline (0.1% bupivacaine solution) in a bolus dose of the PCEA, respectively. No background epidural infusion was used.
Visual analog pain scale (VAPS) scores at rest and on coughing, and cumulative frequency of self-administrated analgesic solution in PCEA were recorded at 24 and 48 hours postoperatively.
There were no significant differences noted between the groups in VAPS scores at rest or in cumulative volumes of PCEA solution in 24 or 48 hours postoperatively. Median VAPS scores on coughing in group 2 were significantly lower than those values in group 1 at 24 hours (36 vs 65 mm, P < .001) and 48 hours (32 vs 54 mm, P = .036) postoperatively.
Addition of 0.1% bupivacaine to PCEA using buprenorphine and droperidol provides better analgesia on coughing after gynecological surgery.
To assess the influence of ropivacaine concentration on wound instillation-induced postoperative analgesia following total abdominal hysterectomy with bilateral salpingo-oophorectomy.
Prospective, randomized, double-blind study.
Large referral hospital.
40 ASA physical status I and II patients undergoing total abdominal hysterectomy with bilateral salpingo-oophorectomy.
A standard general anesthetic was administered. In all cases surgery was performed via a Pfannenstiel incision. On completion of the surgery, a multi-orifice, 20-gauge epidural catheter was placed above the fascia such that the tip was sited at the point that demarcated 50% of the length of the surgical wound. Thereafter, the catheter was connected to an electronic patient-controlled analgesia (PCA) device programmed to deliver 9 mL of drug, with a lockout time of 60 minutes and no basal infusion. Patients were randomized to receive PCA with ropivacaine 0.1% (Group 0.1) or ropivacaine 0.2% (Group 0.2). During the first 6 postoperative hours, a co-investigator administered "rescue" morphine (2 mg IV). Thereafter, "rescue" meperidine 1 mg/kg was administered on patient request.
The number of attempts to activate the PCA device and actual PCA instillations during the 24 hour study period were similar between the groups. The number of 2 mg "rescue" morphine dosages administered was 4.3 +/- 1.7 versus 4.4 +/- 2.5 for the Group 0.1 and Group 0.2, respectively. For Group 0.1 and Group 0.2, the total dose of "rescue" morphine administered during the first 6 postoperative hours was 8.7 mg +/- 3.6 versus 9.1 mg +/- 5, respectively. "Rescue" meperidine administration during the subsequent 18 hours was similar between the groups. Throughout the study period, pain scores were similar between the groups.
With a pre-set volume, varying the concentration of ropivacaine (0.1% versus 0.2%) does not affect the analgesic efficacy of wound instillation following total abdominal hysterectomy with bilateral salpingo-oophorectomy.
To study the electrophysiologic and clinical effects of epidural morphine combined with either bupivacaine 0.125% or ropivacaine 0.2%.
Comparative, randomized, double-blind study.
Intensive care unit and hospital ward of a university hospital.
18 adult ASA physical status I and II patients with degenerative or idiopathic scoliosis, undergoing posterior spinal fusion with instrumentation.
Patients received epidural administration of 10-mL bolus of either bupivacaine or ropivacaine followed by a 6-mL/h infusion for 48 hours of unlabeled local anesthetic. In all patients, epidural morphine 5 mg was added daily.
Assessment was focused mainly on somatosensory cortical evoked potentials, soleus H-reflex, and F waves. These electrophysiologic data were recorded before and after epidural medications. Second, respiratory rate, Paco(2), visual analog score (VAS), and side effects such as postoperative nausea and vomiting (PONV), gastrointestinal (GI) transit delay, and urinary retention were noted.
Bupivacaine 0.125% + morphine was given to 9 patients, and ropivacaine 0.2% + morphine was given to 9 other patients. H-reflex, F waves, and somatosensory cortical evoked potential recording remained unchanged across the time of assessment. Respiratory rate and Paco(2) values were normal. VASs were indifferently low at rest, but they were lower with bupivacaine than with ropivacaine on mobilization. The frequency of PONV was indifferently high. No altered GI transit or urinary retention was noted.
After epidural administration during the study conditions, bupivacaine 0.125% and ropivacaine 0.2% combined with morphine allow for neurologic examination.
To establish the analgesic effective doses as defined as a visual analog pain scale (VAS) of at least 10 for 95% of parturients (ED95) receiving either epidural fentanyl or sufentanil with bupivacaine 0.125% for labor analgesia.
Double-blind, randomized controlled study.
Two tertiary-care teaching hospitals.
100 female patients, at full-term pregnancy, in active early labor (< 5 cm cervical dilation) and requesting obstetric anesthesia services for labor analgesia.
Patients were randomized and equally distributed to receive one of ten epidural dosing regimens of bupivacaine 0.125% alone or with either fentanyl 25, 50, 75, or 100 micrograms or sufentanil 5, 10, 15, 20, or 25 micrograms in a 10-ml bolus after a 3-ml test dose of bupivacaine 0.25%.
VAS scores were obtained from each parturient using a 10-cm plastic VAS slide rule at times 0, 1, 5, 10, 15, 20, 25, and 30 minutes, and then again when the patient requested additional analgesia. Analgesic duration and demographic and obstetric data also were obtained. Using a log-probit dose-response analysis, analgesic success as defined as a VAS of at least 10 with each opioid dose was plotted and an ED95 value of 8 micrograms and 50 micrograms was established for sufentanil and fentanyl, respectively, in bupivacaine 0.125%. No statistical difference was detected for analgesic duration or incidence of side effects between analgesic groups.
Epidural analgesia with fentanyl and sufentanil in bupivacaine 0.125% behaves in a dose-response fashion allowing for the determination of equipotent dose of each.
A 51-year-old ASA physical status II, non-insulin-dependent diabetic male patient manifested lower limb nerve injury after receiving postoperative epidural analgesia with ropivacaine 0.2%. The case is presented, including a discussion of the relation between local anesthetic toxicity and diabetic neuropathy.
To evaluate the effects of adding low concentration of fentanyl to 0.2% ropivacaine when providing patient-controlled epidural analgesia (PCEA) outside the Post-Anesthesia Care Unit.
Prospective, randomized, double-blind study.
Inpatients at a University Department of Anesthesia.
32 ASA physical status I, II, and III patients, who were scheduled for elective major abdominal surgery, including bowel resection, hepatic resection, and pancreaticoduodenectomy.
Patients received standard general/epidural anesthesia. After surgery patients were randomly allocated in a double-blind fashion to receive PCEA with either 0.2% ropivacaine (n = 16) or 0.2% ropivacaine/2 microg/mL fentanyl (n = 16) [background infusion ranging between 4 and 6 mL/hr, with 1.5-mL incremental doses and a 20-min lock-out time]. Dynamic pain during coughing, sedation, pulse oxymetry, hemodynamic variables, and motor block were evaluated at 1, 6, 12, 24, and 48 hours after the end of surgery by a blinded observer. Occurrence of untoward events, including nausea, vomiting, pruritus, need for supplemental oxygen (for SpO(2) < 90%), and respiratory complications, as well as total consumption of PCEA solution and incremental doses given to the patient were also recorded.
Measurements and main results:
No differences in pain relief, motor block, degree of sedation, recovery of gastrointestinal motility, and other side effects were observed between the two groups. Patients receiving 0.2% ropivacaine alone requested far more incremental doses (23 doses [0-60] vs. 5 doses [0-25]) (p = 0.006) and needed far more analgesic solution (230 mL [140-282] vs. 204 [130-228]) (p = 0.003) than patients receiving the ropivacaine/fentanyl mixture. Peripheral oxygen saturation was lower at 12, 24, and 48 hours during ropivacaine/fentanyl infusion than in patients receiving ropivacaine alone (12 h: 91% +/- 2% vs. 95% +/- 2%, p < 0.006; 24 h: 93% +/- 1% vs. 96% +/- 2%, p = 0.003; 48 h: 92% +/- 1.8% vs. 96% +/- 1%, p = 0.004).
A thoracic epidural infusion of 0.2% ropivacaine, with or without fentanyl, provided effective pain relief in most patients with a very low degree of motor blockade. Adding 2 microg/ml fentanyl to 0.2% ropivacaine reduced total consumption of local anesthetic solution and need for incremental doses, but did not provide clinically relevant advantages in quality of pain relief and incidence of motor block, leading to a significant decrease in peripheral SpO(2), lasting up to 48 hours after surgery.
To compare the effects of 0.2% epidural ropivacaine and those of 1% epidural ropivacaine on predicted propofol concentrations and bispectral index scores (BISs) at three clinical end points.
Randomized double-blind study.
Thirty-five (35) ASA physical status I and II patients scheduled for elective surgery of the lower abdomen.
Patients were randomly divided into 2 groups to receive epidurally 8 mL of 0.2% or 1% ropivacaine followed by the same solution at a rate of 6 mL/h.
Twenty minutes after starting ropivacaine, a target-controlled infusion of propofol was started to provide a predicted blood concentration of 3 microg/mL; it increased by 0.5 microg/mL every 60 seconds until all 3 clinical end points were reached, as follows: P1, when patients lost consciousness; P2, when patients failed to show pupillary dilation and skin vasomotor reflex to transcutaneous electric stimulation applied to the upper level of loss of cold sensation; and P3, when patients failed to show pupillary dilation and skin vasomotor reflex to transcutaneous electric stimulation applied to C5.
The effective concentration 50 values for both predicted blood and effect-site propofol concentrations were significantly larger in the 0.2% group than in the 1% group at all end points. The BIS at every end point was significantly smaller in the 0.2% group than in the 1% group.
During combined epidural-propofol anesthesia, unconsciousness and lack of response to noxious stimulation occurred at lower predicted concentrations with 1% epidural ropivacaine than with 0.2% epidural ropivacaine. The results also suggest that the BIS may not be a good indicator when propofol anesthesia is combined with epidural anesthesia.
To compare the anesthetic effects of two different concentrations and doses of ropivacaine (0.2% and 0.25%) with those of a conventional dose of lidocaine 0.5%.
Prospective, randomized, double-blinded, clinical investigation.
Large metropolitan university hospital.
66 adult ASA physical status I and II patients undergoing forearm and hand surgery.
Patients were randomly allocated to three groups to receive intravenous regional anesthesia (IVRA). Study groups were: ropivacaine 0.2% (Group I, n = 22), ropivacaine 0.25% (Group II, n = 22), and lidocaine 0.5% (Group III, n = 22).
Tourniquet tolerance times and regression of sensory analgesia were noted. Verbal numerical pain scores (VNS), cumulative analgesic consumption, and side effects were recorded during surgery and postanesthesia care unit (PACU). Time to first pain medication intake and number of patients receiving analgesics in the PACU were recorded.
Additional tolerance times for the distal tourniquet were significantly higher in the ropivacaine 0.25% group than the other two groups. Regression of sensory anesthesia was fastest in the lidocaine group. During the PACU stay, VNSs were significantly lower in the first 20 minutes in the ropivacaine groups than the lidocaine group. Time to first intake of pain medication in the PACU was soonest in the lidocaine group. The number of patients given analgesics in the PACU was highest in the lidocaine group. The number of patients taking > two tablets of tramadol was significantly lowest in the ropivacaine 0.25% group. No serious side effects were observed in any study group.
Longer tolerance times for the distal tourniquet, prolonged analgesia after tourniquet release, and lower analgesic requirements postoperatively make ropivacaine 0.2% and 0.25% an alternative to lidocaine for IVRA.
A case series of patients with diabetic nephropathy, who underwent lower limb debridement or amputation below the knee during successful combined sciatic and femoral nerve block with bupivacaine 0.25%, is presented. Because impaired nerve conduction in diabetes mellitus results in lower local anesthetic agent requirement, a dose-sparing, minimal effective concentration for surgical anesthesia for peripheral nerve blockade may be more favorable for patients with diabetes and chronic renal disease.
Part 1: To measure ropivacaine levels in the mother and infant at delivery after continuous lumbar epidural infusion. Part 2: To compare epidural ropivacaine to epidural bupivacaine for labor analgesia in regard to effectiveness, motor blockade, and maternal and neonatal effects.
Part 1: Open-labelled, non-blind study. Part 2: Randomized, double-blind study.
Labor and delivery units of two academic hospitals.
Part 1: 20 ASA physical status I and II parturients in active labor. Part 2: 81 ASA physical status I and II parturients in active labor.
For Part 1, 8 to 12 ml of 0.25% ropivacaine was administered through a lumbar epidural catheter to achieve a T10 dermatomal sensory level. An infusion of 0.25% ropivacaine, 8 to 10 ml/hr, maintained this sensory level. Maternal and umbilical cord blood samples obtained at delivery were analyzed for ropivacaine concentration. For Part 2, anesthetic management was similar to that previously described except patients were randomized to receive either 0.25% ropivacaine or 0.25% bupivacaine. Onset, regression, maximal spread of sensory block, and onset and degree of motor blockade were measured. Contraction pain as assessed using a visual analog scale (VAS), maternal blood pressure, and heart rate were determined every 5 minutes until a stable VAS-contraction score was achieved, and every 30 minutes thereafter. Neonatal assessment included Apgar scores and neurologic and adaptive capacity scores (NACS) at 15 minutes, 2 hours, and 24 hours.
For Part 1, the total and free maternal arterial concentrations of ropivacaine at delivery were 0.64 +/- 0.14 microgram/ml and 0.10 +/- .02 microgram/ml, respectively; the umbilical venous total and free concentrations were 0.19 +/- 0.03 microgram/ml and 0.12 +/- 0.07 microgram/ml, respectively (n = 12). The umbilical arterial and venous concentrations did not differ for both the free and total concentrations. For Part 2, there was no difference between ropivacaine and bupivacaine in the variables measured. Umbilical cord gases and Apgar scores were not different between the two groups; NACS were higher at 15 minutes and 2 hours in the ropivacaine group (p < 0.05) than the bupivacaine group.
Both ropivacaine and bupivacaine produced excellent analgesia for labor with no major adverse effect on the mother or neonate.
To investigate the effects of single-injection femoral nerve block (FNB) in postoperative pain after total knee replacement (TKR) and anterior cruciate ligament (ACL) reconstruction.
Prospective, randomized, double-blind study.
96 ASA physical status I, II, and III patients, scheduled for TKR or ACL reconstruction.
All patients received a standard spinal anesthetic, then were randomly divided into three treatment groups as follows: Group B (n = 30) received an FNB with 40 mL of 0.25% bupivacaine containing epinephrine, 1:200,000; Group R (n = 32) received an FNB with 40 mL of 0.25% ropivacaine; and Group C (n = 28) received no FNB.
The following clinical outcomes were assessed at up to 6 hours (T1), 6 to 10 hours (T2), and 10 to 24 hours (T3) after spinal anesthesia was given: visual analog scale (VAS) for pain, both at rest and on movement (no or mild pain, moderate pain, or severe pain); morphine use; sensory block in the femoral, obturator, and lateral femoral cutaneous nerve dermatomes; and motor block of the femoral and obturator nerves.
Except for VAS during rest and on movement at time T3, there were more Group C patients who experienced moderate or severe pain than those who had no pain or mild pain, when compared with Groups R and B. Sensory block in the femoral and lateral femoral cutaneous nerve dermatomes did not differ between Groups R and B at any times. However, sensory block in the obturator nerve dermatome was lower in Group R than Group B only at T3. We observed a lower, significant use of morphine at T2 when comparing Groups R and B with Group C. No Group R patient and about 30% of Group B patients remained with motor block of femoral and obturator nerves at T3. Except for frequency of nausea, which was highest in Group C, the frequency of other side effects was similar among the three groups.
Femoral nerve block using 0.25% ropivacaine or 0.25% bupivacaine is an effective method of postoperative analgesia after TKR and ACL reconstruction, particularly for the first 10 hours after spinal anesthesia.
To distinguish among potential predictors of early, easy intubation in children, including apnea, neuromuscular block at two sites, and time, after administration of 0.3 mg/kg of mivacurium.
Prospective, randomized study.
Operating rooms of Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania.
60 ASA physical status I and II children aged 2 through 7 years, scheduled for elective surgical procedures requiring endotracheal intubation.
After premedication with midazolam, general anesthesia was induced with halothane and nitrous oxide, and patients were randomly assigned to one of four groups. Mivacurium 0.3 mg/kg was given and tracheal intubation was begun 45 seconds after its injection, or when apnea, block of the orbicularis oculi, (OO) or block of the adductor pollicis (AP) was noted. Intubation conditions were evaluated by an experienced endoscopist.
The first clinical event after administration of mivacurium 0.3 mg/kg was apnea at 43 seconds (median) (average 48 seconds, SEM 2 seconds) after injection. The difference in the time at which neuromuscular block occurred at the AP (median 75 seconds) (average 77 seconds, SEM 2 seconds) and the OO (median 63 seconds) (average 68 seconds, SEM 4 seconds) was statistically, but not clinically, significantly different. All nine intubations that were begun at least 90 seconds after administration of mivacurium resulted in good or excellent intubation conditions, as did 30 of the 51 intubations started earlier.
In children, there is no advantage to monitoring neuromuscular function at the OO rather than the AP. After administration of 0.3 mg/kg of mivacurium, a 90-second interval before the start of intubation was a better predictor of good intubation conditions during halothane anesthesia (1% inspired) than were changes in evoked neuromuscular function.
We report on the case of a reappearance of a supraclavicular nerve block after the apparent initiation of its resolution in a 21-year-old athlete undergoing repair of a valgus impaction syndrome of his right elbow. The patient's anesthetic management consisted of a supraclavicular nerve block and general anesthesia. The patient was discharged home with an apparent resolving nerve block. He returned to the hospital urgently when, at 7 hours after blockade, he lost all motor-sensory function in his arm. His workup ultimately yielded negative results, and the block resolved at 23 hours. In addition to documenting an abnormal course of a supraclavicular block, this case report questions the appropriateness of placing long-acting nerve blocks in outpatients.
To compare the tolerance and efficacy of the new hydroxyethyl starch (HES) 130/0.4 with a current HES solution (HES 200/0.5) in patients undergoing preoperative autologous blood donation as a model of surgical blood loss. HES 130/0.4 is expected to be a plasma substitute as efficacious as current HES solutions while offering such advantages as more complete renal elimination and reduced tissue storage.
Controlled, randomized, double-blind, phase II clinical trial.
1500-bed university hospital.
60 ASA physical status II and III patients scheduled for elective cardiac and noncardiac surgery, and meeting selection criteria for autologous blood donors.
Collection of 500 mL of blood with simultaneous intravenous (IV) infusion of 500 mL of either HES 130/0.4 or HES 200/0.5 (mean molecular weight 130 kD and 200 kD, degree of substitution 0.4 and 0.5, respectively).
Noninvasive measurements of heart rate and arterial blood pressure were obtained every 5 minutes until 1 hour after blood donation and infusion of the study drugs; laboratory studies (complete blood counts, electrolytes, markers of renal and liver function) were performed; and follow-up assessment of adverse events was undertaken by questionnaire 24 hours after blood donation and infusion of the study drugs.
Both hemodynamics and laboratory test results did not differ significantly between the groups at any time. Hemodynamics remained stable in each group, and no adverse event was observed in any patient until one hour after blood donation and infusion of the study drugs. Adverse events elicited by postphlebotomy questionnaire were mild and probably unrelated to HES infusion.
Intravenous infusion of 500 mL of the new HES 130/0.4 was tolerated well and maintained cardiovascular stability in patients undergoing preoperative autologous blood donation. HES 130/0.4 proved equivalent to HES 200/0.5 in every measured respect. Its pharmacokinetic profile may render HES 130/0.4 an attractive alternative to current HES solutions.
To determine the maternal and fetal effects of the addition of epidural sufentanil to 0.5% bupivacaine for cesarean delivery.
Randomized, double-blind, prospective study.
University Hospitals, Katholieke Universiteit Leuven, Leuven, Belgium.
Sixty women at term scheduled for elective cesarean section, all of whom had elected epidural anesthesia.
The 60 women were divided into three groups of 20, with each group receiving a different 1 ml study solution: saline (control) or sufentanil 20 micrograms or sufentanil 30 micrograms added to 0.5% bupivacaine and epinephrine (1:200,000).
In the mother, the quality of anesthesia, the duration of postoperative analgesia, the volume of anesthetic, and the frequency of side effects were examined. The neonates were evaluated at 5 and 10 minutes after birth by Apgar scores and between 60 and 120 minutes after birth by both the screening test developed by Prechtl and the Neurological and Adaptive Capacity Scoring System. Immediately after delivery, maternal and umbilical vein blood were drawn and assayed for sufentanil levels. Adding sufentanil significantly improved the quality of anesthesia without depressing the neurobehavioral status of the baby.
The epidural injection of sufentanil added to 0.5% bupivacaine with epinephrine improved the quality of anesthesia during elective cesarean section without jeopardizing the safety of the baby.
To compare the influence of baricity and patient positioning during onset of subarachnoid block in patients placed in the prone, jackknife position with head-down tilt of 15 degrees .
Operating room of Tonami General Hospital.
180 ASA physical I and II patients (134 men and 46 women), aged 18 to 54 years, scheduled for elective perianal surgery.
Patients were randomly divided into 6 groups (n = 30 each) based on baricity (hyperbaric or isobaric) of 0.5% bupivacaine (5 mg) and duration of the sitting position (two, 5, or 10 min) after injection.
Sensory block levels were examined by pinprick at 0, 5, 10, 20, and 60 minutes after jackknife positioning. Systolic blood pressure and heart rate were also recorded.
After jackknife positioning, sensory block levels progressively increased until 15 or 20 minutes in all groups. Regardless of baricity of bupivacaine, sensory block levels were higher at 10 through 60 minutes in the two-minute sitting groups than in the 5-minute or 10-minute sitting groups (P < 0.01 and P < 0.01, respectively), and in the 5-minute sitting groups than in the 10-minute sitting groups (P < 0.05). The mean highest sensory block levels were T5, T9, and T11 in the two-minute, 5-minute, and 10-minute sitting groups, respectively.
Patient positioning, not baricity of bupivacaine, significantly affected the cephalad spread of spinal anesthesia, and a 10-minute period in the sitting position limits the maximum cephalad spread to T11.
This study tested the hypothesis that the addition of fentanyl 75 mcg to bupivacaine 0.5% at the onset of epidural anesthesia for cesarean section reduces the onset time for T4 sensory blockade. The study was conducted in a randomized, double-blind fashion. The same observer performed sensory testing using pain to pinprick. Fourteen ASA I patients scheduled for elective cesarean section had epidural catheters placed. Group 1 (n = 7) received bupivacaine 0.5%, and group 2 (n = 7) received bupivacaine 0.5% plus fentanyl 75 mcg. Patients 5'0'' to 5'4'' in height received 15 ml, and patients 5'5'' to 5'9'' received 20 ml of bupivacaine. There were no adverse effects on the neonate or clinically important changes in maternal hemodynamics. The maternal age, height, weight, and bupivacaine dose did not differ between groups (p greater than 0.05). For group 1, the mean times for sensory loss at T7, T6, T5, and T4 were 13.1 +/- 3.8 minutes, 15.0 +/- 4.0 minutes, 16.9 +/- 4.3 minutes, and 19.3 +/- 4.9 minutes, respectively; for group 2, the mean times were 8.1 +/- 0.9 minutes, 9.9 +/- 1.1 minutes, 11.3 +/- 1.5 minutes, and 12.7 +/- 2.0 minutes, respectively. Two-factor analysis of variance between groups 1 and 2 showed a significant difference (p less than 0.0001), representing a 35% reduction of mean onset time. The coefficient of variation of the mean onset times for group 1 subjects was 26.6% +/- 1.7% and for group 2 subjects 12.7% +/- 2.2% (p less than 0.001), representing a 50% reduction in between-subject variation.(ABSTRACT TRUNCATED AT 250 WORDS)
To evaluate the efficacy of three different concentrations of ropivacaine (0.5%, 0.75%, and 1%) together with a single concentration of hyaluronidase administered for peribulbar block.
Prospective, randomized, double-blind study.
Anesthesia department of a university teaching hospital.
68 ASA physical status I, II, and III patients undergoing elective cataract surgery.
Patients were randomly allocated to receive peribulbar block with 6.5 mL of either 0.5% (Group Ropi-5; n = 22), 0.75% (Group Ropi-7.5; n = 22), or 1% ropivacaine (Group Ropi-10; n = 24). In all patients, 0.5 mL of hyaluronidase was added to the local anesthetic solution.
A larger proportion of patients in Groups Ropi-7.5 (82%) and Ropi-10 (83%) showed complete motor block 15 minutes after injection compared with Group Ropi-5 (55%;p = 0.05, andp = 0.03, respectively). Hypotension (reduction of systolic blood pressure by 30% or more from baseline) was observed in two Group Ropi-5 patients (9%), and two Group Ropi-7.5 patients (9%;p = 0.31), whereas bradycardia (reduction in heart rate < or = 50 bpm) was observed in one Group Ropi-5 patient (4%), and three Group Ropi-10 patients (12%;p = 0.18). Seven hours after surgery, a smaller proportion of Group Ropi-10 patients (64%) showed complete recovery of sensory function as compared with both Group Ropi-5 (94%) and Group Ropi-7.5 (90%;p = 0.03 and p = 0.03, respectively). Complete recovery of motor function 1 hour after surgery was more frequent in Group Ropi-5 (37%) than in Group Ropi-7.5 (5%) or Group Ropi-10 (9%;p = 0.05 and p = 0.05, respectively); however, no other differences in recovery of motor function were observed at any other observation times, with complete recovery in all patients 7 hours after surgery.
While confirming that ropivacaine is a good option for peribulbar anesthesia, this study demonstrated that the use of 0.75% or 1% concentrations are preferred in that they produce quick and deep sensory and motor block of the operated eye. If recovery of normal motor function is important after surgery, the 0.75% concentration probably represents the best compromise.
To evaluate the pharmacokinetic profile of 0.35 mL/kg of 0.5% levobupivacaine during superficial and combined (deep and superficial) cervical plexus block (CPB) in patients undergoing minimally invasive parathyroidectomy.
Prospective randomized study.
Operating theater of a university hospital.
12 ASA physical status II and III patients (11 women and 1 man), scheduled for minimally invasive parathyroidectomy.
Seven and 5 patients were randomly assigned to receive either superficial or combined CPB, respectively. The superficial CPB was performed with an injection of 0.35 mL/kg of 0.5% levobupivacaine subcutaneously along the posterior border of the sternocleidomastoid muscle and deeper on its medial surface. The combined CPB was initiated by the deep block at the C3 level vertebra by injecting 0.2 mL/kg of 0.5% levobupivacaine, followed by the superficial block with an injection of the remaining 0.15 mL/kg. After completion of the block, venous blood was sampled at the intervals of 5, 10, 15, 20, 30, 45, and 60 minutes.
Venous plasma concentrations were measured using gas chromatography-mass spectroscopy. Mean +/- SD of maximal concentrations of levobupivacaine was 0.58 +/- 0.41 mg/L in group superficial and 0.52 +/- 0.28 mg/L in group combined (P = 0.71). The median (range) time required to reach the maximal concentrations was 30 minutes (20-30 min) in group superficial and 20 minutes (15-30 min) in group combined (P = 0.45). The areas under the drug concentration/time curve (AUC(10-60)) were also similar in both groups. No signs of central nervous system or cardiovascular toxicity or other untoward events were observed in any patient.
With the given dose regimen, levobupivacaine plasma concentrations were within safe ranges.
Upper extremity surgery is usually performed with an axillary block. There is a risk of pneumothorax and phrenic nerve block when interscalene or supraclavicular block are used in day case surgery, or in patients with chronic obstructive pulmonary disease. The infraclavicular block is a simple, reliable, and easy to learn method to block the brachial plexus. No clinically relevant respiratory effects have been reported with infraclavicular block. Nonetheless, we report a case of a chronic obstructive pulmonary disease patient who developed severe respiratory failure requiring tracheal intubation after an infraclavicular block.
To determine by thrombelastography assessed coagulation, the effects of progressive hemodilution with three intravascular volume expanders.
Prospective, controlled, whole blood, volumetric ex vivo hemodilution study.
University of Pennsylvania Medical Center Operating Rooms.
60 ASA physical status I and II patients; phlebotomy prior to administration of IV fluids or medications.
Analysis of whole blood clotting determined by six thrombelastographic channels for control and five volumetric hemodilutions (11%, 25%, 33%, 50%, and 75%) with 0.9% saline, 5% albumin, and 6% hydroxyethyl starch (n = 20 for each diluent group).
Thrombelastographic parameters R (minutes), angle alpha (degree), MA (mm), and lysis (%) were measured and compared to the sample control for each dilution of the same specimen. There was no significant difference between control groups in any thrombelastographic variable (R, angle alpha, MA, or lysis). No changes were seen in any variable from any diluent at 11% hemodilution. Seventy-five percent hemodilution caused significantly hypocoagulable changes from control for all thrombelastographic parameters for all three diluents. Thrombelastographic indices differed significantly from controls at intermediate hemodilutions. Both colloids caused decreases in measured angle alpha and MA at lower hemodilution than did 0.9% saline. Albumin 5% caused significant hypocoagulable changes from control values at lower hemodilution than did either 0.9% saline or 6% hydroxyethyl starch for all thrombelastographic parameters. Saline 0.9% increased angle alpha significantly at 50% hemodilution. Abnormal lysis did not occur at any dilution. Differing ex vivo effects of three different intravascular fluids thrombelastography assessed coagulation are found.
No differences were found after 11% hemodilution with any volume expanders. Hemodilution with up to 50% saline maintained thrombelastographic indices. Albumin produced early and profound hypocoagulable effects. Significant hypocoagulability occurred for all three diluents at 75% hemodilution. The study supports the use of albumin in patients at risk for thrombosis, and saline in patients with a need for normal hemostasis.
To determine the effects of intravenous (IV) 9-amino-1,2,3,4-tetrahydroacridine (THA) on postoperative somnolence in comparison to its pharmacokinetics.
Open-label study of the pharmacokinetics and effects of THA.
Postoperative intensive care ward at the Department of Neurosurgery, Uppsala University Hospital, Sweden.
Ten neurosurgical patients immediately after their operations were given 30 mg of THA for reversal of postoperative somnolence.
Plasma concentrations of THA and, in seven cases, the metabolite 1-hydroxy-THA were assayed using high-performance liquid chromatography. The pharmacokinetic data were compared to the degree of sedation and pain relief. After an IV dose of 30 mg THA, plasma concentrations were fit to an open two- or three-compartment model.
The antagonistic effect of THA on sedation occurred immediately following IV administration and lasted 60 to 90 minutes. At a mean plasma THA concentration of 44 +/- 18 ng/ml, patients were resedated. There was no obvious relation between analgesia and plasma THA concentrations. Side effects such as nausea, salivation, and lower heart rate (HR) were observed in several patients. Plasma clearance (C1) was high and showed a twofold inter-individual variation, with a mean of 2.64 +/- 1.17 L/h. Volume of distribution (Vd gamma) varied between 300 and 850 liters, with a mean of 477 +/- 185 liters. The plasma half-lives of rapid and slow distribution, and elimination were 2.1 +/- 0.7 minutes, 26 +/- 18 minutes, and 133 +/- 48 minutes, respectively. Maximum plasma concentrations of 1-hydroxy-THA were 27 to 90 ng/ml in five patients; the concentration was below 1 ng/ml in two other patients.
The duration of the effects of THA as an antagonist of postoperative sedation was only about double that seen previously after the IV administration of physostigmine in a similar group of patients, although the elimination half-life of THA was six times longer than that of physostigmine. A larger dose of THA possibly could have been given to prolong the period of antagonism of sedation, but the profile of adverse effects seen even at the doses used precluded that option.
To assess the most appropriate postoperative analgesic technique after hip surgery.
Prospective, nonrandomized study.
1,338 ASA physical status I, II, and III patients scheduled for elective unilateral total hip arthroplasty (THA).
During the first 48 postoperative hours, pain relief was provided by intravenous (i.v.) patient-controlled analgesia (PCA) with morphine (Group 1), continuous "3-in-1" block (Group 2), or patient-controlled epidural analgesia (PCEA) (Group 3).
During a 7.5-year period, pain scores, supplemental analgesia, satisfaction score, technical problems, and side effects were collected by our acute pain service. Postoperative pain relief was comparable in the three groups. More paracetamol was required in Group 2 (1.0 +/- 1.2 g/48 h) and Group 3 (0.9 +/- 1.3 g/48 h) than in Group 1 (0.5 +/- 1.1 g/48 h) (p < 0.01). However, only 8% of patients in Group 2 and 12% of patients in Group 3 needed an opioid. A higher incidence of technical problems was noted in Group 3 (23.4%) than in Group 1 (2.3%) or Group 2 (5.5%) (p < 0.001). A lower incidence of side effects was observed in Group 2 (23.5%) when compared with Group 1 (58.8%) and Group 3 (71.9%) (p < 0.001). Satisfaction score was significantly higher in Group 2 than in the other two groups [80 +/- 16 vs. 87 +/- 14 vs. 81 +/- 14 in Groups 1, 2, and 3 respectively (p = 0.003)].
After THA, i.v. PCA with morphine, continuous "3-in-1" block, and PCEA provided comparable pain relief. Because it induces the fewest technical problems and side effects, continuous "3-in-1" block is the preferred technique.
To challenge the view that the hyponatremia resulting from absorption of glycine 1.5% is attributed to the expansion of the extracellular fluid (ECF) volume, and that the change in serum sodium is therefore widely used to calculate the amount of irrigant absorbed.
Retrospective analysis of six studies.
Approximately 1.2 L of glycine 1.5% was infused in 23 volunteers (two studies), 1 L in 10 prostatectomy patients, 2.4 L in 6 sheep, 4 L in 6 other sheep, and 3 L in 9 piglets. The distribution of the irrigant water was estimated from the difference between the measured and the expected serum sodium levels, taking into account the urinary losses of sodium and water.
Between 30% and 50% of the irrigant volume had diffused into the cells 30 minutes after the infusion, and only between 0% and 50% of the fluid remained in the ECF. One hour later, natriuresis accounted for 100% of the residual hyponatremia in the small-volume experiments, and it accounted for approximately 50% in the large-volume experiments. The change in serum sodium could not be used to quantify the small infusion volumes, but the large ones could be quantified fairly accurately if assessed at the very end of the infusion.
Diffusion of water into the cells and natriuresis reduced and prolonged the hyponatremia associated with infusions of glycine 1.5%. This finding makes IV fluid with sodium added a more rational alternative than furosemide in the treatment of fluid overload with this irrigating solution.
To evaluate the effect of physostigmine on 1.5% sevoflurane anesthesia and recovery.
Prospective, randomized, double-blinded study.
Operating room of a university-affiliated, metropolitan hospital (Aretaieion Hospital and St Savas Hospital).
Forty female American Society of Anesthesiologists physical status I and II patients scheduled for breast biopsy.
Patients were randomly assigned in physostigmine (PHYSO) and normal-saline (NS) group. Anesthesia was induced with sevoflurane 8% using a vital capacity breath technique, and rocuronium 0.6 mg/kg was given to facilitate Laryngeal Mask Airway (LMA) No. 4 insertion. Anesthesia was maintained with end-tidal sevoflurane 1.5 minimum alveolar concentration (MAC; 3% end-tidal concentration) throughout the procedure.
After skin closure and under steady-state sevoflurane anesthesia 1.5 MAC, heart rate, blood pressure, and Bispectral Index (BIS) were recorded. Immediately after, the PHYSO group received intravenous 2 mg of physostigmine, whereas the NS group received equal volume of normal saline. Bispectral Index and hemodynamic measurements were recorded 5, 8, and 10 minutes after treatment. Anesthesia was then discontinued and the LMA was removed. Zero, 15, and 30 minutes after LMA removal, patients were evaluated for orientation, sedation, sitting ability, and the "picking up matches" test, as well as for nausea and vomiting.
No difference was found in BIS (29 +/- 4, 32 +/- 6, 31 +/- 6, 30 +/- 7, 84 +/- 11 in the PHYSO group vs 29 +/- 6, 30 +/- 6, 30 +/- 5, 31 +/- 5, 86 +/- 7 in the NS group), hemodynamic parameters, or recovery parameters between the 2 groups at any time. No nausea or vomiting was observed in either group.
Physostigmine did not influence BIS values or early recovery when administered to patients anesthetized with 1.5 MAC sevoflurane anesthesia.
Terminal deletions of chromosome 10q are uncommon. The resulting syndrome includes cardiac and facial anomalies, urogenital abnormalities, limb defects, and mental retardation. Most affected infants require surgical correction of these anomalies. Presented are features inherent in the syndrome that will aid the anesthesiologist in the perioperative management of such patients.
The purpose of the study was to determine whether epidural analgesia is unsafe for trial of labor (TOL).
Retrospective chart review.
Inpatient obstetric department at a university medical center.
One hundred ten ASA physical status I and II term parturients who attempted a TOL between December 1987 and June 1988.
All the parturients previously had low transverse uterine incisions and received continuous electronic fetal and uterine pressure monitoring throughout labor. All the parturients were offered epidural analgesia during labor with bupivacaine 0.25%.
Sixty-seven percent of the parturients had successful vaginal delivery. Fifty-one of the 110 parturients had epidural analgesia for labor. There were two complete uterine ruptures; neither had epidural catheters. Both of the complete ruptures presented with monitored fetal distress rather than abdominal pain. Both mothers and their infants recovered uneventfully.
Uterine rupture presents as monitored fetal distress rather than abdominal pain. Thus, epidural analgesia can be used in patients attempting a TOL.
To evaluate the incidence of perioperative minor adverse events and to analyze patient satisfaction based on potential explanatory variables.
Structured, face-to-face interview of 25% of all patients undergoing surgery during the period from January 2003 through June 2006.
Academic university medical center.
12,276 patients (5,793 men and 6,483 women) from all surgical disciplines: 7,440 patients had general anesthesia, 4,236 patients had regional anesthesia, and 600 patients had a combined general-regional anesthetic technique.
Occurrence of perioperative minor adverse events was assessed during the interview. Patient satisfaction was measured with a 4-point Likert scale.
3,652 (30%) patients reported at least one perioperative complaint and 737 (6%) patients reported multiple minor adverse events. Overall, a total of 4,475 minor adverse events were reported. Leading adverse events included postoperative nausea and vomiting (1,705 complaints), sore throat (1,228 complaints), and hoarseness (802 complaints). Patient satisfaction with anesthetic care was generally high (97% satisfied or highly satisfied). Patients were significantly more satisfied following regional than general anesthesia (P < 0.001). Patient dissatisfaction was also associated with the occurrence of at least one minor adverse event (P < 0.001) or with increasing ASA physical status (P < 0.001).
Minor events occur with a surprisingly high incidence and are significantly associated with patient dissatisfaction. Regional anesthesia is associated with fewer patient complaints and significantly higher postoperative patient satisfaction.
To provide a review of evaluation, feedback, and remediation methods in United States residency programs during 1995 to 1996. The information gathered is to serve as a framework for discussions within and among programs regarding ways to enhance their current processes of evaluation, feedback, and remediation, and to serve as a baseline for future assessments.
A three-page survey was mailed to program directors of each of the 145 anesthesiology programs listed in the Accreditation Council for Graduate Medical Education (ACGME/NRMP) Directory.
Quantitative and qualitative responses were sought about the resident evaluation process (including techniques of gathering information, frequency of evaluations, faculty compliance, and modes of offering feedback), departmental clinical competence committee, probation and remediation policies for problem residents, and the use of formal examinations. There was an 85.5% response rate. Frequency of evaluation of residents ranged from daily to quarterly: evaluations used both narrative comments and rating scales in 89% of institutions. Faculty compliance in the evaluation process was greater than 75% in 45.1% of programs. Only 25 (20.2%) programs offered formal training about resident evaluation to their faculty. Clinical competence committee meetings averaged five times annually. Ninety-five percent of committees were chaired by someone other than the department chairperson and 27% had resident members. A written policy regarding problem residents was used by 67.7% of programs, a formal probation policy by 82.2%. Standardized tests to provide feedback and guidance to residents existed in 48.3% of programs.
There is a tremendous variety of techniques and methodologies employed among anesthesiology residency programs with regard to evaluation, feedback, and remediation, within the framework of the ACGME guidelines. Faculty training in the assessment of and feedback to residents is one area in which many programs can begin to strengthen their current procedures.
To evaluate the effectiveness of the CTrach Laryngeal Mask Airway (LMA) when used electively.
Operating room of an academic hospital.
Data from 126 patients who were electively intubated with the CTrach LMA over a 16-month period were reviewed. Each patient's weight, height, ASA physical status classification, Mallampati score, thyromental distance, and cervical spine range of motion were recorded.
Successful ventilation was achieved in 100% of patients, while successful intubation was achieved in 89.7% of patients. The most common reason for failure to intubate was poor airway visualization and the inability to appropriately position the device anterior to the vocal cords.
The major advantage of the CTrach LMA is that it is the only device that allows airway visualization during patient ventilation; however, it does not have 100% success with intubation.
To investigate whether patients with postural orthostatic tachycardia syndrome (POTS) developed unexpected perioperative complications.
Retrospective case series.
Academic medical center.
The records of 13 patients with POTS, who underwent surgical procedures during general anesthesia, were studied. Details of disease management, anesthetic induction, hemodynamic response to induction and intubation, intraoperative course, and immediate postoperative management were analyzed.
Three patients developed prolonged intraoperative hypotension, which was not associated with induction of anesthesia. All 13 patients were successfully treated and they recovered without complications. There were no unplanned hospital or intensive care admissions.
Intraoperative hypotension, but not tachycardia, was observed in three of 13 patients with POTS who received general anesthesia for a variety of surgical procedures using multiple medications and techniques.
Pain is one of the main postoperative adverse outcomes. Single analgesics, either opioid or nonsteroidal antiinflammatory drugs (NSAIDs), are not able to provide effective pain relief without side effects such as nausea, vomiting, sedation, or bleeding. A majority of double or single-blind studies investigating the use of NSAIDs and opioid analgesics with or without local anesthetic infiltration showed that patients experience lower pain scores, need fewer analgesics, and have a prolonged time to requiring analgesics after surgery. This review focuses on multimodal analgesia, which is currently recommended for effective postoperative pain control.
To determine cost-effectiveness, we need to determine the value obtained for the price paid. Several points emerge. We need to identify specific recovery goals as our benefits, looking at early, intermediate, and late phases of recovery. Benefits such as effects on nausea may be specific to the procedure, duration, and site of practice. Time savings in the OR or recovery areas do not generate cost savings unless utilization actually increases or staffing actually decreases. Recovery care protocols that mandate a specific duration of stay in the PACU can negate any intraoperative or postoperative benefit differences generated by an anesthetic agent. Most of all, it is difficult to assign a dollar value to a very important benefit: patient satisfaction. Each of us, in our practices, must identify cost-effective choices for ambulatory anesthesia. Determining prices is simple. This we can and should do. Determining value, however, is more complicated and it is in this direction our work must lie.
We report the case of a 13 year old patient who received 3.0 mg of remifentanil during a 50-minute surgical procedure as a result of a dosage miscalculation. The patient failed to awaken at the conclusion of the procedure and showed signs of opioid overdose. She recovered spontaneously two hours later.
To characterize the clinical features that predispose to sinus bradycardia and cardiac arrest during spinal and epidural anesthesia.
Retrospective clinical review.
University affiliated medical center.
13 patients, aged 26 to 76 years, who suffered severe sinus bradycardia or asystole over a 5-year period, during which approximately 4,000 regional anesthetics were administered.
Case histories of 13 patients who developed severe sinus bradycardia or asystole during spinal or epidural anesthesia are summarized. Twelve cases occurred during spinal anesthesia, and the thirteenth, during epidural anesthesia. In all but one case, the acute event occurred 15 minutes or longer from the time of the anesthetic injection. Resuscitation was successful in all cases, with no postoperative sequelae.
The clinical picture suggests a reflex cause, possibly associated with low right-sided cardiac filling pressure. No common precipitating cause or high-risk patient profile was noted.
The perioperative use of neuraxial techniques in the presence of anticoagulation is a controversial issue. There are significant pharmacokinetic differences between anticoagulants that will affect the timing of neuraxial needle insertion or catheter removal. The pharmacologic profiles of commonly used anticoagulants in the perioperative period are reviewed. Studies examining the use of neuraxial techniques in the presence of various anticoagulants are reviewed and evaluated in the context of the American Society of Regional Anesthesia consensus statements.
To investigate whether oral omeprazole 20 mg decreases the risk of aspiration pneumonia in patients with gastric tube reconstruction.
Operation room of cancer center.
Thirteen patients with gastric tube reconstruction for esophageal cancer.
Oral omeprazole 20 mg was given the night before surgery. A rapid-sequence induction with cricoid pressure was employed for induction of anesthesia. After tracheal intubation, a nasogastric catheter was inserted into the gastric tube and the contents were aspirated.
The pH and volume of the gastric contents were measured. The pH and volume of the gastric tube contents were 4.5 +/- 1.6 (range from 2.5 to 7.0) and 9.5 +/- 10.2 mL (range from 0 to 30 mL), respectively. Food residue was recognized in nine patients. There was no patient with a pH below 2.5 and a volume of 25 mL or greater.
Omeprazole 20 mg decreased the acidity and volume of the gastric tube contents and reduced the risk of aspiration pneumonia in patients with a gastric tube in place.
To investigate the effects of ketamine and propofol on the cerebrovascular response to carbon dioxide (CO(2)) in humans during isoflurane anesthesia.
Randomized clinical investigation.Settings: University hospital of a medical school.
30 ASA physical status I and II adult, elective surgical patients. Interventions and Measurements: With each patient given air/oxygen/isoflurane anesthesia, the flow velocity in the middle cerebral artery (Vmca) and pulsatility index were measured using the transcranial Doppler method under hypocapnic [arterial CO(2)tension (PaCO(2)) 28-32 mmHg], normocapnic (PaCO(2) 38-42 mmHg), and hypercapnic conditions (PaCO(2) 48-52 mmHg). PaCO(2) was altered by supplementing the inspired gas with CO(2) without changing the respiratory conditions. Patients were then randomly assigned to receive either ketamine 1 mg. kg(-1) or propofol (2 mg. kg(-1)followed by an infusion of 6-10 mg. kg(-1). hr(-1)) (n = 15 for each drug), and the measurements were repeated.
Ketamine reduced both absolute and relative cerebrovascular reactivity to CO(2) significantly [2.9 +/- 0.8 (control) vs. 2.6 +/- 1.0 (ketamine) cm. sec(-1). mmHg(-1): p < 0.05; and 3.5 +/- 0.7 (control) vs. 2.8 +/- 0.9 (ketamine) %. mmHg(-1): p < 0.01, respectively]. However, ketamine did not reduce Vmca during hypercapnic conditions (117 +/- 29 cm. sec(-1)) compared with controls (120 +/- 28 cm. sec(-1)). Although propofol decreased Vmca during all conditions, it did not cause any change in either absolute or relative CO(2) reactivity [2.5 +/- 0.8 (control) vs. 2.5 +/- 1.0 (propofol) cm. sec(-1). mmHg(-1), and 3.3 +/- 1.3 (control) vs. 4.1 +/- 1.0 (propofol) %. mmHg(-1), respectively].
In humans given isoflurane anesthesia, a) ketamine reduced cerebrovascular response to CO(2), but cerebral blood flow (CBF) during hypercapnic conditions was comparable with controls, and b) although propofol decreases CBF, it maintains the cerebrovascular response to CO(2).
We encountered two patients who could be neither ventilated nor intubated after induction of anesthesia. In both cases, transtracheal ventilation failed after emergent cricothyroid membrane puncture with a 14-gauge intravenous (i.v.) catheter. In the first case, two catheters placed in rapid succession kinked, preventing gas exchange. In the second case, absence of a plunger on the needle-over-catheter assembly prevented confirmation of intratracheal placement. Both patients required emergent tracheal access by the surgeon. We suggest that transtracheal ventilation via standard i.v. catheters as a primary emergent rescue technique be reassessed.
To determine the frequency, outcomes, and risk factors for dental injury related to anesthesia.
Tertiary-care university hospital.
Patients who had a perianesthetic dental injury between August of 1989 and December 31, 2003.
A 1:2 case control study was done to identify the frequency, outcomes, and risk factors for dental injury. Perianesthetic dental injuries were defined as any notable change to the patient's dentition during the perianesthetic period that may or may not have required dental consultation or treatment.
Seventy-eight patients with perianesthetic dental injury were identified. The incidence of dental injury was one per 2,073 anesthetics. Eighty-six percent of dental injuries were discovered by the anesthesia provider. Maxillary incisors were the most frequently injured teeth. The most commonly reported injuries were enamel fracture, loosened or subluxated teeth, tooth avulsion, and crown or root fracture. Patients with poor dentition or reconstructive work, whose tracheas were moderately difficult or difficult to intubate, were at much higher risk (approximately 20-fold) of dental injury than those with good dentition and found to be easy to intubate. Among those whose tracheas were easy to intubate, patients with poor dentition or reconstructive work were 3.4 times more likely to have dental injuries related to anesthesia.
Dental injury is one of the most common adverse events reported in association with anesthesia. Risk factors include preexisting poor dentition or reconstructive work and moderately difficult to difficult intubation.
To examine the validity of our methods of anesthesia, i.e., awake intubation and assisted manual ventilation, in coping with the anesthetic problems particular to oral and maxillofacial surgery (OMF surgery).
Operating room and ward of a dental teaching hospital.
14,195 patients undergoing OMF surgery during the period from January 1971 to March 2000.
The kinds of anesthetic difficulties centering around airway problems and their frequency in OMF surgery were determined. In 2,401 patients (16.9%), awake intubation was employed because of definite or possible airway problems. No untoward effects due to awake intubation were noted. Volatile anesthetics were used with nitrous oxide (N2O) in 13,959 patients (98.3%), and their spontaneous respiration were assisted manually for the purpose of early detection of airway troubles such as accidental extubation, dislocation, kinking, and/or damage to the endotracheal tubes. Few accidents or complications were noted in relation to airway issues, and neither cardiac arrest nor death was experienced in these 14,195 patients.
Based on a sufficient number of anesthetic applications, awake intubation and assisted manual ventilation were proved to be useful in coping with the anesthetic difficulties particular to OMF surgery.
To assess the hemodynamic impact of dexmedetomidine administration in a large cohort of patients undergoing routine noncardiac surgery.
Retrospective database analysis.
Major academic medical center.
A valid electronic preoperative history and physical record and electronic perioperative anesthesia record of all adults undergoing noncardiothoracic procedures of > 60 minutes duration between January 2007 and September 2008 were reviewed. The primary composite endpoint was systolic blood pressure < 80 mmHg for > 5 minutes, heart rate < 40 bpm for > 5 minutes, or administration of vasoconstrictors (> 500 μg of phenylephrine by bolus or infusion or any epinephrine) or atropine intraoperatively.
A total of 15,656 cases, of whom 2,688 (17%) received dexmedetomidine preoperatively or intraoperatively and 12,968 (83%) did not receive dexmedetomidine, was identified. A significantly higher percentage of patients in the dexmedetomidine group met the composite endpoint criteria (27% vs 19%, P < 0.0001). However, there was no significant difference in the overall incidence of intraoperative hypotension (5.3% dexmedetomidine, 6% no dexmedetomidine) or bradycardia (0.4% in both groups). Dexmedetomidine patients received more phenylephrine or atropine (23% vs 15%, P < 0.0001).
In a large cohort of routine clinical practice cases, dexmedetomidine administration was not associated with more hypotension or bradycardia.
To evaluate the effects of adding 50 microg clonidine to 150 mg ropivacaine for superficial cervical plexus block in patients undergoing elective carotid endarterectomy (TEA).
Randomized, double-blind study.
Departments of Anesthesia and Vascular Surgery of a university hospital.
40 ASA physical status II and III patients undergoing elective TEA during superficial cervical plexus block.
Superficial cervical plexus block was placed using 20 mL of 0.75% ropivacaine alone (Ropi group, n = 20) or with the addition of 50 microg clonidine (Ropi-Clonidine group, n = 20). If required, analgesic supplementation was given with local infiltration with 1% lidocaine and intravenous fentanyl (50-microg boluses). Nerve block profile, need for intraoperative analgesic supplementation, and time to first analgesic request were recorded.
Median (range) onset time was 10 minutes (5-25 min) in the Ropi group and 5 minutes (5-20 min) in the Ropi-Clonidine group (P < 0.05). Intraoperative consumption of both 1% lidocaine and fentanyl was higher in patients of the Ropi group (15 mL [0-25 mL] and 250 microg [50-300 microg]) than in patients of the Ropi-Clonidine group (8 mL [0-20 mL] and 0 microg [0-150 microg]; P < 0.05 and P < 0.05, respectively). First postoperative analgesic request occurred after 17 hours (10-24 hrs) in the Ropi group and 20 hours (10-24 hrs) in the Ropi-Clonidine group (P > 0.05).
Adding 50 microg clonidine to 150 mg ropivacaine for superficial cervical plexus block shortened the onset time and improved the quality of surgical anesthesia in patients undergoing elective TEA.
To determine if the majority of reintubations, a potentially preventable adverse event, were predominantly due to residual muscle relaxant effects, we analyzed our quality assurance database to identify the causes of reintubation.
University of Michigan Department of Anesthesiology Quality Assurance (QA) database.
We analyzed QA records from 152,939 anesthetic cases performed from 1994 to 1999 at our institution. Of these cases, 107,317 were performed with a general anesthetic. The medical record of each patient requiring reintubation was obtained and reviewed to determine the cause of the reintubation.
A total of 191 reintubation events were identified. One hundred twelve of the 191 (59%) reintubations were due to respiratory problems; 11 of the 191 (6%) reintubations were due to complications of neuromuscular blocking drug use. Other causes were unintentional extubation, surgical complication, endotracheal tube problems, and cardiac problems. One hundred five reintubations (105/191, 55%) occurred in the operating room and 86 (86/191, 45%) occurred in the postanesthesia care unit.
Respiratory complications were the most common cause of reintubation in the perioperative period. Complications related to the neuromuscular blocking drugs were the fourth most common cause of reintubation. More reintubations occurred in the operating room than the postanesthesia care unit. Muscle relaxant effect and opioid effect are rare causes of respiratory failure in the anesthetized patient in the immediate postoperative period.
To describe the frequency and timing of intravenous patient-controlled analgesia (IV-PCA) or neuraxial morphine-induced postoperative respiratory depression.
Audit of data captured by routine quality assurance of the acute pain protocols that were implemented by nurses performing routine postoperative care.
The surgical wards of a university-affiliated, 700-bed, tertiary hospital.
In real time, the data of all patients enrolled into our Acute Pain Service (APS) were entered and stored in the APS database. Thereafter, patients who had received IV morphine via a PCA device or neuraxial morphine between January 1999 and December 2002 were isolated. From this subset, all patients in whom a respiratory rate (RR) less than 10 breaths per minute was recorded were retrieved.
From a total of 4500 patients, IV or neuraxial morphine was administered to 1524 patients. Eighteen (1.2%) cases of an RR less than 10 breaths per minute were recorded (13 patients, 4 patients, and 1 patient in the IV-PCA, daily epidural morphine, and single-dose intrathecal morphine groups, respectively). A direct correlation between intraoperative fentanyl administration and postoperative respiratory depression was demonstrated between the IV-PCA (P = 0.03) and epidural groups (P = 0.05). The time from IV-PCA initiation or last neuraxial morphine administration until the diagnosis of respiratory depression ranged between 2 hours and 31.26 hours and 2 hours and 12.15 hours, respectively. Ten (55.6%) patients received naloxone.
Morphine-induced respiratory depression may occur at any time during the APS admission. However, the optimal frequency of intermittent RR monitoring is unknown. Furthermore, because multiple variables (age, sex, prior opioid administration, site of operation) may affect morphine-induced respiratory depression, further investigation must be performed to determine the ideal monitoring protocol.