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Anesthesiology 06/2012; 116(6):1396-7. · 5.36 Impact Factor
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ABSTRACT: Background: The subjective experience of residual neuromuscular blockade after emergence from anesthesia has not been examined systematically during postanesthesia care unit (PACU) stays. The authors hypothesized that acceleromyography monitoring would diminish unpleasant symptoms of residual paresis during recovery from anesthesia by reducing the percentage of patients with train-of-four ratios less than 0.9.
Anesthesiology 10/2011; 115(5):946–954. · 5.36 Impact Factor
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ABSTRACT: The subjective experience of residual neuromuscular blockade after emergence from anesthesia has not been examined systematically during postanesthesia care unit (PACU) stays. The authors hypothesized that acceleromyography monitoring would diminish unpleasant symptoms of residual paresis during recovery from anesthesia by reducing the percentage of patients with train-of-four ratios less than 0.9.
One hundred fifty-five patients were randomized to receive intraoperative acceleromyography monitoring (acceleromyography group) or conventional qualitative train-of-four monitoring (control group). Neuromuscular management was standardized, and extubation was performed when defined criteria were achieved. Immediately upon a patient's arrival to the PACU, the patient's train-of-four ratios were measured using acceleromyography, and a standardized examination was used to assess 16 symptoms and 11 signs of residual paresis. This examination was repeated 20, 40, and 60 min after PACU admission.
The incidence of residual blockade (train-of-four ratios less than 0.9) was reduced in the acceleromyography group (14.5% vs. 50.0% control group, with the 99% confidence interval for this 35.5% difference being 16.4-52.6%, P < 0.0001). Generalized linear models revealed the acceleromyography group had less overall weakness (graded on a 0-10 scale) and fewer symptoms of muscle weakness across all time points (P < 0.0001 for both analyses), but the number of signs of muscle weakness was small from the time of arrival in the PACU and did not differ between the groups at any time.
Acceleromyography monitoring reduces the incidence of residual blockade and associated unpleasant symptoms of muscle weakness in the PACU and improves the overall quality of recovery.
Anesthesiology 09/2011; 115(5):946-54. · 5.36 Impact Factor
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ABSTRACT: Patients undergoing shoulder surgery in the beach chair position (BCP) may be at risk for adverse neurologic events due to cerebral ischemia. In this investigation, we sought to determine the incidence of cerebral desaturation events (CDEs) during shoulder arthroscopy in the BCP or lateral decubitus position (LDP).
Data were collected on 124 patients undergoing elective shoulder arthroscopy in the BCP (61 subjects) or LDP (63 subjects). Anesthetic management was standardized in all patients. Regional cerebral tissue oxygen saturation (Scto(2)) was quantified using near-infrared spectroscopy. Baseline heart rate, mean arterial blood pressure, arterial oxygen saturation, and Scto(2) were measured before patient positioning and then every 3 minutes for the duration of the surgical procedure. Scto(2) values below a critical threshold (> or = 20% decrease from baseline or absolute value < or = 55% for >15 seconds) were defined as a CDE and treated using a predetermined protocol. The number of CDEs and types of intervention used to treat low Scto(2) values were recorded. The association between intraoperative CDEs and impaired postoperative recovery was also assessed.
Anesthetic management was similar in the BCP and LDP groups, with the exception of more interscalene blocks in the LDP group. Intraoperative hemodynamic variables did not differ between groups. Scto(2) values were lower in the BCP group throughout the intraoperative period (P < 0.0001). The incidence of CDEs was higher in the BCP group (80.3% vs 0% LDP group), as was the median number of CDEs per subject (4, range 0-38 vs 0, range 0-0 LDP group, all P < 0.0001). Among all study patients without interscalene blocks, a higher incidence of nausea (50.0% vs 6.7%, P = 0.0001) and vomiting (27.3% vs 3.3%, P = 0.011) was observed in subjects with intraoperative CDEs compared with subjects without CDEs.
Shoulder surgery in the BCP is associated with significant reductions in cerebral oxygenation compared with values obtained in the LDP.
Anesthesia and analgesia 08/2010; 111(2):496-505. · 3.08 Impact Factor
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ABSTRACT: Experimental and clinical data suggest that morphine possesses unique cardioprotective and antiinflammatory properties. In this clinical investigation, we sought to determine whether the choice of intraoperative opioid (morphine or fentanyl) influences early recovery after cardiac surgery.
Ninety patients undergoing cardiac surgery with cardiopulmonary bypass were randomized to receive either morphine (40 mg) or fentanyl (600 mug) as part of a standardized opioid-isoflurane anesthetic. Quality of recovery was assessed using the QoR-40 questionnaire administered preoperatively and daily on postoperative days 1-3. During the first three postoperative days, pain was measured using a 100-mm visual analog scale, and the use of IV and oral pain medications (morphine or acetaminophen/hydrocodone) was quantified. Hemodynamic variables, duration of tracheal intubation, postoperative febrile reactions, organ morbidities, and intensive care unit (ICU) and hospital length of stay were evaluated.
Compared with patients given fentanyl, those receiving morphine had higher global QoR-40 scores on postoperative days 1 (173 vs 160, P < 0.0001), 2 (174 vs 164, P < 0.0001), and 3 (177 vs 167, P < 0.001). Differences between the groups were observed in the QoR-40 dimensions of emotional state, physical comfort, and pain (all P < 0.01-0.0001). Postoperative visual analog scale pain scores, use of pain medication in the ICU and surgical ward, and postoperative febrile reactions were reduced significantly in the morphine group (all P < 0.01). No differences between the groups were noted in duration of tracheal intubation, ICU and hospital length of stay, or postoperative complications.
In patients undergoing elective cardiac surgery with cardiopulmonary bypass, postoperative quality-of-life measures and pain control during recovery were enhanced when morphine (40 mg) was administered intraoperatively as part of a balanced anesthetic technique compared with fentanyl.
Anesthesia and analgesia 08/2009; 109(2):311-9. · 3.08 Impact Factor
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ABSTRACT: Incomplete recovery from neuromuscular blockade in the postanesthesia care unit (PACU) may contribute to adverse postoperative respiratory events. This study determined the incidence and degree of residual neuromuscular blockade in patients randomized to conventional qualitative train-of-four (TOF) monitoring or quantitative acceleromyographic monitoring. The incidence of adverse respiratory events in the PACU was also evaluated.
One hundred eighty-five patients were randomized to intraoperative acceleromyographic monitoring (acceleromyography group) or qualitative TOF monitoring (TOF group). Anesthetic management was standardized. TOF patients were extubated when standard criteria were met and no fade was observed during TOF stimulation. Acceleromyography patients had a TOF ratio of greater than 0.80 as an additional extubation criterion. Upon arrival in the PACU, TOF ratios of both groups were measured with acceleromyography. Adverse respiratory events during transport to the PACU and during the first 30 min of PACU admission were also recorded.
A lower frequency of residual neuromuscular blockade in the PACU (TOF ratio < or = 0.9) was observed in the acceleromyography group (4.5%) compared with the conventional TOF group (30.0%; P < 0.0001). During transport to the PACU, fewer acceleromyography patients developed arterial oxygen saturation values, measured by pulse oximetry, of less than 90% (0%) or airway obstruction (0%) compared with TOF patients (21.1% and 11.1%, respectively; P < 0.002). The incidence, severity, and duration of hypoxemic events during the first 30 min of PACU admission were less in the acceleromyography group (all P < 0.0001).
Incomplete neuromuscular recovery can be minimized with acceleromyographic monitoring. The risk of adverse respiratory events during early recovery from anesthesia can be reduced by intraoperative acceleromyography use.
Anesthesiology 10/2008; 109(3):389-98. · 5.36 Impact Factor
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Journal of cardiothoracic and vascular anesthesia 09/2008; 22(4):629-32. · 1.06 Impact Factor
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ABSTRACT: Incomplete recovery of neuromuscular function may impair pulmonary and upper airway function and contribute to adverse respiratory events in the postanesthesia care unit (PACU). The aim of this investigation was to assess and quantify the severity of neuromuscular blockade in patients with signs or symptoms of critical respiratory events (CREs) in the PACU.
We collected data over a 1-yr period. PACU nurses identified patients with evidence of a predefined CRE during the first 15 min of PACU admission. Train-of-four (TOF) ratios were immediately quantified in these patients using acceleromyography (cases). TOF data were also collected in a control group that consisted of patients undergoing a general anesthetic during the same period who were matched with the cases by age, sex, and surgical procedure.
A total of 7459 patients received a general anesthetic during the 1-yr period, of whom 61 developed a CRE. Forty-two of these cases were matched with controls and constituted the study group for statistical analysis. The most common CREs among matched cases were severe hypoxemia (22 of 42 patients; 52.4%) and upper airway obstruction (15 of 42 patients; 35.7%). There were no significant differences between the cases and matched controls in any measured preoperative or intraoperative variables. Mean (+/-sd) TOF ratios were 0.62 (+/-0.20) in the cases, with 73.8% of the cases having TOF ratios <0.70. In contrast, TOF values in the controls were 0.98 (+/-0.07) (a difference of -0.36 with a 95% confidence interval of -0.43 to -0.30, P < 0.0001), and no control patients were observed to have TOF values <0.70 (the 95% confidence interval of the difference was 59%-85%, P < 0.0001).
A high incidence of severe residual blockade was observed in patients with CREs, which was absent in control patients without CREs. These findings suggest that incomplete neuromuscular recovery is an important contributing factor in the development of adverse respiratory events in the PACU.
Anesthesia and analgesia 07/2008; 107(1):130-7. · 3.08 Impact Factor
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ABSTRACT: Experimental data suggest that morphine has unique antiinflammatory properties. We hypothesized that morphine, when compared with fentanyl, would attenuate the perioperative inflammatory response to cardiopulmonary bypass (CPB) when administered as part of a balanced anesthetic technique.
Thirty patients undergoing elective coronary artery bypass graft surgery were randomized to receive, in a double-blind manner, either morphine (40 mg) or fentanyl (1000 microg) as part of a standardized opioid-isoflurane anesthetic. Serum concentrations of interleukin (IL)-6 and IL-8 and expression of neutrophil surface adhesion molecules (CD 11a, CD 11b, CD 11c, and CD 18) were measured perioperatively as indicators of the inflammatory response to surgery. Core temperatures were monitored in the intensive care unit to determine the incidence of postoperative hyperthermia (temperature >38.0 degrees C).
IL-6 and IL-8 concentrations increased in all patients after CPB. The increase in serum IL-6 levels was significantly attenuated in the morphine group compared to the fentanyl group at 3 and 24 h post-CPB (P < 0.05). Reductions in expression of neutrophil adhesion molecules were observed in both groups 15 min and 3 h post-CPB; however, a significantly larger reduction in CD 11b and CD 18 expression was noted in patients receiving morphine (P < 0.05). The incidence of postoperative hyperthermia was more frequent in the fentanyl group (73%) compared to the morphine group (0%, P < 0.05).
Compared with fentanyl, the administration of morphine as part of balanced anesthetic technique suppressed several components the inflammatory response (IL-6, CD 11b, CD 18, postoperative hyperthermia) to cardiac surgery and CPB.
Anesthesia and analgesia 07/2007; 104(6):1334-42, table of contents. · 3.08 Impact Factor
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Journal of Cardiothoracic and Vascular Anesthesia 03/2007; 21(1):113-26. · 1.64 Impact Factor
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ABSTRACT: The aim of this investigation was to compare the myocardial performance index (MPI), a Doppler-derived parameter of global ventricular function, with standard echocardiographic measures of systolic and diastolic function in patients undergoing coronary artery bypass graft (CABG) surgery.
Complete two-dimensional and Doppler examinations were performed on 46 CABG patients after induction of anesthesia (baseline), 15 minutes postcardiopulmonary bypass (CPB), and at the end of the surgical procedure.
A strong inverse correlation between MPI and both fractional area change (adjusted r(2)= 0.588-0.802) and ejection fraction (adjusted r(2)= 0.576-0.656, both P < 0.001) of the left ventricle was observed throughout the intraoperative period. Following CPB, a weaker correlation was observed between MPI and overall diastolic heart function classification (adjusted r(2)= 0.224-0.268, P <0.001). Weak, though statistically significant, correlations were observed between MPI and deceleration time (P < 0.05), peak atrial reversal (AR) wave velocity (P < or =0.002), and duration of the AR wave (P < 0.05).
Our data suggest that the MPI correlates well with standard echocardiographic measures of systolic function and modestly well with overall diastolic heart function classification. The MPI may be a useful, complementary marker of global left ventricular function in patients undergoing CABG surgery.
Echocardiography 01/2007; 24(1):26-33. · 1.24 Impact Factor
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ABSTRACT: Flushing of radial arterial catheters may be associated with retrograde embolization of air or thrombus into the cerebral circulation. For embolization into the central circulation to occur, sufficient pressure must be generated during the flushing process to reverse antegrade blood flow in the arterial blood vessels of the upper extremity. This ultrasound study was designed to examine whether routine radial catheter flushing practices produce retrograde blood flow patterns in the brachial and proximal axillary arteries.
Duplex ultrasound examinations of the brachial and axillary arteries were conducted in 100 surgical patients to quantify direction and velocity of blood flow during catheter flushing. After obtaining Doppler spectral images of brachial and axillary arterial flow patterns, manual flushing was performed by injecting 10 ml flush solution using a syringe at a rate reflecting standard clinical practices. The flow-regulating device on the pressurized (300 mmHg) arterial flushing-sampling system was then opened for 10 s to deliver a rapid bolus of fluid (flush valve opening).
The rate of manual flush solution injection through the radial arterial catheter was related to the probability of retrograde flow in the axillary artery (P < 0.001). Reversed arterial flow was noted in the majority of subjects (33 of 51) at a manual flush rate of less than 9 s and in no subjects (0 of 48) at a rate 9 s or greater. Retrograde flow was observed less frequently during flush valve opening (2 of 99 patients; P < 0.001 vs. manual flushing).
Rapid manual flushing of radial arterial catheters at rates faster than 1 ml/s produces retrograde flow in the proximal axillary artery.
Anesthesiology 10/2006; 105(3):492-7. · 5.36 Impact Factor
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ABSTRACT: Experimental studies have shown that opioids protect the myocardium from ischemic injury and that opioid cardioprotection is enhanced by the coadministration of volatile anesthetics. Previous data suggest that morphine produces a more potent cardioprotective effect than fentanyl. The present study investigated the effect of the choice of intraoperative opioid (morphine or fentanyl) on recovery of myocardial function after coronary artery bypass graft (CABG) surgery.
Prospective, randomized study.
University hospital.
Forty-six patients undergoing CABG surgery.
Patients were randomly assigned to receive either morphine (40 mg) or fentanyl (1,000 mug) before cardiopulmonary bypass (CPB). Global cardiac function was assessed intraoperatively using the myocardial performance index (MPI), which combines echocardiographic parameters of both systolic and diastolic function.
The MPI (median [range]) was increased after CPB in the fentanyl group, indicating a significant worsening of global left ventricular function (0.43 [0.28-0.54] baseline; 0.49 [0.32-0.64] 15 minutes post-CPB; 0.51 [0.36-0.63] end of operation; p < 0.05 post-CPB compared with baseline). The MPI improved in the morphine group after CPB (0.44 [0.32-0.64] baseline; 0.36 [0.24-0.45] 15 minutes post-CPB; 0.34 [0.20-0.46] end of operation; p < 0.05 post-CPB compared with baseline and the fentanyl group).
In patients undergoing CPB, global ventricular function is enhanced by the administration of morphine prior to the ischemic insult of cardioplegic arrest.
Journal of Cardiothoracic and Vascular Anesthesia 08/2006; 20(4):493-502. · 1.64 Impact Factor
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Journal of Cardiothoracic and Vascular Anesthesia 07/2006; 20(3):469-70; author reply 470-1. · 1.64 Impact Factor
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Anesthesia and analgesia 02/2006; 102(1):328. · 3.08 Impact Factor
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ABSTRACT: Respiratory and pharyngeal muscle function are impaired during minimal neuromuscular blockade. Tracheal extubation in the presence of residual paresis may contribute to adverse respiratory events. In this investigation, we assessed the incidence and severity of residual neuromuscular block at the time of tracheal extubation. One-hundred-twenty patients presenting for gynecologic or general surgical procedures were enrolled. Neuromuscular blockade was maintained with rocuronium (visual train-of-four [TOF] count of 2) and all subjects were reversed with neostigmine at a TOF count of 2-4. TOF ratios were quantified using acceleromyography immediately before tracheal extubation, after clinicians had determined that complete neuromuscular recovery had occurred using standard clinical criteria (5-s head lift or hand grip, eye opening on command, acceptable negative inspiratory force or vital capacity breath values) and peripheral nerve stimulation (no evidence of fade with TOF or tetanic stimulation). TOF ratios were measured again on arrival to the postanesthesia care unit. Immediately before tracheal extubation, the mean TOF ratio was 0.67 +/- 0.2; among the 120 patients, 70 (58%) had a TOF ratio <0.7 and 105 (88%) had a TOF ratio <0.9. Significantly fewer patients had TOF ratios <0.7 (9 subjects, 8%) and <0.9 (38 subjects, 32%) in the postanesthesia care unit compared with the operating room (P < 0.001). Our results suggest that complete recovery from neuromuscular blockade is rarely present at the time of tracheal extubation.
Anesthesia & Analgesia 07/2005; 100(6):1840-5. · 3.29 Impact Factor
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ABSTRACT: Rapid flushing of radial artery catheters may result in retrograde embolization of air into the cerebral circulation. This study examined the incidence of central air embolization during and after flushing of an arterial pressure monitoring system.
One hundred adult patients undergoing cardiac surgical procedures were enrolled in this study. Ten ml of saline and blood were withdrawn into a syringe in the arterial flushing-sampling pressure system and then readministered to the patient through a 20-gauge radial artery catheter over 3-12 s. The right carotid artery, left carotid artery, and aortic arch were visualized using ultrasound imaging techniques during three manual flushes of the system. The left and right common carotid arteries were examined for the presence of macrobubbles or microbubbles using a linear array ultrasound transducer. The aortic arch was imaged using transesophageal echocardiography to detect retrograde air emboli. The severity of air embolization was quantified using a modification of an established grading system.
A total of 298 ultrasound studies in 100 patients were recorded and analyzed after radial artery catheter flushing. Two aortic arch images were not obtained because of an inability to place the probe. Most clinicians (54%) returned flush solution to patients at near-maximal injection rates (2-3 ml per second). No air emboli (macrobubbles or microbubbles) were detected in the carotid arteries or aortic arch of any subject.
Retrograde air embolization is a rare event after routine radial artery catheter flushing in adult patients with stable hemodynamic conditions.
Anesthesiology 10/2004; 101(3):614-9. · 5.36 Impact Factor
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ABSTRACT: In this study, we examined the effect of choice of neuromuscular blocking drug (NMBD) (pancuronium versus rocuronium) on postoperative recovery times and associated adverse outcomes in patients undergoing orthopedic surgical procedures. Seventy patients were randomly allocated to a pancuronium or rocuronium group. On arrival to the postanesthesia care unit (PACU) and again 30 min later, train-of-four ratios were quantified by using acceleromyography. Immediately after acceleromyographic measurements, patients were assessed for signs and symptoms of residual paresis. During the PACU admission, episodes of hypoxemia, nausea, and vomiting were recorded. The time required for patients to meet discharge criteria and the time of actual PACU discharge were noted. Forty percent of patients in the pancuronium group had train-of-four ratios <0.7 on arrival to the PACU, compared with only 5.9% of subjects in the rocuronium group (P < 0.001). Patients in the pancuronium group were more likely to experience symptoms of muscle weakness (blurry vision and generalized weakness; P < 0.001) and hypoxemia (10 patients in the rocuronium group versus 21 patients in the pancuronium group; P = 0.015) during the PACU admission. Significant delays in meeting PACU discharge criteria (50 min [45-60 min] versus 30 min [25-40 min]) and achieving actual discharge (70 min [60-90 min] versus 57.5 min [45-61 min]) were observed when the pancuronium group was compared with the rocuronium group (P < 0.001). In conclusion, our study indicates that PACU recovery times may be prolonged when long-acting NMBDs are used in surgical patients. IMPLICATIONS: Clinical recovery may be delayed in surgical patients administered long-acting neuromuscular blocking drugs. During the postanesthesia care unit admission, patients randomized to receive pancuronium (versus rocuronium) were more likely to exhibit symptoms of muscle weakness, develop hypoxemia, and require more time to meet discharge criteria.
Anesthesia & Analgesia 02/2004; 98(1):193-200, table of contents. · 3.29 Impact Factor
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ABSTRACT: The use of pancuronium in fast-track cardiac surgical patients may be associated with delays in clinical recovery. Our objective in this study was to evaluate the incidence and severity of residual neuromuscular blockade after cardiac surgery in patients randomized to receive either pancuronium (0.08-0.1 mg/kg) or rocuronium (0.6-0.8 mg/kg). Eighty-two patients undergoing cardiopulmonary bypass were randomized to a pancuronium (n = 41) or rocuronium (n = 41) group. Intraoperative and postoperative management was standardized. In the intensive care unit, train-of-four (TOF) ratios were measured each hour until weaning off ventilatory support was initiated. Neuromuscular blockade was not reversed. After tracheal extubation, patients were examined for signs and symptoms of residual paresis. When weaning of ventilatory support was initiated, significant neuromuscular blockade was present in the pancuronium subjects (TOF ratio: median, 0.14; range, 0.00-1.11) compared with the rocuronium subjects (TOF ratio: median, 0.99; range, 0.87-1.21) (P < 0.05). Patients in the rocuronium group were more likely to be free of signs and symptoms of residual paresis than patients in the pancuronium group. Our findings suggest that the use of longer-acting muscle relaxants in cardiac surgical patients is associated not only with impaired neuromuscular recovery, but also with signs and symptoms of residual muscle weakness in the early postoperative period. IMPLICATIONS: The use of long-acting muscle relaxants in fast-track cardiac surgical patients is associated with significant residual neuromuscular block in the intensive care unit, including signs and symptoms of residual paresis.
Anesthesia & Analgesia 05/2003; 96(5):1301-7, table of contents. · 3.29 Impact Factor
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ABSTRACT: Available data suggest that the choice of neuromuscular blocking drugs (NMBDs) can influence early clinical recovery of the fast-track cardiac surgical patient. The aim of this study was to use a survey tool to determine practice patterns of anesthesiologists for the use of NMBDs in the cardiac surgical setting. We mailed a survey to one third of the 3295 active members of the Society of Cardiovascular Anesthesiologists. A follow-up letter and survey were sent to each individual who did not respond to the initial mailing. After the second mailing, 459 surveys were returned, yielding a response rate of 43%. Pancuronium was listed as the primary NMBD used in the majority of patients undergoing cardiopulmonary bypass (69%) and off-pump (41%) procedures. Only 28% of respondents routinely used a peripheral nerve stimulator to monitor neuromuscular blockade in the operating room. Residual neuromuscular blockade was routinely reversed before tracheal extubation by only 9% of cardiac anesthesiologists. This survey demonstrates that long-acting NMBDs are often administered to fast-track cardiac patients. Peripheral nerve stimulator monitoring is rarely used in the operating room or intensive care unit, and reversal drugs (anticholinesterases) are infrequently administered in the postoperative period. IMPLICATIONS: This postal survey of cardiac anesthesiologists demonstrates that long-acting muscle relaxants are frequently administered to fast-track cardiac surgical patients. Neuromuscular blockade is rarely monitored or reversed in this patient population.
Anesthesia & Analgesia 01/2003; 95(6):1534-9, table of contents. · 3.29 Impact Factor
