Survey of Anesthesiology

Published by Lippincott, Williams & Wilkins
Print ISSN: 0039-6206
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Treatment of established hemorrhagic shock, produced in anesthetized dogs by a standardized technique, with chlorpromazine (2.5 mg./kg.) and/or hypothermia (immersion cooling: 25 °C.) did not increase the survival rate and tended to shorten the survival time. The cardiac output of all the treated animals, especially those subjected to chlorpromazine combined with hypothermia, failed to return to prehemorrhage levels even after reinfusion. The results suggest that once hemorrhagic shock has occurred, treatment with chlorpromazine or hypothermia is of no value and with the combination is deleterious.
 
The metabolism in vivo of several volatile anesthetics has been determined in the rat. The anesthetics studied were ether, chloroform, methoxyflurane, and halothane, all of which have been obtained isotopically labeled with chlorine-36 or carbon-14. The extent of conversion of these anesthetics to 14CO2 and urinary metabolities labeled with 14C or 36Cl is presented as a percentage of the amount of anesthetic administered.
 
Low-molecular-weight heparin (LMWH) is effective in the prevention of postoperative venous thromboembolism but does it have the safety advantages over standard heparin (SH) that have been claimed? In a multicentre randomised trial in 3809 patients undergoing major abdominal surgery (1894 LMWH, 1915 SH) heparin was given preoperatively and continued for at least 5 postoperative days. Patients were assessed in the postoperative period and were followed up for at least 4 weeks, the emphasis being on safety. Major bleeding events occurred in 69 (3·6%) patients in the LMWH group and 91 (4·8%) patients in the SH group (relative risk 0·77, 95% confidence interval 0·56-1·04; p=0·10). 93 indices of major bleeding were observed in the 69 LMWH patients and 141 in the SH patients. (p=0·058). Severe bleeding was less frequent in the LMWH group (1 0% vs 1·9%; p=0·02), as was wound haematoma (1·4% vs 2·7%; p=0·007). Bleeding episodes with LMWH were less likely to lead to further surgery to evacuate a haematoma or to control bleeding, and injection site bruising was also less common in the LMWH group. No significant differences were found in the efficacy of the two agents. Perioperative death rates were 3·3% in the LMWH group and 2·5% in the SH group; pulmonary emboli were detected in 0·7% and 0·7%; and deep-vein thrombosis was diagnosed in 0·6% of patients in each group. Follow-up was done on 91% of 3699 evaluable patients. There were 19 further deaths (10 LMWH, 9 SH group) and 25 patients with thromboembolic complications (15 and 10). Of the 3 patients with fatal pulmonary emboli during follow-up 2 had received LMWH and 1 SH. The two drugs were of similar efficacy. The primary end point, the frequency of major bleeding, showed a 23% reduction in the LMWH group, but this difference was not significant. The secondary safety end points revealed that LMWH was significantly better than SH. Fatal pulmonary embolism occurs rarely (0·09%) following discharge from hospital so the cost benefit ratio would not justify prolonged prophylaxis in this setting.
 
Background: Currently, there is not enough evidence to support the safety of the transversus abdominis plane (TAP) block when used to ameliorate postoperative pain in children. Safety concerns have been repeatedly mentioned as a major barrier to performing large randomized trials in children. The main objective of the current investigation was to determine the incidence of overall and specific complications resulting from the performance of the TAP block in children. In addition, we evaluated patterns of local anesthetic dosage selection in the same population. Methods: This was an observational study using the Pediatric Regional Anesthesia Network database. A complication from the TAP block was defined by the presence of at least one of the following intraoperative and/or postoperative factors: puncture of the peritoneum or organs, vascular puncture, cardiovascular, pulmonary and/or neurological symptoms/signs, hematoma, and infection. Additional analyses were performed to identify patterns of local anesthetic dosage. Results: One thousand nine hundred ninety-four children receiving a TAP block were included in the analysis. Only 2 complications were reported: a vascular aspiration of blood before local anesthetic injection and a peritoneal puncture resulting in an overall incidence of complications (95% CI) of 0.1% (0.02%-0.3%) and a specific incidence of complications (vascular aspiration or peritoneal puncture) of 0.05% (0.0054%-0.2000%). Neither of these complications resulted in additional interventions or sequelae. The median (95% range) for the local anesthetic dose per weight for bilateral TAP blocks was 1.0 (0.47-2.29) mg of bupivacaine equivalents per kilogram; however, subjects' weights were not sufficient to explain much of the variability in dose. One hundred thirty-five of 1944 (6.9%; 95% CI, 5.8%-8.1%) subjects received doses that could be potentially toxic. Subjects who received potentially toxic doses were younger than subjects who did not receive potentially toxic doses, 64 (19-100) months and 108 (45-158) months, respectively (P < 0.001). Conclusions: The upper incidence of overall complications associated with the TAP block in children was 0.3%. More important, complications were very minor and did not require any additional interventions. In contrast, the large variability of local anesthetic dosage used can not only minimize potential analgesic benefits of the TAP block but also result in local anesthetic toxicity. Safety concerns should not be a major barrier to performing randomized trials to test the efficacy of the TAP block in children as long as appropriate local anesthetic dose regimens are selected.
 
SUMMARY Previous studies have established that no change occurs in metabolic state in normo-thcrmic patients undergoing major vascular surgery with aorto-iliac occlusion. However, it was stressed that this was true only if the cardiac output was undiminished and the transfusion of acid-citrate-dextrose blood was not sustained at rates over 100 ml/min. In this study eighteen patients undergoing major vascular surgery, who were anaesthetized using a relaxant/hyperventilation technique, were similarly investigated These patients developed accidental hypothermia and, owing to the presence of hypocapnia, probably had a decreased cardiac output. Deliberate overtransfusion was practised during clamping to reduce episodes of marked hypotension on release of the clamps. No significant change in metabolic state was seen.
 
SUMMARY Tachyphylaxis following repeated administration of alpha-adrenergic-receptor blocking agents is a troublesome complication, especially during the management oo phacochromocytoma. Although it has been indicated that tachycardia is a manifestation heta-adrenergic-receptor blocking agent such as propranolol effective in preventing arrhythmias, but it is also of significant value in overcoming tachyphylaxis following repeated adminisration of alpha-adrenergic-receptor blocking agents.
 
A case of familial dysautonomia (Riley-Day syndrome) is presented. Details of the anaesthetic technique employed whilst a gastrostomy and hernia repair were performed are reported. Moderately heavy sedation and propranolol together with atropine as the premedication employed may have been responsible for the uneventful course of anaesthesia. The pathophysiology of the condition is presented in terms of the implications for the anaesthetist who undertakes the management of such a case.
 
SUMMARY True anaphylactic shock is exceedingly rate during general anesthesia and has never been reported with intravenous penicillin. This 47-year-old white female who received intravenous penicillin during elective debridement of the femoral head rapidly developed classical manifestations of anaphylactic shock incuding serve bronchospasm. After discontinuing penicillin and halothane, intensive supportive care brought about an uneventful recovery. Halothane anasthesia may have reduced the severity of bronchospasm, thereby indirectly aiding efforts to reverse anaphylaxis.
 
IN a previous paper (Stevenson, 1960) the changes in the blood electrolytes which may occur as a result of anaesthesia in dogs have been discussed. This paper describes how such changes may be modified by the use of suxamethonium chloride as a muscle relaxant during anaesthesia. Perry and Zaimis (1954) showed that suxamethonium causes the release of potassium from perfused voluntary muscle, while Klupp, Kraupp, Honetz, Kobinger and Loudin (1954) demonstrated that in dogs depolarizing muscle relaxants, including suxamethonium, will cause an increase in the plasma potassium concentration which they claimed to be biphasic. These workers claimed that the potassium concentration could be restored to the normal value by the administration of d - tubocurarine subsequent to the injection of suxamethonium . Paton (1956) has shown in cats that the injection of suxamethonium will cause an increase in the plasma potassium concentration due to release from skeletal muscle which is associated with a partial depolarization of the muscle surface. METHODS
 
Certain aspects of ventilatory function were studied before and after induction of high epidural analgesia in patients with normal and diseased respiratory systems. The changes in tidal volume, minute volume and vital capacity in both groups were small. Somewhat greater reductions in peak expiratory flow rate were observed but it is unlikely that the ability to cough is much impaired during epidural block. It is concluded that no important degree of respiratory paralysis is present during epidural block. The value of epidural analgesia for patients with poor pulmonary function and in the relief of postoperative pain is discussed.
 
Ketamine, in subanesthetic doses, produces systemic analgesia in chronic pain settings, an action largely attributed to block of N-methyl-D-aspartate receptors in the spinal cord and inhibition of central sensitization processes. N-methyl-D-aspartate receptors also are located peripherally on sensory afferent nerve endings, and this provided the initial impetus for exploring peripheral applications of ketamine. Ketamine also produces several other pharmacological actions (block of ion channels and receptors, modulation of transporters, anti-inflammatory effects), and while these may require higher concentrations, after topical (e.g., as gels, creams) and peripheral application (e.g., localized injections), local tissue concentrations are higher than those after systemic administration and can engage lower affinity mechanisms. Peripheral administration of ketamine by localized injection produced some alterations in sensory thresholds in experimental trials in volunteers and in complex regional pain syndrome subjects in experimental settings, but many variables were unaltered. There are several case reports of analgesia after topical application of ketamine given alone in neuropathic pain, but controlled trials have not confirmed such effects. A combination of topical ketamine with several other agents produced pain relief in case, and case series, reports with response rates of 40% to 75% in retrospective analyses. In controlled trials of neuropathic pain with topical ketamine combinations, there were improvements in some outcomes, but optimal dosing and drug combinations were not clear. Given orally (as a gargle, throat swab, localized peritonsillar injections), ketamine produced significant oral/throat analgesia in controlled trials in postoperative settings. Topical analgesics are likely more effective in particular conditions (patient factors, disease factors), and future trials of topical ketamine should include a consideration of factors that could predispose to favorable outcomes.
 
An outline has been presented of the experience gained from 180 patients with intracardiac defects and major vascular lesions who were subjected to a combination of extracorporeal circulation and induced hypothermia. Anesthesia was maintained with an ultra short-acting barbiturate, nitrous oxide and oxygen and succinylcholine. In those patients requiring cardioplegia, arrest of the heart was produced by inducing profound hypothermia with a heat exchanger incorporated into the extracorporeal circuit. Of the various monitoring aids employed, the electroencephalogram was found to be the most sensitive indicator of the status of the patient. The various potential factors which may lead to the development of respiratory and metabolic acidosis have been discussed. It is becoming apparent that a patient can be maintained during the operative phase with increasing ease, but serious complications may develop in the postoperative period. In the postoperative period difficulties have centered around: (1) regulation of blood volume, (2) pulmonary function, (3) the problem of acidosis and (4) complications of the organic disease of the patient.
 
An attempt to estimate residual neuromuscular blockade after the administration of anti-depolarizing relaxants to anaesthetized patients is described. A train of four supra-maximal nerve stimuli was applied to the ulnar nerve and the twitch response (mechanical or electrical) was recorded. The frequency of the train used was 2–2.4 Hz with an interval of 10 seconds between the trains. Clinical recovery from the relaxant was assessed by the ability to lift the head. The ratio of the height of the fourth response of the train to that of the first (ratio (c)) gave a good indication of the degree of residual neuromuscular block as indicated by this simple clinical test. As ratio (c) increased muscle power improved. Obvious muscle weakness was associated with values of ratio (c) of less than 0.6.
 
SUMMARY We have measured, in 21 horizontal and 18 25° head-down anaesthetized, artificially ventilated patients, the effea of progressive increases of intra-abdominal pressure (IAP) before, during and after laparoscopy, on: CVP, intrathoracic pressure (ITP), femoral venous pressure (FVP), cardiac output (Q), heart rate, mean arterial blood pressure (MAP), peak airway pressure, FF/QO, and arterial blood-gas tensions. FVP paralleled the increase of IAP. In both horizontal and tilted patients increases of IAP to around 20 cm H,0 were accompanied by increases of CVP (horizontal: 4.6 cm H3O; tilted: 10.2 cm H,O), by smaller increases of ITP (horizontal: 1.8 cm 11,0; tilted: 32 cm H,O), and by increases of Q (from 3.9 l./min per 70 kg to 5.0 l./min per 70 kg in horizontal position; and from 4.8 L/min per 70 kg to 5.3 L/min per 70 kg in tilted patients). Greater increases of IAP to around 40 cm HjO were accompanied by falls of CVP and Cj (to 4.4 l./min per 70 kg in both positions), accompanied by parallel changes of MAP and by moderate tachycardia. There was no arterial hypoxaemia, Pao* rising from 132.0 mm Hg to 135.4 mm Hg in the horizontal patients, and from 151.3 mm Hg to 155.2 mm Hg in the tilted patients; increases of Paoo3 were slight (from 28.6 mm Hg to 32.4 mm Hg in the horizontal patients, and from 25.3 to 30.9 mm Hg in the tilted patients).
 
SUMMARY Pancuronium bromide was given to five patients requiring operations for terminal renal insufficiency. Reversal of neuromuscular blockade was clinically satisfactory in all patients.
 
A case is described of myoglobinuria following general anaesthesia in which suxamethonium chloride was used as a relaxant.
 
Cyclopropane decreases forearm blood flow and, as the mean arterial pressure is little altered, vascular resistance is increased. The extent of the increase in vascular resistance is directly proportional to the concentration of cyclopropane. The vasoconstriction appears to be due to the direct action of cyclopropane on the blood vessel walls or associated nerve endings, possibly in conjunction with an enhanced effect of noradrenaline, and an increase in circulatory catecholamines. The earlier reports state that cyclopropane increases forearm blood flow but the data which are presented indicate that surgery, and not cyclopropane per se, may be the cause of this increased flow.
 
One hundred general surgical patients were subjected to a form of personality assessment (Eysenck and Eysenck, 1964) the day before operation. Anaesthesia was standardized using light general anaesthesia, a muscle relaxant and controlled ventilation. The day after surgery patients filled in a standardized postoperative questionnaire about complaints concerning their visit to theatre. The patients were more “neurotic” (had higher N scores) than the general population; they also had a higher lie (L) score, and this tended to increase with age. The N score was greater in those awaiting upper abdominal operations than in those awaiting other procedures, and greater in females than in males. Pain was the most conspicuous postoperative complaint, despite the use of conventional analgesia. Preoperative anxiety was also prominent, as were complaints related to the passage or presence of a nasogastric tube. There was a positive correlation between N score and complaints of anxiety, and between N score and total number of complaints, but not between N score and complaints of pain.
 
We carried out a multicenter randomized, placebo-controlled trial to evaluate the efficacy and safety of surfactant in the treatment of respiratory distress syndrome. The study population was made up of newborn infants weighing 750 to 1750 g who were receiving assisted ventilation with 40 percent or more oxygen. The eligible infants received a single dose of either surfactant (100 mg of phospholipid per kilogram of body weight [4 ml per kilogram]) or an air placebo (4 ml per kilogram), administered into the trachea within eight hours of birth by an investigator not involved in the clinical care of the infant. When compared with the infants who received the placebo (n = 81), the infants who were treated with surfactant (n = 78) had a 0.12 greater average increase in the ratio of arterial to alveolar oxygen tension (P < 0.0001), a 0.20 greater average decrease in the fractional inspiratory oxygen concentration (P < 0.0001), and a 0.26-kPa greater average decrease in the mean airway pressure (P < 0.0001) during the 72 hours after treatment. Pneumothorax was less frequent among the infants treated with surfactant than in the control group (13 percent vs. 37 percent; P = 0.0005). There were no statistically significant differences between the groups in the proportion of infants in each of five ordered clinical-status categories on day 7 (P = 0.08) or day 28 (P = 0.75) after treatment. There were also no significant differences between the groups in the frequency of bronchopulmonary dysplasia, patent ductus arteriosus, necrotizing enterocolitis, or periventricular-intraventricular hemorrhage. In each group, 17 percent of the infants died by day 28. We conclude that treatment with the single-dose surfactant regimen used in this study reduces the severity of respiratory distress during the 72 hours after treatment and decreases the frequency of pneumothorax, but that it does not significantly improve clinical status later in the neonatal period and does not reduce neonatal mortality. Further study of different surfactant regimens and patient-selection criteria will be required to determine whether this initial improvement can be translated into reductions in mortality or serious morbidity.
 
SUMMARY A 43-year-old male who had previously sustained gunshot wounds of both legs, for which amputations were performed, underwent operation for disobliteration of the right femoral and left common iliac arteries. Persistent convulsions developed early in the postoperative period. Treatment and possible precipitating factors are discussed.
 
Limb blood flow was studied in twelve subjects, during trichloroethylene anaesthesia, using venous occlusion plethysmography. There was no significant alteration in blood flow or vascular resistance in the series as a whole. In some cases there was evidence of peripheral vasodilatation which was not abolished by nerve block. This was associated with tachypnoea and it was considered to be the result of the action of trichloroethylene on the blood vessel wall. Vasodilatation during trichloroethylene anaesthesia was replaced by vasoconstriction when the tachypnoea was abolished by means of intravenous pethidine. It is suggested that this is a compensatory vasoconstriction in response to a fall in the cardiac output, brought about by the combined effects of the narcotic and the anaesthetic agent.
 
SUMMARY Administration of nitrous oxide in order to provide analgesia is now more practicable because improved apparatus is available. It is well accepted that nitrous oxide is satisfactory for the relief of pain in labour and to provide analgesia for conservative dental procedures. Its use has been extended, too, to include pain in myocardial ischaemia, acute trauma, and after surgical operations. Apart from its value in mitigating pain, its value in other conditions is considered. These include the management of head injuries, bronchial asthma and some neoplastic conditions. The principal limitation of nitrous oxide therapy is that continuous treatment must be limited to 24 or at the most 48 hours because of the risk of leucopenia.
 
The clinical triad of micrognathia (small mandible), glossoptosis (backward, downward displacement of the tongue), and airway obstruction defines the Pierre Robin sequence (PRS). Airway obstruction and respiratory distress are clinical hallmarks. Patients may present with stridor, retractions, and cyanosis. Severe obstruction results in feeding difficulty, reflux, and failure to thrive. Treatment options depend on the severity of airway obstruction and include prone positioning, nasopharyngeal airways, tongue lip adhesion, mandibular distraction osteogenesis, and tracheostomy. The neonate and infant with PRS require care from multiple specialists including anesthesiology, plastic surgery, otolaryngology, speech pathology, gastroenterology, radiology, and neonatology. The anesthesiologist involved in the care of patients with PRS will interface with a multidisciplinary team in a variety of clinical settings. This perioperative review is a collaborative effort from multiple specialties including anesthesiology, plastic surgery, otolaryngology, and speech pathology. We will discuss the background and clinical presentation of patients with PRS, as well as some of the controversies regarding their care.
 
SUMMARY During a 21-month period, 1223 gynaecological patients were studied consecutively during 3 hours in the recovery room. Three primary anaesthetics were randomly utilized: (a) cyclopropane, with or without thiopentone; (b) halothane, with or without thiopentone; and (c) thiopentone-nitrous oxide-oxygen. Ten per cent of the patients received miscellaneous agents. The overall incidence of emesis was approximately 29 per cent. Cyclopropane was associated with a significantly higher incidence of emesis than were halothane and thiopentone-nitrous oxide-oxygen. Thiopentone induction followed by a primary inhalation agent was associated with a lower incidence of emesis than was induction with the primary agent alone. The duration of anaesthesia, the lithotomy in contrast to the supine position, the type of premedication and the specific type of gynaecological surgery were not significantly influential nor were many miscellaneous physical or pharmacological factors. The chief conclusion to be drawn from this study is that the primary anaesthetic agent and the persence or absence of a thiopentone induction remained the most vital influences on the incidence of post-anaesthetic emesis in the recovery room.
 
Top-cited authors
Joanna E Siegel
  • U.S. Department of Health and Human Services
Norman Daniels
  • Harvard University
Lars Svensson
  • Cleveland Clinic
Vinod Thourani
  • Emory University
Duolao Wang
  • London School of Hygiene and Tropical Medicine