Peri-operative shivering

Comparison of the effectiveness of dexmedetomidine, meperidine and ketamine in the prevention of postoperative shivering

OBJECTIVE

To compare the prophylactic effectiveness of dexmedetomidine, meperidine, and ketamine for postoperative shivering.

MATERIALS AND METHODS

A randomized, controlled, double-blind, clinical trial, including 160 patients (ASA I - II) undergoing surgical procedures under general anaesthesia for longer than one hour. They were randomly assigned to four groups to receive a single intravenous dose: Dexmedetomidine 1ug/kg (group A, n=33), meperidine 0.4mg/kg (group B, n=38), ketamine 0.5mg/kg (groupC, n=40), or 0.9% saline solution (group D, n=45), administered 20min before the skin suture. To avoid bias, the anaesthetic induction and maintenance technique, as well as postoperative follow-up was standardised.

RESULTS

For any level of shivering, the greatest incidence was observed in the placebo group (47%) (P<.01). The greatest effect on shivering level 3 and 4 occurred in the placebo group (22% and 18%, respectively). For levels 3 and 4 during follow-up, there was not a single case of shivering at any time in the meperidine group (P<.01). The placebo group (38%) had the highest proportion of patients requiring treatment for post-operative shivering (P<.01).

CONCLUSION

Meperidine given intravenously in a single dose of 0.4mg/kg is a useful means for preventing postoperative shivering.

Role of butorphanol and ondansetron premedication in reducing postoperative shivering after general and spinal anesthesia: A randomized comparative study from North India

Background:

Postoperative shivering (PAS) is a common problem following general and spinal anesthesia and may lead to multiple complications. This placebo-controlled, randomized study was performed to evaluate the efficacy of Ondansetron and butorphanol premedication reduces shivering after general and spinal anaesthesia.

Aims:

The aim of this study to highlight the efficacy of Butorphenol and ondosteron in controlling postoperative shivering.

Materials and Methods:

This clinical trial included 180 patients scheduled for elective general surgery, E.N.T., Ophthamological operations, randomly divided to six groups. Three groups in which General Anaesthesia was used i.e. Group 1-ondansetron 8 mg intravenously(IV).Group 2 butorphanol 2 mg IV and Group 3 – saline 4 ml IV. And three groups where spinal Anaesthesia was used i.e. Group 4-Ondosteron 8 mg IV, Group 5 butorphanol 2 mg IV and Group 6 – saline 4 ml IV 3-5 minutes before anaesthesia. Patients were observed in terms of vital signs, side effects and shivering.

Settings and Design:

The type of the study was double blind randomized trial.

Statistical Analysis Used:

Statistical Package for Social Sciences version 13.0 statistical analysis software.

Results:

Postoperative shivering was observed in 15.5%, 22.2% and 60% in general anaesthesia groups I II and III respectively. The reduction of core and dermal temperature during the anaesthesia and recovery, changes in systolic and diastolic blood pressure and heart rate were similar in all three groups (i.e. Group I,II,III). In spinal anaesthesia groups, PAS occurred 10%, 13.3% and 43.3% in group IV, V, VI respectively. The reduction of core temperature is similar in all three groups of spinal anaesthesia. But heart rate and mean arterial pressure increase were significant in control saline group in post operative recovery time. No complication seen in any of the six groups.

Conclusion:

This study suggested that use of Butorphanol and Ondansteron both are effective in reducing the incidence of PAS after general and spinal anaesthesia.

Effect of palonosetron on postanesthetic shivering after propofol-remifentanil total intravenous anesthesia

PURPOSE

The authors conducted a prospective, randomized, double-blind study to evaluate the anti-shivering efficacy of palonosetron for patients after gynecological laparoscopy under total intravenous propofol-remifentanil anesthesia.

METHODS

Sixty female patients were randomly assigned to one of two groups and administered palonosetron 0.075 mg (palonosetron group, n = 30) or the same volume of normal saline (control group, n = 30) immediately after anesthesia induction. Anesthesia was induced and maintained with propofol and remifentanil, using a target-controlled infusion device. Esophageal and index finger temperatures were measured immediately after anesthesia induction (baseline) and at 15-min intervals until the end of the surgery. Postanesthetic shivering and side effects were assessed in a postanesthetic care unit.

RESULTS

Incidence of shivering was comparable in the control and palonosetron groups (10/30 vs. 8/30, respectively, P = 0.779). No significant intergroup differences were observed between esophageal and index finger temperatures. Compared with baseline values, esophageal temperatures decreased immediately after pneumoperitoneum in the control group and from 30 min after pneumoperitoneum in the palonosetron group.

CONCLUSION

Use of palonosetron (0.075 mg) did not reduce the incidence of postanesthetic shivering after gynecological laparoscopy under propofol-remifentanil anesthesia. Further study including other 5-HT3 antagonists or male patients would elucidate the effect of palonosetron on shivering after propofol-remifentanil anesthesia.

Effects of clonidine premedication upon postoperative shivering and recovery time in patients with and without opium addiction after elective leg fracture surgeries

BACKGROUND

Opium is a highly addictive agent and the most common narcotic often misused in Iran. The pharmacokinetic of anesthetic drugs in patients with opium addiction is one of the great challenges for anesthesiologists. Hemodynamic instability and postoperative side effects are of these challenges which should be managed correctly.

OBJECTIVES

In this study we aimed to assess the effects of clonidine upon post anesthesia shivering and recovery time in patients with and without opium addiction after general anesthesia to decrease the subsequent complications related to the shivering and elongation of recovery time.

PATIENTS AND METHODS

In a randomized clinical trial, 160 patients candidates for elective leg fracture operations under general anesthesia were studied in four groups of 40 patients: Group 1 (placebo 1) were patients without addiction who got placebo 90 minutes before the operation. Group 2 (placebo 2) were patients with opium addiction which received placebo as group 1. Group 3 (Clonidine 1) patients without addiction who got clonidine 90 minutes before the operation and group 4 (Clonidine 2) who were opium addicted ones which received clonidine as premedication.

RESULTS

None of the patients with and without addiction in clonidine groups had shivering after the operation but in placebo groups shivering was observed and the difference between clonidine and placebo groups was statistically significant (P < 0.01). Recovery time in clonidine groups of patients with and without addiction was less than placebo ones (both P < 0.01) which the magnitude of difference was higher in opium addicted than non-addicted patients (P = 0.04).

CONCLUSIONS

Premedication with clonidine in patients with and without opium addiction can be effective to decrease the incidence of shivering and recovery time after operation.

Pre-induction low dose pethidine does not decrease incidence of postoperative shivering in laparoscopic gynecological surgeries

OBJECTIVES

The incidence of shivering in patients undergoing a laparoscopic procedure is stated to be about 40%. A majority of laparoscopic gynecological procedures are taken up on an outpatient basis. Postoperative shivering may delay hospital discharge and is a common cause of discomfort in patients recovering from anesthesia.

AIMS

To determine the effect of pre-induction, low-dose pethidine on postoperative shivering in patients undergoing laparoscopic gynecological surgeries.

SETTING AND DESIGN

Sixty females between 25 and 35 years of age, of American Society of Anesthesiologists (ASA) class 1 and 2, were randomly divided into three groups of 20 patients each. Group I and II patients received i.v. pethidine 0.3 mg/kg and 0.5 mg/kg, respectively, while Group III received i.v. 0.9% normal saline just before induction of general anesthesia. Temperature of the Operating Room and the Post Anesthesia Care Unit was standardized and all fluids given during the study period were warmed to 37°C.

MATERIALS AND METHODS

Temperature, measured with a tympanic membrane probe, was recorded preoperatively, after induction of anesthesia, on arrival at the Post Anesthesia Care Unit, and postoperatively at 15 minutes and 30 minutes. Shivering was graded (0 - 4 scale) at arrival of the patients to the PACU and every five minutes thereafter, up to 30 minutes.

STATISTICAL ANALYSIS

ANOVA, Chi-square test, Kruskal-Wallis ANOVA and Mann-Whitney U tests were used. A P-value of less than 0.05 was considered significant.

RESULTS

Core body temperatures were statistically insignificant between groups at pre-induction, post-induction, and in the PACU (P > 0.05). At the end of surgery, shivering was present in 18 patients (30%). In groups I, II, and III, six (30%), three (15%), and nine (45%) patients shivered, respectively. The differences in incidence and grading of shivering among groups was found to be statistically insignificant (P > 0.05). The core body temperature of shiverers and non-shiverers were compared. In the PACU at 0, 15, and 30 minutes, the temperature among shiverers was significantly lower than that in the non-shiverers. Rescue drug i.v. pethidine 20 mg was given to patients with shivering grade ≥2. None of the patients had shivering after 10 minutes.

CONCLUSIONS

Prophylactic pre-induction, low-dose pethidine does not have major role in preventing postoperative shivering.

Intrathecal sufentanil decreases the median effective dose (ED50) of intrathecal hyperbaric ropivacaine for caesarean delivery

BACKGROUND

The addition of opioid to local anaesthetics has become a well-accepted practice of spinal anaesthesia for caesarean delivery. Successful caesarean delivery anaesthesia has been reported with the use of a low dose of intrathecal hyperbaric ropivacaine coadministered with sufentanil. This prospective, double-blinded study determined the median effective dose (ED50) of intrathecal hyperbaric ropivacaine with and without sufentanil for caesarean delivery, to quantify the sparing effect of sufentanil on the ED50 of intrathecal hyperbaric ropivacaine.

METHODS

Sixty-four parturients undergoing elective caesarean delivery with combined spinal-epidural anaesthesia were randomized into two groups: Group R (ropivacaine) and Group RS (ropivacaine plus sufentanil 5 microg). The initial dose of ropivacaine was 13 mg in Group R and 10 mg in Group RS. The effective dose was defined as a T(6) level attained within 10 min and no supplemental epidural anaesthetic required during surgery. Effective or ineffective responses determined, respectively, a 0.3 mg decrease or increase of the dose of ropivacaine for the next patient using an up-down sequential allocation.

RESULTS

The ED50 of intrathecal ropivacaine was 11.2 mg [confidence interval (CI) 95%: 11.0-11.6] in Group R vs. 8.1 mg (CI 95%: 7.8-8.3) in Group RS. Motor block was markedly more intense in Group R than in Group RS, and the incidence of shivering was lower in Group RS than in Group R. There were no differences in the onset time of sensory block or motor block, in the incidence of hypotension, nausea and vomiting.

CONCLUSION

Intrathecal sufentanil 5 microg produced a 28% reduction of ED50 of intrathecal hyperbaric ropivacaine for caesarean delivery.

Endotoxin-like reaction following once-daily gentamicin

An endotoxin-like reaction is a host response to an agent that induces the release of endogenous pyrogens, including cytokines. The typical reaction that is associated with gentamicin is fever and chills, rigor, shivering, tachycardia with hypertension or hypotension, respiratory symptoms and muscle cramps. We report a case of a 92-year-old patient who developed an endotoxin-like reaction in the post-operative recovery unit following 200 mg of gentamicin. The reported side effect is not included in the drug sheet or in the British National Formulary. No similar incidents were reported in the UK. We discuss the clinical picture of this rare event, along with a review of the literature and recommendations.

Dexmedetomidine and postoperative shivering in patients undergoing elective abdominal hysterectomy

BACKGROUND

Post-anaesthetic shivering is one of the most common complications, occurring in 5-65% of patients recovering from general anaesthesia and 33% of patients receiving epidural anaesthesia. Our objective was to investigate the efficacy of intraoperative dexmedetomidine infusion on postoperative shivering.

METHODS

Ninety female patients, ASA I-II, 35-60 yr old, scheduled for elective total abdominal hysterectomy with or without bilateral salpingo-oophorectomy were randomized into two groups. After endotracheal intubation one group received normal saline infusion and the other received dexmedetomidine as a loading dose of 1 microg kg(-1) for 10 min followed by a maintenance infusion of 0.4 microg kg(-1) h(-1). In the recovery room, pain was assessed using a 100 mm visual analogue scale and those patients who had a pain score of more than 40 mm were administered 1 mg kg(-1) intramuscular diclofenac sodium. Patients with shivering grades more than 2 were administered 25 mg intravenous meperidine. Patients were protected with passive insulation covers.

RESULTS

Post-anaesthetic shivering was observed in 21 patients in the saline group and in seven patients in the dexmedetomidine group (P = 0.001). Shivering occurred more often in the saline group. The Ramsay Sedation Scores were higher in the dexmedetomidine group during the first postoperative hour. Pain scores were higher in the saline group for 30 min after the operation. The need for intraoperative atropine was higher in the dexmedetomidine group. Intraoperative fentanyl use was higher in the saline group. Perioperative tympanic temperatures were not different between the groups whereas postoperative measurements were lower in the dexmedetomidine group (P < 0.05).

CONCLUSION

Intraoperative dexmedetomidine infusion may be effective in the prevention of post-anaesthetic shivering.

Urapidil does not prevent postanesthetic shivering: a dose-ranging study

PURPOSE

To investigate the effect of 0.2 mg x kg(-1), 0.3 mg x kg(-1) and 0.4 mg x kg(-1) urapidil on the incidence and severity of postanesthetic shivering.

METHODS

One hundred and fifty patients (ASA I-III) scheduled for elective abdominal, urologic or orthopedic surgery under standardized general anesthesia were randomly allocated to one of five groups (each group n=30) using a double-blind protocol: group A received 0.2 mg x kg(-1) urapidil, group B: 0.3 mg x kg(-1) urapidil, group C: 0.4 mg x kg(-1) urapidil, group D: 3 microg x kg(-1) clonidine (positive control group), and group E: saline 0.9% as placebo (negative control group). Postanesthetic shivering was scored using a five-point scale.

RESULTS

Twelve patients of group A, 11 of group B, nine of group C, three of group D and 14 of group E showed signs of postanesthetic shivering. Postanesthetic shivering was significantly decreased in the clonidine group compared to the three urapidil groups and the placebo group. Significantly less patients treated with clonidine needed anti-shivering therapy. There were no significant differences between the urapidil and placebo groups. Therapeutic interventions for hemodynamic effects were not required in any group. Time to extubation, but not time to discharge, was prolonged in the clonidine group.

CONCLUSION

Urapidil showed no beneficial effect on shivering in any of the doses evaluated, whereas prophylactic administration of clonidine was effective in preventing postanesthetic shivering.

A comparison between meperidine, clonidine and urapidil in the treatment of postanesthetic shivering

Postanesthetic shivering can be treated with many types of drugs. We compared the effects of meperidine, clonidine, and urapidil on postanesthetic shivering. Sixty patients shivering during recovery from general anesthesia were treated in a randomized, double-blinded fashion with 25 mg meperidine IV, 0.15 mg clonidine IV, or 25 mg urapidil IV in three separate groups of 20 patients each. If shivering did not stop within 5 min, the treatment was repeated once; clonidine was replaced with saline for the second dose. Rectal temperature, arterial blood pressure, heart rate, SaO(2) and vigilance were monitored. Clonidine stopped shivering in all 20 patients. A single dose of meperidine stopped the shivering in 18 of 20 patients, with the other 2 patients needing a second dose. Urapidil was less effective: the first dose stopped the shivering in only six patients; the second dose was effective in another six; the drug was ineffective in 8 of 20 patients. Meperidine and clonidine were both nearly 100% effective in treating postanesthetic shivering without negative side effects. By comparison, urapidil was only effective in 60% of patients treated (P <0.01).

IMPLICATIONS

Patients shivering during recovery from general anesthesia were treated in a randomized double-blinded fashion with meperidine, clonidine, or urapidil. Meperidine and clonidine were both very effective, whereas urapidil was only effective in 60% of patients treated.

Clinical effectiveness in the post-anaesthesia care unit: how nursing knowledge contributes to achieving intended patient outcomes

Clinical effectiveness in the post-anaesthesia care unit: how nursing knowledge contributes to achieving intended patient outcomes This paper reports part of an ongoing study on how nursing knowledge develops in practice and influences patient outcomes. The practice focus is post-anaesthesia nursing, an area which has been under-represented in nursing research. A qualitative approach was used to explore narrative data, collected by in-depth interviews, with 32 experienced post-anaesthesia nurses. Data analysis and interpretation were informed by a phenomenological perspective consistent with a research focus on individual experiences. Interpretation of the narratives gave rise to a description of knowledge development which occurred as nurses gained experience, drew on the available knowledge base, and used knowledge in practice. This led to the identification and description of 'referential' and 'effective' types of knowledge. Referential knowledge comprises the variety of external knowledge sources available to inform practice. When referential knowledge was incorporated into the personal knowledge of the individual nurse in everyday practice, it was transformed into effective knowledge which was used by nurses to achieve desired patient outcomes. The study findings indicate that nurses used effective knowledge as evidence for decision making and interventions in everyday practice. The key finding of the study is that effective nursing knowledge requires practice for its development.

Nefopam and clonidine in the prevention of postanaesthetic shivering

Postanaesthetic shivering affects up to 70% of patients after general anaesthesia, and may be very distressing. Various drugs have been used to treat or prevent postanaesthetic shivering, but the ideal one has not yet been found. Sixty patients undergoing elective abdominal or orthopaedic surgery under general anaesthesia were included in a randomised, double-blind study. Patients received clonidine (3 microgram.kg-1), nefopam (0.15 mg.kg-1) or saline 0.9% as a placebo at the end of surgery, prior to extubation. Nefopam and clonidine significantly reduced the incidence and severity of shivering in comparison with the placebo. The recovery time, between the end of anaesthesia and extubation, was significantly longer in the clonidine-treated patients [13.6 (5.2) min] than in either the nefopam [9.6 (2.8) min] or the placebo [10.0 (5.4) min] groups. Mean arterial blood pressure and heart rate were significantly lower in the clonidine group compared with both other groups. Our results suggest that nefopam and clonidine are effective in the prevention of postanaesthetic shivering. However, following clonidine administration the recovery time was prolonged and hypotension was significantly greater than after nefopam.

Dexamethasone decreases the incidence of shivering after cardiac surgery: a randomized, double-blind, placebo-controlled study

Shivering after cardiac surgery is common, and may be a result of intraoperative hypothermia. Another possible etiology is fever and chills secondary to activation of the inflammatory response and release of cytokines by cardiopulmonary bypass. Dexamethasone decreases the gradient between core and skin temperature and modifies the inflammatory response. The goal of this study was to determine whether dexamethasone can reduce the incidence of shivering. Two hundred thirty-six patients scheduled for elective coronary and/or valvular surgery were randomly assigned to receive either dexamethasone 0.6 mg/kg or placebo after the induction of anesthesia. All patients received standard monitoring and anesthetic management. After arrival in the intensive care unit (ICU), nurses unaware of the treatment groups recorded visible shivering, as well as skin and pulmonary artery temperatures. Analysis of shivering rates was performed by using chi2 tests and logistic regression analysis. Compared with placebo, dexamethasone decreased the incidence of shivering (33.0% vs 13.1%; P = 0.001). It was an independent predictor of reduced incidence of shivering and was also associated with a higher skin temperature on ICU admission and a lower central temperature in the early postoperative period.

IMPLICATIONS

Dexamethasone is effective in decreasing the incidence of shivering. The effectiveness of dexamethasone is independent of temperature and duration of cardiopulmonary bypass. Shivering after cardiac surgery may be part of the febrile response that occurs after release of cytokines during cardiopulmonary bypass.

Postanaesthetic shivering in children

This study was designed to assess the incidence, severity and possible aetiological factors of postanaesthetic shivering in children. Three hundred and seventy-six children undergoing general anaesthesia were enrolled in the study. Tympanic membrane temperatures were recorded pre-operatively and every 15 min postoperatively in the recovery room until discharge to the ward. Also recorded were all anaesthetic data including fluid administration, methods of temperature preservation used, sedation scores and shivering (using a four-point scale). The overall incidence of shivering was 14.4%. Multiple regression analysis identified three factors that were significantly related to shivering: age, the administration of atropine and peri-operative temperature changes. Children who shivered rewarmed faster in the recovery room.

The effect of prophylactic clonidine on postoperative shivering. A large prospective double-blind study

The primary goal of this study was to assess the influence of clonidine administered after induction on postoperative shivering after elective peripheral surgery. The effect of clonidine on intra-operative haemodynamics (blood pressure and heart rate) during the first 30 min after induction and on the postoperative sedation of the patient was also investigated. Two hundred and eighty male ASA 1 and 2 patients, undergoing elective peripheral surgery were randomly administered either placebo or clonidine 2 micrograms.kg-1 intravenously over 10 min after induction of anaesthesia. Clonidine was found to reduce the total incidence (p = 0.024), the severity (p = 0.005) and the duration (p = 0.01) of postoperative shivering. Clonidine did not increase postoperative sedation or diminish overall consciousness. We conclude that administration of clonidine 2 micrograms.kg-1 intravenously after induction of anaesthesia is safe and reduces postoperative shivering in this group of patients.

Post-anaesthetic shaking

Although shaking in the post-anaesthetic period is common, the cause of this phenomenon is obscure. Many predisposing factors have been identified, but the medical treatments and measures of care for patients with post-anaesthetic shaking are as controversial as the causes.

Propofol and postanaesthetic shivering

Sixty ASA grade 1 unpremedicated patients scheduled for minor elective surgery were randomly allocated to receive general anaesthesia consisting of either propofol-nitrous oxide in oxygen or a conventional technique of thiopentone-isoflurane-nitrous oxide-oxygen. Baseline axillary temperature readings, duration of operation and intra-operative decrease in axillary temperature were similar in both groups. The patients who received propofol-nitrous oxide-oxygen anaesthesia had a significantly lower incidence of postanaesthetic shivering than the control group. A propofol-nitrous oxide-oxygen technique may be preferable when postanaesthetic shivering is deemed undesirable.

Anaesthesia for caesarean section in a patient with myotonic dystrophy receiving warfarin therapy

A 31-yr-old parturient with myotonic dystrophy and asthma presented for elective Caesarean section. The patient was receiving warfarin having had two previous episodes of thromboembolism. Anticoagulation was subsequently provided by heparin in the weeks prior to delivery. The combination of the patient's medical conditions and the continuing need for anticoagulation presented a considerable anaesthetic problem in planning anaesthesia and analgesia for both elective and emergency delivery. Heparin was discontinued on the day prior to surgery and restarted immediately after surgery. During surgery flowtron anti-embolitic boots were used. Warfarin therapy was recommenced on the seventh postoperative day. Anaesthesia for Caesarean section was provided using a combined spinal epidural technique using a separate needle, separate interspace method. Postoperative pain was relieved by using a continuous epidural infusion, transcutaneous nerve stimulation and diclofenac. No new neurological problems arose despite the use of epidural analgesia in the presence of heparin anticoagulation. This method of providing anaesthesia and postoperative analgesia without the use of opioids in an anticoagulated, asthmatic, myotonic parturient has not been described elsewhere.

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

Fentanyl and pethidine are antagonists on muscarinic receptors in guinea-pig ileum

In order to evaluate the anticholinergic effect of fentanyl and pethidine, the influence of these drugs on the cumulative dose-response curves of carbacholine on the guinea-pig ileum has been investigated. Fentanyl and pethidine displaced the dose-response curve for carbacholine to the right in a parallel fashion, indicating competitive antagonism. Dissociation constants determined by an agonist EC versus antagonist plot were 0.22 mumol/l for fentanyl and 1.4 mumol/l for pethidine. It is concluded that during high-dose fentanyl anaesthesia, fentanyl may bind to muscarinic receptors and thereby produce a central anticholinergic syndrome. An additional finding was that the maximal response to carbacholine increased significantly when combined with pethidine.

Six months of shivering in a district general hospital

Of 2595 patients admitted to a recovery room in Derbyshire Royal Infirmary over a 6-month period, 164 (6.3%) shivered postoperatively. Data regarding the anaesthetic techniques to which these patients had been subjected were gathered from the Derby Anaesthetic Audit System. Subsequent analysis demonstrated the importance of a number of factors that led to shivering, including male gender, anaesthetic techniques involving spontaneous ventilation, and anticholinergic premedication. The administration of pethidine, alfentanil or morphine intra-operatively reduced the incidence of shivering postoperatively.