Safety of laryngeal mask airway and short-stay practice in office-based adenotonsillectomy

BACKGROUND

It is still disputed whether laryngeal mask airway (LMA) is safe and convenient for adenotonsillectomy, and whether these procedures can be safely undertaken in an office-based short-stay ambulatory setting. We report the result of this practice in 1126 consecutive children < 16 years of age.

METHODS

The patients received general anaesthesia with propofol and remifentanil. For analgesic prophylaxis, they received paracetamol, fentanyl and local anaesthetic administration. NSAIDs were given to patients weighing above 15 kg. A surgical technique with elevation, scissors and electrocoagulation was used. Post-operatively, the tonsillectomies were observed in the unit for at least 1.5 h and the adenoidectomies for at least 15-20 min.

RESULTS

Conversion from LMA to an endotracheal tube was carried out in six patients (0.5%), mostly due to airway leakage during ventilation. One patient had a pulmonary atelectasis and was re-intubated. No re-operation was needed in the clinic after surgery, and all patients, except for the one with atelectasis (0.1%), were discharged home as planned. In 122 patients answering a questionnaire, after discharge, two patients (1.6%) were admitted to hospital and re-operated due to bleeding; a further six patients (4.9%) were admitted for observation. In 25% of the patients, nausea and vomiting occurred after discharge, including 21% vomiting of swallowed blood during home travel. Only 5.6% reported significant post-discharge pain.

CONCLUSION

With a well-trained team, adenotonsillectomy on children can be carried out safely in an office-based setting with LMA and a short post-operative stay.

Fast-track surgery for bariatric laparoscopic gastric bypass with focus on anaesthesia and peri-operative care. Experience with 500 cases

BACKGROUND

Bariatric surgery for morbid obesity implies challenges in anaesthesiological handling. We report our experience from 500 consecutive patients during 3 years.

METHODS

The patients were due for laparoscopic Roux-en-Y gastric bypass and enteral bypass. Sleep was induced after pre-oxygenation with target control infusions (TCI) of remifentanil and propofol; vecuronium was supplied for facilitating endotracheal intubation. The propofol infusion was stopped and desflurane 3-6% was given for BIS-titrated anaesthetic maintenance together with remifentanil TCI. Antiemetic prophylaxis was supplied with intravenous (IV) droperidol, ondansetron and dexamethasone; post-operative pain prophylaxis was IV paracetamol, parecoxib and bupivacaine infiltration. The patients were extubated in the operating room and kept in the post-operative care unit for 3-4 h, being tested for a 20 m walk before discharge to the ward.

RESULTS

The procedure was uncomplicated peri-operatively in all 500 cases and in 497 patients (99.4%) post-operatively. Three patients had one complication, which resolved without sequelae: oesophageal rupture from gastric tubing, reoperation for anastomosis leakage and pneumonia. The mean duration of surgery was 57 min (range 37-91). The mean time from the start of anaesthesia until the start of surgery and time from the end of surgery until the end of anaesthesia were both significantly reduced throughout the study period, from 23 to 7.8 and 5.8 to 1.9 min, respectively (P<0.001). The mean total hospital stay was reduced from 3 days at start to 2 days in the end of the series (P<0.05).

CONCLUSION

Safe bariatric short-stay surgery is feasible with a dedicated anaesthesiological concept in an expert surgical team.

Comparison of etoricoxib vs. ketorolac in postoperative pain relief

BACKGROUND

COX-2 inhibitors have been claimed to have equal analgesic efficacy as non-selective nonsteroidal anti-inflammatory drugs, but this has been disputed in animal experiments.

METHODS

One hundred thirty-three women scheduled for ambulatory, laparoscopic gynaecological surgery were included in this randomised, double-blind study. Group E received 120 mg etoricoxib orally as premedication. Group K received 30 mg ketorolac i.v. after induction of anaesthesia. General anaesthesia was induced and maintained with propofol and remifentanil. Fentanyl 0.5 microg/kg i.v. and local wound anaesthesia was administered at the end of surgery. Postoperatively, the patients received fentanyl 0.5 microg/kg i.v. if visual analogue scale (VAS) >or=30 mm. Before discharge, Group K received 30 mg ketorolac i.v. Twenty-four hours postoperatively, Group E received 120 mg etoricoxib.

RESULTS

The first 4 h postoperatively, Group K required 83+/-65 microg and Group E required 123+/-91 microg fentanyl [mean (SD), P=0.004]. After 30 min VAS in Group K was 31.3+/-19.7 mm and 43.8+/-16.9 mm in Group E [mean (SD), P<0.001]. Discharge readiness was significantly shorter in Group K (222+/-40 min) compared with Group E (244+/-47 min) [mean (SD), P=0.004]. There were no differences in pain scores or rescue pain medication at 24 or 48 h postoperatively. Less nausea was observed in the 4-24-h period in Group E.

CONCLUSIONS

Thirty milligram ketorolac i.v. after induction of anaesthesia resulted in significantly less immediate pain and opioid consumption during the first 4 h postoperatively compared with 120 mg etoricoxib preoperatively.

Administration of fentanyl before remifentanil-based anaesthesia has no influence on post-operative pain or analgesic consumption

BACKGROUND

Remifentanil's short-acting analgesic effect and the potential of producing hyperalgesia is a challenge to post-operative pain control. This study investigated whether pre-treating the patients with fentanyl before remifentanil-based anaesthesia could reduce post-operative pain or analgesic consumption.

METHODS

One-hundred patients admitted for anterior cruciate ligament repair were included in a double-blind study. Propofol and remifentanil were used for general anaesthesia. Group Pre received fentanyl 1.5 microg/kg intravenously (IV) and Group Post placebo before the remifentanil infusion. At the end of surgery, Group Pre received 1.5 microg/kg and Group Post received 3.0 microg/kg. Patient-controlled analgesia with fentanyl was used as analgesic rescue medication during the first 4 h post-operatively. Oxycodone 5 mg orally was taken as needed during the subsequent 4-24-h period.

RESULTS

A mean dose of remifentanil 0.43 microg/kg/min was used for 90 min during surgery in both groups. There were no differences in the verbal rate scale (VRS) score or need of rescue analgesic medication between the groups during the first 4 h. Group Post had significantly less pain in the 4-24-h period after surgery, with a median VRS score of 'slight pain' vs. 'moderate pain' in Group Pre (P<0.05). The oxycodone consumption was similar in both groups.

CONCLUSION

Pre-treatment with fentanyl 1.5 microg/kg IV yielded no reduction in post-operative pain or analgesic consumption after 90 min of remifentanil-based anaesthesia with 0.43 microg/kg/min of remifentanil.

The Prolonged Postoperative Analgesic Effect When Dexamethasone Is Added to a Nonsteroidal Antiinflammatory Drug (Rofecoxib) Before Breast Surgery

BACKGROUND

Glucocorticoids provide analgesia. In this study, we evaluated the effects of adding dexamethasone to a multimodal postoperative analgesic regimen, including a long-acting nonsteroidal antiinflammatory drug.

METHODS

One-hundred patients admitted for ambulatory breast cancer surgery were studied. They received paracetamol 2 g and rofecoxib 50 mg orally 1 h before start of general anesthesia with propofol and remifentanil. The patients were then randomized to receive, in a double-blind manner, either dexamethasone 16 mg IV or placebo. Both groups received fentanyl 1 mug/kg IV and 20-40 mL bupivacaine 2.5 mg/mL wound infiltration before the end of surgery.

RESULTS

There was no difference in pain scores or rescue medication between the groups during the first 4 h after surgery. After discharge, the median pain score during coughing or shoulder movement was 3 on a 0-10 scale in patients receiving placebo, and 1 in the patients receiving dexamethasone, which did not reach statistical significance (P = 0.06). From 24 to 72 h, the median pain with coughing or shoulder movement in patients receiving placebo was 2, and 1 in patients receiving dexamethasone, which did reach statistical significance (P < 0.05). Forty percent of patients receiving dexamethasone were pain free from 4 to 24 h, compared with 24% of patients receiving placebo, a difference that did not reach statistical significance (P = 0.09). Similarly, 46% of patients receiving dexamethasone were pain free from 24 to 72 h, compared with 28% of patients receiving placebo (P = 0.06). More patients had slept poorly on the first night in the dexamethasone group than in the control group, 68% vs 44%, (P < 0.05).

CONCLUSIONS

Dexamethasone 16 mg provides prolonged postoperative analgesia from 24 to 72 h after surgery when added to a multimodal regimen including nonsteroidal antiinflammatory drug (rofecoxib).

Analgesic and antiemetic effect of ketorolac vs. betamethasone or dexamethasone after ambulatory surgery

BACKGROUND

Glucocorticoids are known to provide slower onset and more prolonged duration of analgesic effect than ketorolac. In the present study, we wanted to evaluate the effect over time from a single dose of either intravenous (i.v.) dexamethasone or an intramuscular (i.m.) depot formulation of betamethasone compared with i.v. ketorolac.

MATERIALS AND METHODS

One hundred and seventy-nine patients admitted for mixed ambulatory surgery were included in the study. After induction of general i.v. anaesthesia, the patients were randomized to receive double-blindly either dexamethasone 4 mg i.v. (Group D) or betamethasone depot formulation 12 mg i.m. (Group B) or ketorolac 30 mg i.v. (Group K). Fentanyl was used for rescue analgesic medication in the post-operative care unit (PACU) and codeine with paracetamol after discharge, for a study period of 3 days.

RESULTS

There was significantly less post-operative pain in the ketorolac group during the stay in the unit (88% with minor or less pain in Group K vs. 74% and 67% in Groups D and B, respectively, P < 0.05), significantly less need for rescue medication (P < 0.05) and significantly less nausea or vomiting (12% in Group K vs. 30% in the other groups pooled, P < 0.05). The ketorolac patients were significantly faster for ready discharge, median 165 min vs. 192 min and 203 min in Groups D and B, respectively (P < 0.01). There were no differences between the groups in perceived pain, nausea, vomiting or rescue analgesic consumption in the 4- to 72-h period.

CONCLUSION

Dexamethasone 4 mg or bethamethasone 12 mg did not provide prolonged post-operative analgesic effect compared with ketorolac 30 mg, which was superior for analgesia and antiemesis in the PACU.

Can the cerebral state monitor replace the bispectral index in monitoring hypnotic effect during propofol/remifentanil anaesthesia?

BACKGROUND

In 2004, the cerebral state monitor, CSM, was launched as a low-cost alternative to the bispectral index, BIS, for monitoring depth of sleep during anaesthesia. We tested whether the two monitors would reflect hypnosis equally during propofol/remifentanil anaesthesia.

METHODS

During laparoscopy or breast/surface surgery, 55 non-paralyzed patients were monitored simultaneously with the BIS and the CSM. Trend curves for the indexes [BIS and cerebral state index (CSI)] were compared for congruence. The difference between the two indexes for the entire course was quantified, and the ability of the two monitors to separate awake from asleep during induction was described.

RESULTS

In the majority of the patients, 87%, there was a good fit between the indexes. There were major deviations in seven patients, in whom CSI indicated that the patients were awake during parts of the course despite clinical sleep, correctly identified with the BIS. Both indexes separated awake from asleep during induction in the individual patient, but the overlap in values between patients was more pronounced for CSI.

CONCLUSION

CSM and BIS show some important differences in measuring hypnotic state during clinical propofol/remifentanil anaesthesia.

Does esomeprazole prevent post-operative nausea and vomiting?

BACKGROUND

Esomeprazole is a potent proton pump inhibitor (PPI), reducing acid production as well as gastric juice volume. This study evaluated the possible beneficial effect of esomeprazole on reducing post-operative nausea and vomiting (PONV).

METHODS

Patients undergoing laparoscopic or open gynaecological surgery, or laparoscopic cholecystectomy were randomized to receive three peri-operative doses double blindly of either esomeprazole 40 mg or placebo, given intravenously or orally. All patients were given a standardized anaesthesia regimen including fentanyl and sevoflurane/nitrous oxide.

RESULTS

The study population consisted of 284 patients. Demographic data and known PONV risk factors were similar for the two treatment groups. PONV was observed in 77% of patients on esomeprazole vs. 81% on placebo (NS) and rescue antiemetic medication was needed in 56% vs. 53%, respectively (NS). The proportion of patients that vomited during 0-24 h was lower on esomeprazole than placebo (38% vs. 49%; NS), and the mean amount of vomit was significantly lower (52 vs. 86 g; P < 0.05). The use of neostigmine, use of opioids and type of surgery were significant risk factors for PONV (P < 0.05). The 24-h incidence of PONV was 63% after laparoscopic gynaecology, 80% after laparoscopic cholecystectomy and 88% after open gynaecological laparotomy, whereas laparoscopic cholecystectomy had the lowest risk when corrected for other risk factors of PONV.

CONCLUSION

Esomeprazole had no clinically relevant effect on the overall 24-h incidence of PONV. However, esomeprazole significantly reduced the total amount of vomit during 24-h post-operatively. This may be of value in patients with an increased risk of pulmonary aspiration.

[Laparoscopic gastric bypass surgery in extreme overweight at a private hospital]

BACKGROUND

Laparoscopic gastric bypass surgery leads to significant weight loss and reduced morbidity in patients with severe obesity. The technique was introduced at the private Aleris hospital the autumn 2005. We here present the method and results from our initial experience.

MATERIAL AND METHODS

Inclusion criteria were BMI > 40 kg/m2 or BMI 35-39,9 kg/m2 , with obesity-related co-morbidity for more than 5 years and insufficient effect of conservative treatment. The first 121 (103 women) consecutive patients who underwent gastric bypass surgery at Aleris Hospital were included. Characteristics were; mean age 40 years (18-68), mean preoperative body weight 134 kg (91-211) and BMI 44 m/kg 2 (35-64). Serious complications or major morbidity were defined as anastomosis- or intestinal leakage and bleeding requiring surgical treatment.

RESULTS

No deaths or major morbidity was observed the first 30 days after surgery. One patient underwent successful surgery of a perforated ulcer localized distally to the gastro-jejunal anastomoses 3 months p.o. Mean operating time was 62 min (40-124) for patients who underwent isolated laparoscopic bypass. The mean hospitalisation time was 2.9 days (2-6).

CONCLUSION

Our results demonstrate that bariatric surgery can be established successfully with a low rate of perioperative complications. We believe that thorough planning and experienced bariatric surgeons contribute to our favourable results. .

Skin conductance or entropy for detection of non-noxious stimulation during different clinical levels of sedation

BACKGROUND

State entropy (SE) measures electroencephalographic signals, whereas response entropy (RE) also includes frontal electromyographic activity. In the presence of electromyographic activity, the RE index is larger than the SE index, the difference being denoted as RE-Delta (RE-Delta= RE - SE). Skin conductance (SC) may be expressed by a slow reacting variable, the mean SC level, the derivate of the mean SC level (D-SC), the number of SC fluctuations (NSCF) or the amplitude of the SC fluctuations (ASCF), which directly shows skin sympathetic nerve activity. The goal of this study was to evaluate whether these SC and entropy variables could differentiate between the responses obtained to load sound stimuli at different sedation levels before the induction of general anaesthesia.

METHODS

Twenty women scheduled for gynaecological laparotomy were studied. The modified observer's assessment of alertness sedation (OAAS) was used to classify the patients' hypnotic levels. White sounds (98 dB) were given at OAAS level 5 without propofol, at OAAS levels 4-3 and 3-2 with propofol and at OAAS levels 3-2 and < 2 with propofol and remifentanil.

RESULTS

RE and SE showed a steady decline from OAAS level 5 to level < 2 (P < 0.01). RE-Delta did not discriminate between any of the OAAS levels (P= NS). The mean SC level discriminated between OAAS levels 4-3 to < 2 (P < 0.01). D-SC discriminated between all the different OAAS levels (P < 0.01). NSCF discriminated between OAAS levels 5 to 3-2 (P < 0.05), but did not discriminate at OAAS level 3-2 between propofol alone or combined with remifentanil, or between OAAS level 3-2 and < 2. ASCF differentiated between OAAS levels 5 and 4 (P < 0.001) and OAAS levels 3-2 and < 2 (P < 0.05) only.

CONCLUSION

RE, SE and D-SC showed a similar discrimination between sound responses at the different sedation levels.

Comparison of skin conductance with entropy during intubation, tetanic stimulation and emergence from general anaesthesia

BACKGROUND

The number of skin conductance fluctuations (NSCF) expresses sympathetic skin nerve activity. The response entropy (RE) measures electromyographic and electroencephalographic activity in the forehead. The state entropy (SE) measures mainly electroencephalographic activity. When the suppression of frontal muscular activity is complete, RE is equal to SE. RE-Delta is defined as SE minus RE. The purposes of this study were to examine whether NSCF and RE-Delta correlate with signs of clinical stress during intubation and tetanic noxious stimulation and to elucidate how rapidly and accurately entropy and NSCF react during emergence from general anaesthesia.

METHODS

Twenty women scheduled for gynaecological laparotomy were studied. During intubation in remifentanil and propofol general anaesthesia, NSCF and RE-Delta were correlated with the clinical stress score. After a wash-out period, two series of tetanic stimuli were given, the first with (R+) and the second without (R-) remifentanil infusion. The tetanic pre-stimuli periods were compared with the tetanic post-stimuli periods, and R+ was compared with R-. During emergence, the responses of entropy and skin conductance were related to the time of extubation.

RESULTS

NSCF correlated well with the clinical stress score during intubation (r(2)= 0.73, P < 0.0005). RE-Delta showed a weaker correlation (r(2)= 0.33, P= 0.007). During tetanic stimuli, the NSCF pre-stimuli level was lower than the post-stimuli level (P < 0.001), and the NSCF R+ response was lower than the NSCF R- response (P= 0.002). RE-Delta did not show similar differences. During emergence, RE reacted before NSCF and SE (P= 0.003).

CONCLUSION

NSCF was better than RE-Delta for the measurement of clinical stress during intubation, and was sensitive to tetanic stimuli at different opioid analgesic levels, by contrast with RE-Delta. Both modalities were able to predict emergence at the end of anaesthesia, but RE was more rapid.

Similar onset time of 2-chloroprocaine and lidocaine + epinephrine for epidural anesthesia for elective Cesarean section

BACKGROUND

The use of regional anesthesia for elective Cesarean section has been demonstrated to be safe for both the mother and new-born. In parturients with an epidural catheter placed previously for labor analgesia, extension of the epidural block may be the preferred option, provided that adequate speed of onset and adequate surgical anesthesia are obtained. We therefore performed a prospective, randomized, double-blind trial to examine the speed of onset and anesthetic quality of 2-chloroprocaine vs. a solution of lidocaine with one additive, epinephrine 5 microg/ml.

METHODS

Forty ASA I patients, scheduled for elective Cesarean section, were randomly assigned to two groups: the 2-chloroprocaine group received 2-chloroprocaine 30 mg/ml and the lidocaine group received the same amount (ml) of lidocaine 20 mg/ml with 5 microg/ml epinephrine. The speed of onset was defined as the time taken to loss of cold sensation from 70% ethanol application at thoracic dermatome level 5 (Th5).

RESULTS

The time to achieve loss of cold sensation at Th5 was similar in both groups: median of 8 min (range, 4-13 min) in the 2-chloroprocaine group vs. 5 min (range, 2-22 min) in the lidocaine group (NS). Epidural anesthesia was successful for surgery in all but one patient (lidocaine group). There was no significant difference in the need for supplemental intravenous alfentanil between the two groups: 30% vs. 20% of patients in the 2-chloroprocaine and lidocaine groups, respectively; the pain scores (visual analog scale) were also similar. Intra-operative complications occurred with similar frequency, and none was serious. In the patients in the 2-chloroprocaine group, 11 (55%) had episodes of systolic blood pressure less than 90 mmHg vs. 15 (75%) in the lidocaine group (NS).

CONCLUSION

Both 2-chloroprocaine and lidocaine have a rapid onset of effect and are suitable local anesthetic agents for Cesarean section. In view of the time taken for preparation and the potential for logistic problems when an additive is used, a pre-prepared solution, such as 2-chloroprocaine, may be preferred.

Why do women wake up faster than men from propofol anaesthesia?

BACKGROUND

It has repeatedly been shown that female patients wake up faster from propofol anaesthesia than male patients. The reason for this is not clear. It is possible that female patients have a more rapid decline in plasma propofol concentration after termination of an infusion, or there could be gender differences in the sensitivity to propofol, making women wake up at higher concentrations. We tested the hypothesis that women wake up faster because of a more rapid decline in plasma propofol.

METHODS

Sixty adult patients (30 female and 30 male; ASA I or II) undergoing lower limb surgery under regional anaesthesia, were enrolled in an open study. Propofol was given as the only hypnotic drug, administered by the plasma target control system (TCI) Diprifusor, titrated to bispectral index (BIS) values of 40-60. Blood samples for propofol measurements were taken just before the propofol infusion was stopped and when the patients woke up.

RESULTS

The female patients woke up faster than the male patients (5.6 vs 8.2 min, P=0.003). The plasma propofol concentration declined more rapidly in the women (P=0.02). An additional significant finding was that the TCI algorithm had a better fit for the women than for the men, with a median prediction error (MDPE) of 2% in the female patients compared with 40% in the male patients (P<0.001). At emergence the men had a significantly higher measured propofol concentration than the women (P=0.05).

CONCLUSION

The female patients had a more rapid decline in plasma propofol at the end of infusion. Gender differences in pharmacokinetics could explain the faster emergence for female patients after propofol anaesthesia, and gender differences in propofol sensitivity may also be present.

Is peri-operative cortisol secretion related to post-operative cognitive dysfunction?

BACKGROUND

The pattern of cortisol secretion is influenced by surgery. As cortisol can adversely affect neuronal function, this may be an important factor in the development of post-operative cognitive dysfunction (POCD). We hypothesized that the incidence of POCD would be related to changes in cortisol level.

METHODS

We studied 187 patients aged over 60 years undergoing major non-cardiac surgery with general or regional anaesthesia. Saliva cortisol levels were measured pre-operatively and at 1 day, 7 days and 3 months post-operatively in the morning (08.00 h) and in the afternoon (16.00 h) using salivettes. Cognitive function was assessed pre-operatively, on day 7 and at 3 months using four neuropsychological tests. POCD was defined as a combined Z score of greater than 1.96.

RESULTS

After surgery, salivary cortisol concentrations increased significantly. POCD was detected in 18.8% of subjects at 1 week and in 15.2% after 3 months. The pre-operative ratios between the morning and afternoon cortisol concentrations (am/pm ratios) were 2.8 and 2.7 in patients with POCD at 1 week vs. those without POCD at 1 week, respectively. The am/pm ratios decreased significantly post-operatively to 1.9 and 1.6 at 1 week, respectively (P = 0.02 for both). In an analysis considering all am/pm ratios, it was found that the persistent flattening in am/pm ratio was significantly related to POCD at 1 week.

CONCLUSION

The pattern of diurnal variation in cortisol level was significantly related to POCD. Thus, circadian rhythm disturbance or metabolic endocrine stress could be an important mechanism in the development of cognitive dysfunction after major surgery.

Pre-operative fasting guidelines: an update

Liberal pre-operative fasting routines have been implemented in most countries. In general, clear fluids are allowed up to 2 h before anaesthesia, and light meals up to 6 h. The same recommendations apply for children and pregnant women not in labour. In children <6 months, most recommendations now allow breast- or formula milk feeding up to 4 h before anaesthesia. Recently, the concept of pre-operative oral nutrition using a special carbohydrate-rich beverage has also gained support and been shown not to increase gastric fluid volume or acidity. Based on the available literature, our Task Force has produced new consensus-based Scandinavian guidelines for pre-operative fasting. What is still not clear is to what extent the new liberal fasting routines should apply to patients with functional dyspepsia or systematic diseases such as diabetes mellitus. Other still controversial areas include the need for and effect of fasting in emergency patients, women in labour and in association with procedures done under 'deep sedation'. We think more research on the effect of various fasting regimes in subpopulations of patients is needed before we can move one step further towards completely evidence-based pre-operative fasting guidelines.

McArdle's disease and anaesthesia: case reports. Review of potential problems and association with malignant hyperthermia

BACKGROUND

McArdle's disease of isolated deficiency in glycogen degradation in skeletal muscles has the potential of creating perioperative anaesthesiological problems; such as hypoglycaemia, rhabdomyolysis, myoglobinuria, acute renal failure and possibly malignant hyperthermia.

METHODS

Eight patients with McArdle's disease were asked about previous surgery, anaesthesia and perioperative problems, and available hospital records were reviewed. Existing literature was reviewed for reports on McArdle's disease and anaesthesia.

RESULTS

The eight patients had 35 anaesthesias (23 general anaesthesias, three regional anaesthesias and nine local anaesthesias). Perioperative problems of a non-specific nature were mentioned in three cases of general anaesthesia: two with postoperative nausea/vomiting, and one with an episode of tachycardia and low blood pressure. Three patients were tested for malignant hyperthermia (MH) using the in vitro contracture test (IVCT); two of them with a positive result. The literature search revealed seven case reports of McArdle's disease and anaesthesia. Apart from one report of hyperthermia, pulmonary oedema and rhabdomyolysis; probably not associated with MH, no problems were encountered from the literature search.

CONCLUSION

McArdle's disease does not seem to cause severe perioperative problems in routine anaesthetic care. However, measures for preventing muscle ischaemia and rhabdomyolysis should be kept in mind, as well as the potential for these patients to develop postoperative fatigue, myoglobinuria and renal failure. Although no clinical association with malignant hyperthermia has been established, many of these patients can have a positive in vitro contracture test, and simple prophylactic measures, as with malignant hyperthermia, may be recommended if otherwise not contraindicated.

Palmar skin conductance compared to a developed stress score and to noxious and awakening stimuli on patients in anaesthesia

BACKGROUND

The number of fluctuations in the skin conductance per s (NFSC) as a measure of the sympathetic nervous system may be a tool for monitoring physiological stress during surgery and general anaesthesia. The purpose of this study was to find the sensitivity and specificity of the NFSC when compared to a peroperative clinical stress score. Moreover, different patterns of skin conductance responses were compared with the BIS score to find out if the mean level of skin conductance (SC) and NFSC monitoring could differentiate between awakening and noxious stimuli.

METHODS

Fourteen patients were studied during stressful or non-stressful registration periods. During each registration period, the NFSC was compared to a five-point clinical stress score (CSS) (systolic blood pressure >130 mmHg, cough, tears, EMG in the forehead >50 or movements) and BIS score.

RESULTS

The NFSC and the CSS both indicated physiological stress at 12 registrations and no stress at 186 registrations. The NFSC indicated physiological stress without signs of clinical stress (CSS = 0) in 28 registrations, whereas signs of clinical stress (CSS > 0) were indicated on two occasions without signs of stress in the NFSC. The sensitivity of the NFSC when compared to the CSS was 86% and the specificity was 86%. Moreover, in all situations (n = 16) where NFSC indicated stress and the BIS score >50, the SC increased. This was different from situations (n = 13) where NFSC indicated stress and the BIS score <50, then the SC did not increase (P < 0.001).

CONCLUSION

The NFSC is sensitive to clinical stress during surgical stimulation. Moreover, the combined use of SC and NFSC may have a potential to differentiate between situations of stress due to inadequate hypnotic effect vs. inadequate analgesic effect.