Transdermal nicotine increases heart rate after endotracheal intubation.

Transdermal nicotine reduces perioperative withdrawal symptoms when smoking is forbidden. We evaluated the influence of a transdermal nicotine system on cardiovascular response after endotracheal intubation. The study design was prospective, randomized, double-blind and placebo- controlled. Sixty healthy smokers scheduled for minor surgery under general anesthesia were divided into two groups. The first group received a 21 mg/day transdermal nicotine system while the second group received a placebo transdermal system. After induction with standardized doses of fentanyl, thiopental and atracurium, the patients were intubated immediately when EMG-response decreased to 10% of the initial control. Heart rate and noninvasive arterial pressures were recorded 1 min and 5 min after intubation. The transdermal nicotine system significantly increased heart rate compared with the control group without nicotine substitution. Since the transdermal nicotine system increases heart rate it should not be used if tachycardia is potentially dangerous, such as in patients with ischemic heart disease.

Suxamethonium-induced rhabdomyolysis in a healthy middle-aged man.

A 43-year-old man developed rhabdomyolysis after uvulo- palatopharyngoplasty. After induction with thiopentone and suxamethonium the anesthesia was maintained with halothane. The patient responded to treatment and made an uneventful recovery. In earlier reports of rhabdomyolysis after general anaesthesia with halothane and suxamethonium almost all the patients had malignant hyperthermia (MH) or muscular dystrophy. About 50% of malignant hyperthermia patients carry a mutation in the RYR1 gene. Our patient did not have mutations in the four MH-associated genes tested, but the total amount of different mutations is by now about twenty. Therefore, despite these negative tests rhabdomyolysis may be a sign of subclinical malignant hyperthermia which cannot be ruled out by our investigations. This rare case of rhabdomyolysis in a healthy man suggests careful monitoring of the patient when-ever suxamethonium is used.

Edrophonium is better than neostigmine to antagonize residual vecuronium induced neuromuscular block.

Edrophonium (EDR) has the advantages of a quick onset of action and reduced cholinergic effects compared to neostigmine (NST) when they are used to antagonize neuromuscular block (NMB). There are few studies about antagonism of very weak residual NMB. Therefore we compared hemodynamic stability, train-of-four (TOF) characteristics and reversal time (time from administration of antagonists to train-of-four-ratio (TR) at least 0.70) of EDR 0.5 mg kg-1 + atropine (ATR) 0.007 mg kg-1 to NST 0.04 mg kg-1 + glycopyrrolate (GLY) 0.008 mg kg-1 when they were used to antagonize a residual vecuronium (VEC)-induced NMB (T1 25-75%). The NMB was monitored in 64 patients using the evoked electromyogram of the hypothenar muscle of the hand. An adequate antagonism was defined as a TR of 0.70 or higher. Heart rate was significantly higher in NST+GLY group 2 min after administration of the antagonists in comparison with the EDR+ATR group. The advantages of EDR (higher T1, TR and percentage of patients with an adequate recovery) were obvious during the first 5 min of reversal time. Therefore we conclude, that under the conditions described in the present study, EDR antagonizes residual VEC induced NMB faster than NST.

Etoricoxib pre-medication for post-operative pain after laparoscopic cholecystectomy.

BACKGROUND: Etoricoxib alleviates and prevents acute pain. The hypothesis of our study was that the pre-operative use of etoricoxib would reduce the post-operative need for additional pain treatment. METHODS: In this double-blind, randomized and active placebo-controlled study, 75 patients were pre-medicated 1.5 h before elective laparoscopic cholecystectomy with 120 mg of etoricoxib (E120 group), the same dose of etoricoxib combined with 1 g of paracetamol (E + P group) or placebo (Pla group). To alleviate post-operative pain, a patient-controlled analgesia (PCA) device was programmed to deliver 50 microg of fentanyl intravenously (lockout time, 5 min). The pain intensity and nausea were assessed using a visual analogue scale (VAS). The number of patients with post-operative nausea and vomiting was recorded. Blood loss was compared between the groups. Because the operations are almost blood-less, the operation time was also recorded to compare the possible effect on bleeding time. RESULTS: Pre-medication with etoricoxib or etoricoxib plus paracetamol had a statistically significant fentanyl-sparing effect 2-20 h post-operatively compared with placebo (P = 0.001). No significant differences were demonstrated in fentanyl-sparing effect between the E120 and E + P groups. No significant differences in pain intensity were found between the three study groups. No significant differences were observed between the groups with regard to nausea, blood loss, duration of anaesthesia or duration of surgery. CONCLUSION: Etoricoxib is suitable for pre-medication before laparoscopic cholecystectomy as it reduces the need for post-operative opioids. Opioid-related side-effects, however, were not reduced in the present study, despite the observed opioid-sparing effect of etoricoxib and combined etoricoxib and paracetamol.

Lack of analgesic effect of parecoxib following laparoscopic cholecystectomy.

BACKGROUND: The cyclo-oxygenase-2 inhibitor, parecoxib, can be administered parenterally. The recommended dose for post-operative use is 40 mg twice daily, which may not be the appropriate dose for the treatment of visceral pain. We studied the effect of a single dose of parecoxib of either 40 or 80 mg in laparoscopic cholecystectomy, and its effect on opioid-induced side-effects. METHODS: Seventy-three patients scheduled for elective laparoscopic cholecystectomy were enrolled in this prospective, randomized, double-blind study. Patients were randomized into three groups: a placebo-treated control group, a 40-mg parecoxib-treated group (P40) and an 80-mg parecoxib-treated group (P80). We recorded the cumulative fentanyl consumption during the first 20 h post-operatively by patient-controlled analgesia equipment, the pain scores during rest, coughing and mobilization (visual analogue scale, 0-10), the worst pain during the first 2 h post-operatively and in the following 18 h, and the side-effects by questionnaire. RESULTS: No significant differences in fentanyl consumption between the three groups could be detected. The worst pain experienced between 2 and 20 h post-operatively on the ward was significantly lower in the P80 group than in the control group. CONCLUSION: The recommended dose of parecoxib, 40 mg, is not effective for the treatment of pain during the early post-operative period after laparoscopic cholecystectomy. Doubling the dose to 80 mg seems to improve the results.

Gordon syndrome and succinylcholine.

We present a case of 6-year-old boy who developed severe hyperkalaemia and ventricular tachycardia after administration of succinylcholine. Ventricular tachycardia was defibrillated and Gordon syndrome, which was diagnosed subsequently, was treated successfully. Paediatric patients with underlying metabolic disorders such as Gordon syndrome are at high risk of developing severe hyperkalaemia after succinylcholine administration.

Neuromuscular blocking characteristics of vecuronium after tubocurarine-induced "fade". An experimental double-blind clinical study.

OBJECTIVE: The fade in train-of-four (TOF) monitoring is considered to be due to blocking of the prejunctional nicotinic acetylcholine receptors (AchRs). During onset of the neuromuscular block (NMB) tubocurarine (TC) causes more fade in the TOF responses than vecuronium (VEC). Therefore we wanted to investigate whether onset or duration of action of VEC or TC would be improved with a priming dose of an agent with different prejunctional activity. METHODS: The rates of NMB were measured following priming doses of 0.15 mg x kg(-1) of TC and 0.015 mg x kg(-1) of VEC with 6 min priming time. The individual time course of action of 0.6 mg x kg(-1) of TC (1.13 x ED 95) and 0.1-0.2 mg x kg(-1) of VEC (1.75-3.5 x ED95) were examined with a priming dose of the same agent or the other agent, by measurement of changes in the evoked compound EMG from the hypothenar muscle. RESULTS: Priming doses of TC decreased mean TOF ratio to 67% [95% confidence interval (CI) = 56-78] during priming time, which was significantly lower than after priming with VEC 87% (76-97; P < 0.001). Despite the higher TOF ratio, the priming dose of VEC accelerated the onset time of intubation dose of TC more than the priming dose of TC (P = 0.0018). Priming with TC prolonged the duration of VEC-induced NMB by 35-70 min compared with priming with VEC, which means that a small priming dose of TC changes VEC from a muscle relaxant with intermediate action to a long-acting agent. CONCLUSION: Priming with TC caused a lower TOF ratio; however, priming with TC did not accelerate the onset time of either agent as much as priming with VEC. It appears that potentiation of NMB after combination of VEC and TC is not dependent on "fade" receptors.

Does monitoring of post-tetanic count prevent alarms of airway pressure or visible muscle activity during intratracheal jet ventilation? A prospective study with five different neuromuscular blocking agents.

OBJECTIVE: Profound neuromuscular block (NMB) quantified by post-tetanic count (PTC) may prevent all muscle activity during anesthesia. We studied whether monitoring of PTC prevents airway pressure alarms or visible movements of the vocal cords and the abdomen during endolaryngeal procedures (ELPs). METHODS: In this prospective, double blind, study 50 healthy (ASA 1-3) patients scheduled for ELPs were randomized into five groups: atracurium, mivacurium, rocuronium, vecuronium and succinylcholine. During alfentanil-propofol anaesthesia, profound NMB was controlled by monitoring the PTC (target level PTC 0-2, 50 Hz tetanic stimulation) of the adductor pollicis muscle. The muscle relaxants were administered using bolus dosing in all groups but in the succinylcholine group. The early signs of recovery of NMB to be observed were: 1) airway pressure alarms, 2) movements of vocal cords on the laryngeal video monitor and 3) movements of the abdomen. The inference was based on 90% confidence interval tests. RESULTS: During 50 ELP:s following signs of early recovery of NMB were recognized: 2 alarms of airway pressure, 16 laryngeal movements and 11 movements of the abdomen. The proportion of airway pressure alarms was significantly lower than proportion of all detectable movements (95% confidence interval analysis). Twelve of the movements were recorded at PTC zero level. The signs of early recovery of NMB were detected in all groups. CONCLUSIONS: PTC-monitoring following 50 Hz stimulation does not ensure total inactivity of muscles during alfentanil-propofol anesthesia, regardless which relaxant has been chosen. During ELPs, simultaneous observation of the vocal cords and the abdomen is more sensitive in detecting early recovery of NMB compared to our method of airway pressure monitoring.

Does abstinence from smoking or a transdermal nicotine system influence atracurium-induced neuromuscular block?

UNLABELLED: The purpose of the present study was to investigate the interaction of chronic smoking and the actions of atracurium (ATR). Twenty nonsmokers (NON-SMOK) were compared with 80 smokers, who were randomized into three groups: 30 patients received 21 mg/d transdermal nicotine system > or = 10 h before fentanyl/thiopental/N2O/O2/isoflurane anesthesia (TD-NICO), whereas the abstinent group received a placebo transdermal system (ABST, n = 30). The TD-NICO and ABST groups refrained from smoking for at least 10 h before the induction of anesthesia. A third group was allowed to smoke until 1-3 h before anesthesia (SMOK, n = 20). Neuromuscular block was monitored using a Relaxograph (Datex, Helsinki, Finland). The electromyographic response was recorded from the first dorsal interosseus muscle of the hand. The inspiratory isoflurane concentration was kept constant at 0.7 vol% in all patients. After an initial bolus dose of 0.5 mg/kg ATR, no significant difference was observed among the groups regarding onset time and maximal neuromuscular block. In Group ABST, the duration of block until 25% recovery of T1 was 48.2 +/- 10.1 min, which was significantly longer (analysis of variance post hoc tests) than in Groups TD-NICO, SMOK, and NON-SMOK (42.7 +/- 7.1, 41.4 +/- 10.4, and 42.8 +/- 7.3 min, respectively). The maintenance dose of ATR in Group ABST (0.23 +/- 0.03 mg x kg(-1) x h(-1)) was smaller than in Groups TD-NICO, SMOK, and NON-SMOK (0.30 +/- 0.07, 0.32 +/- 0.06, and 0.32 +/- 0.05 mg x kg(-1) x h(-1), respectively). We conclude that abstinence from smoking increases the duration of ATR-induced neuromuscular block and reduces the maintenance dose of ATR in smokers. Perioperative use of a transdermal nicotine system prevents these abstinence-induced changes in duration and maintenance-dose. IMPLICATIONS: The purpose of the present study was to investigate the interaction of chronic smoking and atracurium. Smokers who refrain from smoking for > 10 h require a smaller maintenance dose of atracurium than nonsmokers. However, using a transdermal nicotine system prevents the decrease in maintenance dose during abstinence.

Neurologic sequelae after caesarean section.

BACKGROUND: Because pregnancy increases the sensitivity of nervous tissue to local anaesthetics, pregnant patients may be at higher risk of developing neurologic deficits after spinal block than non-pregnant patients. Therefore, we evaluated prospectively the incidence and type of neurologic symptoms after spinal anaesthesia with hyperbaric bupivacaine for caesarean section. METHODS: In this prospective follow-up study we recorded neurologic complications during anaesthesia and postoperatively until discharge from the hospital of 219 patients, who underwent caesarean section under spinal anaesthesia with hyperbaric bupivacaine (5 mg/ml, mean 13 mg). The patients filled in a questionnaire on the first and fifth postoperative days. In the case of complaints typical of neurologic symptoms they were checked first by the anaesthesiologist and, in the case of persistent symptoms, afterwards additionally by a neurologist. RESULTS: Twenty-six of 219 patients were not included in the further evaluation because of incomplete return of their questionnaires. Seventeen mothers (8.8%) complained of transient neurologic symptoms (TNSs), lasting mostly 1-2 days, in the buttocks and/or legs during the first three postoperative days. Eleven patients (5.7%) complained of postdural puncture headache. Two patients (emergency caesarean section because of protracted labour in one and elective caesarean section because of previous caesarean section in the other) complained of persisting pain or sensory abnormalities. Neither of them felt paraesthesia during lumbar puncture. CONCLUSION: Women after caesarean section under a spinal block seem to suffer more often from TNSs than non-pregnant women. The conclusions are, however, uncertain since we had no control group operated on under other than spinal anaesthesia. The persisting neurologic symptoms in two patients might also be due to the obstetric procedure itself. To find out about the validity and possible underlying causes of our results, we need randomised studies with control groups receiving epidural or general anaesthesia.

The costs of intense neuromuscular block for anesthesia during endolaryngeal procedures due to waiting time.

UNLABELLED: The goal of this double-blinded, prospective study was to compare the costs incurred by waiting time of intense neuromuscular block while posttetanic count (PTC) was maintained at 0-2 during jet ventilation. Fifty patients were randomized into five groups to receive atracurium (ATR), mivacurium (MIV), rocuronium (ROC), vecuronium (VEC), and succinylcholine (SUCC). PTC < or =2 was maintained until completion of laryngomicroscopy by administering additional doses of relaxants or by adjusting the speed of the infusion of SUCC. We compared waiting time, i.e., onset time and recovery time, and costs of intense neuromuscular block. The expenses due to waiting time were calculated based on the average costs in the otorhinolaryngological operating room in Tampere University Hospital: FIM 40 (approximately $8) per minute in 1997. MIV and SUCC differ favorably from ATR, ROC, and VEC when waiting time and costs are concerned. The recovery times with MIV and SUCC were considerably shorter than those with ATR, ROC, and VEC (P < 0.001 in all pairwise comparisons). Using the muscle relaxant with the longest waiting time instead of that with the shortest waiting time (difference 21.8 min) cost more than FIM 800 (approximately $160) extra per patient. IMPLICATIONS: In this randomized, double-blinded, prospective study, we evaluated the costs of intense neuromuscular block due to waiting time. Succinylcholine and mivacurium are the most economical muscle relaxants to use when intense neuromuscular block is mandatory. Using intermediate-acting muscle relaxants results in unduly prolonged recovery time and extra costs.