Comparison of intubating conditions after rocuronium and suxamethonium following "rapid-sequence induction" with thiopentone in elective cases

Background : Rocuronium (Org 9426) was shown to have the fastest onset of action of all currently available non-depolarizing neuromuscular blocking drugs and to provide intubating conditions similar to those of suxamethonium 60 to 90 s after administration. We compared the intubating conditions after rocuronium and suxamethonium following rapid-sequence induction of anaesthesia.
Methods : Fifty unpremedicated patients of ASA physical status I or II, scheduled for elective surgery were studied. Anaesthesia was induced with thiopentone 6 mg kg^-1 followed randomly by suxamethonium 1 mg kg^-1 or rocuronium 0.6 mg kg^-1 and, 45 s later, intubation was commenced. Muscle fasciculations, intubating conditions and intubation time, haemodynamic variables and oxygenation were assessed.
Results : Intubation time did not differ between suxamethonium (9.8±2.2 s) (mean±SD) and rocuronium (10.5±2.9 s), respectively. Intubating conditions were clinically acceptable (good or excellent) in all patients given suxamethonium and in 96% of the patients given rocuronium. However, the condition of the vocal cords was better (P<0.05) and diaphragmatic response to intubation was less pronounced with suxamethonium (P<0.05). Changes in heart rate and arterial blood pressure were similar in both groups.
Conclusion : The authors conclude that rocuronium is a suitable alternative to suxamethonium for rapid tracheal intubation even under unsupplemented thiopentone anaesthesia, at least in elective, otherwise healthy patients. Its use for rapid-sequence induction under emergency conditions, however, needs further investigation.     

The haemodynamic effects of rocuronium and vecuronium are different under balanced anaesthesia

Background: Rocuronium has been reported to have minimal haemodynamic effects. However, this conclusion has been drawn primarily from investigations conducted under narcotic-based anaesthesia. This study was designed to evaluate the cardiovascular effects of rocuronium under isoflurane/N20/fentanyl anaesthesia and to compare rocuronium's haemodynamic effects to those of vecuronium and pancuronium.
Methods: Anaesthesia was induced with fentanyl 2 μg/kg, thiopentone 4 mg/kg, and suxamethonium 0.5 mg/kg in 75 ASA I or II patients. After tracheal intubation, anaesthesia was maintained with isoflurane 0.5% and N₂0 50% in oxygen. Five min after intubation (baseline), patients randomly received either vecuronium 100 μg/kg, rocuronium 600 μg/kg, rocuronium 900 μg/kg, rocuronium 1200 μg/kg, or pancuronium 140 μg/kg. One min after administration of muscle relaxant, mean arterial pressure (MAP) and heart rate (HR) were recorded and were subsequently measured at 1-min intervals for the next 4 min.
Results: HR decreased significantly ( P <0.05) at all times compared to baseline in patients receiving vecuronium. HR significantly ( P < 0.05) increased in those receiving rocuronium 1200 μg/kg or pancuronium. Patients who received vecuronium had a sigruficant ( P < 0.05) decrease in MAP at all times compared to baseline. Comparing results between groups, patients who received rocuronium or pancuronium had significantly ( P < 0.05) higher MAP compared to those administered vecuronium.
Conclusion: The haemodynamic effects of rocuronium and vecuronium are different under balanced anaesthesia. Rocuronium may attenuate the fall in MAP that often occurs under balanced anaesthesia without surgical stimulation.     

Intubating conditions using cisatracurium after induction of anaesthesia with thiopentone

We studied tracheal intubation conditions produced by the muscle relaxant, cisatracurium, following induction of anaesthesia with fentanyl (2 μgkg⁻¹) and thiopentone (6 mgkg⁻¹). Sixty patients were randomly assigned to receive cisatracurium in a single bolus dose of either 0.15 or 0.20 mgkg⁻¹. Tracheal intubation was commenced 120 s after injection of the relaxant. The mean (SD) time taken to achieve intubation was significantly shorter in the 0.20 mgkg⁻¹ group (137 (16) s) than the 0.15 mgkg⁻¹ group (149 (12) s; p < 0.05). The intubating conditions were better after the larger dose. Our results suggest that when anaesthesia is induced using thiopentone, a dose of 0.20 mgkg⁻¹ of cisatracurium is recommended to ensure satisfactory intubating conditions.     

瑞芬太尼复合异丙酚麻醉诱导对气管插管条件及血流动力学的影响

目的对比不使用肌松剂的情况下,瑞芬太尼或芬太尼复合异丙酚麻醉诱导后对气管插管条件及血流动力学的影响。方法60名病人分为2组,诱导后2rain行气管插管术。分别记录诱导前、诱导后lmin及插管后2min的平均动脉压（MAP）和心率（Ha）。插管条件由操作者给予评分。结果两组插管成功率均为100％。瑞芬太尼组插管条件满意率80％,芬太尼73％。两组诱导后MAP和HR值较基础值均下降（P〈0．05）。插管后两组间的MAP值差异有统计学意义（P（0．05）。结论瑞芬太尼复合异丙酚麻醉诱导取得了同芬太尼复合异丙酚麻醉诱导一样良好的插管条件,在抑制插管引起的心血管反应方面瑞芬太尼组优于芬太尼组。     

Second dose thiopentone attenuates the haemodynamic response to laryngoscopy and intubation

The study was undertaken to evaluate the effectiveness of large (divided) thiopentone dosage on the peripheral haemodynamic response to laryngoscopy and intubation. Seventy-six (76) patient aged 18 to 67 years were sequentially assigned to either the second dose thiopentone group (n = 36) or the control group (n = 40). The first group had 4 mg.kg-1 thiopentone for induction of anaesthesia, then 1.5 mg.kg-1 suxamethonium chloride for muscle relaxation and a second dose of thiropentone (4 mg.kg-1) just before laryngoscopy and intubation. The control group had thiopentone 4 mg.kg-1 for induction of anaesthesia, suxamethonium 1.5 mg.kg-1 for muscle relaxation and then laryngoscopy and intubation. The heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), and rate pressure product (RPP) were measured before induction of anaesthesia and after laryngoscopy and intubation. The difference in the values represented the haemodynamic response to laryngoscopy and intubation. The second dose thiopentone technique compared with the control group, significantly attenuated the post-intubation rise in HR (19.7 vs. 30.9), SAP (18.0 vs. 37.5) and RPP (4795.4 vs. 8440.0). The post intubation rise in DAP (33.9 vs. 42.5) and MAP (31.9 vs. 42.0) didn't show significant difference between the two groups.     

Intramuscular dexmedetomidine premedication—an alternative to midazolam-fentanyl-combination in elective hysterectomy?

Sedation, anxiolysis, intubation responses and fentanyl anaesthetic requirements were investigated in a double-blind, randomized study in twenty ASA I-II elective hysterectomy patients. Ten patients received dexmedetomidine 2.5 μg kg^-1 i.m. 60 min before induction and saline placebo i.v. 2 min prior to induction (= DP group). Ten patients received midazolam 0.08 mg kg^-1 i.m. 60 min and fentanyl 1.5 μg kg^-1 i.v. (= MF group) 2 min before induction of anaesthesia with thiopentone 4 mg kg^-1. Anaesthesia was maintained with 70% nitrous oxide in oxygen and with fentanyl 2 μg kg^-1 i.v. increments according to predetermined criteria. Both premedications induced sedation ( P < 0.01 in both groups) and anxiolysis ( P < 0.01 in DP vs <0.05 in MF group) without any differences between the groups. Haemodynamic changes following tracheal intubation did not significantly differ between the groups. Intraoperatively systolic and diastolic arterial pressure were 15% and 13% lower in DP group ( P < 0.01 and P < 0.05 for drug effect), the mean heart rate was approximately 9 beats min^-1 lower in DP group (n.s.). Fentanyl was required more often in MF group: median 3.5 (QD 1.5) vs. 2.5 (QD 0.5) times in DP group ( P < 0.05), the total amount being 57% smaller in DP group: 0.03 (QD 0.01) vs. 0.07 (QD 0.02) μg kg^-1 min^-1 ( P < 0.05). Postoperative course and analgesic requirements were similar in both groups. Dexmedetomidine premedication may offer an alternative to current anaesthesia practice in elective hysterectomy.     

Assessment of tracheal intubating conditions in children using remifentanil and propofol without muscle relaxant

BACKGROUND: Tracheal intubation in children can be achieved by deep inhalational anaesthesia or an intravenous anaesthetic and a muscle relaxant, suxamethonium being widely used despite several side-effects. Studies have shown that oral intubation can be facilitated safely and effectively in children after induction of anaesthesia with propofol and alfentanil without a muscle relaxant. Remifentanil is a new, ultra-short acting, selective mu-receptor agonist that is 20-30 times more potent than alfentanil. This clinical study was designed to assess whether combination of propofol and remifentanil could be used without a muscle relaxant to facilitate tracheal intubation in children. METHODS: Forty children (5-10 years) admitted for adenotonsillectomy were randomly allocated to one of two groups to receive remifentanil 2 microg.kg(-1) (Gp I) or remifentanil 3 microg.kg(-1) (Gp II) before the induction of anaesthesia with i.v. propofol 3 mg.kg(-1). No neuromuscular blocking agent was administered. Intubating conditions were assessed using a four-point scoring system based on ease of laryngoscopy, jaw relaxation, position of vocal cords, degree of coughing and limb movement. Mean arterial pressure (MAP) and heart rate (HR) measured noninvasively before induction of anaesthesia to 5 min after intubation (seven time points). RESULTS: Tracheal intubation was successful in all patients without requiring neuromuscular blocking agent. Intubating conditions were clinically acceptable in 10 of 20 patients (50%) in Gp I compared with 18 of 20 patients (90%) in Gp II (P < 0.05). MAP and HR decreased in both groups after induction of anaesthesia (P < 0.01). Both HR and MAP were significantly lower in Gp II compared with Gp I after tracheal intubation (P < 0.01). No patient in the present study developed bradycardia or hypotension. CONCLUSIONS: We conclude that remifentanil (3 microg.kg(-1)), administered before propofol (3 mg.kg(-1)) provides acceptable tracheal intubating conditions in children, and completely inhibited the increase in HR and MAP associated with intubation.     

Influence of induction of anaesthesia on intubating conditions one minute after rocuronium administration: comparison of ketamine and thiopentone

We compared the effect of thiopentone and ketamine on intubating conditions after rocuronium 0.6 mg.kg-1 in two groups of patients (n = 16 each), aged 21-44 years, undergoing elective surgery. Premedication consisted of alprazolam 1 mg by mouth 1 h before surgery. All patients received midazolam 2 mg intravenously 2 min before intravenous administration of thiopentone 5 mg.kg-1 or ketamine 2.5 mg.kg-1. Muscle relaxation was provided by rocuronium 0.6 mg.kg-1. One minute after rocuronium administration, tracheal intubation was performed within 15 s by a skilled anaesthetist blinded to the treatment group assignment. Intubating conditions were graded as excellent, good, fair or poor on the basis of jaw relaxation, position of vocal cords and diaphragmatic response. Neuromuscular transmission was assessed at the adductor pollicis muscle using a TOF-GUARD monitor. Excellent and good intubating conditions were obtained in 100% of patients in the ketamine group and in 50% of patients in the thiopentone group (p = 0.002). Jaw relaxation was similar in both groups but vocal cord conditions were better and the diaphragmatic response less marked in the ketamine group compared with the thiopentone group (p = 0.002). The degree of neuromuscular block [% decrease of T1, mean (SD)] at the time of intubation was similar: 51.8 (25)% (ketamine group) and 54.3 (23.1)% (thiopentone group). We conclude that ketamine 2.5 mg.kg-1 provides better intubating conditions than thiopentone 5 mg.kg-1 1 min after administration of rocuronium 0.6 mg.kg-1.     

Partial attenuation of the cardiovascular responses to tracheal intubation with oral manidipine

We conducted a placebo–controlled, randomized, and double–blinded study to evaluate the efficacy of manidipine given orally in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation. Thirty normotensive patients (ASA physical status 1) undergoing elective surgery were allocated to one of three groups (n= 10 for each); placebo, 5 mg manidipine, and 10 mg manidipine groups. These tablets were orally administered 3 h before induction of anaesthesia. Anaesthesia was induced with thiopentone 5 mg kg^-1 iv , and tracheal intubation was facilitated with vecuronium 0.2 mg–kg^-1. Laryngoscopy lasting 30 sec was attempted 2 min after induction of anaesthesia. Patients receiving placebo showed a significant increase in systolic and diastolic blood pressure associated with tracheal intubation. These increases following tracheal intubation were significantly reduced in patients receiving manidipine 10 mg compared with patients receiving placebo or manidipine 5 mg ( P < 0.05). Oral administration of manidipine 10 mg before induction of anaesthesia is a simple and effective method for attenuating pressor response to laryngoscopy and tracheal intubation. We stressed that the potential beneficial effect of a reduced haemodynamic reaction to intubation might be obtained at the expense of hypotension later on.     

Propofol influences the electroretinogram to a lesser degree than thiopentone

Background: The Electroretinogram (ERG) is used clinically to assess the function of retina. Anaesthetic agents are known to affect ERG, and as anaesthesia is often needed in children and uncooperative patients, knowledge about its effects is of clinical importance. Barbiturates selectively depress ERG components, and we compared thiopentone with propofol to assess if the latter preserved retinal function better.
Methods: Ten pigs, average weight 17 kg (SD ± 2 kg) were anaesthetized randomly with propofol 10 mg kg^-1 or thiopentone 30 mg kg^-1. Anaesthesia was maintained by 65% nitrous oxide in oxygen and continuous infusion of the induction agent, i.e. 10 mg kg^-1 h^-1 of propofol, or 10 mg kg^-1 h^-1 for the first hour, then 5 mg kg^-1 h^-1 of thiopentone, with doses being based on pilot studies. After an interval of one week the programme was repeated using the other agent. After 40 minutes dark-adaptation, responses to single flashes of graded intensities from a xenon flashlamp were recorded at five-minute intervals. The a- and b-wave amplitudes and implicit times (time to peak), and a-wave slopes were determined.
Results: The b-wave implicit time was significantly shorter during propofol anaesthesia than when using thiopentone. The effect was most pronounced at the lowest intensities (P < 0.01). No statistically significant differences were found in the amplitudes of the b-waves. The a-wave appeared at lower stimulus intensity (P < 0.05) and the a-wave slopes were significantly steeper (P < 0.01) during propofol anaesthesia.
Conclusion: Propofol accordingly appeared to preserve the photoreceptor response better than thiopentone, and may therefore be considered to be more suitable for ERG recordings than thiopentone.     

Comparison of nicardipine, diltiazem and verapamil for controlling the cardiovascular responses to tracheal intubation

We have compared the efficacy of three calcium channel blockers, nicardipine, diltiazem and verapamil, in attenuating the cardiovascular responses to laryngoscopy and intubation in 60 normotensive patients (ASA I) undergoing rapid sequence induction of anaesthesia with thiopentone and fentanyl. We also examined whether or not these blockers inhibited catecholamine release induced by intubation. The patients were allocated to one of four groups (n = 15 for each): saline (control), nicardipine 30 micrograms kg-1, diltiazem 0.2 mg kg-1 or verapamil 0.1 mg kg-1. Verapamil and the three other drugs were administered 45 s and 60 s before the start of direct laryngoscopy, respectively, in a double-dummy design. Anaesthesia was induced with thiopentone 4 mg kg-1 i.v. and fentanyl 2 micrograms kg-1 i.v. Tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% isoflurane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30 s was attempted 2 min after administration of thiopentone and vecuronium. Patients receiving saline exhibited significant increases in systolic and diastolic arterial pressures (AP), heart rate (HR) and plasma concentrations of catecholamines associated with tracheal intubation. The increase in AP was attenuated in patients treated with any calcium channel blocker. The greatest effect was elicited by verapamil, which attenuated the increase in HR, although nicardipine seemed to enhance tachycardia. All three drugs failed to suppress the increase in plasma catecholamine concentrations in response to tracheal intubation. These findings suggest that bolus injection of verapamil 0.1 mg kg-1 was a more effective method of controlling hypertension and tachycardia associated with intubation than diltiazem 0.2 mg kg-1 or nicardipine 30 micrograms kg-1, and that these prophylactic effects were not caused by inhibition of the catecholamine response.      

RETRACTED ARTICLE: Circulatory responses to laryngeal mask airway insertion or tracheal intubation in normotensive and hypertensive patients

The effects of laryngeal mask airway (LMA) insertion and tracheal intubation on circulatory responses were studied in normotensive (n = 24) and hypertensive (n = 22) patients. In a randomized, double-blind manner, LMA insertion or tracheal intubation was performed after induction of anaesthesia with thiopentone and muscle relaxation with succinylcholine. In both normotensive and hypertensive patients, heart rate (HR), mean arterial pressure (MAP) and rate-pressure product increased after tracheal intubation or LMA insertion compared with base-line (P < 0.05). The haemodynamic changes were greater after intubation than after LMA insertion (P < 0.05). Following intubation of the trachea or insertion of the LMA, HR increased more markedly in hypertensive patients than in normotensive patients (P < 0.05). Plasma adrenaline and noradrenaline concentrations after tracheal intubation or LMA insertion increased compared with baseline values (P < 0.05) in normotensive and hypertensive patients. The increase in noradrenaline concentration after tracheal intubation was greater than that after LMA insertion (P < 0.05). No patient revealed ECG evidence of myocardial ischaemia. We conclude that insertion of LMA is associated with less circulatory responses than tracheal intubation in both normotensive and hypertensive patients.     

The influence of the duration of isoflurane anaesthesia on neuromuscular effects of mivacurium

Background: The pharmacodynamic profile of muscle relax-ants is usually changed by volatile anaesthetics. These changes seem to be time-dependent, even though few data are available to substantiate this.
Methods: We studied neuromuscular effects of a single dose of mivacurium (0.2 mg·kg^-1) during short and intermediate duration of isoflurane anaesthesia. Forty-five children 1–10 years of age were randomized to receive 1.5% end-tidal concentration of isoflurane in N₂O/O₂ for 10 or 30 min (groups Iso-10 and Iso-30, respectively) or to receive nitrous oxide in oxygen for 10 min (Group N₂O) before 0.2 mg · kg^-1 of mivacurium was given. Neuromuscular response was recorded by adductor pollicis electromyogram.
Results: The onset time of mivacurium was shorter in Group Iso-30, 1.7 (1.0–2.3) min than in Group Iso-10, 2.3 (1.7-3.3) rnin or Group N₂O, 2.3 (1.7-3.3) min (median with 10–90% percen-tiles) ( P <0.05). In Group Iso-30 the recovery time of the first EMG response was significantly longer than in groups Iso-10 and N₂O ( P <0.0001). Groups Iso-10 and N₂O did not differ from each other.
Conclusions: Our results indicate that the duration of a constant concentration of isoflurane anaesthesia influences significantly the pharmacodynamics of mivacurium. The duration of a volatile anaesthesia is critical when potentiation of NMB is evaluated or compared in neuromuscular studies.     

Comparison of subhypnotic doses of thiopentone vs propofol on the incidence of postoperative nausea and vomiting following middle ear surgery

Background : Middle ear surgery is associated with a high incidence of emetic sequelae and propofol has been reported to have antiemetic activity in subhypnotic doses.
Methods : In a double-blind, randomized study, the patients received either thiopentone 1.0 mg.kg^-1 (n=26) or 0.5 mg.kg^-1 propofol (n=26) at the end of middle ear surgery under isoflurane-N₂O-fentanyl-vecuronium anaesthesia. Trained nurses, unaware of the group assignment, assessed postoperative nausea, retching and vomiting up to 24 h after the end of anaesthesia. Droperidol 10μg.kg^-1 was used as a "rescue" antiemetic.
Results : The main result was that the patients in the propofol group did not suffer from retching and vomiting (R&V) during the first 6 h, whereas these symptoms occurred in 46% ( P <0.001) of the patients in the thiopentone group. The patients in the propofol group needed significantly less droperidol during the first 24 h (mean number of doses 0.39 ± 0.57 (SD)) than the patients in the thiopentone group (1.35 ± 1.47, P <0.005). Treatment with propofol was a predictor for lowered incidence of R&V, as well as male gender and negative history of motion sickness.
Conclusion : Propofol at a subhypnotic dose of 0.5 mg.kg^-1 provides prophylaxis against retching and vomiting for the first 6 h postoperatively after middle ear surgery. The incidence of nausea was not reduced by propofol.     

Sevoflurane requirements for tracheal intubation with and without fentanyl

We studied 80 healthy ASA 1 patients (aged 20-52 yr) to determine if fentanyl affects sevoflurane requirements for achieving 50% probability of no movement in response to laryngoscopy and tracheal intubation (MAC- TI). Patients were allocated randomly to one of four fentanyl dose groups (0, 1, 2 and 4 micrograms kg-1). Patients in each group received sevoflurane at a pre-selected end-tidal concentration according to an 'up-down' technique. After steady state sevoflurane concentration had been maintained for at least 10 min, fentanyl was administered i.v. Tracheal intubation was performed 4 min after administration of fentanyl, and patients were assessed as moving or not moving. Heart rate (HR) and mean arterial pressure (MAP) were recorded before induction of anaesthesia, just before administration of fentanyl, just before laryngoscopy for intubation, and after intubation. The MAC-TI of sevoflurane was 3.55% (95% confidence intervals 3.32-3.78%), and this was reduced markedly to 2.07%, 1.45% and 1.37% by addition of fentanyl 1, 2 and 4 micrograms kg-1, with no significant difference in the reduction between 2 and 4 micrograms kg-1, showing a ceiling effect. Fentanyl attenuated haemodynamic responses (HR and MAP) to tracheal intubation in a dose-dependent manner, even with decreasing concomitant sevoflurane concentration. Fentanyl 4 micrograms kg-1 suppressed the changes in HR and MAP more effectively than fentanyl 1 or 2 micrograms kg-1 at sevoflurane concentrations close to MAC-TI.      

Comparative evaluation of different doses of propofol preceded by fentanyl on intubating conditions and pressor response during tracheal intubation without muscle relaxants

BACKGROUND: The aim of our study was to determine the optimal dose of propofol preceded by fentanyl for successful tracheal intubation and to see its effectiveness in blunting pressor response in children aged 3-10 years. METHODS: This prospective, double blind, randomized study was conducted on 60 ASA grade I and II children, between 3 and 10 years undergoing elective surgery who were divided into three groups of 20 each. The children received different doses of propofol (group I, 2.5 mg x kg(-1); group II, 3.0 mg x kg(-1); group III, 3.5 mg x kg(-1)) preceded by a fixed dose of fentanyl (3.0 microg x kg(-1)) 3 min earlier. The tracheal intubating conditions were graded based on scoring system devised by Helbo-Hensen et al. with Steyn modification which includes five criteria; ease of laryngoscopy, degree of coughing, position of vocal cords, jaw relaxation, and limb movement and graded on a 4-point scale. Heart rate (HR), mean arterial pressure (MAP), and oxygen saturation changes were also noted. RESULTS: Tracheal intubating conditions were acceptable in 25% of the patients in group I, while significantly higher (P < 0.001) in group II (80%) and in group III (90%). The pressor response was not effectively blunted in group I (17% increase in HR), while effectively blunted in groups II and III. A fall in cardiac output was seen in group III indicated by a decrease in MAP (16%) and HR (11%). No airway complications were noted. CONCLUSIONS: Propofol 3 mg x kg(-1) (group II) preceded by fentanyl 3 microg x kg(-1) is the optimal dose combination in our study. It provides acceptable intubating conditions in 80% patients, blunts pressor response to intubation without significant cardiovascular depression.     

Blood flow and mivacurium-induced neuromuscular block at the orbicularis oculi and adductor pollicis muscles

We have studied the pattern of blood flow and pharmacodynamic profile of mivacurium-induced block at the adductor pollicis and orbicularis oculi muscles. We studied 30 adult patients anaesthetized with fentanyl, thiopentone, nitrous oxide-isoflurane, and mivacurium 0.2 mg kg-1. Neuromuscular transmission was monitored with accelerometry (TOF Guard, Biometer, Denmark). Blood flow was measured at the two muscles with the use of a laser Doppler flowmeter (Laserflo BPM2, Vasamedics, USA). All patients developed 100% neuromuscular block at the adductor pollicis muscle. Mean maximum neuromuscular block at the orbicularis oculi was 96.4 (SD 3.5)% (ns). Onset time, time required for 25% and 75% recovery of the first twitch in the train-of-four (T1), and a train- of-four ratio (T4/T1) of 90% at the orbicularis oculi were respectively, mean 130.4 (SD 28.5) s, 9.1 (3.2) min, 16.2 (3.9) min and 20.2 (4.3) min and were significantly shorter than the corresponding values at the adductor pollicis: 202.7 (37.2) s, 12.9 (3.9) min, 21.1 (5.1) min and 30.8 (7.4) min. For a given T1, there was significantly less train-of-four fade (T4/T1) at the orbicularis oculi than at the adductor pollicis muscle during recovery. Blood flow was comparable at the two muscles before induction of anaesthesia. Thiopentone significantly increased thenar muscle blood flow from 2.9 (1.5) to 12.3 (6.8) ml 100 g-1 min-1, with a further increase to 22.7 (8.0) ml 100 g- 1 min-1 after isoflurane (P < 0.001). Blood flow at the orbicularis oculi was not altered by thiopentone or isoflurane and was consistently lower than that at the adductor pollicis muscle. We conclude that the different pharmacodynamic profiles of mivacurium-induced block at the orbicularis oculi and adductor pollicis muscles were not related primarily to a difference in blood flows.      

Comparison of propofol/alfentanil anaesthesia with isoflurane/N2O/fentanyl anaesthesia for renal transplantation

Total intavenous anaesthesia (TIVA) with propofol and alfentanil was compared with balanced anaesthesia (BA) in 30 uraemic patients undergoing renal transplantation. TIVA (n=15) was induced with propofol and alfentanil and maintained with propofol and alfentanil infusions, which were started immediately after induction. Thereafter the infusion rates were adjusted as needed. Ventilation was with oxygen in air. BA (n= 15) was induced with thiopentone and fentanyl and maintained with isoflurane/N20/fentanyl. Vecuronium was used for muscle relaxation in both groups. Mean infusion rates for propofol and alfentanil were 10 1.8 mg kg^-1 h^-1 and 70 9 μg kg^-1 h^-1, respectively. To control hypertension during TIVA, larger amounts of propofol and alfentanil were needed and slower recovery was observed than in previous studies in ASA 1–2 patients. Also, significantly more vecuronium was needed during TIVA than during BA ( P < 0.05). The recovery parameters were similar in both groups, except for the occurrence of nausea, which was less after TIVA. In conclusion, TIVA had no clinical advantages over BA.     

The effect of cortisol suppression on interleukin-6 and white blood cell responses to surgery

Background: The endocrine and immune changes associated with surgery are well documented, but the interaction between them has not been fully evaluated. Cortisol production during surgery can be suppressed by etomidate and we have used this to investigate the relationshp between the cortisol response and immune changes in the perioperative period.
Methods: We have measured the cortisol, interleukin-6 and white cell responses to elective abdominal hysterectomy in 8 healthy female patients, who received etomidate 0.3 mg kg^-1 for induction of anaesthesia. A control group of 8 subjects received thiopentone. Both groups of patients received vecuro-nium and fentanyl 2 yg kg^-1 and anaesthesia was maintained with nitrous oxide in oxygen and isoflurane 0.5-1.0%. Venous blood samples were collected before and during surgery and up to 24 h in the postoperative period.
Results: Serum interleukin-6 values were significantly greater at 6 and 12 h ( P <0.05) in those patients who received etomidate. Inhibition of the serum cortisol response to surgery in the etomidate group was also associated with less marked lymphopenia at 4 h ( P <0.05). There was no significant difference in neutrophil granulocyte counts between the two groups.
Conclusions: In conclusion, endogenous corticosteroids modulate the interleukin-6 response to surgery.     

Neuromuscular blockade monitoring at the corrugator supercilii and ocular myasthenia gravis

A 67-year-old patient suffering from an ocular myasthenia gravis was scheduled for an elective ENT surgery. General anaesthesia was induced intravenously. Neuromuscular responses after train-of-four stimulation were normal at both the adductor pollicis (T(4)/T(1) = 1) and the corrugator supercilii (4 visual responses). Then cisatracurium (0,15 mg kg(-1)) was administered to allow tracheal intubation. The laryngoscopy attempted 45 s after cisatracurium injection (no response at the supercilii, T(1)/T(0) = 1 at the adductor pollicis) was unsuccessful because of closing and moving vocal cords. The second attempt was successful 4 min after cisatracurium injection (no response at the corrugator supercilii, T(1)/T(0) = 0.05 at the adductor pollicis). Residual neuromuscular blockade was antagonized at the end of surgery (1 h long) allowing an uneventful extubation. We concluded that monitoring neuromuscular blockade at the corrugator supercilii to assess the intubating conditions is not recommended in a case of ocular myasthenia gravis.