Summary

Background and objective: The electroencephalographic Narcotrend Index (NI) is a measure of the hypnotic component of general anaesthesia. The purpose of this study was to evaluate the impact of Narcotrend guidance on propofol consumption and emergence times in children receiving total intravenous anaesthesia with propofol and remifentanil. Methods: Thirty children, aged 1–11 yr, scheduled for paediatric urological surgery were enrolled. Remifentanil was given to all patients at a constant infusion rate of 0.3 μg kg−1 min−1 throughout anaesthesia. Patients were randomly allocated to receive a continuous propofol infusion adjusted either according to a conventional clinical practice (Group C: n = 15) or guided by Narcotrend monitoring (Group NI: n = 15; target NI 60 ± 5). All patients were connected to the Narcotrend Monitor, but in Group C the anaesthetist was blinded to the screen of the monitor. Propofol consumption (mg kg−1 h−1) and emergence times (min) were the primary and secondary outcome measures. Results: Propofol consumption (median [inter-quartile range]) was significantly lower in Group NI compared to Group C (NI: 7.0 [6.4–8.2] vs. C: 9.3 [8.3–11.0] mg kg−1 h−1; P < 0.001), whereas Log-Rank-analysis revealed no intergroup difference in emergence times (Group NI: mean [95% confidence interval (CI)] 12.8 [11.2–14.4] min; Group C: 16.4 [12.6–20.2] min; P = 0.10). Haemodynamic variables remained stable within age-related limits, and there were no observations of adverse events, especially no clinical signs of intraoperative awareness in any patient. Conclusion: Narcotrend monitoring for guidance of propofol/remifentanil anaesthesia in children results in reduced propofol consumption compared to a conventional clinical practice.

Summary

Background and objective: Accurate assessment of preload responsiveness is an important goal of the clinician to avoid deleterious volume replacement associated with increased morbidity and mortality in mechanically ventilated patients. This study was designed to evaluate the accuracy of simultaneously assessed stroke volume variation and pulse pressure variation using an improved algorithm for pulse contour analysis (PiCCO plus®, V 5.2.2), compared to the respiratory changes in transoesophageal echo-derived aortic blood velocity (ΔVpeak), intrathoracic blood volume index, central venous pressure and pulmonary capillary wedge pressure to predict the response of stroke volume index to volume replacement in normoventilated cardiac surgical patients. Methods: We studied 20 patients undergoing elective coronary artery bypass grafting. After induction of anaesthesia, haemodynamic measurements were performed before and after volume replacement by infusion of 6% hydroxyethyl starch 200/0.5 (7 mL kg−1) with a rate of 1 mL kg−1 min−1. Results: Baseline stroke volume variation correlated significantly with changes in stroke volume index (ΔSVI) (r2 = 0.66; P < 0.05) as did baseline pulse pressure variation (r2 = 0.65; P < 0.05), whereas baseline values of ΔVpeak, intrathoracic blood volume index, central venous pressure and pulmonary artery wedge pressure showed no correlation to ΔSVI. Pulse contour analysis underestimated the volume-induced increase in cardiac index measured by transpulmonary thermodilution (P < 0.05). Conclusions: The results of our study suggest that stroke volume variation and its surrogate pulse pressure variation derived from pulse contour analysis using an improved algorithm can serve as indicators of fluid responsiveness in normoventilated cardiac surgical patients. Whenever changes in systemic vascular resistance are expected, the PiCCO plus® system should be recalibrated.

Summary

Recently published literature shows that most patients experience a variety of visual sensations during cataract surgery under local anaesthesia. Most patients (80–100%) retain at least some light perception in the operated eye and many also experience a variety of other visual sensations during cataract surgery under regional ophthalmic anaesthesia (retrobulbar, peribulbar and sub-Tenon's blocks) or topical anaesthesia. The visual sensations experienced include perception of movements, flashes, colours, changes in brightness, or the sight of surgical instruments, the surgeon's hands or fingers, or even the surgeon. These findings are clinically significant because 3–16.2% of patients who had cataract surgery under either regional or topical anaesthesia were frightened by their intraoperative visual experience. Fear and anxiety may cause some patients to become uncooperative during the surgery and may also induce a sympathetic stress response that might cause hypertension, tachycardia with myocardial ischaemia, hyperventilation or an acute panic attack. These effects are especially undesirable as the majority of cataract patients are elderly and have concurrent medical problems. Besides increasing the risk of intraoperative complications, a frightening visual experience may decrease patient satisfaction. Appropriate preoperative counselling has been shown to be effective in reducing the patients' fear. As most patients retain some visual function during cataract surgery under local anaesthesia, anaesthesia providers should be mindful of this phenomenon and offer appropriate preoperative information and counselling to their patients.

Summary

Background and objective: The purpose of this prospective randomized study was to assess the value of pressure support ventilation during inhalational induction with sevoflurane in adult patients. Methods: Thirty-five adult patients, ASA I–II and scheduled for ear nose throat surgery were studied. Vital capacity induction with 8% sevoflurane in 8 L min−1 oxygen was performed. Pressure support ventilation was used in Group 1 with pressure set at 15 cmH2O. In Group 2, patients breathed spontaneously. After 2 min, sevoflurane was set to 3% and remifentanil 1 μg kg−1 was injected over 2 min followed by an infusion of 0.1μg kg−1 min−1. Two minutes after the end of the bolus, intubation was performed. Bispectral index, oxygen saturation, respiratory rate, end-tidal carbon dioxide, expired tidal volume and expired sevoflurane concentration were recorded every minute. Results: Eighteen patients were included in Group 1 and 17 in Group 2. Saturation, respiratory rate and end-tidal carbon dioxide were similar in the two groups. Expired tidal volume was significantly higher and bispectral index values significantly lower in Group 1. Intubating conditions were better in Group 1. Conclusions: Pressure support ventilation provides both better ventilation and deeper level of anaesthesia during inhalation induction with sevoflurane.

Summary

Background and objective: This study clarifies the relationship between the neuromuscular blocking effects of rocuronium 0.6 mg kg−1 and its pharmacokinetics in patients with renal failure.

Methods: Seventeen healthy patients and 17 patients with renal failure were studied under propofol anaesthesia in this prospective open label study. Rocuronium 0.6 mg kg−1 was given after induction of anaesthesia. The train-of-four mechano-myographic response of the thumb to supramaximal stimulation of the ulnar nerve at 2 Hz every 12 s was measured. Venous blood samples (4 mL) were obtained at 0, 2, 4, 7, 10, 15, 20, 30, 60, 120, 180, 240 and 360 min after relaxant administration. Samples were centrifuged, separated and stored at −20°C until plasma levels of rocuronium and its metabolites were measured. Two- and three-exponential equations were used to describe the pharmacokinetic data in each group and these were compared to each other using the Wilcoxon signed rank sum test as was the pharmacodynamic data. P < 0.05 was significant.

Results: Onset of block was similar in both groups. Clinical duration and the time to recovery of the train-of-four to 70% were prolonged in the renal failure group compared to control; 49 vs. 32 min (P < 0.004, 95% confidential interval 17, difference 5–28) and 88 vs. 55 min (P < 0.001, 95% confidential interval 33, difference 17–50), respectively. Clearance of rocuronium was reduced by 39% in the renal failure patients compared to control, with an 84% increase in the mean residence time. The volume of distribution was unaffected by renal failure.

Conclusions: The duration of action of a bolus dose of 0.6 mg kg−1 rocuronium is increased significantly in patients with end-stage renal failure compared to healthy controls. This increase may be due to a decreased clearance of rocuronium, the disease process causing the renal failure and/or the medication which patients with renal failure need in their treatment.

Summary

Background and objective: An evaluation of post-craniotomy analgesia within the University Hospital of Wales Neurosurgical Unit, Cardiff, found that many patients were experiencing moderate to severe pain post-craniotomy. It was therefore decided to undertake a nationwide survey of analgesic practices in order to establish best practice guidelines and benchmark with other units.

Method: A postal questionnaire was sent to the senior nurse of every Neurosurgical Directorate within the UK inquiring about the current, standard analgesic practices for post-craniotomy patients in their unit.

Results: Completed replies were received from 23 of the 33 centres (70%). Intramuscular (i.m.) codeine phosphate was found to be the principal first-line analgesic used post-craniotomy. Only three centres used morphine as the first-line analgesic and only one centre used patient controlled analgesia routinely. The majority of centres (82%) used balanced analgesia. Pain assessments were only carried out in 57% of centres and no centre used a validated pain assessment tool specifically for dysphasic patients.

Conclusions: Codeine phosphate continues to be the mainstay of post-craniotomy analgesia, however, it is proposed that patient controlled analgesia with morphine is an efficacious and safe alternative.

Summary

Background and objective: A study was designed to utilise the resources of our computerised anaesthesia record keeping system to assess the attributable effects of increased preoperative creatinine (>1.3 mg dL−1) on outcome in patients undergoing non-cardiac surgery.

Methods: This retrospective study was based on data sets of 58 458 patients recorded with a computerised anaesthesia record keeping system over a period of 4 yr at a tertiary care university hospital. Cases were defined as patients with a preoperative creatinine >1.3 mg dL−1; controls (creatinine ≤1.3 mg dL−1) were selected and automatically matched according to several parameters (ASA physical status, high risk and urgency of surgery, age and gender) in a stepwise fashion. Main outcome measures were hospital mortality and the incidence of intraoperative cardiovascular events.

Results: Three-thousand-and-twenty-eight patients (5.2%) had preoperative creatinine values >1.3 mg dL−1. Matching was successful for 54.5% of the cases, leading to 1649 cases (mean creatinine 3.3 ± 2.2 mg dL−1) and 1649 controls (1.0 ± 0.2 mg dL−1). The crude mortality rates for the cases and matched controls were 2.2% (n = 36) and 0.9% (n = 15), respectively (P = 0.003). Intraoperative cardiovascular events were found in 30.1% of the patients (n = 496) and in 28.3% of the matched controls (n = 466; P = 0.25, power = 0.46). Using logistic regression analyses a significant association between preoperative increased creatinine and hospital mortality was found (odds ratio 2.62; 95% confidence interval [1.39; 4.93]).

Conclusions: An increased preoperative serum creatinine in patients undergoing non-cardiac surgery is associated with an increased perioperative risk, but not with a higher incidence of intraoperative cardiovascular events.

Summary

Background and objective: The aim was to determine whether the administration of aprotinin can cause deleterious effects on renal function in cardiac surgery with cardiopulmonary bypass (CPB). Methods: Sixty consecutive patients with normal preoperative renal function undergoing elective coronary artery bypass surgery with CPB using the same anaesthetic; CPB and surgical protocols were randomized into three groups. Patients received placebo (Group 1), low-dose aprotinin (Group 2) or high-dose aprotinin (Group 3). Renal parameters measured were plasma creatinine, α1-microglobulin and β-glucosaminidase (β-NAG) excretion. Measurements were performed before surgery, during CPB and 24 and 72 h, and 7 and 40 days postoperatively. Results: In the three groups, α1-microglobulin and β-NAG excretions significantly increased during CPB, at 24 and 72 h, and 7 days postoperatively (P < 0.05) and had returned to preoperative levels at postoperative day 40. Plasma creatinine levels were within normal values at times recorded. In Groups 2 and 3, α1-microglobulin excretion during CPB was significantly higher than in Group 1 (P < 0.001), and 24 h after surgery it still remained significantly higher in Group 3 compared to Groups 1 and 2 (P < 0.05). Conclusions: Aprotinin caused a significant increase in α1-microglobulin excretion but not in β-NAG excretion during CPB, which may be interpreted as a greater renal tubular overload without tubular damage. This effect persisted for 24 h after surgery when high-dose aprotinin doses had been administered. Creatinine plasma levels were not sensitive to detect these prolonged renal effects in our study.

Summary

Background and objective: To compare the onset of action, and quality of block, of lidocaine 2% with levobupivacaine 0.75% for sub-Tenon's block in patients undergoing cataract surgery. Methods: We performed a two-centre trial in 91 patients who were randomized to receive 4 mL of lidocaine 2% (n = 44) or levobupivacaine 0.75% (n = 47) for sub-Tenon's block, both with hyaluronidase 15 IU mL−1. Onset of akinesia was assessed every 2 min for 10 min. Numbers of patients requiring supplementary injections to achieve clinically satisfactory akinesia or rescue analgesia were recorded. Data were analyzed with Fisher's exact test, U-test and t-test where appropriate. Results were considered significant when P < 0.05. Results: The speed of onset was statistically significantly faster for lidocaine compared to levobupivacaine (3.02 vs. 5.06 min, P < 0.001). There was no statistical difference in number of patients requiring a supplementary injection of local anaesthetic (levobupivacaine 3 vs. lidocaine 0, P = 0.24), rescue analgesia with topical tetracaine (levobupivacaine 0 vs. lidocaine 2, P = 0.5), or ocular akinesia scores at the completion of surgery (lidocaine 1.4 vs. levobupivacaine 1.6, P = 0.12). Pain scores measured by a verbal analogue scale were not significantly different for injection, perioperatively or postoperatively. Conclusions: Both agents produce a rapid onset of anaesthesia when used for sub-Tenon's block. The difference between the two agents, although statistically significant, is not clinically important.

Summary

Background: We have evaluated the use of the TOF-Guard® (TOF, train-of-four) acceleromyographic thumb responses to ulnar nerve stimulation in neonates and infants and the return of the responses after neuromuscular blockade.

Methods: Baseline acceleromyographic recording of thumb adduction to ulnar nerve stimulation during volatile anaesthesia was performed in 22 babies aged less than 30 weeks. At the start of stimulation the automatic set-up procedure of the TOF-Guard® was used to see if a 100% control twitch height could be achieved. Irrespective of the ability to achieve a 100% control twitch height, TOF stimulation was used thereafter. When no automatic 100% control twitch could be reached, the transducer signal gain factor was set manually to obtain a 100% value. In 14 of the 22 children the recovery after neuromuscular blockade with rocuronium 0.3 mg kg−1 was recorded.

Results: In nine of 22 patients a 100% baseline twitch height was obtained with the automatic set-up. In the other 13 babies the TOF-Guard® display indicated that the transducer signal was too low. The mean time to recovery of control twitch to 75% of baseline after rocuronium 0.3 mg kg−1 was 51 min (SD = 21) and the time to recovery of the TOF ratio to 70% was 49 min (SD = 19). The mean final twitch height and TOF after recovery from rocuronium blockade were 101% (SD = 15) and 92% (SD = 12), respectively.

Conclusion: The recovery of the responses after neuromuscular blockade to near baseline values shows that acceleromyography can be used to measure neuromuscular block and recovery in neonates and infants.

Summary

Background and objective: Increased inspired oxygen fractions (FiO2) have significant haemodynamic effects in awake volunteers. We sought to establish whether these effects are also present in anaesthetized patients.

Methods: We prospectively studied 30 ASA I–II patients, 15 in each of a propofol and sevoflurane group. Their haemodynamic responses, awake and anaesthetized, when the FiO2 was changed between 0.3 and 1.0 were measured with a non-invasive transthoracic bio-impedance monitor.

Results: While preoxygenating awake patients in both groups the FiO2 was increased from 0.21 to 1.0. This reduced the mean cardiac index (3.38 ± 0.5 to 3.03 ± 0.5 L min−1 m−2; P < 0.001); reduced the heart rate (HR) (68.1 ± 10.4 to 62.8 ± 9.4 beats per minute (bpm); P < 0.001); and reduced the stroke index (50.4 ± 9.6 to 48.5 ± 8.6; P = 0.02). It increased the systemic vascular resistance index (2060 ± 319 to 2220 ± 382 dyn s−1 cm−5 m−2; P = 0.002); but did not change mean arterial pressure. In the anaesthetized patients, when decreasing the FiO2 from 1.0 to 0.3, mean cardiac index (L min−1 m−2) increased (3.06 ± 0.57 to 3.25 ± 0.56, P = 0.008 for sevoflurane; 2.76 ± 0.46 to 2.89 ± 0.42, P = 0.002 for propofol). The mean HR (bpm) increased (65.1 ± 7.8 to 69.1 ± 7.5, P < 0.001 for sevoflurane; 67.5 ± 11.8 to 72.7 ± 11.6, P = 0.001 for propofol). The mean systemic vascular resistance (dyn s−1 cm−5 m−2) decreased (1883 ± 329 to 1735 ± 388, P = 0.008 for sevoflurane; 2015 ± 369 to 1771 ± 259, P = 0.003 for propofol). Mean arterial pressure (mmHg) decreased (74.8 ± 8.7 to 71.4 ± 8.7, P < 0.001 for sevoflurane; 72.1 ± 8 to 66.5 ± 6.8, P = 0.002 for propofol).

Conclusion: O2 has haemodynamic effects in awake and anaesthetized patients. These effects were of overall similar magnitude for patients anaesthetized with propofol and sevoflurane.

Summary

Background and objective: Although the pressure–volume (P–V) curve has been proposed in the management of mechanically ventilated patients, its interpretation remains unclear. Our aim has been to study the variations of the P–V curve after a recruitment manoeuvre (RM). Our hypothesis was that the lower inflection point (LIP) represents the presence of compressive atelectases, so it should not change after lung recruitment, while the upper inflection point (UIP) reflects reabsorptive atelectases, and an effective recruitment should result in changes at this level.

Methods: Two P–V curves (quasi-static method) separated by an RM (40 cmH2O, two consecutive manoeuvres) were plotted in 35 postoperative patients with criteria of acute lung injury/acute respiratory distress syndrome (ARDS). LIP, UIP and expiratory inflection point (EIP) were defined as the first point where the curve consistently starts to separate from the line.

Results: One to six measurements were obtained per patient (73 procedures). Neither the lower nor the EIPs varied significantly after the RM (P = 0.11 and 0.35, respectively). An UIP was observed in 18 curves (25%) before the RM and disappeared on nine occasions after the recruitment. Similar results were obtained when first measurements only were analysed, and when the cause (pulmonary vs. extrapulmonary), severity of lung injury or duration of mechanical ventilation at first measurement were studied.

Conclusions: An RM does not modify the LIP significantly, but induces the disappearance of the UIP in 50% of the cases in which this point is found.

Summary

Background and objective: The exact change in circulating blood volume (BV) during general anaesthesia is still unknown because there is no standard method of evaluating BV. We evaluated the changes in BV by general anaesthesia using simple and easy estimation methods.

Methods: Fourteen patients scheduled for minor surgery under general anaesthesia were enrolled. Propofol and vecuronium bromide were used for the induction of anaesthesia, and anaesthesia was maintained with sevoflurane and nitrous oxide. Haematocrit (Hct), total protein concentration (TP), as well as colloid osmotic pressure (COP) measured using a colloid osmometer, were determined before anaesthesia, and 30, 60 and 90 min after the induction of general anaesthesia. BV was calculated using Allen's formula and the changes in Hct, TP and COP. The estimated BV was compared with directly measured BV using indocyanine green dilution method (BVICG).

Results: Hct, TP and COP significantly decreased after the induction of anaesthesia (Hct: 42.1–39.4%; TP: 7.3–6.9 g dL−1; COP: 23–19 mmHg). The calculated BV as well as BVICG significantly increased after induction of anaesthesia (calculated by COP: 4.13–5.03 L; BVICG: 4.54–5.56 L). The change rate in BV calculated by the change of COP was larger than other calculated BVs, and was approximated to the change rate in BVICG. After emergence from anaesthesia, all values tended to return to baseline.

Conclusions: General anaesthesia increases BV. The value of BV calculated from the change in COP was most changeable.

Summary

Background and objective: High doses of opioid associated with low doses of hypnotic is a popular anaesthetic technique since the use of remifentanil has become widespread. This type of anaesthesia could result in a higher incidence of implicit memory.

Methods: Ten patients were anaesthetised with a target-controlled infusion of remifentanil (target concentration of 8 ng mL−1) combined with a target-controlled infusion of propofol with progressive stepwise increases until loss of consciousness was reached. A tape containing 20 words was then played to the patients. Bispectral index (BIS, Aspect Medical Systems, Newton, MA, USA) was continuously monitored during the whole study period. Implicit and explicit memories were tested between 2 and 4 h after recovery.

Results: Loss of consciousness was obtained with a mean calculated propofol plasma concentration of 1.3 ± 0.4 μg mL−1. At this low hypnotic concentration no implicit or explicit memory was found in the three postoperative memory tests. Median (range) BIS value during word presentation was 93 (80–98).

Conclusions: In our group of young American Society of Anesthesiologists (ASA) I/II patients, no explicit or implicit memory was found when the calculated concentration of propofol combined with a high concentration of remifentanil was maintained at the level associated with loss of consciousness with high BIS values.

Summary

Background and objectives: This randomized controlled trial was designed to evaluate, first, whether intra- or postoperative music therapy could influence stress and immune response during and after general anaesthesia and second, if there was a different response between patients exposed to music intra- or postoperatively.

Method: Seventy-five patients undergoing open hernia repair as day care surgery were randomly allocated to three groups: intraoperative music, postoperative music and silence (control group). Anaesthesia and postoperative analgesia were standardized and the same surgeon performed all the operations. Stress response was assessed during and after surgery by determining the plasma cortisol and blood glucose levels. Immune function was evaluated by studying immunoglobulin A (IgA) levels. Patients' postoperative pain, anxiety, blood pressure (BP), heart rate (HR) and oxygen saturation were also studied as stress markers.

Results: There was a significantly greater decrease in the level of cortisol in the postoperative music group vs. the control group (206 and 72 mmol L−1 decreases, respectively) after 2 h in the post anaesthesia care unit. The postoperative music group had less anxiety and pain and required less morphine after 1 h compared with the control group. In the postoperative music group the total requirement of morphine was significantly lower than in the control group. The intraoperative music group reported less pain after 1 h in the post anaesthesia care unit. There was no difference in IgA, blood glucose, BP, HR and oxygen saturation between the groups.

Conclusion: This study suggests that intraoperative music may decrease postoperative pain, and that postoperative music therapy may reduce anxiety, pain and morphine consumption.

Summary

Background and objective: Patients having spinal anaesthesia with hyperbaric bupivacaine may become sensitive to sedative drugs but no data exists about any dose-related effect of the local anaesthetic on the sedative requirement. We aimed to investigate whether hyperbaric bupivacaine dose in spinal anaesthesia has any effect on midazolam requirements. Methods: Sixty unpremedicated patients were allocated to three equal groups. Patients in Groups I and II received hyperbaric bupivacaine 0.5% 10 and 17.5 mg respectively for spinal anaesthesia and Group III was a control group without spinal anaesthesia. In Groups I and II, after the evaluation of sensory block, patients received intravenous midazolam 1 mg per 30 s until the Ramsay sedation score reached 3 (drowsy but responsive to command). In Group III, general anaesthesia was induced after sedation score had reached 3 using midazolam. The total dose of midazolam (mg kg−1) given to each patient, the level of sensory block and complications were recorded. Results: The level of sensory block was higher in Group II (T7) than Group I (T9) (P < 0.01). The doses of midazolam were 0.063 mg kg−1 in Group I, 0.065 mg kg−1 in Group II and 0.101 mg kg−1 in Group III (P < 0.001). There was no correlation between level of sensory block and dose of midazolam in Group I (r = −0.293, P = 0.21) and Group II (r = 0.204, P = 0.39). Conclusions: Different doses of hyperbaric bupivacaine for spinal anaesthesia do not affect the midazolam requirements for sedation. However, spinal anaesthesia with hyperbaric bupivacaine with a maximum spread in the middle thoracic dermatomes may be associated with sedative effects and thus a reduced need for further sedation with midazolam.

Summary

Background and objective: Reducing postoperative mechanical ventilation in patients undergoing liver transplantation may have clinical and organizational advantages. On the basis of our experience, we here evaluate the possibility of practising immediate tracheal extubation in the operating theatre. Methods: In this prospective study, patients consecutively undergoing liver transplantation between 1 June 1999 and 31 May 2004 were extubated in the operating theatre at the end of surgery on the basis of standardized and universally accepted criteria, under conditions of haemodynamic and metabolic stability. Results: Two hundred and seven of the 354 patients (58.5%) were extubated immediately after the completion of the surgical procedure (mean time between end of surgery and extubation: 0.4 ± 1.4 min); two were re-intubated. In the last of the 5 yr of the study, the percentage of immediate extubations increased to 82.5%. During the study period, there was a progressive increase in the number of immediate extubations per individual member of the team of anaesthetists. The pre-transplant Child-Pugh severity of the underlying liver disease did not predict rapid extubation, but the Model for End-stage Liver Disease score of <11 did (receiver operator characteristic area under the curve = 0.61; P < 0.05). Conclusions: Immediate extubation after liver transplantation is possible in a substantial percentage of cases; confidence, habit and a spirit of emulation are decisive factors in encouraging anaesthetists to extend this practice to the largest possible number of patients. A successful immediate extubation may be an important indicator of perioperative quality of care in liver transplantation.

Summary

Background and objective: Previous studies mainly conducted on elective patients recommend doses of 0.9–1.2 mg kg−1 rocuronium to obtain comparable intubation conditions with succinylcholine 1.0 mg kg−1 after 60 s during a rapid-sequence induction. We decided to compare the overall intubating conditions of standard doses of rocuronium 0.6 mg kg−1 and succinylcholine 1.0 mg kg−1 during a strict rapid-sequence induction regimen including propofol and alfentanil. Methods: Male and female patients (ASA I–III) older than 17 yr scheduled for emergency abdominal or gynaecological surgery and with increased risk of pulmonary aspiration of gastric content were randomized to a rapid-sequence induction with succinylcholine 1.0 mg kg−1 or rocuronium 0.6 mg kg−1. Patients with a predicted difficult airway were excluded. A senior anaesthesiologist ‘blinded’ for the randomization performed the intubation 60 s after injection of the neuromuscular blocker. Intubating conditions were evaluated according to an established guideline. Tracheal intubation not completed within 30 s was recorded as failed. Results: 222 patients were randomized. Three patients had their operation cancelled and 10 did not fulfil the inclusion criteria. Clinically acceptable intubation conditions were present in 93.5% and 96.1% of patients in the succinylcholine group (n = 107) and the rocuronium group (n = 102), respectively (P = 0.59). Conclusions: During a rapid-sequence induction with alfentanil and propofol, both rocuronium 0.6 mg kg−1 and succinylcholine 1.0 mg kg−1 provide clinically acceptable intubation conditions in 60 s in patients scheduled for emergency surgery. Under the conditions of this rapid-sequence induction regimen rocuronium may be a substitute for succinylcholine.

Summary

Background and objective: Cardiopulmonary resuscitation should not be interrupted until the return of spontaneous circulation or the decision to withhold further treatment. There are no data on how consistent in-hospital cardiopulmonary resuscitation is performed. Accordingly, the aim of the present study was to identify length and type of unnecessary interruptions in simulated cardiac arrests. Methods: The study was carried out in a patient simulator. A scenario of cardiac arrest due to ventricular fibrillation was used. Resuscitation teams consisted of three nurses, a resident and a staff physician. Using videotapes recorded during simulations, the activities of the teams were coded in 5-s intervals. Unnecessary interruptions were defined as any interruptions in cardiac massage of 10 s or more that were not caused by defibrillation or endotracheal intubation. Results: Twelve teams were studied. The total time of possible cardiac massage was 414 ± 125 s. In each team at least one unnecessary interruption occurred (range 1–5). Interruptions mounted up to 65 ± 40 s (range 20–155) or 16 ± 10% (range 5–41) of the total time of possible cardiac massage. Failure to swiftly resume cardiac massage after an unsuccessful defibrillation accounted for 14 of 39 episodes and for 44 ± 40% of the time of unnecessary interruptions. The debriefings revealed that participants had generally not noticed the unnecessary interruptions during the simulation. Conclusions: The present study identified a significant amount of unnecessary interruptions in cardiac massage. These interruptions were not noticed by the health-care workers involved.

Summary

Background: In myasthenic patients, the time course of action of non-depolarizing neuromuscular blocking agents is prolonged and the sensitivity is increased. We used our antegrade perfused rat peroneal nerve anterior tibialis muscle model to investigate if this altered time course of effect and sensitivity can be explained by the decreased acetylcholine receptor concentration that is caused by the disease. Methods: Functional acetylcholine receptors were reduced by administration of α-bungarotoxin or by injecting monoclonal antibodies against rat acetylcholine receptors (experimental autoimmune myasthenia gravis). After induction of anaesthesia, the model was set up and perfusion of the tibialis anterior muscle with blood was started. After stabilization of the twitch, rocuronium or pancuronium were infused until 90% block was obtained. Twitch data and infusion data were recorded and used to calculate the time course of effect and potency. Results: The potency of neuromuscular blocking agents was increased and the offset of the neuromuscular block was prolonged in both the α-bungarotoxin groups and the experimental autoimmune myasthenia gravis groups compared to controls. Conclusion: This study shows that the increased sensitivity to neuromuscular-blocking agents in myasthenia gravis can be accounted for by a decreased number of acetylcholine receptors. It also shows that the antegrade perfused rat peroneal nerve anterior tibialis muscle model is a suitable model to study the effects of myasthenia gravis on the time course of effect of neuromuscular blocking agents.