Summary

Recent articles published in peer review journals have questioned the safety of using aprotinin in patients having heart surgery. Also, evidence has been published to suggest an increase in renal events in patients given aprotinin when compared to those where tranexamic acid was used. The present review will focus principally on the first of these articles in relation to previously published data and experience.

Summary

Background and objectives: This study was undertaken to compare the effect of alpha-stat vs. pH-stat strategies for acid–base management on regional cerebral oxygen saturation (RsO2) in patients undergoing moderate hypothermic haemodilution cardiopulmonary bypass (CPB). Methods: In 14 adult patients undergoing elective coronary artery bypass grafting, an awake RsO2 baseline value was monitored using a cerebral oximeter (INVOS 5100). Cerebral oximetry was then monitored continuously following anaesthesia and during the whole period of CPB. Mean ± SD of RsO2, CO2, mean arterial pressure and haematocrit were determined before bypass and during the moderate hypothermic phase of the CPB using the alpha-stat followed by pH-stat strategies of acid–base management. Alpha-stat was then maintained throughout the whole period of CPB. Results: The mean baseline RsO2 in the awake patient breathing room air was 59.6 ± 5.3%. Following anaesthesia and ventilation with 100% oxygen, RsO2 increased up to 75.9 ± 6.7%. Going on bypass, RsO2 significantly decreased from a pre-bypass value of 75.9 ± 6.7% to 62.9 ± 6.3% during the initial phase of alpha-stat strategy. Shifting to pH-stat strategy resulted in a significant increase of RsO2 from 62.9 ± 6.3% to 72.1 ± 6.6%. Resuming the alpha-stat strategy resulted in a significant decrease of RsO2 to 62.9 ± 7.8% which was similar to the RsO2 value during the initial phase of alpha-stat. Conclusion: During moderate hypothermic haemodilutional CPB, the RsO2 was significantly higher during the pH-stat than during the alpha-stat strategy. However, the RsO2 during pH-stat management was significantly higher than the baseline RsO2 value in the awake patient breathing room air, denoting luxury cerebral perfusion. In contrast, the RsO2 during alpha-stat was only slightly higher than the baseline RsO2, suggesting that the alpha-stat strategy avoids luxury perfusion, but can maintain adequate cerebral oxygen supply-demand balance during moderate hypothermic haemodilutional CPB.

Summary

Background and objective: Cardiopulmonary bypass is associated with temperature pertubations that influence extubation time. Common extubation criteria demand a minimum value of core temperature only. The aim of this prospective study was to test the hypothesis that changes in core and skin surface temperature are related to extubation time in patients following normothermic and hypothermic cardiopulmonary bypass. Methods: Forty patients undergoing cardiac surgery were studied; 28 patients had normothermic cardiopulmonary bypass (nasopharyngeal temperature >35.5°C) and 12 had hypothermic cardiopulmonary bypass (28–34°C). In the intensive care unit, urinary bladder temperature and skin surface temperature gradient (forearm temperature minus fingertip temperature: >0°C =vasoconstriction, ≤0°C =vasodilatation) were measured at 30-min intervals for 10 h postoperatively. At the same intervals, the patients were evaluated for extubation according to common extubation criteria. Results: On arrival in the intensive care unit the mean urinary bladder temperature was 36.8 ± 0.5°C in the normothermic group and 36.4±0.3°C in the hypothermic group ( P = 0.014). The skin surface temperature gradient indicated severe vasoconstriction in the both groups. The shift from vasoconstriction to vasodilatation was faster in normothermic cardiopulmonary bypass patients (138±65 min) than in patients after hypothermic cardiopulmonary bypass (186±61 min, P = 0.034). There was a linear relation between the time to reach a skin surface temperature gradient = 0°C and extubation time (r2 = 0.56, normothermic group; r2 = 0.82, hypothermic group). Conclusions: The transition from peripheral vasoconstriction to vasodilatation is related to extubation time in patients following cardiac surgery under normothermic as well as hypothermic cardiopulmonary bypass.

Summary

Background: To evaluate the myocardial protective effect of nicorandil when used as an adjuvant to cold hyperkalaemic cardioplegia in open-heart surgery. Methods: Patients who underwent surgery under cardiopulmonary bypass (CPB) for mitral valve replacement (MVR, 23 patients) or coronary artery bypass grafting (CABG, 24 patients) were entered in a double-blind study. The patients were randomized to a nicorandil Group (N) or placebo Group (P). Nicorandil 0.1 mg kg−1 (Group N), or normal saline (Group P), were administered at three time points: (1) after aortic cannulation, but prior to going on CPB, (2) 5 min before aortic cross-clamping and (3) 5 min before reperfusion. The following variables were studied: (a) time until electromechanical arrest after cardioplegia administration (Tarrest), (b) time until return of electromechanical activity after aortic cross-clamp removal (Trecovery), (c) incidence of postoperative myocardial infarction or low output syndromes (d) dysrhythmias requiring intervention after aortic cross-clamp removal and (e) haemodynamic changes after nicorandil administration. Results: The Tarrest after cardioplegia administration was significantly faster in nicorandil group in both MVR and CABG patients (P < 0.05), but Trecovery did not differ significantly. The incidence of postoperative serum CK-MB > 75 IU L−1 in MVR patients was significantly lower in the Group N than in placebo patients (P < 0.05). However, in CABG patients there was no such significant difference. The incidence of dysrhythmias requiring intervention after aortic cross-clamp removal was also less in Group N. Administration of 0.1 mg kg−1 boluses of nicorandil did not cause significant haemodynamic changes or precipitate dysrhythmias in any patient. Conclusion: Nicorandil enhances the myocardial protective effect of cold hyperkalaemic cardioplegia in cardiac surgery patients.

Summary

Background and objective: Previous studies found that lidocaine addition to propofol long-chain triglyceride was associated with a lower incidence of injection pain than medium-chain triglyceride/long-chain triglyceride formulation, but the incidence was still high (31–40%). Our study investigated whether the incidence of injection pain could be further reduced by the addition of lidocaine (10 mg, 20: 1) to propofol medium-chain triglyceride/long-chain triglyceride. Methods: In a randomized double-blind controlled trial 464 patients scheduled to undergo regional anaesthesia were assigned to receive one of the following four options: propofol medium-chain triglyceride/long-chain triglyceride + lidocaine, propofol long-chain triglyceride +lidocaine, propofol medium-chain triglyceride/long-chain triglyceride or propofol long-chain triglyceride. Propofol was injected to reach grade 3 of the Observer’s Assessment of Alertness/Sedation scale. Results: Incidence of injection pain was 18% in the propofol medium-chain triglyceride/long-chain triglyceride +lidocaine group, 31% in the propofol long-chain triglyceride +lidocaine group, 47% in the propofol medium-chain triglyceride/long-chain triglyceride group and 60% in the long-chain triglyceride group. Propofol medium-chain triglyceride/long-chain triglyceride + lidocaine was associated with a statistically significant reduced incidence of injection pain compared with propofol long-chain triglyceride +lidocaine ( P =0.0249, number needed to treat =7.7). Conclusions: Premixing propofol medium-chain triglyceride/long-chain triglyceride with lidocaine is one of the most effective measures currently available to reduce the incidence of injection pain in sedated patients during regional anaesthesia.

Summary

Background and objectives: Autonomic circulatory regulation and airway anatomy in children are significantly different from those in adults. There is no available published data to compare whether there is a clinically relevant difference in the haemodynamic responses to fibreoptic orotracheal intubation (FOI) under the same conditions between children and adults. In this randomized clinical study, we compared the blood pressure (BP) and heart rate (HR) changes during FOI in 40 children aged 3.5–9 yr and 40 adults aged 21–57 yr, ASA 1 scheduled for elective plastic surgery under general anaesthesia requiring orotracheal intubation. Methods: Anaesthesia was induced with intravenous (i.v.) injection of fentanyl and propofol, and face mask inhalation of isoflurane before FOI. Noninvasive BP and HR were recorded before induction (baseline values), after induction (postinduction values), at intubation and for 5 min after intubation at 1-min intervals. The percentage changes of BP and HR at each time point were calculated. Results: In children and adults, HR at intubation and 1–3 min after intubation were significantly higher than baseline and postinduction values. In adults, BP at intubation increased significantly compared to the postinduction values but did not exceed baseline values. In children, BP at intubation and 1 min after intubation were significantly higher than postinduction and baseline values. As compared to adults, FOI caused a more significant pressor response in children. The percentage changes of BP at intubation and 1 min after intubation were larger in children than in adults. However, there was no significant difference in the percentage change of HR during the observation between children and adults. Conclusions: Under general anaesthesia, FOI might cause a more significant pressor response in children than in adults.

Summary

Background and objectives: Apoptosis occurs after thermal injury and may result from either ischaemic intestinal insult or inflammatory mediators released after burn injury. The aim of the study was to investigate the effects of propofol and ketamine on gut epithelium apoptosis after burn injury. Methods: Sixty male Wistar Albino rats were randomly assigned into four groups. Anaesthesia was induced and maintained with propofol in Groups 1 and 2, and ketamine in Groups 3 and 4 over 12 h. Groups 2 and 4 received 30% total body surface area burn. Groups 1 and 3 had no burn injury. Mean arterial pressure was maintained within 10% of baseline levels in all animals. At 12 h postburn, animals were sacrificed and tissue samples were taken from small intestine for determination of lipid peroxidation, apoptosis and proliferation. Also blood samples were taken for measurement of serum tumor necrosis factor-alpha (TNF-α) levels. Results: Ileal malondialdehyde (MDA) concentration (extent of lipid peroxidation) increased significantly in Group 4 (112.4 ± 10.2 nmol g−1) compared to Group 3 (48.4 ± 5.6 nmol g−1) and Group 2 (59.8 ± 3.2 nmol g−1). The mean TNF-α level in Group 4 (118.9 ± 10.5 pg mL−1) at 12 h postburn was significantly higher than the mean in Group 2 (56.4 ± 4.3 pg mL−1). Group 4 had the highest mean TUNEL index (terminal deoxyuridine nick-end labelling – an index of extent of apoptosis) of all the groups (265/10). Also the mean TUNEL index value in Group 2 (53/10) was higher than that of Group 1 (3/10) and Group 3 (5/10). The proliferating cell nuclear antigen index (extent of proliferation) remained unchanged among groups. Conclusions: Propofol could offer a protection against apoptosis of enterocytes with a stable tissue MDA and serum TNF-α level compared to ketamine anaesthesia in an animal model of burn injury.

Summary

Background and objective: To evaluate the different potencies of several opioids in obtunding reflex mechanisms of laryngoscopy and intubation. Methods: Three groups of patients (each n = 25, ASA 1–2) undergoing elective plastic surgery were randomly given meptazinol (2.5 mg kg−1 ), nalbuphine (0.3 mg kg−1) or fentanyl (5 μg kg−1) in a blinded fashion prior to laryngoscopy and intubation. This was followed by a standardized bolus induction of a barbiturate and a muscle relaxant. The response to laryngoscopy and intubation was studied, using blood pressure, heart rate and bispectral index. Results: With fentanyl, there was an increase of heart rate by 17%, and systolic blood pressure by 7% when compared to control. Bispectral index dropped an additional 8% when compared to 1 min after barbiturate induction. In the nalbuphine group there was a 16% increase in systolic blood pressure, and a 16% increase in heart rate when compared to control. Also, bispectral index increased by 18% when compared to 1 min after barbiturate injection. The group receiving meptazinol demonstrated no cardiovascular changes although bispectral index dropped by an additional 19% when compared to 1 min after barbiturate injection. Conclusion: Meptazinol, appears to depress cardiovascular stimulatory effects and electroencephalogram arousal induced by laryngoscopy and intubation better than nalbuphine or fentanyl.

Summary

Background and objectives: The aim of this prospective, observational study was to evaluate changes in regional cerebral oxygen saturation (rSO2) and incidence of intraoperative cerebral desaturation in a cohort of elderly patients undergoing major abdominal surgery. Methods: rSO2 was continuously monitored on the left and right sides of the forehead in 60 patients older than 65 yr (35 males and 25 females; ASA II–III; age: 72 ± 5 yr; without pre-existing cerebral pathology, and baseline Mini Mental State Examination (MMSE) score >23) undergoing sevoflurane anaesthesia for major abdominal, non-vascular surgery >2 h. Results: Baseline rSO2 was 63 ± 8%; cerebral desaturation (rSO2 decrease <75% of baseline or <80% in case of baseline rSO2 <50%) occurred in 16 patients (26%). The MMSE decreased from 28 ± 1 before surgery to 27 ± 2 on 7th postoperative day (P = 0.05). A decline in cognitive function (decrease in MMSE score ≥ 2 points one week after surgery as compared to baseline value) was observed in six patients without intraoperative cerebral desaturation (13.6%) and six patients who had intraoperative cerebral desaturation (40%) (P = 0.057) (odds ratio: 4.22; CI95%: 1.1–16). Median (range) hospital stay was 14 (5–41) days in patients with an area under the curve of rSO2 <50% (AUCrSO2<50%) >10 min%, and 10 (4–30) days in those with an AUCrSO2<50% <10 min% (P = 0.0005). Conclusions: In a population of healthy elderly patients, undergoing non-vascular abdominal surgery cerebral desaturation can occur in up to one in every four patients, and the occurrence of cerebral desaturation is associated with a higher incidence of early postoperative cognitive decline and longer hospital stay.

Summary

Background and objective: For many, the administration of additional oxygen to the women receiving regional anaesthesia for Caesarean section is traditional, but for others it is controversial because of doubts about its efficacy. The aim of our study was to determine if beneficial effects of maternal oxygen therapy on the fetus could be revealed using a neonatal behavioural scoring system. Methods: Sixty women with a normal singleton pregnancy beyond 36 weeks gestation, undergoing elective Caesarean section under spinal anaesthesia were randomized into two groups: Group 1 received air and oxygen mixture through a Hudson style face mask (FiO2 of 0.21–0.25). Group 2 received FiO2 of 0.40–0.60 through an identical Hudson style face mask. Neurologic Adaptive Capacity Score on all the infants within 5 min of birth and between 10 and 24 h after the Caesarean delivery was performed. Apgar score, umbilical venous blood oxygen tension and umbilical artery standardized base excess were recorded. Results: Initial Neurologic Adaptive Capacity Scores at birth in Groups 1 and 2 were 32.6 (SD 4.6) and 31.3 (SD 4.3), respectively. Latter scores were 36.0 (SD 3.0) and 36.5 (SD 1.9), respectively. Neither were statistically significant. There were no significant differences between the groups for any of the recorded variables. Conclusions: Administering maternal oxygen using a standard commercial Hudson style face mask does not appear to significantly improve oxygen delivery to, nor does it influence acidosis or behavioural effects in, the normal neonate at elective Caesarean delivery with spinal anaesthesia.

Summary

Background and objective: National Institute for Clinical Excellence guidance states that 2D imaging ultrasound guidance should be used when inserting internal jugular venous lines in adults and children in the elective situation and should be considered in most clinical circumstances requiring central venous catheter insertion. This survey explored the availability, training and use of ultrasound devices by consultant paediatric anaesthetists in the UK. Methods: A questionnaire was distributed to UK members of the Association of Paediatric Anaesthetists of Great Britain and Ireland. Results: There was a response rate of 63% and of those responding, 212 (81%) inserted paediatric central venous catheters. Ultrasound devices were available in the workplace of 216 (82%) and the average number of devices available per department was two. For elective paediatric theatre cases, 26% of paediatric anaesthetists with access to an ultrasound device always used it when inserting an internal jugular central venous line. The majority (74%) of respondents had received training in the use of 2D ultrasound. Conclusions: National Institute for Clinical Excellence guidance on the use of ultrasound locating devices for placing central venous catheters is not universally adhered to. Among the reasons for this are problems with availability of equipment, lack of training in the use of ultrasound and non-acceptance of the guidelines.

Summary

Background and objective: The Eschmann multiple-use introducer is widely used in the management of difficult intubations. Transillumination of the neck is less commonly used. We conducted a randomized crossover study comparing the Trachlight® lightwand and Eschmann multiple-use introducer in simulated difficult intubation. Methods: Sixty-four healthy patients were studied using a standard anaesthetic and full muscle relaxation assessed by train of four. A Macintosh laryngoscope was then inserted and then lowered to simulate a Grade 3 view. Tracheal placement was attempted with both Trachlight® lightwand and Eschmann multiple-use introducer in a randomized order. Anaesthetists placing the devices had extensive experience with the Eschmann multiple-use introducer, but only 15 previous uses of the Trachlight®. Success rates and time for tracheal placement were recorded. Results: The Eschmann multiple-use introducer and Trachlight® were successfully placed in 96.8% and 93.7%, respectively (n.s.). Mean (SD) time to intubation for Eschmann multiple-use introducer and Trachlight® were 15(6) and *21(13), respectively (*P < 0.001). Conclusion: The Trachlight® is a potentially useful alternative to the Eschmann multiple-use introducer in difficult intubation.

Summary

Introduction: The influence of the twitch height of the adductor pollicis muscle during baseline measurements on the pharmacodynamic parameters of mivacurium was prospectively evaluated. Patients and methods: Fifty adult patients were anaesthetized with propofol and alfentanil. Neuromuscular function was monitored mechanomyographically by measuring the force of the adductor pollicis muscle following stimulation of the ulnar nerve. Following a stabilization period of 20 min, the individual twitch height of the adductor pollicis muscle was determined before a single bolus of mivacurium (75 μg kg−1) was administered. Patients were divided into two groups. The data of patients whose thumb adduction force was below the median value of all patients were the ‘low force’ group (9.1 ± 1.4 N) and the data of all other patients were the ‘high force’ group (13.7 ± 1.8 N). Results: In the ‘high force’ group, maximum neuromuscular blockade of mivacurium was deeper (0.97 ± 0.05 vs. 0.93 ± 0.06; P < 0.05) and onset faster (2.9 ± 1.1 min vs. 4.0 ± 1.2 min; P < 0.05). Neuromuscular recovery did not differ between the groups. Conclusion: The different onset speeds reflect either different sensitivity to neuromuscular blocking agents with respect to patients' muscle power or a problem of the mechanomyographic measuring technique.

Summary

Background and objectives: To evaluate the effectiveness of acupressure in preventing nausea and vomiting in patients undergoing gynaecological operations and receiving a patient-controlled analgesia device. Methods: Patients aged between 40 and 65 yr were included. Exclusion criteria were obesity, diabetes mellitus, and history of motion sickness, postoperative nausea and vomiting, or smoking. Patients were randomized into one of two groups, acupressure and control. In the acupressure group, acupressure bands were placed on both wrists with the plastic bead positioned at the P6 point. In controls, beads were placed at a non-acupoint site. All patients received a standard general anaesthetic. Postoperatively, patients were connected to a patient-controlled analgesia device with morphine (loading dose 5 mg, background infusion 1 mg h−1, bolus dose 1 mg and lock-out time 10 min). Pain and sedation scores, respiratory rate, heart rate, arterial pressure and oxygen saturation were recorded for 24 h. Metoclopramide 10 mg was administered intravenously as a rescue antiemetic. Results: Fifty patients received acupressure and 50 were controls. In the acupressure group, 33% of patients had nausea compared with 63% controls. The cumulative incidence of vomiting at 24 h was 25% with acupressure and 61% in controls. The incidence of nausea, vomiting and antiemetic use was significantly lower with acupressure. Conclusions: Acupressure at the P6 meridian point is an effective alternative for the prevention of nausea and vomiting in patients receiving patient-controlled analgesia with morphine after gynaecological surgery.