A number of prospective randomized comparator studies have suggested that there is a reduction in post-operative nausea and vomiting following maintenance of anaesthesia with propofol compared with inhalational agents. We analysed these studies in more detail by examining the effects of induction agent, choice of inhalation agent, presence/absence of nitrous oxide, age of patient or use of opiate on the incidence of emesis. A search of the Zeneca database MEDLEY was undertaken and prospective randomized comparator studies identified. These were examined individually and independently by two of the authors and log-odds ratios, calculated from the incidence data of each individual trial, were determined and combined using a fixed-effects meta-analysis approach. Patients who received maintenance of anaesthesia with propofol had a significantly lower incidence of post-operative nausea and vomiting in comparison with inhalational agents regardless of induction agent, choice of inhalation agent, presence/absence of nitrous oxide, age of patient or use of opiate.

Summary

Background and objective: Sore throat and hoarseness rank, besides pain and nausea, among the most frequent subjective complaints after tracheal intubation for general anaesthesia. Our intention was to determine the incidence of postoperative sore throat from a large sample of patients and thus to identify the most important associated factors.

Methods: We prospectively followed up 809 adult patients who underwent elective surgical interventions and examined their history, the applied anaesthetic techniques, perioperative course and the occurrence, intensity and duration of postoperative throat complaints. The assignment and professional experience of the involved intubators were also assessed. The influence of a multitude of variables on postoperative throat complaints was statistically analysed.

Results: Postoperative sore throat was present in 40% overall being significantly higher in female than in male (44% vs. 33%; P = 0.001). The mean pain intensity in the affected patients (n = 323) was 28 ± 12 mm on a visual analogue scale where 0 = no pain and 100 = extreme pain. The average duration was 16 ± 11 h. Main factors associated with throat complaints were female sex, history of smoking or lung disease, duration of anaesthesia, postoperative nausea, bloodstain on the endotracheal tube and natural teeth. We could find no influence on the occurrence or intensity of throat complaints by the professional assignment or the length of professional experience of the personnel involved.

Conclusions: Postoperative throat complaints frequently arise after tracheal intubation for general anaesthesia in the first 2 postoperative days, but they are of limited intensity and duration.

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: In small children, the placement of arterial catheters can be technically challenging for even the most experienced anaesthetist. We investigated whether ultrasound imaging would improve the success rate and reduce time demand and complications of radial artery cannulation. Method: In this prospective randomized study, we performed radial artery cannulation in 30 small children (age 40 ± 33 months) using two different techniques for localization of the vessel. In Group 1 (n = 15), the traditional palpation method was used, while in Group 2 (n = 15) cannulation was directed by vascular ultrasound imaging. In addition, we used ultrasound to determine the cross-sectional area of the radial artery with and without dorsiflexion. For statistical analysis, the non-parametric U-test for non-paired data and the Wilcoxon signed rank sum test for paired data were used. Differences were considered significant, when P < 0.05. Results: Ultrasound-guided puncture was successful in all children of Group 2 compared to only 12 of 15 (80%) children in Group 1. Fewer attempts with the imaging technique were required than with the traditional technique (20 vs. 34, P < 0.05). Dorsiflexion significantly reduced the mean cross-sectional area of the artery by 19%. Conclusion: The current pilot study suggests that ultrasound guidance is appropriate for radial artery catheter insertion, sharing many of the benefits of ultrasound-guided central vein catheter insertion.

In the long term after traumatic brain injury, the most disabling problems are generally related to neuropsychiatric sequelae, including personality change and cognitive impairment, rather than neurophysical sequelae. Cognitive impairment after severe injury is likely to include impaired speed of information processing, poor memory and executive problems. Personality change may include poor motivation, and a tendency to be self-centred and less aware of the needs of others. Patients may be described as lazy and thoughtless. Some become disinhibited and rude. Agitation and aggression can be very difficult to manage. Anxiety and depression symptoms are quite frequent and play a role in the development of persistent post-concussion syndrome after milder injury. Depression may be associated with a deterioration in disability over time after injury. Psychosis is not unusual though it has been difficult to confirm that traumatic brain injury is a cause of schizophrenia. Head injury may, many years later, increase the risk of Alzheimer’s disease. Good rehabilitation probably minimizes the risk of psychiatric sequelae, but specific psychological and pharmacological treatments may be needed.

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

Background and objective: Preoperative epoetin alfa administration decreases transfusion requirements and may reduce transfusion complications, such as postoperative infection due to immune suppression and thus hospitalization time. This study examined the impact of preoperative epoetin alfa administration on postoperative recovery and infection rate.

Methods: In an open randomized controlled multicentre trial in patients undergoing orthopaedic surgery, the effects of preoperative administration of epoetin alfa vs. routine care were compared in six countries. Haemoglobin (Hb) values, transfusions, time to ambulation, time to discharge, infections and safety were evaluated in patients with preoperative Hb concentrations 10–13g dL−1 (on-treatment population: epoetin n = 460; control n = 235), from study entry until 4–6 weeks after surgery. Outcome was also compared in patients with and without transfusion.

Results: Epoetin-treated patients had higher Hb values from the day of surgery until discharge (P < 0.001) and lower transfusion rates (12% vs. 46%; P < 0.001). Epoetin treatment delivered no significant effect on postoperative recovery (time to ambulation, time to discharge and infection rate). However, the time to ambulation (3.8 ± 4.0 vs. 3.1 ± 2.2 days; P < 0.001) and the time to discharge (12.9 ± 6.4 vs. 10.2 ± 5.0 days; P < 0.001) was longer in the transfused than in the non-transfused patients. Side-effects in both groups were comparable.

Conclusions: Epoetin alfa increases perioperative Hb concentration in mild-to-moderately anaemic patients and thus reduces transfusion requirements. Patients receiving blood transfusions require a longer hospitalization than non-transfused patients.

Summary

Background and objective: This prospective, randomized, double-blind, controlled study was designed to test the effect of pre-anaesthetic administration of dexmedetomidine, given as a single intravenous (i.v.) dose, on postoperative pain scores and morphine consumption in patients receiving patient-controlled morphine after abdominal surgery.

Methods: Sixty patients were randomly allocated to receive dexmedetomidine (1 μg kg−1) or saline 10 min before induction of anaesthesia. Twenty minutes before the end of surgery, all patients received a standardized (0.1 mg kg−1) loading dose of morphine. They were then allowed to use a patient-controlled analgesia (PCA) device giving bolus doses of morphine (0.02 mg kg−1). Pain, discomfort and sedation scores; cumulative morphine consumption; time to extubation; time to recovery; and any side-effects were recorded after recovery and at 1, 2, 6, 12 and 24 h after the start of PCA.

Results: The mean time to extubation at the end of anaesthesia and recovery time were similar in both groups. There were no significant differences between groups with regard to mean pain, discomfort, sedation and nausea scores. Cumulative morphine consumption was significantly lower in the dexmedetomidine group at 6, 12 and 24 h (P < 0.05). The incidence of side-effects did not differ between the groups.

Conclusions: A single i.v. dose of dexmedetomidine (1 μg kg−1) given 10 min before induction of anaesthesia significantly reduced postoperative morphine consumption at identical pain scores compared to control, but had no effect on postoperative recovery time.

Anaphylactic reactions to anaesthetic and associated agents used during the perioperative period have been reported with increasing frequency in most developed countries. Any drug administered in the perioperative period can potentially produce life-threatening immune-mediated anaphylaxis. Most published reports on the incidence of anaphylaxis come from France, Australia, the UK and New Zealand. These reflect an active policy of systematic clinical and/or laboratory investigation of suspected immune-mediated reactions. The estimated incidence of anaphylaxis ranges from 1 : 10 000 to 1 : 20 000. Muscle relaxants (69.1%) and latex (12.1%) were the most frequently involved drugs according to the most recent French epidemiological survey. Clinical symptoms do not afford an easy distinction between immune-mediated anaphylactic reactions and anaphylactoid reactions resulting from direct non-specific histamine release. Moreover, when restricted to a single clinical symptom, anaphylaxis can easily be misdiagnosed. Pre- and postoperative investigation must be performed to confirm the nature of the reaction, the responsibility of the suspected drugs and to provide precise recommendations for future anaesthetic procedures. These include plasma histamine, tryptase and specific IgE concentration determination at the time of the reaction and at skin tests 6 weeks later. In addition, since no specific treatment has been shown reliably to prevent the occurrence of anaphylaxis, allergy assessment must be performed in all high-risk patients. Treatment of anaphylaxis is aimed at interrupting contact with the responsible antigen, inhibiting mediator production and release, and modulating the effects of released mediators. It must be initiated as quickly as possible and relies on widely accepted principles. Finally, the need for proper epidemiological studies and the relative complexity of allergy investigation should be underscored. They represent an incentive for further development of allergo-anaesthesiology clinical networks to provide expert advice for anaesthetists and allergologists.

Background and objective Numerous drugs have been used to prevent or to treat opioid-induced pruritus in the surgical setting. Their relative efficacy is not well understood.

Methods The methods employed involved the systematic search (MEDLINE, EMBASE, Cochrane library, bibliographies, without language restriction, up to June 2000) for full reports of randomized comparisons of any intervention which is thought to be anti–pruritic (active) compared with placebo or no treatment (control) in surgical (including labour) patients receiving opioids. The number of patients who had no pruritus were analysed using relative risk and number–neededto– treat with 95% confidence interval.

Results Twenty-two trials (1477 patients) were analysed. Two trials (66 patients), both with low-dose propofol, were on treatment of established pruritus; propofol had no anti-pruritic effect compared with Intralipid. In prophylaxis trials, the average incidence of pruritus with control was 59% (range, 10% to 100%). Most mu–receptor antagonists were efficacious: intravenous naloxone 0.25–2.4 μgkg−1 h−1, relative risk 2.31 (95% confidence interval, 1.5 to 3.54), numberneeded– to–treat to prevent pruritus compared with control 3.5; oral naltrexone 9 mg, relative risk 2.80 (1.35–5.80), number-needed-to-treat 1.7; naltrexone 6mg was less effective and 3mg did not work; different intravenous and epidural nalbuphine regimens, relative risk 1.71 (1.12–2.62), number-needed-to-treat 4.2. Intravenous nalmefene 0.5 or 1mg was not antipruritic. Intravenous (but not epidural) droperidol 2.5mg was efficacious, relative risk, 1.71 (1.28–2.29), number-needed-to-treat 4.9. There was a lack of evidence for any anti–pruritic efficacy with prophylactic propofol, epidural or intrathecal epinephrine, epidural clonidine, epidural prednisone, intravenous ondansetron, or intramuscular hydroxyzine.

Conclusion Naloxone, naltrexone, nalbuphine and droperidol are efficacious in the prevention of opioidinduced pruritus; minimal effective doses remain unknown. There is a lack of valid data on the efficacy of interventions for the treatment of established pruritus.

Summary

Background and objectives: Colloids such as hydroxyethyl starch (HES), gelatin, dextran and albumin are useful for maintaining renal perfusion and function. The comparative renal effects of colloids have not been previously reviewed. Methods: Computer searches of the MEDLINE and EMBASE bibliographic databases and the Cochrane Library were conducted using the search terms: colloids; hetastarch; gelatin; dextrans; serum albumin; kidney failure; cardiac surgical procedures; and kidney transplantation. Relevant studies were also sought through hand searching and examination of reference lists. Results of identified studies were qualitatively summarized with account taken for potential confounding factors. Results: The three artificial colloids HES, gelatin and dextran all exhibited troublesome renal side-effects. Randomized trials have demonstrated adverse renal effects of HES in sepsis and surgery. Undesirable renal effects are common to all available HES solutions regardless of molecular weight, substitution or C2/C6 ratio. While some of its effects may be less severe than those of HES, gelatin also can adversely affect the kidney. A negative renal impact of dextran is well-established, although this colloid is now less extensively used than formerly. As the normal endogenous colloid, albumin exhibits a wide margin of renal safety, although albumin overdose needs to be avoided. Albumin also appears to exert protective effects on the kidney such as inhibition of apoptosis and scavenging of reactive oxygen species. Conclusions: Colloids display important differences in their actions on the kidney. These contrasting renal effects should be considered in making fluid management decisions.

A small decrease in cerebral blood flow (approximately 10%) in response to 100% oxygen (O2) administration is well recognized. This observation was based on human volunteer studies, which employed a nitrous oxide washout method for the measurement of cerebral blood flow. Because this method is now appreciated to be subject to potential errors we have examined the cerebral blood flow response to 100% oxygen using a magnetic resonance imaging technique to quantify changes in carotid and basilar artery flow. The study, was performed in 12 normal male subjects aged 23–42 years. We report decreases in cerebral blood flow ranging from 9 to 31% with a mean value of over 20%. The decrease in cerebral blood flow was greater in seven young subjects (aged 23–26 years) with decreases in cerebral blood flow of 19.3–31.4% (mean 26.8%). In five older subjects (aged 32–42 years), decreases in CBF were smaller (mean 16.2%). The administration of 100% O2 was accompanied by a small decrease in end-tidal CO2 (3.7–7.1%), insufficient to explain the changes in cerebral blood flow. We conclude that the decrease in cerebral blood flow in response to O2 administration is greater than previously described and appears to be greater in young adults.

Background and objective: The epidural and subarachnoid spaces should be identified at the first attempt, since multiple punctures increase the risk of postdural puncture headache, epidural haematoma and neural trauma. The study aimed to describe the predictors of successful neuraxial blocks at the first attempt.

Methods: After institutional Review Board approval, 1481 patients undergoing spinal or epidural anaesthesia were prospectively enrolled. For each block we recorded: gender, age, height, weight, body habitus, anatomical landmarks (palpability of the spinous processes), spinal anatomy, patient positioning, premedication, needle type and gauge, approach, spinal level of the block, and the provider’s level of experience. Retrieval of cerebrospinal fluid or loss of resistance to saline or air identified the subarachnoid and epidural spaces, respectively. The outcome variable was the first attempt success or failure (whether or not the needle was correctly located with one skin puncture and produced adequate surgical anaesthesia). Backward stepwise logistic regression tested its association with the other variables.

Results: The first-attempt rate of success was 61.51%. Independent predictors (Odds ratio, 95% confidence limits) were the quality of anatomical landmarks (1.92 (1.57; 2.35)), the provider’s level of experience (1.24 (1.15; 1.33)) and the adequacy of patient positioning (3.84 (2.84; 5.19)).

Conclusions: The successful location of the subarachnoid or the epidural space at the first attempt is influenced by the quality of patients’ anatomical landmarks, the adequacy of patient positioning and the provider’s level of experience.

The prediction of difficult intubation in obese patients was investigated by co-estimating the degree of visbility of oropharyngeal structures in conjunction with the respective body mass index. Data were collected prospectively in a series of 1833 consecutive adult patients. Body mass index (BMI) in kg m−2 was used as a measure of obesity (morbid: >40, moderate: 30–40, no obesity: <30). The oropharyngeal class findings were assessed using the original methodology as well as by a modification requiring the tongue to be pulled forward by the examiner. Difficult intubation was defined as inadequate exposure of the glottis by direct laryngoscopy. Both oropharyngeal class methodologies were of equal sensitivity, whereas the modified technique presented a significantly higher positive predictive value (50.0% vs. 37.2%, P<0.01). Statistical analysis revealed an increased risk of dificult laryngoscopy among obese patients compared with subjects with normal body mass index (20.2% vs. 7.6%, P<0.001). When obesity is estimated with respect to oropharyngeal class the positive predictive value is greately improved (66.7% vs. 20.2%, P<0.001). We conclude that obesity which is associated with a disproportionately large base of the tongue, is a predisposing factor for difficult laryngoscopy.

Summary

Background and objectives: Postoperative confusion and delirium is a common complication in the elderly with a poorly understood pathophysiology. The aim of this study was to examine whether the type of anaesthesia (general or regional) plays a role in the development of cognitive impairment in elderly patients during the immediate postoperative period. Methods: Forty-seven patients >60 yr of age and undergoing major surgery were randomly allocated to receive either regional or general anaesthesia. The mental status of the patients was assessed preoperatively and during the first three postoperative days with the Mini Mental State Examination. The incidence of delirium was also examined during the same period with the use of DSM III criteria. Results: Overall, during the first three postoperative days, the mean Mini Mental State Examination score decreased significantly (P < 0.001). However, this decline was very significant only in patients assigned to receive general anaesthesia (P < 0.001) compared to regional anaesthesia. Nine patients developed delirium but the type of anaesthesia did not affect its incidence. The only important factor for the development of delirium was pre-existing cardiovascular disease irrespective of anaesthesia type (P < 0.025). Conclusions: Elderly patients subjected to general anaesthesia displayed more frequent cognitive impairment during the immediate postoperative period in comparison to those who received a regional technique.

Transcranial Doppler is an innovative, flexible, accessible tool for the bedside monitoring of static and dynamic cerebral flow and treatment response. Introduced by Rune Aaslid in 1982, it has become indispensable in clinical practice. The main obstacle to ultrasound penetration of the skull is bone. Low frequencies, 1–2 MHz, reduce the attenuation of the ultrasound wave caused by bone. Transcranial Doppler also provides the advantage of acoustic windows representing specific points of the skull where the bone is thin enough to allow ultrasounds to penetrate. There are four acoustic windows: transtemporal, transorbital, suboccipital and retromandibular. The identification of each intracranial vessel is based on the following elements: (a) velocity and direction; (b) depth of signal capture; (c) possibility of following the vessel its whole length; (d) spatial relationship with other vessels; and (e) response to homolateral and contralateral carotid compression. The main fields of clinical application of transcranial Doppler are assessment of vasospasm, detection of stenosis of the intracranial arteries, evaluation of cerebrovascular autoregulation, non-invasive estimation of intracranial pressure, measure of effective downstream pressure and assessment of brain death. Mean flow velocity is directly proportional to flow and inversely proportional to the section of the vessel. Any circumstance that leads to a variation of one of these factors can thus affect mean velocity. The main pathological condition affecting flow velocity is the vasospasm. Vasospasm is a frequent complication of subarachnoid haemorrhage, it often remains clinically silent and the factors that make it symptomatic are largely unknown. Threshold velocities above which vasospasm comes into place are well defined as regards the median cerebral artery, while there is no consensus for the other vessels. Nevertheless, an increase in velocity alone is not sufficient to arrive at a diagnosis of vasospasm; a condition of hyperaemia also presents with an increase in flow velocity. The Lindegaard Index has therefore been introduced, which is defined by the ratio between the mean flow velocity in the median cerebral artery and the mean flow velocity in the internal carotid artery. Criteria for diagnosis of a stenosis >50% of an intracranial vessel with transcranial Doppler include: (a) segmentary acceleration of flow velocity; (b) drop in velocity below the stenotic segment; (c) asymmetry; and (d) circumscribed flow disturbances (turbulence and musical murmur). The transcranial Doppler enables us to assess both components of self-regulation. The static component is measured by observing changes in flow velocity caused by pharmacologically induced episodes of hypertension and hypotension. The dynamic component of autoregulation can be measured using a method devised by Aaslid known as the ‘cuff test’. A very effective and safe device for measuring cerebral autoregulation is the transient hyperaemic response test. This test is based on the compensatory vasodilatation of the arterioles, which occurs after brief compression of the common carotid. Csonyka proposed the following formula based on clinical observation for the calculation of cerebral perfusion pressure: CPP = MAP × FVd/FVm + 14. Brain death is defined as the irreversible cessation of all functions of the whole brain. The clinical criteria are usually considered sufficient to establish a diagnosis of brain death; however, they might not be sufficient in patients who have been on sedatives or when there are ethical or legal controversies. Many authors have demonstrated the existence of a transcranial Doppler pattern, which is typical of brain death.