Showing papers in "BJA: British Journal of Anaesthesia in 1997"

Multimodal approach to control postoperative pathophysiology and rehabilitation.

Abstract: Major surgery is still associated with undesirable sequelae such as pain, cardiopulmonary, infective and thromboembolic complications, cerebral dysfunction, nausea and gastrointestinal paralysis, fatigue and prolonged convalescence. The key pathogenic factor in postoperative morbidity, excluding failures of surgical and anaesthetic technique, is the surgical stress response with subsequent increased demands on organ function. These changes in organ function are thought to be mediated by trauma-induced endocrine metabolic changes and activation of several biological cascade systems (cytokines, complement, arachidonic acid metabolites, nitric oxide, free oxygen radicals, etc). To understand postoperative morbidity it is therefore necessary to understand the pathophysiological role of the various components of the surgical stress response and to determine if modification of such responses may improve surgical outcome. While no single technique or drug regimen has been shown to eliminate postoperative morbidity and mortality, multimodal interventions may lead to a major reduction in the undesirable sequelae of surgical injury with improved recovery and reduction in postoperative morbidity and overall costs.

Central nervous and cardiovascular effects of i.v. infusions of ropivacaine, bupivacaine and placebo in volunteers.

Abstract: We have compared the incidence of CNS symptoms and changes in echocardiography and electrophysiology during i.v. infusions of ropivacaine, bupivacaine and placebo. Acute tolerance of i.v. infusion of 10 mg min-1 was studied in a crossover, randomized, double-blind study in 12 volunteers previously acquainted with the CNS effects of lignocaine. The maximum tolerated dose for CNS symptoms was higher after ropivacaine in nine of 12 subjects and higher after bupivacaine in three subjects. The 95% confidence limits for the difference in mean dose between ropivacaine and bupivacaine were -30 and 7 mg. The maximum tolerated unbound arterial plasma concentration was twice as high after ropivacaine (P

The intubating laryngeal mask. II: A preliminary clinical report of a new means of intubating the trachea.

Abstract: We have assessed the efficacy of a new laryngeal mask prototype, the intubating laryngeal mask airway (ILMA), as a ventilatory device and blind intubation guide. The ILMA consists of an anatomically curved, short, wide bore, stainless steel tube sheathed in silicone which is bonded to a laryngeal mask and a guiding handle. It has a single moveable aperture bar, a guiding ramp and can accommodate an 8 mm tracheal tube (TT). After induction of anaesthesia with propofol 2.5 mg kg-1 and fentanyl 2.5 micrograms kg-1, the device was inserted successfully at the first attempt in all 150 (100%) patients and adequate ventilation achieved in all, with minor adjustments required in four patients. Placement did not require movement of the head and neck or insertion of the fingers in the patient's mouth. Blind tracheal intubation using a straight silicone cuffed TT was attempted after administration of atracurium 0.5 mg kg-1. If resistance was felt during intubation, a sequence of adjusting manoeuvres was used based on the depth at which resistance occurred. Tracheal intubation was possible in 149 of 150 (99.3%) patients. In 75 (50%) patients no resistance was encountered and the trachea was intubated at the first attempt, 28 (19%) patients required one adjusting manoeuvre and 46 (31%) patients required 2-4 adjusting manoeuvres before intubation was successful. There were 13 patients with potential or known airway problems. The lungs of all of these patients were ventilated easily and the trachea intubated using the ILMA. In 10 of 13 (77%) of these patients, no resistance was encountered and the trachea was intubated at the first attempt; three of 13 (23%) patients required one adjusting manoeuvre. Tracheal intubation required significantly fewer adjusting manoeuvres in patients with a predicted or known difficult airway (P

Propofol anaesthesia and postoperative nausea and vomiting: quantitative systematic review of randomized controlled studies.

Abstract: We have analysed randomized controlled studies which reported the incidence of postoperative nausea and vomiting (PONV) after propofol anaesthesia compared with other anaesthetics (control). Cumulative data of early (0-6 h) and late (0-48 h) PONV were recorded as occurrence or non-occurrence of nausea or vomiting. Combined odds ratio and number-needed-to-treat were calculated for propofol as an induction or maintenance regimen, early or late outcomes, and different emetic events. This was performed for all control event rates and within a range of 20-60% control event rates. We analysed 84 studies involving 6069 patients. The effect of propofol on PONV was dependent mainly on the method of administration, time of measurement and range of control event rates. When all studies were included the number-needed-to-treat to prevent PONV with propofol was more than 9 when used for induction of anaesthesia and at best 6 when used for maintenance. Within the 20-60% control event rate range, best results were achieved with propofol maintenance to prevent early PONV: the number-needed-to-treat to prevent early nausea was 4.7 (95% confidence interval 3.8-6.3), vomiting 4.9 (4-6.1) and any emetic event 4.9 (3.7-7.1). Within the 20-60% control event rate, of five patients treated with propofol for maintenance of anaesthesia, one will not vomit or be nauseated in the immediate postoperative period who would otherwise have vomited or been nauseated. This may be clinically relevant. In all other situations the difference between propofol and control may have reached statistical significance but was of doubtful clinical relevance. Treatment efficacy should be established within a defined range of control event rates for meaningful estimates of efficacy and for comparisons.

The intubating laryngeal mask. I: Development of a new device for intubation of the trachea.

Abstract: The standard laryngeal mask airway (LMA) functions both as a ventilatory device and as an aid to blind/fibrescopic-guided tracheal intubation. We describe the radiological and laboratory work used to bioengineer a new laryngeal mask prototype, the intubating laryngeal mask airway (ILMA). The aim was to create a new airway system with better intubation characteristics than the LMA. Other design goals were to eliminate the need for head-neck manipulation and insertion of fingers in the mouth during placement. Development was aided by analysis of magnetic resonance images of the human pharynx and laboratory testing with a variety of tracheal tubes. The principal features of this new system are an anatomically curved, rigid airway tube with an integral guiding handle, an epiglottic elevating bar replacing the mask bars, a guiding ramp built into the floor of the mask aperture and a modified silicone tracheal tube developed for use with the device.

Relationship between calculated blood concentration of propofol and electrophysiological variables during emergence from anaesthesia: comparison of bispectral index, spectral edge frequency, median frequency and auditory evoked potential index.

Abstract: We studied four electrophysiological variables (bispectral index (BIS), 95% spectral edge frequency (SEF), median frequency (MF) and auditory evoked potential index (AEP index) in 10 patients during emergence from anaesthesia. We compared correlation of the signals with gradually decreasing calculated blood propofol concentrations, and evaluated the signal differences between preinduction and emergence from anaesthesia. Values of BIS, MF and SEF correlated with calculated blood concentrations of propofol during emergence from anaesthesia. The correlation was best with BIS, but was poor with MF and SEF at low calculated blood propofol concentrations. Although AEP index values did not correlate with calculated blood concentrations of propofol during emergence from anaesthesia, values after eye opening and before anaesthesia were well distinguished from those during emergence from anaesthesia. BIS correlated best with calculated blood concentrations of propofol. AEP index appeared to distinguish the awake from asleep state.

Inhalation induction with sevoflurane: a double-blind comparison with propofol.

Abstract: We conducted a randomized, double-blind comparison of 8% sevoflurane and propofol as induction agents for day-case cystoscopy in 102 patients. All patients received an i.v. cannula and breathed oxygen 5 litre min-1. Anaesthesia was induced with propofol i.v. or inhalation of 8% sevoflurane and 10% Intralipid (as a placebo) i.v., delivered by a blinded observer. Anaesthesia was maintained in all patients with 2% sevoflurane via a face mask. Induction of anaesthesia with sevoflurane was significantly slower compared with propofol (mean 84 (SD 24) s vs 57 (11) s), but was associated with a lower incidence of apnoea (16% vs 65%) and a shorter time to establish spontaneous ventilation (94 (34) s vs 126 (79) s). Induction complications were uncommon in each group but the transition to maintenance was smoother with sevoflurane and was associated with less hypotension compared with propofol. Emergence from anaesthesia induced with sevoflurane occurred significantly earlier compared with propofol (5.2 (2.2) min vs 7.0 (3.2) min) and anaesthetic induction was also significantly cheaper with sevoflurane. According to a postoperative questionnaire, the majority of patients found both anaesthetic techniques acceptable. Nevertheless, significnatly more patients (14%) rated induction with sevoflurane as unpleasant compared with propofol (0) and significantly more patients (24%) would not choose sevoflurane induction compared with propofol (6%). This phenomenon may have been related to the particular patient population studied, however. Inhalation induction with 8% sevoflurane would appear to offer several objective advantages compared with induction with propofol in day-case patients, although a significant minority may dislike this technique.

Cytokines in anaesthesia.

Abstract: The scope of cytokine biology is fascinating with widespread applications anticipated in many areas of medical science. We have emphasized the fundamental roles that cytokines play in the control of normal immunological functions, defence mechanisms and normal cell growth, and how major surgery and trauma can affect these processes. It remains to be determined if morbidity and mortality may be improved after major illness and surgery by altering cytokine production and function.

Propofol and bradycardia: causation, frequency and severity.

Abstract: As part of the development of a model for the study of adverse events, we have investigated the risk of bradycardia with propofol. A systematic search for any type of report, published and unpublished, was made to review the evidence that propofol increases the risk of bradycardia, asystole and death from bradycardic events. Quantitative and qualitative analyses of data with different strengths of evidence were performed. Sixty-five published and 187 spontaneous reports to drug monitoring centres described with different strength of evidence a biological basis for propofol-induced bradycardia, 1444 bradycardias, 86 asystoles and 24 deaths. In controlled clinical trials, propofol significantly increased the risk of bradycardia compared with other anaesthetics (number-needed-to-harm 11.3 (95% confidence interval 7.7-21)). In paediatric strabismus surgery the number-needed-to-harm was 4.1 (3-6.7). One of 660 patients undergoing propofol anaesthesia had an asystole. The risk of bradycardia-related death during propofol anaesthesia was estimated to be 1.4 in 100,000. Data from the phase IV study of propofol did not agree with data from controlled studies. Propofol carries a finite risk for brady-cardia with potential for major harm. Study of adverse events should be made with systematically searched data and, in contrast with study of efficacy, not restricted to randomized, controlled trials.

Phantom pain and sensation among British veteran amputees.

Abstract: Using a mail-delivered questionnaire, we surveyed 590 veteran amputees concerning phantom pain, phantom sensation and stump pain. They were selected randomly from a population of 2974 veterans with long-standing limb amputation(s) using a computer random number generator. Eighty-nine percent responded and of these, 55% reported phantom limb pain and 56% stump pain. There was a strong correlation between phantom pain and phantom sensation. The intensity of phantom sensation was a significant predictor for the time course of phantom pain. In only 3% of phantom limb pain sufferers did the condition become worse. One hundred and forty-nine amputees reporting phantom pain discussed their pain with their family doctors; 49 were told that there was no treatment available. Transcutaneous electric nerve stimulation, analgesics and non-steroidal anti-inflammatory drugs were satisfactory methods for controlling phantom limb pain.

Comparison of volume controlled with pressure controlled ventilation during one-lung anaesthesia

Abstract: Pressure controlled ventilation (PCV) is an alternative mode of ventilation which is used widely in severe respiratory failure. In this study, PCV was used for one-lung anaesthesia and its effects on airway pressures, arterial oxygenation and haemodynamic state were compared with volume controlled ventilation (VCV). We studied 48 patients undergoing thoracotomy. After two-lung ventilation with VCV, patients were allocated randomly to one of two groups. In the first group (n = 24), one-lung ventilation was started by VCV and the ventilation mode was then switched to PCV. Ventilation modes were performed in the opposite order in the second group (n = 24). We observed that peak airway pressure (P = 0.000001), plateau pressure (P = 0.01) and pulmonary shunt (P = 0.03) were significantly higher during VCV, whereas arterial oxygen tension (P = 0.02) was significantly higher during PCV. Peak airway pressure (Paw) decreased consistently during PCV in every patient and the percentage reduction in Paw was 4-35% (mean 16.1 (SD 8.4) %). Arterial oxygen tension increased in 31 patients using PCV and the improvement in arterial oxygenation during PCV correlated inversely with preoperative respiratory function tests. We conclude that PCV appeared to be an alternative to VCV in patients requiring one-lung anaesthesia and may be superior to VCV in patients with respiratory disease.

The intubating laryngeal mask airway: an initial assessment of performance.

Abstract: A new prototype of the laryngeal mask airway (LMA), the intubating laryngeal mask airway (ILMA), was used to facilitate tracheal intubation in 100 fasted patients presenting for elective surgery. Alignment of the ILMA with the larynx was assessed fibreoptically before intubation without the investigator performing the intubation being aware of the view score. Ease of intubation correlated with the view obtained and with the degree of manipulation of the ILMA needed to achieve tracheal intubation. Intubation was successful in 93 patients. Of the seven intubation failures, five occurred in the first 20 patients. Conventional connection to the breathing system and ventilation of the lungs of the patients were possible throughout the intubation procedure.

Effect of progressive haemodilution with hydroxyethyl starch, gelatin and albumin on blood coagulation.

Abstract: We have compared the effects of progressive (30% and 60%) in vitro haemodilution with hydroxyethyl starch (HES), gelatin (GEL) and albumin (ALB) with haemodilution using 0.9% saline in 96 patients by thrombelastography. Haemodilution with HES, GEL and ALB significantly (P

Actions of tramadol, its enantiomers and principal metabolite, O-desmethyltramadol, on serotonin (5-HT) efflux and uptake in the rat dorsal raphe nucleus

Abstract: Tramadol is an atypical centrally acting analgesic agent with relatively weak opioid receptor affinity in comparison with its antinociceptive efficacy. Evidence suggests that block of monoamine uptake may contribute to its analgesic actions. Therefore, we have examined the actions of (+/-)-tramadol, (+)-tramadol, (-)-tramadol and O-desmethyltramadol (M1 metabolite) on electrically evoked 5-HT efflux and uptake in the dorsal raphe nucleus (DRN) brain slice, measured by fast cyclic voltammetry. Racemic tramadol and its (+)-enantiomer (both 5 mumol litre-1) significantly blocked DRN 5-HT uptake (both P

Meta-analytic comparison of prophylactic antiemetic efficacy for postoperative nausea and vomiting: propofol anaesthesia vs omitting nitrous oxide vs total i.v. anaesthesia with propofol.

Abstract: Data from two published and one new meta-analysis were reviewed to compare the antiemetic efficacy of three different anaesthetic regimens: (i) propofol anaesthesia compared with another anaesthetic (control); (ii) anaesthesia without nitrous oxide compared with the same anaesthetic with nitrous oxide (control); (iii) propofol anaesthesia without nitrous oxide (TIVA) compared with another anaesthetic with nitrous oxide (control). Efficacy (prevention of postoperative nausea and vomiting compared with control) was estimated using odds ratio and number-needed-to-treat methods, and compared within a range of 20-60% control event rates for early efficacy (0-6 h) and 40-80% for late efficacy (0-48 h). Propofol anaesthesia or omitting nitrous oxide had similar effects on vomiting, both early and late. Propofol (but not omitting nitrous oxide) decreased the incidence of nausea. TIVA studies were documented poorly; appropriate comparison with other interventions were not possible. Efficacy of treatments should be compared within a setting-specific range of control event rates. There is insufficient evidence that TIVA with propofol is an anaesthetic technique with a low emetogenic potency.

Transcranial cytokine gradients in patients requiring intensive care after acute brain injury.

Abstract: After acute brain injury there may be increased intracranial production of cytokines, with activation of inflammatory cascades. We have sought to determine if a transcranial cytokine gradient was demonstrable in paired sera of 32 patients requiring intensive care after acute brain injury. The difference between concentrations of IL-1 beta, IL-6, IL-8 and TNF alpha in jugular venous and arterial serum was measured on admission, and at 24, 48 and 96 h after the primary injury. There were no differences in IL-1 beta, IL-8 or TNF alpha, but median gradients of 6.7 and 11.5 pg ml-1 for IL-6 were demonstrated in the traumatic brain injury (n = 22) and subarachnoid haemorrhage (n = 10) groups, respectively (normal values in serum

Effect of clonidine and dexmedetomidine premedication on perioperative oxygen consumption and haemodynamic state.

Abstract: Premedication has been shown to affect both oxygen consumption and metabolic rate. We have compared the perioperative metabolic and haemodynamic effects of two alpha 2-agonists, clonidine and the more selective dexmedetomidine, in 30 ASA I patients undergoing plastic surgical procedures under general anaesthesia. Patients were premedicated with clonidine 4 micrograms kg-1 (n = 10), dexmedetomidine 2.5 micrograms kg-1 (n = 10) or saline (n = 10) i.m. The doses of clonidine and dexmedetomidine were intended to be equipotent. The maximum decrease in preoperative oxygen consumption was 8% and decreases in systolic and diastolic arterial pressures were 11% from baseline after clonidine and dexmedetomidine. During operation, the maximum reduction in heart rate was 18% in the clonidine and dexmedetomidine groups compared with the placebo group. After operation, the maximum decrease in systolic arterial pressure was 11%, diastolic arterial pressure 15% and oxygen consumption 17% in the clonidine and dexmedetomidine groups compared with placebo. In summary, both clonidine 4 micrograms kg-1 and dexmedetomidine 2.5 micrograms kg-1 decreased perioperative oxygen consumption effectively, with a similar haemodynamic profile.

Spontaneous movements associated with rocuronium: is pain on injection the cause?

Abstract: Spontaneous movements are sometimes observed of the arm into which rocuronium is administered. In order to assess a possible relationship between these movements and pain, we injected in 10 awake, ASA I patients, in a double-blind manner, both rocuronium 1 ml (10 mg) and 0.9% NaCI 1 ml (placebo), with a 30-s interval in between. None of the patients receiving placebo complained of pain, but eight of 10 patients reported a strong burning pain during injection of rocuronium with brisk flexion of the elbow and wrist, similar to those observed in patients after induction of anaesthesia. A second injection of rocuronium did not produce such pain and no movements were observed. We conclude that injection of rocuronium is associated with severe, burning pain of short duration, responsible for the spontaneous movements in the arm observed after induction of anaesthesia.

Effects on haemodynamics and catecholamine release of xenon anaesthesia compared with total i.v. anaesthesia in the pig.

Abstract: In order to investigate haemodynamic response and catecholamine release during anaesthesia with xenon, we conducted a study on 28 pigs which were allocated randomly to one of four groups: total i.v. anaesthesia with pentobarbitone and buprenorphine, and xenon anaesthesia with inspiratory concentrations of 30%, 50% or 70%, respectively, supplemented with pentobarbitone. Haemodynamic variables were measured using arterial and Swan Ganz catheters. Depth of anaesthesia was monitored using spectral edge frequency analysis. Plasma concentrations of dopamine, noradrenaline and adrenaline were measured by high pressure liquid chromatography. All haemodynamic variables and plasma concentrations of dopamine and noradrenaline remained within normal limits. Adrenaline concentrations were reduced significantly in all groups. Xenon anaesthesia was associated with a high degree of cardiovascular stability. Significant reduction in adrenaline concentrations at inspiratory xenon concentrations of 30% and 50% can be explained by analgesic effects of xenon below its MAC value.

Immersion, near-drowning and drowning

Abstract: or death. However, pulmonary complications may follow aspiration of water without cessation of breathing or loss of consciousness. Thus “near-drowning” should be defined as “survival, at least temporarily, after aspiration of fluid into the lungs”. The importance of the distinction between the two definitions is that aspiration of fluid may lead to later pulmonary complications, even in those

Effect of systemic N-methyl-D-aspartate receptor antagonist (dextromethorphan) on primary and secondary hyperalgesia in humans.

Abstract: Dextromethorphan is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist known to inhibit wind-up and central hyperexcitability of dorsal horn neurones. We studied 24 healthy, unmedicated male volunteers, aged 21-28 yr, in a randomized, double-blind, placebo-controlled, crossover study. Burn injuries were produced on the medial surface of the dominant calf with a 25 x 50 mm rectangular thermode. On three separate days, at least 1 week apart, subjects were given oral dextromethorphan 60 mg, 120 mg or placebo. Dextromethorphan reduced the magnitude of secondary hyperalgesia to pinprick but not to stroke. Dextromethorphan had no influence on primary hyperalgesia, pain during prolonged noxious heat stimulation or heat pain detection thresholds in undamaged skin. Side effects were frequent but clinically acceptable. The effects of dextromethorphan were in agreement with experimental studies indicating that dextromethorphan is a NMDA receptor antagonist. The effects of dextromethorphan in the burn injury model were similar to those of ketamine and distinct from those of local anaesthetics and opioids.

Glutamate: a role in normal brain function, anaesthesia, analgesia and CNS injury

Abstract: Glutamate is the major excitatory amino acid (EAA) neurotransmitter in the central nervous system (CNS). 78 EAA neurones and synapses are distributed widely throughout the CNS, 36 231 but they are concentrated particularly in the hippocampus, 91 the outer layer s of the cer ebr alor tex 91 and the substantia gelatinosa of the spinal cord. 194 Within these regions EAA play key roles in physiological processes including learning and memory (and hence awareness under anaesthesia), central pain transduction mechanisms and pathological processes such as excitotoxic neuronal injury which follows CNS trauma or ischaemia. Thus an understanding of the role of EAA in the CNS is relevant to normal higher brain function and to anaesthesia, analgesia and intensive care. A broad spectrum of pharmacological agents which alter EAA-mediated neurotransmission are already available and many more are under development. These include: (i) drugs that specifically target the re leasef EAA (e.g. theovel antiepileptic drugs felbamate and lamotrigine), (ii) drugs that modify the inter actions of EAA with specific re ceptors (e.g ketamine) and (iii) volatile and i.v. anaesthetic agents which may have a common mechanism of action that, at least in part, involves EAAmediated neurotransmission. To understand the potential applications of these agents it is necessary to consider fir stow EAA actt the levelf the synapse and the individual neurone. To do so involves a brief outline of EAA receptor subtypes and how their activation affects the postsynaptic neurone. It may then be possible to explain how EAA and their receptors are involved in cognition, anaesthesia, analgesia and neurointensive care and therefore to provide a framework to assess the possible clinical applications of drugs which modify EAA-mediated neurotransmission.

Comparison of the accuracy of the lithium dilution technique with the thermodilution technique for measurement of cardiac output.

Abstract: A new indicator dilution technique for measurement of cardiac output is described. Lithium chloride is injected via a central venous catheter and its dilution curve measured in arterial blood using a lithium-selective electrode. We assessed the lithium dilution cardiac output measurement (LiDCO) and a conventional thermodilution cardiac output measurement (ThDCO) by comparing the results of both with cardiac output determined by electromagnetic flowmetry (EMCO) under controlled laboratory conditions in 10 swine. They were monitored with a pulmonary artery catheter, femoral artery catheter and electromagnetic flowmeter placed around the ascending aorta. LiDCO, ThDCO and EMCO measurements were determined at baseline, in a hyperdynamic state produced by administration of dobutamine, at a second baseline and finally in a hypodynamic state induced by propranolol during deep anaesthesia. Data were analysed by linear regression analysis and the comparison method described by Bland and Altman; bias and precision of both LiDCO and ThDCO compared with EMCO were calculated by the method of Sheiner and Beal. The correlation coefficient between LiDCO and EMCO (0.95) was higher than that between ThDCO and EMCO (0.87). The precision value of LiDCO (0.04) was significantly less (i.e. better) than that of ThDCO (0.09). The results of this study indicated that LiDCO was more reliable compared with conventional ThDCO.

Leakage of fluid past the tracheal tube cuff in a benchtop model.

Abstract: We have assessed a range of high volume, low pressure (HVLP) cuffed tracheal tubes in a benchtop model, for leakage of fluid from above the cuff to the model trachea below, during various ventilatory modes. Rapid leakage occurred in the model during all modes of ventilation, unless tracheal pressure was greater than the height of fluid in the column above the cuff. This leakage occurred preferentially down longitudinal folds that occur in the HVLP cuff wall. This model suggests that, if a longitudinal fold within the cuff wall is patent, then the possibility exists of subglottic to tracheal leakage.

Extradural pain relief in labour: bupivacaine sparing by extradural fentanyl is dose dependent.

Abstract: The minimum local analgesic concentration (MLAC) of bupivacaine in labour is defined as the effective concentration in 50% of subjects (EC50). We have used the technique of double-blinded sequential allocation to quantify the bupivacaine sparing effect of the addition of four different doses of extradural fentanyl in 223 labouring women. There were five groups: (1) plain bupivacaine (control); (2) bupivacaine with fentanyl 1 microgram ml-1; (3) bupivacaine with fentanyl 2 micrograms ml-1; (4) bupivacaine with fentanyl 3 micrograms ml-1; and (5) bupivacaine with fentanyl 4 micrograms ml-1. The MLAC of bupivacaine were 0.069% w/v, 0.057% w/v, 0.048% w/v, 0.031% w/v and 0.015% w/v, respectively. We observed a reduction in MLAC of 18%, 31% (P = 0.03%), 55% (P

Perioperative myocardial cell injury: the role of troponins.

Abstract: Early recognition of minor myocardial cell injury and appropriate treatment may prevent development of myocardial infarction as one of the most severe postoperative cardiac complications. Troponins have been shown to be sensitive biochemical markers for the assessment of myocardial cell injury. We investigated prospectively 67 cardiac risk patients undergoing elective non-cardiac surgery. Troponin T (TNT) concentrations were measured during the perioperative period, and in those patients with increased TNT (cut-off 0.2 ng ml-1), troponin I (TNI) concentrations were measured additionally (cut-off 0.6 ng ml-1). Patients were allocated to one of three groups: group I, all patients with normal TNT concentrations had a good cardiac outcome (80.5%). In those patients with increased TNT concentrations (19.5%) TNI was also positive; group II, patients (8.8%) with only slightly increased TNT concentrations (0.32-0.99 ng ml-1) also had a good outcome, indicating minor myocardial cell injury, whereas patients with cardiac complications (11.9%) had higher TNT concentrations (0.47-9.8 ng ml-1) (P

Role of vasopressin in the haemodynamic response to laparoscopic cholecystectomy.

Abstract: We studied 10 patients undergoing laparoscopic cholecystectomy (group 1) and five control patients (group 2). We measured heart rate, arterial pressure, right atrial pressure (RAP), cardiac index (CI), systemic vascular resistance index (SVRI), intrathoracic pressure (ITP), plasma osmolality, adrenaline, noradrenaline and arginine vasopressin (aVP) concentrations, and serum renin activity (SRA), and calculated the atrial transmural pressure gradient (ATPG). We recorded significant decreases in mean arterial pressure (MAP), SVRI and CI in both groups (P

Mechanism of femoral nerve palsy complicating percutaneous ilioinguinal field block.

Abstract: Femoral nerve palsy has been reported after percutaneous ilioinguinal field infiltration with general anaesthesia for inguinal herniorrhaphy. The mechanism whereby this could occur was studied in cadaver dissections. It was found that the plane between the transversus abdominis muscle and the transversalis fascia was continuous laterally with the tissue plane deep to the iliacus fascia, which is the plane containing the femoral nerve. Injection of methylene blue 1 ml into this plane resulted in pooling of dye around the femoral nerve. Femoral nerve palsy may result from infiltration of a sufficient volume of local anaesthetic into the plane between the transversus abdominis muscle and the transversalis fascia with tracking of the injectate deep to the iliacus fascia to affect the femoral nerve. This finding has important implications for the performance of a percutaneous ilioinguinal field block particularly in day surgery provision.