Showing papers in "Acta Anaesthesiologica Scandinavica in 1996"

Good Clinical Research Practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents

Abstract: Based on an international consensus conference held in Copenhagen in the autumn of 1994, a set of guidelines for Good Clinical Research Practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents are presented. The guidelines are intended to be a help for people working in this research field, and it is hoped that the guidelines will assist researchers, editors, and drug companies to enhance the quality of their pharmacodynamic studies of neuromuscular blocking agents.

Treatment of acute reflex sympathetic dystrophy with DMSO 50% in a fatty cream

Abstract: Acute Reflex Sympathetic Dystrophy (acute RSD) was defined using a reproducible classification. Elevated temperature of the affected extremity ("calor"), measured by the dorsal side of the observer's hand and mentioned by the patient, pain ("dolor") measured by the Visual Analogue Scale (VAS), redness ("rubor"), edema ("tumor") and limited active range of motion ("functio laesa"), all contributed to the classification system. Patients scoring 4 to 5 positive symptoms were considered to have acute RSD. A prospective, randomized and double blind study was performed in 32 patients, all suffering from acute RSD. In all of these patients the primary injury was the result of a previous accident. One patient was taken out of the study because of his surgery. The study involved treatment with a fatty cream with 50% dimethyl sulfoxide (DMSO, group A), or without DMSO (placebo, group B), both for 2 months. All patients received physiotherapy applied within pain limits. Application of the creams resulted in both groups in an improvement of RSD-scores and VAS-scores after 2 months. However, the improvement of the RSD score in patients of group A (DMSO-group) was significantly (P < 0.01) better compared to group B. The results suggest a certain activity of DMSO 50% cream in patients suffering from RSD and is, therefore, recommendable.

Intensive care unit stay is prolonged in chronic alcoholic men following tumor resection of the upper digestive tract

Abstract: Background: The prevalence of chronic alcohol misuse in patients with oral, pharyngeal, laryngeal or esophageal carcinomas exceeds 60%. No data is available, to our knowledge, on the morbidity and mortality of chronic alcoholics in surgical intensive care units (ICU) following tumor resection. We investigated whether the subsequent ICU stay in chronic alcoholics following tumor resection was prolonged and whether the incidence of pneumonia and sepsis was increased. Methods: 213 patients with carcinomas of the upper digestive tract were evaluated regarding their drinking habits. Chronic alcoholics met either the DSM-III-R criteria for alcohol abuse or dependence. Conventional laboratory markers and serum carbohydrate-deficient transferrin were determined preoperatively. Major intercurrent complications during ICU stay such as an alcohol withdrawal syndrome, pneumonia and sepsis as well as the frequency of death were documented. Results: Patients did not differ significantly between groups regarding age or APACHE score on admission to the ICU. 121 patients were diagnosed as being chronic alcoholics, 39 as being social drinkers and 61 as being non-alcoholics. In chronic alcoholics the frequency of death was significantly increased. Due to the increased incidence of pneumonia and sepsis the ICU stay was significantly prolonged in chronic alcoholics by approximately 8 days. Conclusions: The increased mortality and morbidity rate demonstrates that chronic alcoholics undergoing major tumor surgery have to be considered as high-risk patients during their postoperative ICU stay. Further studies are required with respect to the immuno-competence of chronic alcoholics and the prevention of alcohol withdrawal syndrome, pneumonia and sepsis in these patients.

Prediction of difficult intubation

Abstract: The incidence of a difficult laryngoscopy or intubation varies from 1.5% to 13%, and failed intubation has been identified as one of the anaesthesia-related causes of death or permanent brain damage. Problems in the airway management can be predicted based on previous anaesthesia records, the medical history of the patient and a physical examination. Several radiological measurements have been reported to be associated with a difficult intubation. The sensitivities of the commonly used bedside tests i.e. the Mallampati classification and the thyromental distance have been reported to be from 42% to 81%, and from 62% to 91%, respectively. The figures for the specificity have varied from 66% to 84% and from 25% to 82%, respectively. The other subjective assessments and objective measurements employed for the prediction of a difficult intubation reach comparable sensitivities and specificities. Evidently, the positive predictive value is improved, if combinations of tests are used.

Assessment of anaesthesia depth

Abstract: ity and muscle relaxation (1). Anaesthesia implies that the patient neither perceives nor recalls pain 01 any event that occurred during surgery (2). Appropriate administration of anaesthetics takes into account that various components of anaesthesia are the result of different pharmacological actions, with different underlying mechanisms of action (3). Drugs used in anaesthetic practice have varying potency with respect to these anaesthetic components (3). Depth of anaesthesia depends on two antagonizing factors: the anaesthetic, which induces different anaesthesia components to a varying degree depending on the specific drug used; and the surgical stimulation, which may activate the sympathetic nervous system and increase the patient’s level of.. consciousness and the somatic and autonomic reactivity (4-6). Adequate depth of anaesthesia requires a sufficient amount of the agent to secure unconsciousness and other components of anaesthesia as needed for that particular surgical procedure, without jeopardizing vital organ functions. Ideally, depth of anaesthesia should be assessed in relationship to each anaesthetic component separately, tested by specific stimuli (I, 3). Studies suggest that a consciousness transition zone exists during the induction and emergence from anaesthesia (7-11). At low T” sciousness, analgesia, autonomic reflex stabilbrain concentrations of anaesthetics the patient responds to verbal commands and has explicit (conscious) recall of the event. At higher concentrations the patient may remember the event if offered a Cue (cued conscious recognition). At even higher concentrations the ability for explicit memory is lost, but the patient may still respond to auditory impulses such as verbal commands (wakefulness), or retain information as implicit (unconscious) memory, only revealed by psychologic testing and hypnosis (10, 12-14). It must be a primary goal of anaesthesia to secure an anaesthetic depth that eliminates any memory function during surgery. The drug concentration required to eliminate memory functions in the presence of surgical stimuli is not known, but it is reasonable to believe that it is higher than in unstimulated volunteers, as noxious stimuli may increase the level of consciousness (5,9). Despite a 150-year history of anaesthesia, at present no definite clinical sign exists that can serve as a basis for rational administration of drugs to achieve unconsciousness (1). Therefore, awareness incidents occur, although anaesthesia otherwise may be ,judged clinically adequate (4). However, the freqency of awareness may be reduced by improved clinical observation during anaesthesia (4), or by the introduction of monitoring systems that register the patient‘s level of consciousness.

Cytokines in stored red blood cell concentrates: promoters of systemic inflammation and simulators of acute transfusion reactions?

Abstract: Background: The cytokine network has important implications for the systemic inflammatory and metabolic response in trauma and infection. Cytokines exogenously administered to traumatized and infected patients may have implications for the trauma response in these patients. The main objective of this study was to characterize red blood cell concentrates (RBCs) with regard to cytokine content. Methods: We investigated the concentrations of tumor necrosis factor α (TNF), interleukin-1 β (IL-1), interleukin-6 (IL-6) and interleukin-8 (IL-8) in sixteen units of RBCs stored at +4° C during 40 days. Samples from RBCs were taken every tenth day. Healthy volunteers were used as controls. Results: IL-1 and IL-8 in RBCs were increased compared to controls, P< 0.01 - P < 0.001 and TNF in RBCs were increased on days 1 and 40 compared to controls, P < 0.05. During storage TNF was highest on day 1, 69 (< 3 - 1060) pg/ml, median (range). IL-1 concentrations increased during the period of storage from 5 (< 2 - 205) pg/ml to 174 (< 2 - 2180) pg/ml, P < 0.01. IL-6 was 6 (< 2 - 210) pg/ml on day 1 and did not change over the period of storage. IL-8 was highest on day 40,164 (15 - 790) pg/ml and compared to day 1 the concentrations were increased on day 10 and day 40, P < 0.05 for both comparisons. Conclusions: The results indicate the presence of TNF, IL-1, IL-6 and IL-8 in stored RBCs, though there was a great variability over the period of storage and between units of RBCs. In some samples of RBCs the content of cytokines reached levels that may be anticipated to contribute to systemic inflammation and the symptomatology of acute transfusion reactions.

Routine preoperative gastric emptying is seldom indicated. A study of 85 594 anaesthetics with special focus on aspiration pneumonia

Abstract: Background: The aim of this study was to determine the incidence and severity of pulmonary aspiration of gastric contents during anaesthesia, to determine the short- and long-term morbidity, and to evaluate present routines for preoperative gastric emptying. During the study period, preoperative gastric emptying was done only when intestinal obstruction was suspected. Methods: We routinely record prospectively all problems during and after anaesthesia by means of a database. All data for the 5 years from 1989 to 1993, a total of 85 594 anaesthetic procedures, were analyzed. The hospital charts were also reviewed for those patients where aspiration to the lungs had occurred. Results: Pulmonary aspiration of gastric contents was detected in 25 cases; all occurred in patients receiving general anaesthesia. The incidence was 4.1 times higher in emergency procedures than in electives. There were no aspirations in 30 199 patients receiving regional anaesthesia. The complication occurred in all phases of anaesthesia, but clinical morbidity was low in most cases. Three cases showed serious morbidity immediately after the event, but recovered. Two cases showed serious long-term morbidity, but also recovered completely. No patients died. No cases, except possibly one, might have been prevented by stricter routines for preoperative gastric emptying. Conclusion: We found a low incidence of pulmonary aspiration. When it occurs, it carries a low risk for serious morbidity. Emergency cases for general anaesthesia are most at risk. Regional anaesthesia is considered safe. There is no evidence that preoperative gastric emptying should be routinely done in emergency cases, except in patients with suspected ileus/subileus.

Cerebral autoregulation is impaired in patients resuscitated after cardiac arrest

Abstract: Background: Cerebral autoregulation is important to maintain a constant perfusion in the face of changes in blood pressure. It is reported to be impaired in pathologic states, including hypertension, cerebral infarction, and head injury. However, it is not clear whether cerebral autoregulation is impaired in resuscitated patients after cardiac arrest. Methods: Cerebral autoregulation in comatose patients after cardiac arrest was assessed by using an indirect method of cerebral blood flow (CBF). Eight patients who had cardiac arrest outside of the hospital and were successfully resuscitated in the emergency room were included in this study. A catheter was inserted percutaneously into the right internal jugular vein and positioned so that the tip was in the jugular bulb. Mean arterial pressure (MAP) was changed to a value of 30% lower or higher than baseline MAP by infusing trimethaphan or methoxamine, respectively. At each MAP level, arterial and jugular bulb venous blood gases were measured, and arterial-jugular bulb venous oxygen content difference (AVDO2) was calculated. Results: The 1/AVDO2 (CBFI) and oxygen saturation of jugular bulb venous blood (SjvO2) significantly decreased at the lower MAP level, and significantly increased at the higher MAP level. The ratio of the CBFI at the lower MAP level to the CBFI at baseline (CBFI-L/CBFI-B) inversely correlated with the Sjvo2 at baseline. Conclusions: Assuming that the cerebral metabolic rate of oxygen does not change during the interventions in MAP, the changes of CBFI and SjvO2 seen after the decrease or increase in MAP indicate that cerebral autoregulation was impaired in these resuscitated patients. The degree of the impairment of cerebral autoregulation may be secondary to the degree of brain injury caused by the cerebral ischemia accompanying cardiac arrest.

Obesity: an anaesthetic challenge.

Abstract: Some define morbid obesity as a doubling of the person’s predicted ideal weight (3), but ideally an index of obesity should be independent of height, muscularity and skeletal mass; in fact, it should reflect fatness only (4). A widely used method correlated to the relative amount of adipose tissue is the body mass index (BMI), the intention of which is to minimize the effect of height on weight:

Effects of posture and pneumoperitoneum during anaesthesia on the indices of left ventricular filling

Abstract: Background. Laparoscopic surgery requires the use of pneumoperitoneum (PP). When combined with positional changes, pneumoperitoneum may cause marked circulatory alterations. Methods. Eight anaesthetized cardiovascularly healthy patients, scheduled for laparoscopic cholecystectomy, were studied before and during pneumoperitoneum in three different postures (supine, Trendelenburg and reversed Trendelenburg), employing transesophageal echocardiography and pulmonary artery pressure monitoring. Results. PP significantly increased end-diastolic area (EDA) and pulmonary capillary wedge pressure (PCWP) irrespective of posture. PCWP was significantly influenced by postural changes, whereas EDA was not. Further, changes in EDA and PCWP covaried during the investigation, but showed no linear correlation. Systolic function, measured as end-systolic area (ESA) and fractional area shortening (FAS), was not altered. Diastolic function, as assessed by the velocity rate of the trans-mitral flow during the early filling phase (E) and the atrial contraction (A), showed no change of the E/A ratio, whereas after the induction of PP there was a significant reduction of the E component. Conclusions. In cardiovascularly healthy patients, the left ventricular volume is increased during pneumoperitoneum. Further, changes in invasive pressure determinations (PCWP) do not correlate linearly with changes in volume indices of left ventricular filling (EDA).

Reduced hypoxic chemosensitivity in partially paralysed man. A new property of muscle relaxants

Abstract: Background: It was hypothesized that non-depolarizing neuromuscular blocking agents impair hypoxic chemosensitivity in man. Methods: In thirty randomly allocated male volunteers the hypoxic and hypercarbic ventilatory responses were measured during partial paralysis (TOF ratio 0.70) due to either atracurium (n=10), pancuronium (n=10) or vecuronium (n=10). Results: Hypoxic ventilatory responses were depressed by 306, 287 and 296% (mean SD) at steady-state infusion of atracurium, pancuronium and vecuronium, respectively. At a TOF ratio of >0.90, the HVR was not different from control measurements. Conclusion: It is concluded that non-depolarizing neuromuscular blocking agents impair hypoxic ventilatory regulation. Further experimental studies are warranted to fully describe the mechanism(s) responsible for this interaction.

An audit of perioperative aspiration pneumonitis in gynaecological and obstetric patients

Abstract: Obstetric patients are considered to be at increased risk of anaesthesia-related Aspiration Pneumonitis. Less is known about the incidence and morbidity of this complication in younger women undergoing gynaecological surgery. We performed a 4-year audit of perioperative Aspiration Pneumonitis, defined as bronchospasm, hypoxia, cough and dyspnea, together with radiographic or auscultatory abnormalities, following a witnessed episode of gastric content entering the trachea or an intraoperative episode making pulmonary aspiration likely, in two larger Norwegian hospitals. Eleven cases were identified; 4 in Caesarean Section (C-section) patients, 5 in gynaecological (GYN) outpatients and 2 in GYN inpatients, with incidences of 0.11%, 0.04% and 0.01% respectively (P = 0.03). Risk factors were present in all patients. No patient died, but the short-time morbidity in the form of prolonged ICU stay and hospitalisation was significant. At discharge all patients noted symptoms of dyspnea, cough, and tightness of the chest; symptoms explainable by bronchial hyperreactivity. Five patients felt these symptoms did not disappear within 3 months and were followed up for a median of 2 years (range 4 months to 4 years). All were smokers and had multiple confounding causes, which made it hard to link their prolonged complaints directly to the pulmonary aspiration incident. All experienced improvement of symptoms during the follow-up period. Compared to gynaecological patients of similar age, C-section patients still have an increased risk of suffering Aspiration Pneumonitis. Prevention can be further improved in both groups. A cause-relationship between the incidence and respiratory complaints lasting longer than 3 months could not be established, and a structured follow-up may be helpful to avoid later medicolegal claims.

Atelectasis and pulmonary shunting during induction of general anaesthesia--can they be avoided?

Abstract: BACKGROUND Gas exchange is regularly impaired during general anaesthesia with mechanical ventilation. A major cause of this disorder appears to be atelectasis and consequently pulmonary shunt. After re-expansion, atelectasis reappears very slowly if 30% oxygen in nitrogen is used, but much faster if 100% oxygen is used. The aim of the present study-was to evaluate if early formation of atelectasis and pulmonary shunt may be avoided if the lungs are ventilated with 30% oxygen in nitrogen instead of 100% oxygen during the induction of general anaesthesia. METHODS Twenty-four adult patients with healthy lungs scheduled for elective surgery were investigated. During induction of anaesthesia, the lungs were manually ventilated via a face mask, using either 30% oxygen in nitrogen (group 1, n = 12) or 100% oxygen (group 2, n = 12). Atelectasis was estimated by computed x-ray tomography and ventilation-perfusion distribution with the multiple inert gas elimination technique, both awake and during general anaesthesia with mechanical ventilation. RESULTS No atelectasis was present in the awake subjects. After induction of anaesthesia, the mean amount of atelectasis was minor (0.2 +/- 0.4 cm2) in group 1 and considerably greater (8.0 +/- 8.2 cm2) in group 2 (P < 0.001). The pulmonary shunt was 0.3 +/- 0.7% of cardiac output in the awake subjects. This value increased to 2.1 +/- 3.8% in group 1 and to 6.5 +/- 5.2% in group 2 (P < 0.05). The indices of VA/Q mismatch showed no difference between the two groups. CONCLUSION During induction of general intravenous anaesthesia in patients with healthy lungs, gas composition plays an important role for atelectasis formation and the establishment of pulmonary shunt. By using a mixture containing 30% oxygen in nitrogen, the early formation of atelectasis and pulmonary shunt may, at least in part, be avoided.

Fasting guidelines in different countries

Abstract: Abstention from food and drink prior to anaesthesia remains a cornerstone in safe practice. Despite the lack of scientific support, previous guidelines, similar for fluids and solids, have for more than three decades more often than not recommended “nil by mouth” (“nothing-per-os”; “NPO” in the US) after midnight or a fixed duration of time. Based on an increased number of studies of relevance to the duration of preoperative fasting, reviews on this subject concerning both adults (1) and children (2) and a large number of editorials (3–7), have recently been published. Since there may be a discrepancy between conclusions based on scientific studies and the current routine practice - this presentation is intended to survey the current recommendations in different countries and how they relate to publications on the subject. Opinions are mainly derived from officers of associations linked to The World Federation for Anaesthesiologists (WFSA) and from current literature.

Balanced analgesia improves recovery and outcome after outpatient tubal ligation

Abstract: Outpatient surgery benefits patients only if postoperative sequelae are effectively treated. After laparoscopic tubal ligation (TL) intense pain and consequent postoperative nausea and vomiting (PONV) has been a problem delaying recovery and resulting in hospital admission. Ninety patients were randomised to this double-blind study, the aim being to evaluate the effect of balanced analgesia on postoperative pain and recovery after sterilization. The balanced analgesia group received 5 ml of 2% lidocaine gel on the sterilization clips and perioperatively 200 mg of ketoprofen i.v. The lidocaine group received 5 ml of 2% lidocaine gel on the clips and placebo i.v. perioperatively. The placebo group received 5 ml of placebo gel on the clips and placebo i.v. perioperatively. Infusion of propofol and 67% nitrous oxide in oxygen were used for maintenance of anesthesia. Succinylcholine and vecuronium were used for muscle relaxation and 0.1 mg of fentanyl i.v. was given to all patients at induction of anesthesia. Postoperative pain and analgesic requirements, incidence of PONV and need for antiemetic medication were all significantly lower in the balanced analgesia group. Home readiness was consistently achieved 70-90 min sooner in the balanced analgesia group compared to the other groups (P < 0.01 between the balanced analgesia and the placebo group), and the patients were able to return to normal activity sooner (cumulatively 93% of the patients in the balanced analgesia group vs. 60% in the other two groups (P < 0.01 between the balanced analgesia and the other groups) had returned to normal activity on the 2nd postoperative day). It is concluded that in patients undergoing laparoscopic TL the combination of analgesic regimens with different mechanisms of action offer a simple and efficient way of postoperative pain relief, as well as an improvement of quality (i.e. less PONV) and speed of recovery.

Lidocaine attenuates hyperoxic lung injury in rabbits

Abstract: BACKGROUND High concentrations of oxygen acute lung injury. Neutrophils are thought to play a pivotal role in the pathogenesis of this lung injury through the release of oxygen radicals, neutral proteases, and lysosomal enzymes. Lidocaine has been shown to inhibit neutrophil function. We examined whether intravenous pretreatment with lidocaine attenuated acute lung injury induced by hyperoxia. METHOD Twenty-seven anaesthetized male rabbits were allocated to receive one of three treatments (n = 9 for each group): ventilation with 100% oxygen for 36 h with and without lidocaine treatment, and ventilation with air for 36 h without lidocaine. In the lidocaine-treated group, a single intravenous lidocaine 2 mg/kg was administered immediately after the initiation of exposure to 100% oxygen; thereafter, the lidocaine was infused at a rate of 2 mg.kg(-1).h(-1) for 36 h until the animals were sacrificed. Haemodynamics, PaO2, and lung mechanics were recorded during the ventilation period. After exposure, the lung mechanics and cell fraction in bronchoalveolar lavage fluid (BALF) were measured and analyzed, as was the concentration of activated complements, and cytokines in BALF. The lung wet-to dry- (W/D) weight ratio and albumin concentrations in BALF were analyzed as an index of pulmonary oedema. We also compared the chemiluminescence of neutrophils isolated from the pulmonary artery, and light microscopic findings, in the three groups. RESULTS Pure oxygen for 36 h caused no significant changes in haemodynamics, lung mechanics, or PaO2/FiO2 ratio. However, hyperoxia significantly increased the lung W/D weight ratio, the influx of neutrophils into the lung, and BALF concentrations of C3a, C5a, TNF-alpha, IL-1 beta, and albumin. Lidocaine attenuated these increases (W/D ratio: 5.7 vs 5.1, %PMN: 19.2% vs 1.6%, C3a: 62 ng/dl vs 14 ng/dl, C5a: 7.9 ng/dl vs 4.1 nd/dl, TNF-alpha: 25 fmol/ml vs 2.8 fmol/ml, IL-1 beta: 36 fmol/ml vs 2.2 fmol/ml, and albumin: 9.5 mg/dl vs 2.8 mg/dl, all: P < 0.05). The chemiluminescence was increased in hyperoxic compared with in normoxic rabbits and lidocaine treatment attenuated the increase (opsonized zymosan stiluated: 3.7 x 10(6) cpm vs 2.3 x 10(6) cpm, P < 0.05). Exposure to 100% oxygen caused extensive morphologic lung damage which was lessened by lidocaine (lung injury score (mean): 3 vs 4, P < 0.05). CONCLUSION These findings suggest that intravenous lidocaine has a prophylactic effect on initial hyperoxic lung injury (pulmonary vascular permeability, histopathological, and biochemical BALF changes) in rabbits. The effects of lidocaine on more severe lung injury (decreased oxygenation) caused by hyperoxia for 72 h deserve further study.

Dural puncture: the patients' perspective A patient survey of cases at a DGH maternity unit 1983–1993

Abstract: Background: This study was designed to investigate the patient experience following accidental dural puncture complicating obstetric epidural analgesia. Methods: Sixty-three patients who had suffered from accidental dural puncture during obstetric epidural analgesia over a ten-year period were sent a questionnaire enquiring about their experiences. 68% responded. Results: Headache was the most severe symptom, occurring in 86% of this group; it lasted for a median of eight days and recurred after discharge in 47%. Backache occurred in 70% and 58% suffered with backache following discharge. Headache was considered to be the worst aspect by 49% of responders, backache by 19% and bedrest by 33%. Bed rest was frequently voluntary (as opposed to being enforced on medical orders) since many patients only gained relief from their headache when supine. Twenty patients (47%) received a blood patch, which was effective in relieving headache in 14 patients; however, the headache recurred after discharge in 10 of these 14 patients. Only 8 patients (19%) stated that they were aware of the risk of dural puncture prior to their epidural, three of whom were members of paramedical professions. Conclusions: Headache and backache are both common following dural puncture with a 16G needle and both frequently recur after discharge from hospital. It was the strongly expressed opinion of this selected group that all mothers should be warned of the risk of dural puncture before undergoing epidural analgesia.

Effect of pre- vs postoperative tonsillar infiltration with local anesthetics on postoperative pain after tonsillectomy.

Abstract: Background: Since pre-incisional peritonsillar infiltrations of local anesthetic solutions have been suggested to reduce postoperative pain after tonsillectomy, we compared the efficacy of either pre- or postoperative local anesthetic infiltration upon post-tonsillectomy pain. Methods: After the induction of general anesthesia, 68 consecutive healthy patients, ranging in age from 8 to 65 years, were randomly allocated to either receive peritonsillar infiltration with 0.25% bupivacaine (group 1) or normal saline (group 2) before incision. A third group (group 3) had their peritonsillar region infiltrated with 0.25% bupivacaine after the completion of surgery but before the patients were awakened from anesthesia. All the patients were treated in the same way in the postoperative period: NSAIDs were given intravenously to adults and rectally to children. Acetaminophen was given intravenously or rectally (children aged < 15 yr) if additional analgesic support was requested by the patient. Additional acetaminophen consumption was recorded daily. Pain scores were assessed on every patient with the use of a visual analogue scale (VAS) at rest, 1, 5, 9, 13, 17, 21 and 36 h after surgery, and also on swallowing during the first postoperative day. Results: Global VAS pain scores were lower in the groups treated with bupivacaine infiltration during the first 24 h after surgery (P < 0.05). Supplementary analgesic consumption was lower in group 3 than in group 2 during the 0–9 h interval immediately following surgery (P < 0.05). There were no statistically significant differences for any other parameters between the 3 groups. Conclusion: These results suggest that the timing of peritonsillar infiltration with bupivacaine is not of clinical importance and does not affect the quality of postoperative analgesia in patients undergoing tonsillectomy.

Recall of awareness during cardiac anaesthesia: influence of feedback information to the anaesthesiologist

Abstract: We interviewed 303 cardiac surgery patients to evaluate the incidence of intraoperative awareness with recall. First, we randomly interviewed 99 patients, of whom four patients (4%) reported awareness and recall. We informed the cardiac anaesthesiologists of the results of these interviews, and we also gave general information regarding means to reduce awareness and recall during general anaesthesia. Thereafter, we interviewed 204 consecutive cardiac surgery patients. Now, three of the patients (1.5%) had intraoperative awareness with recall. The reduction in the incidence from 4% to 1.5% was not significant. However, the doses of principal anaesthetic drugs had increased significantly between the two interview phases, while the dose of pancuronium, the main muscle relaxant used, had decreased significantly. Also, there was a significant increase in the number of anaesthesias where anaesthetic agents had been administered continuously instead of bolus or non-continuous dosing techniques. Between the patients with awareness and recall and those without it, there was no difference in the doses of anaesthetic agents given. The patients with awareness were significantly younger than those not aware. In conclusion, with educational measures and vigilance over the problem, the incidence of intraoperative awareness during cardiac anaesthesia may be reduced. The incidence figure of 1.5% we observed is of the magnitude reported recently by others with modern cardiac anaesthesia techniques.

Additive analgesic effect of codeine and paracetamol can be detected in strong, but not moderate, pain after Caesarean section

Abstract: Background: A randomized, double-blind, placebo-controlled single oral dose study was done in order to examine whether codeine has an additive analgesic effect to that of paracetamol for moderate and strong postoperative pain after abdominal surgery. The maximum recommended single dose of paracetamol 1000 mg (Paracet®) was compared with a combination of a submnximal dose of paracetamol 800 mg plus codeine 60 mg (Paralgin forte®) and placebo for pain relief after Caesarean section in 125 patients. Methods: Visual analogue pain intensity score (VAS 0–100 mm) and categorical pain relief score were recorded for 6 hours after the study drug intake. The main efficacy variables analyzed were: pain intensity difference and summed pain intensity differences during the first 3 and 6 h after study drug intake, total pain relief during the first 3 and 6 h, global evaluation score at the end of the observation period, and time to rescue analgesic. Results: Because of protocol violations, 17 patients were excluded from the analysis of effects. Among the 108 patients included in the analysis of analgesic effect, 49 patients had moderate baseline pain (VAS between 40 and 60 mm on a 100 mm scale), and 59 patients had strong baseline pain (VAS more than 60 mm). In patients with strong baseline pain, statistically highly significant differences were documented in efficacy variables between the active drugs and placebo and between the two active drugs. However, in patients with moderate baseline pain, no differences were found between the study drugs in any of the analgesic efficacy variables. Conclusion: This study thus confirms that codeine has additive analgesic effect to paracetamol in pain after surgery. Our results show the importance of initial pain intensity in postoperative assessment of analgesic drugs. Assay-sensitivity and test power are increased by selecting patients with sufficiently high initial pain intensity and by comparing groups of patients with identical surgery and similar demographic variables.

The effects of warming intravenous fluids on intraoperative hypothermia and postoperative shivering during prolonged abdominal surgery.

Abstract: BACKGROUND The infusion of several liters of crystalloid solution at room temperature may significantly contribute to intraoperative hypothermia because warming fluid to core temperature requires body heat. The aim of this study was to evaluate the effect of delivering warmed intravenous (IV) fluid to the patient on preventing intraoperative hypothermia. METHODS Intraoperative core and mean skin temperatures were measured during prolonged abdominal surgery in 18 patients randomly divided into two groups according to intraoperative IV fluid management. In 9 patients (control group) all IV fluids infused were at room temperature. In the other 9 patients (group receiving warmed fluids) all IV fluids were warmed using an active IV fluid tube-warming system. In all 18 patients a warming blanket covered the skin surface available for cutaneous warming. Intraoperative changes in total body heat content (kJ) were calculated from core and mean skin temperatures. RESULTS At the end of surgery, core temperature was 36.7 +/- 0.2 degrees C in the group receiving warmed fluids and 35.8 +/- 0.2 degrees C in the control group (P < 0.05). The estimated reduction in heat loss provided by warming IV fluid was 217 kJ, a value very close to the theoretical value expected from thermodynamic calculation. During recovery, one patient shivered in the group receiving warmed fluids and seven in the control group (P < 0.05). CONCLUSION In conclusion, infusion of warmed fluids, combined with skin-surface warming, helps to prevent hypothermia and reduces the incidence of postoperative shivering.

No additional analgesic effect of intra‐articular morphine or bupivacaine compared with placebo after elective knee arthroscopy

Abstract: Background: Intra-articular pain prophylaxis is a controversial measure, adding costs although the benefits are still disputed. We wanted to evaluate the effects of intra-articular opioid or local anaesthesia or a combination of the two on postoperative analgesia and analgesic consumption after elective knee arthroscopy. Methods: 107 patients with little or no preoperative pain and a minor surgical procedure were studied in a prospective, randomized double-blind design. The patients received midazolam 0.03 mg/kg intravenously before induction of general anaesthesia with fentanyl 1–2 μg/kg and propofol 2.0 mg/kg intravenously. Anaesthesia was maintained by a total intravenous technique with propofol infusion supplemented with alfentanil 10 μg/kg when needed. The patients breathed oxygen/air through a laryngeal mask. By the end of the surgery they received 20 ml of test drug into the knee-joint: Group I (BM): 20 ml of bupivacaine 2.5 mg/ml with 3 mg of morphine; Group II (B): 20 ml of bupivacaine 2.5 mg/ml; Group III (M): 20 ml isotonic saline with 3 mg morphine; Group IV (P): 20 ml of isotonic saline (placebo). Results: There were no significant differences between the groups in: time to first analgesic administered, analgesic consumption during the pre-or post-discharge period, nausea, somnolence, side-effects or postoperative pain perception during the first week. Conclusions: Intra-articular administration of morphine or bupivacaine is not indicated after elective knee-arthroscopy in patients with minor pre-operative pain and a small surgical trauma.

Systemic and central effects of morphine on gastroduodenal motility

Abstract: Gastrointestinal side effects still constitute a major drawback in both acute and chronic use of opioids. The exact mechanism behind the gastrointestinal effects is not known, but experimental studies indicate both central and peripheral actions. In an attempt to clarify to what extent the systemic effects of morphine after epidural administration contribute to the action on gastrointestinal motility, a study aiming to resemble the situation with epidural morphine was designed. Twenty healthy male volunteers were randomly allocated to two groups. Group one (n = 10) received intrathecal (0.4 mg) and intramuscular (4 mg) morphine (IT-IM-group). Group two (n = 10) received intrathecal (0.4 mg) morphine and i.m. saline (IT-group). Gastroduodenal activity was assessed by gastric emptying, manometry and electrogastrography. The plasma and urine concentrations of morphine and its inactive metabolite morphine-3-and active metabolite morphine-6-glucuronide were also determined. During the fasted state the gastrointestinal activity is characterised by a cyclic pattern with a duration of 80-120 min in the duodenum comprising three different phases with intense activity during Phase III. This pattern was seen in all volunteers. After the intrathecal administration the Phase III activity occurred significantly earlier in the IT-IM group (median 31 min; IR 34 min) compared to IT group (82 min; 37 min) (P < 0.01). The number of Phase IIIs was higher in the IT-IM group during the first 4 h after the morphine administration, compared to the IT group. However, after 6 h, there was no difference between the groups. The propagation velocity of Phase III decreased significantly in both groups (P < 0.001), but there was no difference between the groups. Tachygastria increased significantly with time in both groups. The acetaminophen absorption test showed that the area under the concentration curve (120 min) was significantly smaller in the IT-IM group compared to the IT group (P < 0.05). There were no measurable plasma concentrations of morphine or the glucoronidated metabolites M3G and M6G in the group that only received intrathecal morphine. This study showed that intrathecal morphine (0.4 mg) influenced gastroduodenal motility and that intramuscular morphine (4 mg) gave additional effects. These results might be applicable to the epidural situation and are indirect evidence that the gastroduodenal effects of epidural morphine are caused by both central and systemic effects of morphine.

Awareness in anaesthesia: Incidence, consequences and prevention

Abstract: Awareness during anaesthesia is a state of consciousness that is revealed by explicit or implicit memory of intraoperative events. Although large clinical surveys indicate an incidence of explicit awareness of < 0.3% during anaesthesia for general surgery, this adverse effect should be a great concern, because patients may be permanently disabled by the experience of being awake during surgery. Prevention of awareness during anaesthesia starts with an appropriate preoperative visit to the patient. The anaesthetic delivery machines must be properly checked before and during anaesthesia. The anaesthetic depth should be assessed by observation of movement responses, and consequently a minimum of muscle relaxants used. Because the anaesthetic depth can be controlled by determination of endtidal drug concentration, volatile inhaled anaesthesia may be associated with a lower frequency of awareness than other anaesthetic regimens.

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

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

Epidural and intrathecal opioids for postoperative pain management in Europe — a 17‐nation questionnaire study of selected hospitals

Abstract: Background: A questionnaire study conducted with the help of selected contact persons in 17 countries in Europe attempted to create a picture of the practice of acute pain management with the use of spinal opioid analgesia (SOA). Methods: A questionnaire was mailed to anaesthesiologists in 105 European hospitals. Depending on the population, 5–10 hospitals from each country were selected by a country co-ordinator. Results: A total of 101 (96.2%) completed questionnaires were returned. During 1 year SOA was used in 55117 patients (6.6% of all in-patient surgical procedures); of these, 89.2% received epidural opioids and 10.8% intrathecal opioids (ratio 8: 1). The most common opioid for SOA was morphine; fentanyl was also used quite frequently; 12 different opioids and 8 non-opioids had been used. ASA 1–2 patients receiving epidural morphine were nursed on surgical wards in 58.4% of the hospitals; in 25.7% of hospitals even ASA 3–4 were nursed on surgical wards. Respiratory depression (requiring naloxone treatment) was noted in 45 of the 49 183 patients who received epidural opioids (0.09%); 33 of these patients had received morphine. In more than 75% of hospitals the monitoring variables were respiratory rate, sedation level and pulse oximetry. There was a great difference between hospitals and countries regarding duration of monitoring. Conclusions: This questionnaire study showed that SOA was used in about 7% of 836 000 in-patients undergoing surgery at the 105 selected hospitals. Epidural opioids were used eight times more often than intrathecal opioids. Morphine was the commonest opioid for SOA. The duration of monitoring differed greatly between hospitals and countries; the need for official guidelines is emphasized.

Effect of P‐6 acupressure on prevention of nausea and vomiting after epidural morphine for post‐Cesarean section pain relief

Abstract: Background: Nausea and vomiting are important side effects following administration of epidural morphine for post-Cesarean section pain relief. Stimulation of the P-6 (Neiguan) acupoint is a traditional Chinese acupuncture modality used for antiemetic purpose; it has been found to be effective. The aim of this study was to evaluate the antiemetic effect of P-6 acupressure in parturients given epidural morphine for post-Cesarean section pain relief. Method: In a randomized, double-blind and controlled trial, sixty parturients receiving epidural morphine for post-Cesarean section pain relief were investigated. Parturients were allocated to receive the acupressure bands or placebo bands on the P-6 acupoint bilaterally before the administration of spinal anesthesia and were observed over a 48-hour study period. Results: The incidence of nausea and vomiting was significantly decreased from 43% and 27% in the control group, to 3% and 0% in the acupressure group, respectively (P <0.05). Conclusion: The results demonstrate that prophylactic use of acupressure bands bilaterally on the P-6 acupoint can significantly reduce incidence of nausea and vomiting after epidural morphine for post-Cesarean section pain relief.

Tourniquet release: systemic and metabolic effects.

Abstract: The pneumatic tourniquet produces ischemic changes in limbs. The effects of tourniquet release on systemic blood pressure and metabolic parameters were studied in 11 adult patients undergoing total knee replacement under general anesthesia. Mean arterial pressure (MAP) decreased rapidly after the release of the tourniquet, becoming significant at 3 min and remaining significantly depressed up to 15 min post release. Arterial pH, PaO2, PaCO2, lactate acid, and potassium changed significantly after the release, but normalized within 30 min. These results are notably different from a previous study in a similar patient population undergoing knee replacement under epidural anesthesia. Compared to patients under epidural anesthesia, patients receiving general anesthesia with mechanical ventilation are unable to compensate for the metabolic load caused by the tourniquet release, as the latter group are unable to alter their ventilatory rate. In elderly patients with decreased cardio-pulmonary reserve, this may be of clinical importance.

Morbidity and mortality associated with anaesthesia.

Abstract: The incidence of serious complications associated with Anaesthesia appears to have decreased in recent years. There are many reasons for this-better anaesthetic drugs and equipment, widespread availability of modern monitoring devices, improved standards of pre-, intra- and postoperative care, increasing interest in techniques to identify and control common risk factors and increased number of qualified anaesthetists. Nevertheless, accidents continue to occur. The most common cause of death or serious injury is still failure to ventilate the patient. All recent studies agree that the majority of accidents in modern practice are the consequence, not of equipment failure or adverse drug reactions, but of human error. Mistake, lack of vigilance, inexperience, inadequate supervision and failure of communication are identified as recurring problems. These problems need to be addressed if anaesthesia-related complications are to be further decreased. It seems reasonable to suggest that the use of anaesthesia simulators to train and test anaesthetists in difficult situations should be given a higher priority-both in basic training and in continued postgraduate education. Furthermore, since anaesthesia-related adverse outcomes are rare, strict safety procedures must be applied to thousands of patients in order to prevent one catastrophe. During times of increasing competition for health care money, anaesthetists must be resolute in defending and improving standards of training, monitoring and clinical care. Otherwise the substantial improvement in anaesthesia practice accomplished over recent years may quickly be lost again.

The Helsinki Declaration, research guidelines and regulations: present and future editorial aspects

Abstract: HE NUREMBERG code of 1947, the first international T document on research ethics, was a consequence of semnd world war experiments on unconsenting prisoners and detainees. The Declaration of Helsinki was promulgated in 1964 by the World Medical Association (l), and later revised three times (Tokyo, Venice, Hong Kong). It provides recommendations guiding physicians in biomedical research involving human subjects. The cornerstones are the requirements of informed consent of subjects, the distinction between clinical and non-clinical research and the ethical review of the research protocol. Research ethics committes (RECs) are established to ensure that biomedical research is done in accordance with the Helsinki Declaration. They guarantee high ethical standards and prevent the undertaking of unreasonable studies. RECs should protect research subjects from unacceptable risks associated with research. The handling of a study plan by the REC enforces the investigator to improve protocols, leading to higher scientific standards in biomedical research. As a consequence of the thalidomide tragedy of the 1 %Os, further regulations regarding biomedical research involving drugs have been introduced. Before starting clinical drug trials it is commonly required to obtain permission from a regulatory body, for instance the Food and Drug Administration (FDA) in the United States of America. In order to ensure the quality of such research, elaborate “good clinical practice (GCP)”guidelines have been introduced, for instance by the European Community (2). There are also regulations to secure confidentiality of research subjects. First, access to patient records is under strict regulation. Researchers or other third parties may have to obtain a permit to be granted access ta patient records. Furthermore, it is not a trivial undertaking to enter sensitive information into electronic data handling systems. Consequently, it is commonly required that permission is needed before such databases are established. The final important aspect in biomedical research involving human subjects is their right to compensation for accidental injury. This right is not acknowledged in all countries; however, most western countries probably have guidelines, recommendations or regulations to secure subjects their rights. It is important to be aware that all these regulations and guidelines in fact find their basis in the Declaration of Helsinki. Consequently, one may assume that physicians who are not conducting research in accordance with these regulations also violate the spirit of the Declaration of Helsinki. It should be noted, however, that there may be inherent conflicts between such guidelines and the Helsinki Declaration, for instance when guidelines require that research subjects have to waive their right to privacy before they are allowed to enter a clinical drug trial (3). What are the consequences of the above guidelines for the editorial process in Acta Anaesthesiologica Scandinavica? Our journal requires that research involving human subjects should be in accordance with the Declaration of Helsinki which states that “reports of experimentation not in accordance with the principles laid down in this Declaration should not be accepted for publication”.Thus we will generally reject studies which have not been reviewed by an appropriate research ethics committee. However, although a prerequisite, research ethics committtee approval does not automatically guarantee publication. Our editorial board has rejected studies that were found to be unethical, although approved by an ethics committee. On the other hand, it should be kept in mind that the Council for International Organisations of Medical Sci-