Summary

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

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

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

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

Summary

Background and 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: Epidural vein cannulation has long been recognized as a problem in parturients due to distension of epidural veins. Epidural vein engorgement is maximal when the pregnant woman is in the supine position and minimal in the lateral position. Following an initial observation of an apparently high incidence of epidural vein cannulation in the sitting position, a randomized trial was conducted to document whether such an association existed.

Methods: A total of 209 term parturients were randomized to either the sitting or lateral position (107 left lateral, 102 sitting). Epidural catheter placement was achieved using a loss of resistance to air technique with an 18-G Tuohy needle. A data sheet was completed for each patient recording patient position, patient characteristics data, stage in labour and the incidence of epidural vein cannulation. Poor labour analgesia was defined as a visual analogue scale (VAS) >40 mm on a 0–100 mm pain intensity VAS.

Results: The risk of epidural vein cannulation was significantly higher in the sitting group (16 of 102 = 15.7%) compared with the lateral position group (4 of 107 = 3.7%), P = 0.011. There was a significant association between epidural vein cannulation and poor analgesia (P = 0.006). These two variables remained independently significant on multiple regression analysis (position, P = 0.009; analgesia, P = 0.006).

Conclusions: We conclude that there is a direct correlation between the incidence of epidural vein cannulation and patient posture during epidural catheter insertion in parturients.

Summary

Background and objective: The timing of interscalene block in relation to general anaesthesia remains a controversial subject. We believe that the results of our study demonstrate that this block may be performed safely on anaesthetized patients, providing that certain conditions are met.

Methods: Five hundred and forty-eight cases of arthroscopic shoulder surgery were analysed retrospectively in order to identify the results of interscalene block performed after induction of general anaesthesia, but before the start of surgery. Patients were kept in hospital for 24 h and assessed before being discharged from the hospital and again in the period from 4 to 8 weeks after surgery. Duration of the block, quality of postoperative pain relief and neurological complications were recorded.

Results: Our study failed to reveal any permanent or long-term neurological complications attributable to interscalene block performed after induction of general anaesthesia.

Conclusion: It is our opinion that the primary factor for safe interscalene block is modification of the anaesthetic technique rather than the timing of regional block in relation to induction of general anaesthesia.

Summary

Background and objective: The aim of the study was to report our experience concerning the effectiveness, complications and safety of spinal anaesthesia, and to determine whether spinal anaesthesia was effective in full-term infants undergoing elective inguinal hernia repair.

Methods: Sixty-eight full-term infants aged <6 months were included in the study. Infants were divided into three groups; Group I (<1 month, n = 20), Group II (>1 and <3 months, n = 26), and Group III (3–6 months, n = 22). All spinal blocks were performed under mask inhalation anaesthesia. A dose of bupivacaine 0.5% 0.5 mg kg−1 was used for infants under 5 kg and 0.4 mg kg−1 for those over 5 kg. Heart rate, mean arterial pressure, respiratory rate and SPO2 were recorded before and after spinal anaesthesia at 5 min intervals. Time to onset of analgesia, time to start of operation, duration of operation, anaesthesia and hospitalization, postoperative analgesic requirement and complications were recorded.

Results: Adequate spinal anaesthesia without sedation was better, time to obtain maximum cutaneous analgesia was shorter and need for sedation and postoperative analgesic requirement were significantly lower in Group I. Although heart rate, mean arterial pressure and respiratory rate decreased <20% in all groups following spinal analgesia, the decrease in Group I was lower than the others.

Conclusions: Spinal anaesthesia is an effective choice in inguinal hernia repair for full-term infants aged <1 month, providing excellent and reliable surgical conditions. However, this technique is not as useful for infants aged between 1 and 6 months.

Summary

Background and objective: ProSeal™ Laryngeal Mask Airway (PLMA) and Laryngeal Tube Suction™ (LTS), supraglottic airway devices allowing gastric drainage, were compared in this prospective, randomized study for airway management under conditions with elevated intra-abdominal pressure induced by capnoperitoneum.

Methods: Fifty patients undergoing elective gynaecological laparoscopic surgery were randomized to two groups of 25 each. After induction of general anaesthesia, devices were inserted, correct placement was verified, airway leak pressure was measured, and a gastric tube was inserted. Ease of insertion, quality of airway seal, risk of gastric insufflation and patient comfort were investigated.

Results: There were no differences in patient characteristics data for both groups. First-time insertion success rates were comparable for both groups: 92% – first attempt, 8% – second attempt for PLMA and LTS. Time until delivery of the first tidal volume for PLMA and LTS was 23.2 ± 6.1 and 23.5 ± 6.6 s, airway leak pressure was 45.4 ± 4.9 cmH2O and 45.6 ± 6.7 cmH2O with cuff pressures adjusted to 60 cmH2O. No gastric insufflation, gas loss or signs of regurgitation were detected. Placement of a gastric tube was successful in all patients. Patients were questioned for sore throat and dysphagia after removal of devices. Sore throat was stated in 1%/0% (PLMA) and 8%/4% (LTS) after 6/24 h, dysphagia in 4%/4% (PLMA) and 12%/4% (LTS).

Conclusions: Both devices provide a secure airway even under conditions of elevated intra-abdominal pressure. In this pilot study, no differences concerning handling or quality of airway seal were detected between PLMA and LTS.

Summary

Background: This study was designed to investigate the impact of patient age on propofol consumption and recovery time using a propofol–remifentanil anaesthetic standardized with Narcotrend™ EEG monitoring. The Narcotrend is a monitor for measuring the depth of anaesthesia based upon a six-letter classification from A (awake) to F (increasing burst suppression) including 14 substages.

Methods: In 200 patients scheduled for minor orthopaedic surgery Narcotrend EEG electrodes were positioned on the patient's forehead as recommended by the manufacturer. Anaesthesia was induced with remifentanil 0.4 μg kg−1 min−1 and 2 mg kg−1 propofol. Immediately after intubation remifentanil was reduced to a constant rate of 0.2 μg kg−1 min−1 whereas a propofol infusion was now started at 3 mg kg−1 h−1 and then adjusted accordingly to achieve a target Narcotrend stages of D0–2 indicating general anaesthesia. At the end of surgery the propofol and remifentanil infusions were stopped without tapering, the time to unstimulated opening of eyes was determined, and the propofol consumption (given as mg kg−1 h−1) was calculated from the total amount of infused propofol but without the induction bolus, from the actual body weight and the duration of propofol infusion. Furthermore, a linear regression analysis was applied for propofol consumption vs. age.

Results: The ages of the patients studied ranged from 16 to 83 yr old and patients were classified as ASA I–III. Propofol consumption significantly decreased with the patients' age: 30 yr of age or below the propofol consumption was calculated as 5.9 ± 1.7 mg kg−1 h−1, for 31–50 yr as 5.4 ± 1.8 mg kg−1 h−1, for 51–70 yr as 4.5 ± 1.7 mg kg−1 h−1 and above 70 yr as 3.5 ± 1.4 mg kg−1 h−1. Linear regression analysis revealed propofol (mg kg−1 h−1) = 9.136 − (0.0597 × age (yr)); R = 0.53. Concomitantly, the recovery time to opening of eyes increased with the patients' age: ≤30 yr, 7.4 ± 3.7 min; 31–50 yr, 9.5 ± 4.0 min; 51–70 yr, 9.8 ± 4.1 min; and ≥71 yr, 14.9 ± 12.1 min.

Conclusions: We conclude that with Narcotrend guidance, mean propofol consumption and recovery times are age dependent. However, as a result of large inter-individual variability, age per se does not allow a prediction of individual propofol need or recovery time.

Summary

Background and objective: The aim of this study was to compare cardiac output (CO) measurements by arterial trans-cardiopulmonary thermodilution (ATD) and pulmonary arterial thermodilution (PATD) with CO estimated on the basis of the Fick calculation via a metabolic monitor in septic shock.

Methods: In a prospective animal study 20 anaesthetized, ventilated pigs (20.9 ± 1.9 kg) were investigated. Septic shock was induced with faecal peritonitis. A pulmonary artery catheter was used for conventional measurement of CO. Simultaneously ATD was measured with a thermistor tipped catheter inserted into right carotid artery. Whole body oxygen consumption was measured by indirect calorimetry. Eighty data pairs of simultaneous CO measurements were analysed.

Results: CO measured with Fick and that measured with PATD were significantly correlated (r = 0.94, r2 = 0.87, P < 0.001). Mean CO measured by PATD was 94.3 ± 40.1 mL min−1 kg−1. Bias was 10.1 mL min−1 kg−1 (95% confidence interval (CI): 6.0–14.2 mL min−1 kg−1) with limits of agreement of −26.8 to 47.0 mL min−1 kg−1 . Correlation between Fick derived CO estimation and ATD CO was similar (r = 0.91, r2 = 0.83, P < 0.001). Mean CO measured by trans-cardiopulmonary thermodilution was 104.3 ± 43.2 mL min−1 kg−1 . Bias was 0.75 mL min−1 kg−1 (95% CI: −3.8 to 5.3 mL min−1 kg−1) with limits of agreement of −39.7 to 41.2 mL min−1 kg−1.

Conclusions: Even during haemodynamic instability in septic shock the correlation of arterial trans-cardiopulmonary thermodilution and PATD derived CO with direct Fick was good. As arterial trans-cardiopulmonary thermodilution is less invasive than PATD, the former may offer practical advantages.

Summary

Background and objective: Hypotension, especially in elderly and hypovolaemic patients, is frequently associated with intravenous midazolam administration. The mechanisms are not completely understood. This study was designed to investigate the mechanisms involved in the relaxing effect of midazolam on coronary arteries.

Methods: The substance was studied in isolated porcine coronary artery rings precontracted by either potassium chloride or prostaglandin F2α.

Results: Midazolam caused vasodilatation in a concentration-dependent manner. Relaxation was more pronounced in prostaglandin F2α precontracted segments than in those treated with potassium chloride (P < 0.001). Vasodilatation was unaffected by Nω-nitro-l-arginine, indomethacin and glibenclamide. Tetraethylammonium chloride, an inhibitor of the BKCa K+ channel (a high conductance Ca2+-sensitive K+ channel), dose dependently attenuated the vasodilating effect of midazolam (P < 0.01).

Conclusions: Hyperpolarization of the smooth muscle cell in the vessel wall, elicited by the activation the BKCa K+ channel, may contribute to the vasorelaxing effect of midazolam.

Summary

Background and objective: The degradation of the cytoskeletal protein microtubule-associated protein 2 (MAP2), by calpain has been known to occur following traumatic brain injury. We examined the therapeutic potential of calpain inhibitor 2, compared with that of moderate hypothermia in traumatic brain injury produced by weight drop in rats.

Methods: An inhibitor treated group (n = 8) received calpain inhibitor 2 intravenously (i.v.) for 5 min before and for 6 h after injury (total 2 μmol); a hypothermic (HT) group (n = 8) was maintained at 30°C (temporalis muscle temperature) for 45 min prior to and 60 min after injury; an untreated (UT) group (n = 8) received an infusion of inactive vehicle. Eight rats (sham group) underwent surgery without brain injury. Histopathological (haematoxylin and eosin staining) and MAP2 (immunohistchemistry and western blotting) evaluations were performed at 6 h after injury.

Results: Ipsilateral cortical damage was marked in the injured groups. In the hippocampus, marked pyramidal neuronal damage was observed in the UT and calpain inhibitor treated (CI) groups, while these neurons were better preserved in the HT group. The hippocampal MAP2 levels in the UT, CI and HT groups were significantly decreased to 13 ± 9%, 28 ± 33% and 62 ± 25% of the sham control, respectively. MAP2 concentration in the HT group was significantly higher than in UT and CI groups (P < 0.05).

Conclusion: The results suggest that moderate hypothermia, but not calpain inhibitor 2 with the tested regime, attenuates cytoskeletal damage in the ipsilateral hippocampus at 6 h after traumatic brain injury.

Summary

Background and objective: Magnesium disorders are common in hospitalized patients. In patients with low or normal magnesium, the intravenous magnesium loading test has been demonstrated to be a sensitive test to assess magnesium deficiency in critically ill patients. However, it is more time consuming and more difficult than the measurement of intracellular or extracellular magnesium concentrations. This study evaluated whether erythrocyte, plasma and urinary magnesium concentrations predict renal magnesium retention measured by the magnesium loading test.

Methods: One-hundred-and-three intensive care patients (36 females, 67 males) in a tertiary care centre and 41 healthy subjects (13 females, 28 males) took part in this prospective study. Intracellular, total plasma, ionized extracellular and urinary magnesium concentrations were measured and also magnesium retention by intravenous magnesium loading test.

Results: Total plasma magnesium concentration was poorly correlated with magnesium retention (r = 0.36, r2 = 0.13) and was the only parameter that significantly predicted magnesium retention in intensive care patients (P < 0.01). However, only 10% of the magnesium retention data were linked to the total plasma magnesium concentration.

Conclusions: Total plasma magnesium concentration predicts magnesium retention in critically ill intensive care patients but not intracellular and urinary magnesium concentrations. Only a small proportion of the magnesium retention was due to the total plasma magnesium concentration.