Summary

Background and objective: To evaluate the effects of pneumoperitoneum and the reverse Trendelenburg position on respiratory mechanics and blood-gases in morbid obese patients with chronic obstructive pulmonary disease and hypertension.

Methods: Sixteen morbid obese patients with chronic obstructive pulmonary disease and hypertension were studied. Mean arterial pressure, heart rate, respiratory resistance, dynamic respiratory compliance and peak inspiratory pressures were measured at four time points: 5 min after induction of anaesthesia (T1), 5 min after insufflation of the peritoneum (T2), 5 min after adoption of a 20° reverse Trendelenburg position (T3), and 5 min after deflation of the peritoneum (T4). Arterial blood-gas status was measured at the same measuring points.

Results: Respiratory compliance was 40 ± 12, 28 ± 8, 32 ± 8 and 37 ± 11 mL cmH2O−1 in T1, T2, T3 and T4, respectively. The changes were significant at T2, T3 and T4. Airway resistance and peak inspiratory pressures showed comparable changes throughout the study with that of respiratory compliance. Haemodynamic measurements showed no clinically significant changes in this study.

Conclusions: In morbid obese patients with chronic obstructive pulmonary disease and hypertension, a 20° reverse Trendelenburg position improved respiratory mechanics and oxygenation without any apparent adverse effects on haemodynamics during laparoscopic gastric banding surgery.

Summary

Background and objective: The LMA-ProSeal® laryngeal mask airway is a new laryngeal mask airway with a modified cuff and drainage tube. We compared oropharyngeal leak pressure, intracuff pressure and anatomical position (assessed fibreoptically) for the Size 5 LMA-ProSeal® laryngeal mask airway and the classic laryngeal mask airway in different head–neck positions and using different intracuff inflation volumes.

Methods: Thirty paralysed anaesthetized adult male patients were studied. The LMA-ProSeal® laryngeal mask airway and the classic laryngeal mask airway were inserted into each patient in random order. The oropharyngeal leak pressure, intracuff pressure, and anatomical position of the airway tube and drainage tube (LMA-ProSeal® laryngeal mask airway only) were documented in four head and neck positions (neutral first, then flexion, extension and rotation in random order), and at 0–40 mL cuff volumes in the neutral position in 10 mL increments.

Results: Compared with the neutral position, the oropharyngeal leak pressure for both the LMA-ProSeal® laryngeal mask airway and the classic laryngeal mask airway was higher in flexion and rotation (all P ≤ 0.02), but lower in extension (all P ≤ 0.01). Changes in head–neck position did not alter the anatomical position of the airway tube or the drainage tube. The oropharyngeal leak pressure was always higher for the LMA-ProSeal® laryngeal mask airway (all P ≤ 0.005) and anatomical position better for the classic laryngeal mask airway (all P ≤ 0.04).

Conclusions: The anatomical position of the LMA-ProSeal® and the classic laryngeal mask airway is stable in different head–neck positions, but head–neck flexion and rotation are associated with an increase, and head–neck extension a decrease, in oropharyngeal leak pressure and intracuff pressure. The Size 5 LMA-ProSeal® laryngeal mask airway is capable of forming a more effective seal than the Size 5 classic laryngeal mask airway in males.

Summary

Background and objective: Total intravenous anaesthesia (TIVA) with ketamine–midazolam (KM) can be used for prolonged abdominal surgery. We compared this technique with halothane–nitrous oxide–oxygen anaesthesia using haemodynamic and endocrine stress responses as primary outcomes and adequacy of operating conditions and recovery profile as secondary outcomes.

Methods: Fifty adult patients undergoing radical cystectomy and bladder substitution were randomly assigned to receive either TIVA with KM (n = 25) or halothane, nitrous oxide and oxygen anaesthesia (n = 25). Invasive haemodynamic and oxygenation variables were monitored along with plasma cortisol and growth hormone concentrations. Operative conditions and recovery profiles were registered.

Results: Cardiac index and vascular resistance remained stable during and after surgery. Cortisol concentrations doubled during surgery and remained elevated in the recovery period. Growth hormone increased after induction, peaked during surgery and decreased during recovery. Neither the haemodynamic variables nor the plasma hormone concentrations differed significantly between the two groups. Intestinal loops were collapsed in the KM groups providing better operative conditions and a reduced need for postoperative analgesics.

Conclusions: The stress responses during KM anaesthesia for prolonged abdominal surgery were comparable to those during halothane–nitrous oxide–oxygen anaesthesia. However, KM anaesthesia provided better surgical conditions and better recovery.

Summary

Background and objective: This double-blind randomized study tested whether the addition of magnesium or ketamine to morphine for intravenous patient-controlled analgesia resulted in improved analgesic efficacy and lower pain scores compared with morphine patient-controlled analgesia alone after major abdominal surgery.

Methods: Ninety patients (3 × 30) were randomly allocated to receive either morphine 0.4 mg mL−1 (Group M) by patient-controlled analgesia, morphine 0.4 mg mL−1 + MgSO4 30 mg mL−1 (Group MM) or morphine 0.4 mg mL−1 + ketamine 1 mg mL−1 (Group MK). Postoperative analgesia was started when the verbal rating scale was ≥2. Patients were first given a standardized loading dose (0.05 mg kg−1) of the study solution. They were then allowed to use bolus doses of this solution (0.0125 mg kg−1 every 20 min without time limit). Discomfort, sedation, pain scores, cumulative morphine consumption and adverse effects were recorded up to 24 h after the start of the patient-controlled analgesia.

Results: The level of discomfort, level of sedation and verbal rating scores decreased significantly with time in all groups (P < 0.05). Both verbal rating and discomfort scores were significantly lower in Groups MM and MK at 15, 30 and 60 min compared with Group M (P < 0.001). Cumulative morphine consumption after 12 and 24 h was significantly higher in Group M alone (median 26 and 49 mg, respectively) compared with Group MM (24.2 and 45.7 mg) and Group MK (24.4 and 46.5 mg).

Conclusions: In the immediate postoperative period, the addition of magnesium or ketamine to morphine for intravenous patient-controlled analgesia led to a significantly lower consumption of morphine. However, these differences are unlikely to be of any clinical relevance.

Summary

Background and objective: Pain is often experienced when propofol is injected, and intravenous lidocaine is often effective in preventing such pain. We decided to determine whether metoprolol, given before the injection of propofol, is as effective as lidocaine in reducing the incidence and severity of the pain.

Methods: Ninety patients scheduled for elective surgery under general anaesthesia were randomly allocated to one of three groups to receive either metoprolol 2 mg, lidocaine 20 mg or saline 2 mL before any propofol was injected. Each patient was given one of these agents intravenously via a 20-G cannula on the dorsum of the hand whilst the venous drainage was occluded manually, at the middle of the forearm, for 45 s. After the occlusion was released, propofol 2.0–2.5 mg kg−1, at room temperature, was injected at 2 mL (20 mg) every 4 s. Pain was assessed verbally and scored as none (0), mild (1) or severe (2).

Results: The incidence of severe pain in the control group (56.7%) was significantly higher than in the metoprolol and lidocaine groups (16.6 and 10%, respectively). The number of patients who were free of pain was significantly higher in those who had been given either metoprolol or lidocaine.

Conclusions: Pretreatment with intravenous metoprolol was equally as effective as lidocaine in reducing the pain associated with propofol injection.

Summary

Background and objective: The visual analogue scale (VAS) is considered as the gold standard method for postoperative pain assessment. Nevertheless, in some clinical situations, this method may not be reliable. We performed an observational study to assess the use of the VAS and other pain scales by nurses in the postanaesthesia care unit.

Methods: We studied the reasons for not using the VAS and asked if it may be less appropriate in certain age groups.

Results: Among 600 patients included in the study (16% = 70 yr), nurses used the VAS in 53%, the numerical rating scale in 30%, the verbal rating scale in 12% and the behavioural scale in 5%. In 43% of the assessments, nursed did not use the VAS; the most frequently cited reason was related to their preference for other methods. In 54% of the assessments, the reason for not using the VAS was related to the patients, mainly when they were in too much pain to use it (22%). When the patient was in too much pain, the numerical rating scale was chosen in 54% and the behavioural scale in 27%. There was no difference between young patients and elderly patients.

Conclusions: Although the VAS is the standard method to assess pain, the nurses preferred using the numerical rating scale, both spontaneously or when VAS assessment was not possible.

Summary

Background and objective: Although many antiemetic drugs are available for intravenous use in the hospital setting, few are available after patient discharge. Consequently, nausea and vomiting are frequent complaints from patients at home after ambulatory surgery. We tested the hypothesis that the new 8 mg ondansetron disintegrating tablets will decrease the rate of nausea and vomiting at home after laparoscopic surgery.

Methods: Ninety-six patients were studied in a randomized double-blind study. Starting the first evening after operation and continuing every 12 h for 3 days, patients received either placebo or ondansetron 8 mg disintegrating tablets orally. The patients returned a questionnaire about postoperative nausea and vomiting, other side-effects, e.g. dizziness, headache, nightmare, anxiety and pain, as well as their overall satisfaction at 24 and 72 h after completion of surgery.

Results: The rates of nausea and vomiting were similar in the two groups, both during the first 24 h (28 versus 48%, placebo and ondansetron, respectively (ns) and during the 24–72 h (21 versus 35% (ns)). The incidence rate of vomiting was 8% (placebo) versus 12% (ondansetron) during the first 24 h (ns) and 9 versus 13% respectively in the 24–72 h (ns). No difference between groups was observed in overall satisfaction, incidence of postoperative pain or other side-effects.

Conclusions: The use of ondansetron disintegrating tablets of 8 mg twice a day for 3 days did not reduce the incidence of nausea and vomiting in patients undergoing outpatient laparoscopic surgery.

Summary

Background and objective: Statins are prescribed for patients with hypercholesterolemia. Atorvastatin is metabolized by cytochrome P4503A4 and inhibits P4503A4 activity in vitro. Alfentanil is a potent opioid used in clinical anaesthetic practice and is also metabolized by P4503A4. This study tested the hypothesis that chronic atorvastatin administration inhibits the metabolism of alfentanil.

Methods: Sixteen patients undergoing elective surgery were studied as matched pairs. One member of each pair was maintained on standard doses of atorvastatin for at least 4 months. Each patient received an alfentanil bolus (80 μg kg−1) intravenously (i.v.), followed by an alfentanil infusion (0.67 μg kg−1 min−1) for 90 min. Serial plasma alfentanil concentrations were measured using gas chromatography-nitrogen phosphorous detection. Pharmacokinetic parameters were calculated using two-compartment linear modelling.

Results: One patient and the corresponding match were excluded from the analysis. The elimination half-life of alfentanil was similar in the control and atorvastatin groups (98.8 ± 12.4 versus 98.3 ± 11.3 min, respectively). The clearance (Cl), volume of distribution at steady-state (Vdss) and area under the curve (AUC) were similar in the two groups (Cl = 0.20 (±0.06) and 0.22 (±0.04) L min−1, Vdss = 0.38 (±0.07) and 0.39 (±0.07) L kg−1, AUC = 0.05 (±0.02) and 0.04 (±0.01) mg min mL−1).

Conclusions: Concurrent atorvastatin administration does not alter the pharmacokinetics of alfentanil in patients undergoing elective surgery.

Summary

Background and objective: The study compared the analgesic efficacy and safety of two preoperatively administered cyclo-oxygenase-2 inhibitors, celecoxib and rofecoxib.

Methods: Ninety adult patients undergoing thyroid surgery were divided into three groups (each n = 30). They were given a single oral dose of placebo, celecoxib 200 mg or rofecoxib 50 mg 1 h before induction of anaesthesia. All patients received a standard anaesthetic. Intraoperative blood loss was measured. Pain scores, sedation scores, heart rate, mean arterial pressure and respiratory rate were noted at 0, 1, 2, 4, 6, 12 and 24 h postoperatively. Analgesic (meperidine) requirements and adverse effects were recorded during the first postoperative 24 h.

Results: Compared with placebo, pain scores were significantly lower with rofecoxib at all time points (P < 0.05) and were significantly lower with celecoxib (P < 0.05) during the first 4 h. Pain scores were significantly lower with rofecoxib compared with celecoxib at 6, 12 and 24 h (P < 0.05). The average cumulative 24 h meperidine dose was significantly lower with both celecoxib (54.9 ± 34.4 mg) and rofecoxib (42.8 ± 40.9 mg) compared with placebo (76.8 ± 6.2 mg) (P < 0.01 and P < 0.001, respectively). There were no differences in the intraoperative blood loss, heart rate, mean arterial pressure, respiratory rate, sedation scores and incidence of adverse effects among groups.

Conclusions: The preoperative administration of rofecoxib 50 mg and less so of celecoxib 200 mg provide a significant analgesic benefit with regard to postoperative pain relief and decrease in additional opioid requirements after thyroid surgery.

Summary

Background and objective: Perioperative hypothermia is generally regarded as undesirable, but its incidence rate in the elective procedures in our hospital and the effect of the preventative measures taken against it were unknown. An initial audit indicated that postoperative hypothermia occurred. Therefore, changes in practice were implemented to address the problem. A further audit was then undertaken to assess the impact of these measures.

Methods: The first audit recorded data from 177 patients undergoing major elective surgical procedures. Variables recorded were: ASA classification, duration of operation, use and description of preventative measures for hypothermia, blood loss, intravenous fluids, and core and peripheral temperatures on arrival and discharge from the recovery room. The subsequent audit included 158 patients undergoing major general, orthopaedic or vascular surgical procedures. Patients had core temperatures measured preoperatively, immediately upon arrival in the recovery room, and just before discharge back to the ward. Core temperatures in both audits were measured using an infrared temperature probe.

Results: The mean body temperature on arrival in the recovery room of patients in the initial audit was 35.5°C (range 32.2–37.2, SD ± 0.74), and in the subsequent audit 36.6°C (33.6–38.2, ±0.72). These differences reached significance (P < 0.0001). This was despite an average duration of surgery of 133.5 (25–330) min in the initial study compared with 154.7 (90–480) min subsequently.

Conclusions: We found that with simple but consistently implemented changes in practice, postoperative hypothermia in elective patients could largely be eradicated.