Summary

Background and objective: Previous work in our department, prior to the advent of digital subtraction angiography, showed that anaesthetist-administered sedation for cerebral angiography using propofol infusion–bolus fentanyl resulted in significantly more patients with early recall than a bolus fentanyl and midazolam technique. Our present study reassessed, 10 yr after our original study, the effectiveness of sedation for neuroradiological digital subtraction cerebral angiography, using three techniques currently in use in the department.

Methods: A total of 88 adult patients were sedated for neuroradiological angiograms by one of three anaesthetist-administered regimens: propofol–alfentanil infusion; boluses of fentanyl with a propofol infusion and boluses of fentanyl and midazolam. The latter two regimens had been used in our previous sedation study. Patients were assessed for time to orientation at the completion of the procedure, and followed up the next day to determine their last memory before sedation, first memory after the angiogram and any recall of the procedure itself.

Results: All three techniques were found to give satisfactory sedation and showed minimal difference in the time to orientation at the end of the procedure (3.7, 4.3 and 5.1 min), any awareness of the procedure itself (20% of patients overall) and numbers of patients having early recall; that is, recall of still being in the radiology department before return to the ward (22/29, 16/29 and 20/30).

Conclusions: Our results show that since the introduction of digital subtraction angiography we may have a different end-point of sedation compared to our original study, as well as a shorter angiogram time. Satisfactory anaesthetist-administered sedation can be provided for cerebral angiography by either infusion or incremental techniques. We feel that the success and safety of a sedation technique depends considerably on the skill and experience of the administrator such that these sedation techniques are only suitable for safe use by an anaesthetist.

Summary

Background and objective: Transurethral prostatectomy is routinely performed under spinal anaesthesia. This technique can cause hypotension, which is particularly undesirable in the elderly. The objective was to compare spinal anaesthesia for transurethral prostatectomy using hyperbaric bupivacaine 15 mg (control group) and hyperbaric bupivacaine 10 mg (limiting spread by maintaining the upright position for 15 min) and fentanyl 25 μg (fentanyl group) in terms of haemodynamic and pulmonary function.

Methods: Thirty ASA I–III patients were randomly selected and underwent spinal anaesthesia with either hyperbaric bupivacaine 15 mg (immediately positioned supine) or hyperbaric bupivacaine 10 mg (upright for 15 min) and fentanyl 25 μg.

Results: The greatest changes in mean arterial pressure (P = 0.9), ephedrine requirements (P = 0.8) and mean maximum change in forced vital capacity (P = 0.5) were similar in both groups.

Conclusions: The addition of fentanyl 25 μg to bupivacaine 10 mg and limiting the spread of the block does not improve either haemodynamic or pulmonary function compared with bupivacaine 15 mg in patients undergoing transurethral prostatectomy.

Summary

Background and objective: Intrathecal injections of the benzodiazepine midazolam have been reported to cause antinociception in animals and pain relief in human beings, including the potentiation of opioid analgesia. This study compared the efficacy of the addition of midazolam to a mixture of buprenorphine and bupivacaine used for spinal anaesthesia.

Methods: The study was prospective, randomized, and observer blinded. It involved 60 patients (30 per group), ASA I and II, age 20–40 yr, undergoing minor and intermediate lower abdominal surgery under spinal anaesthesia. Patients were randomized into two groups: the control group received a spinal injection of hyperbaric bupivacaine (15 mg) plus buprenorphine (0.15 mg) and the experimental group received a spinal injection of the same two drugs and doses but supplemented with intrathecal midazolam (2 mg).

Results: The duration of postoperative analgesia in the control group was 9.24 ± 2.57 h (mean ± SEM), and 21.33 ± 12.69 h in the midazolam treated group (P < 0.001). Patients treated with intrathecal midazolam had better pain relief judged by visual analogue score on coughing (P = 0.0013) and a nursing mobility score (P < 0.0001). Adverse effects were minor and their incidence was similar in both groups.

Conclusions: We conclude that intrathecal midazolam 2 mg improves the quality and duration of postoperative pain relief afforded by intrathecal buprenorphine and bupivacaine.

Summary

Background and objective: μ-agonistic opioids cause concentration-dependent hypoventilation and increased irregularity of breathing. The aim was to quantify opioid-induced irregularity of breathing and to investigate its time-course during and after an opioid infusion, and its ability to predict the severity of respiratory depression.

Methods: Twenty-three patients breathing spontaneously via a continuous positive airway pressure (CPAP) mask received an intravenous (i.v.) infusion of alfentanil (2.3 μg kg−1 min−1, 14 patients) or pirinitramide (piritramide) (17.9 μg kg−1 min−1, nine patients) until either a cumulative dose of 70 μg kg−1 for alfentanil or 500 μg kg−1 for pirinitramide had been achieved or the infusion had to be stopped for safety reasons. Tidal volumes (VT) and minute ventilation were measured with an anaesthesia workstation. For every 20 breaths, the quartile coefficient was calculated (Qeff20VT).

Results: Both the decrease of minute volume and the increase of Qeff20VT during and after opioid infusion were highly significant (P < 0.001, ANOVA). Patients in which the alfentanil infusion had to be terminated prematurely had lower minute volumes (P = 0.002, t-test) and higher Qeff20VT (P = 0.034, t-test) than those who received the complete dose. Changes in the regularity of breathing measured as Qeff20VT parallel those of minute ventilation during and after opioid infusion.

Conclusions: Opioids cause a more complicated disturbance of the control of respiration than a mere resetting to higher PCO2. Furthermore, Qeff20VT appears to predict the severity of opioid-induced respiratory depression.

Summary

Background and objective: In a retrospective study, we examined the suitability of a departmental clinical protocol for anaesthesia induction with target-controlled infusion of propofol developed for fibreoptic intubation in spontaneously breathing patients scheduled for outpatient oral surgery at the dental clinic of the Vienna University Hospital.

Methods: Propofol was administered using target-controlled infusion (Diprifusor®) at increasing target plasma concentrations starting at 2.5 μg mL−1. After 10 min, an intravenous dose of alfentanil (5–10 μg kg−1) was given for pain reduction. After a further 2 min, the patient was evaluated for response to auditory stimulation. If unresponsive, fibreoptic intubation was performed, otherwise the target concentration was increased by 0.2 μg mL−1 every 2 min until non-responsiveness was attained.

Results: Tracheal intubation was successful in all patients without any haemodynamic instability. However, one patient required facemask ventilation for 2 min. No patient was aware of intubation. The plasma concentration required for non-responsiveness was 2.8 ± 0.4 μg mL−1 (mean ± SD).

Conclusions: When using a target-controlled infusion of propofol, fibreoptic intubation can be performed with complete amnesia of the procedure for the patient. However, assisted ventilation of the lungs may be necessary as spontaneous ventilation may cease.

Summary

Background and objective: Advancing an uncut endotracheal tube into the right main bronchus produces unilateral breath sounds. We wanted to test the validity of using this method to distinguish oesophageal from tracheal intubation.

Methods: Forty-two patients were randomized into two groups. The first group was randomized to receive an endotracheal tube that was advanced into the right main bronchus. The second group of patients had their tracheas intubated as normal and then a second endotracheal tube was placed in the oesophagus. Blinded observers were then asked to decide by auscultation if the patients had unilateral breath sounds or not and if they were bronchial and therefore to decide if endotracheal intubation had occurred.

Results: Ninety-one per cent of patients (95% CI 0.71–0.99) intubated in the right main bronchus were correctly identified by unilateral breath sounds confirming the usefulness of this test.

Conclusions: Advancing an endotracheal tube into the right main bronchus and auscultation of unilateral breath sounds is a useful way of confirming tracheal intubation.

Summary

Background and objective: Gastrointestinal motility is influenced by abdominal trauma, laparotomy and particularly by intestinal ischaemia. The reflex inhibition of gastrointestinal motility is mediated mainly by the sympathetic nervous system. There are reports on the effects of systemically applied α2-adrenoceptor agonists on gastric emptying and recovery of bowel motility, but the effect of spinally applied α2-adrenoceptor agonists on intestinal motility has not been studied. The aim of this study was to investigate the effects of intrathecal medetomidine on gastrointestinal transit in rats after transient intestinal ischaemia.

Methods: Forty rats were randomly assigned to four groups of 10 each. Intrathecal catheter insertion and laparotomy were performed on each rat. Saline (10 μL) was injected intrathecally in Groups A and B. Medetomidine (10 μg in 10 μL) was injected intrathecally in Groups C and D. Intestinal ischaemia was induced in Groups B and D. Gastrointestinal transit was determined by measuring the length that a standardized marker meal of activated charcoal had travelled. Intrathecal medetomidine was compared to intrathecal saline in their effect on intestinal motility after 30 min period of bowel ischaemia.

Results: Laparotomy and intestinal ischaemia slowed gastrointestinal transit. Intrathecal medetomidine accelerated transit in both ischaemia and non-ischaemia groups.

Conclusion: Intrathecal medetomidine markedly accelerated small intestinal transit and may also hasten the recovery from post-ischaemic paralytic ileus.

Summary

Background and objective: The application of cricoid force is central to techniques that reduce the risk of gastric regurgitation and the subsequent pulmonary aspiration associated with obstetric and emergency anaesthesia. The discomfort associated with cricoid force in awake preoperative patients increases the incidence of coughing, struggling and pain during induction of anaesthesia. This study determined if increasing the surface area of a cricoid yoke reduced the associated discomfort in volunteers.

Methods: Fifty volunteers participated in a randomized single-blinded study. The cricoid yoke was positioned using standard anatomical landmarks and forces of 10, 20, 30 and 40 N were applied in a random order for 20 s, using two different yoke attachments with surface areas of 3 and 10 cm2. A rest of 30 s was allowed between the application of forces. Discomfort was graded by volunteers on a scale from 0 to 10 (0: no discomfort; 10: worse discomfort imaginable). A score of 10 was allocated if the volunteers could not tolerate the applied force for 20 s.

Results: Median scores for the small yoke were always higher than those for the large yoke at each force. There were significant differences between the scores for the small and large yokes at 10 and 20 N (P < 0.001) and 30 N (P = 0.0233), but there was no significant difference at 40 N.

Conclusions: The larger yoke was tolerated better by volunteers when clinically relevant cricoid forces were applied.

Summary

Background and objective: Intubation of the trachea has been a risky cross-contamination procedure over the past decade because no perfect decontamination procedures exist. Infectious agents found on laryngoscopic devices have the potential for devastating spread of the human immunodeficiency virus, hepatitis viruses B and C and transmissible non-conventional agents. The purpose of this prospective observational study was to assess the quality of endotracheal intubation with disposable laryngoscope blades, under normal intubating conditions.

Methods: Anaesthetists were asked to complete daily questionnaires regarding the difficulty of intubation experienced using the Vital View® disposable laryngoscope blade (Vital Signs Inc, Totowa, NC, USA). The choice of the type of blade (conventional or disposable blade) for the first attempt at intubation depended only on the operating room assignment. Glottic visualization during laryngoscopy was assessed by the modified Cormack and Lehane classification. Difficult tracheal intubation was evaluated by the intubation difficulty scale (>5, procedure involving moderate to major difficulty).

Results: The anaesthetic staff recorded 219 intubations. One hundred-and-nineteen of first attempts at laryngoscopy were with disposable blades (DB group) and another 100 with conventional blades (CB group). There were no significant differences between the two groups for Cormack and Lehane score 3, for intubation difficulty scale scores >5 and for intubation difficulty scale score 0. There were 12 blade changes before successful intubation.

Conclusions: In routine use, the Vital View® disposable laryngoscope blade appears to be an efficient device because it does not modify the ease of endotracheal intubation in most cases. Nonetheless, it may be advisable to maintain conventional laryngoscopes in reserve for difficult intubations.

Summary

Background and objective: This prospective, randomized, observer-blinded study compared onset time and duration of epidural anaesthesia produced by with levobupivacaine and ropivacaine for lower limb surgery.

Methods: ASA I–III adult patients undergoing elective lower limb procedures were randomized to receive epidural levobupivacaine 0.5% 15 mL (n = 30) or epidural ropivacaine 0.75% 15 mL (n = 35). A blinded observer evaluated onset time and regression of motor and sensory block, and intraoperative needs for fentanyl supplementation (0.1 mg intravenously).

Results: With levobupivacaine, onset time was 29 ± 24 min, with ropivacaine it was 25 ± 22 min (P = 0.41). Complete resolution of motor block required 105 ± 63 min with levobupivacaine and 95 ± 48 min with ropivacaine (P = 0.86). The time for regression of sensory block to T12 was 185 ± 77 min with levobupivacaine and 201 ± 75 min with ropivacaine (P = 0.46). Analgesic supplementation was required in one patient receiving levobupivacaine (3.5%) and in two patients receiving ropivacaine (5.7%) (P = 0.99).

Conclusions: In adults undergoing lower limb surgery, levobupivacaine 0.5% 15 mL produces an epidural block with the same clinical profile as ropivacaine 0.75% 15 mL.

Summary

Background and objective: The reported incidence of shoulder tip pain following laparoscopic surgery varies from 35 to 63%. This study evaluated the analgesic efficacy of either performing a prophylactic suprascapular nerve block with bupivacaine or applying a piroxicam patch to the skin over both shoulders for the relief of shoulder tip pain after laparoscopy.

Methods: Sixty healthy informed female patients were randomly assigned to one of three groups: (a) a control group (n = 20), no treatment; (b) a suprascapular nerve block group (n = 20) in which a bilateral suprascapular nerve block was performed before induction of anaesthesia with 5 mL 0.5% bupivacaine with epinephrine; and (c) a piroxicam patch group (n = 20) in which a 48 mg piroxicam patch on the skin of each shoulder was applied before induction of anaesthesia. All patients received a total intravenous anaesthesia technique with propofol, fentanyl and vecuronium. Shoulder tip and wound pain were recorded on a visual analogue pain scale at five time intervals for 24 h after surgery.

Results: A total of 80% of patients in the control group, 75% in the suprascapular nerve block group and 45% in the piroxicam patch group complained of shoulder tip pain during the recording period (P < 0.05). The scores for shoulder tip pain in the piroxicam patch group were significantly lower compared with the control group at 3, 6 and 12 h, and compared with the suprascapular nerve block group at 6 and 12 h. The need for analgesics was also significantly lower in the piroxicam patch group compared with the other two groups.

Conclusions: Prophylactic piroxicam patches are effective and safe for the relief of shoulder tip pain after laparoscopy. Bilateral suprascapular nerve block is not effective in this setting.

Summary

Background and objective: Levobupivacaine is the most recently introduced local anaesthetic into clinical practice. In a randomized double-blinded study, the onset, intraoperative tolerance, postoperative analgesic effect, motor blockade and any adverse reactions produced by levobupivacaine were compared with ropivacaine.

Methods: Sixty children, ASA I–II, 2–6 yr old, undergoing elective minor surgery, received a single caudal injection of 1 mL kg−1 of either levobupivacaine 0.25% or ropivacaine 0.25%. Caudal blocks were performed after induction of inhalation general anaesthesia using sevoflurane; anaesthesia was maintained via a laryngeal mask airway using a mixture of sevoflurane, oxygen and air.

Results: Onset time, intraoperative tolerance, postoperative analgesic effect and motor blockade were comparable between the two groups. The mean onset of the block was 8.2 ± 2.2 min for levobupivacaine and 8.5 ± 3.0 min for ropivacaine (P = 0.66). Additional analgesics during operation were not required in any of the children. No significant difference was found for mean time to requirement of additional analgesia with rectal acetaminophen (paracetamol) (302 ± 29 min for the levobupivacaine group and 230 ± 38 min for the ropivacaine group (P = 0.32)). During the first 4 h after placement of caudal block, the pain assessment score (according to the Children Hospital Eastern Ontario Pain Scale) was comparable for the two groups. No motor block was observed in any group on awakening, nor during the observation period.

Conclusions: We conclude that levobupivacaine 0.25% 1 mL kg−1 provides caudal block of comparable onset and duration, as produced by the same volume and concentration of ropivacaine.

Summary

Background and objective: This prospective, randomized study was conducted to compare unilateral spinal block using small doses of hyperbaric bupivacaine and single-agent anaesthesia with sevoflurane in elderly patients undergoing hip surgery.

Methods: Thirty patients (>65 yr) undergoing hip fracture repair were randomly allocated to receive unilateral spinal anaesthesia with hyperbaric bupivacaine 7.5 mg 0.5% (Group Spinal, n = 15) or volatile induction and maintenance anaesthesia with sevoflurane (Group SEVO, n = 15). General anaesthesia was induced by increasing the inspired concentration to 5%. A laryngeal mask airway was placed without muscle relaxants, and the end-tidal concentrations of sevoflurane were adjusted to maintain cardiovascular stability. Hypotension (decrease in systolic arterial pressure >20% from baseline), hypertension or bradycardia (heart rate < 50 beats min−1) requiring treatment, and the length of stay in the postanaesthesia care unit was recorded. Cognitive functions were evaluated the previous day, and 1 and 7 days after surgery with the Mini Mental State Examination test.

Results: Hypotension occurred in seven patients of Group Spinal (46%) and in 12 patients of Group SEVO (80%) (P = 0.05). Phenylephrine was required to control hypotension in three spinal patients (21%) and four SEVO patients (26%) (n.s.). SEVO patients had lower heart rates than spinal patients from 15 to 60 min after anaesthesia induction (P = 0.01). Bradycardia was observed in three SEVO patients (22%). Discharge from the postanaesthesia care unit required 15 (range 5–30) min in Group Spinal and 55 (15–80) min in Group SEVO (P = 0.0005). Eight patients in Group Spinal (53%) and nine patients in Group SEVO (60%) showed cognitive decline (Mini Mental State Examination test decreased ≥ 2 points from baseline) 24 h after surgery (n.s.). Seven days after surgery, confusion was still present in one patient of Group Spinal (6%) and in three patients of Group SEVO (20%) (n.s.).

Conclusions: In elderly patients undergoing hemiarthroplasty of the hip, induction and maintenance with sevoflurane provide a rapid emergence from anaesthesia without more depression of postoperative cognitive function compared with unilateral spinal anaesthesia. This technique represents an attractive option when patient refusal, lack of adequate co-operation or concomitant anticoagulant therapy contraindicate the use of spinal anaesthesia.

Summary

Background and objective: Headache is a common and distressing morbidity associated with day case surgery. We undertook a prospective, observational study to identify risk factors associated with perioperative headache in a modern, day case surgery setting.

Methods: Two hundred-and-thirty consecutive patients presenting for day case surgery were invited to complete a questionnaire about their previous experience of headache and various associated risk factors. Questionnaires were completed by 90% of patients. The presence of headache in the pre- or postoperative period was also documented. We used multivariate logistic regression to model perioperative headache.

Results: Increased frequency of previous headache, odds ratio (95% confidence interval) 1.9 (1.2–2.8) (P = 0.004) and low alcohol consumption 0.90 (0.87–0.98) (P = 0.019) were significant predictors. A history of migraine showed a trend towards being predictive 1.9 (0.9–4.0) (P = 0.055). Some risk factors thought to be important such as caffeine withdrawal and duration of starvation and fluid deprivation were not associated with perioperative headache in this setting.

Conclusions: In this study of risk factors associated with perioperative headache in day case surgery, increased frequency of headache and low alcohol consumption were independent risk factors.

Summary

Background and objective: A variety of drugs and techniques have been introduced into ambulatory anaesthesia. The technique as well as the drugs used may hasten or delay home discharge. We compared recovery profiles and side-effects of spinal anaesthesia and total intravenous anaesthesia.

Methods: Forty unpremedicated ASA I–II patients (18–65 yr) undergoing varicocele repair were randomly divided into two groups. Spinal anaesthesia (26-G atraumatic needle) with hyperbaric bupivacaine 0.5% 5 mg and fentanyl 25 μg were given to patients in Group Spinal (n = 20). Patients in Group TIVA (n = 20) received total intravenous anaesthesia with propofol and remifentanil given by continuous infusion; a laryngeal mask was used to secure the airway. The duration of surgery, time to home readiness and side-effects were recorded.

Results: The two groups were comparable with respect to patients' characteristics and duration of surgery. The times to achieve ambulation were similar between groups (Spinal = 78.4 ± 40.9 min, TIVA = 75.9 ± 13.8 min). Urinary voiding was a requirement for discharge after spinal anaesthesia and the time for home readiness was longer in Group Spinal (158.0 ± 40.2 versus 94.9 ± 18.8 min) (P < 0.05). Two patients reported pruritus and one reported postdural puncture headache in Group Spinal, whereas two patients reported nausea in Group TIVA. Patients in Group TIVA had a greater need for analgesia postoperation (P < 0.05).

Conclusions: In healthy unpremedicated men undergoing minor urological operations, total intravenous anaesthesia with remifentanil and propofol provided as safe and effective anaesthesia as spinal block with the advantage of earlier home readiness.

Summary

Background and objective: In recent human and animal studies, intrathecal administration of various doses of neostigmine produces analgesia without neurotoxicity. The aim was to examine the effects of intrathecal neostigmine and bupivacaine in patients undergoing perianal surgery under spinal anaesthesia.

Methods: The patients were randomly allocated into three groups of 15: Group 1 (controls) received hyperbaric bupivacaine 10 mg + dextrose 5%, 1 mL, to a total volume of 3 mL; Group 2 received hyperbaric bupivacaine 10 mg + neostigmine 25 μg in dextrose 5%, 1 mL, to a total volume of 3 mL; and Group 3 received hyperbaric bupivacaine 10 mg + neostigmine 50 μg in dextrose 5%, 1 mL, to a total volume of 3 mL.

Results: The onset of sensory block was significantly earlier for Group 2 and 3 patients compared with Group 1 patients (P < 0.05). The full time to recovery of motor block and sensory block was significantly longer in Group 3 compared with Group 1 (P < 0.05). In Group 3, the average time until the first dose of tramadol was longer than Group 1 (P < 0.05). The incidence rate of nausea and vomiting was significantly higher in Groups 2 and 3 than in Group 1 (P < 0.05).

Conclusions: The use of intrathecal neostigmine as an analgesic drug in perianal surgery is unsatisfactory because of prolonged motor blockade and nausea.

Summary

Background and objective: Spinal cord stimulation has been used successfully for many years in the management of neuropathic pain. Nociceptive pathways are closely integrated into many autonomic reflexes. The aim was to test the hypothesis that pain relief caused by spinal cord stimulation is related to changes in peripheral skin blood flow.

Methods: Twelve patients with spinal cord stimulators implanted as a treatment for neuropathic pain were entered into the study. Laser Doppler perfusion scanning was used as a direct method for selective measurement of changes in skin (peripheral) blood flow. Measurements were taken before and after the onset of spinal cord stimulation over the site of its sensory projection. The degree of pain relief due to spinal cord stimulation and the skin temperature of each patient were also recorded.

Results: Apart from one patient, spinal cord stimulation did not change skin blood flow in a statistically significant manner.

Conclusions: Pain relief due to spinal cord stimulation is not related to changes of skin blood flow.

Summary

Background and objective: In a randomized, placebo-controlled, double-blind trial, we compared the efficacy of oral dolasetron and ondansetron in preventing postoperative nausea and vomiting in children after various surgical operations.

Methods: Children were assigned randomly to one of three groups (each contained 50 children) to receive dolasetron 1.8 mg kg−1 or ondansetron 0.15 mg kg−1 orally, or a placebo. All children received methylene blue capsules (10 mg) orally as an indicator before the induction of anaesthesia. Postoperatively, contamination of the mouth and the endotracheal tube by methylene blue was recorded, and postoperative nausea and vomiting was recorded for 0–1, 1–24 and 0–24 h. Metoclopramide (0.1 mg kg−1) intravenously was used as the rescue antiemetic.

Results: In the 0–1 h period after operation, there were no differences between the groups. In the 1–24 h period, dolasetron was significantly better than placebo (nausea 8 versus 24%; vomiting 4 versus 20%; total nausea and vomiting scores 16 versus 48%). Over the 0–24 h period, both dolasetron and ondansetron were significantly better than placebo (nausea 16 versus 26 versus 40%), vomiting (8 versus 16 versus 30%), and total nausea and vomiting scores (32 versus 48 versus 78%). There were no significant differences between dolasetron and ondansetron. There was no important methylene blue contamination, and little use of rescue metoclopramide. There were no important adverse events.

Conclusions: Prophylactic oral dolasetron and ondansetron were effective in reducing postoperative nausea and vomiting in children.