Summary

Background and objective: Metoclopramide is an antiemetic drug which inhibits plasma cholinesterase activity. We have compared the mivacurium infusion requirements and neuromuscular recovery after administration of metoclopramide to a group of adults compared to a control group.

Methods: Forty-five patients were randomized into three groups. Two groups received either 10 or 20 mg of intravenous (i.v.) metoclopramide and the third group received i.v. saline. Metoclopramide and saline were given 5 min before i.v. induction of anaesthesia. Plasma cholinesterase activity was measured before induction and 30 min after metoclopramide or saline injection. Neuromuscular block was monitored by accelerography using single and train-of-four (TOF) stimulation. The mivacurium intubation dose was followed by an infusion titrated every 5 min to maintain 95% block until the end of surgery when the infusion was stopped. Recovery from mivacurium was then monitored until complete.

Results: Mivacurium infusion rates were significantly lower in the metoclopramide groups. After 45 min of infusion, the infusion rates were 1.82 ± 0.8 and 2.1 ± 1 μg kg−1 min−1 in the 20 and 10 mg metoclopramide groups, respectively, and 6.8 ± 2.7 in the saline group. Time to recovery of TOF to greater than 90% was significantly prolonged in both metoclopramide groups compared to the saline group: 33.2 ± 7.2 and 29.5 ± 10.3 min in the metoclopramide 20 and 10 mg groups, respectively, compared to 22 ± 3.9 in the saline group (P < 0.001 for the 20 mg group compared to control).

Conclusion: Metoclopramide enhances the effect of a mivacurium infusion.

Summary

Background and objective: Xenon reduces the infarct size after regional ischaemia in the rabbit heart in vivo, but the underlying mechanisms are unknown. Since adhesion molecules on neutrophils are closely involved in the pathophysiology of ischaemia/reperfusion injury and modulation of neutrophil function, we investigated the effect of xenon on neutrophil adhesion molecule expression in vitro.

Methods: Freshly isolated neutrophils were incubated with 30% or 60% xenon for 60 min. In unstimulated and after stimulation with either N-formyl-methionyl-leucyl-phenylalanine or phorbol-12-myristate-13-acetate neutrophil surface expression of PSGL-1, L-selectin, CD11a and CD11b were measured by flow cytometry.

Results: At both concentrations, xenon reduced the surface expression of PSGL-1 by 10% (P < 0.05), and of L-selectin by 15% (P < 0.05) in the 60% xenon group. Furthermore, N-formyl-methionyl-leucyl-phenylalanine activated neutrophils showed an increased removal of L-selectin from the neutrophil surface following incubation with xenon (30% compared to controls, P < 0.05). Neutrophil β2-integrin expression was not altered by xenon.

Conclusions: Xenon increases the removal of the selectins PSGL-1 and L-selectin from the neutrophil surface in vitro. Since both selectins are involved in the initial contact between neutrophils and endothelial cells, xenon may affect neutrophil adhesion to endothelium during ischaemia/reperfusion injury. However, because the β2-integrin expression was unaffected by xenon, further investigations are required to clarify whether xenon may modulate neutrophil transmigration through endothelial cells in vivo.

Summary

Background and objective: The use of inhalation sedation with sub-anaesthetic concentrations of sevoflurane and nitrous oxide mixture is expected to reduce amounts of intravenous sedative drugs needed to produce a balanced sedation with the benefits of having reduced side-effects. Methods: Eighty-two patients requiring endoscopic and/or surgical procedures under conscious sedation and local anaesthesia were recruited for this pilot study. Conscious sedation was induced with a titrated dose of midazolam and propofol given intravenously until the clinical end-point of conscious sedation was achieved. Subsequently, during the procedure, the patient was asked to breathe sevoflurane 0.1–0.3% and a fixed ratio of 40% nitrous oxide in oxygen given through a face mask. Results: In 78 patients (95.1%), the treatment was completed successfully. Patients were discharged back to the wards within 4–16 min (10.1) without significant side-effects. Treatment was satisfactorily accepted by 38 patients (48.7%) and considered excellent by 40 patients (51.3%). Conclusions: The use of titrated doses of intravenous sedative drugs for induction of conscious sedation followed by the use of low concentrations (0.1–0.3%) of sevoflurane combined with 40% nitrous oxide for maintenance of conscious sedation in patients requiring endoscopic and/or surgical procedures under local anaesthesia, has the potential advantages of reducing amounts of intravenous sedative drugs, less likelihood of problems from drug side-effects and fast recovery and discharge time. Further investigations to establish the technique are currently in progress.

Newer anaesthetic agents provide a faster onset, easier titration and a more rapid recovery than the older agents, but are more expensive. In assessing the financial consequences associated with their use, it is important to examine the total costs (including personnel costs) and not just the acquisition costs of new drugs. Claims of cost savings from new drugs should be subjected to close scrutiny, with studies designed to demonstrate that the preferential use of the newer drug is associated with actual decreased payments for personnel, an earlier return to normal activities by the patient and/or their caretakers, or the completion of an additional case in the same operating session. It may be necessary to alter work patterns to obtain the full benefits of the new drugs (e.g. bypass of the labour-intensive [phase I] postanaesthetic care unit). Finally, greater cost savings in the operating room can be achieved by increasing efficiency in resource utilization. A delay in starting a case, or a prolonged turnover time between cases, can negate any cost savings related to the anaesthetist's choice of drugs.

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.

The Royal College of Anaesthetist requires that trainees wishing to specialise in Anaesthesia register with the College and keep a logbook documenting their experience and training in clinical anaesthesia. There are a number of advantages if such logbooks are kept in an electronic format. For the first time in the United Kingdom, we have evaluated the usefulness in a district general hospital of introducing a computerized system of record keeping based on a portable palm top computer. This has enabled the careful analysis of the individual work load of each trainee in the department by means of a specific program designed to generate a comprehensive report after the information from each individual has been downloaded on to a standard desk top computer. We have found a number of interesting and unexpected results and have highlighted ways in which the system may be improved.

We report a patient who suffered negative pressure pulmonary oedema because of tracheal obstruction after cryotherapy to granulation tissue in the trachea. The pathophysiology and clinical course of negative pressure pulmonary oedema is described. Though there are reports of negative pressure pulmonary oedema after airway obstruction, to our knowledge this is the first case reported after cryotherapy.

In order to prescribe appropriate analgesia for burns dressing changes the pain experienced by 30 burned patients during this procedure was recorded. Patients received analgesia prior to their dressing changes according to the current protocol in the burns unit. During the same period the medical and nursing staff in the unit who were involved in prescribing and administering the analgesia for the dressing change, were asked to assess the severity of pain that they thought patients experienced during dressing changes. Patients recorded their worst pain as none or mild in 64% of procedures. In contrast, no surgeon and only one nurse, rated pain as none or mild. The discrepancy between severity of pain recorded by patients and the pain predicted by staff prescribing and administering analgesia has clinical implications.

Summary

Background and objective: Patients having spinal anaesthesia with hyperbaric bupivacaine may become sensitive to sedative drugs but no data exists about any dose-related effect of the local anaesthetic on the sedative requirement. We aimed to investigate whether hyperbaric bupivacaine dose in spinal anaesthesia has any effect on midazolam requirements. Methods: Sixty unpremedicated patients were allocated to three equal groups. Patients in Groups I and II received hyperbaric bupivacaine 0.5% 10 and 17.5 mg respectively for spinal anaesthesia and Group III was a control group without spinal anaesthesia. In Groups I and II, after the evaluation of sensory block, patients received intravenous midazolam 1 mg per 30 s until the Ramsay sedation score reached 3 (drowsy but responsive to command). In Group III, general anaesthesia was induced after sedation score had reached 3 using midazolam. The total dose of midazolam (mg kg−1) given to each patient, the level of sensory block and complications were recorded. Results: The level of sensory block was higher in Group II (T7) than Group I (T9) (P < 0.01). The doses of midazolam were 0.063 mg kg−1 in Group I, 0.065 mg kg−1 in Group II and 0.101 mg kg−1 in Group III (P < 0.001). There was no correlation between level of sensory block and dose of midazolam in Group I (r = −0.293, P = 0.21) and Group II (r = 0.204, P = 0.39). Conclusions: Different doses of hyperbaric bupivacaine for spinal anaesthesia do not affect the midazolam requirements for sedation. However, spinal anaesthesia with hyperbaric bupivacaine with a maximum spread in the middle thoracic dermatomes may be associated with sedative effects and thus a reduced need for further sedation with midazolam.

Background and objective: The arterial thermodilution technique offers the ability to measure cardiac output using only central venous and arterial catheters. However, the technique has been reported to overestimate cardiac output because of a higher loss of cold indicator due to the increased distance between the sites of injection and measurement. In this study, the two techniques were compared with respect to conditions of low cardiac output in which a longer passage time may further increase loss of indicator.

Methods: Seventeen anaesthetized dogs were studied during hypovolaemic shock and fluid resuscitation. Cardiac output measurements were carried out simultaneously by arterial and pulmonary artery thermodilution techniques.

Results: One-hundred-and-two measurements were performed. The mean cardiac output was 2.28 ± 1.4 L min−1 by the pulmonary arterial technique and 2.29 ± 1.56 L min−1 by the arterial thermodilution technique. The correlation coefficient between the two measurements was 0.95, the precision −0.04 ± 0.41 L min−1 and the limits of agreement from −0.86 to 0.78 L min−1. The agreement was also consistent at low cardiac outputs.

Conclusions: The arterial thermodilution technique may serve as a less invasive cardiac output monitor in conditions of severe bleeding and shock.

The effectiveness of prochlorperazine buccal as an anti-emetic for the prevention of post-operative nausea and vomiting in patients using intravenous patient-controlled analgesia with morphine following abdominal hysterectomy has been assessed in a randomized, double-blind, placebo-controlled study. Forty-nine female patients participated with 26 allocated to the prochlorperazine buccal group and the remainder to the placebo group. Each received either placebo or prochlorperazine buccal 6 mg, in each case by the buccal route, 1 h prior to anaesthesia with further doses at 6, 18, 30 and 42 h, respectively. Symptom scores in respect of nausea, pain and sedation, the number without nausea, the number without vomiting and the requirement for rescue anti-emetic therapy were noted for each 4-h period during the 48-h study. Morphine utilization and taste associated with the study material were recorded. Data for 21 patients in the placebo group and 25 patients in the prochlorperazine buccal group were available for analysis. Patients in the prochlorperazine buccal group showed significantly lower mean nausea scores at 4–8 h (placebo group: mean nausea score 0.95; prochlorperazine buccal group: mean nausea score 0.36; P<0.05) and at 16–20 h (placebo group: mean nausea score 1.24; prochlorperazine buccal group: mean nausea score 0.48; P <0.05). Furthermore, the prochlorperazine buccal group showed significantly more patients without nausea at 4–8 h (placebo group: 11 patients out of 21; prochlorperazine buccal group: 20 patients out of 25; P<0.05) and at 16–20 h (placebo group: nine patients out of 21; prochlorperazine buccal group: 18 patients out of 25; P<0.05). The prochlorperazine buccal group showed a significantly higher number of patients rating the taste as unsatisfactory (placebo group: two patients out of 21; prochlorperazine buccal group: nine patients out of 25; P<0.05). Intravenous droperidol is the current gold standard prophylactic anti-emetic in post-operative nausea and vomiting associated with intravenous patient controlled analgesia with morphine usage. This study has demonstrated a peri-operative prochlorperazine buccal regimen to be effective in post-operative nausea and vomiting prophylaxis in the use of intravenous patient controlled analgesia with morphine. Prochlorperazine buccal should be considered as an effective, inexpensive option for the prevention of post-operative nausea and vomiting in post-operative intravenous patient controlled analgesia with morphine administration.

Since shunting is almost a purely mechanical treatment that radically affects pressure–volume compensation, patients’ cerebrospinal fluid hydrodynamics compensation should be examined before a shunt is implanted. Apart from an opening pressure and a resistance to cerebrospinal fluid outflow, pulse amplitude of intracranial pressure and the content of vasogenic waves are useful to gauge cerebrospinal fluid dynamics. Infusion studies, although invasive, may help with the decision about surgery. They also provide basic information for further management of shunted patients, when complications, such as shunt blockage, under- and over-drainage, arise.