Anaesthesia and Intensive Care

The effect of propofol infusion on the stress response was studied in patients undergoing coronary artery bypass graft (CABG). Ten patients received propofol infusion during cardiopulmonary bypass (CPB) and ten controls received diazepam. Blood levels of Cortisol, adrenaline and noradrenaline were sampled. There was a significant reduction in all three hormones (P<0.05) in the study group. In addition, the amount of sodium nitroprusside used during CPB was significantly reduced (P<0.05).

The new antiemetic ondansetron is effective for the prophylaxis and treatment of postoperative nausea and vomiting (PONV), but has been subject to limited comparative evaluation in surgical inpatients. Two hundred and seventy women having abdominal gynaecological surgery were investigated for 24 hours postoperatively in a randomized, double-blind, placebo-controlled study of intraoperative intravenous ondansetron 8 mg (n=83), droperidol 2.5 mg (n = 89) or saline placebo (n=87). Patients receiving either ondansetron or droperidol remained likely to vomit, although the incidence was significantly reduced compared with placebo (72% and 83% versus 91%, P<0.01). Both drugs also resulted in significantly fewer vomiting episodes (P<0.001), lower nausea scores (P<0.05) and a lower incidence of patients requiring treatment for PONV (P<0.01). Compared with droperidol, the risk of vomiting after ondansetron was less (odds ratio 0.5, CI 0.3–1.0). Ondansetron resulted in fewer vomiting episodes (P<0.05) and a higher percentage of patients free of nausea after six hours postoperatively (P<0.05). In patients with a past history of PONV, both drugs had a similar short-lived antiemetic effect, reducing the incidence of vomiting and the need for treatment while in the recovery room, but not thereafter. Droperidol was associated with significantly less headache (P<0.05), but higher early sedation scores (P<0.05).

Although, compared to placebo, both droperidol and ondansetron administered intraoperatively reduced vomiting after major abdominal gynaecological surgery, the incidence during the first 24 postoperative hours was very high in all groups. Ondansetron reduced the risk of experiencing nausea after six hours postoperatively and the risk of vomiting, with respect to the total number of episodes, in the first 24 hours. It was no better than droperidol, however, in reducing the incidence of vomiting or the need for antiemetic treatment during the first postoperative day, whether or not patients had a past history of PONV.

This double-blind, randomized study was designed to evaluate the use of indomethacin (Indocid^®, MSD) following caesarean delivery performed under spinal anaesthesia. Thirty ASA I-II women presenting for elective caesarean were recruited. Spinal anaesthesia was performed in a standard manner using hyperbaric bupivacaine, fentanyl and morphine. At the completion of surgery, subjects were administered two rectal suppositories, followed by 12-hourly suppositories for six doses (three days). The study group received 100 mg indomethacin suppositories and controls were given placebo (Anusol^®).

Data collected included Visual Analog Scale (VAS) pain scores at rest and with movement, VAS scores for nausea and itch, and analgesic use.

Demographic data were similar in the two groups. Median time to first analgesia (TTFA) was nine hours in the control group v. 39.5 hours in the indomethacin group (P<0.003). Additional analgesic requests throughout the postoperative period were less in women who received indomethacin: 4 v 11 (P<0.001). Women who received indomethacin had significantly less pain on the first postoperative day, especially on movement: mean VAS 1.4 v. 5.1 (P<0.00001). There were no reported adverse neonatal or maternal effects from the use of indomethacin.

Rectal indomethacin use following caesarean delivery leads to significantly improved pain relief compared with placebo. The combination of spinal morphine and rectal indomethacin leads to high-quality postoperative analgesia.

A randomized study was carried out on 160 patients aged 30–60 years with the aim of finding a method of preventing postdural puncture headache (PDPH). In Taylor's lumbosacral approach to the subarachnoid space, two different needle sizes were used (21-gauge versus 25-gauge) for injecting the anaesthetic solution. Our results show an overall incidence of PDPH in nearly 8% of patients, with no significant difference related to the size of the needle employed. Patients with PDPH showed mild symptoms which disappeared in a short time and none needed epidural blood patching. The possibility of using larger needles, facilitating the execution of the block without increasing PDPH incidence, renders this technique particularly attractive in patients where the midline approach is not feasible, or when pencil-point needles are not available.

The efficacy of epidural corticosteroids in the treatment of sciatica was investigated by meta-analysis of all randomized controlled trials. Eleven suitable trials of good quality were identified involving a total of 907 patients.

The use of epidural (caudal or lumbar) steroid in the short-term (up to 60 days) increased the odds ratio (OR) of pain relief (>75% improvement) to 2.61 (95% CI 1.90–3.77) when compared with placebo. Despite some variations in trial characteristics there was little evidence of significant heterogeneity (P=0.07). When the trials were analysed for near or total relief of pain in the short-term the OR is 2.79 (95% CI 1.92–4.06), for heterogeneity (P=0.07). For longterm relief of pain (up to 12 months) the OR is 1.87 (95% CI 1.31–2.68).

Efficacy is independent of the route of injection; for caudal epidural steroid the OR is 3.80 (95% CI 1.36–10.6) and for the lumbar epidural steroid 2.43 (95% CI 1.77–3.74).

Adverse events included dural tap (2.5%), transient headache (2.3%) and a transient increase in pain (1.9%). There were no reported longterm adverse events.

In conclusion we present quantitative evidence from meta-analysis of pooled data from randomized trials that epidural administration of corticosteroids is effective in the management of lumbosacral radicular pain.

We investigated the accuracy of recycled gastric tonometer catheters, using a prospective laboratory model, within the Intensive Care Unit of a University teaching hospital.

Ten used tonometer catheters and three new catheters were exposed to known constant PCO₂ levels between 23–65 torr (3.06–8.66 kPa) in a gas mixing chamber, at a temperature of 35.5–38°C and a relative humidity >95%. The tonometer balloons were primed with normal saline, and after a 30-minute equilibration time, the saline was sampled for PCO₂ measurements. Steady-state PCO₂ (PCO_2(ss)) and gastric mucosal pH (pHi) values were derived using a correction factor and the Henderson-Hasselbalch equation.

There was no difference in the mean or distribution of PCO_2(ss) values between recycled and new catheters. The PCO_2(ss) values of recycled catheters were within the 95% confidence limits of those of new catheters. Individual catheter values did not differ significantly from each other (ANOVA P=0.05). Using an arterial HCO₃- value of 21 mmol/l, the calculated pHi values of used catheters varied <1.5% of the mean pHi of new catheters.

The tonometric performance of recycled gastric tonometer catheters was similar to that of new catheters when tested in vitro.

Two hundred and thirty-five consecutive Saudi patients aged between two and fifty-three years undergoing elective tympanoplasty (n = 32), septorhinoplasty (n = 68) or adenotonsillectomy (n=135) were studied. They were randomized to receive either a total intravenous anaesthetic (10 ears, 23 noses, 44 throats) consisting of propofol for induction of anaesthesia followed by a propofol infusion, a combined intravenous-inhalational anaesthetic (11 ears, 22 noses, 46 throats) consisting of the above with isoflurane in oxygen-enriched air, or a balanced inhalational anaesthetic (11 ears, 23 noses, 45 throats) consisting of thiopentone for induction of anaesthesia and oxygen in nitrous oxide with isoflurane for maintenance.

During tympanoplasty, all three anaesthetic techniques produced stable heart rates and arterial pressures. During septorhinoplasty, blood pressure rose in patients who received total intravenous anaesthesia, while combined and balanced techniques produced haemodynamic stability. During adenotonsillectomy, total intravenous anaesthesia produced a rise in both heart rate and blood pressure, the combined technique produced a rise in heart rate alone while balanced anaesthesia produced haemodynamic stability. Postoperatively, vomiting, pain scores and analgesic requirements were similar following all three types of anaesthetic within each surgical site subgroup.

Our findings support the choice of balanced inhalational anaesthesia for all three types of ENT surgery and, where cost and facilities permit, total intravenous anaesthesia for tympanoplasty and combined intravenous-inhalational anaesthesia for septorhinoplasty.

A prospective analysis of placement of left-sided plastic double-lumen tubes in 100 patients is presented. Intubation of the left bronchus was successfully accomplished using only auscultation and clinical signs (“blind” placement) in 91 patients. Double-lumen tubes were positioned in less than five minutes in 84 patients. The most common problem encountered (30%) was initial intubation of the right main bronchus. Seven of these patients required bronchoscopic assistance to guide the tube into the left bronchus. There were four minor intraoperative complications due to DLT malposition that were recognized and corrected by withdrawing the tube slightly back in the bronchus. The plastic double-lumen tubes functioned properly during the procedure in all 100 patients.

The incidence of gastro-oesophageal reflux in children undergoing general anaesthesia has not previously been studied. One-hundred-and-twenty children (ASA Class 1–2) were studied intraoperatively using continuous oesophageal pH monitoring. The incidence of reflux was 2.5% (3 of 120). None of these three patients had an adverse respiratory event. There was no correlation between reflux and adverse respiratory events. Thirteen patients had minor respiratory events without evidence of acid reflux. Gastro-oesophageal reflux does occur in healthy paediatric patients having minor surgery, but was not a significant cause of the adverse respiratory events that occurred in our study.

A Perioperative Service has recently been introduced at Liverpool Hospital, a 460-bed university teaching hospital. This provides a co-ordinated system for managing all elective surgical patients from the time an admission is booked until hospital discharge. This paper describes the patient assessment, structure and staff requirements, benefits of and problems encountered with this service.

The patient's preoperative preparation occurs before hospital admission. Where possible, patients are admitted on the day of procedure, either as a day-only patient, or a day-of-surgery patient. Patients are initially admitted to a specifically designed Perioperative Unit, adjacent to the Operating Theatre Suite. Patients do not enter the surgical wards until after their operation. Planning of the hospital discharge process commences at the time of booking for operation.

Introduction of the Perioperative Service was staged process commencing in mid-1992. The hospital admits approximately 6,400 elective surgery cases each year. From July 1992 to December 1994, day-only patients were approximately 45% of these cases. Day-of-surgery admission patients increased from 6% to 35% of all cases over the same period. Appproximately 22% of elective surgical cases were seen in the Perioperative Clinic.

As the Perioerative Service became fully operational, the average length of stay for elective surgical procedures fell. There has been a reduction in the areas of cancellations due to unavailablity of beds, inappropriate preparation of patients, and non-attendance of patients for booked procedures. Patient acceptance is high. The existence of a perioperative system facilitates the planning and management of elective surgery with maximum quality and efficiency.

Anaesthetists work as part of a process and deal with complex situations in their daily work. Considerable effort is put into training anaesthetists, but little has been done either in research or improving awareness of the intangible components of the anaesthesia system that affect safety, such as decision-making. The purpose of this article is to apply the principles of decision-making to anaesthesia practice.

One hundred combined spinal-epidural kits (Portex, n = 51, Mallinckrodt, n=49) were evaluated clinically by twelve anaesthetists with respect to performance of the loss-of-resistance syringe, epidural needle and spinal needle, and success in establishing single-segment combined spinal-epidural anaesthesia for caesarean section. Similar components included a plastic loss-of-resistance device, a Tuohy epidural needle, 26 or 27 gauge pencil-point spinal needle and closed end, three-lateral-eye epidural catheter. The Mallinckrodt kit incorporated a “back-eye” design for exit of the spinal needle from the epidural needle.

The epidural and subarachnoid spaces were satisfactorily identified on 98 occasions. Most anaesthetists preferred the Mallinckrodt kit packaging and the Portex loss-of-resistance syringe, although the latter may have been biased by familiarity with this device. The Portex spinal needle was more likely to be felt penetrating the dura (P=0.02) and aspiration of cerebrospinal fluid was more frequently described as easy (P=0.01). The most common criticisms of both kits were difficulty controlling the spinal needle position after entry into the subarachnoid space and subjectively, a high degree of resistance to injection through the spinal needle.

Infusion of fluids and drugs at very low rates may be necessary in neonatal intensive care. Marked haemodynamic fluctuations occurring during the infusion of inotropes have been shown to be due to the sticking of the plunger in the barrel of syringes used in syringe drivers. The Australian Therapeutic Goods Administration has recommended the use of volumetric or peristaltic pumps in these circumstances. We tested a number of infusion systems and found that 1. some syringes give continuous flow at low rates, and would be suitable for the delivery of inotropes, and 2. some infusion pumps provide non-continuous flow at low rates, and would not be satisfactory for the infusion of inotropes.