In two consecutive, randomized, double-blind studies the effect of ondansetron on the time to induction of anaesthesia with propofol and, subsequently, thiopentone was assessed. In each study 40 patients received either ondansetron 8 mg or placebo immediately before induction of anaesthesia with a standardized dose of propofol (2.5 mg kg−1) or thiopentone (5 mg kg−1). Times to induction of anaesthesia were determined by assessing loss of verbal response, motor power and eyelash reflex. There was no difference in either study in times to induction of anaesthesia between immediate pre-treatment with ondansetron or placebo. Side effects were minor and of similar incidence in the ondansetron and placebo groups.
A 25-year-old man underwent left inguinal hernia repair. Following induction of anaesthesia, desaturation below 90% was noted which persisted despite correct placement of an endotracheal tube and ventilation with 100% oxygen. Surgery was allowed to continue, and the suspected diagnosis of pulmonary arterio-venous malformation was confirmed post-operatively by computerized axial tomography and arteriography. The investigation and treatment are described, and the diagnostic value of pulse oximetry in this case is emphasized.
Many currently used anti-emetics have significant sedative effects. These two studies were designed to investigate any interaction between ondansetron, a 5HT3 receptor antagonist anti-emetic, and thiopentone or propofol, on induction of general anaesthesia. After ethics committee approval, 40 unpremedicated female (ASA I & II) patients undergoing elective surgery were recruited to receive either ondansetron (hydrochloride dihydrate) 8 mg (5 min i.v. infusion) or placebo, immediately before induction of anaesthesia with thiopentone. Thiopentone 5 mg kg−1 was then administered over 30 s. If the eyelash reflex was still present 30 s later, thiopentone 25 mg (15 s−1 was administered until the reflex was abolished. In a similarly designed but separate study 40 unpremedicated female patients undergoing elective surgery received ondansetron 8 mg or placebo in a similar fashion, immediately before induction of anaesthesia with propofol. Propofol 2.5 mg kg−1 was then administered over 30 s. If eyelash reflex was still present 45 s later, propofol 10 mg 15 s−1 was administered until the reflex was abolished. End points for induction of anaesthesia (measured from end of main induction agent bolus) were: time to loss of verbal control (cessation of counting); time to loss of motor control (raised hand falling to side); time to loss of eyelash reflex. The times to responses and total doses of induction agent were analysed using Wilcoxon rank sum tests. There was no significant difference between the groups with regard to total doses of thiopentone or propofol used for induction of anaesthesia in the two studies. There were no significant differences between the groups in times to loss of verbal control, motor control or eyelash reflex. (Table 27)Table 27: (abstract 91). Effect of ondansetron on anaesthetic induction times Ondansetron does not interact with thiopentone or propofol to affect time to induction of anaesthesia. In these studies ondansetron was not found to have any sedative actions.
Gynaecological laparoscopy is a daycase procedure that can be associated with significant morbidity and patients may require admission to hospital for overnight stay. Following a decision to administer intraperitoneal bupivacaine routinely to such patients in our day surgery unit, we wished to establish whether this was routine practice elsewhere. We therefore carried out a postal survey of consultant anaesthetists in the UK who regularly anaesthetise patients undergoing daycase gynaecological laparoscopy, addressing a number of clinical issues. The results of the survey are presented, discussed and compared with published advice.
Summary A 74‐year‐old män developed complete loss of vision after transurethral prostatectomy under spinal anaesthesia. Eyesight returned to normal over the next 12 hours. A direct inhibitory effect on the retina caused by glycine absorbed with the irrigation fluid is suggested as a possible cause.
In two consecutive, randomized, double-blind studies the effect of ondansetron on the time to induction of anaesthesia with propofol and, subsequently, thiopentone was assessed. In each study 40 patients received either ondansetron 8 mg or placebo immediately before induction of anaesthesia with a standardized dose of propofol (2.5 mg kg-1) or thiopentone (5 mg kg-1). Times to induction of anaesthesia were determined by assessing loss of verbal response, motor power and eyelash reflex. There was no difference in either study in times to induction of anaesthesia between immediate pre-treatment with ondansetron or placebo. Side effects were minor and of similar incidence in the ondansetron and placebo groups.
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