Profound vasodilatory hypotension in a patient with known empty sella syndrome following cardiac surgery.

A 63-year-old female with known empty sella syndrome underwent coronary artery bypass grafting surgery. She became hypotensive immediately postoperatively and this did not respond to fluid resuscitation and inotropic therapy. Surgical re-exploration was undertaken and did not reveal any surgical cause. Pulmonary artery catheterisation confirmed a profound vasodilatory component to her shock. We believe this was due to unmasking of posterior pituitary hypofunction, in particular vasopressin insufficiency, due to metabolic stress. This rapidly corrected with an exogenous vasopressin infusion.

Severe cardiovascular depression with remifentanil.

UNLABELLED: We compared the hemodynamic effects of a bolus administration of 1 microg/kg remifentanil for 1, 3, and 5 min (1, 0.33, and 0.2 microg. kg(-1). min(-1), respectively) in patients scheduled for coronary artery bypass grafting anesthetized with small-dose propofol. The study was terminated after only eight patients had been enrolled (three received remifentanil at a rate of 1.0 microg. kg(-1). min(-1), two at 0.33 microg. kg(-1). min(-1), and three at 0.2 microg. kg(-1). min(-1)) because of severe hemodynamic instability, which was particularly marked in four patients and consisted of severe bradycardia in one patient and severe hypotension with a reduction in systemic vascular resistance in three others. One patient showed evidence of myocardial ischemia. All patients responded to therapeutic interventions. The results show that remifentanil should be given only by slow infusion to such patients. IMPLICATIONS: This study investigates the effect on the heart and blood vessels of various rates of administration of boluses of a relatively new potent opiate, remifentanil, to patients with coronary artery disease. The results show that remifentanil should be given only by slow infusion to such patients.

Effects of omeprazole, with and without metoclopramide, in elective obstetric anaesthesia.

We report the results of a study comparing two dose regimens of the gastric antisecretory agent, omeprazole, used as prophylaxis against pulmonary aspiration of gastric contents during general anaesthesia for elective Caesarean section. Since antisecretory agents do not clear stomach contents already present at the start of treatment, two groups of patients who had received both omeprazole and a prokinetic drug, metoclopramide, were also studied. Thirty patients received oral omeprazole 40 mg on the evening before and on the morning of the operation (group 1), 33 received oral omeprazole 80 mg on the morning of the operation (group 2), and 15 (group 3) and 16 (group 4) patients respectively received the oral omeprazole doses stated above and in addition metoclopramide 10 mg given intramuscularly at least 20 min before induction of anaesthesia. Gastric aspirate pH and volume were measured at induction of anaesthesia and on completion of surgery. At induction of anaesthesia, treatment was judged successful (pH > or = 2.5 and volume < 25 ml) in 87%, 73%, 100% and 81% of patients in groups 1-4 respectively. The corresponding results on completion of surgery were 100%, 88%, 100% and 100%. While omeprazole is useful as prophylaxis against pulmonary aspiration during general anaesthesia for elective Caesarean section, the addition of a prokinetic agent seems to be necessary to maximise its effects.

Psychomotor and clinical assessment of flumazenil as an antagonist of midazolam.

The benzodiazepine antagonist flumazenil (0.01 mg/kg) has been compared with doxapram (1 mg/kg) and saline for the reversal of anaesthesia with intravenous midazolam, alfentanil, nitrous oxide in oxygen and isoflurane. The completeness of reversal was assessed by means of a four-choice reaction time test, 1 and 3 h following the antagonist. In addition, the level of sedation was graded using a five-point scale. Psychomotor testing showed that 60 min after administration of the antagonist, there were marked increases in reaction times (P less than 0.05) both in the control and doxapram groups, but not in those receiving flumazenil. At 180 min, however, reaction times in all groups had returned to baseline values. In contrast, there was a significant difference in the sedation scores between the saline and flumazenil groups throughout the study period (P less than 0.05). During the 4 h following midazolam, there was no evidence of re-sedation in any of the groups despite the relatively high midazolam dosage.

Effect of stimulation of the P6 antiemetic point on postoperative nausea and vomiting.

The antiemetic action of stimulation of the P6 (Neiguan) acupuncture (ACP) point has been studied in women, premedicated with nalbuphine 10 mg, undergoing minor gynaecological operations under methohexitone-nitrous oxide-oxygen anaesthesia. Invasive ACP--manual or electrical at 10 Hz--applied for 5 min at the time of administration of the premedication markedly reduced the incidence of vomiting and nausea in the first 6 h after operation, compared with untreated controls. This did not occur with stimulation of a "dummy" ACP point outside the recognized ACP meridians. Non-invasive methods (stimulation via a conducting stud or by pressure) were equally as effective as invasive ACP during the early postoperative period. However, both these non-invasive approaches were less effective than invasive ACP in the 1-6 h postoperative period, although each was as effective as two standard antiemetics (cyclizine 50 mg, metoclopramide 10 mg). In view of the total absence of any side effects in more than 500 ACP procedures, the clinical applications of this finding are worthy of further study.

A comparison between propofol and thiopentone as induction agents in obstetric anaesthesia.

Two comparable series of 21 patients who had elective Caesarean section had general anaesthesia induced by thiopentone sodium 4.53 (SD 0.65) mg/kg or propofol 2.15 (SD 0.26) mg/kg. Maintenance was similar for both groups. Blood pressure was lower in the propofol group during the induction-delivery interval. Umbilical/maternal vein ratios for thiopentone and propofol were 8.5 and 7.2 respectively. Infant wellbeing as judged by Apgar score and cord blood analysis showed little difference between the two induction agents. Factors associated with uterine relaxation and bleeding were similar in the two groups.