Spinal anesthesia hypotension in elective cesarean section in parturients wearing extra-strong compression stockings.

We have routinely applied an extra-strong graduated compression stocking to cesarean section patients to reduce the incidence of spinal anesthesia hypotension. Because bupivacaine has recently become available in Japan, we compared the incidence of spinal hypotension using either 2.0 ml of hyperbaric 0.3% dibucaine or 0.5% bupivacaine. There were 98 full-term parturients wearing the stocking who received 2.0 ml injection of dibucaine or bupivacaine for elective cesarean section. When systolic blood pressure decreased to 90-100 mm Hg or to less than 70% of the pre-anesthesia value, ephedrine was injected intravenously. There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the dibucaine and bupivacaine groups. Although the demographic data and various data related to anesthesia or surgery were similar in the groups, the fluid volume and the dose and incidence of ephedrine injection during anesthesia showed significant differences: the mean dose was 3.6 and 1.5 mg and the incidence was 41% and 19% in the dibucaine and bupivacaine groups, respectively. Spinal anesthesia using bupivacaine results in a lower incidence of spinal hypotension compared with dibucaine and, in combination with fitting the extra-strong stockings onto both legs, is clinically useful for cesarean sections.

Circulatory, respiratory and metabolic changes after thigh tourniquet release in combined epidural-propofol anaesthesia with preservation of spontaneous respiration.

Twelve elderly patients undergoing total knee arthroplasty received lumbar epidural anaesthesia and propofol infusion at 5 mg.kg(-1).h(-1) following a 1.5-2.0 mg.kg(-1) bolus dose with preservation of spontaneous respiration via a laryngeal mask airway. Circulatory, respiratory and metabolic variables were measured before and 1, 3, 5, 15 and 30 min after release of a pneumatic thigh tourniquet. The blood pressure was decreased at all time-points and the respiratory rate increased at 1 min. The P(a)CO(2) was increased only at 1 min. Arterial blood pH and base excess were decreased at 1 and 3 min and 1, 3 and 5 min, respectively. Arterial blood lactate levels were increased at all times. These characteristics were considered to be identical to those under regional anaesthesia with conscious spontaneous respiration, showing that spontaneous respiration under this anaesthetic regimen has a similar respiratory capacity to that of conscious spontaneous respiration.

Extra-strong graduated compression stocking reduces usage of vasopressor agents during spinal anesthesia for cesarean section.

Because a standard type of graduated compression stocking is not effective for the prevention of spinal anesthesia hypothension during cesarean section, we have used an extra-strong type of graduated compression stocking. This study examined whether the extra-strong stocking reduces usage of vasopressor agents. Forty-eight and 47 full term parturients were fitted with the standard stocking and the extra-strong stocking, respectively. Spinal anesthesia was performed by injecting 2.0 ml 0.3% dibucaine hyperbaric solution. When systolic blood pressure decreased to 90-100 mmHg or to less than 70% of the pre-anesthesia value, ephedrine was injected. There was no significant difference in systolic blood pressure or heart rate during spinal anesthesia between the groups. The mean dose of ephedrine injected during anesthesia was 12.2 and 4.3 mg, and the incidence of ephedrine injected was 85 and 49%, in the standard and extra-strong stocking groups, respectively. The extra-strong stocking group showed significantly lower values. Fitting the extra-strong stocking on both legs for cesarean sections undergoing spinal anesthesia reduced usage of vasopressor agents, suggesting a promising use of this stocking for non-invasive prophylaxis.

Increase of peak expiratory flow by atropine is dependent on circadian rhythm.

PURPOSE: To examine whether the bronchodilatory effect of atropine differs in the evening from the morning. METHODS: Thirteen adult healthy volunteers with no oral medication intake were studied. At 1600, peak expiratory flow (PEF) was measured three times, and the highest value recorded. Subsequently, the volunteer received 0.01 mg(-1) x kg(-1) atropine im, and the PEF was measured every 30 min for 180 min. On a different day, at 0400, the effect of atropine on the PEF was measured again in the same way. RESULTS: The PEF values before atropine at 1600 and 0400 were 485 +/- 92 (350-730) and 458 +/- 76 (340-600) 1 min(-1),(P < 0.05). There was no difference in PEF values between the 1600 and 0400 time courses after atropine. The PEF value was increased only at 90 min at 1600 (P = 0.0012), but at 30, 60, 90 and 120 min at 0400 (P = 0.0001). CONCLUSION: Atropine administration has a weak bronchodilatory effect in the evening, but a stronger effect in the morning. Airways are narrower in the morning than in the evening, and this change is inhibited by atropine such that the PEF values are restored to those observed in the evening.

Complement activation by propofol and its effect during propofol anaesthesia.

We have examined whether propofol activates complement. In the first study, blood was mixed with saline, propofol or the lipid solvent for propofol, and the activated complement 3 (C3a) and 4 (C4a) concentrations in the supernatant were assayed. In the second study, blood and propofol were mixed with various levels of nafamostat mesilate (anti-complement agent) up to 0.3 mmol/l and the C3a was assayed. In the third study, the time course of plasma C3a concentration in patients during propofol anaesthesia was examined. The results showed that the lipid solvent activated complement and produced similar levels of C3a to propofol, probably via both the classical and alternative pathways. This activation was not inhibited by any of the nafamostat concentrations used. There was no significant change in plasma C3a concentration during propofol anaesthesia. These results suggest that C3a is generated by the lipid solvent, but its accumulation during propofol anaesthesia is minimal.