Oculocardiac reflex and postoperative vomiting in paediatric strabismus surgery. A randomised controlled trial comparing four anaesthetic techniques.

BACKGROUND: Oculocardiac reflex (OCR) and postoperative vomiting are major complications of paediatric strabismus surgery. METHODS: Children (3-16 yr) undergoing elective strabismus surgery as inpatients were randomly allocated to four anaesthetic techniques: (A) thiopentone induction and isoflurane maintenance; (B) as (A) plus ondansetron 5 mg x m(-2) i.v.; (C) propofol induction and maintenance; (D) as (C) plus lignocaine 2 mg x kg(-1) i.v. All children received prophylactic atropine 0.02 mg x kg(-1) and alfentanil. Nitrous oxide was omitted. RESULTS: Data on 157 children were analysed. The cumulative incidence of vomiting within 6 and 24 h after surgery with thiopentone-isoflurane was 26% and 46%, respectively. Adding ondansetron decreased the incidence to 8% and 33%, respectively. This improvement was significant within 6 h only; the number-needed-to-treat was 5.5 (95% CI 2.9-46). Propofol was not different from thiopentone-isoflurane. The addition of lignocaine to propofol was of no benefit. The risk of an OCR was significantly increased with propofol (incidence 40%) compared with isoflurane (14%); the number-needed-to-harm was 3.9 (95% CI 2.6-8). CONCLUSIONS: Thiopental-isoflurane-air/O2-alfentanil resulted in a moderate risk of vomiting. Adding ondansetron significantly decreased this risk, but 6 children have to be treated for one to benefit in the early postoperative period. Propofol and propofol-lignocaine showed no benefit on vomiting but significantly increased the risk of an OCR despite high-dose prophylactic atropine.

Sensory changes and pain after abdominal hysterectomy: a comparison of anesthetic supplementation with fentanyl versus magnesium or ketamine.

UNLABELLED: Drugs interacting with opioid or N-methyl-D-aspartate (NMDA) receptors may have differing effects on post-surgical sensory changes, such as central inhibition or spinal excitation. We compared the effect of supplementing isoflurane/N2O/O2 anesthesia with an opioid agonist (fentanyl [n = 15]) or two drugs inhibiting the NMDA system differently (magnesium, ketamine [n = 15 in each group]) on sensory changes after abdominal hysterectomy. Electric sensation, pain detection, and pain tolerance thresholds were determined (preoperatively and 1, 4, 24 h, and 5 days postoperatively) in arm, thoracic, incision, and leg dermatomes together with pain scores and cumulative morphine consumption. Thresholds relative to the arm were derived to unmask segmental sensory changes hidden by generalized changes. Absolute thresholds were increased 1-24 h, returning to baseline on Day 5, without overall differences among drugs. Fentanyl thresholds were lower 1 h and higher 5 days postoperatively compared with magnesium and ketamine; thresholds were lower at 24 h for magnesium versus ketamine. Relative thresholds increased compared with baseline only with fentanyl (1-4 h); none decreased. Pain scores and morphine consumption were similar. Thus, all adjuvants suppressed spinal sensitization after surgery. Fentanyl showed the most, and magnesium the least, central sensory inhibition up to 5 days postoperatively, with different patterns of inhibition directly postsurgery versus later. Differences in sensory processing were not reflected in clinical measures. IMPLICATIONS: We studied the effects on postsurgical sensory processing of general anesthesia supplemented by drugs affecting opioid or N-methyl-D-aspartate receptors using sensory thresholds. Generalized central sensory inhibition, differently affected by the drugs, predominated after surgery. All drugs suppressed spinal excitation. Clinical pain measures did not reflect sensory change.

Low incidence of the oculocardiac reflex and postoperative nausea and vomiting in adults undergoing strabismus surgery.

PURPOSE: To investigate the incidence of the oculocardiac reflex (OCR), and of postoperative nausea and vomiting (PONV) in adults undergoing strabismus surgery. METHODS: Adults (18-86 yr) undergoing inpatient strabismus surgery received 10 micrograms.kg-1 atropine and 10 micrograms.kg-1 altentanil iv and were randomly allocated to: (A) 5 mg.kg-1 thiopentone iv, isoflurane/N2O maintenance; (B) 3 mg.kg-1 propofol iv, propofol/N2O maintenance (10-14 mg.kg-1.hr-1); 3 mg.kg-1 propofol iv, propofol/air/O2 maintenance (10-14 mg.kg-1.hr-1). Analyses were with the number-needed-to-treat/harm. RESULTS: In 97 adults the absolute risk of OCR (13-20%) and PONV (21-31% after 24 hr) was low, with no differences between groups. Number-needed-to-treat to prevent PONV with propofol with or without N2O compared with thiopentone-isoflurane was 7 to 11. Number-needed-to-harm for one OCR with propofol compared with thiopentone-isoflurane was 17. CONCLUSION: Adults undergoing strabismus surgery with prophylactic atropine had a low risk of OCR and PONV, independent of the anaesthetic technique used.

Role of magnesium sulfate in postoperative analgesia.

BACKGROUND: N-methyl-D-aspartate antagonists may play a role in the prevention of pain. An assessment was made of the effect of the physiologic N-methyl-D-aspartate antagonist magnesium on analgesic requirements, pain, comfort, and quality of sleep in the postoperative period. METHODS: In a randomized, double-blind study, 42 patients undergoing elective abdominal hysterectomy with general anesthesia received 20% magnesium sulfate or saline (control) 15 ml intravenously before start of surgery and 2.5 ml/h for the next 20 h. Postoperative morphine requirement was assessed for 48 h using patient-controlled analgesia. Maximum expiratory flow (peak flow), pain at rest and during peak flow, and discomfort were evaluated up to the 48th postoperative hour, and 1 week and 1 month after surgery. Insomnia was evaluated after the first and second postoperative nights. RESULTS: Compared to control subjects, magnesium-treated patients consumed less morphine during the first 48h (P<0.03), which was most pronounced during the first 6 h (P<0.004), and experienced less discomfort during the first and second postoperative days (P<0.05-0.005). The magnesium-treated group revealed no change in postoperative sleeping patterns when compared to preoperative patterns. Control patients showed an increase in insomnia during the first and second postoperative nights (P<0.002 and P<0.005, respectively) compared to preoperative values. CONCLUSIONS: This is the first clinical study showing that the perioperative application of magnesium sulfate is associated with smaller analgesic requirement, less discomfort, and a better quality of sleep in the postoperative period but not with adverse effects. Magnesium could be of interest as an adjuvant to postoperative analgesia.

Alkalinization of lidocaine 2% does not influence the quality of epidural anaesthesia for elective caesarean section.

This double-blind randomized study compared the effects of an epidural injection of lidocaine hydrochloride 2% (HCl) (Group 1), alkalinized lidocaine 2% (1 ml NaHCO3 per 10 ml of solution) injected either immediately (Group 2) or one hour after preparation (Group 3) in 45 parturients (n = 15 per group) scheduled for elective Caesarean section. Each patient received 16 ml of one of the three solutions. The mean pH values measured just before administration with a pH-meter PHM 64 Metrohm AG were 6.77 for the HCl lidocaine 2% solution, 7.34 for the freshly alkalinized solution and 7.35 for the solution prepared one hour before injection. The median maximal sensory level (range) observed was T3 (T8-C7), T4 (T5-C8) and T4 (T6-C6), obtained after 19 +/- 6 min, 18 +/- 8 min and 16 +/- 6 min respectively for each group. A motor block of grade 2 or 3 on the Bromage scale was obtained in 11, 10 and 14 patients respectively. No failure was observed although 3, 5, and 2 patients in Groups 1, 2, and 3 respectively required a supplementary bolus 20 min after the initial injection because of inadequate sensory level or pain at the operative site. In conclusion, this study shows that neither fresh alkalinization of 2% lidocaine nor the delay of one hour between preparation and injection of the alkalinized solution influences the onset or quality of epidural anaesthesia for elective Caesarean section.

Successful term pregnancy after Mustard operation for transposition of the great arteries.

Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.

Epidural-morphine-induced pruritus: propofol versus naloxone.

In a prospective, randomized, double-blind clinical trial, we compared the efficacy of propofol and naloxone for the treatment of spinal-morphine-induced pruritus. Forty patients presenting with severe pruritus within 24 h of epidural morphine administration were allocated to receive either propofol 10 mg intravenously (i.v.) or naloxone 2 micrograms/kg. In the absence of a positive response, a second dose of the same treatment was given 5 min later. Pruritus and the level of post-operative pain were assessed every 5 min up to the end of the study period (45 min) using a verbal rating scale. The overall success rate in treating pruritus was similar in the two groups (80%). The rate of success after the first injection of the treatment drug was also similar (55%). The level of postoperative pain decreased after drug treatment in six patients (30%) in the propofol group versus none in the naloxone group (P < 0.05). Forty-five percent of the patients in the naloxone group had an increase in the level of postoperative pain versus none in the propofol group (P < 0.05). In conclusion, these results suggest that propofol and naloxone are equally effective in treating spinal-morphine-induced pruritus. However, the level of postoperative pain is significantly less in the propofol group.

Comparison of extradural administration of sufentanil, morphine and sufentanil-morphine combination after caesarean section.

We have studied postoperative analgesia and unwanted side effects of a single dose of a mixture of morphine and sufentanil administered extradurally with the effects produced by extradural injection of each opioid alone in 64 patients after Caesarean delivery. The patients were allocated randomly to receive morphine 4 mg (n = 21), sufentanil 50 micrograms (n = 22) or morphine 2 mg with sufentanil 25 micrograms (n = 21) via an extradural catheter in a double-blind design. Intensity of pain was measured using a linear visual analogue scale. Compared with the effect produced by morphine alone, the morphine-sufentanil combination produced more rapid onset of pain relief (19 (SD 5) min vs 79 (23) min for a 75% reduction of pain; P less than 0.01), whereas the duration and quality of analgesia assessed during 12 h was similar for these two groups. In contrast, patients receiving sufentanil alone required significantly more supplementary analgesia 4 h after administration than with morphine alone or morphine combined with sufentanil. There were no significant changes in cardiorespiratory variables in any group. Side effects consisted mainly of pruritus and nausea and did not differ between groups, with the exception of early and transient dizziness which was observed only in patients given sufentanil either alone or in combination with morphine. We conclude that a single extradural injection of morphine and sufentanil combines the short onset time produced by sufentanil and the long duration of analgesia attributable to morphine, thus providing excellent and prolonged analgesia after Caesarean delivery.

Subhypnotic doses of propofol relieve pruritus induced by epidural and intrathecal morphine.

We investigated the efficacy of subhypnotic doses of propofol for spinal morphine-induced pruritus in a prospective, randomized, double-blind, placebo-controlled study. Fifty patients, ASA physical status 1-3, with spinal morphine-induced pruritus were allocated to receive either 1 ml propofol (10 mg) or 1 ml placebo (Intralipid) intravenously after gynecologic, orthopedic, thoracic, or gastrointestinal surgery. In the absence of a positive response, a second drug treatment was given 5 min later. The persistence of pruritus 5 min after the second treatment dose was considered a treatment failure. All failures then received, in an open fashion, a supplementary dose of propofol (10 mg) and were reevaluated 5 min later. Both groups were well matched. The success rate was significantly greater in the propofol group (84%) than in the placebo (16%) group (P less than 0.05). Ninety percent of the treatment failures in the placebo group were successfully treated by a supplementary dose of 10 mg propofol. Eight percent of the patients (4% in each group) were resistant to all treatments, including naloxone 0.08 mg intravenously. Three patients had a slight increase in sedation in the propofol group versus none in control (not significant). The beneficial effect of treatment was longer than 60 min in 85% of patients in the propofol group and in 100% of the controls (not significant). These results suggest that propofol in a subhypnotic dose is an efficient drug treatment for spinal morphine-induced pruritus. At the dose administered (10 mg), side effects were rare and minor.

Subhypnotic doses of propofol possess direct antiemetic properties.

Propofol is associated with a low incidence of postoperative nausea and vomiting. In a prospective, randomized, double-blind, placebo-controlled study, we investigated the possible direct antiemetic properties of a subhypnotic dose of propofol. Fifty-two ASA physical status I or II patients, aged 15-60 yr with nausea and vomiting after minor gynecologic, orthopedic, or digestive tract surgery, were included in the study and received either propofol (10 mg = 1 mL) or placebo (1 mL Intralipid) intravenously in the postanesthesia care unit. Patients treated with propofol experienced a larger reduction in nausea and vomiting than patients treated with placebo (81% vs 35% success rate; P less than 0.05). Patients successfully treated had a similar incidence of relapse (propofol 28%; placebo 22%) within the first 30 min after therapy. Thirty-three percent of the propofol-treated patients and 44% of the placebo-treated patients showed a minor increase in sedation. The level of postoperative pain did not change in either group. Hemodynamic values remained unchanged in both groups. Pain on injection (7.6%) or dizziness (3.6%) only occurred in the propofol group. We conclude that propofol has significant direct antiemetic properties.

Peripartum cardiomyopathy: a case report.

Peripartum cardiomyopathy is characterized by congestive left ventricular failure appearing during the last trimester of pregnancy or during the 6 months following delivery, without any specific etiology or pre-existing cardiac disease. The present report describes the case history of a woman presenting with severe cardiac failure immediately after the delivery of twins.

[Accumulation of carbon dioxide in the operative field in ophthalmic interventions under local anesthesia]. / L'accumulation de CO2 sous le champ opératoire des interventions ophtalmologiques en anesthésie locale.

In eye surgery under local anaesthesia, a micro-climate develops under the operative field. Respiratory CO2 concentration, measured by an infrared capnograph, increases rapidly and becomes stable at a certain level. A three-dimensional relation has been established (CO2 concentration X weight of the patient X free space under the field). The effects of the accumulated CO2 are complex and partially depending on premedication. The air inhaled by the patient should be renewed by elimination of the excess CO2.

[Per- and postoperative buprenorphine analgesia: cardiocirculatory and respiratory effects]. / L'analgésie per et postopératoire à la buprénorphine: effets cardio-circulatoires et respiratoires.

In 25 non-premedicated patients, buprénorphine (5 micrograms/kg - 1) has been injected i.v. 30 mn before coelioscopic sterilization under general anaesthesia. Following the i.v. injection there no significant modification of the arterial systolic and diastolic blood pressure was observed but post-operative bradycardia. Tidal volume and minute/ventilation decreased whereas the respiratory rate remained stable. Arterial blood gaz analysis showed slightly hypoxaemia and a significant rise of PaCO2 with post-operative acidosis similar to that in the control group. Good postoperative analgesia was achieved but with profound sedation and a high incidence of nausea and vomiting.

[Comparative study of sequential analgesic anesthesia (SAA) with continuous-infusion analgesia by fentanyl]. / Etude comparative de l'anesthésie analgésique séquentielle (AAS) avec l'analgésie en perfusion continue au fentanyl.

A group of elderly (mean age: 75 years) patients undergoing a prothetic on the hip under analgesic anaesthesia using fentanyl by continuous infusion (7 micrograms.kg.h(-1)) was compared with a similar group receiving sequential analgesic anaesthesia using fentanyl (25 micrograms.kg as a bolus then 7 micrograms.kg(-1).2030mins(-1)). Comparison of the results obtained revealed a variation in mean cardiocirculatory parameters which was less marked in the group receiving fentanyl by infusion than in the group receiving it sequentially. The higher doses used in the sequential analgesia group led in the majority of cases to severe respiratory depression requiring its reversal by an antagonist or postoperative ventilatory assistance, whilst the use of fentanyl by infusion made it possible to reduce total doses of the drug and ensure adequate spontaneous respiration at the end of the operation.