Behavioural effects of chronic exposure to subanesthetic concentrations of halothane, sevoflurane and desflurane in rats.

BACKGROUND: A double-blind, randomized trial was conducted to determine the behavioural effects of chronic exposure to subanesthetic concentrations of halothane, sevoflurane and desflurane in rats. METHODS: Halothane, sevoflurane and desflurane group rats received 0.1%, 0.3%, and 0.6% concentrations in a flow rate of 3 L.min(-1) O(2) respectively. Control animals also received 3 L.min(-1) O(2) in another investigation room, which had the same properties as the study group rooms. Rats breathed inhaled agents or oxygen between 09:00-13:00 hr every day for 30 days. After 30 days of inhalation of subanesthetic doses of inhaled agents or oxygen, behavioural tests were applied. RESULTS: Tests of exploratory activity and curiosity (hole-board test), anxiety (elevated plus maze test) and learning and memory functions (multiple T maze test), demonstrated that chronic exposure to subanesthetic concentrations of all three anesthetics alters behavioural functions in rats. However, impairment of learning (P<0.05) and memory function (P<0.05) were greater in association with desflurane, in comparison to halothane and sevoflurane-treated rats. CONCLUSION: Chronic exposure to subanesthetic concentrations of halothane, sevoflurane and desflurane is associated with behavioural change in rats. Of the three drugs, desflurane was associated with the lowest learning and memory function test scores.

Effects of menstrual cycle on postoperative analgesic requirements, agitation, incidence of nausea and vomiting after gynecological laparoscopy.

BACKGROUND: Several studies have suggested that the menstrual cycle has an impact on postoperative nausea and vomiting (PONV). No previous study has evaluated the effect of the menstrual cycle on the incidence of postoperative agitation and analgesic/antiemetic requirements. METHODS: On the basis of the phase of the menstrual cycle [pre+/-menstrual (Pd 25-6), early follicular phase (Pd 8-12), ovulatory phase (Pd 13-15), and luteal phase (Pd 20-24)], 67 patients enrolled in this blinded, prospective study. Anesthesia was standardized. Fentanyl was given to the patients who had severe pain in the recovery room. The patients who had agitation were given midazolam. When pain intensity was >5 on the Visual Analog Scale, metamizol was administered in the Gynecology Department. A blinded anesthesiologist recorded episodes of PONV in the recovery room, and 2 and 24 h postoperatively. RESULTS: The opioid requirement and the frequency of agitation were similar in each group. Metamizol consumption was highest in the luteal phase (p < 0.05). The follicular and luteal phases were predictors for vomiting at recovery (p < 0.05 and p < 0.001, respectively). At the postoperative 2nd hour, nausea was higher in the follicular phase than in the other phases (p < 0.05) and the luteal phase was a predictor for retching (p < 0.001). At the postoperative 24th hour, nausea was the common symptom in the luteal phase (p < 0.05). The need for ondansetron was highest in the luteal phase (p < 0.01). CONCLUSIONS: In conclusion, we suggest that the scheduling of all surgical procedures according to the menstrual phase may serve to reduce the incidence of PONV and metamizol/ondansetron consumption and hospital costs.

Comparison of neonatal effects of epidural and general anesthesia for cesarean section.

We assessed the influence of anesthetic technique for cesarean section on neonatal outcome. Thirty parturient women (ASA I/II) were randomly allocated into two groups. In Group GA general anesthesia was induced with 4 mg.kg(-1) thiopental and 1.5 mg.kg(-1) succinylcholine. In group EA epidural anesthesia was performed with 20 ml 0.375% bupivacaine through L(3-4) inter-space. 1-min Apgar scores were significantly higher in group EA (p < 0.001). Neurologic and Adaptive Capacity scores at 2 and 24 h were higher in group EA (p < 0.001). In terms of blood gas values, umbilical arterial pH and pO(2) values were higher in group EA (p < 0.05 and p < 0.001, respectively). The first breast-feeding intervals were found to be shorter in group EA (p < 0.001). We conclude that in terms of better Apgar and NAC scores, acid-base status and earlier initiation of breast-feeding, the epidural anesthesia may be preferred to general anesthesia in cesarean section.

Awake tracheal intubation through the intubating laryngeal mask airway in a patient with halo traction.

PURPOSE: To report a case of awake tracheal intubation through the intubating laryngeal mask airway (ILMA) in a patient with halo traction. CLINICAL FEATURES: A 16-yr-old, 40 kg, boy with atlanto-occipital instability and halo traction was scheduled for surgery under general anesthesia. The head of the patient was fixed in a position of flexion and extension was impossible. Cranial magnetic resonance imaging revealed that pharyngeal and laryngeal axes were aligned, but that the oral axis was in an extreme divergent plane. The tongue and oropharynx were anesthetized with 10% lidocaine spray and bilateral superior laryngeal nerve blockade was performed. Under sedation, awake orotracheal intubation via ILMA was successful. Fibreoptic bronchoscopy has been recommended for awake tracheal intubation in such patients. Other techniques, such as use of the Bullard laryngoscope have been described also but awake tracheal intubation through the ILMA in patients with a halo device in situ has seldom been reported in the medical literature. CONCLUSION: Airway management of patients with cervical spine instability includes adequate preoperative evaluation of the airway and choosing the appropriate intubation technique. We suggest that the ILMA may be an adequate alternative for awake tracheal intubation in patients with an unstable cervical spine and cervical immobilization with a halo device.