Anaesthesia
-
Cardiorespiratory changes induced by pneumoperitoneum and head-up tilt may generate alveolar ventilation to perfusion ratio changes and increased systemic vascular resistances. The reliability of end-tidal carbon dioxide tension and pulse oximetry in predicting arterial carbon dioxide partial pressure and arterial oxygen saturation may therefore be affected. The 35 ASA 1-2 patients in this study comprised 12 men and 23 women aged 48 (SD 17) years and weighing 71 (SD 14) kg. ⋯ This gradient was highly correlated with arterial carbon dioxide partial pressure (p < 0.0001), but was not correlated with elapsed time, intra-abdominal pressure or head-up tilt. Arterial oxygen saturation was always greater than 95% in all patients and the arterial oxygen saturation-pulse oximetric saturation gradient was always less than or equal to +4%. In conclusion, end-tidal carbon dioxide partial pressure and pulse oximetric saturation allow reliable monitoring of arterial carbon dioxide partial pressure and arterial oxygen saturation in the absence of pre-existing cardiopulmonary disease and/or acute peroperative disturbance.
-
The evoked motor responses to magnetic and electrical peripheral nerve stimuli were quantitatively assessed after vecuronium in 15 women undergoing gynaecological surgery. Anaesthesia was induced with thiopentone and fentanyl and maintained with intermittent doses of fentanyl and 66% nitrous oxide in oxygen. After immobilisation of both forearms in splints, the ulnar nerves were stimulated supramaximally every 10 s with a magnetic stimulator (Magstim Model 200) and an electric stimulator (Myotest) on opposite sides. ⋯ The difference in the evoked responses between the two types of stimulation was approximately 20% overall and was significant 2 min after vecuronium administration (p < 0.05). The rate of recovery of the evoked twitch responses was more rapid with magnetic than electric stimulation. It is concluded that magnetic stimulation of peripheral nerve is a useful technique for evaluating residual neuromuscular blockade.
-
Randomized Controlled Trial Clinical Trial
Patient-controlled epidural analgesia with sufentanil following caesarean section: the effect of adrenaline and clonidine admixture.
Sixty patients, scheduled for Caesarean section were randomly allocated to receive by the epidural route in a double-blind fashion one of the following patient-controlled analgesia mixtures for the relief of postoperative pain: sufentanil 2 micrograms.ml-1 in 0.9% sodium chloride, sufentanil 2 micrograms.ml-1 + adrenaline 2.5 micrograms.ml-1, or sufentanil 2 micrograms.ml-1 + clonidine 3 micrograms.ml-1. Patient-controlled analgesia settings were a basal infusion rate of 2.5 ml.h-1, an incremental dose of 2.5 ml, a lockout interval of 10 min and a 1-h limit of 10 ml. ⋯ The quality of sleep appeared to be significantly better in the sufentanil/adrenaline group despite a significantly lower degree of sedation and higher incidence of pruritus. Treatment of pruritus with naloxone did not seem to influence the quality of analgesia.
-
Near infrared spectroscopy is a relatively new technique for monitoring intracerebral oxygen saturation. Using the technique, three episodes of cerebral hypoxia were detected during elective carotid endarterectomy which were not reliably recorded by more standard monitoring of cerebral perfusion. In one case, cerebral hypoxia was related to slippage of the tracheal tube into the right main bronchus and in the other two to episodes of hypotension. Near infrared spectroscopy is a reliable indicator of peripheral cortical perfusion and provides continuous and noninvasive monitoring of intracerebral oxygen saturation.