British journal of anaesthesia
-
Clinical Trial Controlled Clinical Trial
Extradural pain relief in labour: bupivacaine sparing by extradural fentanyl is dose dependent.
The minimum local analgesic concentration (MLAC) of bupivacaine in labour is defined as the effective concentration in 50% of subjects (EC50). We have used the technique of double-blinded sequential allocation to quantify the bupivacaine sparing effect of the addition of four different doses of extradural fentanyl in 223 labouring women. There were five groups: (1) plain bupivacaine (control); (2) bupivacaine with fentanyl 1 microgram ml-1; (3) bupivacaine with fentanyl 2 micrograms ml-1; (4) bupivacaine with fentanyl 3 micrograms ml-1; and (5) bupivacaine with fentanyl 4 micrograms ml-1. ⋯ We observed a reduction in MLAC of 18%, 31% (P = 0.03%), 55% (P < 0.0001) and 72% (P < 0.0001) with fentanyl 1, 2, 3 and 4 micrograms ml-1, respectively, demonstrating a significant negative linear trend (P < 0.0001) with increasing fentanyl dose. The incidence of pruritus was increased significantly with fentanyl 4 micrograms ml-1 (P = 0.0015). Because of this, fentanyl 3 micrograms ml-1 may be the optimal dose when the aim is bupivacaine sparing extradural analgesia during labour.
-
Clinical Trial
Assessment of cardiovascular changes during laparoscopic hernia repair using oesophageal Doppler.
We have used an oesophageal Doppler to measure aortic blood flow velocity before, during and after induction of carbon dioxide pneumoperitoneum in 10 consecutive patients, mean age 58 yr, undergoing laparoscopic hernia repair. Derived values for stroke distance, minute distance and systemic vascular resistance showed considerable interpatient variation indicating unpredictable haemodynamic responses. ⋯ There was a corresponding increase in the index of systemic vascular resistance from 1092 (747) to 2079 (400) (P < 0.05) which persisted after deflation of the abdomen. Oesophageal Doppler can provide continuous online haemodynamic data with a rapid response to acute changes and may have a role in non-invasive haemodynamic monitoring during laparoscopic procedures in older patients with cardiovascular disease.
-
Clinical Trial
Can prolonged expiration manoeuvres improve the prediction of arterial PCO2 from end-tidal PCO2?
We have studied, in 16 patients undergoing thoracoabdominal oesophagectomy, if two prolonged expiration manoeuvres improve prediction of arterial PCO2 (PaCO2) from end-tidal PCO2 (PE' CO2). PE' CO2, PCO2 at the end of a simple prolonged expiration (PE1 CO2), and PCO2 at the end of a prolonged expiration preceded by sustained hyperinflation of the lungs (PE2 CO2), were measured during laparotomy, in the lateral thoracotomy position during two-lung ventilation, and after transition to one-lung ventilation. (PaCO2-PE' CO2) was 1.3 (SD 0.4) kPa during laparotomy and this remained stable throughout the study. ⋯ However, PE1 CO2 and PE2 CO2 did not agree more closely with PaCO2 than PE' CO2 at any stage of the study. We conclude that these manoeuvres did not improve estimation of PaCO2 from PE' CO2.
-
Case Reports
Conservative management of extradural abscess complicating spinal-extradural anaesthesia for caesarean section.
We report a case of lumbar extradural abscess that presented 9 days after an elective Caesarean section performed under combined spinal-extradural anaesthesia. This was successfully treated conservatively with full recovery. The clinical course included development, and then resolution, of mild paraparesis. Conservative treatment of an extradural abscess in the obstetric population has not been described previously.
-
The auditory middle latency response (AMLR) and the 40-Hz auditory steady-state response (40-Hz ASSR) are evoked potentials which possibly arise from the same generators in the primary auditory cortex. Both responses are attenuated by most general anaesthetics. Ketamine, however, has been reported to have no effect on the AMLR. ⋯ The 40-Hz ASSR and EEG revealed no consistent differences between conscious and unconscious patients. No relationship could be demonstrated between the increase in amplitude of the 40-Hz ASSR or of relative theta power (the hallmark of ketamine effect) and loss of responsiveness to commands. We conclude that ketamine, unlike other anaesthetics, increases the amplitude of the 40-Hz ASSR.