Sevoflurane analgesia in labour (Sevo'n'ox).
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Analgesia, Obstetrical↗
Biomedical subjects
J H McClure
Publications and source records attributed to J H McClure.
Maternal deaths from anaesthesia. An extract from Why Mothers Die 2000-2002, the Confidential Enquiries into Maternal Deaths in the United Kingdom: Chapter 9: Anaesthesia.
This is the first of two extracts from Why Mothers Die 2000-2002, issued on 12 November 2004 by the Confidential enquiry into Maternal and Child Health (CEMACH), reproduced with permission. The full report can be accessed via their web site: http://www.cemach.org.uk/
Anesthesia↗
Quantitative assessment of motor block in labouring women receiving epidural analgesia.
The assessment of motor block associated with epidural analgesia is traditionally performed using the modified Bromage Score. However, it is a qualitative and quantitative measurement of both spread and intensity of motor block in the lower limbs, and it has been adapted from Bromage's original use as an assessment of the adequacy of epidural anaesthesia for abdominal surgery. A number of quantitative assessment methods exist but these are either laboratory based and/or impracticable in the clinical situation of labour. We therefore set out to devise a quantitative assessment method which would be easy to use and acceptable to labouring women receiving epidural analgesia. A force transducer was modified to enable power of hip adduction to be assessed quantitatively before and after epidural analgesia was established. These results were compared with the modified Bromage Scale and an extended scale which further subdivided the scores between 0 and 1. Our results show that there is a large variation in the quantitative measurement of motor block (as measured by adductor strength) that may not be detected by the sole use of the modified Bromage Score. We suggest that future studies to assess motor block in the clinical setting use an additional quantitative method of assessment.
Analgesia, Epidural↗
Haemodynamic effects of diaspirin crosslinked haemoglobin (DCLHb) given before abdominal aortic aneurysm surgery.
We studied 34 patients undergoing elective repair of an abdominal aortic aneurysm under combined general anaesthesia and epidural block to evaluate the acute effects of diaspirin crosslinked haemoglobin (DCLHb) 50, 100 and 200 mg kg-1 i.v. Haemodynamic variables were measured continuously using pulmonary and radial artery catheters, and oxygen delivery and consumption were calculated at regular intervals. DCLHb was shown to be vasoactive, producing an increase in mean arterial pressure of approximately 25% with each dose, with small decreases in cardiac index and calculated oxygen delivery. These effects persisted beyond the end of infusion and provided a degree of cardiovascular stability during the operative procedure. The effects of DCLHb on oxygen consumption at these doses were minimal.
Aged↗
Ropivacaine 0.75% for extradural anaesthesia in elective caesarean section: an open clinical and pharmacokinetic study in mother and neonate.
In an open study we have investigated the efficacy of 20 ml of 0.75% ropivacaine (7.5 mg ml-1) to provide extradural anaesthesia for elective Caesarean section. Plasma concentrations (total and free) were estimated in the mother and neonate. Anaesthesia was effective and safe. Plasma concentrations of ropivacaine in the mother and neonate were within safe limits and consistent with previous studies. Two mothers received accidental i.v. injections of ropivacaine 75 mg and 150 mg, respectively, without serious adverse effects.
Adult↗
Comparison of single, end-holed and multi-orifice extradural catheters when used for continuous infusion of local anaesthetic during labour.
Single, end-holed and multi-orifice extradural catheters were compared in terms of efficacy and complications when used for infusion of 0.1% bupivacaine during labour. In this study of 364 patients there was no difference in unilateral block after an initial bolus dose (18 (11.5%) for single, end-holed and 16 (10.9%) for multi-orifice catheters). Unilateral block recurred with seven (4.0%) single, end-holed and with eight (4.8%) multi-orifice catheters. Unilateral blocks, arising for the first time during infusion of local anaesthetic, occurred significantly more frequently when single, end-holed catheters were used (29 (16.4%)) compared with multi-orifice catheters (14 (8.4%)) (P < 0.05).
Analgesia, Epidural↗
Pharmacokinetic and clinical study of ropivacaine and bupivacaine in women receiving extradural analgesia in labour.
We have compared, in a randomized, double-blind study, the pharmacokinetics of ropivacaine and bupivacaine during labour. Total and free plasma concentrations of ropivacaine and bupivacaine were measured after the first of two extradural doses. The main dose was 20 mg (test dose) and 30 mg, with a top-up dose of 25 mg when requested. After the main dose, Cpmax (total) of ropivacaine (0.50 mg litre-1) was similar to that of bupivacaine (0.48 mg litre-1). At 20 min, Cpmax (free) of ropivacaine (0.04 mg litre-1) was higher than that of bupivacaine (0.02 mg litre-1) (P = 0.0025). The clinical effectiveness of the block was similar in both groups.
Amides↗
A comparison of non-invasive methods of blood pressure measurement in normotensive and hypertensive pregnant women.
We compared two types of automatic non-invasive blood pressure measuring device with sphygmomanometey in 47 normotensive and 38 hypertensive women in the third trimester of pregnancy. An automatic oscillometric device (Accutor) and a volume-clamp device (Finapres) significantly underestimated the diastolic pressure as measured by the fourth Korotkoff sound using a Hawksley random zero sphygmomanometer. The mean difference between the sphygmomanometer and Accutor measurement of diastolic blood pressure was +3.1 mmHg in the normotensive women and +8.3 mmHg in the hypertensive women (P = 0.001). The mean difference between the sphygmomanometer and Finapres measurement of diastolic blood pressure was +6.1 mmHg in the normotensive women and +11.5 mmHg in hypertensive women (P = 0.003). The increased use of continuous non-invasive devices to monitor blood pressure in women with hypertension should be accompanied by sound knowledge of their limitations in this group of patients.
Journal Article↗
Arnold-chiari malformation in pregnancy.
We report the case of a 30-year-old pregnant woman with an Arnold-Chiari malformation, who presented with severe pregnancy-induced hypertension at 30 weeks gestation. She was known to have had a difficult tracheal intubation during a previous general anaesthetic. Caesarean section was performed under an incremental epidural anaesthetic block.
Adult↗
Backache and epidural analgesia: a retrospective survey of mothers 1 year after childbirth.
A questionnaire was sent to 2065 mothers 1 year after delivery as part of a larger study into patient satisfaction with all aspects of their obstetric care. The response rate adjusted for non-delivered mail was 67.1%. There was a high incidence of new long-term backache in mothers who had received epidural analgesia (26.2% at one year) compared to the mothers who had not (1.7%). Further analysis of the data revealed no other significant associated factor.
Journal Article↗
Comparison of ropivacaine and bupivacaine in extradural analgesia for the relief of pain in labour.
Forty women having requested extradural analgesia for labour were allocated randomly to receive 0.5% ropivacaine or bupivacaine 10 ml as the main dose. When a top-up was requested, 0.25% ropivacaine or bupivacaine 10 ml was given (the same drug as the main dose). The study ended when a second top-up was requested or delivery of the baby occurred. Pain from two contractions was assessed before extradural block by visual analogue scoring and thereafter with every contraction. Sensory block and motor block were assessed at intervals. The only significant difference between the groups was a shorter onset of pain relief after the main dose of bupivacaine; there were no other significant differences in duration, onset of pain relief after top-up, quality of analgesia, spread of sensory block and motor block between the groups. Cardiovascular changes and neonatal outcome were similar in the two groups.
Adolescent↗
Acute colonic pseudo-obstruction after caesarean section.
A 32-year-old patient developed pseudo-obstruction of the large bowel following elective caesarean section. The association of this rare postoperative complication with anaesthesia is discussed. Pseudo-obstruction of the large bowel (Ogilvie's Syndrome), is characterised by an adynamic mechanically unobstructed bowel which may progress to marked dilatation of the caecum. The reported mortality varies from 14-30% rising to 40-50% if there is caecal perforation. The underlying mechanism is thought to be an imbalance of the autonomic nervous system.
Journal Article↗
Efficacy and kinetics of extradural ropivacaine: comparison with bupivacaine.
Ninety-one patients were allocated randomly to three groups to receive 1% ropivacaine 10 ml, 0.5% ropivacaine 20 ml or 0.5% bupivacaine 20 ml extradurally. Intermittent sensory (pinprick) and motor (Bromage scale) assessments of the block produced were recorded, with an assessment of the quality of the block and the requirement for supplementary analgesia. There was little difference between the groups in frequency, onset, duration or spread of sensory block. However, the motor block produced by 0.5% ropivacaine was less intense and of shorter duration than that with bupivacaine. The block produced by the smaller volume of ropivacaine was less reliable clinically than the larger, more dilute, solution and more anaesthetic supplements were required in that group. Cardiovascular changes were similar in all three groups. The peak plasma concentration of ropivacaine was significantly greater and T1/2 significantly shorter than those of bupivacaine, although no patient showed any features of systemic toxicity. The systemic kinetics of ropivacaine were not influenced significantly by varying the concentration or volume administered.
Adult↗
Respiratory depression after extradural fentanyl.
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Anesthesia, Epidural↗
Factors influencing the hyperaemic response after carotid endarterectomy.
Transcranial Doppler ultrasonography was used to evaluate serially the changes in middle cerebral artery blood flow velocity (MCAV) in 37 consecutive patients during the first 72 h after carotid endarterectomy to identify factors that may predispose towards postoperative hyperaemia. Within 6 h of endarterectomy, median MCAV in the operated hemisphere was 48 per cent (95 per cent confidence interval 37-60 per cent) above that on admission and remained 27 per cent (95 per cent confidence interval 19-37 per cent) higher at 72 h. There was a similar, but less marked, increase in MCAV in the contralateral middle cerebral artery during the same time period. There was no association between the postoperative increase in MCAV and clinical presentation, admission MCAV, the presence or absence of a residual neurological deficit or infarction on computed tomography before operation, carotid clamp time, shunt usage, internal carotid artery stump pressure or MCAV during clamping. The greatest increase in MCAV was observed in patients with internal carotid artery stenosis > or = 50 per cent and, more particularly, in those with preoperative evidence of impaired cerebrovascular reserve. In the latter patients, MCAV was 100 per cent above the admission level within 12 h of operation and was still 50 per cent raised at 72 h.
Blood Flow Velocity↗
Immediate effects of carotid clamp release on middle cerebral artery blood flow velocity during carotid endarterectomy.
Transcranial Doppler ultrasound was employed in 44 patients undergoing carotid endarterectomy in order to identify factors associated with the greatest increases in middle cerebral artery blood flow velocity (MCAV) immediately after carotid clamp release and restoration of flow. Previous reports have suggested that such increases might reflect post-ischemic hyperaemia. Overall, the median increase in MCAV on restoration of flow [58 cm/s (95% Cl 44-68)] was greater than the median decrease in MCAV after initial carotid clamping [36 cm/s (95% Cl 26-43), p < 0.0001]. However, the immediate increase in MCAV tended to be transient and, in one patient, may have represented a hyperaemic response to a haemodynamically induced intraoperative neurological deficit. There was no association between the magnitude of MCAV increase and clinical presentation, degree of carotid stenosis, computed tomography scan findings, type of anaesthesia, nor the presence or absence of impaired cerebral vascular reserve, nor the occurrence of intraoperative air embolisation. The greatest increases in MCAV on clamp release were observed in patients with the greatest decreases in MCAV at clamping and those with the lowest internal carotid artery stump pressures. The most likely explanation for the findings is that they represent a transient hyperaemic response to carotid occlusion. It remains unclear whether this phenomenon is mediated by some degree of ischaemic injury or simply by the effect of a sudden surge of blood through low resistance arterioles that have dilated in order to maintain the collateral circulation during carotid clamping.
Blood Flow Velocity↗