Biomedical subjects

S W Simmons

Publications and source records attributed to S W Simmons.

13 recordsLinked to original sources

PubMed2006

Techniques for preventing hypotension during spinal anaesthesia for caesarean section.

BACKGROUND: Maternal hypotension, the most frequent complication of spinal anaesthesia for caesarean section, can be associated with severe nausea or vomiting which can pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis and neurological injury). OBJECTIVES: To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (November 2005). SELECTION CRITERIA: Randomised controlled trials comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed eligibility and methodological quality of studies, and extracted data. MAIN RESULTS: We included 75 trials (a total of 4624 women). Crystalloids were more effective than no fluids (relative risk (RR) 0.78, 95% confidence interval (CI) 0.60 to 1.00; one trial, 140 women, sequential analysis) and colloids were more effective than crystalloids (RR 0.68, 95% CI 0.52 to 0.89; 11 trials, 698 women) in preventing hypotension following spinal anaesthesia at caesarean section. No differences were detected for different doses, rates or methods of administering colloids or crystalloids. Ephedrine was significantly more effective than control (RR 0.51, 95% CI 0.33 to 0.78; seven trials, 470 women) or crystalloid (RR 0.70, 95% CI 0.50 to 0.96; four trials, 293 women) in preventing hypotension. No significant differences in hypotension were seen between ephedrine and phenylephrine (RR 0.95, 95% CI 0.37 to 2.44; three trials, 97 women) and phenylephrine was more effective than controls (RR 0.27, 95% CI 0.16 to 0.45; two trials, 110 women). High rates or doses of ephedrine may increase hypertension and tachycardia incidence. Lower limb compression was more effective than control (no leg compression) (RR 0.69, 95% CI 0.53 to 0.90; seven trials, 399 women) in preventing hypotension, although different methods of compression appeared to vary in their effectiveness. No other comparisons between different physical methods such as position were shown to be effective, but these trials were often small and thus underpowered to detect true effects should they exist. AUTHORS' CONCLUSIONS: While interventions such as colloids, ephedrine, phenylephrine or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension during spinal anaesthesia for caesarean section. No conclusions can be drawn regarding rare adverse effects due to the relatively small numbers of women studied.

Anesthesia, Obstetrical↗

PubMed2003

Combined spinal-epidural versus epidural analgesia in labour.

BACKGROUND: Traditional epidural techniques have been associated with prolonged labour, use of oxytocin augmentation, and increased incidence of instrumental vaginal delivery. The combined spinal-epidural (CSE) technique has been introduced in an attempt to reduce these adverse effects. CSE is believed to improve maternal mobility during labour and provide more rapid onset of analgesia than epidural analgesia. OBJECTIVES: To assess the relative effects of combined spinal-epidural versus epidural analgesia during labour. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group Trials Register (July 2002), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002), MEDLINE (1966 to June 2002) and EMBASE (1974 to June 2002). SELECTION CRITERIA: All published randomised controlled trials involving a comparison of CSE with epidural analgesia initiated for women in the first stage of labour. DATA COLLECTION AND ANALYSIS: Trials identified from searching were assessed for inclusion by the same two reviewers independently. Review Manager software was used for calculation of the treatment effect represented by odds ratios (OR) and weighted mean difference (WMD) using a fixed effects model with 95% confidence intervals (CI). MAIN RESULTS: Fourteen trials (2047 women) met our inclusion criteria. Of the 25 outcomes analysed from these studies CSE shows a reduced time from first injection to effective maternal analgesia WMD -5.50 minutes (95% CI -6.47 to -4.52; four trials), an increased incidence of maternal satisfaction OR 4.69 (95% CI 1.27 to 17.29; three trials), and an increased incidence of pruritus OR 2.79 (95% CI 1.87 to 4.18; nine trials). No difference was found between CSE and epidural techniques with regards to maternal mobility, rescue analgesia requirements, the incidence of post dural puncture headache (PDPH) or blood patch, hypotension, urinary retention, mode of delivery, or admission of the baby to the neonatal unit. REVIEWER'S CONCLUSIONS: There is no standard CSE or epidural technique. Compared with epidural, CSE provides faster onset of effective pain relief from the time of injection, and increases the incidence of maternal satisfaction. However, CSE women experience more itch. There is no difference between CSE and epidural techniques with respect to: the incidence of forceps delivery, maternal mobility, PDPH, caesarean section rates or admission of babies to the neonatal unit. It is not possible to draw any meaningful conclusions regarding rare complications such as nerve injury and meningitis.

Analgesia, Epidural↗

PubMed2003

Avoiding inadvertent epidural injection of drugs intended for non-epidural use.

Inadvertent administration of non-epidural medications into the epidural space has the potential for serious morbidity and mortality. The aim of this study was to collate reported incidents of this type, describe the potential mechanisms of occurrence and identify possible solutions. We searched medical databases and reviewed reference lists of papers retrieved, covering a period of 35 years, regarding this type of medication incident. The 31 reports of 37 cases found is likely to represent a gross underestimation of the actual number of incidents that occur. "Syringe swap", "ampoule error", and epidural/intravenous line confusion were the main sources of error in 36/37 cases (97%). Given that no effective treatment for such errors has been identified, prevention should be the main defence strategy. Despite all the precautions that are currently undertaken, accidents will inevitably occur. We have identified areas for systemwide change that may prevent these types of incidents from occurring in future.

Drug Labeling↗

PubMed2002

Aseptic precautions for inserting an epidural catheter: a survey of obstetric anaesthetists.

We performed a postal survey of Fellows of the Australian and New Zealand College of Anaesthetists with a special interest in obstetric practice, about their beliefs regarding aseptic precautions for insertion of an epidural catheter in the labour ward. Of the 435 consultant anaesthetists surveyed, 367 responded (84%), revealing a wide variation in practice. It was not thought to be essential practice to remove a watch before washing hands by 51 respondents (14%), to wear a facemask by 105 (29%) or to wear a sterile gown by 45 (12%). Three anaesthetists (1%) did not believe sterile gloves were essential. However, all respondents indicated that an antiseptic skin preparation was essential. Our results raise questions regarding an acceptable standard of aseptic practice for the insertion of an epidural catheter in labour and we propose a minimal standard of essential precautions.

Anesthesia, Epidural↗

PubMed2001

Techniques for preventing hypotension during spinal anaesthesia for caesarean section.

BACKGROUND: Maternal hypotension is the most frequent complication of a spinal anaesthetic for caesarean section with an incidence approaching 100%. Most workers define hypotension as a maternal systolic blood pressure below 70-80% of baseline recordings and/or an absolute value of < 90 -100mmHg. The frequent occurrence and rapid onset of hypotension during spinal anaesthesia has encouraged anaesthetists to try and prevent or minimise the associated maternal symptoms of nausea and vomiting during the establishment of the block. Untreated, severe hypotension can also pose serious risks to both mother (unconsciousness, pulmonary aspiration, apnoea or even cardiac arrest) and baby (impaired placental perfusion leading to hypoxia, fetal acidosis and neurological injury). A range of strategies is currently used to prevent or minimise hypotension but there is no established ideal technique. OBJECTIVES: To assess the relative efficacy and side effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group Trials Register, the Cochrane Controlled Trials Register, other databases and bibliographies of relevant papers are searched according to the strategy developed for the Pregnancy and Childbirth Group as a whole. Date of last search: May 2001. SELECTION CRITERIA: All published or unpublished randomised controlled trials that compare use of an intervention to prevent hypotension with placebo or alternative treatment in patients having spinal anaesthesia for caesarean section. DATA COLLECTION AND ANALYSIS: Trials identified from searching are assessed for inclusion by the same two reviewers independently. Studies are excluded from review for the following reasons: hypotension is not an outcome measure or clearly defined prior to administering a rescue treatment; randomisation is unsatisfactory; the spinal anaesthetic technique or dose of local anaesthetic is not controlled-for; and the intervention is implemented in response to a fall in blood pressure rather than for prevention. Statistical analyses use the Review Manager software for calculation of the treatment effect as represented by the relative risks and proportional and absolute risk reductions. MAIN RESULTS: Twenty trials meet the criteria for inclusion. Four of the twelve interventions reviewed are shown to reduce the incidence of hypotension under spinal anaesthesia for caesarean section: (1) crystalloid 20ml/kg vs control, Relative Risk (RR) 0.78 (95% confidence interval (CI) 0.6, 1.0); (2) pre-emptive colloid administration vs crystalloid, (RR) 0.54 (95% CI 0.37, 0.78); (3) ephedrine vs control, RR 0.70 (95% CI 0.57, 0.85); and (4) lower limb compression vs control, RR 0.75 (95% CI 0.59, 0.94). There are no significant differences in maternal or neonatal side effects in any of the comparisons studied. REVIEWER'S CONCLUSIONS: No studied intervention has been shown to eliminate the need to treat maternal hypotension during spinal anaesthesia for caesarean section. We are unable to draw any conclusions regarding adverse effects of the studied interventions, due to their probable low incidence and the small number of women studied. Further randomised controlled trials are recommended, in particular assessing a combination of the beneficial interventions, i.e. colloid or crystalloid preloading, parenteral ephedrine administration and leg compression with bandages, stockings or inflatable boots.

Anesthesia, Obstetrical↗

PubMed1999

A survey of Australasian obstetric anaesthesia audit.

In order to develop a minimal obstetric anaesthesia dataset based on current Australasian clinical audit best practice, we carried out a postal survey of 69 Australasian anaesthetic departments covering an obstetric service. We asked about data being collected, specifically concerning the high risk obstetric patient, epidural analgesia and postoperative anaesthetic review. Examples of any data collection forms were requested. Of the 66 responses, 35 departments (53%) were not collecting any audit data. Twenty-six of the 31 departments (84%) performing obstetric anaesthesia audit responded to our follow-up telephone survey. Eighteen departments believed that there had been an improvement in patient care as a result of their audit and 13 felt that the benefits outweighed the costs involved. However, only six departments (9%) had performed an audit cycle. The importance of feedback to patients or hospital staff and the incidence of post dural puncture headache (PDPH) were cited by some as priorities for obstetric anaesthesia audit. There was however no consistency as to what data should be collected. Many responses suggested a perceived need to collect clinical data without knowing what to do with it. Our survey has highlighted confusion between three distinct objectives; a dataset for obstetric anaesthesia record keeping, data required for continuing patient management in hospital and, a specific minimal dataset for clinical audit purposes. We conclude that current Australasian obstetric anaesthesia audit strategies are inadequate to develop a minimal dataset for cost-effective clinical audit.

Analgesia, Epidural↗

PubMed1994