A survey in the West Midlands of the United Kingdom of current practice in managing hypotension in lower segment caesarean section under spinal anaesthesia

BackgroundSpinal anaesthesia, the most common form of anaesthesia for caesarean section, leads to sympathetic blockade and profound maternal hypotension resulting in adverse maternal and neonatal outcomes. Hypotension, nausea and vomiting remain common but until the publication of the National Institute of Health and Care Excellence (NICE) 2021 guidance, no national guideline existed on how best to manage maternal hypotension following spinal anaesthesia for caesarean section. A 2017 international consensus statement recommended prophylactic vasopressor administration to maintain a systolic blood pressure of >90% of an accurate pre-spinal value, and to avoid a drop to <80% of this value.This survey aimed to assess regional adherence to these recommendations, the presence of local guidelines for management of hypotension during caesarean section under spinal anaesthesia, and the individual clinician’s treatment thresholds for maternal hypotension and tachycardia.MethodsThe West Midlands Trainee-led Research in Anaesthesia and Intensive Care Network co-ordinated surveys of obstetric anaesthetic departments and consultant obstetric anaesthetists across 11 National Health Service Trusts in the Midlands, England.ResultsOne-hundred-and-two consultant obstetric anaesthetists returned the survey and 73% of sites had a policy for vasopressor use; 91% used phenylephrine as the first-line drug but a wide range of recommended delivery methods was noted and target blood pressure was only listed in 50% of policies. Significant variation existed in both vasopressor delivery methods and target blood pressures.ConclusionsAlthough NICE has since recommended prophylactic phenylephrine infusion and a target blood pressure, the previous international consensus statement was not adhered to routinely.     

Maternal temperature in emergency caesarean section (MATES): an observational multicentre study

BackgroundTemperature regulation in women undergoing emergency caesarean section is a complex topic about which there is a paucity of evidence-based recommendations. The adverse effects of inadvertent peri-operative hypothermia are well described. Hyperthermia is also associated with adverse neonatal outcomes, an increased risk of obstetric intervention and increased treatment for suspected sepsis. We conducted a multi-centre observational cohort study to identify the prevalence of hypothermia and hyperthermia during emergency caesarean section.sParticipants undergoing emergency caesarean section were recruited across 14 sites in the UK. The primary end point was maternal temperature in the recovery room. Temperature was measured using a zero heat-flux temperature monitoring device.ResultsTwo hundred and sixty-five participants were recruited over a 12-month period. The prevalence of hypothermia (<36.0°C) was 10.7% and the prevalence of hyperthermia (>37.5°C) was 14.7% on admission to recovery. The prevalence of hypothermia, normothermia, and hyperthermia differed among type of anaesthesia: 71.4% of the hypothermic group had received a spinal anaesthetic whereas 76.9% of the hyperthermic group had received epidural top-up anaesthesia. There was a significant decrease in maternal temperature between the time of delivery and admission to the recovery room of 0.20°C (95% CI 0.15 to 0.25, P<0.001).ConclusionsBoth hypothermia and hyperthermia are prevalent findings in mothers who undergo emergency caesarean section. Therefore, accurate temperature measurement is essential to ensure that an appropriate intra-operative temperature management strategy is employed.     

Estimation of blood haemoglobin concentration using the HemoCue® during caesarean section: the effect of sampling site

BackgroundHaemoglobin concentration measured using the HemoCue® is accurate for capillary and venous/arterial blood, provided the recommended sampling method is strictly observed. Analysis of blood, particularly of capillary samples, using the HemoCue® is useful during caesarean section. The toe might be preferred to the thumb since it is numb during neuraxial anaesthesia, but whether sampling at either site is accurate in this situation, given the cardiovascular effects of anaesthesia and pregnancy, is not known. We aimed to compare haemoglobin values measured in venous and capillary samples (toe and thumb) during caesarean section under neuraxial anaesthesia.MethodFifty healthy women having caesarean section under spinal or combined spinal-epidural anaesthesia were included. At the end of surgery, the great toe and thumb (non-i.v. fluid side) were lanced as recommended for a HemoCue® reading. A venous blood sample (non-i.v. fluid side) was also taken and sent for formal laboratory measurement and tested with the HemoCue®. Bland-Altman analysis was applied to the haemoglobin values.ResultsBias (mean difference) and precision ± 2 SD were respectively 0.2 ±1.6 for laboratory vs. toe, 0.1 ±1.8 for laboratory vs. thumb, and 0.2 ±1.6 laboratory vs. venous.ConclusionOur results suggest that in terms of accuracy, the two sites are equally suitable for use during caesarean section under neuraxial anaesthesia.     

Neonatal outcomes following phenylephrine or norepinephrine for treatment of spinal anaesthesia-induced hypotension at emergency caesarean section in women with fetal compromise: a randomised controlled study

BackgroundNorepinephrine is as effective as phenylephrine for management of spinal anaesthesia-induced hypotension. Most of the studies comparing these vasopressors have been conducted in healthy pregnant women undergoing elective caesarean section. In the current study, we tested the null hypothesis that there is no difference in neonatal outcome when phenylephrine or norepinephrine is used to treat spinal anaesthesia-induced hypotension in women undergoing emergency caesarean section for fetal compromise.MethodsPatients undergoing caesarean section for fetal compromise who developed spinal anaesthesia-induced hypotension were randomised to receive phenylephrine 100 μg or norepinephrine 8 μg for treatment of each hypotensive episode, defined as systolic blood pressure <100 mmHg. Umbilical cord arterial and venous blood samples were obtained for blood gas analysis. The primary outcome measure was umbilical artery pH.ResultsOne hundred patients (50 in each group) were studied. There was no significant difference in umbilical artery pH between the two groups (mean difference 0.001; 95% CI −0.032 to 0.034). The number of hypotensive episodes, vasopressor boluses required, the incidence of bradycardia, heart rate and blood pressure trends following vasopressor administration, and the incidence of nausea/vomiting were not significantly different between groups.ConclusionPhenylephrine 100 μg and norepinephrine 8 μg were not significantly different in terms of neonatal outcome when administered as intravenous boluses for treatment of spinal anaesthesia-induced hypotension in parturients undergoing emergency caesarean sections for fetal compromise.     

Retrospective study of association between choice of vasopressor given during spinal anaesthesia for high-risk caesarean delivery and fetal pH

BackgroundPhenylephrine given during spinal anaesthesia for low-risk caesarean section is associated with higher fetal pH than ephedrine. However, there is little evidence on the effects of ephedrine and phenylephrine in complicated pregnancies. The aim of this study was to compare umbilical artery pH with phenylephrine and ephedrine given during spinal anaesthesia where caesarean section was performed because of an increased risk of fetal compromise.MethodsWe reviewed the case notes of all women at our hospital from 2000-2003 who had undergone high-risk caesarean section under spinal anaesthesia, where umbilical artery and venous pH had been recorded at delivery. Umbilical artery pH was compared by choice of vasopressor and multiple regression analysis was used to investigate the effects of other possible confounding variables.ResultsOne hundred and fifteen patients received no vasopressor, 122 ephedrine (group E) and 148 phenylephrine (group P). The median umbilical artery pH was 7.26 (IQR 7.21–7.30) for the no-vasopressor group, 7.27 (7.22–7.30) for group E and 7.28 (7.22–7.32) for group P (P=0.21). Using multiple regression analysis, the only variable associated with altered umbilical artery pH was a non-reassuring fetal heart trace.ConclusionsUmbilical artery pH was similar whether ephedrine or phenylephrine was used to maintain maternal arterial pressure, which contrasts with studies of low-risk caesarean section.     

Obstetric anaesthesia outcome in obese and non-obese parturients undergoing caesarean delivery: an observational study

BackgroundMaternal obesity is increasing in prevalence and is associated with an increased risk of perioperative complications. This study evaluates the impact of obesity on perioperative outcomes in parturients undergoing caesarean delivery.MethodsIn this prospective observational study of 1477 consecutive caesarean deliveries, data collected included body mass index, co-morbidities, anaesthetic technique, perioperative complications and patient satisfaction. Outcome measures included obesity prevalence, association of obesity with caesarean delivery, co-morbidities, perioperative complications and patient satisfaction and were compared between the obese and non-obese groups.ResultsThe prevalence of obesity was 54.3%, including 7.2% morbidly obese. About 61% of parturients who underwent caesarean delivery because of failure to progress in labour or previous caesarean were obese. The overall prevalence of co-morbidity was 10.2% of whom 57.3% were obese. Neuraxial anaesthesia was used in 73.4% and general anaesthesia in 26.6%, similar in obese and non-obese. The epidural failure rate was 4.3% and the spinal failure rate 2.9%. Difficulty in performing neuraxial anaesthesia was greater in obese patients (P = 0.004). There was no association between obesity and laryngoscopy grades. Patient satisfaction was similar in the obese and non-obese groups. Postoperative complications were minimal and similar.ConclusionsNeuraxial anaesthesia was effective for caesarean deliveries in obese and non-obese, in elective and emergency cases. Maternal obesity is associated with increased difficulty in performing neuraxial anaesthesia, but not with increased failure rate. Our study found no differences between obese and non-obese parturients in rate of caesarean deliveries, co-morbidities, indications for delivery or anaesthesia complications.     

Closed‐loop double‐vasopressor automated system vs manual bolus vasopressor to treat hypotension during spinal anaesthesia for caesarean section: a randomised controlled trial

Hypotension necessitating vasopressor administration occurs commonly during caesarean section under spinal anaesthesia. We developed a novel vasopressor delivery system that automatically administers phenylephrine or ephedrine based on continuous non‐invasive arterial pressure monitoring. A phenylephrine bolus of 50 μg was given at 30‐s intervals when systolic blood pressure fell < 90% of baseline; an ephedrine bolus of 4 mg was given instead if systolic pressure fell < 90% of baseline together with a heart rate < 60 beats.min^?1. The control group used manual boluses of either phenylephrine 100 μg or ephedrine 8 mg, administered at 1‐min intervals based on the same thresholds for systolic pressure and heart rate. This randomised, controlled, double‐blinded trial involved 213 healthy women who underwent elective caesarean delivery under spinal anaesthesia using 11 mg hyperbaric bupivacaine with 15 μg fentanyl and 100 μg morphine. The automated vasopressor group had better systolic pressure control, with 37/106 (34.9%) having any beat‐to‐beat systolic pressure reading < 80% of baseline compared with 63/107 (58.9%) in the control group (p < 0.001). There was no difference in the incidence of reactive hypertension, defined as systolic pressure > 120% of baseline, with 8/106 (7.5%) in the automated vasopressor group vs 14/107 (13.1%) in the control group, or total dose of vasopressors. The automated vasopressor group had lower median absolute performance error of 8.5% vs control of 9.8% (p = 0.013), and reduced incidence of nausea (1/106 (0.9%) vs 11/107 (10.3%), p = 0.005). Neonatal umbilical cord pH, umbilical lactate and Apgar scores were similar. Hence, our system afforded better control of maternal blood pressure and reduced nausea with no increase in reactive hypertension when compared with manual boluses.     

A survey of antenatal and peripartum provision of information on analgesia and anaesthesia

Pregnant women should receive information about what they might expect to experience during their delivery. Despite this, research shows many women are inadequately prepared for anaesthetic interventions during labour. We surveyed 903 postnatal women across 28 Greater London hospitals about: the analgesic and anaesthetic information that they recalled receiving during pregnancy and delivery; their confidence to make decisions on analgesia; and their satisfaction with the analgesia used. Wide variation was observed between hospitals. Overall, 67 of 749 (9.0%) women recalled receiving antenatal information covering all aspects of labour analgesia, and 108 of 889 (12.1%) covering anaesthesia for caesarean section. Regarding intrapartum information, 256 of 415 (61.7%) respondents recalled receiving thorough information before epidural insertion for labour analgesia, and 102 of 370 (27.6%) before anaesthesia for caesarean section. We found that 620 of 903 (68.7%) women felt well enough informed to be confident in their analgesic choices, and 675 of 903 (74.8%) stated that their analgesia was as expected or better. Receiving information verbally, regardless of provider, was the factor most strongly associated with respondents recalling receiving full information: odds ratio (95%CI) for labour analgesia 20.66 (8.98–47.53; p < 0.0001); epidural top-up for caesarean section 5.93 (1.57–22.35; p = 0.01); and general anaesthesia for caesarean section 12.39 (2.18–70.42; p = 0.01). A large proportion of respondents did not recall being fully informed before an anaesthetic intervention. Collaboration with current antenatal service providers, both in promoting information delivery and providing resources to assist with delivery, could improve the quality of information offered and women's retention of that information.     

Randomised trial of intravenous infusion of ephedrine or mephentermine for management of hypotension during spinal anaesthesia for Caesarean section

This study compared the effects of intravenous infusions of ephedrine and mephentermine for maintenance of maternal arterial pressure and neonatal outcome in pregnant women receiving subarachnoid block for lower segment Caesarean section. Sixty patients who developed hypotension following subarachnoid block for Caesarean section were randomly divided into two groups of 30 each to receive an intravenous infusion of ephedrine or mephentermine. Hypotension was defined as a decrease in systolic blood pressure of > or = 20% from the baseline value or an absolute value of <100 mmHg, whichever was higher. The vasopressor infusion was titrated to maintain systolic blood pressure between 'hypotension' and baseline values. Baseline haemodynamic parameters, haemodynamic changes subsequent to the start of vasopressor infusion, duration of hypotension and amount of vasopressor required were statistically similar for both groups. Neonatal APGAR scores and acid-base profiles were also comparable. To conclude, mephentermine can be used as safely and effectively as ephedrine for the management of hypotension during spinal anaesthesia in patients undergoing elective Caesarean section.     

Assessment of salivary amylase as a stress biomarker in pregnant patients

BackgroundChronic stress during pregnancy has been associated with worsened maternal and fetal outcomes. Acute stress immediately before spinal anaesthesia for caesarean section may contribute to hypotension. Therefore objective measures of acute stress may help identify women at risk of adverse outcomes. Salivary alpha-amylase is a stress biomarker that has so far been poorly investigated during pregnancy. The reference change value is the difference between two sequential results that must be exceeded for a change to be considered clinically relevant. Our first aim was to determine if salivary alpha-amylase increased in pregnant patients when subjected to the stress of transfer to the operating room. Our second aim was to determine if changes in salivary alpha-amylase were likely to be clinically significant by measuring reference change value in healthy volunteers.MethodsIn 15 pregnant patients undergoing planned caesarean section under spinal anaesthesia, salivary alpha-amylase, systolic blood pressure, heart rate, and immediate anxiety were measured on the morning of surgery on the ward and again in the operating room. The reference change value was calculated from 18 healthy volunteers.ResultsA median 220% increase in salivary alpha-amylase activity (P = 0.0015) and a 17% increase in systolic blood pressure (P = 0.0006) were observed between the ward and operating room. No changes of immediate anxiety or heart rate were observed. Reference change value was ±76% in volunteers and 13 of the 15 pregnant patients had a salivary alpha-amylase increase greater than the reference change value.ConclusionWhen pregnant women are taken to the operating room, a clinically and statistically significant increase in salivary alpha-amylase was observed. Further studies are required to define its clinical usefulness.     

Obstetric regional blocks for women with multiple sclerosis: a survey of UK experience

BACKGROUND: There has been a reluctance to use regional blocks for women with multiple sclerosis as effects on the course of the disease are unclear. We assessed the views of UK consultant obstetric anaesthetists regarding management of women with multiple sclerosis. METHODS: Following Obstetric Anaesthetists' Association approval a questionnaire was sent to UK consultant members. Opinions were sought on antenatal assessment, labour analgesia, anaesthesia for elective and emergency caesarean section, and modification in technique for those with multiple sclerosis. Enquiries were made of postnatal problems ascribed to regional blocks. RESULTS: Of the 592 replies analysed, 91% of respondents had seen fewer than 10 cases of multiple sclerosis in the past 10 years. Antenatal assessment was recommended by many with postnatal relapse most commonly discussed (64%). Many highlighted the need for informed consent and minimising local anaesthetic dose. For labour analgesia 79% would perform a regional block; a further 20% would do so in certain circumstances. For elective caesarean section, epidural rather than spinal anaesthesia was preferred by 4%; 2% would not use a regional block, preferring general anaesthesia. For emergency caesarean section with time only for single-shot spinal, 3% would give a general anaesthetic. Deterioration of symptoms after delivery were reported by 20% with 3% attributing symptoms such as prolonged block, leg weakness, bladder dysfunction and postnatal relapse to regional blocks. CONCLUSION: Most UK anaesthetists would perform regional blocks for labour and caesarean section in multiple sclerosis, although the experience of each anaesthetist is limited. Many emphasised the need for thorough pre-assessment and informed consent.     

A randomised double‐blind trial of phenylephrine and metaraminol infusions for prevention of hypotension during spinal and combined spinal–epidural anaesthesia for elective caesarean section

Prophylactic vasopressor administration is commonly recommended to reduce maternal hypotension during spinal anaesthesia for caesarean section. Metaraminol has undergone limited investigation in obstetric anaesthesia for this purpose, particularly in comparison with phenylephrine. In this multicentre, randomised, double‐blind, non‐inferiority study, we compared prophylactic phenylephrine or metaraminol infusions, started immediately after spinal anaesthesia, in 185 women who underwent elective caesarean section. Phenylephrine was initially infused at 50 μg.min^?1, and metaraminol at 250 μg.min^?1. The primary outcome was the difference in umbilical arterial pH between groups; secondary outcomes included other neonatal acid‐base measures, and maternal haemodynamic changes. The mean (SD ) umbilical arterial pH was 7.28 (0.06) in the phenylephrine group vs. 7.31 (0.04) in the metaraminol group (p = 0.0002). The estimated mean (95%CI ) pH difference of 0.03 (0.01–0.04) was above the pre‐determined lower boundary of clinical non‐inferiority, and also met the criterion for superiority. Umbilical artery lactate concentration was 2.8 (1.2) mmol.l^?1 in the phenylephrine group vs. 2.3 (0.7) mmol.l^?1 in the metaraminol group (p = 0.0018). Apgar scores did not significantly differ between groups. There was a higher incidence of hypotension, defined as systolic arterial pressure < 90% baseline, in the phenylephrine group; there was a higher incidence of hypertension and severe hypertension (systolic arterial pressure > 110% and > 120% baseline, respectively) in the metaraminol group. There was no significant difference between groups in the incidence of nausea, vomiting or maternal bradycardia. We conclude that, when used as an infusion to prevent hypotension after spinal anaesthesia for elective caesarean section, metaraminol is at least non‐inferior to phenylephrine with respect to neonatal acid‐base outcomes.     

Ephedrine and phenylephrine for avoiding maternal hypotension due to spinal anaesthesia for caesarean section. Effects on uteroplacental and fetal haemodynamics

The effects of i.v. vasopressors on Doppler velocimetry of the maternal uterine and placental arcuate arteries and the fetal umbilical, renal and middle cerebral arteries were studied during spinal anaesthesia in 19 healthy parturients undergoing elective caesarean section. Fetal myocardial function was investigated at the same time by M-mode echocardiography. The patients were randomized into two groups, to be given either ephedrine or phenylephrine as a prophylactic infusion supplemented with minor boluses if systolic arterial pressure decreased by more than 10 mmHg from the control value. Both the vasopressors restored maternal arterial pressure effectively. The ephedrine group showed no significant differences in any of the Doppler velocimetry recordings relative to the baseline values, but during the phenylephrine infusion the blood flow velocity waveform indices for the uterine and placental arcuate arteries increased significantly and vascular resistance decreased significantly in the fetal renal arteries. Healthy fetuses seem to tolerate these changes in uteroplacental circulation well, however, since the Apgar scores for the newborns and the acid-base values in the umbilical cord were within the normal range in both groups. The results suggest that some caution is required when selecting the specific vasopressor agent, the dosage and the mode of administration for the treatment of maternal hypotension secondary to spinal anaesthesia for caesarean section.     

Post-traumatic stress disorder managed successfully with hypnosis and the rewind technique: two cases in obstetric patients

Two obstetric patients presenting with post-traumatic stress disorder in the antenatal period are discussed. The first patient had previously had an unexpected stillborn delivered by emergency caesarean section under general anaesthesia. She developed post-traumatic stress disorder and presented for repeat caesarean section in her subsequent pregnancy, suffering flashbacks and severe anxiety. Following antenatal preparation with hypnosis and a psychological method called the rewind technique, she had a repeat caesarean section under spinal anaesthesia, successfully managing her anxiety. The second patient suffered post-traumatic stress disorder symptoms after developing puerperal psychosis during the birth of her first child. Before the birth of her second child, she was taught self-hypnosis, which she used during labour in which she had an uneventful water birth. These cases illustrate the potential value of hypnosis and alternative psychological approaches in managing women with severe antenatal anxiety.     

Randomised double‐blind comparison of bolus phenylephrine or ephedrine for treatment of hypotension in women with pre‐eclampsia undergoing caesarean section

Treatment of post‐spinal hypotension during caesarean section assumes special concern in pre‐eclamptic patients due to a compromised fetoplacental circulation and increased risk of placental hypoperfusion. Phenylephrine and ephedrine are the most commonly used vasopressors, although the best choice is still not clear. We studied 80 pre‐eclamptic women with a singleton pregnancy who underwent caesarean section with spinal anaesthesia, and who developed hypotension defined as a decrease in systolic arterial pressure ≥ 20% from baseline or absolute value < 100 mmHg. Women were randomly allocated to receive phenylephrine 50 μg or ephedrine 4 mg boluses for treatment of hypotension. Blood pressure changes following vasopressor administration were similar in both groups, but heart rate remained higher after ephedrine at all time‐points. The primary outcome measure of umbilical artery pH was 7.26 (0.11) in the phenylephrine group and 7.25 (0.09) in the ephedrine group (p = 0.86). The incidence of neonatal acidosis (umbilical artery pH < 7.20) was 9 (22.5%) in the phenylephrine group and 11 (27.5%) in the ephedrine group (p = 0.80). Other secondary outcome measures were comparable. In conclusion, phenylephrine 50 μg and ephedrine 4 mg, administered as intravenous boluses to treat post‐spinal hypotension during caesarean section in pre‐eclamptic patients, resulted in similar fetal acid‐base values, were equally effective in treating hypotension and were associated with good maternal and neonatal outcome.     

A survey of obstetric an aesthesia practice in Flanders

The use of locoregional anaesthesia in obstetrics in Flanders was assessed by a postal questionnaire sent to the directors of the anaesthesia departments of the 72 hospitals with an obstetric unit. 59 (82%) answers were returned. In the group of parturients who had a vaginal delivery a neuraxial technique was requested by 65% of the patients and consisted of epidural analgesia in 84%, and combined spinal epidural analgesia in 16%. Test doses are used in labour in 67%. To perform the block--spinal as well as epidural--the sitting position is somewhat preferred over the left lateral (55 versus 45%). For caesarean section general anaesthesia was used in only 5% of the deliveries, whereas spinal, single or as a part of a CSE technique, was preferred in 80%; the epidural technique was applied in 15%. There is no clear preference in technique for postoperative analgesia after caesarean delivery as both parenteral and epidural analgesia are used in 50% of the cases.     

Association of renin-angiotensin-aldosterone system genetic polymorphisms with maternal hypotension during spinal anaesthesia for caesarean delivery: a retrospective cohort study

BackgroundUnless prevented, hypotension occurs in up to 80% of normotensive women undergoing spinal anaesthesia for caesarean delivery. Renin-angiotensin-aldosterone system genetic polymorphisms have been associated with hypertensive disease, but few studies investigated effects on blood pressure regulation under spinal anaesthesia. We postulated that these polymorphisms increased vasodilation and maternal hypotension during spinal anaesthesia.MethodsA retrospective secondary analysis of data from four prospective trials with similar inclusion/exclusion criteria evaluating phenylephrine/ephedrine delivery systems during spinal anaesthesia for elective caesarean delivery. Angiotensin type-1 receptor (AT1R) (A1166C), angiotensin-converting enzyme (ACE) (I/D), and aldosterone synthase CYP11B2 (C344T) polymorphisms were identified from stored specimens. The associations between the polymorphisms and hypotension (systolic blood pressure <80% of baseline), and vasopressor use, were determined by univariable and multivariable regression.ResultsOf 556 patients, 378 (68.0%) had hypotension. The AC/CC genotypes of AT1R (A1166C) were associated with hypotension by univariable analysis (OR 2.70, 95% CI 1.38 to 5.28, P=0.004]) and multivariable analysis (OR 3.65, [95% CI 1.68 to 7.94, P=0.004]) after adjustment for age, race, intravenous fluid volume, and block height. No difference in vasopressor use or adverse maternal or fetal outcomes were noted. Baseline characteristics were similar, with the exception of higher baseline blood pressure, block height, and intravenous fluid volume in the hypotensive group. There was no significant association between ACE and CYP11B2 polymorphisms and hypotension.ConclusionAC/CC genotypes of AT1R (A1166C) polymorphism were associated with maternal hypotension under spinal anaesthesia for caesarean delivery. An association with cardiovascular indices and high-risk parturients should be examined.     

Anaesthesia for emergency caesarean section, 2000-2004, at the Royal Women's Hospital, Melbourne

The provision of anaesthesia for emergency caesarean section is a major part of the workload of obstetric anaesthetists and the urgency often dictates the mode of anaesthesia that can be provided. We have audited the provision of anaesthesia for 'immediate' caesarean sections over a four-year period following the introduction of a 'Code Green' system to coordinate a rapid response to an obstetric decision to proceed with an 'immediate' caesarean section. The records of all patients for whom a Code Green was called between July 2000 and June 2004 were studied. The reasons for the call, interval timings (for example decision-to-delivery interval) and type of anaesthesia used were collected. There were 444 Code Green procedures, of which 47 were excluded due to incomplete data. The most common indication was fetal distress' and the three most common types of anaesthesia used were general (n = 206), Epidural top-up (n = 106) and spinal (n = 65). Mean decision-to-delivery intervals (+/- SD) for all caesarean sections were 17 (+/- 6) minutes with general anaesthesia, 19 (+/- 9) minutes with epidural and 26 (+/- 9) minutes with spinal anaesthesia. Forty-five percent of calls were made between the hours of 0700 and 1700 h. General anaesthesia was most used between the hours of 0700 and 1700 h. A swift response to the call for an immediate caesarean section can be achieved when suitable facilities and procedures are in place. Administering an epidural bolus into an already established epidural catheter that is working effectively can allow a decision-to-delivery interval almost as short as general anaesthesia.     

Conversion of regional to general anaesthesia at caesarean section: increasing the use of regional anaesthesia through continuous prospective audit

BackgroundAnaesthetic-related maternal deaths have largely been attributed to complications of general anaesthesia. In our unit a retrospective audit conducted between 1997 and 2002 showed a 9.4% conversion rate to general anaesthesia for caesarean sections amongst women with epidural catheters in-situ. The Royal College of Anaesthetists has stated that <3% of cases should need conversion to general anaesthesia. To improve our figures, from 2004 to 2007 we prospectively audited all caesarean sections requiring general anaesthesia.MethodsData were collected on the number of caesarean sections, initial anaesthetic technique used, need for conversion either pre- or intra-operatively and the use of labour epidural analgesia, where an epidural had been in-situ.ResultsThere were 2273 caesarean sections during the audit period. Neuraxial anaesthesia rates were for elective cases 95.3% (2004), 96.3% (2005), 98.3% (2006) and 98.2% (2007) and for emergency cases 82.3% (2004), 88.6% (2005), 87.0% (2006) and 85.7% (2007). Common reasons given for not using a regional technique were urgency of delivery (category 1) or anticipated large blood loss. Conversion rates from regional to general anaesthesia for elective cases were 0.8% (2004), 2.5% (2005), 0.5% (2006) and 0% (2007), and for emergencies 7.8% (2004), 2.7% (2005), 3.7% (2006) and 5.4% (2007). Improvements were seen in all but category-1 caesarean sections.ConclusionsProspective audit has been associated with improved rates for neuraxial anaesthesia and reduced need for conversion to general anaesthesia in all but category-1 caesarean sections. The Royal College of Anaesthetists standards may need to be reviewed to become category-specific.     

Immediate birth – an analysis of women and their babies undergoing time critical birth in a tertiary referral obstetric hospital

BackgroundAt our institution, the emergency obstetric ‘code green’ activates the system for immediate birth, usually by caesarean section. This study aimed to determine the incidence of immediate birth, indications, modes of anaesthesia, and short-term neonatal and maternal outcomes.MethodA review was performed for all women at the Royal Women’s Hospital, Parkville, Australia who underwent immediate birth over a two-year period: January 1, 2013 to December 31, 2014.ResultsWithin the study period 14,115 women gave birth, of which 387 women underwent an immediate birth, the majority (83%) by caesarean section. The commonest indication for immediate birth was prolonged fetal bradycardia (53%), however cord prolapse (4%) produced the most rapid decision-to-delivery interval, with a median [IQR] time of 14 [13–16] min versus 18 [14–23] min for all immediate births (P < 0.01). Epidural top-up was the most common anaesthesia method. Conversion to general anaesthesia following inadequate neuraxial anaesthesia occurred in 6.2% of women. Among 103 general anaesthetics, there was one failed intubation (successful ventilation) and one dental injury. Nine women (2.3%) were admitted to the high dependency or intensive care units, and there were no maternal deaths. Babies born by caesarean section with a decision-to-delivery interval of less than 30 min were more likely to have longer times to establish respiration (22.6% vs 16.7%, P < 0.001).ConclusionRequest for immediate delivery is a common obstetric emergency. Epidural top-up has become the most common anaesthetic technique. Rapid delivery times can be achieved with an integrated emergency response system.