Hyperbaric versus isobaric bupivacaine for spinal anaesthesia for caesarean section.

BACKGROUND: Bupivacaine is an amide local anaesthetic used in hyperbaric and isobaric forms. These are administered intrathecally into the spine to provide regional anaesthesia for caesarean section. Several trials have compared hyperbaric and isobaric bupivacaine but none have conclusively shown the benefit of either. This review was first published in 2013 and updated in 2016. OBJECTIVES: Our objectives were to:1. Determine the effectiveness of hyperbaric bupivacaine compared to isobaric bupivacaine for spinal anaesthesia in women undergoing caesarean section;2. Determine the safety of hyperbaric bupivacaine compared to isobaric bupivacaine for spinal anaesthesia in women undergoing caesarean section. SEARCH METHODS: We originally searched the following databases to January 2011: CENTRAL, MEDLINE and Embase.For this update, we reran our search in the above databases from January 2011 to March 2016; two studies are awaiting a response from authors for assessment and will be dealt with when we next update the review.We imposed no language restriction. SELECTION CRITERIA: We included all randomized controlled trials (RCTs) involving parturients undergoing spinal anaesthesia for elective caesarean section that compared the use of hyperbaric with isobaric bupivacaine. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the data. The data that were extracted included the number of events and the sample sizes in both the intervention and control groups. For continuous outcomes, we extracted mean and standard deviation.We reported odds ratios (ORs) and risk ratios (RRs) for binary outcomes, and mean differences (MDs) for continuous outcomes. MAIN RESULTS: We included three new RCTs in this update, which now comprises 10 studies with a total of 614 participants. We judged most trials as having uncertain risk of bias regarding randomization. Other than this, the overall risk of bias was low. Most included trials had small sample sizes. All of the trials assessed the primary outcome of conversion to general anaesthesia. Ten trials comparing anaesthesia performed with hyperbaric and isobaric bupivacaine failed to show any difference in need for conversion to general anaesthesia (RR 0.33, 95% CI 0.09 to 1.17, 614 participants, very low quality of evidence). Nine trials also failed to show a difference in the need for supplemental analgesics (RR 0.61, 95% CI 0.26 to 1.41, 554 participants, very low quality of evidence). Four trials comparing requirement for ephedrine did not show any difference (RR 0.89, 95% CI 0.57 to 1.38, 256 participants, very low quality of evidence). Seven trials did not provide convincing evidence of difference in nausea and vomiting (RR 0.99, 95% CI 0.57 to 1.72, 433 participants, low quality of evidence). Three trials failed to show a difference in headache (OR 1.82, 95% CI 0.47 to 6.99, 234 participants, low quality of evidence). Two trials showed that the time until sensory block to the thoracic 4th (T4) spinal level was shorter with hyperbaric bupivacaine (MD -1.06 minutes, 95% CI -1.80 to -0.31, 128 participants, moderate quality of evidence). Six trials showed no difference in the amount of ephedrine used (RR 0.23, 95% CI -1.65 to 2.12, 386 participants, moderate quality of evidence). Three trials failed to show any difference in high block (RR 0.88, 95% CI 0.16 to 4.90, 205 participants). AUTHORS' CONCLUSIONS: Data are limited for some of the outcomes. Reporting of the included trials is less than optimal. For these reasons the overall quality of evidence is low or very low for most of the outcomes, based on the GRADE method of assessment. This review found that intrathecal hyperbaric bupivacaine had a more rapid onset of sensory blockade at the 4th thoracic vertebra (T4) level than isobaric bupivacaine. Hower, despite incorporating more data in the analysis, we found little evidence that the need for conversion to general anaesthesia and supplemental analgesia differed between the hyperbaric or isobaric bupivacaine groups. This is mainly due to the rarity of these outcomes, variability in the dose, use of adjuvant drugs and differences in the technique used for regional anaesthesia. There were no differences in the adverse effects studied. Any possible advantage of hyperbaric bupivacaine needs to be confirmed in larger randomized trials. In future research, criteria for conversion to general anaesthesia need to be defined objectively and applied uniformly.

Fetal vibroacoustic stimulation for facilitation of tests of fetal wellbeing.

BACKGROUND: Acoustic stimulation of the fetus has been suggested to improve the efficiency of antepartum fetal heart rate testing. OBJECTIVES: To assess the advantages and disadvantages of the use of fetal vibroacoustic stimulation in conjunction with tests of fetal wellbeing. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2013). SELECTION CRITERIA: All published and unpublished randomised controlled trials assessing the merits of the use of fetal vibroacoustic stimulation in conjunction with tests of fetal wellbeing. DATA COLLECTION AND ANALYSIS: All review authors independently extracted data and assessed trial quality. Authors of published and unpublished trials were contacted for further information. MAIN RESULTS: Altogether 12 trials with a total of 6822 participants were included. Fetal vibroacoustic stimulation reduced the incidence of non-reactive antenatal cardiotocography test (nine trials; average risk ratio (RR) 0.62, 95% confidence interval (CI) 0.48 to 0.81). Vibroacoustic stimulation compared with mock stimulation evoked significantly more fetal movements when used in conjunction with fetal heart rate testing (one trial, RR 0.23, 95% CI 0.18 to 0.29). AUTHORS' CONCLUSIONS: Vibroacoustic stimulation offers benefits by decreasing the incidence of non-reactive cardiotocography and reducing the testing time. Further randomised trials should be encouraged to determine not only the optimum intensity, frequency, duration and position of the vibroacoustic stimulation, but also to evaluate the efficacy, predictive reliability, safety and perinatal outcome of these stimuli with cardiotocography and other tests of fetal wellbeing.

Fetal manipulation for facilitating tests of fetal wellbeing.

BACKGROUND: Manual fetal manipulation has been suggested to improve the efficiency of antepartum fetal heart rate testing. OBJECTIVES: The objective of this review was to assess the merits or adverse effects of the use of manual fetal manipulation in conjunction with tests of fetal wellbeing. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2013). SELECTION CRITERIA: All published and unpublished randomised controlled trials assessing the use of fetal manipulation versus mock stimulation, no stimulation or other types of stimulation, used in conjunction with cardiotocography or other tests of fetal wellbeing. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed studies for inclusion, assessed trial quality and extracted data. Data were checked for accuracy. We contacted authors of published and unpublished trials for further information. MAIN RESULTS: We included four trials with a total of 1280 women with 2670 episodes of participation. No trial was at low risk of bias for all domains and only two trials were at low risk of bias for both selection and attrition bias.Fetal manual manipulation decreased the incidence of non-reactive antenatal cardiotocography test compared to mock or no stimulation. However, this was not statistically significant (average risk ratio (RR) 0.31, 95% confidence interval (CI) 0.02 to 6.20, I² = 96%; two trials, N = 2350). There was also no significant reduction in the mean testing time to achieve a reactive result (mean difference -2.29 minutes, 95% CI -9.61 minutes to 5.03 minutes, I² = 97%; two trials, N = 560).Comparing fetal manual manipulation with vibroacoustic stimulation, there was no significant difference in the incidence of non-reactive cardiotocography or the need for contraction-stress test.There were no data available on other outcomes such as perinatal mortality, fetal distress, maternal anxiety and gestation at delivery. AUTHORS' CONCLUSIONS: There is insufficient evidence to support the use of manual fetal manipulation during cardiotocography or other tests of fetal wellbeing. More studies of manual fetal manipulation that utilises standardised protocol should be encouraged.

Use of hyperbaric versus isobaric bupivacaine for spinal anaesthesia for caesarean section.

BACKGROUND: Bupivacaine is an amide local anaesthetic used in hyperbaric and isobaric forms. These are administered intrathecally into the spine to provide regional anaesthesia for caesarean section. Several trials have compared hyperbaric and isobaric bupivacaine but none have conclusively shown benefit of either. OBJECTIVES: This systematic review aimed to summarize the effectiveness and safety of hyperbaric versus isobaric bupivacaine in providing anaesthesia for caesarean section. We considered the adequacy of anaesthesia for completion of caesarean section and the need for interventions to treat complications. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), MEDLINE (January 1966 to May 2011) and EMBASE (January 1980 to May 2011). We handsearched journals. We imposed no language restriction. We reran our search in the above databases from January 2011 to January 2013; the studies are awaiting assessment and will be dealt with when we update the review. SELECTION CRITERIA: We included all randomized controlled trials involving parturients undergoing spinal anaesthesia for elective caesarean section that compared the use of hyperbaric with isobaric bupivacaine. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the data. The data that were extracted included the number of events and the sample sizes in both the intervention and control groups. For continuous outcomes, we extracted mean and standard deviation.We reported odds ratios and risk ratios (RR) for binary outcomes and mean differences (MD) for continuous outcomes. MAIN RESULTS: We included six studies with a total of 394 patients in this review. Anaesthesia performed with hyperbaric bupivacaine appeared to be less likely to need conversion to general anaesthesia (two studies, 158 patients included in meta-analysis; RR 0.17, 95% confidence interval (CI) 0.03 to 0.94). There was no difference in the need for supplemental analgesics. The time till sensory block to the T4 level was also shorter with hyperbaric bupivacaine (two studies, 126 patients; MD -1.06 minutes, 95% CI -1.80 to -0.31). There were no other significant differences between the two anaesthetics. AUTHORS' CONCLUSIONS: The criteria for conversion to general anaesthesia should be clearly defined in future research. This review found that intrathecal hyperbaric bupivacaine had a more rapid onset of sensory blockade at the T4 level than isobaric bupivacaine. It may also result in less need for conversion to general anaesthesia and supplemental analgesia. However, due to the rarity of this outcome, variability in the dose, use of adjuvant drugs and differences in the technique used for regional anaesthesia the evidence is weak. Any apparent advantage of hyperbaric bupivacaine needs to be confirmed in larger randomized trials. There were no differences in the adverse effects studied.

Vibroacoustic stimulation for fetal assessment in labour in the presence of a nonreassuring fetal heart rate trace.

BACKGROUND: Fetal vibroacoustic stimulation (VAS) is a simple, non-invasive technique where a device is placed on the maternal abdomen over the region of the fetal head and sound is emitted at a predetermined level for several seconds. It is hypothesised that the resultant startle reflex in the fetus and subsequent fetal heart rate (FHR) acceleration or transient tachycardia following VAS provide reassurance of fetal well-being. This technique has been proposed as a tool to assess fetal well-being in the presence of a nonreassuring cardiotocographic (CTG) trace during the first and second stages of labour. OBJECTIVES: To evaluate the clinical effectiveness and safety of VAS in the assessment of fetal well-being during labour, compared with mock or no stimulation for women with a singleton pregnancy exhibiting a nonreassuring FHR pattern. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (6 September 2012) and reference lists of all retrieved articles. We sought unpublished trials and abstracts submitted to major international congresses and contacted expert informants. SELECTION CRITERIA: All published and unpublished randomised trials that compared maternal and fetal/neonatal/infant outcomes when VAS was used to evaluate fetal status in the presence of a nonreassuring CTG trace during labour, compared with mock or no stimulation. DATA COLLECTION AND ANALYSIS: Two review authors independently sought to assess for inclusion all the potential studies we identified as a result of the search strategy. We planned to resolve any disagreement through discussion or, if required, to consult a third person. Where there was uncertainty about a particular study, we attempted to contact study authors for additional information. However, these attempts were unsuccessful. MAIN RESULTS: The search strategies yielded six studies for consideration of inclusion. However, none of these studies fulfilled the requirements for inclusion in this review. AUTHORS' CONCLUSIONS: There are currently no randomised controlled trials that address the safety and efficacy of VAS used to assess fetal well-being in labour in the presence of a nonreassuring CTG trace. Although VAS has been proposed as a simple, non-invasive tool for assessment of fetal well-being, there is insufficient evidence from randomised trials on which to base recommendations for use of VAS in the evaluation of fetal well-being in labour in the presence of a nonreassuring CTG trace.

Maternal glucose administration for facilitating tests of fetal wellbeing.

BACKGROUND: Antenatal maternal glucose administration has been suggested to improve the efficiency of antepartum fetal heart rate testing. OBJECTIVES: The objective of this review was to assess the merits or adverse effects of antenatal maternal glucose administration in conjunction with tests of fetal wellbeing. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (6 July 2012). SELECTION CRITERIA: All published and unpublished randomized controlled trials assessing the merits of antenatal maternal (oral or intravenous) glucose administration in conjunction with tests of fetal wellbeing. DATA COLLECTION AND ANALYSIS: Both review authors independently extracted data and assessed trial quality. Authors of published and unpublished trials were contacted for further information. MAIN RESULTS: A total of two trials, involving 708 participants, were included. Antenatal maternal glucose administration did not decrease the incidence of non-reactive antenatal cardiotocography tests. AUTHORS' CONCLUSIONS: Antenatal maternal glucose administration has not been shown to reduce non-reactive cardiotocography. More trials are needed to further substantiate this and to determine not only the optimum dose, but also to evaluate the efficacy, predictive reliability, safety and perinatal outcome of glucose administration in conjunction with cardiotocography and also other tests of fetal wellbeing.

Absence of cochleotoxicity measured by standard and high-frequency pure tone audiometry in a trial of once- versus three-times-daily tobramycin in cystic fibrosis patients.

We undertook assessment of hearing in patients with cystic fibrosis who were taking part in a large randomized controlled trial of once- versus three-times-daily tobramycin for pulmonary exacerbations of cystic fibrosis (the TOPIC study). All patients were eligible to have standard pure tone audiometry performed across the frequency range of 0.25 to 8 kHz. High-frequency pure tone audiometry over 10 to 16 kHz was also performed with a subset of patients. Audiometry was undertaken at the start of tobramycin treatment, at the end of a 14-day course of treatment, and at follow-up 6 to 8 weeks later. We enrolled 244 patients, of whom 219 (125 children and 94 adults) completed treatment. Nineteen patients were excluded from analysis due to abnormal baseline audiometry. Complete pre- and posttreatment standard audiological data were obtained for 168/219 patients. We found no significant differences in hearing thresholds when they were assessed at the baseline, at the end of treatment, and at follow-up 6 to 8 weeks later were compared. In addition, no significant differences in hearing thresholds were detected between treatment regimens. Similar results were obtained for the subset of 63/168 patients who underwent high-frequency audiometry. We conclude that for a single 14-day course of tobramycin treatment in patients with cystic fibrosis with no preexisiting auditory deficit, no measurable effect on hearing was apparent with either once- or three-times-daily treatment. Estimation of the cumulative cochleotoxic risk in cystic fibrosis patients due to repeated aminoglycoside therapy, as evidenced by the patients excluded from this study due to hearing loss, also requires further characterization.

Once versus three-times daily regimens of tobramycin treatment for pulmonary exacerbations of cystic fibrosis--the TOPIC study: a randomised controlled trial.

BACKGROUND: Intravenous tobramycin (three-times daily) is widely used for pulmonary exacerbations in patients with cystic fibrosis who have chronic Pseudomonas aeruginosa infection. We undertook a double-blind, randomised controlled trial to assess the safety and efficacy of once versus three-times daily tobramycin in these patients. METHODS: 244 patients from 21 cystic-fibrosis centres in the UK were randomly assigned to once or three-times daily tobramycin (with ceftazidime) for 14 days. Treatment was given as 30-min infusions of tobramycin in 0.9% saline. Primary outcome measure was change in forced expiratory volume in 1s (FEV1), over the 14 days of treatment, expressed as a percentage of the predicted normal value for age, sex, and height. We also measured the change in FEV1 expressed as a percentage of baseline. Secondary outcomes included change in serum creatinine. The study was powered for equivalence, and primary analysis was per protocol. FINDINGS: 219 patients (107 once daily, 112 three-times daily) completed the study per protocol. None was lost to follow-up, although 20 discontinued intervention. Of 122 patients assigned to once daily treatment, three did not receive the study regimen. The mean change in FEV1 (% predicted) over 14 days was similar on the two regimens (10.4% [once daily] vs 10.0% [three-times daily]; adjusted mean difference 0.4% [95% CI -3.3 to 4.1]). Mean% change in FEV1 from baseline was also similar in both treatments (21.9% vs 22.1%; -0.1% [-8.0 to 7.9]). There was no significant difference in% change in creatinine from baseline (-1.5% [once daily] vs 1.7% [three-times daily]). However, in children, once daily treatment was significantly less nephrotoxic than was thrice daily (mean% change in creatine -4.5% [once daily] vs 3.7% [thrice daily]; adjusted mean difference -8.0%, 95% CI -15.7 to -0.4). No patients developed hearing loss during the study, although two reported acute dizziness and were withdrawn from the study. INTERPRETATION: Intravenous tobramycin has equal efficacy if given once or three-times daily (with ceftazidime) for pulmonary exacerbations of cystic fibrosis. The once daily regimen might be less nephrotoxic in children.