1
|
Vignarajah M, Berg A, Abdallah Z, Arora N, Javidan A, Pitre T, Fernando SM, Spence J, Centofanti J, Rochwerg B. Intraoperative use of balanced crystalloids versus 0.9% saline: a systematic review and meta-analysis of randomised controlled studies. Br J Anaesth 2023; 131:463-471. [PMID: 37455198 DOI: 10.1016/j.bja.2023.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 04/29/2023] [Accepted: 05/24/2023] [Indexed: 07/18/2023] Open
Abstract
BACKGROUND The evidence regarding optimal crystalloid use in the perioperative period remains unclear. As the primary aim of this study, we sought to summarise the data from RCTs examining whether use of balanced crystalloids compared with 0.9% saline (saline) leads to differences in patient-important outcomes. METHODS We searched Ovid MEDLINE, Embase, the Cochrane library, and Clinicaltrials.gov, from inception until December 15, 2022, and included RCTs that intraoperatively randomised adult participants to receive either balanced fluids or saline. We pooled data using a random-effects model and present risk ratios (RRs) or mean differences (MDs), along with 95% confidence intervals (CIs). We assessed individual study risk of bias using the modified Cochrane tool, and certainty of evidence using GRADE. RESULTS Of 5959 citations, we included 38 RCTs (n=3776 patients). Pooled analysis showed that intraoperative use of balanced fluids compared with saline had an uncertain effect on postoperative mortality analysed at the longest point of follow-up (RR 1.51, 95% CI: 0.42-5.36) and postoperative need for renal replacement therapy (RR 0.95, 95% CI: 0.56-1.59), both very low certainty. Furthermore, use of balanced crystalloids probably leads to a higher postoperative serum pH (MD 0.05, 95% CI: 0.04-0.06), moderate certainty. CONCLUSIONS Use of balanced crystalloids, compared with saline, in the perioperative setting has an uncertain effect on mortality and need for renal replacement therapy but probably improves postoperative acid-base status. Further research is needed to determine whether balanced crystalloid use affects patient-important outcomes. CLINICAL TRIAL REGISTRATION CRD42022367593.
Collapse
Affiliation(s)
| | - Annie Berg
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - Zahra Abdallah
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - Naman Arora
- Department of Emergency Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Arshia Javidan
- Division of Vascular Surgery, Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Tyler Pitre
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - Shannon M Fernando
- Division of Critical Care, Department of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Jessica Spence
- Department of Anaesthesia, McMaster University, Hamilton, ON, Canada; Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada
| | - John Centofanti
- Department of Medicine, McMaster University, Hamilton, ON, Canada; Department of Anaesthesia, McMaster University, Hamilton, ON, Canada
| | - Bram Rochwerg
- Department of Medicine, McMaster University, Hamilton, ON, Canada; Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada.
| |
Collapse
|
2
|
Incidence and factors associated with hypotension in emergency patients that underwent cesarean section with spinal anaesthesia: Prospective observational study. INTERNATIONAL JOURNAL OF SURGERY OPEN 2021. [DOI: 10.1016/j.ijso.2021.100378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
3
|
Chooi C, Cox JJ, Lumb RS, Middleton P, Chemali M, Emmett RS, Simmons SW, Cyna AM. Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev 2020; 7:CD002251. [PMID: 32619039 PMCID: PMC7387232 DOI: 10.1002/14651858.cd002251.pub4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury). OBJECTIVES To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section. SEARCH METHODS We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies. SELECTION CRITERIA Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure. DATA COLLECTION AND ANALYSIS Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE. MAIN RESULTS We included 125 studies involving 9469 women. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids) Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloid Fewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.69, 95% CI 0.58 to 0.81; 2009 women; 27 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women; very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.98, 95% CI 0.54 to 1.78, 5 studies, 413 women; very low-quality evidence), nausea and/or vomiting (average RR 0.89, 95% CI 0.66 to 1.19, 14 studies, 1058 women, I² = 29%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 10 studies, 730 babies; very low-quality evidence). Ephedrine versus phenylephrine There were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus control Ondansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus control Lower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42, 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lying There was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence). Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections. External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration. AUTHORS' CONCLUSIONS While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.
Collapse
Affiliation(s)
- Cheryl Chooi
- Department of Women's Anaesthesia, Women's and Children's Hospital, Adelaide, Australia
| | - Julia J Cox
- Department of Women's Anaesthesia, Women's and Children's Hospital, Adelaide, Australia
| | - Richard S Lumb
- Department of Women's Anaesthesia, Women's and Children's Hospital, Adelaide, Australia
| | - Philippa Middleton
- Healthy Mothers, Babies and Children, South Australian Health and Medical Research Institute, Adelaide, Australia
| | | | - Richard S Emmett
- Department of Women's Anaesthesia, Women's and Children's Hospital, Adelaide, Australia
| | - Scott W Simmons
- Department of Anaesthesia, Mercy Hospital for Women, Heidelberg, Australia
| | - Allan M Cyna
- Department of Women's Anaesthesia, Women's and Children's Hospital, Adelaide, Australia
- University of Sydney, Sydney, Australia
| |
Collapse
|
4
|
Chooi C, Cox JJ, Lumb RS, Middleton P, Chemali M, Emmett RS, Simmons SW, Cyna AM. Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev 2017; 8:CD002251. [PMID: 28976555 PMCID: PMC6483677 DOI: 10.1002/14651858.cd002251.pub3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. It can be associated with nausea or vomiting and may pose serious risks to the mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis, neurological injury). OBJECTIVES To assess the effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section. SEARCH METHODS We searched Cochrane Pregnancy and Childbirth's Trials Register (9 August 2016) and reference lists of retrieved studies. SELECTION CRITERIA Randomised controlled trials, including full texts and abstracts, comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section. We excluded studies if hypotension was not an outcome measure. DATA COLLECTION AND ANALYSIS Two review authors independently assessed study quality and extracted data from eligible studies. We report 'Summary of findings' tables using GRADE. MAIN RESULTS We included 126 studies involving 9565 participants. Interventions were to prevent maternal hypotension following spinal anaesthesia only, and we excluded any interventions considered active treatment. All the included studies reported the review's primary outcome. Across 49 comparisons, we identified three intervention groups: intravenous fluids, pharmacological interventions, and physical interventions. Authors reported no serious adverse effects with any of the interventions investigated. Most trials reported hypotension requiring intervention and Apgar score of less than 8 at five minutes as the only outcomes. None of the trials included in the comparisons we describe reported admission to neonatal intensive care unit. Crystalloid versus control (no fluids)Fewer women experienced hypotension in the crystalloid group compared with no fluids (average risk ratio (RR) 0.84, 95% confidence interval (CI) 0.72 to 0.98; 370 women; 5 studies; low-quality evidence). There was no clear difference between groups in numbers of women with nausea and vomiting (average RR 0.19, 95% CI 0.01 to 3.91; 1 study; 69 women; very low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (60 babies, low-quality evidence). Colloid versus crystalloidFewer women experienced hypotension in the colloid group compared with the crystalloid group (average RR 0.68, 95% CI 0.58 to 0.80; 2105 women; 28 studies; very low-quality evidence). There were no clear differences between groups for maternal hypertension requiring intervention (average RR 0.64, 95% CI 0.09 to 4.46, 3 studies, 327 women;very low-quality evidence), maternal bradycardia requiring intervention (average RR 0.99, 95% CI 0.55 to 1.79, 6 studies, 509 women; very low-quality evidence), nausea and/or vomiting (average RR 0.83, 95% CI 0.61 to 1.13, 15 studies, 1154 women, I² = 37%; very low-quality evidence), neonatal acidosis (average RR 0.83, 95% CI 0.15 to 4.52, 6 studies, 678 babies; very low-quality evidence), or Apgar score of less than 8 at five minutes (average RR 0.24, 95% CI 0.03 to 2.05, 11 studies, 826 babies; very low-quality evidence). Ephedrine versus phenylephrineThere were no clear differences between ephedrine and phenylephrine groups for preventing maternal hypotension (average RR 0.92, 95% CI 0.71 to 1.18; 401 women; 8 studies; very low-quality evidence) or hypertension (average RR 1.72, 95% CI 0.71 to 4.16, 2 studies, 118 women, low-quality evidence). Rates of bradycardia were lower in the ephedrine group (average RR 0.37, 95% CI 0.21 to 0.64, 5 studies, 304 women, low-quality evidence). There was no clear difference in the number of women with nausea and/or vomiting (average RR 0.76, 95% CI 0.39 to 1.49, 4 studies, 204 women, I² = 37%, very low-quality evidence), or babies with neonatal acidosis (average RR 0.89, 95% CI 0.07 to 12.00, 3 studies, 175 babies, low-quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (321 babies; low-quality evidence). Ondansetron versus controlOndansetron administration was more effective than control (placebo saline) for preventing hypotension requiring treatment (average RR 0.67, 95% CI 0.54 to 0.83; 740 women, 8 studies, low-quality evidence), bradycardia requiring treatment (average RR 0.49, 95% CI 0.28 to 0.87; 740 women, 8 studies, low-quality evidence), and nausea and/or vomiting (average RR 0.35, 95% CI 0.24 to 0.51; 653 women, 7 studies, low-quality evidence). There was no clear difference between the groups in rates of neonatal acidosis (average RR 0.48, 95% CI 0.05 to 5.09; 134 babies; 2 studies, low-quality evidence) or Apgar scores of less than 8 at five minutes (284 babies, low-quality evidence). Lower limb compression versus controlLower limb compression was more effective than control for preventing hypotension (average RR 0.61, 95% CI 0.47 to 0.78, 11 studies, 705 women, I² = 65%, very low-quality evidence). There was no clear difference between the groups in rates of bradycardia (RR 0.63, 95% CI 0.11 to 3.56, 1 study, 74 women, very low-quality evidence) or nausea and/or vomiting (average RR 0.42 , 95% CI 0.14 to 1.27, 4 studies, 276 women, I² = 32%, very-low quality evidence). No baby had an Apgar score of less than 8 at five minutes in either group (130 babies, very low-quality evidence). Walking versus lyingThere was no clear difference between the groups for women with hypotension requiring treatment (RR 0.71, 95% CI 0.41 to 1.21, 1 study, 37 women, very low-quality evidence).Many included studies reported little to no information that would allow an assessment of their risk of bias, limiting our ability to draw meaningful conclusions. GRADE assessments of the quality of evidence ranged from very low to low. We downgraded evidence for limitations in study design, imprecision, and indirectness; most studies assessed only women scheduled for elective caesarean sections.External validity also needs consideration. Readers should question the use of colloids in this context given the serious potential side effects such as allergy and renal failure associated with their administration. AUTHORS' CONCLUSIONS While interventions such as crystalloids, colloids, ephedrine, phenylephrine, ondansetron, or lower leg compression can reduce the incidence of hypotension, none have been shown to eliminate the need to treat maternal hypotension in some women. We cannot draw any conclusions regarding rare adverse effects associated with use of the interventions (for example colloids) due to the relatively small numbers of women studied.
Collapse
Affiliation(s)
- Cheryl Chooi
- Women's and Children's HospitalDepartment of Women's Anaesthesia72 King William RoadAdelaideAustralia5006
| | - Julia J Cox
- Women's and Children's HospitalDepartment of Women's Anaesthesia72 King William RoadAdelaideAustralia5006
| | - Richard S Lumb
- Women's and Children's HospitalDepartment of Women's Anaesthesia72 King William RoadAdelaideAustralia5006
| | - Philippa Middleton
- Healthy Mothers, Babies and Children, South Australian Health and Medical Research InstituteWomen's and Children's Hospital72 King William RoadAdelaideSouth AustraliaAustralia5006
| | - Mark Chemali
- Royal North Shore HospitalReserve RoadSt LeonardsSydneyNSWAustralia2065
| | - Richard S Emmett
- Women's and Children's HospitalDepartment of Women's Anaesthesia72 King William RoadAdelaideAustralia5006
| | - Scott W Simmons
- Mercy Hospital for WomenDepartment of Anaesthesia163 Studley RoadHeidelbergVictoriaAustralia3084
| | - Allan M Cyna
- Women's and Children's HospitalDepartment of Women's Anaesthesia72 King William RoadAdelaideAustralia5006
- University of SydneySydneyAustralia
| | | |
Collapse
|
5
|
Reddy S, Weinberg L, Young P. Crystalloid fluid therapy. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2016; 20:59. [PMID: 26976277 PMCID: PMC4791913 DOI: 10.1186/s13054-016-1217-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.
Collapse
Affiliation(s)
- Sumeet Reddy
- Medical Research Institute of New Zealand, 6021, Wellington, New Zealand.
| | - Laurence Weinberg
- Austin Hospital, Department of Anesthesia, Melbourne, VIC, Australia.,Departments of Surgery and Anesthesia, University of Melbourne, Perioperative Pain Medicine Unit, Melbourne, VIC, Australia
| | - Paul Young
- Medical Research Institute of New Zealand, 6021, Wellington, New Zealand.,Wellington Regional Hospital, Intensive Care Unit, Wellington, New Zealand
| |
Collapse
|
6
|
Orbegozo Cortés D, Rayo Bonor A, Vincent JL. Isotonic crystalloid solutions: a structured review of the literature. Br J Anaesth 2014; 112:968-81. [PMID: 24736393 DOI: 10.1093/bja/aeu047] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Several different crystalloid solutions are available for i.v. fluid administration but there is little information about their specific advantages and disadvantages. METHODS We performed a systematic search of MEDLINE, EMBASE, and CENTRAL up until May 17, 2012, selecting all prospective human studies that directly compared any near-isotonic crystalloids and reported any outcome. RESULTS From the 5060 articles retrieved in the search, only 28 met the selection criteria. There was considerable heterogeneity among the studies. Several articles reported an increased incidence of hyperchloraemic acidosis with the use of normal saline, and others an increase in blood lactate levels when large amounts of Ringer's lactate solutions were infused. From the limited data available, normal saline administration appears to be associated with increased blood loss and greater red blood cell transfusion volumes in high-risk populations compared to Ringer's lactate. Possible effects of the different solutions on renal function, inflammatory response, temperature, hepatic function, glucose metabolism, and splanchnic perfusion are also reported. The haemodynamic profiles of all the solutions were similar. CONCLUSIONS Different solutions have different effects on acid-base status, electrolyte levels, coagulation, renal, and hepatic function. Whether these differences have clinical consequences remains unclear.
Collapse
Affiliation(s)
- D Orbegozo Cortés
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik 808, 1070 Brussels, Belgium
| | - A Rayo Bonor
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik 808, 1070 Brussels, Belgium
| | - J L Vincent
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik 808, 1070 Brussels, Belgium
| |
Collapse
|
7
|
Montoya B, Oliveros C, Moreno D. Managing hypotension induced by spinal anesthesia for caesarean section. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2009. [DOI: 10.1016/s0120-3347(09)72005-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
|
8
|
Cyna AM, Andrew M, Emmett RS, Middleton P, Simmons SW. Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev 2006:CD002251. [PMID: 17054153 DOI: 10.1002/14651858.cd002251.pub2] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
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.
Collapse
Affiliation(s)
- A M Cyna
- Women's and Children's Hospital, Department of Women's Anaesthesia, 72 King William Road, Adelaide, South Australia, Australia.
| | | | | | | | | |
Collapse
|