{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/22807"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/22807","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"The use of phenylephrine to obtund oxytocin induced hypotension and tachycardia during elective caesarean section","abstract":"Background: Oxytocin causes clinically significant hypotension and tachycardia. This study examined whether the prior administration of phenylephrine obtunds these unwanted haemodynamic effects. Methods: Forty pregnant women undergoing elective caesarean section under spinal anaesthesia were randomised to receive either a 50 μg bolus of phenylephrine (Group P) or saline (Group S) immediately prior to oxytocin (3 IU over 15 seconds). Systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP] and heart rate [HR]) were recorded using a continuous non-invasive arterial pressure device. Baseline values were averaged for 20 seconds post-delivery. Between-group comparisons were made of the mean peak changes in BP and HR, and the mean percentage changes from baseline, during the 150 seconds after oxytocin administration. Results: The mean peak percentage change (SD) in SBP was -16.9% (2%) in Group P, and -19.0% (1.9%) in Group S and the estimated mean difference was 2.1% (95% CI: -3.5 to 7.8 %) and P =0.44; corresponding changes in HR were 13.5% (2.3%) and 14.0% (1.5%) and the mean estimated difference was 0.5% (95% CI -6.0 to 5%) and P=0.87. The mean percentage change from the baseline measurements during the 150 s period of measurement was greater for Group S than Group P: SBP -5.9% vs -3.4%; P =0.149; DBP -7.2% vs -1.5%, P =0.014; MAP -6.8% vs -1.5%, P =0.007; HR 2.1% vs -2.4%, P =0.033. Conclusion: Intravenous phenylephrine 50 μg immediately before 3 U oxytocin during elective caesarean section does not prevent maternal hypotension and tachycardia.","abstract_html":"Background: Oxytocin causes clinically significant hypotension and tachycardia. This study examined whether the prior administration of phenylephrine obtunds these unwanted haemodynamic effects. Methods: Forty pregnant women undergoing elective caesarean section under spinal anaesthesia were randomised to receive either a 50 μg bolus of phenylephrine (Group P) or saline (Group S) immediately prior to oxytocin (3 IU over 15 seconds). Systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP] and heart rate [HR]) were recorded using a continuous non-invasive arterial pressure device. Baseline values were averaged for 20 seconds post-delivery. Between-group comparisons were made of the mean peak changes in BP and HR, and the mean percentage changes from baseline, during the 150 seconds after oxytocin administration. Results: The mean peak percentage change (SD) in SBP was -16.9% (2%) in Group P, and -19.0% (1.9%) in Group S and the estimated mean difference was 2.1% (95% CI: -3.5 to 7.8 %) and P =0.44; corresponding changes in HR were 13.5% (2.3%) and 14.0% (1.5%) and the mean estimated difference was 0.5% (95% CI -6.0 to 5%) and P=0.87. The mean percentage change from the baseline measurements during the 150 s period of measurement was greater for Group S than Group P: SBP -5.9% vs -3.4%; P =0.149; DBP -7.2% vs -1.5%, P =0.014; MAP -6.8% vs -1.5%, P =0.007; HR 2.1% vs -2.4%, P =0.033. Conclusion: Intravenous phenylephrine 50 μg immediately before 3 U oxytocin during elective caesarean section does not prevent maternal hypotension and tachycardia.","abstract_has_math":false,"creators":["Rumboll, Charles Knight"],"institution":"Department of Anaesthesia","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Dyer, Robert A"],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016","date_published":"2016","updated_at":"2026-07-22T22:22:49Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/22807","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Dyer, Robert A"]},{"key":"dc:creator","label":"Author","values":["Rumboll, Charles Knight"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2017-01-19T12:17:06Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2017-01-19T12:17:06Z"]},{"key":"dc:date.issued","label":"Date","values":["2016"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Anaesthesia"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["MMed"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/22807"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Background: Oxytocin causes clinically significant hypotension and tachycardia. This study examined whether the prior administration of phenylephrine obtunds these unwanted haemodynamic effects. Methods: Forty pregnant women undergoing elective caesarean section under spinal anaesthesia were randomised to receive either a 50 μg bolus of phenylephrine (Group P) or saline (Group S) immediately prior to oxytocin (3 IU over 15 seconds). Systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP] and heart rate [HR]) were recorded using a continuous non-invasive arterial pressure device. Baseline values were averaged for 20 seconds post-delivery. Between-group comparisons were made of the mean peak changes in BP and HR, and the mean percentage changes from baseline, during the 150 seconds after oxytocin administration. Results: The mean peak percentage change (SD) in SBP was -16.9% (2%) in Group P, and -19.0% (1.9%) in Group S and the estimated mean difference was 2.1% (95% CI: -3.5 to 7.8 %) and P =0.44; corresponding changes in HR were 13.5% (2.3%) and 14.0% (1.5%) and the mean estimated difference was 0.5% (95% CI -6.0 to 5%) and P=0.87. The mean percentage change from the baseline measurements during the 150 s period of measurement was greater for Group S than Group P: SBP -5.9% vs -3.4%; P =0.149; DBP -7.2% vs -1.5%, P =0.014; MAP -6.8% vs -1.5%, P =0.007; HR 2.1% vs -2.4%, P =0.033. Conclusion: Intravenous phenylephrine 50 μg immediately before 3 U oxytocin during elective caesarean section does not prevent maternal hypotension and tachycardia."]},{"key":"dc:title","label":"Title","values":["The use of phenylephrine to obtund oxytocin induced hypotension and tachycardia during elective caesarean section"]}]}],"canonical_facts":{"dc:contributor.advisor":["Dyer, Robert A"],"dc:creator":["Rumboll, Charles Knight"],"dc:date.accessioned":["2017-01-19T12:17:06Z"],"dc:date.available":["2017-01-19T12:17:06Z"],"dc:date.issued":["2016"],"dc:description.abstract":["Background: Oxytocin causes clinically significant hypotension and tachycardia. This study examined whether the prior administration of phenylephrine obtunds these unwanted haemodynamic effects. Methods: Forty pregnant women undergoing elective caesarean section under spinal anaesthesia were randomised to receive either a 50 μg bolus of phenylephrine (Group P) or saline (Group S) immediately prior to oxytocin (3 IU over 15 seconds). Systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP] and heart rate [HR]) were recorded using a continuous non-invasive arterial pressure device. Baseline values were averaged for 20 seconds post-delivery. Between-group comparisons were made of the mean peak changes in BP and HR, and the mean percentage changes from baseline, during the 150 seconds after oxytocin administration. Results: The mean peak percentage change (SD) in SBP was -16.9% (2%) in Group P, and -19.0% (1.9%) in Group S and the estimated mean difference was 2.1% (95% CI: -3.5 to 7.8 %) and P =0.44; corresponding changes in HR were 13.5% (2.3%) and 14.0% (1.5%) and the mean estimated difference was 0.5% (95% CI -6.0 to 5%) and P=0.87. The mean percentage change from the baseline measurements during the 150 s period of measurement was greater for Group S than Group P: SBP -5.9% vs -3.4%; P =0.149; DBP -7.2% vs -1.5%, P =0.014; MAP -6.8% vs -1.5%, P =0.007; HR 2.1% vs -2.4%, P =0.033. Conclusion: Intravenous phenylephrine 50 μg immediately before 3 U oxytocin during elective caesarean section does not prevent maternal hypotension and tachycardia."],"dc:identifier.uri":["http://hdl.handle.net/11427/22807"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Anaesthesia"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["The use of phenylephrine to obtund oxytocin induced hypotension and tachycardia during elective caesarean section"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters"],"dc:type.qualificationname":["MMed"]},"updated_at":"2026-07-22T22:22:49Z"}