The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index

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dc.contributor.advisorDyer, Robert Aen_ZA
dc.contributor.authorSamuel, Theresaen_ZA
dc.date.accessioned2017-01-27T14:19:21Z
dc.date.available2017-01-27T14:19:21Z
dc.date.issued2016en_ZA
dc.description.abstractBackground: We compared the accuracy and precision of estimation of the systolic blood pressure (SBP) by disappearance of the pulse oximeter trace (DOT), with noninvasive blood pressure (NIBP) measurement, across the range of body mass index (BMI), during spinal anaesthesia (SA) for caesarean section (CS). Methods: Three groups of 25 parturients were recruited, with BMI of < 30- (Group 1), 30-40- (Group 2), and > 40 kg/m2 (Group 3) respectively. SBP was measured using the DASH® 3000 monitor (GE Health Care, UK) NIBP monitor, placed on the same arm as the pulse oximeter probe. Estimations of SBP were done before- and 5 minutes after induction of SA, during cuff inflation and deflation. The times taken for the estimations and the actual NIBP measurements were noted. Bland and Altman analysis was performed and the correlation coefficient estimated. Results: Concerning the most clinically relevant estimation, namely SBP during inflation post-SA: For Groups 1, 2 and 3, r = 0.56, 0.74 and 0.91; bias = -0.4, -2.9 and 0.8 mmHg, and limits of agreement = -27.7 to 26.9, -27.7 to 21.9 and -15.9 to 17.5 mmHg respectively. The mean (SD) time required for estimation of the SBP during inflation post- SA was 7.5 (1.1) s, 11.8 (3.8) s and 16.8 (4.2) s in the Groups 1, 2 and 3 respectively. The mean (SD) time required for measurement of post-SA SBP during inflations in Groups 1, 2 and 3, was 30.3 (13.1) s, 41.3 (10.2) s and 49.8 (14.6) respectively. In the post-SA period, mean time saved by estimating SBP during inflation was approximately 28.5 seconds, compared with 9 seconds during deflation. The time saved in Groups 1, 2 and 3 was 22.8 (13.2) s, 30.0 (11.6) s and 33.0 (15.6) s respectively. In the BMI > 40 kg/m2 group, the percentage error is ±13% of the mean systolic blood pressure observed, and the absolute error is ±16 mmHg, compared to ±27 mmHg in the normal BMI group. Conclusion: Post-SA estimation of SBP during cuff inflation in morbidly obese patients is more accurate and precise than in the other BMI Groups. Time to estimation is shorter than measurement by a clinically relevant period (33 s). This should improve patient safety in morbidly obese parturients.en_ZA
dc.identifier.apacitationSamuel, T. (2016). <i>The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Department of Anaesthesia. Retrieved from http://hdl.handle.net/11427/23653en_ZA
dc.identifier.chicagocitationSamuel, Theresa. <i>"The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Department of Anaesthesia, 2016. http://hdl.handle.net/11427/23653en_ZA
dc.identifier.citationSamuel, T. 2016. The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Samuel, Theresa AB - Background: We compared the accuracy and precision of estimation of the systolic blood pressure (SBP) by disappearance of the pulse oximeter trace (DOT), with noninvasive blood pressure (NIBP) measurement, across the range of body mass index (BMI), during spinal anaesthesia (SA) for caesarean section (CS). Methods: Three groups of 25 parturients were recruited, with BMI of < 30- (Group 1), 30-40- (Group 2), and > 40 kg/m2 (Group 3) respectively. SBP was measured using the DASH® 3000 monitor (GE Health Care, UK) NIBP monitor, placed on the same arm as the pulse oximeter probe. Estimations of SBP were done before- and 5 minutes after induction of SA, during cuff inflation and deflation. The times taken for the estimations and the actual NIBP measurements were noted. Bland and Altman analysis was performed and the correlation coefficient estimated. Results: Concerning the most clinically relevant estimation, namely SBP during inflation post-SA: For Groups 1, 2 and 3, r = 0.56, 0.74 and 0.91; bias = -0.4, -2.9 and 0.8 mmHg, and limits of agreement = -27.7 to 26.9, -27.7 to 21.9 and -15.9 to 17.5 mmHg respectively. The mean (SD) time required for estimation of the SBP during inflation post- SA was 7.5 (1.1) s, 11.8 (3.8) s and 16.8 (4.2) s in the Groups 1, 2 and 3 respectively. The mean (SD) time required for measurement of post-SA SBP during inflations in Groups 1, 2 and 3, was 30.3 (13.1) s, 41.3 (10.2) s and 49.8 (14.6) respectively. In the post-SA period, mean time saved by estimating SBP during inflation was approximately 28.5 seconds, compared with 9 seconds during deflation. The time saved in Groups 1, 2 and 3 was 22.8 (13.2) s, 30.0 (11.6) s and 33.0 (15.6) s respectively. In the BMI > 40 kg/m2 group, the percentage error is ±13% of the mean systolic blood pressure observed, and the absolute error is ±16 mmHg, compared to ±27 mmHg in the normal BMI group. Conclusion: Post-SA estimation of SBP during cuff inflation in morbidly obese patients is more accurate and precise than in the other BMI Groups. Time to estimation is shorter than measurement by a clinically relevant period (33 s). This should improve patient safety in morbidly obese parturients. DA - 2016 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2016 T1 - The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index TI - The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index UR - http://hdl.handle.net/11427/23653 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/23653
dc.identifier.vancouvercitationSamuel T. The utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass index. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Department of Anaesthesia, 2016 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/23653en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Anaesthesiaen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherAnaesthesiologyen_ZA
dc.titleThe utility of occlusion of the pulse oximeter trace in the estimation of systolic blood pressure during spinal anaesthesia for caesarean section: the effect of body mass indexen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMMeden_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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