The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis

Simple item page
dc.contributor.advisorMyburgh, Adriaanen_ZA
dc.contributor.authorPretorius, Petrus Rohanen_ZA
dc.date.accessioned2018-01-25T06:36:16Z
dc.date.available2018-01-25T06:36:16Z
dc.date.issued2017en_ZA
dc.description.abstractBackground: The ability to correctly measure the partial pressure of Oxygen is one of the fundamental test that influence clinical decision making in a septic ICU patient. The study examined the extent of error over time, from collection to processing, when measuring blood gas samples for PO₂, PCO₂, pH, in critically-ill patients with sepsis and metabolically active leucocytosis > 12 000/mm³ and compares it with a control, where immersing it in ice has stopped metabolism. Methods: Thirty septic ICU patients with confirmed leucocytosis > 12 000/mm³, who had routine arterial blood analysed was included in the study. Blood form the standard PICO50 radiometer arterial blood sampler (2ml) syringe was decanted into two 1ml Glass syringes that was pre-heparinised with 1ml Heparin 1000U - all excess Heparin removed. One syringe was cooled with ice slurry and tested as a control at 60 minutes The other syringe was used to repeatedly analyse the sample at 0,10, 30 and 60 minutes. The syringes were sealed with plastecine and a glass capillary tube was use to decant the sample just prior to analysis to fit the analyser. Samples were processed using an ABL 800 blood gas analyser. Results: The mean absolute difference in PO₂ at 10 minutes was -0.94 kPa (95% CI: -1.48 to -0.4 kPa), at 30 minutes -2.42 kPa (95% CI: -3.10 to -1.75 kPa) and at 60 minutes -4.44 kPa (95% CI: -5.54 to -3.34 kPa). The relative difference in pO₂ at 10 minutes was -4.98% (95% CI: -8.12 to -1.84%), at 30 minutes -13.79% (95% CI: -17.40 to -10.17%) and 60 minutes -25.46% (95% CI: -30.97 to -19.95%). The absolute difference in PO₂ at 60 minutes on Ice was - 0.31 kPa. Conclusion: Delayed blood gas analysis in Septic ICU patients with a raised WCC > 12 000/mm³, results in statistical and possible clinical significant abnormality in the pO₂, that progressively worsens with time. After 10 minutes there was a 5% change, at 30 minutes a 14% change and there was a 25% change from baseline PO₂ at 60 minutes. The magnitude of change with statistical mixed linear models shows the rate of decline to be of the magnitude of 1% per minute. So at 60 minutes, the ratio change is 0.7313859 (0.9948 to the power of 60).This deviation may alter clinical decision making.en_ZA
dc.identifier.apacitationPretorius, P. R. (2017). <i>The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Department of Anaesthesia. Retrieved from http://hdl.handle.net/11427/26939en_ZA
dc.identifier.chicagocitationPretorius, Petrus Rohan. <i>"The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Department of Anaesthesia, 2017. http://hdl.handle.net/11427/26939en_ZA
dc.identifier.citationPretorius, P. 2017. The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Pretorius, Petrus Rohan AB - Background: The ability to correctly measure the partial pressure of Oxygen is one of the fundamental test that influence clinical decision making in a septic ICU patient. The study examined the extent of error over time, from collection to processing, when measuring blood gas samples for PO₂, PCO₂, pH, in critically-ill patients with sepsis and metabolically active leucocytosis > 12 000/mm³ and compares it with a control, where immersing it in ice has stopped metabolism. Methods: Thirty septic ICU patients with confirmed leucocytosis > 12 000/mm³, who had routine arterial blood analysed was included in the study. Blood form the standard PICO50 radiometer arterial blood sampler (2ml) syringe was decanted into two 1ml Glass syringes that was pre-heparinised with 1ml Heparin 1000U - all excess Heparin removed. One syringe was cooled with ice slurry and tested as a control at 60 minutes The other syringe was used to repeatedly analyse the sample at 0,10, 30 and 60 minutes. The syringes were sealed with plastecine and a glass capillary tube was use to decant the sample just prior to analysis to fit the analyser. Samples were processed using an ABL 800 blood gas analyser. Results: The mean absolute difference in PO₂ at 10 minutes was -0.94 kPa (95% CI: -1.48 to -0.4 kPa), at 30 minutes -2.42 kPa (95% CI: -3.10 to -1.75 kPa) and at 60 minutes -4.44 kPa (95% CI: -5.54 to -3.34 kPa). The relative difference in pO₂ at 10 minutes was -4.98% (95% CI: -8.12 to -1.84%), at 30 minutes -13.79% (95% CI: -17.40 to -10.17%) and 60 minutes -25.46% (95% CI: -30.97 to -19.95%). The absolute difference in PO₂ at 60 minutes on Ice was - 0.31 kPa. Conclusion: Delayed blood gas analysis in Septic ICU patients with a raised WCC > 12 000/mm³, results in statistical and possible clinical significant abnormality in the pO₂, that progressively worsens with time. After 10 minutes there was a 5% change, at 30 minutes a 14% change and there was a 25% change from baseline PO₂ at 60 minutes. The magnitude of change with statistical mixed linear models shows the rate of decline to be of the magnitude of 1% per minute. So at 60 minutes, the ratio change is 0.7313859 (0.9948 to the power of 60).This deviation may alter clinical decision making. DA - 2017 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2017 T1 - The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis TI - The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis UR - http://hdl.handle.net/11427/26939 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/26939
dc.identifier.vancouvercitationPretorius PR. The influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosis. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Department of Anaesthesia, 2017 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/26939en_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.otherAnaesthesiaen_ZA
dc.titleThe influence of delayed sample processing time on the PO₂ values in critically ill patients with sepsis-induced leukocytosisen_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
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_hsf_2017_pretorius_petrus_rohan.pdf
Size:
1.72 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
Masters