Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial

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dc.contributor.advisorNtsekhe, Mpiko
dc.contributor.authorKiggundu, Brian
dc.date.accessioned2021-01-27T09:43:40Z
dc.date.available2021-01-27T09:43:40Z
dc.date.issued2020
dc.date.updated2021-01-27T09:43:08Z
dc.description.abstractDiagnosis of infectious pericardial disease has been challenging in the developing world despite improvement of treatment modalities. The diagnostic utility of pH in diagnosing infectious pericardial fluid is unknown, yet this concept is well studied in pleural fluid. This cross-sectional diagnostic study evaluated the diagnostic utility of pH in infectious compared to non-infectious pericardial effusions in a high-burden setting. Methods: Patients of 18 years with moderate to large effusion between the 1st February 2016 and 31st May2018 were enrolled at Groote Schuur Hospital in Cape Town, South Africa. After safe pericardiocentesis, pH was measured with a blood gas analyzer. Mycobacterium tuberculosis culture and/or gene Xpert for TB and/or bacteria culture and/or microscopy served as the reference standard for definite infectious pericardial effusions. We calculated sensitivity, specificity, positive and negative predictive values, negative and positive likelihood ratios for an a priori pH cut off of 7.35. Receiver operating characteristic curve analysis was used for selection of ideal pH cut off. RESULTS Using a set sensitivity of 70% we estimated that we needed to recruit a sample size of 149 subjects for a 95% confidence interval and power of 80%. We screened 200 patients, and excluded 60 because they did not meet the appropriate exclusion criteria. The prevalence of infectious pericarditis was 27.1% (n/N=34/140) as confirmed by the reference standard. We found the median pH (IQR) was 7.30(7.20-7.30) for definite infection, 7.30(7.30-7.35) for probable infection and 7.50(7.40-7.55) for non-infectious effusions p value <0.01 (test for trend). At a cut off or <7.35, the sensitivity was 89.5(95%CI: 75%.5-97.1%) and the specificity was 72.5% (95% CI: 62.8%-80.9%). The ideal ROC- determined cut off for pH that would give maximum sensitivity and specificity was ≤7.30 and the maximum sensitivity and specificity at optimum cut off are 86.8% (95% CI:71.9 - 95.6) and 86.8% (95% CI:71.9 - 95.6), respectively. The area under the curve at this cut-off point is 0.86 (95% CI 0.79 to 0.9), p<0. 001. CONCLUSION: In conclusion, pericardial PH offers diagnostic utility for infectious causes of pericardial effusions using both a PH of 7.35 and an ideal cut-off of 7.30. We recommend that given the simplicity of the test it should be adopted in evaluation of patients with pericardial effusions.
dc.identifier.apacitationKiggundu, B. (2020). <i>Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial</i>. (). ,Faculty of Health Sciences ,Department of Medicine. Retrieved from http://hdl.handle.net/11427/32709en_ZA
dc.identifier.chicagocitationKiggundu, Brian. <i>"Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial."</i> ., ,Faculty of Health Sciences ,Department of Medicine, 2020. http://hdl.handle.net/11427/32709en_ZA
dc.identifier.citationKiggundu, B. 2020. Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial. . ,Faculty of Health Sciences ,Department of Medicine. http://hdl.handle.net/11427/32709en_ZA
dc.identifier.ris TY - Master Thesis AU - Kiggundu, Brian AB - Diagnosis of infectious pericardial disease has been challenging in the developing world despite improvement of treatment modalities. The diagnostic utility of pH in diagnosing infectious pericardial fluid is unknown, yet this concept is well studied in pleural fluid. This cross-sectional diagnostic study evaluated the diagnostic utility of pH in infectious compared to non-infectious pericardial effusions in a high-burden setting. Methods: Patients of 18 years with moderate to large effusion between the 1st February 2016 and 31st May2018 were enrolled at Groote Schuur Hospital in Cape Town, South Africa. After safe pericardiocentesis, pH was measured with a blood gas analyzer. Mycobacterium tuberculosis culture and/or gene Xpert for TB and/or bacteria culture and/or microscopy served as the reference standard for definite infectious pericardial effusions. We calculated sensitivity, specificity, positive and negative predictive values, negative and positive likelihood ratios for an a priori pH cut off of 7.35. Receiver operating characteristic curve analysis was used for selection of ideal pH cut off. RESULTS Using a set sensitivity of 70% we estimated that we needed to recruit a sample size of 149 subjects for a 95% confidence interval and power of 80%. We screened 200 patients, and excluded 60 because they did not meet the appropriate exclusion criteria. The prevalence of infectious pericarditis was 27.1% (n/N=34/140) as confirmed by the reference standard. We found the median pH (IQR) was 7.30(7.20-7.30) for definite infection, 7.30(7.30-7.35) for probable infection and 7.50(7.40-7.55) for non-infectious effusions p value <0.01 (test for trend). At a cut off or <7.35, the sensitivity was 89.5(95%CI: 75%.5-97.1%) and the specificity was 72.5% (95% CI: 62.8%-80.9%). The ideal ROC- determined cut off for pH that would give maximum sensitivity and specificity was ≤7.30 and the maximum sensitivity and specificity at optimum cut off are 86.8% (95% CI:71.9 - 95.6) and 86.8% (95% CI:71.9 - 95.6), respectively. The area under the curve at this cut-off point is 0.86 (95% CI 0.79 to 0.9), p<0. 001. CONCLUSION: In conclusion, pericardial PH offers diagnostic utility for infectious causes of pericardial effusions using both a PH of 7.35 and an ideal cut-off of 7.30. We recommend that given the simplicity of the test it should be adopted in evaluation of patients with pericardial effusions. DA - 2020 DB - OpenUCT DP - University of Cape Town KW - infectious pericardial disease KW - pH KW - Groote Schuur Hospital KW - Cape Town KW - South Africa KW - Mycobacterium tuberculosis culture LK - https://open.uct.ac.za PY - 2020 T1 - Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial TI - Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial UR - http://hdl.handle.net/11427/32709 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/32709
dc.identifier.vancouvercitationKiggundu B. Diagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial. []. ,Faculty of Health Sciences ,Department of Medicine, 2020 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/32709en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Medicine
dc.publisher.facultyFaculty of Health Sciences
dc.subjectinfectious pericardial disease
dc.subjectpH
dc.subjectGroote Schuur Hospital
dc.subjectCape Town
dc.subjectSouth Africa
dc.subjectMycobacterium tuberculosis culture
dc.titleDiagnostic utility of pericardial fluid pH in diagnosing infectious pericardial effusions among patients with moderate and large effusions undergoing pericardiocentesis at Groote Schuur Hospital: a subs-study of the IMPI trial
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMPhil
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