Association between ionised calcium and severity of postpartum haemorrhage: a retrospective cohort study

Authors: Epstein, D., Solomon, N., Korytny, A., Marcusohn, E., Freund, Y., Avrahami, R., Neuberger, A., Raz, A., and Miller, A.

Publication: Br. J. Anaesth; January 2021

Affiliations: Internal Medicine « B » Department, Rambam Health Care Campus, Haifa, Israel Department of Obstetrics and Gynecology, Lis Maternity Hospital, Sourasky Medical Center, Tel Aviv, Israel; Sackler School of Medicine, Tel Aviv University, Ramat-Aviv, Israel ; Department of Gastroenterology, Rambam Health Care Campus, Haifa, Israel; Department of Cardiology, Rambam Health Care Campus, Haifa, Israel ; Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel ; Obstetrics and Gynecology Division, Rambam Health Care Campus, Haifa, Israel

Abstract: BACKGROUND: Postpartum haemorrhage (PPH) is often complicated by impaired coagulation. We aimed to determine whether the level of ionised calcium (Ca (2+)), an essential coagulation co-factor, at diagnosis of PPH is associated with bleeding severity. METHODS: This was a retrospective cohort study of women diagnosed with PPH during vaginal delivery between January 2009 and April 2020. Ca (2+) levels at PPH diagnosis were compared between women who progressed to severe PPH (primary outcome) and those with less severe bleeding. Severe PPH was defined by transfusion of >2 blood units, arterial embolisation or emergency surgery, admission to ICU, or death. Associations between other variables (e.g., fibrinogen concentration) and bleeding severity were also assessed. RESULTS: For 436 patients included in the analysis, hypocalcaemia was more common among patients with severe PPH (51.5% vs 10.6%, P<0.001). In a multivariable logistic regression model, Ca (2+) and fibrinogen were the only parameters independently associated with PPH severity with odds ratios of 1.14 for each 10 mg dl (-1) decrease in fibrinogen (95% confidence interval [CI], 1.05-1.24; P=0.002) and 1.97 for each 0.1 mmol L(-1) decrease in Ca(2+) (95% CI, 1.25-3.1; P=0.003). The performance of Ca (2+) or fibrinogen was not significantly different (area under the curve [AUC]=0.79 [95% CI, 0.75-0.83] vs AUC=0.86 [95% CI, 0.82-0.9]; P=0.09). The addition of Ca (2+) to fibrinogen improved the model, leading to AUC of 0.9 (95% CI, 0.86-0.93), P=0.03. CONCLUSIONS: Ca (2+) level at the time of diagnosis of PPH was associated with risk of severe bleeding. Ca (2+) monitoring may facilitate identification and treatment of high-risk patients.