Hypocalcemia following resuscitation from cardiac arrest revisited

Abstract

Objective Hypocalcemia associated with cardiac arrest has been reported. However, mechanistic hypotheses for the decrease in ionized calcium (iCa) vary and its importance unknown. The objective of this study was to assess the relationships of iCa, pH, base excess (BE), and lactate in two porcine cardiac arrest models, and to determine the effect of exogenous calcium administration on postresuscitation hemodynamics. Methods Swine were instrumented and VF was induced either electrically (EVF, n=65) or spontaneously, ischemically induced (IVF) with balloon occlusion of the LAD (n=37). Animals were resuscitated after 7 minutes of VF. BE, iCa, and pH, were determined prearrest and at 15, 30, 60, 90, 120 min after ROSC. Lactate was also measured in 26 animals in the EVF group. Twelve EVF animals were randomized to receive 1 gm of CaCl2 infused over 20 min after ROSC or normal saline. Results iCa, BE, and pH declined significantly over the 60 min following ROSC, regardless of VF type, with the lowest levels observed at the nadir of left ventricular stroke work post resuscitation. Lactate was strongly correlated with BE (r = −0.89, p<0.0001) and iCa (r= −0.40, p < 0.0001). In a multivariate generalized linear mixed model, iCa was 0.005 mg/dL higher for every one unit increase in BE (95% CI 0.003–0.007, p<0.0001), while controlling for type of induced VF. While there was a univariate correlation between iCa and BE, when BE was included in the regression analysis with lactate, only lactate showed a statistically significant relationship with iCa (p=0.02). Postresuscitation CaCl2 infusion improved post-ROSC hemodynamics when compared to saline infusion (LV stroke work control 8 ± 5 gm-m vs 23 ± 4, p = 0.014, at 30 min) with no significant difference in tau between groups. Conclusions Ionized hypocalcemia occurs following ROSC. CaCl2 improves post-ROSC hemodynamics suggesting that hypocalcemia may play a role in early post-resuscitation myocardial dysfunction.

Association of point‐of‐care blood variables obtained from dogs and cats during cardiopulmonary resuscitation and following return of spontaneous circulation with patient outcomes

“…Ionized hypocalcemia was present in up to 50% of animals undergoing CPR and in up to 42% of animals on first blood sample obtained following ROSC. Ionized hypocalcemia can occur with prolonged CPA and has been shown to correlate with pH 19,74 . Its prevalence in this study was higher and concentrations were lower than previously reported in clinical veterinary patients undergoing CPR, despite a shorter median time to CPR blood sample collection 7 .…”

“…Ionized hypocalcemia can occur with prolonged CPA and has been shown to correlate with pH. 19,74 Its prevalence in this study was higher and concentrations were lower than previously reported in clinical veterinary patients undergoing CPR, despite a shorter median time to CPR blood sample collection. 7 The clinical relevance of this hypocalcemia and potential benefits of medical therapy remain unclear.…”

“…1,[8][9][10][11][12] Common acid-base and electrolyte changes during CPR in experimental animal studies and human patients include metabolic acidosis, hyperlactatemia, hyperkalemia, and ionized hypocalcemia. 1,2,4,5,8,[13][14][15][16][17][18][19][20][21][22][23] Of those, the extent of metabolic acidosis, hyperlactatemia, and hyperkalemia may reflect the duration of CPA and predict the likelihood for return of spontaneous circulation (ROSC) or survival to hospital discharge. 8,9,11,17,23 In critically ill people, the utility of different markers of metabolic acidosis to predict patient outcomes remains controversial.…”

Effect of Intravenous or Intraosseous Calcium vs Saline on Return of Spontaneous Circulation in Adults With Out-of-Hospital Cardiac Arrest

“…Calcium plays an important role in cardiac muscle contraction and is generally acknowledged for its inotropic and vasopressor effects . These effects could be beneficial in the setting of cardiac arrest.…”

Ionized calcium level at emergency department arrival is associated with return of spontaneous circulation in out-of-hospital cardiac arrest

“…Hypocalcemia can induce fatal arrhythmia or cardiac arrest, because calcium is an essential cation in the generation of myocardial action potential resulting in contraction of cardiac muscles and maintenance of vascular tone [ 9 – 11 ]. Therefore, the maintenance of optimal calcium level is important to maintain normal cardiac function and systemic perfusion [ 12 ].…”