Cardiac power output

Cardiac power output

Cardiac power output (CPO) = (Mean arterial pressure x Cardiac output)/451

Mean arterial pressure = {(Systolic blood pressure − Diastolic blood pressure)/3} + Diastolic blood pressure. This is same as one third of pulse pressure + diastolic pressure.

Cardiac power output is measured in Watts and CPO less than 0.6 W is a poor prognostic indicator. It has been shown to be the strongest hemodynamic correlate of mortality in cardiogenic shock from SHOCK Trial registry [1].

Mendoza et al studied cardiac power output in a broad spectrum of patients with acute cardiac ailment undergoing pulmonary artery catheterization [2]. They had data on 349 patients. Patients with cardiac power out of 0.53 W or less had a significantly higher inhospital mortality.

Tehrani BN et al evaluated standardized team-based care for cardiogenic shock in 204 consecutive patients [3]. They documented that cardiac power output less than 0.6 W was one of the independent predictors of 30 day mortality.

Prognostic value of peak cardiac power output during symptom-limited cardiopulmonary exercise testing in chronic heart failure was studied by Shen Y et al [4]. They found that peak cardiac power out was not a predictor of cardiac mortality in their patients with chronic heart failure. The study involved 129 patients.

Another study evaluated 36 patients undergoing elective coronary artery bypass grafting [5]. They found that cardiac power output was the only systemic hemodynamic variable which remained unaltered in patients with normal ejection fraction. At the same time, stroke work fell significantly in the period of post cardiac surgery stunning.

References

1. Fincke R, Hochman JS, Lowe AM, Menon V, Slater JN, Webb JG, LeJemtel TH, Cotter G; SHOCK Investigators. Cardiac power is the strongest hemodynamic correlate of mortality in cardiogenic shock: a report from the SHOCK trial registry. J Am Coll Cardiol. 2004 Jul 21;44(2):340-8.
2. Mendoza DD, Cooper HA, Panza JA. Cardiac power output predicts mortality across a broad spectrum of patients with acute cardiac disease. Am Heart J. 2007 Mar;153(3):366-70.
3. Tehrani BN, Truesdell AG, Sherwood MW, Desai S, Tran HA, Epps KC, Singh R, Psotka M, Shah P, Cooper LB, Rosner C, Raja A, Barnett SD, Saulino P, deFilippi CR, Gurbel PA, Murphy CE, O’Connor CM. Standardized Team-Based Care for Cardiogenic Shock. J Am Coll Cardiol. 2019 Apr 9;73(13):1659-1669.
4. Shen Y, Song H, Ma W, Gong Z, Ni Y, Zhang X, Xu W, Jiang J, Che L, Xu J, Yan W, Zhou L, Li G, Zhang Q, Wang L. The Prognostic Value of Peak Cardiac Power Output in Chinese Patients with Chronic Heart Failure. PLoS One. 2016 Jan 25;11(1):e0147423.