The Perspective of the Intensivist on Inotropes and Postoperative Care Following Pediatric Heart Surgery: An International Survey and Systematic Review of the Literature

Abstract

Introduction:Inotropes are frequently being used in children undergoing heart surgery to prevent or treat low cardiac output syndrome (LCOS). There is only limited evidence that inotropes actually positively influence postoperative outcome. Our aim was to describe the current international practice variation in the use of inotropes following congenital heart surgery.Methods:We developed an online survey regarding the postoperative use of inotropes. We sent an invitation to all 197 registered members of the Pediatric Cardiac Intensive Care Society (PCICS) to participate in the survey. We also performed a systematic review of the literature.Results:Ninety-eight people (50%) responded, representing 62 international centers. Milrinone is routinely used perioperatively by 90 respondents (97%). Adrenaline/epinephrine is routinely used by 43%, dopamine by 36%, dobutamine by 11%, and levosimendan by 6%. Steroids are used routinely by 54% before initiating cardiopulmonary bypass. Vasopressin is used by 44% of respondents. The development of LCOS is monitored with lactate in 99% of respondents, physical examination (98%), intermittent mixed venous saturation (76%), continuous mixed venous saturation (13%), echocardiography (53%), core–peripheral temperature gap (29%), near-infrared spectrometry (25%), and 4% use cardiac output monitors (PiCCO, USCOM). To improve cardiac output, 42% add/increase milrinone, 37% add adrenaline, and 15% add dopamine. Rescue therapy is titrated individually, based on the patients’ pathophysiology. A systematic review of the literature failed to show compelling evidence with regard to the benefit of inotropes.Conclusions:Despite the lack of sufficient evidence, milrinone is used by the vast majority of caregivers following congenital heart surgery.

Babies and Children at Last

“…Today, the most common perioperative pediatric cardiac output monitoring only uses surrogates such as mixed venous oxygen saturation, lactate concentrations, regional venous oxygen saturation, toe-core temperature difference, and serial echocardiographic exams. 4 Invasive monitoring based on information from arterial and central venous pressures, such as pulse contour analysis methods, have been tested in pediatric patients. However, no study to date has ever tested these systems against a reference method such as the aortic flow probe and many of the devices that are commonly used in adult patients are not yet approved for children (vascular compliance evaluation used to calculate cardiac output with these systems has not been designed for children) by the U.S. Food and Drug Administration.…”

Identification of Time-Dependent Risks of Hemodynamic States After Stage 1 Norwood Palliation

“…6 Simultaneous measures of pressure and oxygen saturation from multiple sites are used to characterize complex circulatory states by application of Ohm's law and the Fick principle during cardiac catheterization, and measurements in both domains are necessary to characterize univentricular circulation. 5,7 Application of this approach through continuous postoperative monitoring with systemic venous oxygen saturation (SvO 2 ) or near-infrared spectroscopic oximetry (NIRS) remains variable in adoption, and physical examination remains a widely used to detect low cardiac output syndrome 8 despite lack of objectivity or validity. 9,10 Univentricular parallel circulation confers multiple mechanisms of impaired systemic oxygen delivery and resulting low SvO 2 .…”

Vasopressin Is No Inotrope

“…However, treating vasoplegia and increasing blood pressure is not the same as increasing cardiac output, which was the focus of our review. 1 The use of vasoactive medication, vasodilators, and vasoconstrictors probably merits a survey and review on its own.…”

“… 2 , 3 In our survey, 79% of respondents indicated they employ a strategy of decreasing afterload in postoperative Norwood patients specifically. 1 It was recently shown in an animal model with fixed loading conditions that milrinone is very poor at increasing cardiac output. 4 My personal belief is that with milrinone, which owes 30% of its increase in cardiac output due to vasodilatation, 5 , 6 we often see hypotension which then requires a vasoactive drug to increase/normalize blood pressure.…”

“…In our survey, 30% of respondents indicated they added norepinephrine for this reason specifically and a total of 55% of respondents indicated the use of norepinephrine and 43% use vasopressin in their prophylactic regimen. 1 Respondents did not specify why a vasoconstrictor was added so frequently, but we assume it was to increase blood pressure as vasopressin has no inotropic properties. The best approach to improve cardiac output is unknown and it still raises many questions.…”