Amrinone versus dopamine-nitroglycerin after reconstructive surgery for complete atrioventricular septal defect

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

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.

American College of Critical Care Medicine Clinical Practice Parameters for Hemodynamic Support of Pediatric and Neonatal Septic Shock

OBJECTIVES

The American College of Critical Care Medicine provided 2002 and 2007 guidelines for hemodynamic support of newborn and pediatric septic shock. Provide the 2014 update of the 2007 American College of Critical Care Medicine "Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock."

DESIGN

Society of Critical Care Medicine members were identified from general solicitation at Society of Critical Care Medicine Educational and Scientific Symposia (2006-2014). The PubMed/Medline/Embase literature (2006-14) was searched by the Society of Critical Care Medicine librarian using the keywords: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation, and American College of Critical Care Medicine guidelines in the newborn and pediatric age groups.

MEASUREMENTS AND MAIN RESULTS

The 2002 and 2007 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and American Heart Association/Pediatric Advanced Life Support sanctioned recommendations. The review of new literature highlights two tertiary pediatric centers that implemented quality improvement initiatives to improve early septic shock recognition and first-hour compliance to these guidelines. Improved compliance reduced hospital mortality from 4% to 2%. Analysis of Global Sepsis Initiative data in resource rich developed and developing nations further showed improved hospital mortality with compliance to first-hour and stabilization guideline recommendations.

CONCLUSIONS

The major new recommendation in the 2014 update is consideration of institution-specific use of 1) a "recognition bundle" containing a trigger tool for rapid identification of patients with septic shock, 2) a "resuscitation and stabilization bundle" to help adherence to best practice principles, and 3) a "performance bundle" to identify and overcome perceived barriers to the pursuit of best practice principles.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine

BACKGROUND

The Institute of Medicine calls for the use of clinical guidelines and practice parameters to promote "best practices" and to improve patient outcomes.

OBJECTIVE

2007 update of the 2002 American College of Critical Care Medicine Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock.

PARTICIPANTS

Society of Critical Care Medicine members with special interest in neonatal and pediatric septic shock were identified from general solicitation at the Society of Critical Care Medicine Educational and Scientific Symposia (2001-2006).

METHODS

The Pubmed/MEDLINE literature database (1966-2006) was searched using the keywords and phrases: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation (ECMO), and American College of Critical Care Medicine guidelines. Best practice centers that reported best outcomes were identified and their practices examined as models of care. Using a modified Delphi method, 30 experts graded new literature. Over 30 additional experts then reviewed the updated recommendations. The document was subsequently modified until there was greater than 90% expert consensus.

RESULTS

The 2002 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and AHA sanctioned recommendations. Centers that implemented the 2002 guidelines reported best practice outcomes (hospital mortality 1%-3% in previously healthy, and 7%-10% in chronically ill children). Early use of 2002 guidelines was associated with improved outcome in the community hospital emergency department (number needed to treat = 3.3) and tertiary pediatric intensive care setting (number needed to treat = 3.6); every hour that went by without guideline adherence was associated with a 1.4-fold increased mortality risk. The updated 2007 guidelines continue to recognize an increased likelihood that children with septic shock, compared with adults, require 1) proportionally larger quantities of fluid, 2) inotrope and vasodilator therapies, 3) hydrocortisone for absolute adrenal insufficiency, and 4) ECMO for refractory shock. The major new recommendation in the 2007 update is earlier use of inotrope support through peripheral access until central access is attained.

CONCLUSION

The 2007 update continues to emphasize early use of age-specific therapies to attain time-sensitive goals, specifically recommending 1) first hour fluid resuscitation and inotrope therapy directed to goals of threshold heart rates, normal blood pressure, and capillary refill 70% and cardiac index 3.3-6.0 L/min/m.

Future directions in cardiocerebral resuscitation

Outcomes from pediatric cardiac arrest and cardiopulmonary resuscitation (CPR) seem to be incrementally improving. The past 2 decades have brought advances in the understanding of the pathophysiology of cardiac arrest and ventricular fibrillation, better treatment strategies, and a more robust standard for CPR epidemiology and research reporting. The evolution of practice based on an improved understanding of the pathophysiology and timing, intensity, duration, and variability of the hypoxic-ischemic insult should lead to goal-directed therapy gated to the phase of cardiac arrest and the postarrest period encountered. By strategically focusing therapies to specific phases of cardiac arrest and resuscitation and to the evolving pathophysiology and by implementing evidence-based practice, there is great promise that critical care interventions can lead the way to more successful cardiopulmonary and cerebral resuscitation in children.

Heart failure therapy in children

The most common reason for heart failure in children is volume overload secondary to a left-to-right shunt. Therefore, an accurate diagnosis with identification of possible surgical or interventional reactions should be the first priority. Medical therapy is mainly based on diuretics, angiotensin-converting enzyme inhibitors, cardiac glycosides and beta-blockers. There are few prospective trials in pediatric cardiology, but the available data reach a similar conclusion to that of adults with heart failure. Diuretics are an important tool in patients with fluid retention, and angiotensin-converting enzyme inhibitors are helpful in patients with volume overload of the ventricles. Cardiac glycosides are still in use, but there is a trend toward primary use of diuretics. Angiotensin-converting enzyme inhibitors and beta-blockers have been used successfully in the treatment of heart failure in children, but there are limited data on its efficacy.

Cardiovascular drugs for the newborn

This article reviews the various cardiovascular drugs for newborns, including antiarrhythmics, antihypertensives, inotropes, and pulmonary vasodilators. Antiarrhythmic drugs are classified according to their mechanisms of action, such as effects on ion channels, duration of repolarization, and receptor interaction, which help with understanding the effects of individual antiarrhythmic drugs and selection of drugs for specific arrhythmias. Drug treatment for hypertension should start with a single drug from one of the following classes: ACE inhibitors, angiotensin-receptor antagonists, beta-receptor antagonists, calcium channel blockers, or diuretics. The inotropic drug should be selected according to its specific pharmacologic properties and the specific cardiovascular abnormality to be corrected. An effective pulmonary vasodilator must dilate the pulmonary vasculature more than the systemic vasculature.

Clinical practice parameters for hemodynamic support of pediatric and neonatal patients in septic shock

BACKGROUND

The Institute of Medicine has called for the development of clinical guidelines and practice parameters to develop "best practice" and potentially improve patient outcome.

OBJECTIVE

To provide American College of Critical Care Medicine clinical guidelines for hemodynamic support of neonates and children with septic shock.

SETTING

Individual members of the Society of Critical Care Medicine with special interest in neonatal and pediatric septic shock were identified from literature review and general solicitation at Society of Critical Care Medicine Educational and Scientific Symposia (1998-2001).

METHODS

The MEDLINE literature database was searched with the following age-specific keywords: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, and extracorporeal membrane oxygenation. More than 30 experts graded literature and drafted specific recommendations by using a modified Delphi method. More than 30 more experts then reviewed the compiled recommendations. The task-force chairman modified the document until <10% of experts disagreed with the recommendations.

RESULTS

Only four randomized controlled trials in children with septic shock could be identified. None of these randomized trials led to a change in practice. Clinical practice has been based, for the most part, on physiologic experiments, case series, and cohort studies. Despite relatively low American College of Critical Care Medicine-graded evidence in the pediatric literature, outcomes in children have improved from 97% mortality in the 1960s to 60% in the 1980s and 9% mortality in 1999. U.S. hospital survival was three-fold better in children compared with adults (9% vs. 27% mortality) in 1999. Shock pathophysiology and response to therapies is age specific. For example, cardiac failure is a predominant cause of death in neonates and children, but vascular failure is a predominant cause of death in adults. Inotropes, vasodilators (children), inhaled nitric oxide (neonates), and extracorporeal membrane oxygenation can be more important contributors to survival in the pediatric populations, whereas vasopressors can be more important contributors to adult survival.

CONCLUSION

American College of Critical Care Medicine adult guidelines for hemodynamic support of septic shock have little application to the management of pediatric or neonatal septic shock. Studies are required to determine whether American College of Critical Care Medicine guidelines for hemodynamic support of pediatric and neonatal septic shock will be implemented and associated with improved outcome.

Pharmacokinetics of amrinone in neonates and infants

OBJECTIVE

To evaluate the pharmacokinetics of amrinone and its metabolites in neonates and infants after reconstructive surgery for congenital heart disease.

DESIGN

Prospective study.

SETTING

Pediatric intensive care unit in a university hospital.

PARTICIPANTS

Fifteen neonates aged less than 1 month with transposition of the great arteries and 14 infants aged 2 to 6 months with complete atrioventricular septal defect.

INTERVENTIONS

Amrinone, loading dose of 2 mg/kg, was administered before weaning from cardiopulmonary bypass, followed by a maintenance infusion of 7.5 microg/kg/min.

MEASUREMENTS AND MAIN RESULTS

Blood samples to determine plasma concentrations of amrinone, N-acetylamrinone, and N-glycolylamrinone were drawn before amrinone administration, frequently after the loading dose, every 6 hours during the maintenance infusion, and until 48 hours after the end of the infusion. Amrinone clearance was 2.4 +/- 0.9 mL/kg/min in neonates and 3.2 +/- 1.2 mL/kg/min in infants (p < 0.05). The volume of distribution at steady-state was smaller (p < 0.05) in neonates than in infants. The elimination half-life of amrinone was 10.7 +/- 6.7 hours in neonates and 6.1 +/- 1.4 hours in infants (p < 0.05). There was a linear correlation between the clearance of amrinone and the body surface area (r = 0.67; p < 0.05). The ratio of the plasma concentration of N-acetylamrinone to that of amrinone did not differ between neonates and infants.

CONCLUSIONS

Amrinone is eliminated at a slower rate in neonates than in infants. The rate of acetylation of amrinone appears to be similar; the differences in the elimination capacity of amrinone are mainly due to the immature renal function in neonates.

Amrinone versus dopamine and nitroglycerin in neonates after arterial switch operation for transposition of the great arteries

OBJECTIVE

To compare the efficacy and safety of amrinone and a combination of dopamine and nitroglycerin in neonates after reconstructive surgery for transposition of the great arteries.

DESIGN

A prospective, randomized, double-blind study.

SETTING

Pediatric intensive care unit in a university hospital.

PARTICIPANTS

Thirty-five neonates with transposition of the great arteries.

INTERVENTIONS

A loading dose of amrinone, 2 mg/kg, followed by a maintenance infusion of 7.5 microg/kg/min, were administered to 16 neonates before separation from cardiopulmonary bypass. The remaining 19 patients were administered a combination of dopamine, 5 microg/kg/min, and nitroglycerin, 1 microg/kg/min. An open-label epinephrine infusion was administered in both groups as required.

MEASUREMENTS AND MAIN RESULTS

The circulatory state of the patients was evaluated from 4 to 18 hours after cardiopulmonary bypass. The systemic blood flow index, calculated using the Fick principle, was higher in the amrinone group (1.7+/-0.5 L/min/m2 [mean +/- SD]) compared with the dopamine-nitroglycerin group (1.4+/-0.4 L/min/m2; p < 0.04). The systemic vascular resistance in the amrinone group was lower (26+/-8 Wood units x m2) than in the dopamine-nitroglycerin group (35+/-12 Wood units x m2; p < 0.02). The oxygen extraction ratio was higher in the dopamine-nitroglycerin group (0.34+/-0.08) compared with the amrinone group (0.28+/-0.06; p < 0.02). Lower platelet counts were observed in the amrinone group, but no difference in hemorrhagic complications was seen between the groups.

CONCLUSION

With the dosage regimen used, supplemented with epinephrine, amrinone provides a higher cardiac output and more favorable oxygen dynamics than a combination of dopamine and nitroglycerin.