Care of the pediatric cardiac surgery patient--part 2

A Comparative Analysis of Preemptive Versus Targeted Sedation on Cardiovascular Stability After High-Risk Cardiac Surgery in Infants

OBJECTIVE

To compare the effect of two sedation practices on cardiovascular stability during the early postoperative period in young infants following cardiac surgery: the routine early use of midazolam infusion (preemptive sedation) and the discretionary use of sedatives tailored to the patient's clinical condition (targeted sedation).

DESIGN

Retrospective cohort study with matched controls.

SETTING

A 15-bedded pediatric cardiac ICU.

PATIENTS

Sedation strategies were compared by matching patients before and after the introduction of a targeted sedation guideline, replacing the existing practice of preemptive sedation. Inclusion criteria were age less than 6 months and cardiopulmonary bypass time greater than 150 minutes. Matching criteria were surgical procedure, age, and duration of cardiopulmonary bypass and cross-clamp. The main outcome was cardiovascular instability, defined by the presence of one of the following criteria in the first 12 hours after PICU admission: 1) simultaneous administration of greater than or equal to two inotropic or vasopressor drugs; 2) administration of greater than 60 mL/kg fluid boluses. Secondary outcomes were: 1) markers of cardiac output adequacy (heart rate, blood pressure, vasoactive inotropic score, urine output, volume of fluid boluses, central venous oxygen saturation, lactate); 2) occurrence of adverse events (cardiac arrest, extracorporeal membrane oxygenation, death); 3) sedatives administered and depth of sedation.

INTERVENTIONS

Introduction of a guideline of targeted sedation.

MEASUREMENTS AND MAIN RESULTS

Thirty-three patients with preemptive sedation were matched to 33 patients with targeted sedation. Targeted sedation resulted in less frequent oversedation, without compromising cardiovascular stability, as indicated by similar occurrence of cardiovascular instability (68.8% with preemptive sedation vs 62.5% with targeted sedation; p = 0.53) and adverse events, and similar markers of cardiac output adequacy. Although all preemptively sedated patients received an infusion of midazolam in the first 12 hours after surgery, only 19.4% of patients in the targeted sedation group received a sedative infusion (p < 0.001).

CONCLUSIONS

Our data suggest that after high-risk cardiac surgery in young infants, routine sedation with midazolam may not prevent low cardiac output syndrome. When accompanied by a careful assessment of level of sedation, routine sedation of infants after high-risk cardiac surgery can be avoided without compromising hemodynamic stability or patient safety. The potential benefit of this approach is reduced exposure to sedative.

Early repair of large infant ventricular septal defect despite respiratory syncytial virus-induced respiratory failure with postrepair chylous pericardial effusion requiring pleuropericardial window: a case report and review of the literature

The surgical correction of congenital cardiac lesions that are complicated by intercurrent respiratory syncytial virus (RSV) pneumonitis has traditionally been deferred for at least 6 to 8 weeks. The presumption is that using cardiopulmonary bypass will increase the risk of postoperative pulmonary complications. We present an infant who developed acute respiratory failure related to RSV pneumonitis and required urgent mechanical ventilation. Cardiac evaluation revealed a large nonrestrictive ventricular septal defect (VSD), aortic arch hypoplasia, normally functioning bicuspid aortic valve, and hemodynamic instability associated with markedly increased pulmonary blood flow. Separation from mechanical ventilation was unsuccessful preoperatively. He underwent VSD repair with cardiopulmonary bypass less than 4 weeks after initial RSV infection. He was extubated successfully within 72 hours of VSD repair. Approximately 6 weeks postoperatively, he developed a circumferential chylous pericardial effusion of unclear etiology--an exceedingly rare complication of VSD repair in early infancy in a non-Down syndrome patient. The chylous effusion was initially managed unsuccessfully with Portogen/Monogen and a percutaneously placed pericardial drain. Two weeks later, he underwent creation of a pleuropericardial window with successful resolution of the chylous effusion. It is of interest to pediatricians to be able to correctly time the repair of congenital heart disease lesions after RSV infection to minimize post-bypass pulmonary complications and yet avoid morbidity from undue delays in repair. In addition, chylopericardium can occur in infants after VSD repair, and dietary modification and catheter drainage may not be adequate.