Perioperative use of dexmedetomidine is associated with decreased incidence of ventricular and supraventricular tachyarrhythmias after congenital cardiac operations.

BACKGROUND: Postoperative tachyarrhythmias remain a common complication after congenital cardiac operations. Dexmedetomidine (DEX), an α-2 adrenoreceptor agonist, can have a therapeutic role in supraventricular tachyarrhythmias for cardioversion to sinus rhythm or heart rate control. Whether routine perioperative use of DEX decreases the incidence of supraventricular and ventricular tachyarrhythmias was studied. METHODS: In this prospective cohort study, 32 pediatric patients undergoing cardiothoracic operations received DEX and were compared with 20 control patients who did not receive DEX. RESULTS: Dexmedetomidine was started after anesthesia induction and continued intraoperatively and postoperatively for 38±4 hours (mean dose, 0.76±0.04 µg/kg/h). Ten control patients and 2 DEX patients sustained 16 episodes of tachyarrhythmias (p=0.001), including a 25% vs 0% (p=0.01) incidence of ventricular tachycardia and 25% vs 6% (p=0.05) of supraventricular arrhythmias in the control and DEX group, respectively. Transient complete heart block occurred in 2 control patients and in 1 DEX patient. Control patients had a higher heart rate (141±5 vs 127±3 beats/min, p=0.03), more sinus tachycardia episodes (40% vs 6%; p=0.008), required more antihypertensive drugs with nitroprusside (20±7 vs 4±1 µg/kg; p=0.004) and nicardipine (13±5 vs 2±1 µg/kg; p=0.02), and required more fentanyl (39±8 vs 19±3 µg/kg; p=0.005). CONCLUSIONS: Perioperative use of dexmedetomidine is associated with a significantly decreased incidence of ventricular and supraventricular tachyarrhythmias, without significant adverse effects.

Effect of dexmedetomidine on pulmonary artery pressure after congenital cardiac surgery: A pilot study.

OBJECTIVE: To characterize the effects of dexmedetomidine on the pulmonary artery pressure in patients after congenital cardiac surgery. DESIGN: Prospective observational pilot study. SETTING: Pediatric cardiac intensive care unit at a university hospital. PATIENTS: Twenty-two patients who received dexmedetomidine after cardiothoracic surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: An echocardiogram was performed at three time points: 1) baseline (T0); 2) 6 mins after dexmedetomidine loading (T1); and 3) 1 hr after initiation of dexmedetomidine infusion (T2). Transthoracic echocardiography was used to estimate pulmonary artery pressure based on tricuspid regurgitant velocity (4 x Velocity2) plus central venous pressure. Twenty-two patients aged 0.9 yrs old (interquartile range, 7.9) were enrolled at a median of 1 hr (1.5) after surgery. Dexmedetomidine loading, 0.62 microg/kg (0.5), was given in all patients followed by 0.5 microg/kg/hr (0.6) at T1 and 0.65 microg/kg/hr (0.5) at T2. None of the patients had any increase in pulmonary artery pressure. Overall, the pulmonary artery pressure decreased from 30 mm Hg (13) at T0 to 24 mm Hg (10) at T1 and 26 mm Hg (8) at T2 (p < .001). The pulmonary artery pressure/systemic systolic blood pressure ratio decreased from 33% (12) at T0 to 23% (15) at T1 and 25% (13) at T2 (p = .002). There was no difference in the left ventricular function, Fio2, oxygen %, Po2, CO2, and vasoactive agents. CONCLUSIONS: Administration of dexmedetomidine after congenital cardiac surgery was not associated with any increase in pulmonary artery pressure.

The association of renal dysfunction and the use of aprotinin in patients undergoing congenital cardiac surgery requiring cardiopulmonary bypass.

BACKGROUND: The use of large-dose aprotinin during cardiopulmonary bypass (CPB) in adult patients has been linked to postoperative renal dysfunction, but its effect on the pediatric population undergoing complex congenital cardiac operations is not well defined. METHODS: We used a retrospective cohort analysis to evaluate children undergoing cardiac surgery requiring CPB between July 2004 and July 2006. Demographic data and surgical risk quantified by the Aristotle surgical complexity level were analyzed as covariates. Renal dysfunction was defined according to the RIFLE criteria, an international consensus classification which defines three grades of increasing severity of acute kidney injury: risk (Class R), injury (Class I), and failure (Class F) based on serum creatinine values. A univariate and multivariate logistic regression analysis and a propensity score were used to analyze the data. The propensity score was developed using pretreatment covariates associated with the administration of aprotinin. A multivariate logistic regression was then used with the propensity score and intraoperative measures as covariates. A P value <0.05 was considered statistically significant. RESULTS: Among 395 patients who underwent cardiac surgery, 55% received aprotinin and 45% did not. Thirty-one percent of the cohort had previous cardiac surgery; 17% were neonates. According to the RIFLE criteria, 80 of the patients (20.3%) had acute kidney injury in the postoperative period; 53 (13.4%) had risk of renal dysfunction with 23 (5.8%) having injury and four patients (0.7%) having failure. Those receiving aprotinin had a higher incidence of previous cardiac surgery (54.1% vs 5%), sepsis (6.9% vs. 0.0%), heart failure (24.8% vs 12.4%), mechanical ventilation (25.2% vs 2.8%), or mechanical circulatory support (6.0% vs. 0.6%). More patients had an Aristotle level of 4 (26.6% vs 2.8%) and were treated with diuretics (63.8% vs 26.6%), angiotensin converting enzyme inhibitors (21.1% vs 7.9%), milrinone (25.7% vs 4.5%), and inotropic support (16.1% vs 2.3%). Although there was a significant difference in the unadjusted risk of renal dysfunction, adjustment with the preoperative propensity score revealed that there was no association between aprotinin and renal dysfunction (OR 1.32; 95% CI 0.55-3.19). The duration of CPB was the only independent variable associated with the development of renal dysfunction (OR 1.0; 95% CI 1.009-1.014). CONCLUSIONS: Patients who receive aprotinin are more likely to present with preoperative risk factors for the development of postoperative renal dysfunction. However, when associated risk factors are properly considered, the use of aprotinin does not seem to be associated with a higher risk of developing renal dysfunction in the immediate postoperative period in children.