An Elevated Low Cardiac Output Syndrome Score Is Associated With Morbidity in Infants After Congenital Heart Surgery.

OBJECTIVES: To evaluate an empirically derived Low Cardiac Output Syndrome Score as a clinical assessment tool for the presence and severity of Low Cardiac Output Syndrome and to examine its association with clinical outcomes in infants who underwent surgical repair or palliation of congenital heart defects. DESIGN: Prospective observational cohort study. SETTING: Cardiac ICU at Seattle Children's Hospital. PATIENTS: Infants undergoing surgical repair or palliation of congenital heart defects. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Clinical and laboratory data were recorded hourly for the first 24 hours after surgery. A Low Cardiac Output Syndrome Score was calculated by assigning one point for each of the following: tachycardia, oliguria, toe temperature less than 30°C, need for volume administration in excess of 30 mL/kg/d, decreased near infrared spectrometry measurements, hyperlactatemia, and need for vasoactive/inotropes in excess of milrinone at 0.5 µg/kg/min. A cumulative Low Cardiac Output Syndrome Score was determined by summation of Low Cardiac Output Syndrome Score on arrival to cardiac ICU, and 8, 12, and 24 hours postoperatively. Scores were analyzed for association with composite morbidity (prolonged mechanical ventilation, new infection, cardiopulmonary arrest, neurologic event, renal dysfunction, necrotizing enterocolitis, and extracorporeal life support) and resource utilization. Fifty-four patients were included. Overall composite morbidity was 33.3%. Median peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were higher in patients with composite morbidity (3 [2-5] vs 2 [1-3]; p = 0.003 and 8 [5-10] vs 2.5 [1-5]; p < 0.001)]. Area under the receiver operating characteristic curve for cumulative Low Cardiac Output Syndrome Score versus composite morbidity was 0.83, optimal cutoff of greater than 6. Patients with cumulative Low Cardiac Output Syndrome Score greater than or equal to 7 had higher morbidity, longer duration of mechanical ventilation, cardiac ICU, and hospital length of stay (all p ≤ 0.001). After adjusting for other relevant variables, peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were independently associated with composite morbidity (odds ratio, 2.57; 95% CI, 1.12-5.9 and odds ratio, 1.35; 95% CI, 1.09-1.67, respectively). CONCLUSION: Higher peak Low Cardiac Output Syndrome Score and cumulative Low Cardiac Output Syndrome Score were associated with increased morbidity and resource utilization among infants following surgery for congenital heart defects and might be a useful tools in future cardiac intensive care research. Independent validation is required.

A critical appraisal of Vlasselaers D, Milants I, Desmet L, et al: intensive insulin therapy for patients in paediatric intensive care: a prospective, randomised controlled study. Lancet 2009; 373:547-556.

OBJECTIVE: To review findings and discuss implications of strict glycemic control in children. DESIGN: Critical appraisal of a randomized controlled trial. FINDINGS: This is the largest prospective randomized controlled trial to date, comparing intensive insulin therapy (glycemic targets: 50.4-79.2 mg/dL [2.8-4.4 mmol/L] and 70.2-99 mg/dL [3.9-5.5 mmol/L] [for infants and children, respectively]) and conventional insulin therapy (target: 180-215 mg/dl [10-11.9 mmol/L]) among critically ill children. Groups were similar at enrollment and had comparable forms of nutrition and glucose infusion rates. Steroid use and vasoactive-inotrope scores were not compared. Intensive insulin therapy reduced pediatric intensive care unit length of stay (primary outcome measure) and attenuated C-reactive protein concentrations >5 days. The effect of intensive insulin therapy on secondary outcome measures was precise in regards to significant reductions in secondary infection occurrence (absolute risk reduction = 7.6% [95% confidence interval: 0.6-14.4], number needed to treat = 14 [95% confidence interval: 7-179]) and need for vasoactive support beyond 2 days (absolute risk reduction = 10.4% [95% confidence interval: 3-17], number needed to treat = 10 [95% confidence interval: 6-30]). Mortality decreased with intensive insulin therapy (p = .038); however, this finding was imprecise (absolute risk reduction = 3.1% [95% confidence interval: 0.2-5.4], number needed to treat = 33 [95% confidence interval: 18.6-597.3]). The incidence of hypoglycemia was significantly higher with intensive insulin therapy (absolute risk increase = 23.5% [95% confidence interval: 20-25%], number needed to harm = 4 [95% confidence interval: 4-5]). Long-term effects on outcomes were not evaluated, and the authors recognize the need for such follow-up studies. This study demonstrated efficacy of intensive insulin therapy at the same institution where the original adult intensive insulin therapy trial was conducted, but it may not demonstrate effectiveness in populations other than postoperative cardiac patients, which composed the majority of patients enrolled or in institutions without a highly experienced nursing staff to manage intensive insulin therapy. CONCLUSIONS: This was a well-designed single-center trial that serves as proof of concept. The effects of intensive insulin therapy on mortality require further investigation, and its practice may need refinement to reduce the risk of hypoglycemia. In the meantime, targeting age-adjusted fasting glucose ranges cannot be routinely recommended in critically ill children.

Critical illness hyperglycemia in pediatric cardiac surgery.

Critical illness hyperglycemia (CIH) is common in pediatric and adult intensive care units (ICUs). Children undergoing surgical repair or palliation of congenital cardiac defects are particularly at risk for CIH and its occurrence has been associated with increased morbidity and mortality in this population. Strict glycemic control through the use of intensive insulin therapy (IIT) has been shown to improve outcomes in some adult and pediatric studies, yet these findings have sparked controversy. The practice of strict glycemic control has been slow in extending to pediatric ICUs because of the documented increase in the incidence of hypoglycemia in patients treated with IIT. Protocol driven approaches with more liberal glycemic targets have been successfully validated in general and cardiac critical care pediatric patients with low rates of hypoglycemia. It is unknown whether a therapeutic benefit is obtained by keeping patients in this more liberal glycemic control target. Definitive randomized controlled trials of IIT utilizing these targets in critically ill children are ongoing.