Melvin C. Almodovar

Correlation of abdominal site near-infrared spectroscopy with gastric tonometry in infants following surgery for congenital heart disease.

Objective: Splanchnic oximetry, as measured by near-infrared spectroscopy (NIRS), correlates with gastric tonometry as a means of assessing regional (splanchnic) oxygenation and perfusion. Design: Prospective, data-gathering study. Setting: Pediatric cardiac intensive care unit in a tertiary care children’s hospital. Subjects: Neonates and infants with congenital heart disease who underwent catheter intervention or surgical repair requiring cardiopulmonary bypass. Interventions: None. Measurements and Main Results: Twenty neonates and infants were studied within 48 hrs of surgery. We measured somatic saturation (rSO2) via NIRS sensors placed over the anterior abdomen (splanchnic bed) and dorsal lateral flank (renal bed). Somatic rSO2 readings were paired with simultaneous points of intramucosal gastric pH (pHi), measured by tonometry. The rSO2 readings were paired with serum lactate and measurements of systemic mixed venous saturation (S&OV0456;o2). There was strong correlation between the abdominal rSO2 and pHi (r = .79; p < .0001) as well as between abdominal rSO2 and S&OV0456;o2 (r = .89; p < .0001). There was also significant negative correlation between the abdominal rSO2 and serum lactate (r = .77; p < .0001). Correlations between the dorsal lateral (renal) rSO2 measurements and serum lactate and S&OV0456;o2 were also significant but not as strong. Conclusions: Abdominal site rSO2, measured in infants with either single or biventricular physiology, exhibits a strong correlation with gastric pHi as well as with serum lactate and S&OV0456;o2. The results indicate that rSO2 measurements over the anterior abdominal wall correlate more strongly than flank rSO2 with regard to systemic indices of oxygenation and perfusion. This study suggests that the NIRS monitor is a valid modality to obtain an easy, immediate, and noninvasive measurement of splanchnic rSO2 in infants following cardiac surgery for congenital heart disease.

Surgery for coarctation of the aorta in infants weighing less than 2 kg

BACKGROUND Low- and very low-birth weight infants are now candidates for reparative cardiac surgery. Outcomes after coarctation repair have not been characterized in this patient population. METHODS We performed a retrospective review of 18 consecutive neonates less than 2 kg who underwent repair of aortic coarctation between August 1990 and December 1999. RESULTS Median weight was 1,330 g, and median gestational age was 31 weeks. A ventricular septal defect was present in 5 patients, and Shones complex in 4. Sixteen patients had resection and end-to-end anastomosis, and 2 had resection and subclavian flap. Median clamp time was 15.5 minutes. One patient died during hospitalization. Two patients died late postoperatively (5-year estimated survival 80%). Mean follow-up was 28.5 months. Eight patients (44%) had a residual or recurrent coarctation, 5 underwent balloon dilation, and 3 underwent reoperation. Freedom from reintervention for recoarctation was 60% at 5 years. Shones complex or a hypoplastic arch was an independent risk factor for decreased survival (p < 0.001). Very low birth weight was a multivariate predictor for increased risk of recoarctation (p = 0.01). CONCLUSIONS Coarctation repair in less than 2-kg premature non-Shones infants can be performed with a low mortality. The rate of recoarctation is higher in the very low-birth weight infants, but can be managed with low risk.

Extracorporeal membrane oxygenation after stage 1 palliation for hypoplastic left heart syndrome

OBJECTIVE To report the outcomes from a large multicenter cohort of neonates requiring extracorporeal membrane oxygenation (ECMO) after stage 1 palliation for hypoplastic left heart syndrome. METHODS Using data from the Extracorporeal Life Support Organization (2000-2009), we computed the survival to hospital discharge for neonates (age ≤30 days) supported with ECMO after stage 1 palliation for hypoplastic left heart syndrome. The factors associated with mortality were evaluated using multivariate logistic regression analysis. RESULTS Among 738 neonates, the survival rate was 31%. The median age at cannulation was 7 days (interquartile range, 4-11). Black race (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.2-3.6), mechanical ventilation before ECMO (>15-131 hours: OR, 1.6; 95% CI, 1.1-2.4; >131 hours: OR, 1.9; 95% CI, 1.3-2.9), use of positive end expiratory pressure (>6-8 cm H(2)O: OR, 1.7; 95% CI, 1.1-2.7; >8 cm H(2)O: OR, 1.9; 95% CI, 1.2-3.1), and longer ECMO duration (per day, OR, 1.2; 95% CI, 1.1-1.3) increased mortality. ECMO support for failure to wean from cardiopulmonary bypass (OR, 1.6; 95% CI, 1.02-2.4) also decreased survival. ECMO complications, including renal failure (OR, 1.9; 95% CI, 1.2-3.1), inotrope requirement (OR, 1.5; 95% CI, 1.1-2.1), myocardial stun (OR, 3.2; 95% CI, 1.3-7.7), metabolic acidosis (OR, 2.9; 95% CI, 1.3-6.7), and neurologic injury (OR, 1.7; 95% CI, 1.1-2.6), during support also increased mortality. CONCLUSIONS Mortality for neonates with hypoplastic left heart syndrome supported with ECMO after stage 1 palliation is high. Longer ventilation before cannulation, longer support duration, and ECMO complications increased mortality.

Extracorporeal membrane oxygenation for the support of adults with acute myocarditis.

Objectives: To characterize survival outcomes for adult patients with acute myocarditis supported with extracorporeal membrane oxygenation and identify risk factors for in-hospital mortality. Design: Retrospective review of Extracorporeal Life Support Organization registry database. Setting: Data reported to Extracorporeal Life Support Organization by 230 extracorporeal membrane oxygenation centers. Patients: Patients 16 years old or older supported with extracorporeal membrane oxygenation for myocarditis during 1995 to 2011. Interventions: None. Measurements and Main Results: There were 150 separate runs of extracorporeal membrane oxygenation for 147 patients with a diagnosis of acute myocarditis in the Extracorporeal Life Support Organization database from 1995 through 2011. Survival to hospital discharge was 61%. Nine patients underwent heart transplantation, and transplant-free survival to discharge was 56%. Extracorporeal membrane oxygenation was deployed during extracorporeal cardiopulmonary resuscitation in 31 patients (21% of the cohort). In a multivariate model evaluating pre–extracorporeal membrane oxygenation and extracorporeal membrane oxygenation support factors, pre–extracorporeal membrane oxygenation arrest (adjusted odds ratio, 2.4; 95% CI, 1.1–5.0) and need for higher extracorporeal membrane oxygenation flows at 4 hours post–extracorporeal membrane oxygenation cannulation (odds ratio, 2.8; 95% CI, 1.1–7.3) were associated with increased odds of in-hospital mortality. In a second multivariate model evaluating adverse events while on extracorporeal membrane oxygenation, central nervous system injury (odds ratio, 26.5; 95% CI, 7.3–96.6), renal failure (odds ratio, 3.6; 95% CI, 1.4–9.3), arrhythmia (odds ratio, 5.8; 95% CI, 2.2–15.1), and hyperbilirubinemia (odds ratio, 9.1; 95% CI, 2.6–31.8) were associated with increased odds of in-hospital mortality. Conclusions: Extracorporeal membrane oxygenation can be used effectively in adults with myocarditis to support the circulation while awaiting myocardial recovery. Early extracorporeal membrane oxygenation deployment prior to cardiac arrest may be associated with better outcomes.

Anesthesia considerations for children with pulmonary hypertension

Children with pulmonary arterial hypertension undergoing anesthesia pose a challenge. The prevalence of morbidity and mortality in this subgroup is substantially greater than that in the general population. In this article, we attempt to describe the adverse events that occur and also identify some of the factors that may precipitate them. We also suggest mechanisms to attenuate or prevent these crises.

Extracorporeal membrane oxygenation-supported cardiopulmonary resuscitation following stage 1 palliation for hypoplastic left heart syndrome.

Objectives: To report on survival from a large multicenter cohort of neonates with hypoplastic left heart syndrome requiring extracorporeal membrane oxygenation–assisted cardiopulmonary resuscitation after stage 1 palliation operation. Design: Retrospective analysis of data from the Extracorporeal Life Support Organization data registry (1998 through 2013). We computed the survival to hospital discharge for neonates (age < 30 d) who required extracorporeal membrane oxygenation after stage 1 palliation and evaluated factors associated with mortality using multivariate logistic regression analysis. Setting: Multicenter data reported to Extracorporeal Life Support Organization registry. Patients: Infants with hypoplastic left heart syndrome after stage 1 palliation who received extracorporeal membrane oxygenation–assisted cardiopulmonary resuscitation. Interventions: None. Measurements and Main Results: There were 307 extracorporeal membrane oxygenation runs in the setting of extracorporeal membrane oxygenation–assisted cardiopulmonary resuscitation in 293 neonates with hypoplastic left heart syndrome following stage 1 palliation operation. The median age at cannulation was 9 days (interquartile range, 5–14 d). Survival to hospital discharge was 36%. In univariate analysis, gestational age, weight, extracorporeal membrane oxygenation duration, presence of air embolism, hemorrhagic complications, renal failure, and pulmonary complications (pulmonary hemorrhage and pneumothorax) were all associated with nonsurvival. In multivariate analysis, lower body weight at cannulation (odds ratio, 3.9; 95% CI, 1.9–8.3), duration of the extracorporeal membrane oxygenation (odds ratio, 3.4; 95% CI, 1.9–7.3), and renal failure while on extracorporeal membrane oxygenation (odds ratio, 2; 95% CI, 1.2–3.5) increased odds of mortality. Conclusions: Mortality for neonates with hypoplastic left heart syndrome supported with extracorporeal membrane oxygenation–assisted cardiopulmonary resuscitation after stage 1 palliation is high. Lower body weight, increased duration of extracorporeal membrane oxygenation support, and renal failure increased mortality.

Factors Associated With Mortality in Neonates Requiring Extracorporeal Membrane Oxygenation for Cardiac Indications: Analysis of the Extracorporeal Life Support Organization Registry Data*

Objectives: Survival among neonates supported with extracorporeal membrane oxygenation for cardiac indications is 39%. Previous single-center studies have identified factors associated with mortality, but a comprehensive multivariate analysis is not available for this population. Understanding factors associated with mortality may help design treatment strategies, determine optimal timing for cannulation, and inform patient selection. This study identifies factors associated with mortality in neonates supported with extracorporeal membrane oxygenation for cardiac indications. Design: Retrospective cohort study. Setting: Two hundred and thirty U.S. and international centers reporting extracorporeal membrane oxygenation data to the Extracorporeal Life Support Organization. Subjects: Four thousand and four seventy one neonates with congenital and acquired cardiac disease supported with extracorporeal membrane oxygenation for cardiac indications during 2001–2011. Interventions: None. Measurements and Results: The primary outcome measure was mortality prior to hospital discharge. Overall hospital mortality was 59%. Demographic and preextracorporeal membrane oxygenation factors associated with mortality were evaluated in a multivariable model. Factors associated with death prior to hospital discharge included lower body weight, earlier era, single ventricle physiology, lower preextracorporeal membrane oxygenation arterial pH, and longer time from intubation to extracorporeal membrane oxygenation cannulation. Lower pH was associated with increased mortality regardless of cardiac diagnosis and surgical complexity. The majority of survivors separated from extracorporeal membrane oxygenation less than 8 days after extracorporeal membrane oxygenation deployment. Conclusions: Mortality for neonates supported with extracorporeal membrane oxygenation for cardiac indications is high. Severity of preextracorporeal membrane oxygenation acidosis was independently associated with increased risk of mortality. Earlier initiation of extracorporeal membrane oxygenation may reduce the degree and duration of acidosis and may improve survival. Further studies are needed to determine optimal timing of cannulation in this population.

Femoral artery catheterization in neonates and infants

Objective: To determine the incidence of perfusion-related complications associated with indwelling femoral artery monitoring catheters in neonates and infants following introduction of a 2.5-F diameter, 5-cm length, polyethylene catheter (Cook Medical, Bloomington, IN) to our unit. Design: Prospective observational cohort study. Setting: Pediatric cardiac intensive care unit in a university-affiliated childrens hospital. Patients: All patients <2 yrs old with an indwelling femoral artery catheter during a 3-yr period. Interventions: None. Measurements and Main Results: Two hundred eighty-two patients (including 98 neonates), median (range) age 10 wks (0.1–84), weight 4.1 kg (2.0–11.1) were enrolled; outcomes in 249 were evaluable. Pulse strength in dorsalis pedis arteries and pulse discrepancies between feet were assessed hourly by the cardiac intensive care unit nurse and recorded on a flow sheet. Nonpalpable pulses were assessed as “absent” or “present” with ultrasonic Doppler. Following removal of the catheter, assessments of pulse strength continued until resolution of any discrepancies. Median (range) duration of catheterization was 4 days (1–23). Catheters of 2.5-F diameter were used in 227 patients and larger catheters in 55 patients. The incidence of pulse strength discrepancies between feet was 20%, loss of pulse was 3.4% (6.7% in neonates, 1.4% in older infants) when extracorporeal membrane oxygenation patients were excluded, and resolution of pulse discrepancy or loss was 100%. Duration of catheterization and use of a catheter larger than 2.5 Fr were significant predictors of loss of pulse. Conclusions: Loss of pedal pulse distal to small-bore monitoring femoral artery catheters in neonates and infants is directly related to the duration of catheterization and is less frequent when 2.5-F, 5-cm polyethylene catheters are used instead of larger catheters.

Task Force 5: Pediatric Cardiology Fellowship Training in Critical Care Cardiology

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Phosphodiesterase Inhibitor‐Based Vasodilation Improves Oxygen Delivery and Clinical Outcomes Following Stage 1 Palliation

Background Systemic vasodilation using α‐receptor blockade has been shown to decrease the incidence of postoperative cardiac arrest following stage 1 palliation (S1P), primarily when utilizing the modified Blalock‐Taussig shunt. We studied the effects of a protocol in which milrinone was primarily used to lower systemic vascular resistance (SVR) following S1P using the right ventricular to pulmonary artery shunt, measuring its effects on oxygen delivery (DO 2) profiles and clinical outcomes. We also correlated Fick‐based assessments of DO 2 with commonly used surrogate measures. Methods and Results Neonates undergoing S1P were treated according to best clinical judgment prior to (n=32) and following (n=24) implementation of a protocol that guided operative, anesthetic, and postoperative management, particularly as it related to SVR. A majority of the subjects (n=51) received a modified right ventricular to pulmonary artery shunt. In a subset of these patients (n=21), oxygen consumption (VO 2) was measured and used to calculate SVR, DO 2, and oxygen debt. Neonates treated with the protocol had significantly lower SVR (P=0.02), serum lactate (P<0.001), and Sa‐vO 2 difference (P<0.001) and a lower incidence of CPR requiring extracorporeal membrane oxygenation (E‐CPR, P=0.02) within the first 72 postoperative hours. DO 2 was closely associated with SVR (r2=0.78) but correlated poorly with arterial (SaO2) and venous (SvO2) oxyhemoglobin concentrations, the Sa‐vO 2 difference, and blood pressure. Conclusions A vasodilator protocol utilizing milrinone following S1P effectively decreased SVR, improved serum lactate, and decreased postoperative cardiac arrest. DO 2 correlated more closely with SVR than with Sa‐vO 2 difference, highlighting the importance of measuring VO 2 in this population. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02184169.