Relationship of ECMO duration with outcomes after pediatric cardiac surgery: a multi-institutional analysis

BACKGROUND

There are very sparse data on the outcomes of children receiving prolonged extracorporeal membrane oxygenation (ECMO) after cardiac surgery. This study was aimed to evaluate the association of ECMO duration with outcomes in children undergoing surgery for congenital heart disease using the Pediatric Health Information System (PHIS) database.

METHODS

Patients aged ≤18 years receiving ECMO after pediatric cardiac surgery (with or without cardiopulmonary bypass) at a PHIS-participating hospital (2004-2013) were included. De-identified data obtained from retrospective, observational dataset included demographic information, baseline characteristics, pre-ECMO risk factors, operation details, patient diagnoses, and center data. Outcomes evaluated included in-hospital mortality, length of mechanical ventilation, length of ICU stay, length of hospital stay, and hospital charges. Cox proportional hazards models were fitted to study the probability of study outcomes as a function of ECMO duration.

RESULTS

Nine hundred ninety-eight patients from 37 hospitals qualified for inclusion. The median duration of ECMO run was 4 days (IQR: 1.7). After adjusting for patient and center characteristics, there was 12% increase in the odds of mortality for every 24 hours increase in ECMO duration (OR: 1.12, 95% CI: 1.07-1.18, P<0.001). Patients receiving longer duration of ECMO were associated with longer length of mechanical ventilation, longer length of ICU stay, longer length of hospital stay, and higher hospital charges.

CONCLUSION

Data from this large multicenter database suggest that longer duration of ECMO support after pediatric cardiac surgery is associated with worsening outcomes.

Association of presence and timing of invasive airway placement with outcomes after pediatric in-hospital cardiac arrest

BACKGROUND

Little data exist regarding the association of presence of an invasive airway before cardiac arrest or early placement of an invasive airway after cardiac arrest with outcomes in children who experience in-hospital cardiac arrest.

METHODS

We conducted a retrospective review of patients aged 1 day to 18 years who received cardiopulmonary resuscitation (CPR) for ≥ 1 min in any of the three intensive care units (ICUs) at a tertiary care, academic children's hospital between 2002 and 2010. Specific outcomes evaluated included survival to hospital discharge, return of spontaneous circulation (ROSC), 24-h survival, and good neurological status at hospital discharge. We fitted multivariable logistic regression models to evaluate the association between the presence of an invasive airway prior to cardiac arrest and timing of placement of an invasive airway with these outcomes.

RESULTS

Three hundred and ninety-one patients were included. Of these, 197 (51%) patients were already tracheally intubated before the occurrence of cardiac arrest. Median time to intubation was 6 min [interquartile range (IQR): 2, 12] among the 194 patients tracheally intubated following cardiac arrest. We found lower survival to hospital discharge among patients intubated prior to cardiac arrest (intubated vs. non-intubated group, 43% vs. 61%, p < 0.001). After adjusting for patient and event characteristics, presence of an invasive airway prior to cardiac arrest was not associated with a significant improvement in survival to hospital discharge [odds ratio (OR): 0.70, 95% confidence interval (CI): 0.42-1.16, p = 0.17], or good neurological outcomes (OR: 0.60, 95% CI: 0.34-1.05, p = 0.07). Similarly, early placement of an invasive airway after cardiac arrest was also not associated with an improvement in survival to hospital discharge (OR: 1.05, 95% CI: 0.78-1.42, p = 0.73), or good neurological outcomes (OR: 1.08, 95% CI: 0.77-1.53, p = 0.65).

CONCLUSIONS

Our study demonstrates that presence of an invasive airway prior to cardiac arrest or early placement of an invasive airway after cardiac arrest is not associated with an improvement in survival to hospital discharge or good neurological outcomes. Further study of the relationship between invasive airway management and survival following cardiac arrest is warranted.

Extracorporeal membrane oxygenation in children with heart disease and del22q11 syndrome: a review of the Extracorporeal Life Support Organization Registry

The study objective was to evaluate outcomes among children with del22q11 (DiGeorge) syndrome supported on ECMO for heart disease. The ELSO registry database was queried to include all children <18 years undergoing heart surgery for either common atrio-ventricular canal, tetralogy of Fallot, truncus arteriosus or transposition of the great vessels and interrupted aortic arch and requiring ECMO, from 1998-2011. The outcomes evaluated included mortality, ECMO duration and length of hospital stay in patients with del22q11 syndrome and with no del22q11 syndrome. Eighty-eight ECMO runs occurred in children with del22q11 syndrome while 2694 ECMO runs occurred in children without del22q11 syndrome. For patients with heart defects receiving ECMO, del22q11 syndrome did not confer a significant mortality risk or an increased risk of infectious complications before or while on ECMO support. Neither the duration of ECMO nor mechanical ventilation prior to ECMO deployment were prolonged in patients with del22q11 syndrome compared to the controls.

Longitudinal renal function in pediatric heart transplant recipients: 20-years experience

This study was initiated to assess the temporal trends of renal function, and define risk factors associated with worsening renal function in pediatric heart transplant recipients in the immediate post-operative period. We performed a single-center retrospective study in children ≤18 yr receiving OHT (1993-2012). The AKIN's validated, three-tiered AKI staging system was used to categorize the degree of WRF. One hundred sixty-four patients qualified for inclusion. Forty-seven patients (28%) were classified as having WRF after OHT. Nineteen patients (11%) required dialysis after heart transplantation. There was a sustained and steady improvement in renal function in children following heart transplantation in all age groups, irrespective of underlying disease process. The significant factors associated with risk of WRF included body surface area (OR: 1.89 for 0.5 unit increase, 95% CI: 1.29-2.76, p = 0.001) and use of ECMO prior to and/or after heart transplantation (OR: 3.50, 95% CI: 1.51-8.13, p = 0.004). Use of VAD prior to heart transplantation was not associated with WRF (OR: 0.50, 95% CI: 0.17-1.51, p = 0.22). On the basis of these data, we demonstrate that worsening renal function improves early after orthotopic heart transplantation.

Variation of ventilation practices with center volume after pediatric heart surgery

BACKGROUND

This study was designed to evaluate the odds of mechanical ventilation and duration of mechanical ventilation after pediatric cardiac surgery across centers of varying center volume using the Virtual PICU Systems database.

HYPOTHESIS

Children receiving cardiac surgery at high-volume centers will be associated with lower odds of mechanical ventilation and shorter duration of mechanical ventilation, compared with low-volume centers.

METHODS

Patients age <18 years undergoing operations (with or without cardiopulmonary bypass) for congenital heart disease at one of the participating intensive care units in the Virtual PICU Systems database were included (2009-2013). Logistic regression models and Cox proportional hazards models were fitted for the probability of conventional mechanical ventilation and duration of mechanical ventilation, respectively, to investigate the difference in the outcomes between different center volume groups with/without adjustment for other risk factors.

RESULTS

A total of 10 378 patients from 43 centers qualified for inclusion. Of these, 7648 (74%) patients received conventional mechanical ventilation after cardiac surgery. Higher center volume was significantly associated with lower odds of mechanical ventilation after cardiac surgery (odds ratio: 2.68, 95% confidence interval: 2.15-3.35). However, patients receiving mechanical ventilation in these centers were associated with longer duration of mechanical ventilation, compared with lower-volume centers (hazard ratio: 1.26, 95% confidence interval: 1.16-1.37). This association was most prominent in the lower surgical-risk categories.

CONCLUSIONS

Large clinical practice variations were demonstrated for mechanical ventilation following pediatric cardiac surgery among intensive care units of varied center volumes.

Incidence, predictors, and outcomes of extubation failure in children after orthotopic heart transplantation: a single-center experience

The objective of this study is to describe the incidence, etiologies, predictors, and outcomes of extubation failure in children undergoing orthotopic heart transplantation (OHT). A Retrospective, observational study was designed to evaluate clinical outcomes. . The study was conducted in a cardiovascular intensive care unit (CVICU) setting at a single, tertiary care, academic children's hospital. We collected demographic, pre-operative, intra-operative, post-operative and peri-extubation data in a retrospective, observational format from patients who underwent OHT at our institution. Clinical outcomes evaluated included the success or failure of extubation, CVICU length of stay (LOS), hospital LOS, and in-hospital mortality. We utilized descriptive and univariate statistics to compare the group with extubation failure to the group with extubation success. There were no interventions in this study. During the study period, 127 patients qualified for inclusion. The median age of patients was 108 months [interquartile range (IQR): 25-169] and median weight was 23 kg (IQR: 10.6-48). Extubation failure occurred in 12.5 % (16/127) of the patients. Median duration of mechanical ventilation was 2 days (IQR: 1-4.5), median CVICU LOS was 7 days (IQR: 5-13), and the median hospital LOS was 36 days (IQR: 20-74). Overall in-hospital mortality was 2 % (2/127). There was a significant improvement in blood pressure (p < 0.001) with a decrease in inotropic score (p < 0.001) after removal of positive pressure ventilation among the patients with extubation success. Independent factors associated with extubation failure included lower body weight, need for mechanical ventilation prior to heart transplantation, renal failure prior to extubation attempt, and right ventricular diastolic dysfunction prior to extubation attempt. Our study demonstrates that extubation failure in patients after OHT is infrequent and the causes are diverse. Extubation success in children after OHT is associated with improvement in mean arterial blood pressure, decrease in inotropic support, and decrease in supplemental oxygen requirement.

β-Blockers and angiotensin converting enzyme inhibitors: comparison of effects on aortic growth in pediatric patients with Marfan syndrome

OBJECTIVES

Angiotensin converting enzyme inhibitors (ACEI) have been shown to decrease aortic growth velocity (AGV) in Marfan syndrome (MFS). We sought to compare the effect of β-blockers and ACEI on AGV in MFS.

STUDY DESIGN

We retrospectively reviewed all data from all patients with MFS seen at Arkansas Children's Hospital between January 1, 1976 and January 1, 2013. Generalized least squares were used to evaluate AGV over time as a function of age, medication group, and the interaction between the 2. A mixed model was used to compare AGV between medication groups as a function of age, medication group (none, β-blocker, ACEI), and the interaction between the 2.

RESULTS

A total of 67 patients with confirmed MFS were identified (34/67, 51% female). Mean age at first encounter was 13 ± 10 years, with mean follow-up of 7.6 ± 5.8 years. There were 839 patient encounters with a median of 10 (range 2-42) encounters per patient. AGV was nearly normal in the β-blocker group, and was less than either the ACEI or untreated groups. The AGV was higher than normal in ACEI and untreated groups (P < .001 for both).

CONCLUSIONS

β-blocker therapy results in near-normalization of AGV in MFS. ACEI did not decrease AGV in a clinically significant manner.

Relationship between renal function and extracorporeal membrane oxygenation use: a single-center experience

The effects of extracorporeal membrane oxygenation (ECMO) support on renal function in children with critical illness are unknown. The objective of this study was to investigate the impact of ECMO on renal function among children in different age groups. We performed a single-center retrospective observational study in critically ill children ≤ 18 years supported on ECMO for refractory cardiac or pulmonary failure (2006-2012). The patient population was divided into four age groups for the purpose of comparisons. The Acute Kidney Injury Network's (AKIN's) validated, three-tiered staging system for acute kidney injury was used to categorize the degree of worsening renal function. Data on patient demographics, baseline characteristics, renal function parameters, dialysis, ultrafiltration, duration of mechanical cardiac support, and mortality were collected. Comparisons of baseline characteristics, duration of mechanical cardiac support, and renal function were made between the four age groups. During the study period, 311 patients qualified for inclusion, of whom 289 patients (94%) received venoarterial (VA) ECMO, 12 (4%) received venovenous (VV) ECMO, and 8 (3%) received both VV and VA ECMO. A total of 109 patients (36%) received ultrafiltration on ECMO, 58 (19%) received hemodialysis, and 51 (16%) received peritoneal dialysis. There was a steady and sustained improvement in renal function in all age groups during the ECMO run, with the maximum and longest-sustained improvement occurring in the oldest age group. Proportions of patients in different AKIN stages remained similar in the first 7 days after ECMO initiation. We demonstrate that renal dysfunction improves early after ECMO support. Irrespective of the underlying disease process or patient age, renal function improves in children with pulmonary or cardiac failure who are placed on ECMO.

Association of center volume with outcomes in critically ill children with acute asthma

BACKGROUND

Little is known about the relation between center volume and outcomes in children requiring intensive care unit (ICU) admission for acute asthma.

OBJECTIVE

To evaluate the association of center volume with the odds of receiving positive pressure ventilation and length of ICU stay.

METHODS

Patients 2 to 18 years of age with the primary diagnosis of asthma were included (2009-2012). Center volume was defined as the average number of mechanical ventilator cases per year for any diagnoses during the study period. In multivariable analysis, the odds of receiving positive pressure ventilation (invasive and noninvasive ventilation) and ICU length of stay were evaluated as a function of center volume.

RESULTS

Fifteen thousand eighty-three patients from 103 pediatric ICUs with the primary diagnosis of acute asthma met the inclusion criteria. Seven hundred fifty-two patients (5%) received conventional mechanical ventilation and 964 patients (6%) received noninvasive ventilation. In multivariable analysis, center volume was not associated with the odds of receiving any form of positive pressure ventilation in children with acute asthma, with the exception of high- to medium-volume centers. However, ICU length of stay varied with center volume and was noted to be longer in low-volume centers compared with medium- and high-volume centers.

CONCLUSION

In children with acute asthma, this study establishes a relation between center volume and ICU length of stay. However, this study fails to show any significant relation between center volume and the odds of receiving positive pressure ventilation; further analyses are needed to evaluate this relation in more detail.

Comparison of high-frequency oscillatory ventilation and conventional mechanical ventilation in pediatric respiratory failure

IMPORTANCE

Outcomes associated with use of high-frequency oscillatory ventilation (HFOV) in children with acute respiratory failure have not been established.

OBJECTIVE

To compare the outcomes of HFOV with those of conventional mechanical ventilation (CMV) in children with acute respiratory failure.

DESIGN, SETTING, AND PARTICIPANTS

We performed a retrospective, observational study using deidentified data obtained from all consecutive patients receiving mechanical ventilation aged 1 month to 18 years in the Virtual PICU System database from January 1, 2009, through December 31, 2011. The study population was divided into 2 groups: HFOV and CMV. The HFOV group was further divided into early and late HFOV. Propensity score matching was performed as a 1-to-1 match of HFOV and CMV patients. A similar matching process was performed for early HFOV and CMV patients.

EXPOSURE

High-frequency oscillatory ventilation.

MAIN OUTCOMES AND MEASURES

Length of mechanical ventilation, intensive care unit (ICU) length of stay, ICU mortality, and standardized mortality ratio (SMR).

RESULTS

A total of 9177 patients from 98 hospitals qualified for inclusion. Of these, 902 (9.8%) received HFOV, whereas 8275 (90.2%) received CMV. A total of 1764 patients were matched to compare HFOV and CMV, whereas 942 patients were matched to compare early HFOV and CMV. Length of mechanical ventilation (CMV vs HFOV: 14.6 vs 20.3 days, P < .001; CMV vs early HFOV: 14.6 vs 15.9 days, P < .001), ICU length of stay (19.1 vs 24.9 days, P < .001; 19.3 vs 19.5 days, P = .03), and mortality (8.4% vs 17.3%, P < .001; 8.3% vs 18.1%, P < .001) were significantly higher in HFOV and early HFOV patients compared with CMV patients. The SMR in the HFOV group was 2.00 (95% CI, 1.71-2.35) compared with an SMR in the CMV group of 0.85 (95% CI, 0.68-1.07). The SMR in the early HFOV group was 1.62 (95% CI, 1.31-2.01) compared with an SMR in the CMV group of 0.76 (95% CI, 0.62-1.16).

CONCLUSIONS AND RELEVANCE

Application of HFOV and early HFOV compared with CMV in children with acute respiratory failure is associated with worse outcomes. The results of our study are similar to recently published studies in adults comparing these 2 modalities of ventilation for acute respiratory distress syndrome.

Comparative effects of ventricular assist device and extracorporeal membrane oxygenation on renal function in pediatric heart failure

BACKGROUND

Effects of mechanical cardiac support on renal function in children with end-stage heart failure are unknown. The objective of this study was to investigate the impact of ventricular assist device (VAD) and extracorporeal membrane oxygenation (ECMO) on renal function in children.

METHODS

We performed a single center retrospective observational study in children with end-stage heart failure supported on pediatric mechanical cardiac support. The patient population was divided into three groups: the VAD group included patients receiving ventricular assist device support; the ECMO group included patients receiving extracorporeal membrane oxygenation membrane support for more than 14 days; and the ECMO+VAD group included patients receiving ECMO followed by VAD support. Comparison of baseline characteristics, duration of mechanical cardiac support, and renal function was made between the three groups.

RESULTS

During the study period, there were 23 patients in the VAD group, 16 patients in the ECMO+VAD group, and 37 patients in the ECMO group. The patients in the ECMO group were significantly younger and smaller than the patients in the VAD and ECMO+VAD groups. There was a steady improvement in eGFR in the VAD group and the ECMO+VAD group until day 7 after which there was a decline in renal function. In the ECMO group, the improvement in eGFR continued until day 28 after which there was a steady decline in eGFR. Improvement in eGFR in the VAD group and the ECMO+VAD group was much higher than in the ECMO group in the first 7 days.

CONCLUSIONS

On the basis of these data, we demonstrate that renal dysfunction improves early after mechanical cardiac support.

Characteristics and hemodynamic effects of extubation failure in children undergoing complete repair for tetralogy of Fallot

This study aimed to identify the prevalence, etiology, and outcomes of extubation failure in children after complete repair for tetralogy of Fallot at a single tertiary-care, academic children's hospital. The secondary aim of this study was to determine the cardiorespiratory effects of the transition from positive-pressure ventilation to spontaneous breathing in children with extubation success and extubation failure. For this study, extubation was defined as the need for reintubation within 96 h after extubation. Demographics as well as pre-, intra-, post-, and periextubation data were collected in a retrospective observational format for patients who underwent complete repair for tetralogy of Fallot during the period January 2001-June 2011. Patients with multiple aortopulmonary collateral arteries or associated complete atrioventricular septal defects were excluded from the study. The cardiorespiratory variables collected before and immediately after extubation included heart rate, respiratory rate, mean arterial blood pressure, central venous pressures, near-infrared spectroscopy, oxygen saturations, and lactate levels. The clinical outcomes evaluated included the success or failure of extubation and the hospital length of stay. Descriptive and univariate statistics were used to compare the group with extubation failure and the group with extubation success. Extubation failure occurred for 7 % (12/164) of the 164 eligible patients during the study period. The median age of the patients at surgery was 200 days (range 98-356 days), and their median weight was 6.8 kg (range 5.2-8.5 kg). For 6 % (10/164) of the patients, intubation was performed before surgery. The median duration of mechanical ventilation was 33 h (range 19.5-73 h), and the median hospital stay was 10 days (range 7-15 days). Of the 12 patients with extubation failure, 2 had extubation failure in first 2 h after extubation, 6 had failure in 2-24 h, 3 had failure in 24-48 h, and 1 had failure in 48-96 h. The patients in the extubation success and extubation failure groups were similar in age, sex, and body weight at the time of surgery. All preexisting conditions also were similar in the two groups. The intraoperative variables and postoperative complications did not differ between the two groups. The hospital stay was longer for the children with extubation failure (p < 0.001). The partial pressure of oxygen in arterial blood (PaO2), tachycardia, mean arterial blood pressure, and inotrope score improved significantly at conversion from positive-pressure ventilation to spontaneous ventilation in the patients with extubation success. This study demonstrated that extubation failure in patients after complete repair for tetralogy of Fallot is low and that the etiology is diverse. The majority of extubation failures in these patients occurred in the first 24 h. Extubation success in the children after repair for tetralogy of Fallot was associated with improvement in PaO2, tachycardia, and mean arterial pressure, with a decrease in inotrope score. Extubation failure is associated with a longer hospital stay.

Timing of complete repair of non-ductal-dependent tetralogy of Fallot and short-term postoperative outcomes, a multicenter analysis

OBJECTIVE

There is cross-center variability with regard to timing repair of non-ductal-dependent tetralogy of Fallot (TOF). We hypothesized that earlier repair in the neonatal period is associated with increased mortality and morbidity.

METHODS

This was a retrospective analysis of the Pediatric Health Information System of tetralogy of Fallot patients undergoing complete repair from 2004 through 2010 between the ages of 1 day to younger than 19 years. Patients with pulmonary valve atresia, those who received prostaglandin during hospital admission, and those who underwent prior shunt palliation were excluded.

RESULTS

A total of 4698 patients met our inclusion criteria, of whom 202 were younger than 30 days old (group A), 861 were 31 to 90 days old (group B), 1796 were 91 to 180 days old (group C), and 1839 were older than 180 days (group D). In-hospital mortality, intensive care unit length of stay, and total hospital length of stay were significantly higher in group A. Patients in group A had a significantly increased postoperative requirement for mechanical ventilation, intravenous blood pressure support, medical diuresis, extracorporeal membrane oxygenation, gastrostomy tube insertion, heart catheterization, and surgical revision. Significant institutional variability was noted for timing of TOF complete repair, with one third of the centers performing 75% of the repairs at younger than 30 days old. The institutional approach to timing TOF complete repair showed no relation to surgical volume.

CONCLUSIONS

Across all centers analyzed, primary neonatal elective TOF repair (<30 days of age) is associated with significantly higher postoperative in-hospital morbidity and mortality, although a few centers have shown an ability to use this strategy with excellent survivability.

Safety and efficacy of dexmedetomidine in children with heart failure

This retrospective observational study aimed to evaluate the safety and efficacy of dexmedetomidine (DEX) for children with heart failure. The study was conducted in the cardiovascular intensive care unit (CVICU) of a single, tertiary care, academic children's hospital. A retrospective review of the charts for all children (up to 18 years of age) with signs and symptoms consistent with congestive heart failure who received DEX in our CVICU between April 2006 and April 2011 was performed. The patients were divided into two groups for study purposes: the DEX group of 21 patients, who received a DEX infusion together with other conventional sedation agents, and the control group of 23 patients, who received conventional sedation agents without the use of DEX. To evaluate the safety of DEX, physiologic data were collected including heart rate, mean arterial pressure (MAP), and inotrope score. To assess the efficacy of DEX, the amount and duration of concomitant sedation and analgesic infusions in both the DEX and control groups were examined. The numbers of rescue boluses for each category before the initiation of sedative infusion and during the sedative infusion also were examined. The baseline characteristics of the patients in the two groups were similar. There was no effect of DEX infusion on heart rate, MAP, or inotrope score at the termination of infusion. The daily amount of midazolam administered was significantly less during the last 24 h of DEX infusion in the DEX group than in the control group (p = 0.04). The daily amount of morphine infusion did not differ between the DEX and control groups during any period. The numbers of sedation and analgesic rescue boluses were lower in DEX group throughout the infusion. No other significant side effects were noted. Two patients in the DEX group had a 50 % or greater drop in MAP compared with baseline in the first 3 h after initiation of DEX infusion, whereas one patient had a 50 % or greater drop in heart rate compared with baseline in the first 3 h after initiation of DEX infusion. Administration of DEX for children with heart failure appears to be safe but should be used cautiously. Furthermore, DEX use is associated with a decreased opiate and benzodiazepine requirement for children with heart failure.

Efficacy and predictors of success of noninvasive ventilation for prevention of extubation failure in critically ill children with heart disease

The study aimed primarily to evaluate the efficacy of noninvasive ventilation (NIV) and to identify possible predictors for success of NIV therapy in preventing extubation failure in critically ill children with heart disease. The secondary objectives of this study were to assess the efficacy of prophylactic NIV therapy initiated immediately after tracheal extubation and to determine the characteristics, outcomes, and complications associated with NIV therapy in pediatric cardiac patients. A retrospective review examined the medical records of all children between the ages 1 day and 18 years who sustained acute respiratory failure (ARF) that required NIV in the cardiovascular intensive care unit (CVICU) at Lucile Packard Children's Hospital between January 2008 and June 2010. Patients were assigned to a prophylactic group if NIV was started directly after extubation and to a nonprophylactic group if NIV was started after signs and symptoms of ARF developed. Patients were designated as responders if they received NIV and did not require reintubation during their CVICU stay and nonresponders if they failed NIV and reintubation was performed. The data collected included demographic data, preexisting conditions, pre-event characteristics, event characteristics, and outcome data. The outcome data evaluated included success or failure of NIV, duration of NIV, CVICU length of stay (LOS), hospital LOS, and hospital mortality. The two complications of NIV assessed in the study included nasal bridge or forehead skin necrosis and pneumothorax. The 221 eligible events during the study period involved 172 responders (77.8 %) and 49 nonresponders (22.2 %). A total of 201 events experienced by the study cohort received continuous positive airway pressure (CPAP), with 156 responders (78 %), whereas 20 events received bilevel positive airway pressure (BiPAP), with 16 responders (80 %). In the study, 58 events (26.3 %) were assigned to the prophylactic group and 163 events (73.7 %) to the nonprophylactic group. Compared with the nonprophylactic group, the prophylactic group experienced significantly shorter CVICU LOS (median, 49 vs 88 days; p = 0.03) and hospital LOS (median, 60 vs 103 days; p = 0.05). The CVICU LOS and hospital LOS did not differ significantly between the responders (p = 0.56) and nonresponders (p = 0.88). Significant variables identifying a responder included a lower risk-adjusted classification for congenital heart surgery (RACHS-1) score (1-3), a good left ventricular ejection fraction, a normal respiratory rate (RR), normal or appropriate oxygen saturation, prophylactic or therapeutic glucocorticoid therapy within 24 h of NIV initiation, presence of atelectasis, fewer than two organ system dysfunctions, fewer days of intubation before extubation, no clinical or microbiologic evidence of sepsis, and no history of reactive airway disease. As a well-tolerated therapy, NIV can be safely and successfully applied in critically ill children with cardiac disease to prevent extubation failure. The independent predictors of NIV success include lower RACHS-1 classification, presence of atelectasis, steroid therapy received within 24 h after NIV, and normal heart rate and oxygen saturations demonstrated within 24 h after initiation of NIV.

Impact of 22q11.2 deletion on the postoperative course of children after cardiac surgery

The primary objective of this study was to describe the impact of 22q11.2 deletion (del22q11) on the clinical characteristics, postoperative course, and short-term outcomes of children undergoing surgery for congenital heart disease. The charts of all children ages 1 day-18 years who received cardiac surgery for interrupted aortic arch (IAA), tetralogy of Fallot (TOF), or truncus arteriosus (TA) repair from 1 January 2001 to 31 December 2011 were retrospectively reviewed. The patients were divided into two groups: the 22q11 group including children with del22q11 undergoing surgery for TOF, IAA, or TA and the non-22q11 or control group including children with no chromosomal or genetic abnormality undergoing surgery for TOF, IAA, or TA. Demographic information, cardiac diagnoses, noncardiac abnormalities, preoperative factors, intraoperative details, surgical procedures performed, postoperative complications, and in-hospital deaths were collected. The outcome data collected included days of inotrope use, need for dialysis, length of mechanical ventilation, intensive care unit (ICU) length of stay (LOS), hospital LOS, and mortality. The study enrolled 173 patients: 65 patients in the 22q11 group and 108 patients in the control group. Of the 65 patients in the 22q11 group, 36 (55 %) underwent repair for TOF, 13 (20 %) for IAA, and 16 (25 %) for TA. The two groups did not differ in terms of age or weight. The preexisting conditions were similar in the two groups. Unplanned noncardiac operations were more common in the children with del22q11, but delayed chest closure was similar in the two groups. The incidence of postoperative noncardiac complications such as reintubation, vocal cord paralysis, and diaphragmatic paralysis was similar in the two groups. However, increasing numbers of patients in del22q11 group needed dialysis in one form or the other during the immediate postoperative stay. The incidence of fungal infection and wound infection was higher in the del22q11 group than in the control group. Duration of mechanical ventilation, ICU LOS, and hospital LOS were similar in the two groups, except in certain subgroups. Mortality did not differ significantly between the two groups. In conclusion, children with del22q11 have a higher risk of postoperative complications after cardiac surgery, with no difference in length of mechanical ventilation, ICU LOS, hospital LOS, or mortality. However, short-term outcomes may differ in certain subgroups.

Conal septal morphometrics can identify higher risk neonates with tetralogy of Fallot

BACKGROUND

Some neonates with tetralogy of Fallot (TOF) have rapid progression of right ventricular outflow tract obstruction, requiring early repair irrespective of Doppler gradient as measured in the neonatal period. The aim of this study was to test the hypothesis that infundibular morphology in neonates with TOF is associated with the occurrence of hypercyanotic spells and need for neonatal surgery.

METHODS

Fifty patients with TOF undergoing surgical repair from 2003 to 2009 were studied. Neonatal echocardiograms were retrospectively analyzed to measure conal septal angle (the angle between the conal septum and the horizontal plane passing through the center of the aortic valve in the parasternal short-axis view, with a larger angle denoting more anterocephalad deviation of conal septum), conal septal thickness and length, the degree of aortic dextroposition, and sizes and Z scores of the pulmonary annulus and the main and branch pulmonary arteries. Outcomes included the occurrence of hypercyanotic spells and the need for neonatal surgery.

RESULTS

The median age at first echocardiogram was 2 days (range, 0-12 days). The median age at surgery was 94 days (range, 5-282 days); hypercyanotic spells occurred in 17 patients (34%), and nine (18%) underwent neonatal repair. The presence of a wider conal septal angle was significantly associated with the occurrence of hypercyanotic spells (59 ± 21° vs 48 ± 13°, P = .023) and the need for neonatal surgery (67 ± 13° vs 48 ± 16°, P = .004). The positive and negative predictive values of hypercyanotic spells for conal septal angles ≥60° were 64% and 78%, respectively. Importantly, Doppler right ventricular outflow tract gradient at initial echocardiography, degree of aortic dextroposition, and pulmonary or aortic valve size were not associated with these outcomes.

CONCLUSIONS

A wider conal septal angle is associated with the occurrence of hypercyanotic spells and the need for neonatal surgery.

Early detection of cardiac dysfunction by strain and strain rate imaging in children and young adults with marfan syndrome

OBJECTIVES

Strain and strain rate imaging have been reported to detect cardiac dysfunction more accurately than conventional methods in adults with Marfan syndrome, but their utility has not been proven in younger patients. We sought to determine whether strain and strain rate imaging would allow early detection of cardiac dysfunction in children and young adults with Marfan syndrome.

METHODS

Unoperated patients (<30 years) with Marfan syndrome and healthy control participants were prospectively enrolled. Patients with greater than mild mitral or aortic insufficiency were excluded. Left ventricular systolic function was assessed by standard M-mode imaging. The strain and strain rate values were obtained from apical 4-chamber (longitudinal) and parasternal short-axis views at basal and midventricular levels (radial and circumferential). Data from the two groups were compared by a t test.

RESULTS

Sixteen patients with Marfan syndrome (mean age ± SD, 14.4 ± 6.4 years; range, 5.8-28.9 years) and 26 controls (mean age, 12.4 + 4.4 year; range, 4.1-18.1 years) were enrolled. Demographics and left ventricular end-diastolic dimensions were similar between the patients with Marfan syndrome and the controls. The M-mode-derived shortening fraction was significantly lower in the patients with Marfan syndrome compared to the controls, even though the values were within normal limits. The patients with Marfan syndrome had lower regional radial and circumferential strain rates, but there were no significant difference in strain between the groups.

CONCLUSIONS

Strain rate imaging may be useful in detection of subclinical changes in cardiac function in patients with Marfan syndrome when conventional echocardiographic parameters are within normal limits. These findings may be clinically important and warrant closer follow-up of these patients to monitor for cardiac dysfunction.

Hemodynamic effects of dexmedetomidine in critically ill neonates and infants with heart disease

The primary objective of this study was to evaluate the hemodynamic effects of dexmedetomidine (DEX) infusion on critically ill neonates and infants with congenital heart disease (CHD). The secondary objective of the study was to evaluate the safety and efficacy profile of the drug in this patient population. A retrospective observational study was conducted in the cardiovascular intensive care unit (CVICU) of a single tertiary care university children's hospital. The charts of all neonates and infants who received DEX in the authors' pediatric CVICU between August 2009 and June 2010 were retrospectively reviewed. The demographic data collected included age, weight, sex, diagnosis, and Risk Adjustment in Congenital Heart Surgery (RACHS-1) score. To evaluate the hemodynamic effects of DEX, physiologic data were collected including heart rate, mean arterial pressure (MAP), inotrope score, near-infrared spectroscopy, and central venous pressure (CVP). To assess the efficacy of DEX, the amount and duration of concomitant sedation and analgesic infusions over a period of 24 h were examined together with the number of rescue boluses. The potential side effects evaluated in this study included nausea, vomiting, abdominal distension, dysrhythmias, neurologic abnormalities, seizures, and signs and symptoms of withdrawal. During the study period, 50 neonates and infants received DEX for a median period of 78 h (range, 40-290 h). These patients had an average age of 3.53 ± 2.64 months and a weight of 4.85 ± 1.67 kg. Whereas 34 patients (68%) received DEX after surgery for CHD, 15 patients (30%) received DEX after heart transplantation. Of these 50 infants, 10 (20%) had a single-ventricle anatomy, whereas 13 (26%) had a risk adjustment score (RACHS-1) in the category of 4-6. The median CVICU stay was 29 days (range, 8-69 days). Despite a significant decrease in heart rate, MAP, inotrope score, and CVP, all the patients remained hemodynamically stable during DEX infusion. There was no substantial difference in major hemodynamic variables between neonates and infants, single- and two-ventricle repair, RACHS 4-6 and RACHS 1-3 categories for patients undergoing surgery, or patients undergoing heart transplantation and patients undergoing other surgical procedures. Dexmedetomidine infusion for neonates and infants with heart disease is safe from a hemodynamic standpoint and can reduce the concomitant dosing of opioid and benzodiazepine agents. Furthermore, DEX infusion may be useful for reducing vasopressor agent dosing in children with catecholamine-refractory cardiogenic shock.

Predictors for use of temporary epicardial pacing wires after pediatric cardiac surgery

OBJECTIVE

The objectives of this study were (1) to determine the use of temporary epicardial pacing wires to diagnose and treat early postoperative arrhythmias in pediatric cardiac surgical patients and (2) to determine the predictive factors for the need of pacing wires for diagnostic or therapeutic purposes.

METHODS

We collected preoperative, intraoperative, and postoperative data in a prospective, observational format from patients undergoing pediatric cardiac surgery between August 2010 and January 2011 at a single academic children's hospital.

RESULTS

A total of 157 patients met the inclusion criteria during the study period. Of these 157 patients, pacing wires were placed in 127 (81%). Pacing wires were used in 25 patients (19.6%) for diagnostic purposes, 26 patients (20.4%) for therapeutic purposes, 15 patients (11.8%) for both diagnostic and therapeutic purposes, and 36 patients (28.3%) for diagnostic or therapeutic purposes. Need for cardioversion in the operating room, presence of 2 or more intracardiac catheters, severely reduced ventricular ejection fraction, and elevated serum lactate level at the time of operating room discharge were found to be independent predictors for the use of pacing wires. The only complication noted in the cohort was a skin infection at a pacing wire insertion site in 1 patient. A permanent pacemaker was required in 8 (6.2%) of all patients with temporary pacing wires.

CONCLUSIONS

Our data support the use of temporary epicardial pacing wires in approximately 30% of children after congenital heart surgery. We found the need for cardioversion in the operating room, presence of 2 or more intracardiac catheters, severely reduced ventricular ejection fraction, and high serum lactate level at the time of discharge from the operating room to be independent predictors of the use of pacing wires in the early postoperative period.