Utpal Bhalala

Change in regional (somatic) near-infrared spectroscopy is not a useful indictor of clinically detectable low cardiac output in children after surgery for congenital heart defects

Objective: Near-infrared spectroscopy correlation with low cardiac output has not been validated. Our objective was to determine role of splanchnic and/or renal oxygenation monitoring using near-infrared spectroscopy for detection of low cardiac output in children after surgery for congenital heart defects. Design: Prospective observational study. Setting: Pediatric intensive care unit of a tertiary care teaching hospital. Patients: Children admitted to the pediatric intensive care unit after surgery for congenital heart defects. Interventions: None. Measurements and Main Results: We hypothesized that splanchnic and/or renal hypoxemia detected by near-infrared spectroscopy is a marker of low cardiac output after pediatric cardiac surgery. Patients admitted after cardiac surgery to the pediatric intensive care unit over a 10-month period underwent serial splanchnic and renal near-infrared spectroscopy measurements until extubation. Baseline near-infrared spectroscopy values were recorded in the first postoperative hour. A near-infrared spectroscopy event was a priori defined as ≥20% drop in splanchnic and/or renal oxygen saturation from baseline during any hour of the study. Low cardiac output was defined as metabolic acidosis (pH <7.25, lactate >2 mmol/L, or base excess ⩽−5), oliguria (urine output <1 mL/kg/hr), or escalation of inotropic support. Receiver operating characteristic analysis was performed using near-infrared spectroscopy event as a diagnostic test for low cardiac output. Twenty children were enrolled: median age was 5 months; median Risk Adjustment for Congenital Heart Surgery category was 3 (1–6); median bypass and cross-clamp times were 120 mins (45–300 mins) and 88 mins (17–157 mins), respectively. Thirty-one episodes of low cardiac output and 273 near-infrared spectroscopy events were observed in 17 patients. The sensitivity and specificity of a near-infrared spectroscopy event as an indicator of low cardiac output were 48% (30%–66%) and 67% (64%–70%), respectively. On receiver operating characteristic analysis, neither splanchnic nor renal near-infrared spectroscopy event had a significant area under the curve for prediction of low cardiac output (area under the curve: splanchnic 0.45 [95% confidence interval 0.30–0.60], renal 0.51 [95% confidence interval 0.37–0.65]). Conclusions: Splanchnic and/or renal hypoxemia as detected by near-infrared spectroscopy may not be an accurate indicator of low cardiac output after surgery for congenital heart defects.

Diagnostic Errors in a PICU: Insights from the Morbidity and Mortality Conference

Objectives: To describe diagnostic errors identified among patients discussed at a PICU morbidity and mortality conference in terms of Goldman classification, medical category, severity, preventability, contributing factors, and occurrence in the diagnostic process. Design: Retrospective record review of morbidity and mortality conference agendas, patient charts, and autopsy reports. Setting: Single tertiary referral PICU in Baltimore, MD. Patients: Ninety-six patients discussed at the PICU morbidity and mortality conference from November 2011 to December 2012. Interventions: None. Measurements and Main Results: Eighty-nine of 96 patients (93%) discussed at the PICU morbidity and mortality conference had at least one identified safety event. A total of 377 safety events were identified. Twenty patients (21%) had identified misdiagnoses, comprising 5.3% of all safety events. Out of 20 total diagnostic errors identified, 35% were discovered at autopsy while 55% were reported primarily through the morbidity and mortality conference. Almost all diagnostic errors (95%) could have had an impact on patient survival or safety. Forty percent of errors did not cause actual patient harm, but 25% were severe enough to have potentially contributed to death (40% no harm vs 35% some harm vs 25% possibly contributed to death). Half of the diagnostic errors (50%) were rated as preventable. There were slightly more system-related factors (40%) solely contributing to diagnostic errors compared with cognitive factors (20%); however, 35% had both system and cognitive factors playing a role. Most errors involved vascular (35%) followed by neurologic (30%) events. Conclusions: Diagnostic errors in the PICU are not uncommon and potentially cause patient harm. Most appear to be preventable by targeting both cognitive- and system-related contributing factors. Prospective studies are needed to further determine how and why diagnostic errors occur in the PICU and what interventions would likely be effective for prevention.

Computed tomography scan measurement of abdominal wall thickness for application of near-infrared spectroscopy probes to monitor regional oxygen saturation index of gastrointestinal and renal circulations in children.

Objectives: To measure abdominal wall thickness to determine the depth at which the renal vascular bed and mesenteric vascular bed are located, and to determine the appropriate site for placement of near-infrared spectroscopy probes for accurate monitoring regional oxygen saturation index in children. Design: Abdominal computerized tomography scans in children were used to measure the abdominal wall thickness and to ascertain the location of kidneys. Setting: Tertiary care childrens hospital. Subjects: Children 0–18 yrs of age; n = 38. Interventions: None. Measurements and Main Results: The main mass of the kidneys is located between vertebral levels T12 and L2 on both sides. The left kidney is located about a half-vertebral length higher than the right kidney. Posterior abdominal wall thickness ranged from 6.6 to 115.8 mm (median, 22.1 mm). Posterolateral abdominal wall thickness ranged from 6.7 to 114.5 mm (median, 19.6 mm). Anterior abdominal wall thickness in the supraumbilical level ranged from 3.5 to 62.9 mm (median, 16.0 mm). All abdominal wall thicknesses correlated better with weight of the subjects than their age. Conclusion: Abdominal wall thickness potentially exceeds the sampling depth of currently used near-infrared spectroscopy probes above a certain body size. Application of current near-infrared spectroscopy probes and design of future probes should consider patient size variations in the pediatric population.

End-Tidal CO2-Guided Chest Compression Delivery Improves Survival in a Neonatal Asphyxial Cardiac Arrest Model

Objectives: To determine whether end-tidal CO2–guided chest compression delivery improves survival over standard cardiopulmonary resuscitation after prolonged asphyxial arrest. Design: Preclinical randomized controlled study. Setting: University animal research laboratory. Subjects: 1–2-week-old swine. Interventions: After undergoing a 20-minute asphyxial arrest, animals received either standard or end-tidal CO2–guided cardiopulmonary resuscitation. In the standard group, chest compression delivery was optimized by video and verbal feedback to maintain the rate, depth, and release within published guidelines. In the end-tidal CO2–guided group, chest compression rate and depth were adjusted to obtain a maximal end-tidal CO2 level without other feedback. Cardiopulmonary resuscitation included 10 minutes of basic life support followed by advanced life support for 10 minutes or until return of spontaneous circulation. Measurements and Main Results: Mean end-tidal CO2 at 10 minutes of cardiopulmonary resuscitation was 34 ± 8 torr in the end-tidal CO2 group (n = 14) and 19 ± 9 torr in the standard group (n = 14; p = 0.0001). The return of spontaneous circulation rate was 7 of 14 (50%) in the end-tidal CO2 group and 2 of 14 (14%) in the standard group (p = 0.04). The chest compression rate averaged 143 ± 10/min in the end-tidal CO2 group and 102 ± 2/min in the standard group (p < 0.0001). Neither asphyxia-related hypercarbia nor epinephrine administration confounded the use of end-tidal CO2–guided chest compression delivery. The response of the relaxation arterial pressure and cerebral perfusion pressure to the initial epinephrine administration was greater in the end-tidal CO2 group than in the standard group (p = 0.01 and p = 0.03, respectively). The prevalence of resuscitation-related injuries was similar between groups. Conclusions: End-tidal CO2–guided chest compression delivery is an effective resuscitation method that improves early survival after prolonged asphyxial arrest in this neonatal piglet model. Optimizing end-tidal CO2 levels during cardiopulmonary resuscitation required that chest compression delivery rate exceed current guidelines. The use of physiologic feedback during cardiopulmonary resuscitation has the potential to provide optimized and individualized resuscitative efforts.

Hands-On Defibrillation Skills of Pediatric Acute Care Providers During a Simulated Ventricular Fibrillation Cardiac Arrest Scenario

Introduction: Timely defibrillation in ventricular fibrillation cardiac arrest (VFCA) is associated with good outcome. While defibrillation skills of pediatric providers have been reported to be poor, the factors related to poor hands-on defibrillation skills of pediatric providers are largely unknown. The aim of our study was to evaluate delay in individual steps of the defibrillation and human and non-human factors associated with poor hands-on defibrillation skills among pediatric acute care providers during a simulated VFCA scenario. Methods: We conducted a prospective observational study of video evaluation of hands-on defibrillation skills of pediatric providers in a simulated VFCA in our childrens hospital. Each provider was asked to use pads followed by paddles to provide 2 J/kg shock to an infant mannequin in VFCA. The hands-on skills were evaluated for struggle with any step of defibrillation, defined a priori as >10 s delay with particular step. The data was analyzed using chi-square test with significant p-value < 0.05. Results: A total of 68 acute care providers were evaluated. Median time to first shock was 97 s (IQR: 60–122.5 s) and did not correlate with provider factors, except previous experience with the defibrillator used in study. The number of providers who struggled (>10 s delay) with each of connecting the pads/paddles to the device, using pads/paddles on the mannequin and using buttons on the machine was 34 (50%), 26 (38%), and 31 (46%), respectively. Conclusions: The defibrillation skills of providers in a tertiary care childrens hospital are poor. Both human and machine-related factors are associated with delay in defibrillation. Prior use of the study defibrillator is associated with a significantly shorter time-to-first shock as compared to prior use of any other defibrillator or no prior use of any defibrillator.

351: STUDY OF CPR AND TRANSPORT QUALITY METRICS USING GROUND AIR MEDICAL QUALITY TRANSPORT (GAMUT) DATA

www.ccmjournal.org Critical Care Medicine • Volume 46 • Number 1 (Supplement) Learning Objectives: With increased regionalization of pediatric and neonatal specialty care in the United States, over 200,000 patients are transported annually. No data exists on rates of cardiopulmonary resuscitation (CPR) during medical transport. Herein, we present the first multicenter, international report of CPR during medical transport using the large Ground and Air Medical qUality in Transport (GAMUT) database. Methods: GAMUT defines transport CPR as the number of transports during which CPR is performed from the time the transport team assumes care until hand-off is completed at the destination facility, accounts for multiple episodes of CPR in a single transport as only one episode and excludes CPR in progress when the team arrives. Monthly institutional GAMUT data were aggregated from January 2014 to March 2017 by institution. To eliminate spurious associations, institutions with < 20 transports were excluded. The rate of CPR per total transports was expressed as a percentage and then Spearman’s rho non-parametric associations were determined between CPR and advanced airway (per total transports), waveform capnography usage (per total advanced airways), average mobilization time in minutes from the start of referral until en route, 1st attempt intubation success rate (per total intubation attempts), DASH1A intubation success (Definitive Airway Sans Hypoxia/Hypotension on 1st attempt per total intubation attempts). For significant associations scatterplots and non-linear best-fit modeling were performed to functionally define the associations by maximizing the R2 value. Results: There were 72 institutions that had at least one CPR event during the study period. Two transport quality metrics were significantly associated with CPR: presence of an advanced airway and mobilization time (p < 0.001) (correlation coefficients +0.41 and -0.60, respectively). Other transport quality metrics such as waveform capnography, first attempt intubation, and DASH1A success rate were not significantly associated with CPR. Conclusions: Presence of advanced airway and mobilization time had a significant correlation with rate of CPR during transport. It is possible that the patients who needed CPR en route were extremely sick before transport and therefore they had an advanced airway and a short average mobilization time. Further studies are needed to understand the true relationship between the rate of CPR and transport quality metrics, and ultimately the impact and outcomes of patients receiving CPR during transport.

251: TEMPERATURE AND PERFUSION STRATEGY DURING CARDIOPULMONARY BYPASS (CPB) IN NEONATES AND INFANTS

www.ccmjournal.org Critical Care Medicine • Volume 46 • Number 1 (Supplement) Learning Objectives: Temperature and perfusion during cardiopulmonary bypass (CPB) are two modifiable variables which could potentially impact neurologic outcome in neonates and infants after surgery for congenital heart defect (CHD). We conducted an international survey to determine variability in practice of temperature and perfusion strategies during CPB at various children’s hospitals. Methods: We performed an anonymous, cross-sectional, cohort, internet-based survey involving pediatric cardiac surgical teams of America, Europe, Asia and Australia. The list of survey participants was developed using congenital heart surgery network. The content and phraseology of survey questions were developed in an iterative manner using modified Delphi method. Pediatric and cardiac intensivists, pediatric cardiac surgeons and perfusionists assessed the content and construct validity of the survey items. Pilot testing of the survey was performed for readability, clarity and functionality prior to finalization and distribution. The final survey was developed based on the response from these reviews. Results: Out of 1960 pediatric cardiac surgical team members to whom the survey was emailed, 284 (14.4%) responded. Of the 284 respondents, 280 (98.5%) were pediatric surgeons and 4 (1.4%) were perfusionists. Of the 153 respondents who answered all the questions, the proportion of practitioners from free-standing children’s versus university versus community hospital were 31%, 54% and 14%, respectively; from America, Europe, Asia and Australia were 32%, 46%, 19% and 3%, respectively. CPB flow in cc/ kg versus cc/sq meter cardiac index was used by 47% versus 53%. The goal mean arterial pressure on CPB used was 30–50 mm Hg by majority (78%). When using selective antegrade cerebral perfusion (SACP), 44% used cc/kg flow strategy whereas 20% used % base flow, 16% titrated to NIRS, 10% titrated to MAP and remaining had inconsistent approach. Mild, moderate, deep and profound hypothermia was used by 6%, 26%, 59% and 9% for Norwood stage 1, respectively. For ASD repair, 94% used mild; whereas for TAPVR and aortic arch repairs, 75% and 88% used moderate-to-deep hypothermia. Rectal probe was used by majority as temperature monitoring site. Arterial to nasopharyngeal cooling and rewarming gradients of 410°C were used by 71% of respondents. Conclusions: There is variability in practice of temperature and perfusion strategies during CPB in children. More work is needed to study the outcome differences following these strategies.

349: STUDY OF TEAMWORK DURING EMERGENT STERNOTOMY FOR POSTOPERATIVE TAMPONADE-ASSOCIATED ARREST

Critical Care Medicine • Volume 46 • Number 1 (Supplement) www.ccmjournal.org Learning Objectives: Teamwork is a critical component of resuscitation. There is a lack of sufficient information on teamwork during emergent sternotomy performed to relieve cardiac tamponade during arrest. We hypothesized that the complex task of emergent sternotomy performed to relieve postoperative cardiac tamponade during arrest is associated with inadequate teamwork. Methods: We conducted a prospective observational study using a mannequin with a median sternotomy and the capability of reproducing cardiac tamponade. Our cardiac intensive care unit (CICU) team members who participated in the postoperative cardiac tamponade scenarios were expected to perform cardiopulmonary resuscitation (CPR). The CICU attending was expected to perform emergent sternotomy to relieve the cardiac tamponade during CPR. The video recordings of all the scenarios were analyzed for team performance. The data was analyzed using univariate analysis. Results: A total 54 CICU providers (37 nurses, 8 faculty, 7 advanced providers and 2 respiratory therapists) participated in 8 cardiac tamponade scenarios. The median (IQR) time for the bedside nurse to recognize deterioration and call for help was 16 (14–19) seconds. A code team leader was perceived to be identified clearly in 4/8 (50%), not clearly in 2/8 (25%) and not identified in 2/8 (25%) of the scenarios. Among the scenarios with clear leadership, an unannounced transition of leadership occurred in one, whereas in the remaining 3/4 (75%) scenarios, the physician continued leadership during the sternotomy. All except one scenario had all the roles perceived to be assigned for airway support, vascular access, chest compression and sternotomy assistance. A documentor was defined in all (100%) cases, but the documentor was perceived to be keeping a track of time and alerting team of upcoming tasks in only 5/8 (63%) cases. Closed loop communication was observed in 6/8 (75%) of scenarios and communication with the cardiothoracic surgeon was attempted in all the scenarios. Conclusions: The complex task of emergent sternotomy performed to relieve postoperative cardiac tamponade during arrest is associated with inadequate teamwork, especially team leadership.