Adnan Bakar

238: THE RELATIONSHIP OF PDA FLOW PATTERNS WITH CLINICAL PARAMETERS IN NEONATES ON VENOVENOUS ECMO

Critical Care Medicine • Volume 46 • Number 1 (Supplement) www.ccmjournal.org Learning Objectives: Extracorporeal membrane oxygenation (ECMO) has been used in over 27,000 neonates with respiratory failure. Of these, approximately 6,700 have been treated with venovenous (VV) ECMO. Currently, more of these patients are being supported with VV ECMO, as ligation of the carotid artery is spared and central nervous system complications are lessened. Increases in pulmonary vascular resistance (PVR) may lead to extra-pulmonary shunting of blood via right-to-left (R-L) flow through the patent ductus arteriosus (PDA) and patent foramen ovale. Previous studies have shown that R-L flow before ECMO initiation is associated with lower survival rates. We hypothesized that the direction of flow within and size of the PDA while on VV ECMO would be associated with the need for conversion to VA ECMO and to survival. Methods: A retrospective chart review of patients supported with VV ECMO for neonatal respiratory failure from January 2011 through September 2015 in 3 academic children’s hospitals. PDA size, direction of blood flow, and estimation of pulmonary artery pressure (or PVR if the PDA was non-restrictive) were recorded by echocardiography closest to 48 hours on ECMO. Chisquared and Fisher Exact test were used where appropriate. Univariate and multivariate regression was performed to compare variables associated with survival and conversion from VV to VA ECMO. Results: 41 patients were initially supported on VV ECMO. Of these, 8 (19%) were converted to VA ECMO, and 30 (73%) survived. The average hour on ECMO for the echocardiogram was 71 hours (range 20–167 hours). On univariate analysis lower weight, a higher vasoactive infusion score (VIS), and use of iNO, milrinone, sildenafil and iloprost were associated with conversion to VA ECMO. The absence of renal or neurologic diagnosis, lower VIS, and no need for iNO, milrinone and sildenafil were associated with increased survival to 24 hours after decannulation. PDA size and direction of blood flow were not associated with conversion to VA ECMO or survival. No variables remained significant on multivariate analysis. Conclusions: PDA size and flow pattern in patients already on VV ECMO were not associated with conversion to VA ECMO or survival to 24 hours after decannulation. On univariate analysis other factors were associated with these endpoints.

Effect of Location on Tracheal Intubation Safety in Cardiac Disease—Are Cardiac ICUs Safer?

Objectives: Evaluate differences in tracheal intubation–associated events and process variances (i.e., multiple intubation attempts and oxygen desaturation) between pediatric cardiac ICUs and noncardiac PICUs in children with underlying cardiac disease. Design: Retrospective cohort study using a multicenter tracheal intubation quality improvement database (National Emergency Airway Registry for Children). Setting: Thirty-six PICUs (five cardiac ICUs, 31 noncardiac ICUs) from July 2012 to March 2016. Patients: Children with medical or surgical cardiac disease who underwent intubation in an ICU. Interventions: None. Measurements and Main Results: Our primary outcome was the rate of any adverse tracheal intubation–associated event. Secondary outcomes were severe tracheal intubation–associated events, multiple tracheal intubation attempt rates, and oxygen desaturation. There were 1,502 tracheal intubations in children with underlying cardiac disease (751 in cardiac ICUs, 751 in noncardiac ICUs) reported. Cardiac ICUs and noncardiac ICUs had similar proportions of patients with surgical cardiac disease. Patients undergoing intubation in cardiac ICUs were younger (median age, 1 mo [interquartile range, 0–6 mo]) compared with noncardiac ICUs (median 3 mo [interquartile range, 1–11 mo]; p < 0.001). Tracheal intubation–associated event rates were not different between cardiac ICUs and noncardiac ICUs (16% vs 19%; adjusted odds ratio, 0.74; 95% CI, 0.54–1.02; p = 0.069). However, in a sensitivity analysis comparing cardiac ICUs with mixed ICUs (i.e., ICUs caring for children with either general pediatric or cardiac diseases), cardiac ICUs had decreased odds of adverse events (adjusted odds ratio, 0.71; 95% CI, 0.52–0.97; p = 0.033). Rates of severe tracheal intubation–associated events and multiple attempts were similar. Desaturations occurred more often during intubation in cardiac ICUs (adjusted odds ratio, 1.61; 95% CI, 1.04–1.15; p = 0.002). Conclusions: In children with underlying cardiac disease, rates of adverse tracheal intubation–associated events were not lower in cardiac ICUs as compared to noncardiac ICUs, even after adjusting for differences in patient characteristics and care models.

231: INTRAOPERATIVE REGIONAL SATURATION TO PREDICT LOW CARDIAC OUTPUT SYNDROME AFTER CARDIAC SURGERY

Learning Objectives: Low cardiac output syndrome (LCOS) is a well-known sequelae of cardiopulmonary bypass (CPB) surgery. Near infrared spectroscopy (NIRS) is used to monitor regional saturation in CPB surgeries. Low NIRS and a derived desaturation score ≥3000% per second during CPB surgery have been shown to predict neurologic dysfunction and acute kidney injury. We aim to assess the predictive ability of intraoperative NIRS (desaturation score) and post-operative LCOS. Methods: Prospective observational study evaluating intra-operative cerebral and somatic NIRS in all children undergoing CPB and correlating with post-operative lactate and vasoactive inotropic score (VIS) as surrogates for LCOS in the first 24 hours. Secondary outcomes measured were ICU-free days, ventilator-free days (VFD), and number of fluid boluses required in first 24 hours. Results: 52 patients underwent CPB, of whom 28 had cerebral NIRS desaturation score ≥3000% per second and 8 had somatic NIRS desaturation score ≥3000% per second. A linear mixed-model regression showed that there is significant association between cerebral desaturation score <3000% per second and lactate (P<0.028) but no significant association between somatic NIRS and lactate. There is no significant association neither between cerebral nor somatic NIRS and VIS. There is no significant association between cerebral or somatic NIRS and VFD or ICU-free days. Conclusions: Lower derived cerebral desaturation score (<3000%/sec) is associated with increased post-operative lactate, a surrogate for LCOS. While this finding does not reflect previously published studies, this may be due to a small sample size; data collection is ongoing. Differences in cerebral and somatic NIRS might reflect the difference in auto regulation across these vascular beds. NIRS is a valuable tool in monitoring intraoperative regional desaturation and might have applicability in predicting post-operative low cardiac output syndrome. Studies with larger sample size are required to prove this conclusively.

Who is minding the store: intensive care unit personnel and its effect on cardiac arrest outcome.

Cardiac arrest is a frequent occurrence in pediatric cardiac intensive care units (ICUs) ranging between 4% and 6% of admitted patients with over half of these patients successfully resuscitated (1, 2). Several innovations have helped to improve the likelihood that patients will survive or avoid cardiac arrest in the first place, including the implementation of rapid response teams, the use of extracorporeal membrane oxygenation, and possibly therapeutic hypothermia (3). Most studies have concentrated on clinical factors that influence outcomes, but other factors, including specific coverage issues, could have an impact on clinical outcome after cardiopulmonary resuscitation (4, 5). For example, a study by Pronovost et al (4) found that ICUs with high-intensity staffing (i.e., closed ICU or mandatory ICU consult) had lower mortality rates than those with low-intensity staffing. In this issue of Pediatric Critical Care Medicine, Gaies et al (6) undertook a retrospective chart review to assess how personnel and other unit coverage factors affected outcomes after cardiac arrest in a pediatric cardiac ICU setting. They hypothesized that greater physician and nurse experience would be associated with a higher likelihood of successful resuscitation from cardiac arrest and that arrests occurring off-hours would be resuscitated less successfully. Their conclusions included a number of issues, both expected and surprising. Although nursing experience was associated with a better outcome, having a physician experienced in cardiac ICU was not. Specifically, patients cared for by junior nurses with <1 yr of cardiac intensive care experience did have worse outcomes than patients cared for by nurses with >1 yr of experience. In a multivariate analysis, nursing experience of <1 yr had a 9.4 better chance of unsuccessful resuscitation, whereas arrest on the weekend carried an unfavorable odds ratio of 4.4. However, weeknights did not carry a higher risk of poor outcome compared with day shifts. Other factors including bed census, patients’ bed space, number of unit admissions on that day, nursing ratio, and primary nurse or unit charge nurse did not have any impact on outcomes. The study is both timely and important given all of the press regarding healthcare economics and the need for high-quality care. Although most agree with the premise that experienced nurses make a difference at the bedside, dogma also exists about experienced physicians improving the quality of care of patients. However, in this study, having a dedicated cardiac intensivist had no impact on the success of resuscitation (4). Although this novel finding can affect unit staffing, there are several aspects of the study that merit closer inspection. Less experienced nurses were classified as having <1 yr of specific pediatric cardiac critical care experience. Whether the difference is attributable to cardiac critical care experience specifically or general nursing experience would help clarify the applicability of the study. Typically, it is understood that excellent nursing care can head off any potential morbidities and, in the case of cardiac arrest, avoid it altogether. Thus, the conclusion that the presence at the bedside of a more experienced cardiac ICU nurse results in a better outcome may relate to the performance of resuscitation. One would expect that with a more experienced nurse, fewer cardiac arrests would result in the ICU, an issue not studied here. The authors also noted no difference in resuscitation success between weekdays and weeknights. Other centers have reported a difference in resuscitation success “off-hours” and it would be interesting to analyze what these clinicians or ICUs do differently to eliminate this off-hour deficit (7). The study has a number of other limitations and idiosyncrasies related to a single-site study. For example, patients were placed on extracorporeal membrane oxygenation during cardiopulmonary resuscitation. This therapeutic maneuver would by definition increase the number of patients successfully resuscitated, because some of these patients would have surely died without extracorporeal membrane oxygenation availability. Given the limited use of extracorporeal membrane oxygenation during cardiopulmonary resuscitation internationally with its intense resource requirements, this study may be less applicable to institutions that do not use this modality. The authors also decided to use successful resuscitation as the marker of a good outcome rather than neurologic outcome or survival (8). The authors reasoned that a cardiac arrest in a patient who may have already undergone cardiopulmonary bypass and postoperative hemodynamic instability may not be the worst physiological insult to a patient while in the cardiac ICU. Thus, whether the differences seen in outcome as defined in the article would hold up if ultimate outcome was related to better functional outcome of the patient is unknown. Given the topical nature of both quality of care and healthcare costs, this study is interesting in that it can be looked at in two ways. The first is a literal interpretation in that outcome from cardiac arrest is affected positively by more experienced nurses at the bedside. The second interpretation is that outcome measure as defined in this study is used as a surrogate for clinical outcomes generally. The impact of nursing experience on this outcome measure probably cannot be understated. Whether physician experience related to cardiac ICU outcome can be extrapolated to any *See also p. 583.