Angela T. Wratney

The endotracheal tube air leak test does not predict extubation outcome in critically ill pediatric patients

Objective: Endotracheal tube air leak pressures are used to predict postextubation upper airway compromise such as stridor, upper airway obstruction, or risk of reintubation. To determine whether the absence of an endotracheal tube air leak (air leak test ≥30 cm H2O) measured during the course of mechanical ventilation predicts extubation failure in infants and children. Design: Prospective, blinded cohort. Setting: Multidisciplinary pediatric intensive care unit of a university hospital. Patients: Patients younger than or equal to 18 yrs and intubated ≥24 hrs. Interventions: The pressure required to produce an audible endotracheal tube air leak was measured within 12 hrs of intubation and extubation. Unless prescribed by the medical care team, patients did not receive neuromuscular blocking agents during air leak test measurements. Measurements and Main Results: The need for reintubation (i.e., extubation failure) was recorded during the 24-hr postextubation period. Seventy-four patients were enrolled resulting in 59 observed extubation trials. The extubation failure rate was 15.3% (9 of 59). Seven patients were treated for postextubation stridor. Extubation failure was associated with a longer median length of ventilation, 177 vs. 78 hrs, p = 0.03. Extubation success was associated with the use of postextubation noninvasive ventilation (p = 0.04). The air leak was absent for the duration of mechanical ventilation (i.e., ≥30 cm H2O at intubation and extubation) in ten patients. Absence of the air leak did not predict extubation failure (negative predictive value 27%, 95% confidence interval 6–60). The air leak test was ≥30 cm H2O before extubation in 47% (28 of 59) of patients yet 23 patients extubated successfully (negative predictive value 18%). Conclusions: An endotracheal tube air leak pressure ≥30 cm H2O measured in the nonparalyzed patient before extubation or for the duration of mechanical ventilation was common and did not predict an increased risk for extubation failure. Pediatric patients who are clinically identified as candidates for an extubation trial but do not have an endotracheal tube air leak may successfully tolerate removal of the endotracheal tube. (Pediatr Crit Care Med 2008; 9:490–496)

National Survey of Pediatric Emergency Medicine Fellows on Debriefing After Medical Resuscitations

Background Medical resuscitations of critically ill children in the emergency department are stressful events requiring a coordinated team effort. Current guidelines recommend debriefing after such events to improve future performance. Debriefing practices within pediatric emergency departments by pediatric emergency medicine (PEM) fellows in the United States has not been studied. Objective The aim of this study was to describe the current debriefing experience of PEM fellows in the United States. Methods A 10-item, anonymous questionnaire regarding debriefing characteristics was distributed to fellows in US Accreditation Council for Graduate Medical Education–accredited PEM programs via e-mail and paper format from December 2011 to March 2012. Results were summarized using descriptive statistics. Results Of 393 eligible PEM fellows, 201 (51.1%) completed the survey. The 201 respondents included 82 first-year fellows (40.8%), 71 second-year fellows (35.3%), and 48 third-year fellows (23.9%). Ninety-nine percent had participated in medical resuscitations during their fellowship training, yet 88.0% reported no formal teaching on how to debrief. There was wide variability in the format and timing of debriefings. The majority of debriefings were led by PEM attending physicians (65.5%) and PEM fellows (19.6%). Most (91.5%) of the fellows indicated they would like further education about debriefing. Conclusions The majority of PEM fellows do not receive formal training on how to debrief after a critical event and may have limited experience in leading debriefings. Debriefing training should be considered part of the educational curriculum during PEM fellowship.

Application of a modified microbiologic criterion for identifying pediatric ventilator-associated pneumonia

BACKGROUND Prevention of ventilator-associated pneumonia (VAP) is a major patient safety goal, but accurate identification of VAP in pediatric patients remains challenging. METHODS We performed a retrospective cohort study to demonstrate feasibility of endotracheal culture and Grams stain to support VAP diagnosis. Pediatric intensive care unit and cardiac intensive care unit patients with ≥ 1 endotracheal specimen having growth of ≥ 1 organism in conjunction with moderate/many polymorphonuclear leukocytes (ie, the modified microbiologic criterion) were included. Medical records were reviewed for presence/absence of clinical and radiographic Centers for Disease Control and Prevention (CDC) criteria for VAP. Antimicrobial use data were collected before and after culture results were known. RESULTS Of 102 patients meeting inclusion criteria, 28% (n = 28) also met both clinical and radiographic CDC criteria for VAP (ie, diagnosis of PNU2). An additional 63% (n = 64) met clinical (36%; n = 37) or radiographic (27%; n = 27) criteria, but not both. Ten patients (9%) had neither clinical nor radiographic criteria for VAP. The majority (63%; n = 64) were receiving antibiotics at time of endotracheal specimen collection. Culture identification resulted in altered antimicrobial therapy in 66% of patients (n = 67). CONCLUSIONS Our study demonstrates the feasibility of endotracheal Grams stain and culture for diagnosis of pediatric VAP that could potentially standardize accurate surveillance and management of pediatric VAP.

An Evaluation of a New Debriefing Framework: REFLECT

Supplemental digital content is available in the text. Background Postresuscitation debriefing (PRD) is recommended by the American Heart Association guidelines but is infrequently performed. Prior studies have identified barriers for pediatric emergency medicine (PEM) fellows including lack of a standardized curriculum. Objective Our objective was to create and assess the feasibility of a time-limited, structured PRD framework entitled REFLECT: Review the event, Encourage team participation, Focused feedback, Listen to each other, Emphasize key points, Communicate clearly, and Transform the future. Methods Each PEM fellow (n = 9) at a single center was a team leader of a pre-intervention and post-intervention videotaped, simulated resuscitation followed by a facilitated team PRD. Our intervention was a 2-hour interactive, educational workshop on debriefing and the use of the REFLECT debriefing aid. Videos of the pre-intervention and post-intervention debriefings were blindly analyzed by video reviewers to assess for the presence of debriefing characteristics contained in the REFLECT debriefing aid. PEM fellow and team member assessments of the debriefings were completed after each pre-intervention and post-intervention simulation, and written evaluations by PEM fellows and team members were analyzed. Results All 9 PEM fellows completed the study. There was an improvement in the pre-intervention and post-intervention assessment of the REFLECT debriefing characteristics as determined by fellow perception (63% to 83%, P < 0.01) and team member perception (63% to 82%, P < 0.001). All debriefings lasted less than 5 minutes. There was no statistical difference between pre-intervention and post-intervention debriefing time (P = 1.00). Conclusions REFLECT is a feasible debriefing aid designed to incorporate evidence-based characteristics into a PRD.

Central venous saturation as a predictor of extubation failure.

T olerance of a spontaneous breathing test (SBT) indicates weaning success, but variably predicts extubation success. After successful SBT, the need for reintubation within the subsequent 24 hrs to 72 hrs occurs in 5% to 30% of patients, depending on the population (1). The difficult-to-wean patient, by definition, has failed to tolerate the initial SBT with successful weaning requiring up to three SBTs or up to no more than 7 days from the initial SBT evaluation. After a successful SBT in this population, 15% to 33% will fail the extubation trial and require reintubation (2). Thus, identifying a noninvasive measure during the SBT, which could accurately predict extubation outcome for these difficult-to-wean patients, would inform the clinical decision to extubate. In this issue of Critical Care Medicine, Teixeira et al (3) evaluate the change in central venous saturation (ScvO2) during the SBT as a predictor of extubation failure in difficult-to-wean patients. The authors hypothesized that ScvO2 could be a “reliable and convenient tool to rapidly warn about the acute changes in oxygen supply and demand of the patient during weaning.” Across three medical-surgical intensive care units, 73 patients mechanically ventilated for 48 hrs who had previously failed a 2-hr SBT were enrolled in the study. All patients were weaned, using a standardized two-step process which included daily readiness to wean assessments, a 2-hr T-piece SBT with measure of frequency/tidal volume (f/VT) ratio during the first 30-min interval, and measures of various physiologic and ventilatory parameters at 1 min and the 30 mins of the SBT. All patients had a subclavian or internal jugular central venous catheter present for ScvO2 measurement. Patients with an f/VT 105 or intolerance of the SBT were returned to ventilatory support and reassessed the next day (4, 5). Patients who had an f/VT 105 and who successfully passed an SBT were extubated and monitored for 48 hrs. The protocol among all three institutions included immediate use of noninvasive ventilation on extubation for all patients with chronic obstructive pulmonary disease. Extubation failure (EF) was defined as the need for reintubation within 48 hrs of extubation. EF occurred in 31 patients (42.5%). Significant differences between the EF and extubation success (ES) group were detected at the 30 minute of the SBT including an increased heart rate, lower PaO2, SaO2, and ScvO2 in the EF group. Multivariate regression identified ScvO2 as the only independent variable able to discriminate extubation outcome. At 30 mins of the SBT, the ScvO2 in the EF group was 60 8 as compared with 70 7 in ES group (p .009). A reduction in ScvO2 by 4.5% during the SBT was an independent predictor of reintubation, with an odds ratio of 49.5 (95% confidence interval, 12.1–201.5), sensitivity of 88% and specificity of 95%. These results indicate that ScvO2 measured during a T-piece trial may be an important part of the assessment of extubation readiness in the difficult-to-wean patient. The utility of ScvO2 as a surrogate for Sv O2 in clinical-decision making has been evaluated with conflicting results, particularly in the critically ill patient (6–9). The ScvO2 has performed well as a surrogate target for hemodynamic resuscitation, yet it seems to have a variable correlation with the Sv O2, depending on the patient’s disease and severity of cardiopulmonary status at the time of measurement. In 60 patients with low cardiac index, the limits of agreement between the Sv O2 and ScvO2 were 19% to 18% with a correlation coefficient of 0.46 to 0.72 (7). The correlation between these two measures has been evaluated among various populations of intensive care patients, resulting in estimates between 0.78 and 0.95 (6–9). Chawla et al found that ScvO2 overestimated the true Sv O2 by 5% and that large estimation errors occurred in calculating oxygen consumption (V̇O2) from substitution of the ScvO2 values (8). Using Sv O2 to predict weaning success and failure has been well described. Jubran et al reported the continuous measure of Sv O2 during the SBT could accurately discriminate among a cohort of 8 patients who had failed the SBT and 11 patients who passed the SBT (9). SvO2 fell persistently during the SBT in the failure group leading to systemic arterial desaturation. The EF group did not alter their oxygen consumption nor cardiac index, rather the oxygen extraction ratio was increased. Jubran et al concluded that the progressive decrease in Sv O2 during a failed SBT was due to a combination of decreased oxygen transport and increased oxygen extraction by the tissues. In the current study by Dr. Teixeira et al, a decrease in ScvO2 measured during the SBT was able to predict accurately extubation outcome. Other independent predictors of extubation outcome in difficult-towean patients include n-terminal probrain natriuretic peptide, measures of work of breathing, such as maximal inspiratory pressure, peak cough expiratory force, and secretion burden (10–13). Importantly, the study cohort evaluated difficult-to-wean patients. All patients had previously passed both an f/VT and SBT trial, which should indicate a high likelihood of ES. However, it is known that a high likelihood of EF occurs in the difficult-to-wean population and, therefore, the use of the ScvO2 as a predictor of extubation outcome may not be easily generalizable to other patient populations who may have a much higher probability for ES. The reader is, therefore, cautioned against using a decreased ScvO2 during the SBT as evidence to withhold a trial of extubation in the general patient population either passing their first SBT or otherwise having met extubation readiness criteria. The importance of appropriate application and interpretation of weaning-predictor tests has been previously described (14). Although this study has defined how to identify risk for failed extubation, it is *See also p. 491.

Dexmedetomidine as a primary sedative agent after single-stage airway reconstruction.

Objective To examine the outcomes of children receiving dexmedetomidine after single-stage airway reconstruction. Study Design Historical cohort study. Setting Tertiary care children’s hospital. Subjects and Methods Of 61 eligible patients, 50 children undergoing single-stage airway reconstruction were included in the study. Thirty children received dexmedetomidine (Dex) as a primary sedative agent, and 20 received a more traditional sedation protocol (no Dex). Primary outcomes included complications, intubation lengths, and lengths of pediatric intensive care unit (PICU)/hospital admission. Secondary analysis incorporating polypharmacy and age was performed using multivariate linear regression models. Results Median age was 18.0 months. Age, sex, and weight were similar between the groups. Intubation length was equal in the 2 groups, and there were no statistical differences between lengths of PICU or hospital stay after extubation. Similarly, overall and individual complications were all similar, and there was no difference between the 2 groups in the amount of polypharmacy administered. On multivariate analysis, polypharmacy and younger age were independently correlated with an increase in overall complications, and polypharmacy alone was correlated with an increased length of stay after extubation. Conclusion The use of dexmedetomidine as a primary sedation agent after single-stage airway surgery does not appear to improve outcomes or decrease the need for additional pharmacologic agents. Polypharmacy was associated with an increase in overall complications and an increased length of stay after extubation. Although success can be expected in greater than 90% of these surgical patients, the optimal postoperative sedation management remains challenging.