Christopher Jenks

Regional cerebral abnormalities measured by frequency-domain near-infrared spectroscopy in pediatric patients during extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a form of advanced cardiorespiratory support provided to critically ill patients with severe respiratory or cardiovascular failure. While children undergoing ECMO therapy have significant risk for neurological morbidity, currently there is a lack of reliable bedside tool to detect the neurologic events for patients on ECMO. This study assessed the feasibility of frequency-domain near-infrared spectroscopy (NIRS) for detection of intracranial complications during ECMO therapy. The frequency-domain NIRS device measured the absorption coefficient (µa) and reduced scattering coefficient (µs′) at six cranial positions from seven pediatric patients (0–16 years) during ECMO support and five healthy controls (2–14 years). Regional abnormalities in both absorption and scattering were identified among ECMO patients. A main finding in this study is that the abnormalities in scattering appear to be associated with lower-than-normal µs′ values in regional areas of the brain. Because light scattering originates from the intracellular structures (such as nuclei and mitochondria), a reduction in scattering primarily reflects loss or decreased density of the brain matter. The results from this study indicate a potential to use the frequency-domain NIRS as a safe and complementary technology for detection of intracranial complications during ECMO therapy.

An International Survey on Ventilator Practices Among Extracorporeal Membrane Oxygenation Centers.

Although the optimal ventilation strategy is unknown for patients placed on extracorporeal support, there are increasing reports of extubation being used. Our objective was to describe the change in ventilation strategies and use of tracheostomy and bronchoscopy practices among extracorporeal membrane oxygenation (ECMO) centers across the world. A descriptive, cross-sectional 22 item survey of neonatal, pediatric, and adult ECMO centers was used to evaluate ventilator strategies, extubation, bronchoscopy, and tracheostomy practices. Extubation practices are increasing among all types of ECMO centers, representing 27% of all patients in pediatric centers, 41% of all patients in mixed centers, and 52% of all patients in adult centers. The most common mode of ventilation during ECMO is pressure control. There is a trend toward increased use of bilevel ventilation particularly for lung recruitment. Additionally, there is a trend toward increase in performance of bronchoscopy (pediatrics: 69%, mixed centers: 81%, adults: 76%) and tracheostomy. Among the centers performing tracheostomies, 45% reported the percutaneous method (pediatric: 31%, mixed: 46%, adult: 57%), 19% reported the open method (pediatric: 9%, mixed: 27%, adult: 24%), and 10% reported using both types of tracheostomies (pediatric: 2%, mixed: 8%, adult: 16%). Our study shows that ECMO centers are extubating their patients, performing tracheostomies and bronchoscopies on their patients more than in the previous years. There remains significant variation in ECMO ventilator strategies and management internationally. Future studies are needed to correlate these changes in practices to outcome benefits.

Drug hypersensitivity causing organizing eosinophilic pneumonia in a pediatric patient

Abstract Objective To describe a relatively rare hypersentivity reaction with pulmonary manifestations in a pediatric patient. Data sources Electronic medical records. Study selection Patient treatment in the pediatric critical care unit. Data extraction and synthesis Electronic medical records. Conclusions Eosinophilic pneumonias are rare in the pediatric population. Peripheral eosinophilia is not necessary to make the diagnosis. Bronchoalveolar lavage is the diagnostic study of choice. Lung biopsies are rarely needed to make the diagnosis. The treatment of choice is steroids. If steroids fail to improve the patients condition, consider IVIG, and cyclosporine A.

Pulmonary Graft Dysfunction and Elevated Pulmonary Pressures

We would like to congratulate Fruchter et al 1 for their ingenious, effective, and minimally invasive way of treating the very challenging condition of bronchopleural fi stulas as reported in a recent issue of CHEST (March 2011). However, because we were cited in their work, we must make a correction. The misunderstanding is that our fi rst publication was a case report of our fi rst patient (53-year-old man with a right upper lobectomy) using this method. 2 Later, Scordamaglio et al 3 published a review of our experience endoscopically treating airway fi stulas (two bronchopleural and one tracheoesophageal), which included this same patient. Since then, fi ve more fi stulas in four other patients have been treated, making a total of seven fi stulas treated in six patients (one patient with two fi stulas), with fi ve of them already closed. Although the technique used is similar to that in Fruchter et al, 1

High Hemoglobin Is an Independent Risk Factor for the Development of Hemolysis During Pediatric Extracorporeal Life Support

Objective: To evaluate risk factors for hemolysis in pediatric extracorporeal life support. Design: Retrospective, single-center study. Setting: Pediatric intensive care unit. Patients: Two hundred thirty-six children who received extracorporeal membrane oxygenation. Interventions: None. Measurements and Main Results: Risk factors for hemolysis were retrospectively analyzed from a single center in a total of 236 neonatal and pediatric patients who received extracorporeal membrane oxygenation support (ECMO). There was no difference in the incidence of hemolysis between centrifugal (127 patients) and roller head (109 patients) pump type or between venoarterial and venovenous ECMO. High hemoglobin (Hb) was found to be an independent risk factor for hemolysis in both pump types. The Hb level >12 g/dL was significant in the roller group and the Hb level >13 g/dL was significant in the centrifugal group for the development of hemolysis for the cumulative ECMO run. The presence of high Hb levels on any given day increased the risk of hemolysis for that day of the ECMO run regardless of ECMO pump type. Higher revolutions per minute (RPMs) and higher inlet pressures on any given day increased the risk for the development of hemolysis in the centrifugal pump. Lower inlet venous pressures and RPMs were not associated with hemolysis in the roller group. Conclusions: An Hb level greater than 13 g/dL was associated with an increased risk of hemolysis, and a high Hb on a given day was associated with a significantly higher risk of hemolysis on the same day. Higher RPMs and lower inlet venous pressures were associated with an increased risk of hemolysis in the centrifugal pump only.

Elevated cranial ultrasound resistive indices are associated with improved neurodevelopmental outcomes one year after pediatric cardiac surgery: A single center pilot study

Objective To determine if a non‐invasive, repeatable test can be used to predict neurodevelopmental outcomes in patients with congenital heart disease. Methods This was a prospective study of pediatric patients less than two months of age undergoing congenital heart surgery at the Childrens Health Childrens Medical Center at Dallas. Multichannel near‐infrared spectroscopy (NIRS) was utilized during the surgery, and ultrasound (US) resistive indices (RI) of the major cranial vessels were obtained prior to surgery, immediately post‐operatively, and prior to discharge. Pearsons correlation, Fischer exact t test, and Fischer r to z transformation were used where appropriate. Results A total of 16 patients were enrolled. All had US data. Of the sixteen patients, two died prior to the neurodevelopmental testing, six did not return for the neurodevelopmental testing, and eight patients completed the neurodevelopmental testing. There were no significant correlations between the prior to surgery and prior to discharge US RI and neurodevelopmental outcomes. The immediate post‐operative US RI demonstrated a strong positive correlation with standardized neurodevelopmental outcome measures. We were able to demonstrate qualitative differences using multichannel NIRS during surgery, but experienced significant technical difficulties implementing consistent monitoring. Conclusions A higher resistive index in the major cerebral blood vessels following cardiac surgery in the neonatal period is associated with improved neurological outcomes one year after surgery. Obtaining an ultrasound with resistive indices of the major cerebral vessels prior to and after surgery may yield information that is predictive of neurodevelopmental outcomes.

The Narcotic Prescription Problem: Prisoners of Our Own Design

Christopher L Jenks1* and Archana Dhar2 1Division of Pediatric Critical Care, Baylor College of Medicine, Texas Children’s Hospital, USA 2Division of Pediatric Critical Care, University of Texas Southwestern Medical Center, Children’s Health Children’s Medical Center at Dallas, USA *Corresponding author: Christopher L Jenks, Division of Pediatric Critical Care, Baylor College of Medicine, Texas Children’s Hospital, USA, Tel: + 8328266230; Email: Christopher.Jenks@UTSouthwestern.edu

179: EFFECTS OF NEGATIVE PRESSURE VENTILATION ON HEMODYNAMICS IN PATIENTS WITH CAVOPULMONARY SHUNTS

Learning Objectives: Children with cavopulmonary shunt (CPS) palliation for congenital heart disease often require mechanical ventilation. Positive pressure ventilation (PPV) worsens hemodynamics in these patients. Prior studies showed that negative pressure ventilation (NPV) delivered by a noninvasive cuirass ventilator increases venous return, pulmonary blood flow (Qp) and cardiac output (Qs), though methodological limitations, including the use of high tidal volumes (Vt) in the PPV groups, may account for these effects. We hypothesize in comparison to current PPV strategies, NPV is a safe alternative that improves Qp and Qs in patients with CPS. Methods: We performed a prospective, crossover pilot study in children with CPS undergoing elective cardiac catheterization. We recorded hemodynamic variables, co-oxymetry and ventilator parameters during PPV and after 15 minutes of NPV. We targeted Vt of 6-8ml/kg during PPV and NPV. Results: Four patients met inclusion criteria. Three had superior CPS (Glenn), (mean age 2.6 years) and 1 had total CPS (Fontan) (age 10). All 4 had minimal change in vital signs during PPV and NPV. They had no difference in acid/base status, paCO2, or oxygenation. We observed no impact of NPV on Qs and Qs. For patients with superior CPS, mean Qp was 3.11 +/-0.42 (PPV) and 3.08 +/-0.67 (PPV), and mean Qs of 6.12 +/-1.95 (PPV) and 5.49 +/-1.38 (NPV); with a mean Qp:Qs of 0.54 to 1 +/-0.08 (PPV) and 0.57 to 1 +/-0.04 (NPV). Qs and Qp:Qs were unchanged in the Fontan patient. We noted reduced superior vena cava (SVC), pulmonary artery (PA) and left atrial (LA) pressures. SVC and PA pressures were 17.5 +/-1.8 (PPV) and 15 +/-1.6 (NPV); and LA pressure 13 +/-2.1 (PPV) and 10.3 +/-1.1 (NPV). The effect was most evident in patients with superior CPS. Conclusions: In comparison with PPV, NPV in patients with CPS maintains equivalent ventilation. NPV reduced SVC, PA and LA pressures but did not improve Qp and Qs. Further investigation is necessary to elucidate the impact of NPV in this population as well as in critically ill patients where the hemodynamic benefits of NPV may be more apparent.

Cysteine as a Biomarker for Obstructive Sleep Apnea

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