Micheal L. Heard

Recovery of renal function and survival after continuous renal replacement therapy during extracorporeal membrane oxygenation.

Objective: To assess the outcome of pediatric patients supported by concomitant extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT). Design, Setting, and Patients: Acute kidney injury is associated with mortality in ECMO patients. CRRT in patients on ECMO provides an efficient and potentially beneficial method of acute kidney injury management. Concern that concomitant CRRT use increases the risk of developing anuria and chronic renal failure limits its use in some centers. We hypothesized that development of chronic renal failure is rare with concurrent ECMO and CRRT. We evaluated the outcomes of 154 ECMO/CRRT patients cared for over 10 yrs at a referral pediatric medical center. Interventions: None. Measurements and Main Results: Among 68 (44%) ECMO/CRRT survivors, 45 were assigned a pediatric risk, injury, failure, loss and end-stage (referred to as “pRIFLE”) score at CRRT initiation. Seventeen (38%) patients met the criteria for Risk, 15 (33%) for Injury, and 10 (22%) for Failure. Two Failure patients later met End stage criteria. Of all survivors, 18 (26%) required ongoing renal replacement therapy (15 required continuous veno-venous hemofiltration, two required peritoneal dialysis, and one patient required intermittent hemodialysis) post ECMO discontinuation. Renal recovery occurred in 65 (96%) of 68 patients before discharge. One neonatal patient had sepsis-induced renal injury on transfer, but had normal creatinine 1 month later. Two pediatric patients with vasculitis and primary renal disease at presentation (both meeting Failure criteria) developed end-stage renal disease. One received peritoneal dialysis and subsequent renal transplant. The other has diminished function without need for renal replacement therapy. Conclusion: In the absence of primary renal disease, chronic renal failure did not occur after concurrent use of CRRT with ECMO. Concern for precipitating chronic renal failure by using CRRT during ECMO is not substantiated by this large single-center experience. Consistent with previous reports, mortality is higher in patients receiving concomitant CRRT and ECMO compared with those receiving ECMO alone. Mortality is similar to patients requiring CRRT who are not on ECMO. Additional studies are warranted to determine the optimal role of CRRT use in ECMO patients.

Primary use of the venovenous approach for extracorporeal membrane oxygenation in pediatric acute respiratory failure.

Objectives To describe a single center’s experience with the primary use of venovenous cannulation for supporting pediatric acute respiratory failure patients with extracorporeal membrane oxygenation (ECMO). Design Retrospective chart review of all patients receiving extracorporeal life support at a single institution. Setting Pediatric intensive care unit at a tertiary care children’s hospital. Patients Eighty-two patients between the ages of 2 wks and 18 yrs with severe acute respiratory failure. Interventions ECMO for acute respiratory failure. Measurements and Main Results From January 1991 until April 2002, 82 pediatric patients with acute respiratory failure were cannulated for ECMO support. Median duration of ventilation before ECMO was 5 days (range, 1–17 days). Sixty-eight of these patients (82%) initially were placed on venovenous ECMO. Fourteen patients were initiated and remained on venoarterial support, including six in whom venovenous cannulae could not be placed. One patient was converted from venovenous to venoarterial support due to inadequate oxygenation. Venoarterial patients had significantly greater alveolar-arterial oxygen gradients and lower Pao2/Fio2 ratios than venovenous patients (p < .03). Fifty-five of 81 venovenous patients received additional drainage cannulae (46 of 55 with an internal jugular cephalad catheter). Thirty-five percent of venovenous patients and 36% of venoarterial patients required at least one vasopressor infusion at time of cannulation (p = nonsignificant); vasopressor dependence decreased over the course of ECMO in both groups. Median duration on venovenous ECMO for acute hypoxemic respiratory failure was 218 hrs (range, 24–921). Venovenous ECMO survivors remained cannulated for significantly shorter time than nonsurvivors did (median, 212 vs. 350 hrs; p = .04). Sixty-three of 82 ECMO (77%) patients survived to discharge—56 of 68 venovenous ECMO (81%) and nine of 14 venoarterial ECMO (64%). Conclusions Venovenous ECMO can effectively provide adequate oxygenation for pediatric patients with severe acute respiratory failure receiving ECMO support. Additional cannulae placed at the initiation of venovenous ECMO could be beneficial in achieving flow rates necessary for adequate oxygenation and lung rest.

Validation of the cas neonatal NIRS system by monitoring VV-ecmo patients : Preliminary results

The CAS neonatal NIRS system determines absolute regional brain tissue oxygen saturation (SnO2) and brain true venous oxygen saturation (SnvO2) non-invasively. Since NIRS-interrogated tissue contains both arterial and venous blood from arterioles, venules, and capillaries, SnO2 is a mixed oxygen saturation parameter, having values between arterial oxygen saturation (SaO2) and cerebral venous oxygen saturation (SvO2). To determine a reference for SnO2, the relative contribution of SvO2 to SaO2 drawn from a brain venous site vs. systemic SaO2 is approximately 70:30 (SvO2:SaO2). If the relationship of the relative average contribution of SvO2 and SaO2 is known and does not change to a large degree, then NIRS true venous oxygen saturation, SnvO2, can be determined non-invasively using SnO2 along with SaO2 from a pulse oximeter.

Experience with use of extracorporeal life support for severe refractory status asthmaticus in children

IntroductionSevere status asthmaticus (SA) in children may require intubation and mechanical ventilation with a subsequent increased risk of death. In the patient with SA and refractory hypercapnoeic respiratory failure, use of extracorporeal life support (ECLS) has been anecdotally reported for carbon dioxide removal and respiratory support. We aimed to review the experience of a single paediatric centre with the use of ECLS in children with severe refractory SA, and to compare this with international experience from the Extracorporeal Life Support Organization (ELSO) registry.MethodsAll paediatric patients (aged from 1 to 17 years) with primary International Classification of Diseases (ICD)-9 diagnoses of SA receiving ECLS for respiratory failure from both the Childrens Healthcare of Atlanta at Egleston (Childrens at Egleston) database and the ELSO registry were reviewed.ResultsThirteen children received ECLS for refractory SA at the Childrens at Egleston from 1986 to 2007. The median age of the children was 10 years (range 1 to 16 years). Patients generally received aggressive use of medical and anaesthetic therapies for SA before cannulation with a median partial pressure of arterial carbon dioxide (PaCO2) of 130 mmHg (range 102 to 186 mmHg) and serum pH 6.89 (range 6.75 to 7.03). The median time of ECLS support was 95 hours (range 42 to 395 hours). All 13 children survived without neurological sequelae. An ELSO registry review found 64 children with SA receiving ECLS during the same time period (51 excluding the Childrens at Egleston cohort). Median age, pre-ECLS PaCO2 and pH were not different in non-Childrens ELSO patients. Overall survival was 60 of 64 (94%) children, including all 13 from the Childrens at Egleston cohort. Survival was not significantly associated with age, pre-ECLS PaCO2, pH, cardiac arrest, mode of cannulation or time on ECLS. Significant neurological complications were noted in 3 of 64 (4%) patients; patients with neurological complications were not significantly more likely to die (P = 0.67).ConclusionsSingle centre and ELSO registry experience provide results of a cohort of children with refractory SA managed with ECLS support. Further study is necessary to determine if use of ECLS in this setting produces better outcomes than careful mechanical ventilation and medical therapy alone.

Respiratory failure caused by tuberculous pneumonia requiring extracorporeal membrane oxygenation

While a common pathogen, Mycobacterium tuberculosis (TB) pneumonitis is only rarely reported as a cause for respiratory failure in developed countries. We report an adolescent with TB pneumonitis and respiratory failure requiring extracorporeal membrane oxygenation (ECMO) with eventual survival. With the incidence of TB rising globally, TB should be suspected and treated as early as possible. ECMO should be considered as a treatment option if conventional ventilatory support is inadequate. ECMO survival with TB pneumonia and anti-TB antimicrobial therapy is possible.

Hair loss after extracorporeal membrane oxygenation.

Objective To discuss the factors associated with hair loss reported after the completion of extracorporeal membrane oxygenation. Design Prospective survey and retrospective chart review. Setting Tertiary care pediatric and adult extracorporeal membrane oxygenation program in a children’s hospital. Patients All patients aged ≥60 months who underwent extracorporeal membrane oxygenation for respiratory or cardiac failure. Interventions Telephone survey of all patients or patient families who met study entry criteria. Measurements and Main Results Twelve extracorporeal membrane oxygenation patients met entry criteria. Nine were contacted and surveyed. Seven children and one adult reported hair loss. One child had no reported hair loss. One patient had a reported hair loss of <10%, three had 25% hair loss, two had 50% hair loss, and two had >50% hair loss. Initial hair loss occurred between 2 wks and 3 months after extracorporeal membrane oxygenation and lasted from 1 to 6 months. No patient sought medical treatment and all reported regrowth of their hair by 6 months after identifying the initial hair loss. Conclusions Hair loss after critical illness is a well-documented phenomenon. Hair loss after extracorporeal membrane oxygenation has not been previously reported. The etiology of the hair loss is probably multifactorial and resolves spontaneously. Patients and families should be educated about hair loss as a potential side effect of extracorporeal membrane oxygenation during their post-extracorporeal membrane oxygenation and discharge teaching.