Extracorporeal membrane oxygenation for nonneonatal respiratory failure

Treatment of Severe Non-Neonatal ARDS in Children with Surfactant and Nitric Oxide in a “PRE-ECMO”-Situation

The use of exogenous surfactant and nitric oxide in neonates has reduced the number of infants requiring ECMO. The purpose of this study was to demonstrate whether these two therapeutic options might reduce the number of over 28 days old children with severe ARDS requiring ECMO, without reducing changes of survival and morbidity. Over a 30 month period all non-neonatal ARDS patients transferred to our institution for ECMO evaluation were treated based on a study-algorithm. If they did not fulfill “fast entry criteria” (paO2< 40 for more than 3 hrs.) we first tried different ventilation, vasodilatation, and hemodynamic strategies for max. 4 hrs. (inv. I/E ratio, HFOV, epoprostenol, high doses norepinephrine. If the 01 did not decrease by< 10, 30-280 mg natural surfactant or 1-20 ppm nitric oxide were treatment options depending on the degree of pulmonary hypertension measured by echocardiography and by mixed venous saturation measurements. It was possible to use NO and surfactant sequentially. The patients had different etiologies of ARDS as near drowning, pneumonia, immunosuppression, and sepsis. If their 01 did not decrease by 10 in 8 hrs. ECMO was installed. Nineteen patients were evaluated, 6 improved with conventional therapy, their 01 decreased without a relapse (mean 01 at begin of the study: 38). Six patients improved with surfactant therapy alone (mean 01: 54), 4 patients improved after surfactant and sequential NO-treatment, 3 patients were initially treated with NO, 1 sequentially with surfactant. One patient did not show any benefit from NO or surfactant and was put on ECMO. Three patients died (withdrawal of life support because of severe brain damage caused by the underlying disease). We could not observe any respiratory related failure. No patient had to be discharged on oxygen. A sophisticated treatment algorithm integrating different modern ARDS treatment options can reduce the number of patients requiring ECMO. We speculate however that these options can only be used effectively in centers involved in ARDS treatment quite frequently and that these centers have to provide ECMO as one of their therapeutic tools.

The Incidence of Acute Kidney Injury and Its Effect on Neonatal and Pediatric Extracorporeal Membrane Oxygenation Outcomes: A Multicenter Report From the Kidney Intervention During Extracorporeal Membrane Oxygenation Study Group

OBJECTIVE

In a population of neonatal and pediatric patients on extracorporeal membrane oxygenation; to describe the prevalence and timing of acute kidney injury utilizing a consensus acute kidney injury definition and investigate the association of acute kidney injury with outcomes (length of extracorporeal membrane oxygenation and mortality).

DESIGN

Multicenter retrospective observational cohort study.

SETTING

Six pediatric extracorporeal membrane oxygenation centers.

PATIENTS

Pediatric patients (age, < 18 yr) on extracorporeal membrane oxygenation at six centers during a period of January 1, 2007, to December 31, 2011.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Complete data were analyzed for 832 patients on extracorporeal membrane oxygenation. Sixty percent of patients had acute kidney injury utilizing the serum creatinine Kidney Disease Improving Global Outcomes criteria (AKI) and 74% had acute kidney injury using the full Kidney Disease Improving Global Outcomes criteria including renal support therapy (AKI). Of those who developed acute kidney injury, it was present at extracorporeal membrane oxygenation initiation in a majority of cases (52% AKI and 65% AKI) and present by 48 hours of extracorporeal membrane oxygenation support in 86% (AKI) and 93% (AKI). When adjusted for patient age, center of support, mode of support, patient complications and preextracorporeal membrane oxygenation pH, the presence of acute kidney injury by either criteria was associated with a significantly longer duration of extracorporeal membrane oxygenation support (AKI, 152 vs 110 hr; AKI, 153 vs 99 hr) and increased adjusted odds of mortality at hospital discharge (AKI: odds ratio, 1.77; 1.22-2.55 and AKI: odds ratio, 2.50; 1.61-3.90). With the addition of renal support therapy to the model, acute kidney injury was associated with a longer duration of extracorporeal membrane oxygenation support (AKI, 149 vs 121 hr) and increased risk of mortality at hospital discharge (AKI: odds ratio, 1.52; 1.04-2.21).

CONCLUSION

Acute kidney injury is present in 60-74% of neonatal-pediatric patients supported on extracorporeal membrane oxygenation and is present by 48 hours of extracorporeal membrane oxygenation support in 86-93% of cases. Acute kidney injury has a significant association with increased duration of extracorporeal membrane oxygenation support and increased adjusted odds of mortality at hospital discharge.

A multicenter international survey of renal supportive therapy during ECMO: the Kidney Intervention During Extracorporeal Membrane Oxygenation (KIDMO) group

Acute kidney injury and fluid overload (FO) are associated with increased mortality in critically ill patients, including the subset supported with extracorporeal membrane oxygenation (ECMO). The indication for and method of application of renal support therapy (RST) during ECMO is largely unknown beyond single-center experiences. The current study uses a survey design to document practice variation regarding RST, including indication, method of interface with the ECMO circuit, and prescribing practices. Sixty-five international ECMO centers (31%) responded to an online electronic survey regarding RST during ECMO. Nearly a quarter of centers (23%) reported using no RST during ECMO. Among those using the therapy, the predominant mode of therapy applied was convection and included slow continuous ultrafiltration and continuous venovenous hemofiltration. The predominant indication for RST was the treatment (43%) or prevention (16%) of FO. Nephrology rather than critical care medicine is reported as the prescribing service in a majority of centers with a significant difference between US centers and non-US centers. The results of this study identify a wide variation in practice regarding RST during ECMO that will offer multiple important avenues for further research by this group and others regarding the interface of RST and ECMO.

Outcomes in children with refractory pneumonia supported with extracorporeal membrane oxygenation

PURPOSE

To review the use of extracorporeal membrane oxygenation (ECMO) in severe paediatric pneumonia and evaluate factors that may affect efficacy of this treatment.

METHODS

Retrospective study of the ECMO database of a tertiary paediatric intensive care unit and chart review of all patients who were managed with ECMO during their treatment for severe pneumonia over a 23-year period. The main outcome measures were survival to hospital discharge, and ICU and hospital length of stay. We compared the groups of culture-positive versus culture-negative pneumonia, venoarterial (VA) versus venovenous (VV) ECMO, community- versus hospital-acquired cases, and cases before and after 2005.

RESULTS

Fifty patients had 52 cases of pneumonia managed with ECMO. Community-acquired cases were sicker with higher oxygenation index (41.5 ± 20.5 versus 26.8 ± 17.8; p = 0.031) and higher inotrope score [20 (5-37.5) versus 7.5 (0-18.8); p = 0.07]. Use of VA compared with VV ECMO was associated with higher inotrope scores [20 (10-50) versus 5 (0-20); p = 0.012]. There was a trend towards improved survival in the VV ECMO group (82.4 versus 62.9 %; p = 0.15). Since 2005, patients have been older [4.7 (1-8) versus 1.25 (0.15-2.8) years; p = 0.008] and survival has improved (88.2 versus 60.0 %; p = 0.039).

CONCLUSIONS

Survival in children with pneumonia requiring ECMO has improved over time and is now 90 % in the modern era. Risk factors for death include performing a circuit change [odds ratio (OR) 5.0; 95 % confidence interval (CI) 1.02-24.41; p = 0.047] and use of continuous renal replacement therapy (OR 4.2; 95 % CI 1.13-15.59; p = 0.032).

Trends in and perspectives on extracorporeal membrane oxygenation for severe adult respiratory failure

Various approaches such as ventilator management involving lung-protective ventilation, corticosteroids, prone positioning, and nitric oxide have failed to maintain sufficient lung oxygenation or appropriate ventilation competence in very severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) has been aggressively introduced for such patients, although in only a few institutions. The clinical usefulness of ECMO in a large-scale multicenter study (CESAR trial, 2009) and continued development/improvement of ECMO devices have facilitated performance of ECMO, with further increase in the number of institutions adopting ECMO therapy. Clinical usefulness of ECMO was documented in many cases of severe ARDS secondary to influenza A (H1N1) 2009 infection. ECMO requires establishment of an appropriate management system to minimize fatal complications (e.g., hemorrhage), which requires a multidisciplinary team. This, in combination with a new technique, interventional lung assist, will further extend the indications for ECMO. ECMO can be expected to gain importance as a respiratory support technique.

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 PaO(2)/FIO(2) 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.

Survival and renal function in pediatric patients following extracorporeal life support with hemofiltration

OBJECTIVE: To determine variables associated with survival in pediatric patients treated with hemofiltration while receiving extracorporeal life support and to determine the probability for recovery of renal function among survivors. DESIGN: Retrospective database analysis. SETTING: University of Michigan pediatric nephrology database. PATIENTS: All pediatric patients treated with continuous hemofiltration while on extracorporeal life support at the University of Michigan between January 1990 and May 1999. A pediatric patient was defined as any child between birth and 18 yrs of age, including children treated in both the pediatric intensive care unit and neonatal intensive care unit. Indications for extracorporeal life support included both cardiac and pulmonary failure. INTERVENTIONS: Data analysis of patients who were treated with hemofiltration while on extracorporeal life support. Hemofiltration includes both ultrafiltration and hemofiltration with countercurrent dialysis. MEASUREMENTS AND MAIN RESULTS: Thirty-five patients with a mean age of 39 +/- 65 months (median, 3 months) underwent hemofiltration while on extracorporeal life support. Forty-three percent survived to hospital discharge (95% CI, 26%-60%). All deaths occurred in the intensive care unit. Recovery of renal function occurred in 93% of survivors (95% CI, 79%-108%). Mean duration of hemofiltration in survivors, including time during and after extracorporeal life support, was 9 +/- 6 days. All nonsurvivors were on renal replacement therapy at the time of death. In this analysis, decreased survival was significantly associated with the use of vasopressor infusions (p =.01) and the presence of complications (p =.006). Vasopressor infusions were required in 89% of patients, and 37% of patients experienced complications. CONCLUSIONS: In patients receiving hemofiltration while on extracorporeal life support, survival is comparable to that reported in other extracorporeal life support or hemofiltration populations. Decreased survival in these patients may be associated with the use of vasopressor infusions and the occurrence of complications. Recovery of renal function occurs in most survivors.

Venovenous versus venoarterial extracorporeal life support for pediatric respiratory failure: are there differences in survival and acute complications?

OBJECTIVES

To examine the Extracorporeal Life Support Organization (ELSO) registry database of infants and children with acute respiratory failure to compare outcome and complications of venovenous (VV) vs. venoarterial (VA) Extracorporeal Life Support (ECLS).

DESIGN

Retrospective cohort study.

SETTING

ELSO registry for pediatric pulmonary support.

PATIENTS

All nonneonatal pediatric pulmonary support ECLS cases treated at U.S. centers and reported to the ELSO registry as of July 1997. Patients were excluded if they had one or more of the following diagnoses: hematologic-oncologic, cardiac, abdominal surgical, burn, metabolic, airway, or immunodeficiency disorder.

INTERVENTIONS

Venoarterial or venovenous extracorporeal life support for severe pulmonary failure.

MEASUREMENTS AND MAIN RESULTS

From 1986 to June of 1997, 763 pediatric patients met the inclusion criteria. Overall, 595 were initially managed with VA bypass, and 168 with VV bypass. The VA group was younger (mean +/- SD, 26.1+/-42.2 months for VA vs. 63.5+/-68.7 months for VV) and smaller (11.8+/-15.1 kg vs. 22.9+/-23.8 kg) (p<.001). There were no differences between groups in number of days on mechanical ventilation before ECLS, number of hours on ECLS, or number of hours on mechanical ventilation post-ECLS in survivors. Mean pH and Paco2 values, positive end-expiratory pressure, and mean airway pressure just before placing the patient on ECLS were also similar. VA-treated patients had higher Fio2 requirements (p = .034), lower Pao2 (p = .047), and lower Pao2/Fio2 ratio (p = .014) just before cannulation. There was a trend of higher peak inspiratory pressure in VA-treated patients (p = .053). Overall, survival rate was not different for the two groups (55.8% for VA vs. 60.1% for VV; p = .33). Central nervous system complications were not different between the two groups. Examination of the same variables was then conducted after dividing the patients into four subgroups. There were no significant differences in survival or complications during bypass between VV and VA modes of ECLS in any subgroup. Stepwise logistic regression modeling was performed to control for variables associated with the outcome survival for VV and VA-treated groups, and variables measured before bypass were identified as being associated with improved survival. There was a trend of improved survival in the VV-treated patients (p = .12).

CONCLUSIONS

Overall survival of pediatric patients with acute respiratory failure supported by VA or VV ECLS was comparable. A randomized clinical trial may be useful in clarifying these observations.

Adapting prognostic respiratory variables of ARDS in children to small-scale community needs

PURPOSE

The clinical literature on the incidence and subsequent mortality of adult respiratory distress syndrome (ARDS) has come primarily from the experiences of large tertiary referral centers, particularly in Western Europe and North America. Consequently, very little has been published on the incidence, management, and outcome of ARDS in smaller community-based intensive care units. We aimed to delineate early clinical respiratory predictors of death in children with ARDS on the modest scale of a community hospital.

MATERIALS AND METHODS

A retrospective chart review of children with ARDS needing conventional mechanical ventilation admitted to our pediatric intensive care unit from 1984 to 1997. The diagnosis of ARDS was based on acute onset of diffuse, bilateral pulmonary infiltrates of noncardiac origin and severe hypoxemia defined by partial pressure of oxygen <200 mm Hg during positive end-expiratory pressure (PEEP) of 6 cm H2O or greater for a minimum of 24 hours. Demographic, clinical, and physiological data including PaO2/ FIO2, A-aDo2, and ventilation index were retrieved.

RESULTS

Fifty-six children with ARDS aged 8 +/- 5.5 years (range, 50 days to 21 years) were identified. The mortality rate was 50%. Early predictors of death included the peak inspiratory pressure (PIP), ventilation index, and PEEP on the third day after diagnosis: Nonsurvivors had significantly higher PIP (35.3 +/- 10.5 cm H2O vs 44.4 +/- 10.7 cm H2O, P < .001), PEEP (8 +/- 2.8 cm H2O vs 10.7.0 +/- 3.5 cm H2O, P < .01), and ventilation index (49.14 +/- 20.4 mm Hg x cm H2O/minute vs 61.6 +/- 51.1 mm Hg cm H2O/minute) than survivors. In contrast, PAO2/FIO2 and A-a DO2 were capable of predicting outcome by day 5 and thereafter.

CONCLUSIONS

A small-scale mortality outcome for ARDS is comparable to large tertiary referral institutions. The PIP, PEEP, and ventilation index are valuable for predicting outcome in ARDS by the third day of conventional therapy. The development of a local risk profile may assist in decision-making of early application of supportive therapies in this population.

[Current aspects of acute respiratory distress syndrome in children]

Acute respiratory distress syndrome (ARDS) is a frequent condition in pediatric intensive care units. The mortality remains high despite advances in conventional mechanical ventilation and aetiological treatment. Several animal studies have documented lung injury during mechanical ventilation with high tidal volume, and clinical investigations have shown that in human ARDS, most ventilation is distributed to the small areas of remaining aerated lung resulting in overdistension of these areas and lung injury ("baby lung" theory). Nevertheless the usefulness of extrapulmonary gas exchange remains much debated. New ventilatory strategies have been developed in order to reduce ventilator-induced lung injury and to improve systemic oxygenation but multicentric randomized clinical trials are needed before these strategies can be validated.

Principles and Practice of Venovenous Extracorporeal Membrane Oxygenation

Over the past several years, the use of venovenous extracorporeal membrane oxygenation (ECMO) has increased. The primary advantage of venovenous (VV) over venoarterial (VA) ECMO is preservation of the carotid artery. Its primary disadvantage is that it does not provide circulatory support. While VV ECMO is technically similar to VA ECMO, clinical application of VV ECMO is quite different from VA ECMO. Recent clinical data show that VV ECMO is safe and effective. The purpose of this review is to discuss these differences between VV and VA ECMO, to review the various forms of VV ECMO, and finally to offer recommendations on the safe clinical use of VV ECMO.

Mechanical ventilation and arterial blood gas measurements 24 hours postextracorporeal life support for survivors of pediatric respiratory failure

OBJECTIVE

To summarize our institutional experience concerning mechanical ventilation support and blood gas measurements in the 24-hr period following extracorporeal life support (ECLS) for pediatric acute respiratory failure.

DESIGN

Descriptive study.

SETTING

A tertiary pediatric referral center.

PATIENTS

Children aged 1 month to 18 yrs treated with ECLS for acute respiratory failure at University of Michigan Hospitals from November 1982 to June 1993. All patients aged 1 month to 18 yrs who received ECLS for acute respiratory failure were included. Patients who received ECLS primarily for cardiac support or who had a diagnosis of congenital gastrointestinal malformation (i.e. congenital diaphragmatic hernia) were excluded.

INTERVENTIONS

ECLS for severe pediatric respiratory failure.

MEASUREMENTS AND MAIN RESULTS

Forty-nine children were treated at our center with ECLS for acute respiratory failure 36 (73%) survived. Ventilator settings immediately after decannulation from ECLS for survivors were as follows: FIO2 0.53 +/- 0.18 (SD); intermittent mandatory ventilation (IMV) 29.6 +/- 1.18 breaths/min, positive end-expiratory pressure 5.3 +/- 1.6 cm H2O, mean airway pressure 12.6 +/- 2.9 cm H2O, and peak inspiratory pressure 31.7 +/- 5.5 cm H2O. Arterial blood gas measurements at decannulation were PaO2 89.4 +/- 30.9 torr (11.9 +/- 4.1 kPa), PaCO2 43.7 +/- 9.7 torr (5.8 +/- 1.3 kPa), and pH 7.39 +/- 0.07. Twenty-four hours after decannulation, ventilator settings and arterial blood gas measurements were as follows: FIO2 0.42 +/- 0.14, IMV 27.4 +/- 13.5 breaths/min, positive end-expiratory pressure 5.2 +/- 1.6 cm H2O, mean airway pressure 12.0 +/- 3.4 cm H2O, peak inspiratory pressure 31.1 +/- 6.5 cm H2O, PaO2 77.0 +/- 16.9 torr (10.3 +/- 2.3 kPa), PaCO2 44.9 +/- 8.4 torr (6.0 +/- 1.1 kPa), and pH 7.40 +/- 0.07. Variables associated with oxygenation status (P[A-a]O2) and mean airway pressure (oxygenation index) improved during the immediate 24-hr period postbypass (p < .05).

CONCLUSIONS

Successful decannulation from ECLS for > 24 hrs resulted in long-term survival in 97% (36/37) of children. Ventilator parameters and arterial blood gas measurements during the 24-hr period following bypass have been described for this population. Such conventional support may indicate safe levels of oxygen and mechanical ventilation pressures for the postbypass recovering lung.

Benefits of extracorporeal membrane oxygenation for hydrocarbon pneumonitis

OBJECTIVE

To review the therapeutic benefits of extracorporeal membrane oxygenation for the management of hydrocarbon pneumonitis.

METHODS

A search of the medical literature was conducted through Medline and the bibliographies of relevant articles and a search of patient databases maintained by the Extracorporeal Life Support Organization and the American Association of Poison Control Centers was performed. All articles and case reports on the use of extracorporeal membrane oxygenation in patients with hydrocarbon pneumonitis were selected. The data were abstracted without judgments about study design.

RESULTS

There is some evidence that pulmonary parenchymal tissue can recover from hydrocarbon pneumonitis, but the degree of injury and recovery are variable. In the Extracorporeal Life Support Organization Registry 19 children with hydrocarbon pneumonitis were treated with extracorporeal membrane oxygenation during 1985 to 1994 and 68% survived compared to the 52% overall survival of 883 pediatric cases who had a diagnosis of a respiratory condition. A review of the American Association of Poison Control Centers data for 1993 and 1994 identified five cases of hydrocarbon pneumonitis in which extracorporeal membrane oxygenation was used and two survived. There are two full case descriptions in the literature with both children surviving, but one child developed persistent moderate left hemiparesis and seizure activity.

CONCLUSIONS

The need for extracorporeal membrane oxygenation is rare owing to the generally good outcome of most cases of hydrocarbon ingestions and pneumonitis. Only with further research on the nature and clinical course of severe hydrocarbon pneumonitis, refinement of extracorporeal membrane oxygenation criteria, and evaluation of alternative therapies, will the benefits of extracorporeal membrane oxygenation be better defined.

Pediatric ECMO for pulmonary support: experience from 12 cases

Extracorporeal membrane oxygenation (ECMO), which can be described as treatment with a modified heart-lung machine over a prolonged period of time, is used to support patients with life-threatening but potentially reversible lung failure. ECMO by itself does not cure the patient but gives the lungs a chance to rest while awaiting spontaneous or therapeutic healing. The method is well documented in the neonatal age group. In the non-neonatal age group, however, experience is less extensive. This report of the initial result from our hospital with 12 non-neonatal pediatric cases shows high survival and low morbidity. Nine of the 12 patients were able to be weaned from ECMO (75% survival) and 8 of these 9 patients were long-term survivors. Medium time on the ventilator after discontinuation of ECMO was 4 days. At follow-up, all long-term survivors had no signs of neurological or pulmonary sequelae. These encouraging results point to the fact that ECMO should be considered more often in cases of life-threatening but potentially reversible pulmonary failure.

Sonographically guided cannula positioning for extracorporeal membrane oxygenation

Drainage problems due to catheter malpositioning are acutely life-threatening in patients undergoing extracorporeal membrane oxygenation. In order to reduce these complications we introduced sonographically guided catheter positioning. We compare the outcome in a group of patients with blind cannula positioning to that in a group with sonographically guided catheter positioning. Our results show that neonates and young infants especially are at high risk of drainage problems due to catheter malposition and that their outcome could be markedly improved by introducing sonographically guided cannula insertion.

Novel therapies for acute respiratory failure

Mortality in acute respiratory failure in the non-neonatal pediatric patient has not changed substantially in 20 years, despite advances and refinements in conventional therapeutic strategies and technology. A host of innovative therapies are currently in various stages of investigation, including high frequency ventilation, pressure control ventilation, permissive hypercapnia, extracorporeal membrane oxygenation, exogenous surfactant administration, inhaled nitric oxide, and liquid ventilation. While none of these therapies has yet been prospectively studied in non-neonatal pediatric patients, all show much promise by virtue of their emphasis on either directly addressing pathophysiologic derangements associated with acute respiratory failure or by reducing the complications associated with conventional therapy.

Extracorporeal life support for severe pediatric respiratory failure: an updated experience 1991-1993

OBJECTIVE

The purpose of this study was to examine our recent experience with children who had acute respiratory failure managed with extracorporeal life support (ECLS) from 1991 to 1993, to determine whether a change in survival rate had occurred in comparison with our previous experience.

DESIGN

Historic and prospective cohort study.

SETTING

A tertiary pediatric referral center.

PATIENTS

All non-neonatal pediatric patients treated with ECLS for severe, life-threatening respiratory failure were examined. Overall, 25 patients have been managed with this life-support technique in the past 28 months. Eighty-four percent (21/25) were transferred to our medical center because of failure of conventional mechanical ventilation therapy. Descriptive data of the recent cohort were as follows (mean +/- SD): age 60 +/- 75 months, weight 23.6 +/- 24.8 kg, and male gender 44%. Duration of intubation before ECLS was 5.8 +/- 2.7 days. Arterial blood gas values and ventilator settings immediately before ECLS were as follows: fraction of inspired oxygen, 0.98 +/- 0.08; mean airway pressure, 21.6 +/- 6.2 cm H2O; peak inspiratory pressure, 45.5 +/- 9.6 cm H2O; positive end-expiratory pressure, 11.0 +/- 4.3 cm H2O; partial pressure of oxygen (arterial), 56 +/- 20 mm Hg (7.4 +/- 2.7 kilopascals); partial pressure of carbon dioxide (arterial), 46 +/- 17 mm Hg (6.1 +/- 2.3 kPa); and estimated alveolar-arterial oxygen tension difference, 572 +/- 81 mm Hg (76.3 +/- 10.8 kPa). Mean duration of ECLS was 373 +/- 259 hours. Of 25 recently treated patients, 22 (88%) survived their life-threatening respiratory illness to be discharged home; this represented a statistically improved survival rate in comparison with the 58% survival rate previously reported by us for similar patients (p < 0.05). Comparisons of arterial blood gas and mechanical ventilation-related variables measured 24 hours before and again immediately before bypass were similar in the two cohorts with the exception of higher mean partial pressure of carbon dioxide (arterial) 24 hours before bypass in the recent treatment group. For our entire experience, younger age groups had greater survival rates; 100% of infants less than 1 year of age survived.

CONCLUSIONS

Treatment with ECLS is an evolving pulmonary rescue therapy with an 88% survival rate in our recent experience. The survival rate has improved to levels that may not greatly improve in the near future, especially for patients less than 1 year of age. Better patient selection or improved management strategies or both may be responsible for the improved patient outcome.

Extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation has now evolved into standard therapy for patients unresponsive to conventional ventilatory and pharmacological support. This article presents a clinical review of extracorporeal life support and its application to neonatal and pediatric patients as well as children requiring circulatory support after open heart surgery.

Predictors of outcome of severe respiratory syncytial virus-associated respiratory failure treated with extracorporeal membrane oxygenation

OBJECTIVE

To examine the Extracorporeal Life Support Organization registry data base for all infants and children with respiratory syncytial virus-associated respiratory failure managed with extracorporeal life support, to delineate predictors of outcome.

DESIGN

Retrospective cohort study.

SETTING

Extracorporeal Life Support Organization data registry.

PATIENTS

All pediatric patients treated in the United States with extracorporeal life support for severe pediatric respiratory syncytial virus-associated respiratory failure reported to the registry, from 1982 through June 1992.

INTERVENTIONS

Venoarterial or venovenous extracorporeal life support.

MEASUREMENTS AND MAIN RESULTS

As of June 1992, fifty-three pediatric patients meeting study entry criteria were reported to the Pediatric Respiratory Failure Registry (n = 412) as having received extracorporeal membrane oxygenation (ECMO) for severe respiratory syncytial virus infection with pulmonary failure. Forty-nine percent (26/53) were successfully managed and survived to hospital discharge. The mean patient age was 5.0 +/- 8.6 months. Duration of mechanical ventilation before institution of extracorporeal life support was 8.1 +/- 6.2 days. Multivariate logistic regression analysis found four variables to be associated with patient nonsurvival at the p < 0.05 level: male gender, longer duration of mechanical ventilation before ECMO, higher peak inspiratory pressure, and lower ratio of arterial oxygen tension to fraction of inspired oxygen. Era of treatment was not associated with outcome. Receiver operator characteristic curve analysis of this multivariate model resulted in cutoff points of r = 0.5 and 0.1 that resulted in 92% sensitivity and 81% specificity (false-positive ratio 19%) and 96% sensitivity and 73% specificity (false-positive ratio 27%), respectively.

CONCLUSIONS

Predictors of outcome of severe respiratory failure caused by respiratory syncytial virus infection managed with ECMO exist, and multivariate predictive models with high sensitivity and low false-positive risk are possible. Similar mathematical models may be helpful in establishing criteria for future trials of ECMO versus conventional respiratory support.

Uses of extracorporeal membrane oxygenation in nonneonatal respiratory patients. An update

Neonatal extracorporeal membrane oxygenation (ECMO) has progressed rapidly from the experimental stage to a standard of care for certain infants who fail to respond to maximal conventional management. A broad diagnostic group of nonneonatal patients has now been supported by several different modes of ECMO with encouraging results. Selection criteria for nonneonatal patients that differ from those used for neonatal patients are emerging. Prospective randomized clinical trials are needed.

Effects of synchronous pulsatile extracorporeal membrane oxygenation in an endotoxin-induced shock model: an experimental study

A synchronous pulsatile venoarterial device for extracorporeal membrane oxygenation (ECMO) was designed to accomplish more effective circulatory support for neonates. The effect of this device was studied using an endotoxin-induced shock model, compared with conventional nonpulsatile ECMO. Twenty puppies weighing 1.6 to 4.0 kg were given endotoxin (5 mg/kg) intravenously. Thirty minutes after the administration of endotoxin, 10 were placed on pulsatile ECMO, and the others were placed on nonpulsatile ECMO, and they were studied for an additional 180 min. Peak blood pressure, arterial pH, base excess, and renal blood flow were significantly higher in the pulsatile group than in the nonpulsatile group. Serum lactate and serum noradrenaline were significantly lower in the pulsatile group than in the nonpulsatile group. These results indicate that pulsatile ECMO may provide more effective cardiopulmonary support in the treatment of neonates with serious circulatory failure that has failed to be supported by nonpulsatile ECMO.

Treatment of acute pulmonary failure with extracorporeal support: 100% survival in a pediatric population

Since February 1990, five children, aged 10 days to 6.5 years, were treated with extracorporeal lung support at our hospital for acute, unrelenting pulmonary failure. Two had viral pneumonia: one with respiratory syncytial virus (RSV) bronchiolitis, and one with herpes simplex virus pneumonia, encephalitis, and disseminated intravascular coagulation. One presented with a febrile illness followed by a pulmonary hemorrhage. Two patients had adult respiratory distress syndrome (ARDS) complicating severe systemic illnesses, toxic epidermal necrolysis in one and cat scratch disease with encephalitis in the other. All children had diffuse parenchymal lung disease by chest x-ray. On maximum medical management all patients were developing carbon dioxide retention and progressive hypoxemia, exceeding previously established NIH study criteria for extracorporeal treatment. Three children (10 days, 2 months, 13 months) were placed on venoarterial support and two children (20 months and 6.5 years) were placed on venovenous extracorporeal support (ECCO2R). Three of the five had open lung biopsies performed, which showed findings consistent with a moderate to severe cellular phase of ARDS. No viral inclusions were found in the patient with RSV infection. One hundred percent immediate survival was achieved in this patient population. Average duration of support was 330 hours (range, 89 to 840). Following completion of extracorporeal support, all children were successfully weaned from the ventilator with an average time to extubation of 23.2 days (range, 2 to 58 days). One child died of congestive heart failure following palliative surgery for a complex noncyanotic congenital cardiac lesion 35 days after successfully weaning from extracorporeal support for an acute febrile illness and pulmonary hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)