Venovenous Extracorporeal Life Support Research Articles

Hematological changes during short-term tidal flow extracorporeal life support

Various methods exist in the clinical practice of long-term venovenous (VV) extracorporeal life support (ECLS). Among the clinical techniques used are single venous access with a dual-lumen catheter, and cannulation of the jugular and femoral veins. Tidal flow VV ECLS uses a single-lumen catheter to achieve both venous drainage and arterialized reinfusion through a series of tubing occluders that are automated by a pump. A single venous occluder tidal flow system with a 15 Fr single-lumen cannula (n = 6) and passive filling M pump was compared to a conventional 14 Fr dual-lumen cannula (n = 7) and roller pump for four hours of VV ECLS. The changes in platelet count and plasma-free hemoglobin (pHgb) were compared. The results showed a decline in platelet counts typical of ECLS in both groups that were not significantly different from each other. A small elevation in pHgb did not rise above normal clinical levels of 15 mg/dL in either group after four hours of ECLS. Some recirculation was observed and needs to be addressed in future studies. Single occluder tidal flow ECLS may be feasible and efficacious for long-term application once recirculation is resolved and the system evaluated for long-term support.

Preliminary experiment with a newly developed double balloon, double lumen catheter for extracorporeal life support vascular access.

Recently, venovenous extracorporeal life support (VVECLS) using a double lumen catheter has been clinically used to avoid neurologic complications in the treatment of respiratory failure for neonates. However, recirculation, which is a limiting factor for oxygen delivery, still exists, and thus it does not contribute to oxygenation of the patient. We developed a newly designed double lumen catheter with a double balloon (DBDL) catheter for ECLS vascular access and performed two animal preliminary experiments in normal and hypoxic dog models (normal ventilation and one lung ventilation experiments) to investigate whether the DBDL catheter could prevent recirculation and maintain oxygen delivery to systemic circulation. The DBDL catheter (JCT Co., Hiroshima, Japan) of 15 Fr was fabricated from silicone. It consists of two lumens for drainage and return of blood with two balloons (distal and proximal balloons) that prevent oxygenated blood mixing with unoxygenated blood. VVECLS using a DBDL catheter was performed in 13 mongrel dogs (8 dogs for normal ventilation experiment weighing 12.9 +/- 1.6 kg [mean +/- SD], 5 dogs for one lung ventilation experiment weighing 16.6 +/- 2.5 kg [mean +/- SD]) under anesthesia in the two experiments. The bypass flow ranged from 10-40 ml/kg per minute in the normal ventilation experiment. VVECLS in the one lung ventilation experiment was performed with maximal bypass flow for 6 hours (ranged from 25.2 +/- 8.0-28.3 +/- 8.7 ml/kg per minute at balloon inflation and deflation). Recirculation and oxygen transfer of artificial lung with or without balloon inflation during VVECLS were studied. Recirculation decreased with balloon inflation at varied bypass flows during VVECLS in the normal ventilation experiment (varied from 1.5 +/- 14.6-12.8 +/- 16.7%) and for 6 hours after VVECLS initiation in the one lung ventilation experiment (varied from 12.2 +/- 12.2-19.2 +/- 6.5%). In particular, the values at 3 and 6 hours were significantly lower than that of balloon deflation in the one lung ventilation experiment. The difference in O2 content between inlet and outlet in the artificial lung with balloon inflation was significantly higher than that of balloon deflation (varied from 3.7 +/- 1.8-4.8 +/- 1.9 ml/dl, p < 0.05) at the bypass flow of 10-30 ml/kg per minute in the normal ventilation experiment and at 5 hours after VVECLS initiation in the one lung ventilation experiment (varied from 10.6 +/- 1.6-11.7 +/- 1.8 ml/dl). The blood gas analysis of systemic circulation with balloon inflation revealed that the values of PaO2 (varied from 83.8 +/- 11.4-96.9 +/- 23.4 mm Hg) and PaCO2 (37.7 +/- 9.2-40.4 +/- 11.8 mm Hg) were higher and lower, respectively, compared with balloon deflation. In particular, PaO2 level was significantly higher than that of the preECLS value at the bypass flow of 20-40 ml/kg per minute (varied from 83.8 +/- 11.4-96.9 +/- 23.4 mm Hg, p < 0.05). In the one lung ventilation experiment, systemic PaO2 and PaCO2 levels at balloon inflation were higher and lower, respectively, compared with balloon deflation during VVECLS for 6 hours. At balloon inflation, the value of PaO2 at 6 hours after VVECLS initiation was significantly higher than that at balloon deflation. A newly designed DBDL catheter for ECLS vascular access successfully reduced recirculation and maintained oxygen delivery to systemic circulation during VVECLS. These results suggest that a high bypass flow may not be necessarily required in terms of oxygen delivery to systemic circulation when the DBDL catheter was used as an ECLS vascular access.

Percutaneous cannulation for pediatric venovenous extracorporeal life support

Background/Purpose: The objective of this study was to show the safety and efficacy of a method of percutaneous cannulation for venovenous extracorporeal life support (ECLS) access in nonneonatal (>10 kg) pediatric patients. Methods: Between June 1992 and October 1998, 26 pediatric patients (age range, 3 to 17 years; weight range, 19 to 100 kg) underwent attempted percutaneous cannulation for venovenous ECLS at our institution. Venous drainage access was attempted using a modified Seldinger technique via the right internal jugular vein (RIJ, n = 22) or right femoral vein (RFV, n = 4). Reinfusion access was attempted via the RFV (n = 19), RIJ (n = 4), or left femoral vein (n = 3). Results: The percutaneous technique was successful in 24 of 26 patients (92.3%). Maximum blood flow during ECLS was 80.1 ± 30.0 mL/kg/min, generating a postmembrane lung outlet pressure of 138 ± 54.8 mm Hg. Adequate gas exchange was achieved in all patients, and survival to discharge was 79.2%. There was no procedure-related mortality. Complications potentially related to the percutaneous technique included RIJ thrombosis (n = 1) detected after decannulation and cannula site bleeding (n = 3). Conclusion: Percutaneous access may be used safely and effectively for venovenous ECLS in pediatric patients. J Pediatr Surg 35:943-947. Copyright © 2000 by W.B. Saunders Company.

Venovenous Extracorporeal Life Support Via Percutaneous Cannulation in 94 Patients

The objective of this study was to demonstrate the safety and utility of a method of percutaneous access for cannulation of adult patients for venovenous extracorporeal life support (ECLS). A retrospective review of a patient series. A surgical ICU at a university teaching hospital. The study group consisted of 94 adults > 17 years old with respiratory failure who were placed on venovenous ECLS by means of percutaneous cannulation. The cannulation of the internal jugular and femoral veins (FVs) using the Seldinger technique for venovenous ECLS. Between May 1992 and November 1997, we performed percutaneous cannulation for venovenous ECLS in 94 adult patients with respiratory failure. The mean (+/- SD) age was 36.1+/-12.7 years old (range, 17 to 65 years). The mean (+/-SD) weight was 80.7+/-22.3 kg (range, 36 to 156 kg). The right internal jugular vein (RIJV) was used for venous drainage access in all but four cases. The right FV (n = 86), the left FV (n = 3), or the RIJV (n = 4) was utilized for venous reinfusion. The maximum blood flow (+/-SD) during ECLS was 57.6+/-17.5 mL/kg/min (range, 22.4 to 127.8 mL/kg/min), with a postmembrane outlet pressure (+/-SD) of 146+/-43 mm Hg (range, 56 to 258 mm Hg) at the maximum flow rate. There were 11 unsuccessful percutaneous cannulation attempts. In three patients (3%), the complications consisted of arterial injury requiring operative cutdown and repair. In six patients (6%), cannula-site bleeding required pursestring suture reinforcement of the cannula site. One patient died from the perforation of the superior vena cava during cannulation. Based on these data, we conclude that percutaneous cannulation may be utilized to provide venovenous ECLS in adults.

A prospective comparison of atrio-femoral and femoro-atrial flow in adult venovenous extracorporeal life support

Introduction: In the United States, venovenous extracorporeal life support has traditionally been performed with atrial drainage and femoral reinfusion (atrio-femoral flow). Although flow reversal (femoro-atrial flow) may alter recirculation and extracorporeal flow, no direct comparison of these 2 modes has been undertaken. Objective: Our goal was to prospectively compare atrio-femoral and femoro-atrial flow in adult venovenous extracorporeal life support for respiratory failure. Methods: A modified bridge enabling conversion between atrio-femoral and femoro-atrial flow was incorporated in the extracorporeal circuit. Bypass was initiated in the direction that provided the highest pulmonary arterial mixed venous oxygen saturation, and the following measurements were taken: (1) maximum extracorporeal flow, (2) highest achievable pulmonary arterial mixed venous oxygen saturation, and (3) flow required to maintain the same pulmonary arterial mixed venous oxygen saturation in both directions. Flow direction was then reversed, and the measurements were repeated. Data were compared with paired t tests and are presented as mean ± standard deviation. Results: Ten patients were studied, and 9 were included in the data analysis. Femoro-atrial bypass provided (1) higher maximal extracorporeal flow (femoro-atrial flow = 55.6 ± 9.8 mL/kg per minute, atrio-femoral flow = 51.1 ± 11.1 mL/kg per minute; P = .04) and (2) higher pulmonary arterial mixed venous oxygen saturation (femoro-atrial flow = 89.9% ± 6.6%, atrio-femoral flow = 83.2% ± 4.2%; P = .006); (3) furthermore, it required less flow to maintain an equivalent pulmonary arterial mixed venous oxygen saturation (femoro-atrial flow = 37.0 ± 12.2 mL/kg per minute, atrio-femoral flow = 46.4 ± 8.8 mL/kg per minute; P = .04). Conclusions: During venovenous extracorporeal life support, femoro-atrial bypass provided higher maximal extracorporeal flow, higher pulmonary arterial mixed venous oxygen saturation, and required comparatively less flow to maintain an equivalent mixed venous oxygen saturation than did atrio-femoral bypass. (J Thorac Cardiovasc Surg 1998;116:628-32)

Liquid ventilation in an infant with pulmonary alveolar proteinosis

Partial liquid ventilation (PLV) has been applied in various pulmonary diseases. We describe the use of partial liquid ventilation as a lavage method following normal saline (NS) lavage in an infant with pulmonary alveolar proteinosis (PAP) and severe hypoxemia. A 6 weeks old 3.4 kg former 36 weeks gestation boy on supplemental oxygen was transferred to our NICU with persistent tachypnea, dry cough, and increasing oxygen requirements. A lingular open lung biopsy revealed PAP. He developed progressive respiratory failure requiring ventilatory support, necessitating conventional NS lavage, followed by lung lavage with perflubron (LiquiVent; Alliance Pharmaceutical Corp. and Hoechst Marion Roussel) while on venovenous extracorporeal life support (ECLS). Lung lavage with NS and perflubron yielded minimal cloudy effluent. Gas exchange and pulmonary function deteriorated following NS lavage and attempts to discontinue ECLS were poorly tolerated. In contrast, tidal volume, PaO2, and pulmonary compliance increased after PLV, while the (A-a) DO2 decreased to a point where ECLS was no longer required. Once perflubron was added repeatedly to the ventilator circuit to correct for evaporation over the 4 days of PLV. Cardiovascular status remained stable for several days; however, eventually he required reinitiation of ECLS and more mechanical ventilatory support with each trial off ECLS. He was maintained on high pressures and FiO2 without any possibility to wean him from mechanical ventilation. Life support was withdrawn 1 month after admission. The survival from PAP in infants remains dismal, even with total lung NS lavage. While both NS and perflubron lavage in this patient were not effective in removing the proteinaceous alveolar debris, PLV following NS lavage was associated with an improvement in gas exchange and lung compliance. Pediatr Pulmonol. 1998; 26:283–286. © 1998 Wiley-Liss, Inc.

Percutaneous access for venovenous extracorporeal life support in neonates

Background: Although percutaneous cannulation has been previously described in adult and pediatric patients older than 3 years, its use in neonates for venovenous extracorporeal life support (ECLS) has not been previously described. Methods: Twenty neonates of weight 3.4 ± 0.6 kg (range, 2.3 to 4.9 kg.) with severe respiratory failure (meconium aspiration syndrome, persistent pulmonary hypertension of the newborn, sepsis) were managed with double-lumen venovenous ECLS. Percutaneous access via the right internal jugular (RIJ) vein with a 12F (n = 13) or 15F (n = 7) double-lumen ECLS cannula was obtained via a modified Seldinger technique. RIJ access was specifically obtained 2 to 3 cm above the clavicle with a 21-gauge needle and a 0.018-in guide wire followed by a technique that allowed insertion of the larger cannula guide wire. Decannulation simply involved removal of the cannula with hemostasis obtained by direct pressure. Results: Percutaneous cannulation was performed without difficulty in 11 infants. Conversion to an open technique for cannula placement was required in four patients early in our experience because percutaneous access to the RIJ with the 0.018-inch guide wire could not be achieved, and in one neonate because the 15F cannula could not be advanced into the RIJ and resulted in laceration of the vein. Inability to achieve RIJ access also led to use of an “exposure-assisted” percutaneous procedure in four patients later in our experience. Complications included a pneumothorax identified on chest radiograph 18 hours after cannulation in one infant and partial thrombotic occlusion of the cannula requiring a change over a guide wire in another. There were no problems associated with decannulation. Conclusions: This is the first description of percutaneous cannulation in neonates for venovenous ECLS. In the authors' early experience, percutaneous access using a 12F double lumen venovenous cannula may be efficiently performed especially in patients >3.0 kg in weight and has the potential for simplifying and reducing the cost of the ECLS technique.

Venovenous Extracorporeal Life Support for Patients After Cardiotomy

Pulmonary edema and acute lung injury are common sequelae after cardiopulmonary bypass. Increased ventilatory support improves gas exchange, but may compromise ventricular function. From July 1994 to February 1997, nine patients were supported with veno-venous (V-V) extracorporeal life support (ECLS) for post cardiotomy respiratory failure. The mean age was 53 +/- 13 years (range: 37-80 years), and eight (89%) were men. Pre-operatively, five of nine (56%) were intubated, three (33%) were supported with an intra-aortic balloon pump, and five (56%) were on veno-arterial ECLS. Four patients were post left ventricular assist device (LVAD) implantation, one each after resection of an aortic aneurysm, mitral valve replacement and bypass grafting, aortic valve replacement, and pulmonary embolectomy and heart transplantation. Mean duration of support was 2 +/- 1 days (range: 1-4 days). Patients were intubated for a mean of 2 +/- 22 days (range: 4-71 days). One patient (11%) required mediastinal re-exploration secondary to bleeding, two patients underwent hemodialysis or ultrafiltration, and seven (77%) developed bacterial pneumonia. All patients were weaned from ECLS. Six patients (67%) survived to hospital discharge. Cause of death was multiple organ failure in two patients; one died from respiratory failure. V-V ECLS is a useful alternative to open sternotomy for ventilatory induced hemodynamic compromise post cardiotomy, especially in patients with LVADs.

Cannulation of neonates for venovenous extracorporeal life support

Venovenous access via a double-lumen cannula in the right internal jugular vein is the extracorporeal life support mode of choice for neonates with respiratory failure. We report a simplified method of cannulation. The advantages of this "semi-Seldinger" method include the ability to cannulate without ligating the internal jugular vein, and to adjust the position of the cannula and decannulate without re-exploring the wound.

Use of Two-Dimensional and Contrast Echocardiography for Venous Cannula Placement in Venovenous Extracorporeal Life Support

The objective of this study was to determine the efficacy of two-dimensional and contrast echocardiograms to identify venous cannula position. Sequential sampling of 20 infants was evaluated by contrast echocardiography after meeting institutional criteria for extracorporeal life support. Each infant was placed on venovenous extracorporeal life support using a double-lumen cannula. After surgical placement was thought to be satisfactory, optimal two-dimensional images of the cannula were obtained via a subxiphoid or apical view and 2 ml agitated normal saline were injected rapidly into the nearest infusion port. Patient demographics and mixed venous saturations were noted. Distance of the venovenous cannula to tricuspid valve and distance of the venovenous cannula from the intra-atrial septum was recorded. Echocardiograms were available for review on 18 of the 20 patients. Position of the venovenous cannula in relationship to the tricuspid valve was as follows: < 5 mm (8); 5-10 mm (5); > 10 mm (5). Mixed venous saturations decreased, which indicated less recirculation when the orientation of the tip of the cannula was toward the lateral wall in those who required repositioning. The authors conclude that two-dimensional and contrast echocardiography aid in the positioning of the venovenous cannula. Satisfactory position is approximately 5 mm from the tricuspid valve, with orientation toward the lateral wall of the right atrium.

Use of Two-Dimensional and Contrast Echocardiography for Venous Cannula Placement in Venovenous Extracorporeal Life Support

Use of Two-Dimensional and Contrast Echocardiography for Venous Cannula Placement in Venovenous Extracorporeal Life Support

Jugular ligation does not increase intracranial pressure but does increase bihemispheric cerebral blood flow and metabolism

To answer the following questions: a) Does jugular venous ligation (simulating venovenous extracorporeal life support) alter proximal jugular venous pressure, intracranial pressure, hemispheric cerebral blood flow, or cerebral metabolism? b) Does release of ligation reverse these effects? and c) What are the comparative effects of venous ligation alone vs. venous ligation in combination with arterial ligation? Prospective, randomized, laboratory investigation. Multidisciplinary laboratory setting. Sixteen swine, weighing 8.1 to 12.1 kg, 3 to 4 wks of age. Sixteen swine were randomly assigned to two groups, utilizing a random sequence of vessel ligation. Nine swine underwent occlusion of the right internal and external jugular veins alone (venovenous ligation) followed by release of the occlusion and then occlusion of the right common carotid artery and the right internal and external jugular veins together (venoarterial ligation). The remaining seven swine underwent venoarterial ligation, followed by release of the occlusion and then venovenous ligation. In the experimental group in which venovenous ligation was performed first, the 5, and 30-min release periods after ligation were taken to represent the effects of draining the right jugular vein during venovenous extracorporeal life support. Data were obtained at baseline, 5, and 30 mins after each ligation/release period. Intracranial pressure, right and left internal jugular pressures/flow rates, and cerebral sinus lactate concentrations were measured. Cerebral blood flow was determined using 133Xe clearance methodology, and the cerebral metabolic rate was calculated. There were no significant differences between the ipsilateral internal jugular pressure or extracorporeal life support at 5 or 30 mins after venovenous or venoarterial ligation compared with baseline values or compared with the release of the ligation at 5 or 30 mins. There was a significant increase in right-side (44.7 +/- 2.0 vs. 38.8 +/- 2.4 mL/kg/min; p < .05) and left-side (42.9 +/- 2.3 vs. 38.7 +/- 1.9 mL/kg/min; p < .05) cerebral blood flow 5 mins after venovenous ligation when compared with baseline values. Similarly, after venoarterial ligation, there was a significant increase in right-side (44.6 +/- 2.2 vs. 38.8 +/- 2.4 mL/kg/min; p < .05) and left-side (43.9 +/- 1.5 vs. 38.7 +/- 1.9 mL/kg/min; p < .05) and cerebral blood flow. Cerebral oxygen consumption was significantly increased after venovenous (2.7 +/- 0.2 to 3.2 +/- 0.2 mL/kg/min; p < .05) and venoarterial (2.7 +/- 0.2 to 3.1 +/- 0.2 mL/kg/min; p < .05) ligation at 5 mins after ligation. This increase persisted at the 30-min period and after release of ligation. Ligation of the right jugular veins alone (venovenous ligation) or jugular veins and right carotid artery (venoarterial ligation) does not increase jugular venous pressures or intracranial pressure. However, this procedure does increase cerebral blood flow and cerebral oxygen consumption. These findings demonstrate that there is adequate decompression of the venous system by the cerebrovascular system and retrograde decompression during extracorporeal life support appears unwarranted.

Determination of Native Mixed Venous Saturation During Venovenous Extracorporeal Circulation

The ability to monitor the match between systemic oxygen delivery and consumption using mixed venous oxygen saturation is an important component of management of critically ill patients. Mixed venous oxygen saturation is a particularly useful parameter in circumstances where systemic oxygen delivery is significantly compromised, such as the acute respiratory distress syndrome. With the advent of venovenous extracorporeal life support (ECLS) in the treatment of this condition, however, accurate measurement of true mixed venous oxygen saturation has not been available, because of this artificial elevation of venous oxygen content. Using an algebraic solution, the authors developed an equation to calculate true patient mixed venous oxgen saturation during ECLS. This is accomplished using readily obtainable data such as cardiac output, ECLS flow, ECLS circuit pre and post oxygenator blood oxygen content, pulmonary arterial oxygen saturation, and patient hemoglobin. The formula has been used in an in vitro model, simulating venovenous ECLS and native venous saturation ranging from 20-72%, with a resulting correlation coefficient between calculated and measured saturation of 0.983 and a gamma intercept of 0.7. Using this new mathematical model, previously unobtainable information about the match of oxygen delivery and consumption in venovenous ECLS is now available. This information will facilitate optimal management of oxygen kinetics in patients during venovenous extracorporeal support.

Improvement of Gas Exchange, Pulmonary Function, and Lung Injury With Partial Liquid Ventilation: A Study Model in a Setting of Severe Respiratory Failure

To evaluate gas exchange, pulmonary function, and lung histology during gas ventilation of the perfluorocarbon-filled lung compared with gas ventilation of the gas-filled lung in severe respiratory failure. Application of gas (GV) or partial liquid (PLV) ventilation in lung-injured sheep. A research laboratory at a university medical center. Eleven sheep 17.1 +/- 1.8 kg in weight. Lung injury was induced by intravenous administration of 0.07 mL/kg oleic acid followed by saline pulmonary lavage. When alveolar-arterial oxygen pressure difference (P[A-a]O2) was 600 mm Hg or more and PaO2 was 50 mm Hg or less with fraction of inspired oxygen of 1.0, bijugular venovenous extracorporeal life support (ECLS) was instituted. For the first 30 min on ECLS, all animals were ventilated with gas. Over the ensuing 2.5 h, ventilation with 15 mL/kg gas was continued without intervention in the control group (GV, n = 6) or with the addition of 35 mL/kg of perflubron (PLV, n = 5). At 3 h after initiation of ECLS, Qps/Qt was significantly reduced in the PLV animals when compared with the GV animals (PLV = 41 +/- 13%; GV = 93 +/- 4%; p < 0.005). At the same time point, pulmonary compliance was increased in the PLV when compared with the GV group (PLV = 0.61 +/- 0.14 mL/cm H2O/kg; GV = 0.41 +/- 0.02 mL/cm H2O/kg; p < 0.005). The ECLS flow rate required to maintain the PaO2 in the 50 to 80 mm Hg range was substantially and significantly lower in the PLV group when compared with that of the GV group (PLV = 25 +/- 20 mL/kg/min; GV = 87 +/- 15 mL/kg/min; p < 0.001). Light microscopy performed on lung biopsy specimens demonstrated a marked reduction in lung injury in the liquid ventilated (LV) when compared with the GV animals. In a model of severe respiratory failure, PLV improves pulmonary gas exchange and pulmonary function and is associated with a reduction in pulmonary pathology.

Liquid ventilation improves pulmonary function, gas exchange, and lung injury in a model of respiratory failure.

The authors evaluated gas exchange, pulmonary function, and lung histology during perfluorocarbon liquid ventilation (LV) when compared with gas ventilation (GV) in the setting of severe respiratory failure. The efficacy of LV in the setting of respiratory failure has been evaluated in premature animals with surfactant deficiency. However, very little work has been performed in evaluating the efficacy of LV in older animal models of the adult respiratory distress syndrome (ARDS). A stable model of lung injury was induced in 12 young sheep weighing 16.4 +/- 3.0 kg using right atrial injection of 0.07 mL/kg of oleic acid followed by saline pulmonary lavage and bijugular venovenous extracorporeal life support (ECLS). For the first 30 minutes on ECLS, all animals were ventilated with gas. Animals were then ventilated with either 15 mL/kg gas (GV, n = 6) or perflubron ([PFC], LV, n = 6) over the ensuing 2.5 hours. Subsequently, ECLS was discontinued in five of the GV animals and five of the LV animals, and GV or LV continued for 1 hour or until death. Physiologic shunt (Qps/Qt) was significantly reduced in the LV animals when compared with the GV animals (LV = 31 +/- 10%; GV = 93 +/- 4%; p < 0.001) after 3 hours of ECLS. At the same time point, pulmonary compliance (CT) was significantly increased in the LV group when compared with the GV group (LV = 1.04 +/- 0.19 mL/cm H2O/kg; GV = 0.41 +/- 0.02 mL/cm H2O/kg; p < 0.001). In addition, the ECLS flow rate required to maintain the PaO2 in the 50- to 80-mm Hg range was substantially and significantly lower in the LV group when compared with that of the GV group (LV = 14 +/- 5 mL/kg/min; GV = 87 +/- 15 mL/kg/min; p < 0.001). All of the GV animals died after discontinuation of ECLS, whereas all the LV animals demonstrated effective gas exchange without extracorporeal support for 1 hour (p < 0.01). Lung biopsy light microscopy demonstrated a marked reduction in alveolar hemorrhage, lung fluid accumulation, and inflammatory infiltration in the LV group when compared with the GV animals. In a model of severe respiratory failure, LV improves pulmonary gas exchange and compliance with an associated reduction in alveolar hemorrhage, edema, and inflammatory infiltrate.

Extracorporeal life support for pediatric respiratory failure

The purpose of this report was to examine the Extracorporeal Life Support Organization registry database for predictors of outcome for severe pediatric respiratory failure managed with extracorporeal life support. Retrospective cohort study. Extracorporeal Life Support Organization data registry. All nonneonatal pediatric patients who were treated in the United States with extracorporeal life support for severe pediatric respiratory failure reported to the Extracorporeal Life Support Organization registry as of August 1991. Patients with congenital heart disease and congenital gastrointestinal malformations were excluded from study. Venoarterial or venovenous extracorporeal life support for severe life-threatening pulmonary failures. As of August 1991, 220 pediatric patients meeting study entry criteria were reported to the Registry having received extracorporeal life support for severe pulmonary failure, since 1982. Forty-six percent (102 of 220 patients) were successfully managed with this technology and survived to hospital discharge. The mean patient age was 36.8 +/- 51.6 months. Fifty-one percent of the patients were male. The mean duration of mechanical ventilation before extracorporeal life support was 6.3 +/- 5.9 days. Mean blood gas and ventilatory measurements obtained before extracorporeal life support were as follows: PaCO2 52 +/- 23 torr (6.9 +/- 3.0 kPa); PaO2 59 +/- 32 torr (7.8 +/- 4.3 kPa); estimated alveolar-arterial oxygen gradient 561 +/- 63.4 torr (74.8 +/- 8.5 kPa); peak airway pressure 49.5 +/- 13.1 cm H2O; mean airway pressure 24.3 +/- 8.2 cm H2O; positive end-expiratory pressure 11.8 +/- 6.3 cm H2O; ventilator rate 58 +/- 64.4 breaths/min; and FIO2 0.98 +/- 0.07. The mean duration of extracorporeal life support for all patients was 247 +/- 164 hrs. For the 102 survivors, the mean time for decannulation from extracorporeal life support to extubation from mechanical ventilation was 6.5 +/- 7.6 days. Stepwise multivariate logistic regression modeling found the following variables to be associated with patient survival: a) patient age, b) days of mechanical ventilation before extracorporeal life support, c) peak inspiratory pressure, d) alveolar-arterial oxygen gradient, and e) extracorporeal life support administered since December 31, 1988 (all p < .05). Extracorporeal life support may represent an effective rescue therapy for some selected pediatric patients with severe respiratory failure for whom conventional mechanical ventilation support has failed to improve. Predictors of survival for this life-support therapy exist that may be helpful for individual patient prognostication and future prospective study.

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

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. Retrospective cohort study. Extracorporeal Life Support Organization data registry. 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. Venoarterial or venovenous extracorporeal life support. 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. 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.

Extracorporeal life support for pediatric respiratory failure

The purposes of this report are to a) describe the University of Michigan experience with venoarterial or venovenous extracorporeal life support for severe pediatric pulmonary rescue therapy, and b) examine survivors and nonsurvivors for differences that might be useful for examination in future, prospective studies. Case series report. Phase I study of safety and effectiveness of extracorporeal life support for pediatric respiratory failure. University of Michigan Medical Center. Non-neonatal pediatric patients treated with extracorporeal life support for severe respiratory failure at the University of Michigan. Extracorporeal life support for pulmonary failure. From November 1982 until May 1991, 25 pediatric patients underwent extracorporeal life support for severe pulmonary failure. Twenty patients were treated in the last 36 months. Sixty percent (15/25 patients) survived their life-threatening respiratory illness, were weaned from mechanical ventilation, and were discharged home. The mean patient age was 4.1 yrs, and mechanical ventilation duration before extracorporeal life support was 5.9 days. Mean blood gas data and mechanical ventilation pressures before extracorporeal life support were: peak inspiratory pressure of 48.6 cm H2O, mean airway pressure of 21.9 cm H2O, positive end-expiratory pressure of 9.7 cm H2O, PaCO2 of 43 torr (5.7 kPa), PaO2 of 69 torr (9.1 kPa), estimated alveolar-arterial oxygen gradient of 563 torr (75 kPa), and FIO2 of 0.98. Variables associated with survival included: age of survivors vs. nonsurvivors, 2.1 vs. 7.1 yrs (p less than .02); peak inspiratory pressure of survivors vs. nonsurvivors, 43.1 vs. 57.9 cm H2O (p less than .03); mean airway pressure of survivors vs. nonsurvivors, 18.4 vs. 27.2 cm H2O (p less than .03); and positive end-expiratory pressure of survivors vs. nonsurvivors, 8.1 vs. 12.1 cm H2O (p less than .01). There were no differences detectable in the blood gas values (PaO2, PaCO2, P[A-a]O2) in survivors and nonsurvivors before extracorporeal life support. The number of days mechanical ventilation was used before extracorporeal life support in survivors and in nonsurvivors was similar. Extracorporeal life support is an effective rescue therapy for pediatric patients with severe respiratory failure (University of Michigan survival rate of 60%).

Venovenous extracorporeal life support in neonates using a double lumen catheter.

After satisfactory development and testing of a polyurethane 14 Fr double lumen catheter, we used this device for venovenous extracorporeal life support in neonates who had respiratory failure. This catheter was designed for single site cannulation of the internal jugular vein, thereby sparing the carotid artery from ligation. Cannulation was successful in 17 of 21 neonates, with 15 successful venovenous runs, whereas 2 of the 17 patients were converted to venoarterial bypass because of inadequate support. Oxygenation and CO2 removal were adequate in the remaining patients. Average time on bypass was 111 hours. All 15 patients survived, and exploration of the cannulation site for bleeding was required in three patients. Preoxygenator pressure, recirculation of oxygenated blood, and hemolysis were all within acceptable levels during each run. Venovenous extracorporeal life support with the double lumen catheter can replace venoarterial access in most cases of neonatal respiratory failure.