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.
Five cases of unilateral vocal cord paralysis/paresis were diagnosed following extracorporeal membrane oxygenation for newborn respiratory failure. All were right sided and transient in nature. None of the five patients had other findings commonly associated with vocal cord palsy. The extracorporeal membrane oxygenation procedure requires surgical dissection in the carotid sheath on the right side of the neck, an area immediately adjacent to both the vagus and recurrent laryngeal nerve. It is speculated that vocal cord paralysis in these infants was acquired as a result of the extracorporeal membrane oxygenation cannulation. Although the vocal cord paralysis resolved in all cases, two patients had difficult courses after extracorporeal membrane oxygenation. Therefore, laryngoscopic examination should be considered for patients after extracorporeal membrane oxygenation.
Nine medical centers collaborated in a prospective randomized study to evaluate prolonged extracorporeal membrane oxygenation (ECMO) as a therapy for severe acute respiratory failure (ARF). Ninety adult patients were selected by common criteria of arterial hypoxemia and treated with either conventional mechanical ventilation (48 patients) or mechanical ventilation supplemented with partial venoarterial bypass (42 patients). Four patients in each group survived. The majority of patients suffered acute bacterial or viral pneumonia (57%). All nine patients with pulmonary embolism and six patients with posttraumatic acute respiratory failure died. The majority of patients died of progressive reduction of transpulmonary gas exchange and decreased compliance due to diffuse pulmonary inflammation, necrosis, and fibrosis. We conclude that ECMO can support respiratory gas exchange but did not increase the probability of long-term survival in patients with severe ARF. (JAMA242:2193-2196, 1979)
This report describes the development of an implantable gas exchange device. The device is composed of hollow fiber elements wound around a central open core enclosed in a compliant outer casing, offering very low resistance to blood while providing adequate gas exchange. The purpose of this study was to determine if this device design can completely support the gas exchange requirements of a large animal when the device is placed in series with the main pulmonary artery (PA). Six 40-80 kg adult sheep were used. The device was placed with vascular grafts anastomosed end to side on the proximal and distal main PA. The study began with the entire right ventricular blood flow being diverted through the device by occlusion of a snare around the PA between the vascular grafts. Total gas exchange then was provided by the device and the endotracheal tube was clamped. Results showed that this pumpless potentially implantable device is capable of completely supporting the gas exchange requirements of the experimental animals for up to 8 hours in the acute setting without significant change in cardiac index (CI) and oxygen consumption (VO2) compared with baseline. CI = 55.0 +/- 17.0 cc/min/kg versus 45.0 +/- 17.3 cc/min/kg. VO2 = 1.90 +/- 0.96 cc O2/min/kg versus 2.08 +/- 0.54 cc O2/min/kg.
Traditionally, adult sepsis has been considered a contraindication to extracorporeal life support (ECLS). The objective of this study was to review the authors' institutional experience with a subgroup of adult patients requiring ECLS for severe respiratory failure and sepsis. Hospital records from 100 consecutive adult patients with respiratory failure placed on ECLS between 1990 and 19% were retrospectively reviewed. Patients with sepsis as a primary indication were identified, and blood culture data reviewed. Data were analyzed with t tests and chi-square and are presented as mean $pM standard deviation. Multiple logistic regression determined the impact of sepsis and positive blood cultures (PBCs) on survival. Fourteen patients required ECLS for sepsis; 36 had PBCs during hospitalization (15 before or during ECLS). Septic patients had lower pre-ECLS PaO2/FiO2 ratios (septic: 53 $pM 14 mmHg, non-septic: 70 $pM 68 mmHg, p = 0.04). Patients with PBCs before or during ECLS were younger (PBC: 29 $pM 6 years, no PBC: 35 $pM 13 years, p = 0.003), remained on ECLS longer (PBC: 485 $pM 336 hours, no PBC: 232 $pM 212 hours, p = 0.01), and were more frequently cannulated within 12 hours (PBC: 15/ 15, no PBC 60/85 p = 0.02). Neither group differed in organ dysfunction (incidence or type), frequency of respiratory recovery, or survival. Neither sepsis nor positive blood cultures were independently predictive of mortality. Sepsis and positive blood cultures do not adversely affect outcome in adult patients with respiratory failure requiring ECLS. ASAIO Journal 1998;44:263–266.
HEISS, KURT M.D.; MANNING, PETER M.D.; OLDHAM, KEITH T. M.D.; CORAN, ARNOLD G. M.D.; POLLEY, THEODORE Z. JR. M.D.; WESLEY, JOHN R. M.D.; BARTLETT, ROBERT H. M.D. Author Information
An automatic controller for extracorporeal life support (ECLS) was designed and tested in vivo. The design goal was to improve upon manually-operated ECLS by automatically adjusting system parameters to meet oxygen (O/sub 2/) delivery and carbon dioxide (CO/sub 2/) removal needs of the patient, while monitoring system performance to enhance safety. The patient/ECLS System was modeled by two first order systems with a time delay representing transit times for blood moving between the patient and blood gas sensors. One proportional-plus-integral controller adjusted blood flow based on venous O/sub 2/ content, and another varied gas flow through the gas exchanger based on venous PCO/sub 2/ measurements. Tuning of controllers was based on open loop step response. The controller was successfully implemented and validated in a sheep model. This controller would minimize the duration of support (thereby reducing cost and invasiveness of the procedure), as the patient would be weaned from support as cardiopulmonary function improved.
