The Edmonton experience with venovenous extracorporeal membrane oxygenation

Developing a new pediatric extracorporeal membrane oxygenation (ECMO) program

OBJECTIVES

We aimed to critically evaluate the effectiveness of a designated ECMO team in our ECMO selection process and patient outcomes in the first 3 years of our low-volume pediatric ECMO program.

METHODS

We conducted a retrospective chart review of patients who received an ECMO consultation between the start of our program in March 2015 and May 2018. We gathered clinical and demographic information on patients who did and did not receive ECMO, and described our selection process. We reflected on the processes used to initiate our program and our outcomes in the first 3 years.

RESULTS

69 patients received consultations, and of those, 50 patients were potential candidates. 19 (38%) of the candidates were ultimately placed on ECMO. There were statistically significant differences in oxygen saturation, paO₂, oxygenation index, A-aDO₂, lactate, and pH between the patients who went on ECMO and who did not. We improved our outcomes from 0% survival to discharge in 2015, to 60% in 2018, with an average of 63% survival to discharge over the first 3 years of our program.

CONCLUSIONS

In a low-volume pediatric ECMO center, having a designated team to assist in the patient selection process and management can help provide safe and efficient care to these patients, and improve patient outcomes. Having a strict management protocol and simulation sessions involving all members of the medical team yields comfort for the providers and optimal care for patients. This study describes our novel structure, processes, and outcomes, which we hope will be helpful to others seeking to develop a new pediatric ECMO program.

Venovenous extracorporeal membrane oxygenation in neonatal respiratory failure: does routine, cephalad jugular drainage improve outcome?

BACKGROUND/PURPOSE

Extracorporeal membrane oxygenation (ECMO), may be life saving for infants with severe respiratory failure, and when possible, veno-venous bypass through a jugular double lumen cannula, can be expected to provide satisfactory support for most patients. Some ECMO centers favor routine placement of a cephalad jugular cannula for the theoretical benefits of augmented (desaturated) venous return, reduction of atrial recirculation, and cerebral venous decompression. The purpose of this study was to querie the ELSO registry for patients who had undergone VV-ECMO and compare outcomes for patients with a double lumen cannula only (VVDL), with those who had both a double lumen and cephalad jugular cannula (VVDL + V).

METHODS

With institutional review board (IRB) approval, the Extracorporeal Life Support Organization (ELSO) registry (Ann Arbor, MI) was queried from January 1, 1989 to December 31, 2001, and all "neonatal respiratory" patients undergoing VV-ECMO via either the VVDL or VVDL + V modes were identified. Group comparisons by age, diagnosis, hours on bypass, mean flow rates (Q) at 4 and 24 hours, mean airway pressures (MAP) at initiation and at 24 hours of bypass, complications (including neurologic and cannula-specific), need for conversion to veno-arterial (VA) ECMO, and survival were performed. A similar analysis was performed on a congenital diaphragmatic hernia (CDH) patient subgroup. Student's t tests were used to compare means between groups, with P values of less than.05 considered significant.

RESULTS

The querie generated a total of 2,471 patients: 2,379 (96.3%) VVDL, and 92 (3.7%) VVDL + V. The groups were comparable with the only significant differences being a higher mean airway pressure at 24 hours of bypass and a more frequent use of inotropes during extracorporeal life support (ECLS) in the VVDL + V group. Comparison of a CDH patient subset (280 from the VVDL group and 25 from the VVDL + V group) showed the following significant differences: more frequent use of inotropes, higher MAP at 24 hours, and higher mean flow rates at 4 and 24 hours, all in the VVDL + V group. Patient outcomes, including survival, complications, and rates of conversion to VA bypass were comparable between like groups.

CONCLUSIONS

The theoretical benefits of routine placement of a cephalad jugular cannula during VV-ECMO via a jugular double lumen cannula are not substantiated by critical analysis of ELSO data.

Quantification of recirculation by thermodilution during venovenous extracorporeal membrane oxygenation

PURPOSE

The aim of this study was to determine whether recirculation could be quantified by a thermodilution technique during venovenous (VV) extracorporeal membrane oxygenation (ECMO) in a rabbit model.

METHODS

Five New Zealand white rabbits, mean weight, 4.5 (range, 3.7 to 5.7) kg, were anesthetized, instrumented, cannulated with a double-lumen catheter, and placed on VV ECMO. Serial injections of ice-cold saline were performed at the arterial arm of the circuit, and the resultant temperature change at various pump flows was measured at the venous arm of the circuit using a thermistor-tipped catheter and a cardiac output computer. Results were compared with the respective 100% recirculation measured with all the circuit flow passing through the bridge.

RESULTS

Using linear regression, recirculation percentage could be calculated as: 19 + 0.1 x pump flow (R2 = 0.81, P < .005). Recirculation correlated positively with pump flow. Variability between results at each flow was less than 10%.

CONCLUSIONS

Recirculation can be quantified during VV ECMO by measuring the change in temperature in the venous arm using a cardiac output computer after injection of a known quantity of ice-cold saline in the arterial side of the circuit. The effect of interventions to reduce recirculation can be assessed conveniently and reliably.

Two years' follow-up of newborn infants after extracorporeal membrane oxygenation (ECMO)

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) is a technique of extracorporeal oxygenation used in newborn infants with refractory hypoxemia after failure of maximal conventional medical management, when mortality risk is higher than 80%. We retrospectively reviewed all the neonates treated by ECMO between October 1991 and September 1997 in our newborn intensive care unit.

METHODS

Fifty-seven patients were treated with ECMO for severe respiratory failure: congenital diaphragmatic hernia (CDH) (n=23), neonatal sepsis (NS) (n=14), meconium aspiration syndrome (MAS) (n=12), and others (n=8). Mean gestational age and birth weight were 38+/-2 weeks and 3200+/-500 g, respectively. Oxygenation index was 61+/-8. Both venovenous (n=28) or venoarterial ECMO (n=29) were used. The mean time at ECMO initiation was 47 h (range 8 h-2 months). The mean duration was 134+/-68 h. In each case of VA ECMO, carotid reconstruction was performed. Survival at 2 years was 40/57 (70%) (CDH 12/23 (52%), NS 11/14 (79%), MAS 12/12 (100%), others 5/8). Follow-up at 2 years was available in 36 survivors.

RESULTS

Neurodevelopmental outcome was not related to the initial diagnosis: normal neurologic development (n=30), cerebral palsy (n=5), and neurologic developmental delay (n=1). Two patients remained oxygen dependant at 2 years, and four required surgical treatment for severe gastroesophageal reflux. Respiratory and digestive sequelae were more frequent in the CDH group (P<0.01). Patency and flow of the repaired carotid artery was assessed in 20 infants at 1 year of age using Doppler ultrasonography: normal (n=10), <50% stenosis (n=9), and >50% stenosis (n=1).

CONCLUSION

ECMO increased survival of newborn infants with refractory hypoxemia. However, higher a survival rate and lower morbidity were found in non-CDH infants than in congenital diaphragmatic hernia.

Pathogenesis and management of respiratory insufficiency following pulmonary resection

The underlying principle of the surgical treatment of non-small-cell lung cancer (NSCLC) is complete removal of the local/regional disease within the thorax. Pulmonary resection should be as conservative as possible without compromising the adequacy of tumor removal. A multitude of factors influence the incidence and severity of complications following pulmonary resection including the pre-operative physical and psychological status of the patient, the pathologic process requiring resection, the physiologic impact of the procedure, and the addition of pre-operative or postoperative adjuvant therapy. The insidious onset of interstitial changes on chest X-ray (CXR) 1 to 2 days after pulmonary resection forewarns of respiratory distress; however, the pathophysiology of adult respiratory distress syndrome (ARDS) with progression to respiratory failure requiring mechanical ventilation and advanced critical care often unfolds. Management of patients with severe respiratory failure remains primarily supportive. "Good critical care" is the mainstay of therapy: this includes gentle mechanical ventilation to avoid ventilator-induced barotrauma and over-extension of remaining functional alveoli, diuresis, infection identification and management, and nutritional support. New therapeutic strategies that may impact on outcomes in the adult population include pressure-limited ventilation (permissive hypercapnia), inverse ratio ventilation, high-frequency jet ventilation, high-frequency oscillatory ventilation, intratracheal pulmonary ventilation, and prone position ventilation. In addition, alternative therapies such as partial liquid ventilation, inhaled nitric oxide, and extracorporeal techniques including extracorporeal membrane oxygenation (ECMO), extracorporeal carbon dioxide removal (ECCO(2)R), intravascular oxygenation (IVOX), and arteriovenous carbon dioxide removal (AVCO(2)R), provide additional modalities. A component of some or all of these strategies is finding a role in clinical practice.