Nesiritide during extracorporeal membrane oxygenation

Nesiritide is a recombinant formulation of B-type natriuretic peptide (BNP). Preliminary experience in the adult population has shown nesiritide to be an effective agent in the treatment of decompensated congestive heart failure (CHF) in adults. Given its physiological effects, it may be an effective agent in other clinical scenarios. We report the use of nesiritide in two infants during extracorporeal membrane oxygenation (ECMO). In one patient, nesiritide in doses up to 0.09 microg.kg(-1).min(-1) were used to control mean arterial pressure while in the other patient, doses of 0.01-0.03 microg.kg(-1).min(-1) were used to augment urine output. The potential applications of nesiritide and dosing regimens for this agent in the ECMO population are discussed.     

Stunned myocardium during extracorporeal membrane oxygenation

The "stunned myocardium" is a syndrome of reversible myocardial dysfunction that may be mediated by oxygen-derived free radicals. This phenomenon has been seen in some neonates undergoing extracorporeal membrane oxygenation. We performed echocardiograms and measured creatine phosphokinase isoenzymes and lipid peroxide levels in 16 neonates before, during, and after extracorporeal membrane oxygenation. Infants who developed stunned myocardia by echocardiography did so shortly after initiation of bypass and exhibited concurrent elevations of the MB fraction of creatine phosphokinase. Lipid peroxide levels did not simultaneously rise. These data suggest that oxygen-derived free radicals may not cause the stunned myocardium seen in neonates undergoing extracorporeal membrane oxygenation.     

Antithrombin replacement during extracorporeal membrane oxygenation

Heparin remains the predominant anticoagulant during extracorporeal membrane oxygenation (ECMO). Heparin acts by potentiating the anticoagulant effect of antithrombin (ATIII). Acquired ATIII deficiency, common in pediatric patients requiring ECMO, may result in ineffective anticoagulation with heparin. ATIII replacement may result in increased bleeding. Our objective is to determine ATIII's effect on anticoagulation and blood loss during ECMO. A retrospective chart review was performed of all patients at Children's Hospital of Wisconsin who received ATIII while supported on ECMO in 2009. ATIII activity levels, heparin drip rate, and activated clotting times (ACT) were compared before, 4, 8, and 24 h after ATIII administration. Chest tube output and packed red blood cell (pRBC) transfusion volume were compared from 24 h before ATIII administration to 24 h after. Twenty-eight patients received ATIII as a bolus dose during the course of 31 separate times on ECMO support. The median age of these patients was 0.3 years (range 1 day-19.5 years). ATIII activity increased significantly at 8 and 24 h after administration. No significant difference was noted in heparin drip rate, ACT levels, chest tube output, or pRBC transfusion volume. ATIII administration resulted in higher ATIII activity levels for 24 h without a significant effect on heparin dose, ACT, or measures of bleeding.     

Mediastinal hemorrhage during extracorporeal membrane oxygenation

A case of mediastinal hemorrhage along with hemorrhage into a pneumatocele while on extracorporeal membrane oxygenation (ECMO) is presented. Computerized tomography of the chest was utilized to support the diagnosis. Barotrauma to the lungs best explains the inciting event that allowed the hemorrhage to occur once the patient was heparinized for ECMO. This complication serves to point out the importance of commencing early ECMO support before widespread pulmonary and mediastinal barotrauma develops.     

Venovenous extracorporeal membrane oxygenation support for treatment of bilateral spontaneous pneumothorax

Bilateral spontaneous pneumothorax is a rare but serious cause of respiratory distress. We treated a 77-year-old male with severe hypoxia caused by bilateral spontaneous pneumothorax using video-assisted thoracoscopic bullectomy assisted by a venovenous extracorporeal membrane oxygenation (ECMO) device. The patient came to the emergency department of our hospital with complaints of cough and dyspnea, and was hospitalized with right-side spontaneous pneumothorax and left-side pneumonia. After 12 days, a chest radiograph was performed to investigate persistent progressive shortness of breath at rest, which demonstrated contralateral pneumothorax. A chest tube was inserted into the left pleural cavity, and surgery was performed for bilateral pneumothorax by video-assisted thoracoscopic surgery (VATS) assisted by venovenous ECMO. Gas exchange was satisfactory throughout the surgical procedure and the postoperative course was uneventful without complications. Venovenous ECMO was effective for facilitation of VATS and reduced the risk of an intra-operative hypoxic condition.     

Complement activation during prolonged extracorporeal membrane oxygenation

Short-term cardiopulmonary bypass activates the complement system, possibly resulting in pulmonary dysfunction from granulocyte aggregation and pulmonary endothelial damage. These effects may be inhibited by steroids. Prolonged extracorporeal membrane oxygenation (ECMO) is used for newborn respiratory failure, but the effects of ECMO on complement activation are unknown. Twenty-one newborn infants with respiratory failure treated with ECMO were randomly assigned to group I (control, no steroids) or group II (30 mg/kg intravenous methylprednisolone before ECMO). Depletion assays of C3 and C5 were performed in each group at intervals before and during ECMO (declining values indicate complement activation). The groups were compared for complement levels, survival, time on ECMO and on the ventilator, and total hospitalization time. Steroids significantly shortened the time on ECMO and time on the ventilator after ECMO but did not affect survival or total hospitalization time. Steroids also enhanced activation of C3 and C5. Complement activation occurs during ECMO. Steroid administration paradoxically causes earlier complement activation but shortens ECMO and ventilator times. Complement activation during ECMO is of questionable significance. The benefits of steroids during ECMO may be mediated through other mechanisms.     

Venovenous extracorporeal membrane oxygenation during high-risk airway interventions

 Open in a separate windowOBJECTIVESPractice patterns for the use of extracorporeal membrane oxygenation (ECMO) during high-risk airway interventions vary, and data are limited. We aim to characterize our recent experience using ECMO for procedural support during whole-lung lavage (WLL) and high-risk bronchoscopy for central airway obstruction (CAO).METHODSWe performed a retrospective cohort study of adults who received ECMO during WLL and high-risk bronchoscopy from 1 July 2018 to 30 March 2020. Our primary end point was successful completion of the intervention. Secondary end points included ECMO-associated complications and hospital survival.RESULTSEight patients received venovenous ECMO for respiratory support during 9 interventions; 3 WLLs for pulmonary alveolar proteinosis were performed in 2 patients, and 6 patients underwent 6 bronchoscopic interventions for CAO. We initiated ECMO prior to the intervention in 8 cases and during the intervention in 1 case for respiratory decompensation. All 9 interventions were successfully completed. Median ECMO duration was 17.8 h (interquartile range, 15.9–26.6) for the pulmonary alveolar proteinosis group and 1.9 h (interquartile range, 1.4–8.1) for the CAO group. There was 1 cannula-associated deep vein thrombosis; there were no other ECMO complications. Seven patients (87.5%) and 4 (50.0%) patients survived to discharge and 1 year postintervention, respectively.CONCLUSIONSUse of venovenous ECMO to facilitate high-risk airway interventions is safe and feasible. Planned preprocedural ECMO initiation may prevent avoidable respiratory emergencies and extend therapeutic airway interventions to patients otherwise considered too high-risk to treat. Guidelines are needed to inform the utilization of ECMO during high-risk bronchoscopy and other airway interventions.     

Major surgical intervention during extracorporeal membrane oxygenation.

Of 135 patients treated with extracorporeal membrane oxygenation (ECMO) between January 1987 and December 1989, 19 (14.0%) patients underwent surgical procedures while on ECMO. Thirteen (68%) patients had operations related to hemorrhage, including cannula site (6), mediastinal (1), hemoperitoneum (3), and hemothorax (3). Six of 13 patients required repetitive operations for bleeding; 4 of 6 died. Six (35%) patients had operations for congenital pathology including patent ductus (PDA) ligation (2), repair of transposition of the great vessels (2), repair of coarctation (1), and repair of congenital diaphragmatic hernia (3). One patient had multiple simultaneous procedures performed. Of these 6 patients, 4 were decannulated immediately and 2 were decannulated within 28 hours following surgery without any bleeding complications. Fifteen of 19 patients were operated on in the neonatal intensive care unit. The 4 remaining patients required transport on ECMO to the surgical suite. Thirteen of the 19 patients requiring surgical intervention on ECMO survived. In the 13 survivors, the mean time to decannulation postoperative was 45 hours, and in those that died it was 90 hours. Our experience suggests that surgical intervention while on ECMO is technically feasible with the best results achieved when rapid discontinuation of ECMO can be accomplished postoperatively. Due to this fact major surgical intervention should be postponed if possible until near the conclusion of the ECMO therapy.     

Severe myocardial dysfunction during extracorporeal membrane oxygenation.

Of the 102 neonates with respiratory failure supported with extracorporeal membrane oxygenation (ECMO) at this institution between 1984 and 1987, 8 patients developed severe myocardial dysfunction that was noted shortly after onset of bypass. The neonates in the cardiac dysfunction group were more hypoxic (average PaO2 = 26 +/- 8 mm Hg v 41 +/- 19 mm Hg, P less than .01) in the immediate pre-ECMO period. Seventy-five percent were unstable hemodynamically (6 hypotensive, 3 bradycardic, 2 sustained cardiac arrest, 4 required epinephrine pressor support). On ECMO, 5 of the 8 neonates developed an ischemic cardiomyopathy that lasted for less than 24 hours and resolved without therapeutic intervention. In the other 3 cases, prolonged periods of dysfunction were noted and afterload reduction through administration of tolazoline or hydralazine was beneficial. These 8 patients serve to demonstrate the reversible nature of postischemic cardiac dysfunction in patients on ECMO and in the neonatal population in general.     

Pulmonary embolism and myocardial hypoxia during extracorporeal membrane oxygenation

The treatment of a newborn with severe meconium aspiration by venoarterial extracorporeal membrane oxygenation (ECMO) was complicated by myocardial hypoxia with a marked decrease of myocardial contractility. The onset of the cardiac hypoxia was related to a pulmonary artery embolus. The origin of the embolus was a deep femoral vein thrombosis, caused by a central vein catheter, which was inserted 1 day before ECMO by venous cutdown. The possible pathophysiology of myocardial hypoxia in this patient is discussed, especially with regard to myocardial perfusion, supporting the hypothesis of coronary perfusion occuring with blood from the left ventricle and not from the arterial cannula in the aorta.     

Life-threatening intrathoracic complications during treatment with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) has been successful (greater than 80% survival) in 35 centers in greater than 900 newborns with severe respiratory failure having an estimated mortality of greater than 80% on conventional management. During the last 3 years we have treated 79 newborns with 74 survivors (94%). Their diagnoses included meconium aspiration, persistent fetal circulation, respiratory distress syndrome, congenital diaphragmatic hernia, and sepsis. Seven patients (9%) had life-threatening intrathoracic complications requiring emergent intervention while on ECMO: tension hemothorax (3), tension pneumothorax (2), and pericardial tamponade (2). Pericardial tamponade and tension hemothorax and pneumothorax show a similar pathophysiology of increasing intrapericardial pressure and decreasing venous return. Perfusion is initially maintained by the nonpulsatile flow of the ECMO circuit before further decrease in venous return results in decreasing ECMO flow and progressive hemodynamic deterioration. Each of the seven patients demonstrated a clinical triad that includes increasing PaO2 and decreasing peripheral perfusion (as evidenced by decreasing pulse pressure and decreasing SvO2) followed by decreasing ECMO flow with progressive deterioration. The diagnoses were confirmed by transillumination, chest x-ray, or cardiac echocardiogram. Initial emergent placement of a percutaneous drainage catheter was temporizing in all seven cases. However, four patients required emergent thoracotomy for definitive treatment while still on ECMO. All seven patients were weaned from ECMO and are short-term survivors (6 months to 3.5 years). As use of ECMO for newborn severe respiratory failure increases, responsible physicians must be familiar with life-threatening intrathoracic complications and appropriate treatment strategies.     

The significance of ductal shunting during extracorporeal membrane oxygenation

The purpose of this study was to evaluate the significance and direction of shunts at the level of the foramen ovale or ductus arteriosus in full-term newborns with neonatal respiratory failure who were placed on extracorporeal membrane oxygenation (ECMO). A decrease in left ventricular dimension was expected when infants were placed on ECMO but did not occur. A left-to-right shunt was demonstrated at the ductal level in nine of 12 infants early in the course of ECMO before pulmonary resistance decreased. Presumably, the lack of change in the left ventricular dimension when infants were placed on bypass was due to a left-to-right shunt at the ductal level with ductal flow replacing the right heart output, being drawn into the bypass circuit.     

Argatroban in extracorporeal membrane oxygenation

The objective of this study was to assess the required dose and anticoagulatory effect of argatroban (Mitsubishi, Pharma Deutschland GmbH, Düsseldorf, Germany), a direct thrombin inhibitor approved for anticoagulation in patients with heparin-induced thrombocytopenia (HIT) undergoing extracorporeal membrane oxygenation (ECMO). Nine consecutive patients undergoing ECMO for severe acute respiratory distress syndrome (ARDS) and presenting with suspected HIT were treated with a continuous argatroban infusion. Coagulation variables were measured and dose adjustments of argatroban were performed to target for an activated partial thromboplastin time (aPTT) of 50 to 60 s. The first patient received argatroban 2 microg/kg/min as recommended by the manufacturer. This resulted in excessive anticoagulation and severe bleeding. The consecutive eight patients received a 10-fold lower dose (0.2 microg/kg/min). This dose sufficiently increased aPTT time from 46 +/- 6 s to 65 +/- 14 s (P < 0.001) and thrombin time from 18 +/- 8 s to 45 +/- 11 s (P = 0.001). The maintenance dose averaged 0.15 microg/kg/min. Duration of argatroban infusion for ECMO averaged 4 +/- 1 days and no oxygenator or extracorporeal system clotting was observed. In three of nine patients (33%), HIT was confirmed. Argatroban is a feasible and effective anticoagulant for patients with suspected HIT undergoing ECMO. However, a dose 10-fold lower than that recommended by the manufacturer is sufficient to achieve appropriate anticoagulation in critically ill patients undergoing ECMO.     

The effect of left-to-right shunting on coronary oxygenation during extracorporeal membrane oxygenation.

BACKGROUND/PURPOSE: Blood perfusion to the coronary artery (CA) during venoarterial (VA) extracorporeal membrane oxygenation (ECMO) was examined to determine whether it was receiving highly oxygenated ECMO blood or desaturated blood from the pulmonary circulation of diseased lungs. METHODS: In the first experiment, left ventricle output and oxygen saturation in the left ventricle (LV) and CA were measured in dogs placed on VA ECMO. In the second experiment, dogs with an artificial subclavian-pulmonary artery shunt were placed on VA ECMO at 100 mL/kg/min, and oxygen saturation was measured as the shunt flow increased. RESULTS: Without an artificial shunt, a substantial portion of coronary perfusion was found to be supplied by the left ventricle (54 + 30%), even at a high ECMO flow rate of 100 mL/kg/min and low LV output (22+/-17%) relative to ECMO flow. With a shunt, oxygen saturation in the CA was more than 95%, even when shunt flow was only 7.5% of ECMO flow and output from the left ventricle was less than 25% of the ECMO flow rate. CONCLUSIONS: These results suggest that an excessive "lung rest" strategy during VA ECMO may produce suboptimal coronary oxygenation possibly leading to myocardial damage. The presence of a small left-to-right shunt may prevent coronary hypoxia.     

Left ventricle unloading by percutaneous pigtail during extracorporeal membrane oxygenation

Arterial-venous extracorporeal membrane oxygenation (ECMO) is more and more used as first line mechanical support in acute cardiopulmonary failure. Important pitfall of this technique is the inappropriate unloading of left ventricle (LV) in case of myocardial insufficiency, leading to pulmonary stasis and inadequate myocardial recovery. We report our experience of left side unloading by a 7-F pigtail, introduced in the LV through the aortic valve, connected to the venous drainage. Echographic guidance is sufficient to pigtail positioning and follow-up monitoring avoiding catheterization laboratory transport. With this approach we were able to support three different patients, resolving LV distension and preventing lung congestion, without major complication.