Extracorporeal Lung Assist with Heparin-Coated Systems

Extracorporeal lung assist (ELA) has been recommended for the treatment of ARDS if conventional therapy fails. However, the need for nearly complete anticoagulation is a major risk factor for hemorrhagic complications. We describe our experience with 13 ARDS patients treated with ELA using heparin-coated systems (Carmeda). Maintaining partial thromboplastin time and activated clotting time within or close to the normal range, even major surgery (20 thoracotomies and 2 laparotomies) could be performed without undue bleeding complications related to anticoagulation during extracorporeal support. Eight of the 13 patients survived. The use of heparin-coated systems allows prolonged ELA with nearly physiological coagulation function, permitting major surgical intervention. It enhances the safety margin of extracorporeal gas exchange and may ultimately extend its indications.

Positive end-expiratory pressure reduces renal excretion without hormonal activation after volume expansion in dogs

Controlled mechanical ventilation (CMV) with positive end-expiratory airway pressure decreases urine output and renal sodium excretion. This study investigates--independent of surgical stress, general anesthesia, and sedation--the influences of antidiuretic hormone, atrial natriuretic peptide, plasma renin activity, and aldosterone on decreased urine output and renal sodium excretion during CMV with positive end-expiratory airway pressure. Hemodynamic, renal, and hormonal parameters were measured over a 4-h period in six trained, nonanesthetized, chronically tracheotomized dogs under two conditions: 1) control: hours 1-4, spontaneous breathing at continuous positive airway pressure of 4 cmH2O; and 2) CMV 20: hour 1, continuous positive airway pressure of 4 cmH2O; hours 2 and 3, CMV with a mean airway pressure of 20 cmH2O; and hour 4, continuous positive airway pressure of 4 cmH2O. Throughout the experiments, 0.5 ml.kg body weight-1.min-1 balanced electrolyte solution was administered intravenously. During the 2nd and 3rd h of CMV 20, urine volume decreased by 43% and sodium excretion decreased by 44% when compared with control values (P less than 0.05). The glomerular filtration rate decreased from 4.4 +/- 0.1 to 3.9 +/- 0.1 ml.kg-1.min-1 (P less than 0.05) during the 2nd h and from 4.4 +/- 0.1 to 4.1 +/- 0.1 ml.kg-1.min-1 (P less than 0.05) during the 3rd h of CMV 20. Fractional sodium excretion decreased from 4.7 +/- 0.3% to 2.9 +/- 0.2% (P less than 0.05) during the 2nd h and from 7.5 +/- 0.3% to 4.6 +/- 0.2% (P less than 0.05) during the 3rd h of CMV 20, compared with values during the control period.(ABSTRACT TRUNCATED AT 250 WORDS)

Major thoracic surgery during long-term extracorporeal lung assist for treatment of severe adult respiratory distress syndrome (ARDS)

Surgery in patients treated with extracorporeal lung assist (ELA) carries a high risk of life threatening bleeding complications caused by the need for systemic anticoagulation. A case report describing a successful surgical intervention for the repair of a broncho-pleural leakage by thoracotomy during ELA is presented. A newly developed heparin coated extracorporeal system was used in a patient being treated for severe adult respiratory distress syndrome (ARDS) after left sided pneumectomy. The heparin coated system allowed discontinuation of systemic heparinization intraoperatively without coagulation complications related to the extracorporeal system. This procedure was followed by resolution of the ARDS.

Extracorporeal lung assist with heparin-coated systems

Extracorporeal lung assist (ELA) has been recommended for the treatment of ARDS if conventional therapy fails. However, the need for nearly complete anticoagulation is a major risk factor for hemorrhagic complications. We describe our experience with 13 ARDS patients treated with ELA using heparin-coated systems (Carmeda). Maintaining partial thromboplastin time and activated clotting time within or close to the normal range, even major surgery (20 thoracotomies and 2 laparotomies) could be performed without undue bleeding complications related to anticoagulation during extracorporeal support. Eight of the 13 patients survived. The use of heparin-coated systems allows prolonged ELA with nearly physiological coagulation function, permitting major surgical intervention. It enhances the safety margin of extracorporeal gas exchange and may ultimately extend its indications.