Introductioa: PLV improves oxygénation and lung compliance in various ninui models of lung injury; however, little is known about its effects on organ blood flow. It has been hypothesized that because of perflubron's density the perflubron filled lung may impair venous return thereby raising intracerebral vascular resistance resulting in lower CBF. Using radiolabdled microspberes we measured CBF at varying mean airway pressures (Paw) under normocapnea and permissive hypercapnea. Methods: Piglets (4-9 kg) underwent mechanical ventilation and placement of monitoring lines for arterial, pulmonary artery, sagin sinus and intracranial pressures. Lung injury was induced by successive lavage of 35 mL/kg of saline at escalating levels of PEEP to a PaOj of less than 120 torr. After ventilation for one hour at a tidal volume of 14 mL/kg and FHDj of 1, animals were randomized to receive either conventional mechanical ventilation (CMV) or PLV. Spheres were injected at baseline (before loading with perflubron 30 mL/kg (UtpuVent9, Alliance Pharmaceutical Corp., San Diego, CA and Hoescht Marion Roussel, Bridgewater, NJ)), and then at each of four combinationof high (T) Paw (18-20 cmlfeO) or low (i) Paw (12-14 cmHiOX and iPaCOj (35-45 ton) or IPaCOj (55-65 ton). CBF was analyzed by ANOVA. After correction of CBF to a PaCO] of 40 torr assuming a 3% A /torr (CBF40), combined CBF40 at Iand 4 Paw were compared by T-test Results: CBF and CBF40 is expressed as % of baseline [mean ±SD (N)J. CBF t Paw/I PaCO T Paw /I PaÇQ, i Paw At PaCO, 4-Paw 4 PaCO, CMV I ±133 (7) 50 ±9(6) 168 ±66 (5) 93 ±65 (7) PLV 195 ±71 (6) 92 ±44 (7) 156 ±161 (6) 104 ±31 (6) CBF40 Ail T Paw Alii Paw CMV 53 ±28(13) 97 ±50 (12) y<0.05 vs. PLV PLV 80 ±49 (13) 93 ±64 (12) Conclusion: CBF did not differ between modes of ventilation, When CBF was corrected for PaCO;, PLV was associated with higher CBF40 at t Paw than CMV.
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine