Comparison of gas and liquid ventilation: clinical, physiological, and histological correlates

Abstract

To differentiate the effects of gas and liquid ventilation on cardiopulmonary function during early development, we compared the clinical, physiological, and histological profiles of gas- and liquid-ventilated preterm lambs (n = 16; 108-116 days gestation). Immediately after cesarean section delivery, ventilation commenced using gas delivered by a volume ventilator (n = 9) or liquid perfluorochemical (n = 7) delivered by a mechanically assisted liquid ventilation system. Pulmonary gas exchange, acid-base status, vital signs, and respiratory compliance were assessed during the 3-h protocol; sections of the lungs were obtained for histological analyses when the animals were killed. Six of nine gas-ventilated lambs expired from respiratory failure before 3 h, with the remaining animals experiencing severe respiratory insufficiency, pneumothoraces, and cardiovascular deterioration. Six of seven liquid-ventilated lambs survived with good gas exchange and cardiovascular stability and without fluorothorax; one experienced ventricular fibrillation before 1 h and expired despite pulmonary stability. Respiratory compliance was significantly greater in the liquid- than in the gas-ventilated lambs. Histological analyses of gas-ventilated lungs demonstrated nonhomogeneous lung expansion, with thick-walled gas exchange spaces containing proteinaceous exudate, hemorrhage, and hyaline membranes. In contrast, liquid-ventilated lungs appeared clear, with thin-walled and uniformly expanded gas exchange spaces that were free of hyaline membranes and luminal debris. Morphometric analyses demonstrated that surface area and gas exchange index were greater in the liquid- than in the gas-ventilated lambs. These results indicate that elimination of surface active forces by liquid ventilation during early development provides more effective gas exchange with less barotrauma compared with gas ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic effects of partial liquid ventilation with perfluorocarbon in acute lung injury

“…A few studies reported hemodynamic compromise during total liquid ventilation. The authors of these studies attributed this result to the filling of the lung with high-density PFCs [2,3]. The observed hemodynamic compromise in these total liquid ventilation studies is speculated to result from pulmonary vascular compression, which is caused by an increase in the alveolar hydrostatic pressure gradient [9], and/or through an impairment of CO via a decrease in right ventricular preload combined with an increase in right ventricular afterload [10].…”

“…Since then PFCs have been investigated extensively as an alternative means of respiratory support, and PFCs oxygenated outside the body have been used in the treatment of acute respiratory failure [2,3]. In 1991 Fuhrman et al [4] demonstrated the feasibility of applying liquid ventilation in healthy animals without the need for a specialized liquid breathing system.…”

Liquid ventilation

“…7 It has also been shown to improve gas exchange and lung function in animal models of respiratory distress. [8][9][10][11] In 1991, Fuhrman et al 12 introduced the technique of using functional residual capacity (FRC) volumes of PFC with conventional gas ventilation -PFC associated gas exchange (PAGE). This technique has become known as partial liquid ventilation (PLV) and it is this technique which has the most promise for practical clinical application.…”

Effects of Perfluorocarbon Associated High Frequency Oscillatory Ventilation on Hemodynamics and Gas Exchange in the Newborn Piglets with Respiratory Distress

“…Several studies suggest newer technologies, such as partial liquid ventilation (PLV) and high-frequency oscillatory ventilation (HFOV) that can reduce the severity of lung injury in experimental and clinical settings (1)(2)(3)(4)(5)(6)(7)(8)(9). HFOV has been known to be effective rescue modality in patients with a significant impairment of gas exchange (10)(11)(12).…”