Partial liquid ventilation versus conventional mechanical ventilation with high PEEP and moderate tidal volume in acute respiratory failure in piglets

A randomized trial of delayed extubation for the reduction of reintubation in extremely preterm infants

OBJECTIVE

To compare immediate extubation versus delayed extubation after 36 hr in extremely low-birth weight infants receiving gentle mechanical ventilation and perinatal lung protective interventions. Our hypothesis was that a delayed extubation in this setting would decrease the rate of reintubation. STUDY DESIGN/METHODOLOGY: A prospective, unmasked, randomized, controlled trial to compare immediate extubation and delayed extubation after 36 hr. Optimized ventilation in both groups included continuous tracheal gas insufflation (CTGI), prophylactic surfactant administration, low oxygen saturation target and moderate permissive hypercapnia. Successful extubation for at least 7 days was the primary criterion and ventilatory support requirements until 36 weeks gestational age the main secondary criteria.

PATIENT SELECTION

Eighty-six infants under 28 weeks gestational age in a single neonatal intensive tertiary care unit.

RESULTS

Delayed extubation (1.9 +/- 0.8 days vs. 0.5 +/- 0.7 days) did not improve the rate of successful extubation but had no long-term adverse effects. CTGI and the lung protective strategy we describe resulted in a very gentle ventilation. The rate of survival without bronchopulmonary dysplasia (BPD, defined as any respiratory support at 36 weeks gestational age) was similar in the two groups and remarkably high for the global population (78%) and for the subgroup of infants <1,000 g at birth (75%).

CONCLUSIONS

Adding 36 hr of optimized mechanical ventilation before first extubation does not improve the rate of successful extubation but has no adverse effects.

Partial liquid ventilation with low-dose perfluorochemical and high-frequency oscillation improves oxygenation and lung compliance in a rabbit model of surfactant depletion

BACKGROUND

Partial liquid ventilation (PLV) with perfluorochemical (PFC) has been advocated as a new therapy for acute respiratory distress syndrome in both clinical and animal studies, meconium aspiration syndrome, and RDS. PFC is referred to as liquid PEEP because it gets distributed to the most gravity-dependent regions of the lung due to its density. High-frequency oscillation (HFO) has been shown to prevent both acute and chronic lung injury in the management of very low birth weight infants with RDS, with gentle ventilation approach. Specifically, HFO with aggressive and adequate lung volume recruitment has been shown to reduce the incidence of chronic lung disease in very low birth weight infants. We hypothesized that PLV along with HFO might be effective in ARDS in an adult rabbit model.

OBJECTIVES

To examine the efficiency of low-dose PLV with with HFO on pulmonary gas exchange and lung compliance in a surfactant-depleted rabbit model.

METHODS

After induction of severe lung injury by repeated saline lung lavage, 19 adult white Japanese rabbits were randomized into two groups that received PLV with HFO (n=9) or HFO gas ventilation (n=10). Physiological and blood gas data were compared between the two groups by analysis of variance.

RESULTS

The HFO-PLV group showed improved total lung compliance with maintenance of significantly lower mean airway pressure as compared with the HFO-GAS group so as to keep SpO2>90%.

CONCLUSIONS

The addition of a low dose of PFC with HFO was effective in achieving adequate oxygenation, with a reduction in further lung injury in neonates.

Partial liquid ventilation combined with two different gas ventilatory strategies in acute lung injury in piglets: Effects on gas exchange, respiratory mechanics, and hemodynamics

BACKGROUND/PURPOSE

Partial liquid ventilation (PLV) has been shown to improve oxygenation and lung mechanics in different models of acute lung injury. This study was designed to investigate the effects of 2 gas ventilatory strategies during PLV on gas exchange, respiratory mechanics, and hemodynamics in acute lung injury in piglets.

METHODS

After induction of acute lung injury, the animals were assigned randomly to 2 groups with different positive end-expiratory pressure (PEEP) levels and tidal volumes (Vt) (group A, Vt > 12.5 mL/kg; PEEP = 6 cm H2O, n = 7; group B, Vt < 9 mL/kg, PEEP = 12 cm H2O, n = 7). Thereafter, the perfluorocarbon (PFC) liquid (30 mL/kg) was instilled into the endotracheal tube. Cardiorespiratory parameters were measured at baseline, after induction of acute lung injury, and every 30 minutes up to 120 minutes.

RESULTS

During PLV, oxygenation significantly improved with no difference between both gas ventilatory strategies. The high PEEP-moderate Vt gas ventilatory strategy reduced the inspiratory airway resistance and was associated with moderate hypercapnia. There were no significant differences in hemodynamics and respiratory compliance between both gas ventilatory strategies.

CONCLUSIONS

The results of this pilot study suggest that oxygenation was equally improved during PLV. This effect was independent of the mode of gas ventilation. However, the high PEEP-moderate Vt gas ventilatory technique resulted in moderate hypercapnia.