Effect of Positive End-Expiratory Pressure After Porcine Unilateral Left Lung Transplant

Abstract

Objectives: To evaluate the effects of 2 different levels of positive end-expiratory pressure on pigs who had unilateral lung transplants. Materials and Methods: A left lung transplant was performed in 12 pigs. The animals were randomized into 2 groups based on positive end-expiratory pressure: group 1 (5 cm H 2 O) and group 2 (10 cm H 2 O). Hemodynamics, gas exchange, and respiratory mechanics were measured before and after surgery. Cytokines, oxidative stress, and histologic scores were assessed in the lung tissue of each pig. Results: Pigs in group 2 exhibited a significantly higher mean heart rate (P = .006), static compliance (P = .001), lower mean arterial pressure (P = .003), and airway resistance (P = .001) than did pigs in group 1. There were no postoperative differences between the groups in concentrations of thiobarbituric acid reactive substances, superoxide dismutase, and interleukin 8. At the end of the observation period, pigs in group 2 had higher levels of thiobarbituric acid reactive substances (P = .001) and interleukin 8 (P = .05), and pigs in group 1 had higher levels of superoxide dismutase (P = .05) than they did at baseline. Conclusions: After unilateral lung transplant, higher positive end-expiratory pressure was associated with improved respiratory mechanics, a negative effect on hemodynamics, a stronger inflammatory response, and increased production of reactive oxygen species, but no effect on gas exchange.

Effects of peep on lung injury, pulmonary function, systemic circulation and mortality in animals with uninjured lungs—a systematic review

“…T h e s e a r c h r e t u r n e d 2 , carefully assessment of full text of the remaining 31 potentially eligible articles, 21 were excluded for the following reasons: (I) did not compare different PEEP levels (n=10); (II) ventilation in animals with existing lung injury (n=7); (III) immature animals (n=1); and (IV) other reasons (n=3). Thus, 10 trials including 284 animals remained (22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Table 1 summarizes characteristics of the included trials.…”

“…Table 1 summarizes characteristics of the included trials. Three trials used rats (23,25,28), three used pigs (26,27,30), two used rabbits (24,29), one used dogs (22) and one used horses (31). The median included animals were 8 in both PEEP arms.…”

“…Before randomization, in three trials a volume-controlled mode was used (22,26,27), in two a pressure-controlled mode (23,30), and in one a spontaneous breathing mode (31). After randomization, in four trials a volumecontrolled mode was used (22,26,27,31), and in two a pressure-controlled mode (23,30). For four trials it remained unclear which ventilation mode was used (24,25,28,29).…”

“…PEEP was most often 10 cmH 2 O in the 'high PEEP' or 'PEEP' arms (22,23,26,30), and most often 0 cmH 2 O in the 'low PEEP' or 'no PEEP' arms ( Table 1) (23,(25)(26)(27)(28). Interestingly, in three trials PEEP was 5 cmH 2 O in the 'high PEEP' or 'PEEP' arms (25,27,28), while in three other trials the same level of PEEP was used in the 'low PEEP' arms (29)(30)(31). In all trials, PEEP was fixed, except in one trial in which PEEP was titrated from 5 up to 20 cmH 2 O in 15 minutes intervals in the 'high PEEP' arm (31).…”

RC-3095, a Selective Gastrin-Releasing Peptide Receptor Antagonist, Does Not Protect the Lungs in an Experimental Model of Lung Ischemia-Reperfusion Injury

“…Several methods and substances have been used as an attempt to protect the lungs during the early phase of posttransplantation and to improve short- and long-term graft performance; however, these efforts have generated limited results [ 6 , 7 ]. The techniques include lung protective ventilation [ 8 , 9 ], appropriate fluid management, the optimization of organ preservation in lung transplantation, and the minimization of ventilation and anoxic ischemic time [ 10 ].…”