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Summary Background It is common practice during one lung ventilation (OLV) to use 100% oxygen, although this may cause hyperoxia- and oxidative stress-related lung injury. We hypothesized that lower oxygen (FiO2) during OLV will result in less inflammatory and oxidative lung injury and improved lung function. Methods Twenty pigs (8.88 ± 0.84 kg; 38 ± 4.6 days) were assigned to either the hyperoxia group (n = 10; FiO2 = 100%) or the normoxia group (n = 10; FiO2 < 50%). Both groups were subjected to 3 hr of OLV. Blood samples were tested for pro-inflammatory cytokines and lung tissue was tested for these cytokines and oxidative biomarkers. Results There were no differences between groups for partial pressure of CO2, tidal volume, end-tidal CO2, plasma cytokines, or respiratory compliance. Total respiratory resistance was greater in the hyperoxia group (P = 0.02). There were higher levels of TNF-α, IL-1β, and IL-6 in the lung homogenates of the hyperoxia group than in the normoxia group (P ≤ 0.01, 0.001, and 0.001, respectively). Myeloperoxidase and protein carbonyls (PC) were higher (P = 0.03 and P = 0.01, respectively) and superoxide dismutase (SOD) was lower in the lung homogenates of the hyperoxia group (P ≤ 0.001). Conclusion Higher myeloperoxidase, PC, and cytokine levels, and lower SOD availability indicate a greater degree of injury in the lungs of the hyperoxia animals, possibly from using 100% oxygen. In this translational study using a pig model, FiO2 ≤ 50% during OLV reduced hyperoxic injury and improved function in the lungs.

Background:We have demonstrated effectiveness of an aerosolized, peptide-containing, synthetic surfactant (KL 4 surfactant), in spontaneously breathing CPAP-supported preterm lambs. Dose-ranging studies are required to define the dose that produces optimal physiologic and biomarker responses.

The in vivo ovine model provides a clinically relevant platform to study cardiopulmonary mechanisms and treatments of disease; however, a robust ovine primary alveolar epithelial type II (ATII) cell culture model is lacking. The objective of this study was to develop and optimize ovine lung tissue cryopreservation and primary ATII cell culture methodologies for the purposes of dissecting mechanisms at the cellular level to elucidate responses observed in vivo. To address this, we established in vitro submerged and air-liquid interface cultures of primary ovine ATII cells isolated from fresh or cryopreserved lung tissues obtained from mechanically ventilated sheep (128 days gestation—6 months of age). Presence, abundance, and mRNA expression of surfactant proteins was assessed by immunocytochemistry, Western Blot, and quantitative PCR respectively on the day of isolation, and throughout the 7 day cell culture study period. All biomarkers were significantly greater from cells isolated from fresh than cryopreserved tissue, and those cultured in air-liquid interface as compared to submerged culture conditions at all time points. Surfactant protein expression remained in the air-liquid interface culture system while that of cells cultured in the submerged system dissipated over time. Despite differences in biomarker magnitude between cells isolated from fresh and cryopreserved tissue, cells isolated from cryopreserved tissue remained metabolically active and demonstrated a similar response as cells from fresh tissue through 72 hr period of hyperoxia. These data demonstrate a cell culture methodology using fresh or cryopreserved tissue to support study of ovine primary ATII cell function and responses, to support expanded use of biobanked tissues, and to further understanding of mechanisms that contribute to in vivo function of the lung.

Preterm infants lack necessary thermoregulation. An ideal incubator should maintain a uniform and constant thermal environment. We compared the effectiveness of a supplemental heating blanket to improve the heating characteristics of two different incubator warming devices using assessment of their respective function alone as controls. Device A and device B, with and without a heating blanket (Harvard Apparatus), were instrumented with a distribution matrix of multiple temperature (n = 11) and humidity probes. These data were serially measured during warm up to 37.5 °C and through a series of open-door perturbations. The time constant, temperature variation, and change in air temperature were calculated. Data were analyzed for significance by 2-factor ANOVA for each respective incubator either turned on or off with either the heating blanket turned on or off. Device A warms faster (33.87% ; p < 0.05) than device B, but has a greater (37.27% ; p < 0.05) temperature variation during warmup. The heating blanket enhances the thermal response of device A during warmup, but does not alter those of device B. With the side door open, device A shows a smaller (−16.5% ; p < 0.05) temperature variation than device B; the heating blanket attenuates the temperature change in both devices. These results demonstrate that the use of a supplemental heating blanket, as well as device-related differences, may impact clinical control of a thermal environment.