Comparison of the Effects of Endotracheal Intubation of Wistar Rats Using the Conventional Technique vs. a New Modified Technique Using a 3D Mouth-Piece.

AIMS: Endotracheal intubation in rats is challenging due to the difficult anatomical characteristics of the airway. The success rate at first attempt is low and airway damage is a common complication. We aimed to compare and evaluate the conventional intubation method with a modified procedure using an inclined plate, headlamp (700-Lumen), and 3D mouth-piece designed with a 20° curvature. Both techniques were conducted by laboratory personnel with and without previous experience in airway management of laboratory rats. MATERIAL AND METHODS: In this study, we used 36 Wistar rats of both genders. Three groups of laboratory personnel (anesthesiologists, medical students, and laboratory technicians) performed both endotracheal intubation techniques, i.e., blind intubation at supine position and endotracheal intubation at 70° supine position with a 3D mouth-piece and direct illumination of the glottis. RESULTS: The modified technique had a significantly higher success rate and shorter procedure duration. Moreover, there was no significant difference in the procedure duration between personnel with and without previous training in airway management. CONCLUSION: Previous knowledge and experience in airway management are required when performing conventional endotracheal intubation; moreover, its success rate is low. Contrastingly, using proper instruments and the 3D mouth-piece facilitated easier and quicker airway management regardless of previous experience.

Comparative Study of Capillary Filtration Coefficient (Kfc) Determination by a Manual and Automatic Perfusion System. Step by Step Technique Review.

The purpose of calculating the capillary filtration coefficient is to experimentally evaluate edema formation in models of pulmonary ischemia-reperfusion injury. For many years, the obtaining of this coefficient implies a series of manual maneuvers during ex-vivo reperfusion of pulmonary arterial pressure, venous pressure and weight, as well as the calculation of the Kfc formula. Through automation, the calculation of capillary filtration coefficient could be easier and more efficient. To describe an automatic method designed in our laboratory to calculating the capillary filtration coefficient and compare with traditional determination of capillary filtration coefficient as gold standard method. An automatic three valve perfusion system was constructed, commanded by a mastery module connected to a graphical user interface. To test its accuracy, cardiopulmonary blocks of Wistar rats were harvested and distributed in manual (n=8) and automated (n=8) capillary filtration coefficient determination groups. Physiological parameters as pulmonary arterial pressure, pulmonary venous pressure, weight and capillary filtration coefficient were obtained. Results: Capillary filtration coefficient, pulmonary arterial pressure, venous arterial pressure shown no statistical significance difference between the groups. The automated perfusion system for obtaining Kfc was standardized and validated, giving reliable results without biases and making the process more efficient in terms of time and personal staff.

Effects of Sildenafil and Tadalafil on Edema and Reactive Oxygen Species Production in an Experimental Model of Lung Ischemia-Reperfusion Injury.

BACKGROUND: Lung ischemia-reperfusion injury is characterized by formation of reactive oxygen species and cellular swelling leading to pulmonary edema and primary graft dysfunction. Phosphodiesterase 5 inhibitors could ameliorate lung ischemia-reperfusion injury by interfering in many molecular pathways. The aim of this work was to evaluate and compare the effects of sildenafil and tadalafil on edema and reactive oxygen species formation in an ex vivo nonhuman animal model of lung ischemia-reperfusion injury. METHODS: Thirty-two Wistar rats were distributed, treated, perfused and the cardiopulmonary blocks were managed as follows: control group: immediate excision and reperfusion without pretreatment; ischemia reperfusion group: treatment with dimethylsulfoxide 0.9% and excision 1 hour later; sildenafil group: treatment with sildenafil (0.7 mg/kg) and excision 1 hour later; and tadalafil group: treatment with tadalafil (0.15 mg/kg) and excision 2 hours later. All cardiopulmonary blocks except control group were preserved for 8 hours and then reperfused. Pulmonary arterial pressure, pulmonary venous pressure, and capillary filtration coefficient were measured. Reactive oxygen species were measured. RESULTS: Edema was similar between control and sildenafil groups, but significantly greater in the ischemia-reperfusion (P ≤ .04) and tadalafil (P ≤ .003) groups compared with the sildenafil group. The malondialdehyde levels were significantly lower in the sildenafil (P ≤ .001) and tadalafil (P ≤ .001) groups than the ischemia-reperfusion group. CONCLUSIONS: Administration of sildenafil, but not tadalafil, decreased edema in lung ischemia-reperfusion injury. Both drugs decreased reactive oxygen species formation in a lung ischemia-reperfusion injury model.