Cervical ultrasound for endotracheal intubation confirmation in dogs by veterinary students: a cadaveric study.

Although endotracheal intubation is usually a simple and fast procedure in dogs, some situations can be challenging and lead to the risk of tube misplacement in the esophagus-a life-threatening complication. Hence, confirming intubation is a cornerstone whenever this procedure is performed. Methods such as direct visualization or capnography present limitations insofar as they may be unreliable or unavailable under some circumstances. Ultrasound has emerged as a promising tool to confirm intubation in medicine. However, so far little research has been done on the subject in veterinary medicine. This study's main goal was to investigate ultrasound performed by veterinary students as a confirmation method for intubation in canine cadavers after a brief training session (25 minutes). A total of 160 exams were performed with a microconvex probe by 20 students in 11 different cadavers on left and right recumbencies. Overall accuracy was 70.6% with a median success rate of 75% and a median time to diagnosis of 25 seconds. The number of correct diagnoses was statistically higher than the wrong ones (p<0.05) without difference between recumbencies. Sensitivity, specificity, and positive and negative predictive values were 72.5%, 68.8%, 69.9%, and 71.4%, respectively. The fastest diagnosis was performed in just 4 seconds, and among the top-performers, one student had 100% accuracy with a mean time to diagnosis of 16.8 seconds, and four students had approximately 88% accuracy. This study showed for the first time that even inexperienced veterinary students can have acceptable accuracy in confirming endotracheal intubation in dogs after a brief training session.

Apesar de a intubação endotraqueal em cães ser frequentemente um procedimento simples e rápido, algumas situações podem ser desafiadoras e levar ao risco de posicionamento da sonda no esôfago - uma grave complicação. Portanto, a confirmação da intubação é uma etapa crucial sempre que o procedimento for realizado. Métodos como visualização direta ou capnografia apresentam limitações e podem ser pouco confiáveis ou indisponíveis sob certas circunstâncias. A ultrassonografia surgiu como uma ferramenta promissora para confirmação da intubação na medicina. Contudo, até o momento pouco foi estudado na veterinária. O objetivo deste estudo foi investigar a ultrassonografia realizada por estudantes de veterinária como método de confirmação para a intubação em cadáveres caninos após um breve treinamento (25 minutos). Foram realizados 160 exames com transdutor microconvexo por 20 estudantes em 11 cadáveres nos decúbitos direito e esquerdo. A acurácia geral foi 70.6% com medianas de taxa de sucesso de 75% e de tempo para diagnóstico de 25 segundos. O número de diagnósticos corretos foi estatisticamente superior aos errados (p<0.05) sem diferença entre decúbitos. Sensibilidade, especificidade, valor preditivo positivo e negativo foram, respectivamente: 72.5%; 68.8%; 69.9% e 71.4%. O diagnóstico mais rápido se deu em 4 segundos e entre os estudantes com melhor performance, um se destacou com 100% de acurácia e tempo médio para diagnóstico de 16.8 segundos enquanto quatro outros obtiveram 88% de acurácia. Este estudo demonstrou pela primeira vez que mesmo estudantes de veterinária inexperientes podem atingir uma acurácia aceitável na confirmação da intubação endotraqueal em cães após um breve treinamento.

Fluid management strategies and their interaction with mechanical ventilation: from experimental studies to clinical practice.

Patients on mechanical ventilation may receive intravenous fluids via restrictive or liberal fluid management. A clear and objective differentiation between restrictive and liberal fluid management strategies is lacking in the literature. The liberal approach has been described as involving fluid rates ranging from 1.2 to 12 times higher than the restrictive approach. A restrictive fluid management may lead to hypoperfusion and distal organ damage, and a liberal fluid strategy may result in endothelial shear stress and glycocalyx damage, cardiovascular complications, lung edema, and distal organ dysfunction. The association between fluid and mechanical ventilation strategies and how they interact toward ventilator-induced lung injury (VILI) could potentiate the damage. For instance, the combination of a liberal fluids and pressure-support ventilation, but not pressure control ventilation, may lead to further lung damage in experimental models of acute lung injury. Moreover, under liberal fluid management, the application of high positive end-expiratory pressure (PEEP) or an abrupt decrease in PEEP yielded higher endothelial cell damage in the lungs. Nevertheless, the translational aspects of these findings are scarce. The aim of this narrative review is to provide better understanding of the interaction between different fluid and ventilation strategies and how these interactions may affect lung and distal organs. The weaning phase of mechanical ventilation and the deresuscitation phase are not explored in this review.

Effects of different fluid management on lung and kidney during pressure-controlled and pressure-support ventilation in experimental acute lung injury.

Optimal fluid management is critical during mechanical ventilation to mitigate lung damage. Under normovolemia and protective ventilation, pulmonary tensile stress during pressure-support ventilation (PSV) results in comparable lung protection to compressive stress during pressure-controlled ventilation (PCV) in experimental acute lung injury (ALI). It is not yet known whether tensile stress can lead to comparable protection to compressive stress in ALI under a liberal fluid strategy (LF). A conservative fluid strategy (CF) was compared with LF during PSV and PCV on lungs and kidneys in an established model of ALI. Twenty-eight male Wistar rats received endotoxin intratracheally. After 24 h, they were treated with CF (minimum volume of Ringer's lactate to maintain normovolemia and mean arterial pressure ≥70 mmHg) or LF (~4 times higher than CF) combined with PSV or PCV (VT  = 6 ml/kg, PEEP = 3 cmH2 O) for 1 h. Nonventilated animals (n = 4) were used for molecular biology analyses. CF-PSV compared with LF-PSV: (1) decreased the diffuse alveolar damage score (10 [7.8-12] vs. 25 [23-31.5], p = 0.006), mainly due to edema in axial and alveolar parenchyma; (2) increased birefringence for occludin and claudin-4 in lung tissue and expression of zonula-occludens-1 and metalloproteinase-9 in lung. LF compared with CF reduced neutrophil gelatinase-associated lipocalin and interleukin-6 expression in the kidneys in PSV and PCV. In conclusion, CF compared with LF combined with PSV yielded less lung epithelial cell damage in the current model of ALI. However, LF compared with CF resulted in less kidney injury markers, regardless of the ventilatory strategy.