Alteration in Diaphragmatic Function Induced by Acute Necrotizing Pancreatitis in a Rodent Model

Abstract

Some of the common complications of acute necrotizing pancreatitis also involve pulmonary complications. These manifestations are often associated with a cephalad diaphragmatic shift. We hypothized that diaphragmatic function might be directly compromised by the acute abdominal process. This hypothesis was tested on an acute necrotizing pancreatitis (ANP) rat model. We assessed the diaphragm and peripheral (Extensor Digitorum Longus and Soleus) muscle properties in vitro using strips in control (C) and ANP animals. Contractile parameters included single twitch and a force-frequency curve (10 to 100 Hz), and an endurance capacity index (T50%) was calculated after a repetitive stimulation (30 Hz). Breathing pattern was not different between control and ANP animals, and muscular histologic examination was normal. However, ANP was associated with a marked decrease in diaphragmatic strength for all frequencies of stimulation when compared with C. Endurance capacity was also reduced in ANP animals as assessed by a lower T50% (ANP: 31 +/- 10.5 s; C: 49 +/- 10.3 s; p < 0.05). By contrast, no significant change in peripheral muscle function was observed in both groups. We conclude that ANP causes impairment in diaphragmatic strength and endurance capacity, whereas peripheral muscles are spared. These findings suggest that alterations in the respiratory pump may be involved in the genesis of acute respiratory failure in ANP.

Noninvasive Positive Pressure Ventilation in Patients with Respiratory Failure due to Severe Acute Pancreatitis

“…Atelectasis, alveolar flooding [29], alteration in diaphragmatic function [30] and systemic inflammatory response syndrome [31] contribute to the development of ARF. The use of NPPV with pressure support ventilation and PEEP allows for increased lung volume with reexpansion of atelectasis [32], decreased work of breathing [14, 33] and pulmonary extravascular water [34].…”

“…Alteration in diaphragmatic function in AP could also be a possible mechanism responsible for its cephalad displacement and occurrence of atelectasis. In experimental studies, Matuszczak et al [30] reported that an edematous pancreatitis rat model induced marked alteration in diaphragmatic function, whereas there was no change in peripheral muscle contractility. …”

Lung Infection and the Diaphragm

“…This is also probably true in the case of abdominal disorders. Diaphragmatic histology was normal and muscular levels of myeloperoxidase, a marker of neutrophil infiltration, did not increase in either the muscle of the Pseudomonas-infected animals (2) or in animals with pancreatitis and peritonitis (3,5), thus excluding direct extension of the infectious/inflammatory process to the muscle. Anatomical proximity to the infectious site could, however, be responsible for direct exposure of the diaphragm to bacteria and/or inflammatory mediators synthesized in the infected organ via direct lymphatic spread (8).…”

Efficacy of tocilizumab treatment in cerulein-induced experimental acute pancreatitis model in rats

“…Damaged tissue releases chemotactic factors that accumulate neutrophils. Gathered neutrophils blocks the lumen and increase the release of enzymes, free oxygen radicals, and other inflammatory mediators such as protease and elastase (22). All these events incessantly trigger each other, leading to a vicious cycle.…”