A review of the effects of some endocrinological factors on respiratory mechanics

Abstract

A number of molecules of biological interest exhibit unexpected influences on respiratory mechanics. The clinical effects depend on the consequences of modified inspiratory pressure values the respiratory muscles have to perform for a given breathing pattern.

The effects of nifedipine on respiratory mechanics investigated by theend-inflation occlusion method in the rat

“…The mean values of respiratory system mechanics parameters reported here ( Table 1 ) are comprised in the range of those previously measured by the same techniques in rats by various authors working in different laboratories 9–16 , 18 , 22 . The presently measured respiratory mechanics parameters have been widely investigated previously 16–19 , 22 , and represent the most useful data in order to assess a possible respiratory system mechanical impairment.…”

“…Modelling the respiratory system as consisting of two distinct compartments, the end-inflation occlusion method has been widely used to study respiratory mechanics in experimental animals 9–16 . Ideally, the inflation flow should stop instantaneously, but this is practically impossible to achieve.…”

“…Positive pressure ventilation was maintained for 5 min and respiratory mechanics were then measured using the end-inflation occlusion method 9–16 . The ventilator was disconnected, PEEP was discontinued, and the tracheal cannula was connected to a constant flow pump (SP 2000 Series Syringe Pump sp210iw, World Precision Instruments, Sarasota, FL) set to deliver a tidal volume (VT) of 3 ml with a square wave flow (F) of 4 ml/s.…”

“…The end-inflation occlusion method was utilised to determine respiratory mechanics parameters 9–16 . The static elastic pressure of the respiratory system (Pel,rs) and the sudden Newtonian resistive pressure drop at flow interruption (Pmin,rs) were measured on adequately magnified tracings ( Figure 1 ).…”