BACKGROUND: The effects of hypercapnic acidosis on the diaphragm and its recovery to normocapnia have been poorly evaluated. The authors studied diaphragmatic contractility facing acute variations of arterial carbon dioxide tension (Paco2) and evaluated the contractile function at 60 min after normocapnia recovery. METHODS: Thirteen piglets weighing 15-20 kg were anesthetized, ventilated, and separated into two groups: a control group (n = 5) evaluated in normocapnia (time-control experiments) and a hypercapnia group (n = 8) in which animals were acutely and shortly exposed to five consecutive ranges of Paco2 (40, 50, 70, 90, and 110 mmHg). Then carbon dioxide insufflation was stopped. Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure variations obtained after bilateral transjugular phrenic nerve pacing at increased frequencies (20-120 Hz). For each level of arterial pressure of carbon dioxide, pressure-frequency curves were obtained in vivo by phrenic nerve pacing. RESULTS: In the hypercapnia group, mean +/- SD transdiaphragmatic pressure significantly decreased from 41 +/- 3 to 29 +/- 3 cm H2O (P < 0.05) between the first (40 mmHg) and fifth (116 mmHg) stages of capnia at the frequency of 100 Hz stimulation. The observed alteration of the contractile force was proportional to the level of Paco2 (r = 0.61, P < 0.01). Normocapnia recuperation allowed a partial recovery of the diaphragmatic contractile force (80% of the baseline value) at 60 min after carbon dioxide insufflation interruption. CONCLUSION: A short exposure to respiratory acidosis decreased diaphragmatic contractility proportionally to the degree of hypercapnia, and this alteration was only partially reversed at 60 min after exposure.
BACKGROUND: The effects of hypercapnic acidosis on the diaphragm and its recovery to normocapnia have been poorly evaluated. The authors studied diaphragmatic contractility facing acute variations of arterial carbon dioxide tension (Paco2) and evaluated the contractile function at 60 min after normocapnia recovery. METHODS: Thirteen piglets weighing 15-20 kg were anesthetized, ventilated, and separated into two groups: a control group (n = 5) evaluated in normocapnia (time-control experiments) and a hypercapnia group (n = 8) in which animals were acutely and shortly exposed to five consecutive ranges of Paco2 (40, 50, 70, 90, and 110 mmHg). Then carbon dioxide insufflation was stopped. Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure variations obtained after bilateral transjugular phrenic nerve pacing at increased frequencies (20-120 Hz). For each level of arterial pressure of carbon dioxide, pressure-frequency curves were obtained in vivo by phrenic nerve pacing. RESULTS: In the hypercapnia group, mean +/- SD transdiaphragmatic pressure significantly decreased from 41 +/- 3 to 29 +/- 3 cm H2O (P < 0.05) between the first (40 mmHg) and fifth (116 mmHg) stages of capnia at the frequency of 100 Hz stimulation. The observed alteration of the contractile force was proportional to the level of Paco2 (r = 0.61, P < 0.01). Normocapnia recuperation allowed a partial recovery of the diaphragmatic contractile force (80% of the baseline value) at 60 min after carbon dioxide insufflation interruption. CONCLUSION: A short exposure to respiratory acidosis decreased diaphragmatic contractility proportionally to the degree of hypercapnia, and this alteration was only partially reversed at 60 min after exposure.
Authors: V J Cardenas; J B Zwischenberger; W Tao; P D Nguyen; T Schroeder; L D Traber; D L Traber; A Bidani Journal: Crit Care Med Date: 1996-05 Impact factor: 7.598
Authors: Boris Jung; Thomas Rimmele; Charlotte Le Goff; Gérald Chanques; Philippe Corne; Olivier Jonquet; Laurent Muller; Jean-Yves Lefrant; Christophe Guervilly; Laurent Papazian; Bernard Allaouchiche; Samir Jaber Journal: Crit Care Date: 2011-10-13 Impact factor: 9.097
Authors: Willem-Jan M Schellekens; Hieronymus W H van Hees; Matthijs Kox; Marianne Linkels; Gilberto L Andrade Acuña; P N Richard Dekhuijzen; Gert Jan Scheffer; Johannes G van der Hoeven; Leo M A Heunks Journal: Crit Care Date: 2014-02-09 Impact factor: 9.097
Authors: Christian S Bruells; Ingmar Bergs; Rolf Rossaint; Jun Du; Christian Bleilevens; Andreas Goetzenich; Joachim Weis; Michael P Wiggs; Scott K Powers; Marc Hein Journal: PLoS One Date: 2014-01-27 Impact factor: 3.240