title: Kinetics of ventilation-induced changes in diaphragmatic metabolism by bilateral phrenic pacing in a piglet model.
abstract: Perioperative necessity of deep sedation is inevitably associated with diaphragmatic inactivation. This study investigated 1) the feasibility of a new phrenic nerve stimulation method allowing early diaphragmatic activation even in deep sedation and, 2) metabolic changes within the diaphragm during mechanical ventilation compared to artificial activity. 12 piglets were separated into 2 groups. One group was mechanically ventilated for 12 hrs (CMV) and in the second group both phrenic nerves were stimulated via pacer wires inserted near the phrenic nerves to mimic spontaneous breathing (STIM). Lactate, pyruvate and glucose levels were measured continuously using microdialysis. Oxygen delivery and blood gases were measured during both conditions. Diaphragmatic stimulation generated sufficient tidal volumes in all STIM animals. Diaphragm lactate release increased in CMV transiently whereas in STIM lactate dropped during this same time point (2.6 vs. 0.9 mmol L-1after 5:20 hrs; p < 0.001). CMV increased diaphragmatic pyruvate (40 vs. 146 μmol L-1after 5:20 hrs between CMV and STIM; p < 0.0001), but not the lactate/pyruvate ratio. Diaphragmatic stimulation via regular electrodes is feasible to generate sufficient ventilation, even in deep sedation. Mechanical ventilation alters the metabolic state of the diaphragm, which might be one pathophysiologic origin of ventilator-induced diaphragmatic dysfunction. Occurrence of hypoxia was unlikely.
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.|Department of Intensive and Intermediate Care, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Breuer
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Nima
authors.initials: N
authors.lastname: Hatam
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Grabiger
authors.affiliation: Department of Intensive and Intermediate Care, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Gernot
authors.initials: G
authors.lastname: Marx
authors.affiliation: Department of Kinesiology, Johnson Cancer Research Institute, Kansas State University, Manhattan, Kansas, USA.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Behnke
authors.affiliation: Institute of Neuropathology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Weis
authors.affiliation: Department of Intensive and Intermediate Care, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Ruedger
authors.initials: R
authors.lastname: Kopp
authors.affiliation: Laboratory of Pneumology, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Gayan-Ramirez
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.|Department of Anaesthesiology, Sankt Elisabeth Hospital, Gütersloh, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Zoremba
authors.affiliation: Department of Intensive and Intermediate Care, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Christian S
authors.initials: CS
authors.lastname: Bruells
mesh_terms: D000818:Animals; D003964:Diaphragm / Q000378:metabolism*; D005947:Glucose / Q000032:analysis; D007773:Lactates / Q000032:analysis; D010791:Phrenic Nerve; D012123:Pulmonary Ventilation; D011773:Pyruvates / Q000032:analysis; D012121:Respiration, Artificial; D013552:Swine; D004561:Transcutaneous Electric Nerve Stimulation
chemical_list: D007773:Lactates; D011773:Pyruvates; D005947:Glucose