Martin 2013 Crit Care Med
|Martin AD, Joseph AM, Beaver TM, Smith BK, Martin TD, Berg K, Hess PJ, Deoghare HV, Leeuwenburgh C (2013) Effect of intermittent phrenic nerve stimulation during cardiothoracic surgery on mitochondrial respiration in the human diaphragm. Crit Care Med 42:e152-6.|
Martin AD, Joseph AM, Beaver TM, Smith BK, Martin TD, Berg K, Hess PJ, Deoghare HV, Leeuwenburgh C (2013) Crit Care Med
Abstract: Recent studies have shown that brief periods of mechanical ventilation in animals and humans can lead to ventilator-induced diaphragmatic dysfunction, which includes muscle atrophy, reduced force development, and impaired mitochondrial function. Studies in animal models have shown that short periods of increased diaphragm activity during mechanical ventilation support can attenuate ventilator-induced diaphragmatic dysfunction but corresponding human data are lacking. The purpose of this study was to examine the effect of intermittent diaphragm contractions during cardiothoracic surgery, including controlled mechanical ventilation, on mitochondrial respiration in the human diaphragm.
Within subjects repeated measures study.
Operating room in an academic health center.
Five subjects undergoing elective cardiothoracic surgery.
In patients (age 65.6 ± 6.3 yr) undergoing cardiothoracic surgery, one phrenic nerve was stimulated hourly (30 pulses/min, 1.5 msec duration, 17.0 ± 4.4 mA) during the surgery. Subjects received 3.4 ± 0.6 stimulation bouts during surgery. Thirty minutes following the last stimulation bout, samples of diaphragm muscle were obtained from the anterolateral costal regions of the stimulated and inactive hemidiaphragms.
Mitochondrial respiration was measured in permeabilized muscle fibers with high-resolution respirometry. State III mitochondrial respiration rates (pmol O2/s/mg wet weight) were 15.05 ± 3.92 and 11.42 ± 2.66 for the stimulated and unstimulated samples, respectively (p < 0.05). State IV mitochondrial respiration rates were 3.59 ± 1.25 and 2.11 ± 0.97 in the stimulated samples and controls samples, respectively (p < 0.05).
These are the first data examining the effect of intermittent contractions on mitochondrial respiration rates in the human diaphragm following surgery/mechanical ventilation. Our results indicate that very brief periods (duty cycle ~1.7%) of activity can improve mitochondrial function in the human diaphragm following surgery/mechanical ventilation. • Keywords: Diaphragm stimulation, Mechanical ventilation, Mitochondrial respiration, Phrenic nerve, Thoracic surgery, Ventilator-induced diaphragm dysfunction, Buffer z
• O2k-Network Lab: US FL Gainesville Leeuwenburgh C
Labels: MiParea: Respiration, mt-Medicine, Patients
Organism: Human Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue
Coupling state: LEAK, OXPHOS Pathway: NS HRR: Oxygraph-2k