Effect of Posture on Lung and Regional Chest Wall Mechanics

Tachypnea and hypocapnia are induced by ‘buffeting’ in vehicles

“…In the absence of torso bending and twisting, simple lateral shifts as in our study appear to provoke little change in ventilation due to adaptability of chest wall mechanics [2]. Furthermore, G forces during hypergravity have minor effects upon respiratory mechanics [4] that are compensated for by small changes in inspiratory muscle activity [6].…”

Effect of age on pulmonary gas exchange during laparoscopy in the Trendelenburg lithotomy position

“…We measured arterial blood gases during the preinsufflation period in the supine lithotomy position (LP), a position that may affect P(a-ET) CO2 . Raising the legs in the LP has little effect on respiratory mechanics in awake subjects (7,8). During general anesthesia, this position may affect FRC and pulmonary blood volume, which would be attributable to a decrease in P(a-ET) CO2 .…”

“…With CO 2 insufflation in the Trendelenburg-lithotomy position, the setting of mechanical ventilation based on the value of PET CO2 should be determined with caution in elderly patients. Insufflation pressure; mmHg 13 (7)(8)(9)(10)(11)(12)(13)(14) 12 (9)(10)(11)(12)(13)(14) 12 (9)(10)(11)(12)(13)(14) Degree against horizontal line; degree 23 (14-30) 24.5 (14-32) 23 (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) N: number of patients…”

Adaptation of ventilation to ‘buffeting’ in vehicles

“…Thus, shorter, sharper inspirations would help protect against mechanical pumping of breathing [4], but at the cost of elevating ventilation, thereby producing hypocapnia. Although previous studies have largely excluded direct mechanical action on the torso as a source of interference with respiration [1,2,5] by the authors' experiences of being Ôwinded' by sudden jerks during a rough ride suggest that the sharp transients can significantly alter breathing; it is a question of how strong, how abrupt and how predictable.…”