Effects of split torso positioning and laparoscopic surgery for donor nephrectomy on respiratory mechanics.
OBJECTIVE
To test whether split torso positioning, abdominal insufflation, and other procedures performed during laparoscopic nephrectomy would affect mechanical impedances to inflation [i.e., elastance (E) and resistance (R) of the total respiratory system (Ers, and Rrs), lungs (EL and RL), and chest wall (Ecw and Rcw)] differently from previously studied laparoscopic procedures.


METHODS
Unblinded study, each patient serving as own control.


METHODS
University hospital.


METHODS
12 ASA physical status I and II patients scheduled for laparoscopic donor nephrectomy, all without cardiopulmonary disease.


METHODS
Patients were anesthetized and paralyzed, tracheally intubated and mechanically ventilated at 10, 20, and 30 breaths/minute and at tidal volumes of 250, 500, and 800 ml. Measurements were made in the following positions: supine, split torso, abdominal insufflation (Pab = 15 mmHg), and supine after deflation.


RESULTS
Airway flow and pressure and esophageal pressure were measured. Discrete Fourier transformation was used to calculate E and R. These were analyzed with repeated measures, linear multiple regression with accepted level of significance at p < 0.05. Ers, Ecw, and Rcw increased (p < 0.05) while EL decreased (p < 0.05) when patients changed from supine to split torso. During Pab = 15 mmHg, Ers, Ecw, and Rcw increased further and Rrs and RL increased (p < 0.05). Following abdominal deflation, Ecw and Ers remained elevated (p < 0.05). The changes in Ecw caused by laparoscopy and surgery were greater than we have previously measured in other laparoscopic procedures, while the changes in EL were less.


CONCLUSIONS
Laparoscopic nephrectomy affects lung and chest wall mechanical properties differently from other laparoscopic procedures. This finding could be due to the split torso positioning, and the effects of abdominal swelling on the chest wall caused by administration of more perioperative fluids with laparoscopic nephrectomy.
Fahy
B G
BG
Department of Anesthesiology, University of Maryland, Baltimore 21201-1595, USA.
Barnas
G M
GM
Flowers
J L
JL
Jacobs
S C
SC
Plotkin
J S
JS
Delaney
P A
PA
D000328:Adult; D000403:Airway Resistance / Q000502:physiology; D000769:Anesthesia, Inhalation; D001794:Blood Pressure / Q000502:physiology; D004548:Elasticity; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D010100:Oxygen / Q000097:blood; D011187:Posture / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*; D014019:Tissue Donors
D010100:Oxygen