The impact of diaphragm management on prolonged ventilator support after thoracoabdominal aortic repair.
OBJECTIVE
The relationship of the division of the diaphragm during thoracoabdominal aortic repair to prolonged ventilator support has not been studied. The purpose of this study was (1) to determine whether preservation of diaphragm integrity has a significant effect on postoperative ventilator duration and (2) to elucidate other pulmonary risk factors related to thoracoabdominal aortic surgery and to study the relationship of these factors to the intact diaphragm technique.


METHODS
Between February 1991 and January 1997, we repaired 397 descending and thoracoabdominal aortic aneurysms. Descending thoracic aneurysms were not included in the study because their repair does not include the diaphragm. A total of 256 patients participated in this study. The diaphragm was divided in 150 patients and left intact in 106 patients. Examined as potential risk factors were patient demographics, history and physical findings, aneurysm extent, urgency of the procedure, acute dissection, cross-clamp time, homologous and autologous blood product consumption, and adjunctive operative techniques. FEV1 also was considered in the 197 patients for whom preoperative spirometry was available. Prolonged mechanical ventilation was defined as ventilator support for >72 hours. Data were analyzed by univariate contingency table and multiple logistic regression methods.


RESULTS
Increasing age (odds ratio [OR], 1.02/y; P <.02), current smoking (OR, 2.6; P <.0008), total cross-clamp time (OR, 1.0/min; P <.008), units packed red blood cells transfused (OR, 1.06/unit; P <.008), and division of the diaphragm (OR, 2.03; P <.02) were significant, independent predictors of prolonged ventilation. Sixty-seven percent of patients (71 of 106) whose diaphragms were preserved were extubated in <72 hours compared with 52% of patients (78 of 150) who underwent diaphragm division (OR, 0.53; P <.02).


CONCLUSIONS
Independently of well known pulmonary risk factors, an intact diaphragm during thoracoabdominal aortic repair results in a higher probability of early ventilator weaning.
Engle
J
J
Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA.
Safi
H J
HJ
Miller
C C
CC
Campbell
M P
MP
Harlin
S A
SA
Letsou
G V
GV
Lloyd MD
K S
KS
Root
D B
DB
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001012:Aorta, Abdominal / Q000601:surgery; D001013:Aorta, Thoracic / Q000601:surgery; D001014:Aortic Aneurysm / Q000601:surgery*; D002648:Child; D003964:Diaphragm / Q000601:surgery*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014656:Vascular Surgical Procedures / Q000379:methods; D015300:Ventilator Weaning