Clinical Surgery-American
Impact of intraoperative myocardial tissue acidosis on
postoperative adverse outcomes and cost of care for
patients undergoing prolonged aortic clamping during
cardiopulmonary bypass
Christine M. Healey, M.S.
a,b,
*, Dharam J. Kumbhani, M.D., S.M.
a
,
Nancy A. Healey, B.S.
a
, Michael D. Crittenden, M.D.
a,c,d
, Stephen F. Gibson, Ph.D.
a
,
Shukri F. Khuri, M.D.
a,c,d
a
Cardiothoracic Surgery (112), VA Boston Healthcare System, 1400 VFW Pkwy., West Roxbury, MA 02132, USA;
b
Albany Medical College, Albany, NY, USA;
c
Harvard Medical School, Boston, MA, USA;
d
Brigham and Women’s
Hospital, Boston, MA, USA
Abstract
BACKGROUND: This study examined the impact of intraoperative myocardial acidosis and adverse
postoperative outcomes on the cost of cardiac surgical care.
METHODS: Myocardial tissue pH corrected to 37°C (pH
37C
) was measured in 162 patients with
cross-clamp (XC) duration of 119 minutes or longer. Perioperative data and outcomes were collected
prospectively. The Veterans Affairs cost accounting system was used to determine the cost of care in
a subset of 57 patients.
RESULTS: Long XC duration was associated with significantly increased acidosis and adverse
postoperative outcomes. The cost of care for patients with adverse outcomes was increased by 110%
(P .0001). Patients with acidosis at the end of reperfusion had significantly (P = .0470) increased
costs of care. End reperfusion of myocardial tissue pH
37C
of less than 7.0, diabetes mellitus, and body
surface area were significant determinants of postoperative adverse outcomes.
CONCLUSIONS: Intraoperative myocardial acidosis is a determinant of postoperative adverse out-
comes and cost in cardiac surgery. Reducing XC duration and improving intraoperative myocardial
protection should improve outcomes and reduce cost.
© 2009 Published by Elsevier Inc.
KEYWORDS:
Aortic cross-clamp;
Ischemia;
Reperfusion;
Outcomes;
Cost
The duration of aortic cross-clamp (XC) during cardiac
surgery has been associated with the occurrence of adverse
postoperative events.
1–7
In a study of patients aged 80 and
older, Deiwick et al
8
reported that prolonged aortic clamp-
ing, among other factors, was an important determinant of
the number of postoperative complications. Rady et al
9
found an aortic XC time of more than 120 minutes to be one
of the main determinants of postoperative mortality in pa-
tients age 75 or older. A surgical ischemic time of more than
77 minutes was reported by Flameng et al
10
to be one of the
most important predictors of clinical outcome after com-
bined valve and coronary bypass procedures. Combined
Presented at the Association of VA Surgeons, May 10 –12, 2007, Little
Rock, AR.
* Corresponding author. Tel.: +1-857-203-5262; fax: +1-857-203-5738.
E-mail address: nancy.healy@va.gov
Manuscript received August 23, 2007; revised manuscript January 8,
2008
0002-9610/$ - see front matter © 2009 Published by Elsevier Inc.
doi:10.1016/j.amjsurg.2008.01.023
The American Journal of Surgery (2009) 197, 203–210