Linda L. Liu, M.D.
Assistant Clinical Professor
University of California, San Francisco
505 Parnassus Ave, Box 0624
San Francisco, CA 94143
liul@anesthesia.ucsf.edu
Jacqueline M. Leung, M.D., M.P.H.
Associate Professor University of California, San Francisco
505 Parnassus Ave, Box 0648
San Francisco, CA 94143
leungj@anesthesia.ucsf.edu
Introduction
By the year 2030, it is estimated that 20 percent of Americans
will be older than 65, while one out of four elderly individuals
will be older than 85 years of age. Twenty-one percent of those
over age 60 will undergo surgery and anesthesia as compared
with only 12 percent of those aged 45 to 60 years. Despite the
higher numbers of elderly patients having surgery, mortality
and morbidity rates have been declining. Old age appears to
have assumed less influence as a determinant of adverse outcome
as perioperative care has improved. A better understanding of
the associated risk factors leading to perioperative complications
may help anesthesia providers to further lower the risk. This
chapter will review recent studies examining common perioperative
adverse events in elderly patients and their associated risk
factors.
Mortality
Recent studies have shown a decline in the perioperative mortality
rates from 20 percent in the 1960s to 10 percent in the 1970s,
and to 5-6 percent in the 1980s. This trend of declining mortality
rates even extends to those on the extreme end of the age spectrum.
For example, a study by Warner from 1998 reported on 31 patients
over 100 years of age.1 The patients
had postoperative mortality rates of 0 percent, 16.1 percent
and 35.5 percent on 48 hours, 30 days and one-year follow-up,
respectively. The survival rate was the same for the patients
who underwent surgery as for controls who did not have surgery.
Several risk factors for perioperative mortality have been
identified. Emergency procedures are associated with a higher
mortality rate regardless of the age group. In 795 patients
above 90 years of age, the 48-hour mortality rate for patients
undergoing emergency surgery was 7.8 percent versus .6 percent
in those who were age matched but undergoing elective surgery.
2 The location of the surgical
site also has an important impact on mortality rate. Procedures
involving the thorax or abdomen have been shown by multiple
studies to have higher complication and mortality rates. 3
In addition, coexisting diseases have been found to be important
risk predictors of perioperative mortality. Current data support
the view that the effects from coexisting disease outweigh the
effects of age alone on anesthetic outcome. When age and severity
of illness are compared, the number of coexisting diseases is
more significant. Recently, several studies have identified
albumin level to be a good predictor of postoperative mortality.
4 Albumin, a marker of nutritional
status, may serve as a surrogate marker for the preoperative
health status of the surgical geriatric patient.
Since emergency procedures increase perioperative risk, early
surgical treatment should be considered whenever possible. Delaying
surgery just because of the patient's age is not supported by
the literature. Every effort should be made to perform a thorough
preoperative evaluation, including nutritional assessment, and
to optimize the status of the patient's chronic medical diseases
as much as possible before surgery. That assessment and care
should continue postoperatively, especially after emergency
surgery where there may be insufficient time for preoperative
improvement.
Cardiovascular Morbidities
The elderly are more prone to develop cardiovascular complications.
A study by Pedersen et al. in 1990 examined patients over 80
years of age who were undergoing anesthesia.
5 He reported a 16.7 percent cardiovascular complication
rate compared to 2.6 percent in those less than 50 years of
age. A high rate of cardiovascular complications (40 percent)
was found in patients with preoperative heart disease, especially
those with clinical signs of congestive heart failure, prior
history of ischemic heart disease or previous myocardial infarction.
Our recent study also found a similar cardiovascular complication
rate of 12.5 percent in 367 patients over 80 years of age undergoing
noncardiac surgery. 6 Our results,
along with those from previous studies, suggest that the type
of anesthesia does not appear to influence perioperative cardiovascular
morbidity. Rather, hemodynamic control may be more important.
While some of the risks associated with adverse cardiovascular
outcomes have been identified, randomized studies are lacking
in determining whether modifying risks may improve outcomes.
Some risk factors such as a history of congestive heart failure
may be difficult to diagnose preoperatively. In fact, one-third
of geriatric patients with heart failure may have diastolic
dysfunction despite having normal systolic function. In the
absence of specialized tests for estimating preoperative heart
function, the goal should be to optimize symptomatic complaints
as much as possible prior to surgery.
Pulmonary Morbidities
In a study of 7,306 anesthetics administered to patients over
80 years of age by Pedersen et al., 10.2 percent developed pulmonary
complications, similar to a rate of 7 percent found in our recent
study of patients 80 years or older. 5
6 In our study, we further demonstrated
that a prior history of congestive heart failure and prior neurologic
history increased the odds of an adverse postoperative pulmonary
event by multivariate analysis.
Preoperative optimization of respiratory function is important
in decreasing adverse pulmonary events. Cessation of smoking
is associated with better outcomes even immediately prior to
surgery since carbon monoxide levels have been shown to decrease
soon after cessation. Good exercise capacity may also impact
perioperative outcome. In a study investigating patients scheduled
for abdominal and noncardiac thoracic surgery, patients who
were unable to raise their heart rate above 99 beats per minute
or perform two minutes of supine bicycle exercise had a higher
cardiopulmonary complication rate (42 percent versus 9.3 percent).
7
Neurologic Morbidities
There is a wide variation in the reported incidence of postoperative
cognitive deficit (POCD) in the literature. One of the largest
studies of elderly surgical patients was conducted by Moller
et al. 8 The authors found that
POCD was present in 25.8 percent of patients one week after
surgery and in 9.9 percent of patients three months after surgery.
This was compared to a control group of hospitalized patients
not undergoing surgery who had a POCD rate of 3.4 percent one
week after hospitalization and 2.8 percent three months after
hospitalization. Increasing age, duration of anesthesia, lack
of education, a second operation, postoperative infections and
respiratory complications were identified as risk factors for
early cognitive dysfunction.
Several studies have looked at general versus regional anesthesia,
since general anesthesia may lead to changes in cerebral blood
flow and cerebral metabolic oxygen consumption. The evidence
to date suggests that although cognitive deficits may occur
postoperatively, no particular anesthetic technique appears
to be implicated. 9 Furthermore,
a history of preoperative neurologic disease has been demonstrated
by our study to also increase the rate of POCD. 6
Until more definitive clinical studies become available, minimizing
the number of medications used, avoiding hypoxemia and hypercarbia,
providing adequate postoperative pain control and involvement
of geriatricians in postoperative care appear to be the best
approach in minimizing the occurrence of POCD in the geriatric
surgical patient.
Conclusion
Surgery in the geriatric population is not without risk, but
the mortality rate has markedly decreased. Chronological age
is much less important as an independent risk factor. A more
important predictor is the presence of coexisting disease. Although
prospective trials involving risk modification are lacking,
medical optimization, adequate planning preoperatively, including
scheduling surgery electively as opposed to emergently, and
improving nutritional status may be helpful. Anesthetic technique
is probably not as important as meticulous control of hemodynamics
perioperatively. Opportunity to improve perioperative outcomes
in the elderly will be possible when risk factors for these
adverse events can be modified and outcomes evaluated in prospective
trials.
References:
1. Warner MA, Saletel RA, Schroeder DR, et
al. Outcomes of anesthesia and surgery in people 100 years of
age and older. J Am Geriatr Soc. 1998; 46:988-993.
2. Hosking MP, Warner MA, Lobdell CM, et al.
Outcomes of surgery in patients 90 years of age and older. JAMA.
1989; 261:1909-1915.
3. Adkins RB, Jr, Scott HW, Jr. Surgical procedures
in patients aged 90 years and older. South Med J. 1984;
77:1357-1364.
4. Gibbs J, Cull W, Henderson W, et al. Preoperative
serum albumin level as a predictor of operative mortality and
morbidity: Results from the National VA Surgical Risk Study.
Arch Surg. 1999; 134:36-42.
5. Pedersen T, Eliasen K, Henriksen E. A
prospective study of risk factors and cardiopulmonary complications
associated with anaesthesia and surgery: Risk indicators of
cardiopulmonary morbidity. Acta Anaesthesiol Scand. 1990;34:144-55.
6. Liu LL, Leung JM. Predicting adverse postoperative
outcomes in patients aged 80 years or older. J Am Geriatr
Soc. 2000; 48:405-412.
7. Gerson MC, Hurst JM, Hertzberg VS, et al.
Prediction of cardiac and pulmonary complications related to
elective abdominal and noncardiac thoracic surgery in geriatric
patients. Am J Med. 1990; 88:101-107.
8. Moller J, Cluitmans P, Rasmussen L, et
al. Long-term postoperative cognitive dysfunction in the elderly:
ISPPOCD1 study. Lancet. 1998; 351:857-861.
9. Williams-Russo P, Sharrock NE, Mattis S,
et al. Cognitive effects after epidural vs general anesthesia
in older adults. A randomized trial. JAMA. 1995; 274:44-50.