|
February
2000
Randomized Trial of Hypotensive Epidural Anesthesia in
Older Adults.
Williams-Russo P, Sharrock NE, Mattis S, Liguori GA, Mancuso C, Peterson
MG, Hollenberg J, Ranawat C, Salvati E, Sculco T.
Anesthesiology. 1999; 91:926-935.
Commentary by Richard
W. Rosenquist, M.D.
Return to the Current Literature
Review Front Page
[ see abstract below ]
Deliberate
hypotension has been promoted as a means of providing dry surgical fields
or decreasing blood loss during certain procedures. A wide variety of techniques
have been developed to achieve deliberate hypotension. These techniques have
been used in healthy young patients and in surgical procedures that cannot
be performed under normotensive conditions. It has been widely held that elderly
patients or patients with pre-existing cardiovascular disease or renal dysfunction
may be at significant risk for ischemic injury in nonsurgical regions, such
as the kidney, brain or heart. As a result, these hypotensive techniques have
been largely avoided in this setting. This randomized controlled clinical
trial challenges conventional wisdom and suggests that hypotensive epidural
anesthesia can be safely used in the setting of total hip replacement surgery
in older adults. This group of patients does not include those with occlusive
carotid disease (greater than 70% occlusion) or hemodynamically significant
aortic valve or mitral valve stenosis who were excluded from participating
in their study.
A number of studies have documented intraoperative blood
loss during uncomplicated total hip replacement in normotensive patients
ranging from 500 to 1800 ml. Even in the higher mean arterial blood pressure
group in this study, the blood loss was reduced to an average of 212 ml.
The reduced bleeding and cleaner surgical field may provide benefits beyond
the decreased blood loss. The drier surgical field may reduce the amount
of blood at the cement-bone interface, improving the quality of fixation
of the prosthetic to the bone and potentially may help to decrease aseptic
loosening of the prosthetic to the bone in the future. The authors are
very careful to warn the reader that this study demonstrated the safety
of hypotensive epidural anesthesia in older adults with comorbid diseases
using their specific protocol. This includes the use of continuous hemodynamic
monitoring, supplemental oxygen and the avoidance of hypovolemia. They
also note that the results are not necessarily applicable to other techniques
of hypotensive anesthesia. These authors have provided a valuable service
in challenging the accepted dogma that hypotensive epidural anesthesia
or hypotensive anesthesia for total hip replacement should be avoided
in patients with comorbid illnesses. Using the protocol described, there
was no evidence of early or long-term cognitive, cardiac or renal complications
in elderly patients undergoing total hip replacement with hypotensive
epidural anesthesia using mean arterial pressures of between 45-55 mmHg
and 55-70 mmHg. These techniques require vigilance on the part of the
anesthesiologist, but may offer a significant benefit with respect to
the performance of total hip replacement surgery and should be considered
by practitioners who perform numerous total hip replacement surgeries.
ABSTRACT
Randomized Trial
of Hypotensive Epidural Anesthesia in Older Adults.
AUTHORS: Williams-Russo P, Sharrock NE, Mattis S, Liguori GA,
Mancuso C, Peterson MG, Hollenberg J, Ranawat C, Salvati E, Sculco T.
SOURCE: Anesthesiology. 1999; 91:926-935.
ABSTRACT:
Objective: To evaluate the incidence of postoperative cognitive cardiac
and renal complications after deliberate hypotensive anesthesia in elderly
patients undergoing total hip replacement surgery.
Design: Randomized controlled clinical trial.
Participants: A total of 235 older adults with comorbid medical illnesses
undergoing elective primary total hip replacement with epidural anesthesia.
Methods: Patients were randomly assigned to one of two levels of
intraoperative mean arterial blood pressure management, either to a markedly
hypotensive mean arterial blood pressure range of 45-55 mmHg or to a less
hypotensive range of 55-70 mmHg.
Outcome Measurers: Cognitive outcome was assessed by within-patient
change on 10 neuropsychologic tests assessing memory, psychomotor and language
skills from before surgery to one week and four months after surgery. Standardized
surveillance was performed for cardiovascular and renal outcomes, delirium,
thromboembolism, and blood loss and replacement.
Results: The two groups were similar at baseline with respect to
age, sex, comorbid conditions and cognitive function. Following operation,
no significant differences in the incidence of early or long-term cognitive
function were observed between the two blood pressure management groups.
There were no significant differences in the rates of other adverse consequences,
including cardiac, renal and thromboembolic complications. In addition,
no differences occurred in the duration of surgery, intraoperative estimated
blood loss or transfusion rates.
Conclusions: Elderly patients can safely receive controlled hypotensive
epidural anesthesia for total hip replacement surgery using the protocol
described in the article. (Bupivacaine [20-25 ml] 0.75% was administered
via epidural catheter using standardized techniques. Adjunctive medications
for sedation included midazolam, fentanyl and thiopental sodium. All patients
received a low-dose intravenous epinephrine infusion at an infusion range
of 1-5 ug/min to maintain circulatory stability) There was no evidence for
greater risks or early benefits with the use of the more markedly hypotensive
range in this study.
|
