ISSUE: DECEMBER 2006 | VOLUME: 32:12 printer friendly | email this article | more clinical anesthesiology
OR Extubation Avoids Costs, Complications
Linda Pembrook
SAN DIEGO—Extubating patients in the operating room immediately after major cardiac surgery can be achieved safely and may hasten rehabilitation and reduce healthcare costs, Canadian researchers have found.
“With newer anesthetic techniques in cardiac surgery, especially the use of shorter acting drugs, a shift to a more balanced anesthesia and the extensive use of regional techniques, we believe routine immediate extubation should be possible after cardiac surgery without increasing cardiorespiratory morbidity and mortality,” said Thomas Hemmerling, MD, an anesthesiologist at Montreal General Hospital in Quebec and the study’s lead author. Dr. Hemmerling presented the findings at the 2006 annual meeting of the Society of Cardiovascular Anesthesiologists.
“Almost 80% of [cardiac surgery] patients could be extubated in the operating room,” said study co-author David Bracco, MD, Associate Professor of Anesthesia at McGill University Health Centre. “We do it routinely in thoracic, orthopedic and other types of surgery.”
Cardiac surgery has lagged these other procedures because of a historical reliance on opioids such as fentanyl, causing respiratory suppression that demanded patients remain intubated for as long as 24 hours following surgery.
High thoracic epidural analgesia is advantageous as adjunctive anesthesia and analgesia, providing superior pain management, reducing opioid requirements and improving both pulmonary function and myocardial protection.
The Canadian study—part of a broader look at ways to make cardiac surgery more efficient—included 588 patients who underwent off-pump coronary artery bypass graft (CABG) surgery and 58 who underwent on-pump CABG. Another 134 had aortic-valve replacements that were either simple or combined with CABG, and 39 had mitral-valve replacements or reconstructions. The average duration of surgery was 127 minutes, and ischemic time during aortic cross-clamp was 59 minutes.
The mean age of patients was 64 years and mean weight was 77 kg. Eight percent had an ejection fraction of less than 40%, 61% had high blood pressure, 13% had chronic obstructive pulmonary disease and 26% had diabetes.
Patients underwent three regimens for analgesia. One group received high T2/T3 thoracic epidural anesthesia (TEA) installed preoperatively and removed after 72 hours; a second group received fentanyl during surgery followed by patient-controlled analgesia (PCA) with morphine; and a third group underwent bilateral paravertebral blocks plus fentanyl followed by PCA-administered morphine. Anesthesia was induced using standard protocols with fentanyl and propofol, and maintained using sevoflurane titrated to a level of 40 to 50 on the bispectral index monitor (BIS, Aspect Medical Systems).
“All patients were successfully extubated immediately after cardiac surgery in the OR within an average of 15 minutes, and there were no differences between groups,” Dr. Hemmerling said. “Patients were sent to the postoperative anesthesia care unit [PACU] for between two and four hours for stabilization.”
Postoperative pain scores were significantly lower for patients who received TEA than for those in the other two groups, Dr. Hemmerling said (Figure, page 54). No complications related to epidural catheter placement and no permanent neurological complications were observed, according to the researchers. Only four patients (0.5%) needed reintubation, one because of respiratory failure that occurred within 60 minutes of extubation, one secondary to myocardial infarction (MI) and respiratory depression, one as a result of residual muscle relaxant and one attributable to uncontrollable agitation.
Postoperative mortality was 1.2%. MI occurred in 2.8% of patients and low output syndrome in 2.4%. Of the patients in the cohort, 13.2% needed blood transfusion and 18.9% developed atrial fibrillation.
“In order for immediate extubation in cardiac surgery to work, it is necessary to have the proper infrastructure,” Dr. Hemmerling said. “This may not be possible in hospitals where intubation time is controlled by the nurses in the ICU [intensive care unit].”
In a follow-up study, reported in October at the Canadian Cardiovascular Congress, Dr. Hemmerling’s group estimated that rapid extubation could save nearly $1,500 per patient in lower ventilation costs and generate additional savings, which they did not calculate, by shifting more patients from the ICU into the PACU and limiting ICU stays.
In addition, the Montreal team has seen fewer cases of pneumonia, catheter-related blood stream infections and positive blood cultures, Dr. Bracco said.
Daniel Bainbridge, MD, a cardiac anesthesiologist at the University of Western Ontario in London, said that at most institutions in the United States and Canada, cardiac surgery patients are extubated in the OR only in off-pump cases. In most on-pump CABGs, the patient is extubated in the ICU after four to six hours, he said.
“A few studies have shown that there is not much benefit in terms of either outcome or costs to doing immediate extubation,” Dr. Bainbridge told Anesthesiology News. “The time you save in the ICU you lose in turnover in the OR. Only randomized controlled studies will show whether there is indeed a benefit to immediate extubation.”
Most anesthesiologists are concerned about the potential for epidural hematoma with a thoracic epidural, Dr. Bainbridge added. “Again, well-constructed randomized trials are needed to determine the benefit of thoracic epidurals in patients who would be candidates for regional anesthesia.”
An interesting trend in cardiac surgery is that patients now tend to be older and sicker and might benefit in the long run from an epidural, Dr. Bainbridge noted. Whether it is possible to bypass the ICU and shorten their stay in the hospital is unclear. Even with immediate extubation, a patient may need monitoring because of postoperative delirium, stroke, renal dysfunction or other problems. Savings in nursing care are therefore unlikely.
Based on poster presentations at the 2006 annual meeting of the Society of Cardiovascular Anesthesiologists and the 2006 Canadian Cardiovascular Congress, and interviews with Thomas Hemmerling, MD, David Bracco, MD, and Daniel Bainbridge, MD.