Decreasing Postoperative Delirium in Bangkok

August 2, 2019
by Sandra Gordon for ASA

Varinee Lekprasert, M.D., M.S., a neuroanesthesiologist with Ramathibodi Hospital in Bangkok, discusses two postoperative delirium (POD) cases that changed her perioperative practices to enhance recovery in older patients.

Ten years ago, Dr. Lekprasert was aware of POD. “But I never thought it had such an impact on patients and their families,” she says. Then, she met the family members of two new patients preoperatively. “These cases were my wake-up call.”

Adding BIS Monitoring for Patient-Focused Recovery
The first patient, a 75-year-old male, was scheduled to have surgery for colon cancer. The week before, the patient’s daughter, a psychiatrist at a renowned teaching hospital in Bangkok, called Lekprasert directly. “My dad is the CEO of a big company,” the daughter said. “He used to have a high level of mental functioning. Now, he can’t drive or go back to work after the surgical repair of an abdominal aortic aneurysm. I don’t want to have the same problem happen again.”

After contacting the physician who had taken care of the patient in the ICU, Lekprasert learned the patient had had postoperative delirium for about a week. He had required a psychiatric consultation and lots of medication, too. The patient had gradually recovered. Still, three months later, with his colon cancer surgery now scheduled, he had yet to return to work.

To reduce the patient’s perioperative risk of POD this time around, Lekprasert used a bispectral index (BIS) monitor to assess the depth of anesthesia. “I kept his number between 50 and 60, trying not to keep him too deep,” says. “My goal was to have the patient maintain a high level of mental functioning.”

At Ramathibodi Hospital, a government-run institution, patients pay extra for BIS monitoring, so it’s only used in isolated circumstances, such as when inducing barbiturate coma in neurological cases. In this situation, however, adding the extra monitor paid off.

After cancer surgery with BIS monitoring, the patient—the psychiatrist daughter’s CEO father—woke up in the same cognitive state he demonstrated preoperatively. He didn’t experience delirium in the ICU either. After being intubated and transferred to the ICU, the patient stayed only one night. He was moved to the floor the next day. The patient’s daughter was so satisfied with her father’s post-surgical recovery that she flew to a business meeting the next day.

Tailoring Blood Pressure to Individual Circumstances
The second case involved a 71-year-old woman who had undergone kyphoplasty the year before. For a subsequent kyphoplasty, the patient’s husband was worried. “My wife was forgetful for a few months after the surgery,” the husband said, in a preoperative consultation with Lekprasert. “Her memory is still not as good as before. She used to speak French and Cambodian. After the surgery, she can no longer speak French.”

The husband also divulged another notable detail: “The doctor told me her brain had low oxygen during the surgery.” In checking the patient’s medical record, her systolic blood pressure was around 100–120 during surgery.

Consequently, during the second kyphoplasty, Lekprasert monitored the patient’s blood oxygen saturation. “If you look at the pulse oxygen meter, it’s always 100 percent all the time. But this time, I saw the transient decrease of regional cerebral oxygen saturation, about 20 percent lower than baseline,” she said. Lekprasert noted that patient’s baseline rSO2 R/L was 52/58. During bone cement injection, it changed from 69/70 to 53/49.

Before induction for this second surgery, the patient’s blood pressure was 130/90. “I noticed after intubation that her blood pressure went up to 140/90, and rSO2 increased about 20 percent. I decided to keep her blood pressure at 130 to 160,” Lekprasert says. She had checked the patient’s surgical records and noted that the patient’s previous anesthesiologist had kept her blood pressure between 100 and 120, which wasn’t low, but perhaps too low for the patient’s hypertensive condition.

The next day, Lekprasert visited the patient accompanied by her sister in her hospital room. “Her sister hugged and thanked me, and said, ‘My sister is the same person,’” Lekprasert says.

Focusing Beyond Traditional Performance Indicators
“After my experience with these two patients, I always tell my residents not to keep blood pressure too low. One size doesn’t fit all, especially in the elderly with a history of hypertension,” Lekprasert says. “They probably need a little higher blood pressure than normal to maintain proper blood pressure during surgery.”
Note: Best Practices for Postoperative Brain Health: Recommendations From the Fifth International Perioperative Neurotoxicity Working Group supports avoiding intraoperative hypotension using parameters relative to each person’s baseline blood pressure, with a goal of maintaining cerebral perfusion.

Although BIS monitoring remains controversial, Best Practices Recommendations acknowledges that the BIS monitor uses a proprietary algorithm and has never been specifically validated for use in older adults; Lekprasert recommends it, especially in the elderly and in patients with a history of postoperative delirium.

“Just changing a few things in surgery, such as adding a BIS monitor and knowing the right blood pressure for each individual, can make big difference,” Lekprasert says. “It’s not difficult but it does require paying attention to each patient.”


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