CLOSE WATCH Anesthesia providers must micromanage the small details of a patient's condition.

The 3 golden rules of patient monitoring? Don't forget the basics. Too much monitoring is better than too little. And expect the unexpected — be prepared to go to a level of monitoring that you didn't anticipate when the case started. So says Carl R. Noback, MD, a board-certified anesthesiologist with a subspecialty in pain management and the medical director for Innovative Practice Strategies in Sarasota, Fla. Read on as Dr. Noback shares the principles of good intraoperative monitoring and how it can be used to speed patient recoveries.

Better use of the basics
Standards of the American Society of Anesthesiolo-gists dictate that monitoring for every procedure performed with general anesthesia should include blood pressure, EKG, end tidal CO2 (capnography), exhaled gas analysis, body temperature and pulse oximetry. Pulse ox monitors delivery and global function of the respiratory system and, coupled with BP and EKG, establishes a solid set of vital signs to monitor.

Bispectral index (BIS) monitoring of depth of consciousness is optional, and it has its proponents, but it comes with a non-reimbursable per-utilization cost that can top $25 per procedure, says Dr. Noback, which is a detractor. In his experience, based on a BIS trial he was part of (which was discontinued in the pilot phase), the readings can be discordant with the patient's state.

Rather, he believes, the tools you already have to judge presumed anesthetic depth are adequate. Monitoring the concentration of anesthetic in exhaled gases in particular can ensure quicker wake-up in post-op. To do this, says Dr. Noback, the provider should continue to ventilate the patient (either artificially or manually) instead of continuing the anesthetic while the dressings are being applied, to bring the exhaled anesthetic down to near zero. The patient will have already begun the process of "blowing off" the anesthesia and will wake faster.

The biggest changes in monitoring standards have been the inclusions of capnography and further details on temperature monitoring, says Dr. Noback, driven by changes in practice at the front lines. "The inclusion of capnography followed the availability of early mass spectrometers and was concomitant with the rise of infrared CO2 analyzers," he says.

Capnography has 2 key uses intraoperatively. First, through identification of expired CO2, it ensures the endo tube has been properly placed — that esophageal intubation (which can lead to adverse effects) hasn't occurred. Second, it prevents hyperventilation (which can change cerebral blood flow and reduce anesthetic flow) or hypercapnia (which is a vasodilator and can create significant problems with anesthesia management and recovery). End tidal monitoring lets the anesthesia provider play the role of Goldilocks, getting everything "just right" by maintaining a near-normal CO2 level, which indicates accuracy of respiration and avoids over- or under-ventilation.

Temperature monitoring now stresses the importance of maintaining normothermia as nearly as possible. Not just to track the temperature, but so the OR staff can do something about it by actively warming patients in whom core temperatures have dipped. Today's warming devices try to cover as much of the body as possible to transfer maximum heat, and subsequently get patients to discharge criteria faster in recovery (see "Warming to Faster Patient Discharges").

WAVE OF THE FUTURE
Will Monitoring Become More Invasive?

BEYOND THE BASICS Tracking standard vital signs may not be adequate as more complex cases move to the outpatient arena.

Once you move beyond EKG, blood pressure, pulse ox, and the like, monitors abruptly transition from topical to invasive. Currently, the market is giving rise to devices that provide transcutaneous versions of formerly invasive monitoring, such as blood pH and hemoglobin analysis to assess cardiac output, says Carl R. Noback, MD, a board-certified anesthesiologist with a subspecialty in pain management and the medical director for Innovative Practice Strategies in Sarasota, Fla.

"Generally speaking, I think we're going to see more of a need to use some of these higher-level noninvasive monitors as more of the bigger cases —multi-level spinal fusions, joint replacements — move to the outpatient setting," he says.

Dr. Noback also sees a trend toward the use of invasive monitoring, such as central venous pressure monitoring, in the outpatient setting. "A lot of managers and administrators might say, 'I don't want to go to that expense. We operate only on ASA 1 or 2 patients, maybe the occasional ASA 3 in this facility,'" he says. "But ASA physical status is a pre-procedure assessment of the patient and doesn't take into account physiologic changes that happen during procedures."

For example, if a surgeon nicks an epidural vein, a patient's ASA status won't have much bearing; rather, the right monitor could spot blood loss more quickly. As more complex, traditionally inpatient procedures shift to outpatient facilities, and anesthetic monitoring practice changes accordingly, Dr. Noback believes more recommendations and regulations will call for equivalent monitoring to prevent and manage physiologic disruption caused by unintended events during procedures.

— Stephanie Wasek

Avoiding trouble
If a muscle relaxant is used, anesthesia providers should employ neuromuscular monitoring to ensure adequate oxygen delivery and ventilation, says Dr. Noback. It can be one of the first intraoperative indicators that a patient is having respiratory difficulties and, post-operatively, lets you assess residual muscle relaxant effect.

"As the patient begins to wake, metabolism and blood flow increase again. This reperfusion of the blood vessels can actually wash any residual anesthetic agents into the system, renarcotizing the patient and potentially leading to respiratory distress," he says. "Neuromuscular monitoring is especially crucial in overweight, obese and sleep apneatic patients, who are more vulnerable to such distress in the first place."

It's also important to continuously monitor the blood sugar of diabetic patients. Stress on the body and a steroid in the IV can cause blood sugar spikes, which can be handled with short-acting insulin until the stress can be resolved by pain medication, and the patient can get back on a normal insulin and eating schedule. There are now devices that transcutaneously assess blood sugar, which makes maintaining normal levels easier, says Dr. Noback.

LEGAL LIABILITY
When Vital Signs Are Ignored

Intraoperative monitoring is a staple of surgery, so it's easy to forget just how crucial blood pressure, EKG and pulse oximetry really are. But a recent court case provides a stark reminder of the dangers of forgetting the vital importance of vitals.

In 2008, a patient's blood or oxygen supply was interrupted for several minutes, in part due to the anesthesiologist's failure to monitor pulse ox. The patient ended up comatose and paralyzed. In December 2012, the anesthesiologist was fined and his medical license suspended for at least 6 months, according to Florida Department of Health documents related to the disciplinary actions. And in June, he was found 23% liable in the resulting medical malpractice case (the surgeon took the rest of the blame), which came with a $38.5 million award to the patient.

— Stephanie Wasek

Rules to monitor by
When Dr. Noback worked at Harbor-UCLA Medical Center, a sign read: "The 7 rules of anesthesia are vigilance, vigilance, vigilance, vigilance, vigilance, vigilance, vigilance." It's true: Micromanagement of small details has increased anesthesia safety remarkably. "When I started medical school, anesthesia-related deaths were 1 in 3,000 to 5,000 procedures," says Dr. Noback. "The latest data show the anesthesia complication rate — complications, not deaths — to be 1 in 400,000 cases. That's all due to monitoring changes that have let anesthesia providers be more vigilant about micromanaging the surgical environment."