A 63-year-old woman comes to your outpatient facility for an abdominoplasty and liposuction of her thighs and buttocks. During the five-hour procedure, she receives more than three liters of intravenous fluids, and the surgeon injects three liters of fluid for the ultrasonic-assisted suction lipectomy. When she reaches the post-anesthesia care unit, her temperature is 93'F, she is hypertensive, and her shivering rattles the stretcher rails.

An ominous cardiac arrhythmia is unresponsive to standard therapies. You call her cardiologist. An ambulance transfers the patient to a nearby hospital. During transport, she suffers a cardiac arrest and the team is unable to resuscitate her.

Inconceivable? Not at all. As outpatient surgery centers now admit patients with extremes of age for increasingly complex, lengthy and invasive procedures, the perils of hypothermia jut like an iceberg from the sea. And these icebergs will sink your ship and its captain faster than the Titanic. Patient-hypothermia-prevention device manufacturers know it (see "20 Ways to Warm a Patient" on page 50). One warming-blanket manufacturer pledges to cover its product users for up to $500,000 if you're sued for malpractice associated with hypothermia when properly using one of its products.

It's not just older or sicker patients who are at risk for hypothermia, though. All surgical patients are in peril. Because it's much easier to prevent hypothermia than to treat the effects of it, prevention should be a priority. Yet even in the face of clear clinical evidence that warm is good and cold is bad, staff who are sweltering under gowns, hoods and lights often complain about the heating blankets or other technologies used to keep the patient warm. Warm ORs especially heat up complaints from surgeons and staff. It's understandable. Operating with sweat streaming down your back is an unpleasant experience at best. Fortunately, there are ways to warm your patients without inflaming your staff.

The fourth factor
Defeating hypothermia requires an understanding of the condition: the parameters that define it, the mechanisms of heat loss in the surgical patient that cause it and the risks associated with it.

Every clinician has learned the ABCs of patient care: A for airway, which must be open and patent. B for breathing, C for circulation. But there is a fourth factor for patient survival: D, for degrees.

Generally, a patient is considered hypothermic when his temperature is less than 95' F. To help prevent hypothermia, the Centers for Disease Control (CDC) and major healthcare organizations recommend that operating room temperature be set between 68'F and 73' F.

How to best assess hypothermia can be problematic. Axillary, skin and oral temperatures are considered to be the least reliable. While rectal temps more closely reflect the patient's core temperature, most clinicians (and patients) prefer a tympanic temperature. No matter how it's measured, hypothermia increases the incidence of

• surgical site infections, due to reduced perfusion of O2 in tissue;
• cardiac arrhythmias and adverse myocardial events, which are resistant to treatment;
• prolonged length of stay;
• coagulopathy and impaired platelet function;
• shivering, discomfort and lowered patient satisfaction;
• impaired wound healing; and
• altered metabolism of medications.

As heat is lost in one of four ways, hypothermia must be battled on these fronts:

• Conduction. Loss of heat to a solid, as when a patient loses warmth to a cold OR table.
• Convection. Loss of heat through air or liquid, as when a patient is exposed to cool OR air or cool IV fluids.
• Evaporation. Loss of heat when fluid leaves the body and becomes a vapor, as when a body cavity is open and internal tissue is exposed to cool OR temperatures.
• Radiation. Loss of heat in the form of energy released from the body, a small factor in patient hypothermia.

The war on hypothermia
There are myriad modes to defeat hypothermia. Some patient-warming techniques and tools are complex and tedious but highly effective - albeit costly. Others are cheap and easy, a few simple and succinct. Some are basic good sense that may be overlooked in a busy OR. Here are seven ways to warm patients without inflaming your staff or scorching your bottom line.

1. Preheat the patient in the pre-operative area.
Applying an active warming technique in pre-op for just 30 minutes before surgery has been proven to reduce the average temperature drop commonly seen during surgery. While this pre-warming would most often be accomplished with a forced-air warming blanket, you can also begin warming fluids, or use one of the newer technologies noted below. Heated cotton blankets from a blanket warmer or patient warming gowns are superb patient-comfort measures, but they actually have little heat-loss-prevention effect. To actively preheat the patient, use a warming device designed to reduce or prevent hypothermia.

2. Warm the OR table before the patient settles onto it.
A warm table slows the rate of conductive heat loss, where the patient's body heat is transferred to the colder table and its cushion. A forced-air warmer's hose set to high heat can be snuggled under the table's sheet to warm the table before the patient is transferred to it.

3. Cover the patient's head and feet.
You cover your head in the winter, don't you? It feels like winter in many ORs, so a head cover will help keep the patient warm, because most heat is lost through the head. Covering the head with a foil cap or clear plastic (if the patient is intubated) can significantly reduce heat loss. Socks help negate heat loss too; two pairs layered on help prevent hypothermia.

4. Put a humid-moisture exchanger (HME) in the anesthesia circuit.
Reduce patient heat lost to the cool gases blown into the lungs during general anesthesia with these small, inexpensive (a few dollars) devices. Moisture is retained and, as an added bonus, many HMEs have a bacterial filter, too.

5. Cover up.
Limit the exposure of bare skin during prep, cleanup, and bandaging. If this seems obvious, remember that personnel who aren't cold in the OR and who are accustomed to exposed patients can sometimes overlook just how chilly it is when bare skin is exposed to cold air. Evaporation of prep solutions can expedite loss of heat too. When the surgery is completed, staff should wash, promptly dry, and recover the patient as quickly as possible. Keep OR doors closed to reduce drafts that pull heat (convective heat loss) from the patient.

6. Educate staff about the risks of litigation due to patient hypothermia.
Set up a simple in-service outlining the physiologic alterations that accompany hypothermia. Then review the bad things that happen when good patients get cold: morbidity, mortality and lawsuits. Many may be unaware of the risk of hypothermia or believe it insignificant because they haven't seen a hypothermia-related complication.

7. Try some of the new warming technologies.
If you're only familiar with that large warming unit that rolls around on the floor and connects to a filmy blanket, you're out of the loop. Take a look at cutting edge hypothermia-prevention technology and you'll discover hope for finding a common ground between warm patients and cool staff.

Manufacturers produce compact forced-air heaters that clamp to IV poles or perch on the stretcher rails. Newer forced-air warmers deliver the cozy air at a lower velocity to reduce turbulence, and redesigned blankets have fewer tiny particles that can be puffed out into the surgical suite. Blankets are available in more styles, materials and configurations to meet the needs of different specialties. Some warmers have special HEPA filters to help reduce potential bacteria blown through the blankets and into the OR.

Thermal warming pads (Kimberly-Clark) that adhere to the patient (used during cardiac bypass surgeries) may be a viable alternative in longer ambulatory cases that can involve significant heat loss, such as an abdominoplasty. A product expected to be available this summer (Dynatherm) pending 510(k) approval only covers one hand or foot, leaving the rest of the patient available for surgical care. Another advance comes with (Lexion Medical's Insuflow) the warming, filtering and hydrating of the gas insufflated into the abdomen for laparoscopic surgery, a major source of patient cooling. Finally, if you still can't keep your staff cool and your patients warm, try the cooling vests. It may be the solution when the room should be warm but the staff has to be cool.

Maintaining normothermia
Advances in technology, coupled with simple common sense measures, mean most patients can be normothermic upon arrival in the PACU. That means greater patient satisfaction, fewer complications and lower risk of litigation.