Hip Resurfacing Under Scrutiny

Hip resurfacing was once viewed as a preferable alternative to total hip arthroplasty, preserving more of the patient's femur, providing greater mobility and creating less risk of dislocation. But the procedure has come under increasing scrutiny, and a research group has even withdrawn its support for the surgery's outcomes, reports the Oct. 20 edition of the New York Times.

The California Technology Assessment Forum has recently concluded that, in its view, the available data on resurfacing's outcomes (based on British and Australian databases) as well as the lack of clinical studies directly comparing them to those of traditional hip replacement doesn't provide sufficient evidence for the procedure's safety and effectiveness. (The CTAF is funded by the Blue Shield of California Foundation.)

At issue is the metal-on-metal hardware used in resurfacing, which has also been a source of recent controversy for replacement procedures. According to the CTAF, the British and Australian data have shown the metal implants to fail prematurely. What's more, the implants shed metallic debris with wear and tear, and research on the long-term effects of this debris in joints is sparse.

While the Times article notes that the procedure is seeing less use in older male patients and in female patients, it also quotes critics of the CTAF's reversal who point out that it is still ideal for younger and middle-aged men.

David Bernard

Researchers Identify 3 Factors That Influence Anesthetized Patients' Mortality

Low values in BIS, blood pressure and anesthetic concentration could increase risk of death, new research suggests.

Duke University researchers found that patients who are sensitive to anesthesia, as represented a by a triple combination of low bispectral index, mean arterial pressure and anesthetic concentration, have a 2.5 times increased risk for post-operative one-year mortality compared to patients whose values are all normal. Researchers refer to this as a "triple low."

"The take-home message is that physicians who learn about this triple-low set of factors should be alert to the needs of such a patient after surgery and watch for potential problems or avoid the triple-low combination in the first place," says study co-author Tong J. Gan, MD, a professor of anesthesiology at Duke. The study was presented at the American Society of Anesthesiologists' annual meeting in Chicago last week.

The researchers' study was inspired by smaller studies that indicated these values had predictive power. They wanted to examine data from a much larger sample, studying the cases of nearly 20,000 patients who underwent non-heart-disease-related procedures. Even after adjusting for patient age and risk profile, the findings held up. Risk of death in the first post-op year was even significant among patients exhibiting a "double low" in MAC and BIS values.

Mark McGraw

Obese Pediatric Patients Require Less Propofol

Obese pediatric patients require lower induction doses of propofol than their non-obese peers when dosing levels are based on actual body weight, according to a study presented last week at the annual meeting of the American Society of Anesthesiologists.

The average effective dose for obese and non-obese children differed by 1.19mg/kg (1.99mg/kg vs. 3.18mg/kg, respectively), meaning obese children require about 50% less propofol at induction.

"Propofol decreases systemic vascular resistance, and doses larger than that required for loss of consciousness may result in moderate to severe hypotension," the study notes. "Administration of effective doses of propofol based on the actual body weight allows for a more precise dosing for the desired outcome."

Many anesthesia providers assume lean body mass - mass of the body less the fat - should be used to calculate effective doses, explains John Dombrowski, MD, director of the Washington Pain Center in Washington, DC. Olutoyin A. Olutoye, MD, a staff anesthesiologist at Texas Children's Hospital in Houston and the study's lead researcher, points out however that 75% of the excess weight in obese children is made up of fat tissue, which alters drug distribution.

To determine propofol's effective dose in obese patients - measured by loss of lash reflex at 20 seconds after administration in 95% of the patients involved in the study - Dr. Olutoye and colleagues assessed 40 obese and 40 non-obese healthy children aged 3 to 17 years of age. Each child received a propofol IV dose ranging from 1.0mg/kg to 4.25mg/kg (propofol's recommended dose is between 2.5mg/kg and 3.5mg/kg) based on the response of the previous patient. For example, if lash reflex persisted in a patient past 20 seconds, the next patient would receive a 0.25 mg/kg higher dose. That gradual dosing increase continued until the desired effect was achieved.

In another study presented at ASA, Olubukola O. Nafiu, MD, FRCA, assistant professor of anesthesiology at the University of Michigan Health System in Ann Arbor, says asthmatic children are twice as likely as non-obese children to suffer at least 1 respiratory complication during or following surgery.

Dr. Nafiu says his findings suggest obese asthmatic pediatric patients undergoing anesthesia should receive additional care and evaluation during their perioperative care.

Daniel Cook

InstaPoll: Is Your Staff Getting a Raise?

Staff raises are a touchy subject, especially in this tough economy. Tell us how you're handling salary increases in this week's InstaPoll.

Seven out of 10 of the 106 facility managers who took last week's poll rate their staffs' between-patient hand hygiene compliance as either pretty good (47%) or excellent (24%). The full results:

  • Excellent : 24%

  • Pretty good: 47%

  • So-so: 12%

  • Needs improving: 9%

  • Poor: 8%

    Dan O'Connor

  • News & Notes
  • Anesthetics have no post-op delirium link Inhaled anesthetics such as isoflurane do not increase the incidence of post-operative delirium, which can affect recovery, according to a study presented at the American Society of Anesthesiologists' annual meeting last week. In the study, patients were given pre-surgical tests to determine brain function and depression levels. During surgery, the patients received opioids with either an inhaled anesthetic or intravenous anesthetic. Post-operative delirium occurred in 12.6 percent of the patients receiving inhaled anesthesia, and in 13.6 percent of patients receiving intravenous anesthesia.

  • "Man up" nurse sued Minneapolis-area surgery patient Larry King is suing the nurse who told him to "man up" after she stole the pain medications he was to receive prior to a kidney stone procedure. Sarah Casareto, RN, received 3 years' probation for her actions as part of a September plea agreement. "Justice was not served," Mr. King's attorney told local news reporters.

  • Implant makers' payments to ortho docs down A study appearing in the Oct. 24 issue of the Archives of Internal Medicine points out that the makers of hip and knee implants have made fewer payments of smaller amounts to orthopedic surgeons since the U.S. Department of Justice's 2005 investigation of the practice and 2007 settlement with five leading manufacturers required the disclosure of such consulting and research funding. A commentary to the article, however, remarks that the policing of financial conflicts of interest between physicians and vendors still has a long way to go.
  •