Weight loss before gastric bypass surgery

AORN Journal,  Feb, 2008  by George Allen

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Archives of Surgery

October 2007

Approximately 5% of the US population meets the criteria for morbid obesity: a body mass index (BMI) greater that 40. Body mass index is calculated as weight in kilograms divided by height in meters squared. Bariatric surgery thus far is the only effective long-term treatment for morbidly obese patients with obesity-related comorbidities. Selected studies have shown that high-risk patients face a much higher surgical risk than the morbidity and mortality rates described in recent peer-reviewed literature, and the optimal preparation for high-risk individuals with significant comorbid medical conditions continues to be controversial. Modalities that might decrease risk include preoperative weight loss, intra-gastric balloon placement, and staging procedures. The objective of this prospective, longitudinal study was to determine the potential effect of modest preoperative weight loss on hospital length of stay and overall weight loss after Roux-en-Y gastric bypass.

Between May 31, 2002, and February 24, 2006, all patients undergoing open or laparoscopic Roux-en-Y gastric bypass for morbid obesity or its comorbid medical problems at a medical center in Danville, Pennsylvania, were entered into the study. Patients undergoing laparoscopic adjustable gastric banding were excluded because of the significant difference in surgical risk and length of stay as well as rate of postoperative weight loss.

Since 2001, all patients undergoing bariatric surgery at the medical center have been required to participate in a standardized, multi-disciplinary preoperative program that encompasses medical, psychological, nutritional, and surgical interventions and education. Patients must be tobacco-free for at least six months before the procedure. They are required to attend two educational sessions, read a book about bariatric surgery, complete 10 behavior modules, attend two support group meetings, and attempt to achieve a 10% loss of excess body weight before surgery.

To determine weight change before bariatric surgery, BMIs from the first visit to the weight management clinic were compared with BMIs at the time of surgery. Values were compared with the patients' ideal body weight (ie, a BMI of 25) to calculate the percentage of excess weight loss before surgery. The participants were placed in one of five groups:

* group 1--more than 5% excess body weight gain,

* group 2--0% to 5% excess body weight gain,

* group 3--0% to 5% excess body weight loss,

* group 4--5% to 10% excess body weight loss, and

* group 5--more than 10% excess body weight loss.

Common statistical techniques including the chi-square test, Fisher exact test, analysis of variance, and logistic regression techniques were used to analyze the data.

FINDINGS. A total of 884 patients met the inclusion criteria; 692 (78%) were female and 192 (22%) were male. The mean weight at the time of surgery was 137.7 kg (standard deviation [SD] 23.2) for women and 171.8 kg (SD 31.4) for men. The mean BMI at the time of surgery was 51.3 (SD 8.0). Four hundred twenty-five patients (48%) lost more than 10% of their excess body weight before the surgery. After surgery, this group was significantly more likely to achieve 70% loss of body weight (P < .001). Additionally, patients who lost more than 5% of their excess body weight before surgery were significantly less likely to have a hospital length of stay greater than four days (P = .03).

CLINICAL IMPLICATIONS. The results of this study demonstrated that high-risk, morbidly obese patients who are able to achieve a loss of 5% to 10% of excess body weight before bariatric surgery have a greater likelihood of a shorter length of hospital stay and more rapid postoperative weight loss. Perioperative nurses and managers should encourage administrators and policy makers at their institutions to consider implementing a program to facilitate modest weight loss in patients considering bariatric surgery.

Still CD, Benotti P, Wood GC, et al. Outcomes of preoperative weight loss in high-risk patients undergoing gastric bypass surgery. Arch Surg. 2007;142(10):994-998.

GEORGE ALLEN

PHD, RN, CNOR, CIC

DIRECTOR OF INFECTION CONTROL

DOWNSTATE MEDICAL CENTER

BROOKLYN, NY

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