Jay B. Prystowsky

Postoperative hypoxemia in morbidly obese patients with and without obstructive sleep apnea undergoing laparoscopic bariatric surgery.

INTRODUCTION: The increased incidence of morbid obesity has resulted in an increase of bariatric surgical procedures. Obstructive sleep apnea (OSA) is a commonly encountered comorbidity in morbidly obese patients. Sedatives, analgesics, and anesthetics alter airway tone, and airway obstruction and death have been reported in patients with OSA after minimal doses of sedatives and anesthetics, yet there is a lack of consensus regarding the care of these patients. In this study, we sought to determine whether obese patients with polysomnography-confirmed diagnosis of OSA were at significantly greater risk for postoperative hypoxemic episodes in the first 24 h after laparoscopic bariatric surgery than morbidly obese patients without a diagnosis of OSA. METHODS: Adult subjects (Body Mass Index, 35–75 kg/m2) scheduled to undergo laparoscopic bariatric surgery were studied. A finger pulse oximetry probe was placed preoperatively and oxygen saturation (Spo2) was recorded continuously. All subjects underwent preoperative polysomnography testing within 4 wk of surgery. Anesthetic management was standardized, using propofol for induction and desflurane and remifentanil for maintenance of anesthesia. Patient-controlled analgesia programmed to deliver morphine, 1 mg. every 10 minutes, was used for pain management postoperatively. Hypoxemic episodes were scored as Spo2 >4% below the polysomnography study baseline and lasting for more than 10 s. RESULTS: Eight men and 32 women were enrolled and 1 subject had incomplete data. Thirty-one of the 40 subjects had polysomnography-confirmed OSA. Eight subjects used home continuous positive airway pressure devices nightly, and six of these used their device postoperatively. Preoperatively, subjects with OSA had lower nadir Spo2 during the polysomnography study and a larger number had an apnea/hypopnea index >10 episodes per hour compared with the non-OSA group. In the first 24 h postoperatively, there was no difference in the median Spo2 with and without oxygen therapy, between OSA and non-OSA groups.The number of episodes of oxygen desaturation >4% below the polysomnography study baseline value and the mean number of desaturation episodes per hour did not differ between the groups. CONCLUSIONS: In morbidly obese subjects, in the first 24 h after laparoscopic bariatric surgery, OSA does not seem to increase the risk of postoperative hypoxemia. Our data confirm that morbidly obese subjects, with or without OSA, experience frequent oxygen desaturation episodes postoperatively, despite supplemental oxygen therapy suggesting that perioperative management strategies in morbidly obese patients undergoing laparoscopic bariatric surgery should include measures to prevent postoperative hypoxemia.

An outcomes research perspective on medical education: the predominance of trainee assessment and satisfaction

A fundamental premise of medical education is that faculty should educate trainees, that is, students and residents, to provide high quality patient care. Yet, there is little research on the effect of medical education on patient outcomes.

Gangrenous cholecystitis: Analysis of risk factors and experience with laparoscopic cholecystectomy

BACKGROUND Gangrenous cholecystitis occurs in up to 30% of patients admitted with acute cholecystitis. Factors predicting gangrenous disease in patients with acute cholecystitis remain poorly defined, making preoperative diagnosis difficult. Identification of these factors and early diagnosis of gangrenous cholecystitis will indicate more aggressive treatment, earlier operation, and a lower threshold for conversion of laparoscopic to open cholecystectomy. METHODS We reviewed our experience with acute cholecystitis during the 2-year period of 1995 to 1996. Admitting history, physical examination, operative report, laboratory and radiology data, and pathology report were analyzed for each patient. Acute cholecystitis and its gangrenous complication were diagnosed by both gross and microscopic examination. RESULTS One hundred fifty-four patients were admitted to the hospital with acute cholecystitis and underwent cholecystectomy; gallbladder gangrene was found in 27 (18%) of these patients. Four patients with gallbladder gangrene underwent open cholecystectomy and 23 patients underwent laparoscopic cholecystectomy, of which 15 (65%) were completed laparoscopically and 8 (35%) had open conversion as a result of severe inflammation. Risk factors for gallbladder gangrene included male gender, age older than 50 years, history of cardiovascular disease, and leukocytosis greater than 17,000 white blood cells/mL. CONCLUSIONS Older male patients (age older than 50 years) with history of cardiovascular disease, leukocytosis greater than 17,000 white blood cells/mL, and acute cholecystitis have increased risk of gallbladder gangrene and conversion of laparoscopic cholecystectomy to open cholecystectomy. Urgent laparoscopic cholecystectomy with low threshold for conversion to open cholecystectomy should be considered in these patients at high risk for gallbladder gangrene.

A virtual reality module for intravenous catheter placement

BACKGROUND Virtual reality (VR) is a potential tool for technical skills training. We tested the validity and instructional effectiveness of a prototype VR module for learning intravenous (i.v.) catheter placement. METHODS First-year medical students (n = 37), third-year medical students (n = 14), and surgical residents (n = 9) attempted two pretest i.v.s into each other, used the VR module for 12 minutes, and subsequently attempted two posttest i.v.s. Success or failure were recorded for each attempt. For each successful attempt, time and global rating of i.v. insertion were also recorded. RESULTS The pretest success rate was significantly different between groups (chi square = 28.71, P <0.01). VR success rate was not significantly different between groups (F(2,57) = 1.47, ns). Although there was improvement in all groups during VR training (F(2,114) = 44.16, P <0.01), this did not result in improvement in posttest performance. CONCLUSIONS Significant differences between groups were observed in performance of i.v. insertion in physical reality. However, no significant difference was observed in performance in VR. Thus, performance in VR demonstrated neither construct nor concurrent validity. While performance improved in VR, transfer of skill from VR to physical reality was not observed. Additional development and testing of VR as a training tool is warranted before its widespread use can be recommended.

Effect of Surgeon Training, Specialization, and Experience on Outcomes for Cancer Surgery: A Systematic Review of the Literature

BackgroundOutcomes after cancer resections have been shown to be better for high-volume surgeons compared with low-volume surgeons; however, reasons for this relationship have been difficult to identify. The objective of this study was to assess studies examining the effect of surgeon training and experience on outcomes in surgical oncology.MethodsA systematic review of the literature was performed to assess articles examining the impact of surgeon training, certification, and experience on outcomes. Studies were included if they examined cancer resections and performed multivariable analyses adjusting for relevant confounding variables.ResultsAn extensive literature search identified 29 studies: 27 examined surgeon training/specialization, 1 assessed surgeon certification, and 4 evaluated surgeon experience. Of the 27 studies examining training/specialization, 25 found that specialized surgeons had better outcomes than nonspecialized surgeons. One study found that American Board of Surgery (ABS)-certified surgeons had better outcomes than noncertified surgeons. Of the two studies examining time since ABS certification, both found that increasing time was associated with better outcomes. Of the four studies that examined experience, three studies found that increasing surgeon experience was associated with improved outcomes.ConclusionsAlthough numerous studies have examined the impact of surgeon factors on outcomes, only a few cancers have been examined, and outcome measures are inconsistent. Most studies do not appear robust enough to support major policy decisions. There is a need for better data sources and consistent analyses which assess the impact of surgeon factors on a broad range of cancers and help to uncover the underlying reasons for the volume–outcome association.

Development of a measure of attitude toward nutrition in patient care

BACKGROUND Development of reliable measures of medical student and resident attitudes about nutrition in patient care is needed before the effects of educational interventions or clinical experience can be gauged. This report describes the systematic development of a measure of attitude toward nutrition in patient care. It presents evidence about scale reliability and the absence of response bias that endorses the trustworthiness of data from the measure. METHODS An eight-step attitude scale development procedure was used to create the Nutrition In Patient care Survey (NIPS). Data from five samples of first- and second-year medical students and first-year medical residents were subjected to factor analysis (PA2, varimax rotation), reliability analyses, and statistical analyses to test for demographic bias in the attitude data. RESULTS A 45-item attitude measure was developed that contains five subscales derived from the factor analysis: (1) nutrition in routine care (NRC, 8 items); (2) clinical behavior (CB, 20 items); (3) physician-patient relationship (PPR, 8 items); (4) patient behavior/motivation (PBM, 3 items); and (5) physician efficacy (PE, 6 items). Each subscale yields reliable data in terms of internal consistency (alpha coefficients) and stability (test-retest reliability). Medical student and resident demographic variables have negligible influence on attitude scores. DISCUSSION The NIPS subscales yield reliable data that can be used to assess outcomes in evaluation research on educational or clinical interventions or to predict patient care practices. Systematic attitude scale development increases the likelihood that the resulting measures will produce useful, trustworthy data.

Optical properties of human gallbladder tissue and bile.

Knowledge of the optical properties of biliary tract tissues is useful for aiding in the development and understanding of clinical applications of lasers in the biliary tract. Human gallbladder and bile specimens were obtained during laproscopic cholecystectomy. The diffuse remittance and transmission of the samples were determined from 350 to 2450 nm. Collimated transmission was determined at 633 and 2100 nm. Using one-dimensional diffusion theory, we calculated micro(s), micro(a), and g as a function of wavelength. Both gallbladder and bile show absorption peaks at 1.4 and 1.9 microm. Bile has a peak at 400 nm; gallbladder has peaks at 410 and 550 nm. The absorption peaks are correlated with known tissue chromophores. The effect of the sample preparation on the results is discussed.

The Effects of Ultrasound-Guided Shock Waves During Early Pregnancy in Sprague-Dawley Rats

Pregnancy is a contraindication to extracorporeal shock wave lithotripsy (ESWL) because of its possible harm to the embryo or fetus caused by shock waves or ionizing radiation. In this study timed-pregnant rats were subjected to shock waves early in gestation using a lithotriptor having ultrasound imaging. In a pilot group undergoing immediate laparotomy, it was determined to what extent the pelvic structures were effected. Then a test group was exposed to shock waves and carried to near term pregnancy along with an identical group of pregnant, sham procedure rats. A laparotomy all were inspected for fetal viability, fetal abnormalities, and maternal organ damage. Fetuses located nearest the focal area of maximum shock wave energy showed lower mean weight than controls. There was no recognizable gross or microscopic fetal damage.

Prevention of thromboembolic events in surgical patients through the creation and implementation of a computerized risk assessment program

OBJECTIVES Deep vein thrombosis (DVT) is a major source of postoperative morbidity and mortality and is currently a major quality improvement initiative. Mechanical and pharmacological prophylaxis is effective in preventing postoperative thromboembolic events, yet it remains underutilized in the clinical setting. Thus, the objective of this study was to develop and implement a computerized DVT risk assessment program in the electronic medical record and determine its effect on compliance with DVT prophylaxis guidelines. METHODS A standardized DVT risk assessment program was developed and incorporated into the Computerized Patient Record System for all surgical patients at the Jesse Brown Veterans Affairs Medical Center. Four hundred consecutive surgical patients before and after implementation were evaluated for DVT risk, the prescription of pharmacological and mechanical DVT prophylaxis, and the development of thromboembolic events. RESULTS With implementation of the DVT risk assessment program, the number of patients receiving the recommended pharmacological prophylaxis preoperatively more than doubled (14% to 36%) (P < .001), and use of sequential compression devices (SCD) increased 40% (P < .001). Overall, the percentage of at-risk patients receiving the recommended combined DVT prophylaxis of SCD and pharmacological prophylaxis increased nearly seven-fold (5% to 32%) (P < .001). The assessment also improved use of prophylaxis postoperatively, increasing SCD use by 27% (P < .001). With respect to DVT occurrence, there was an 80% decrease in the incidence of postoperative DVT at 30 days and a 36% decrease at 90 days; however, this did not reach statistical significance due to the low event rate. CONCLUSIONS The creation and implementation of a standardized DVT risk assessment program in the electronic medical record significantly increased use of pharmacological and mechanical DVT prophylaxis before surgery in a Veterans Affairs Medical Center setting.

Revisional bariatric surgery at a single institution.

BACKGROUND Bariatric surgery, although safe, can have long-term complications that require revision. Our series illustrates the spectrum of primary procedures, indications for surgery, and strategies for revision. METHODS The study was a retrospective chart review. Sixty-three patients were identified. Of specific interest were complications and percentage of excess weight loss (EWL) during the follow-up period. RESULTS Eighteen patients had a previous vertical banded gastroplasty (VBG), 26 had a Roux-en-Y gastric bypass (RYGB), 18 had a laparoscopic adjustable gastric banding (LAGB), and 1 had a jejunal-ileal bypass. All VBG patients were revised to RYGB. Seventeen RYGB patients were revised with RYGB. Eight LAGB patients were revised with RYGB. Eight RYGB patients had placement of LAGB. Two LAGB patients were revised with LAGB because of a slipped band. Eight LAGB patients had the band removed. The morbidity rate was 30% with a major morbidity rate of 11%. There were 2 leaks, neither required reoperation. Other major complications included 3 pneumonias, 2 reoperations, and 2 intra-abdominal abscesses. There were no mortalities. In the 15 patients who had conversion of VBG to RYGB, the mean EWL was 50%, with 60% of patients achieving more than 50% EWL. In the 10 patients who had revision of their RYGB, the mean EWL was 51%, with 60% of patients achieving more than 50%. In the 6 patients who had revision of LAGB to RYGB, the mean EWL was 39%, with 33% of patients achieving more than 50% EWL. In the 8 patients who had LAGB after RYGB the mean EWL was -2%, with 0% of patients achieving more than 50%. CONCLUSIONS Revisional surgery is effective, although complication rates are higher than primary bariatric surgery. The type of initial and revisional procedure affects EWL.