R. Armour Forse

Development and Validation of a Risk Calculator for Prediction of Cardiac Risk After Surgery

Background— Perioperative myocardial infarction or cardiac arrest is associated with significant morbidity and mortality. The Revised Cardiac Risk Index is currently the most commonly used cardiac risk stratification tool; however, it has several limitations, one of which is its relatively low discriminative ability. The objective of the present study was to develop and validate a predictive cardiac risk calculator. Methods and Results— Patients who underwent surgery were identified from the American College of Surgeons 2007 National Surgical Quality Improvement Program database, a multicenter (>250 hospitals) prospective database. Of the 211 410 patients, 1371 (0.65%) developed perioperative myocardial infarction or cardiac arrest. On multivariate logistic regression analysis, 5 predictors of perioperative myocardial infarction or cardiac arrest were identified: type of surgery, dependent functional status, abnormal creatinine, American Society of Anesthesiologists class, and increasing age. The risk model based on the 2007 data set was subsequently validated on the 2008 data set (n=257 385). The model performance was very similar between the 2007 and 2008 data sets, with C statistics (also known as area under the receiver operating characteristic curve) of 0.884 and 0.874, respectively. Application of the Revised Cardiac Risk Index to the 2008 National Surgical Quality Improvement Program data set yielded a relatively lower C statistic (0.747). The risk model was used to develop an interactive risk calculator. Conclusions— The cardiac risk calculator provides a risk estimate of perioperative myocardial infarction or cardiac arrest and is anticipated to simplify the informed consent process. Its predictive performance surpasses that of the Revised Cardiac Risk Index.

Fat Depot–Specific Characteristics Are Retained in Strains Derived From Single Human Preadipocytes

Fat depots vary in size, function, and potential contribution to disease. Since fat tissue turns over throughout life, preadipocyte characteristics could contribute to this regional variation. To address whether preadipocytes from different depots are distinct, we produced preadipocyte strains from single abdominal subcutaneous, mesenteric, and omental human preadipocytes by stably expressing human telomere reverse transcriptase (hTERT). These strains could be subcultured repeatedly and retained capacity for differentiation, while primary preadipocyte adipogenesis and replication declined with subculturing. Primary omental preadipocytes, in which telomeres were longest, replicated more slowly than mesenteric or abdominal subcutaneous preadipocytes. Even after 40 population doublings, replication, abundance of the rapidly replicating preadipocyte subtype, and resistance to tumor necrosis factor α–induced apoptosis were highest in subcutaneous, intermediate in mesenteric, and lowest in omental hTERT-expressing strains, as in primary preadipocytes. Subcutaneous hTERT-expressing strains accumulated more lipid and expressed more adipocyte fatty acid–binding protein (aP2), peroxisome proliferator–activated receptor γ2, and CCAAT/enhancer-binding protein α than omental cells, as in primary preadipocytes, while hTERT abundance was similar. Thus, despite dividing 40 population doublings, hTERT strains derived from single preadipocytes retained fat depot–specific cell dynamic characteristics, consistent with heritable processes contributing to regional variation in fat tissue function.

Team training can improve operating room performance

BACKGROUNDnThis study was conducted to determine if team training using a federally sponsored team training program improves operating room (OR) performance and culture.nnnMETHODSnThe TeamSTEPPS program, a team training program designed and tested for health care applications, was provided to the OR staff. The training occurred over 2 months to all members of the OR team, including scrub technicians, nurses, certified registered nurse anesthetists, anesthesiologists, surgeons, and all anesthesiology and surgical resident staff.nnnRESULTSnAfter 9 months, there was a significant improvement in the OR staff team work (score 53.2 to 62.7; P < .05) and OR communications (score 47. 5 to 62.7; P < .05). There was significant improvement in OR first case starts (69% to 81%), Surgical Quality Improvement Program measures (antibiotic administration, 78% to 97% [P < .05]; venous thromboembolism administration, 74% to 91% [P < .05]; and beta blocker administration, 19.7% to 100%; P < .05) and patient satisfaction (willingness to recommend, 77% to 89.3% [P < .05]). NSQIP measured overall surgical morbidity and mortality, which were both significantly improved (mortality, 2.7% to 1% [P < .05]; morbidity, 20.2% to 11.0% [P < .05]), indicating a significant change in the overall OR culture. A year later, the data showed that factors linked to regulatory requirements, such as Surgical Quality Improvement Program measures linked to the time out remained improved while first case on time starts decreased (81% to 69%; P < .05), patient willingness to recommend decreased (89.3% to 80.8%; P < .05), surgical mortality increased (1% to 1.5%; P < .05), and surgical morbidity increased (11% to 13%; P < .05) reflecting a degree of culture deterioration which has persisted.nnnCONCLUSIONnThese data confirm that team training improves OR performance, but continued team training is required to provide sustained improved OR culture.

Development and Validation of a Bariatric Surgery Morbidity Risk Calculator Using the Prospective, Multicenter NSQIP Dataset

BACKGROUNDnAlthough a risk score estimating postoperative mortality for patients undergoing gastric bypass exists, there is none predicting postoperative morbidity. Our objective was to develop a validated risk calculator for 30-day postoperative morbidity of bariatric surgery patients.nnnSTUDY DESIGNnWe used the American College of Surgeons 2007 National Surgical Quality Improvement Program (NSQIP) dataset. Patients undergoing bariatric surgery for morbid obesity were studied. Multiple logistic regression analysis was performed and a risk calculator was created. The 2008 NSQIP dataset was used for its validation.nnnRESULTSnIn 11,023 patients, mean age was 44.6 years, 20% were male, 77% were Caucasian, and mean body mass index (BMI; calculated as kg/m(2)) was 48.9. Thirty-day morbidity and mortality were 4.2% and 0.2%, respectively. Risk factors associated with increased risk of postoperative morbidity included recent MI/angina (odds ratio [OR] = 3.65; 95% CI 1.23 to 10.8), dependent functional status (OR = 3.48; 95% CI 1.78 to -6.80), stroke (OR = 2.89; 95% CI 1.09 to 7.67), bleeding disorder (OR = 2.23; 95% CI 1.47 to 3.38), hypertension (OR = 1.34; 95% CI 1.10 to 1.63), BMI, and type of bariatric surgery. Patients with BMI 35 to <45 and >60 had significantly higher adjusted OR compared with patients with BMI of 45 to 60 (p < 0.05 for all). These factors were used to create the risk calculator and subsequently validate it, with the model performance very similar between the 2007 training dataset and the 2008 validation dataset (c-statistics: 0.69 and 0.66, respectively).nnnCONCLUSIONSnNSQIP data can be used to develop and validate a risk calculator that predicts postoperative morbidity after various bariatric procedures. The risk calculator is anticipated to aid in surgical decision making, informed patient consent, and risk reduction.

Development and Validation of a Risk Calculator Predicting Postoperative Respiratory Failure

BACKGROUNDnPostoperative respiratory failure (PRF) (requiring mechanical ventilation > 48 h after surgery or unplanned intubation within 30 days of surgery) is associated with significant morbidity and mortality. The objective of this study was to identify preoperative factors associated with an increased risk of PRF and subsequently develop and validate a risk calculator.nnnMETHODSnThe American College of Surgeons National Surgical Quality Improvement Program (NSQIP), a multicenter, prospective data set (2007-2008), was used. The 2007 data set (n = 211,410) served as the training set and the 2008 data set (n = 257,385) as the validation set.nnnRESULTSnIn the training set, 6,531 patients (3.1%) developed PRF. Patients who developed PRF had a significantly higher 30-day mortality (25.62% vs 0.98%, P < .0001). On multivariate logistic regression analysis, five preoperative predictors of PRF were identified: type of surgery, emergency case, dependent functional status, preoperative sepsis, and higher American Society of Anesthesiologists (ASA) class. The risk model based on the training data set was subsequently validated on the validation data set. The model performance was very similar between the training and the validation data sets (c-statistic, 0.894 and 0.897, respectively). The high c-statistics (area under the receiver operating characteristic curve) indicate excellent predictive performance. The risk model was used to develop an interactive risk calculator.nnnCONCLUSIONSnPreoperative variables associated with increased risk of PRF include type of surgery, emergency case, dependent functional status, sepsis, and higher ASA class. The validated risk calculator provides a risk estimate of PRF and is anticipated to aid in surgical decision making and informed patient consent.

Development and Validation of a Bariatric Surgery Mortality Risk Calculator

BACKGROUNDnWhile the epidemic of obesity continues to plague America, bariatric surgery is underused due to concerns for surgical risk among patients and referring physicians. A risk score estimating postoperative mortality (OS-MRS) exists, however, is limited by consideration of only 12 preoperative variables, failure to separate open and laparoscopic cases, a lack of robust statistical analyses, risk factors not being weighted, and being applicable to only gastric bypass surgery. The objective of this study was to develop a validated risk calculator for 30-day postoperative mortality after bariatric surgery.nnnSTUDY DESIGNnThe National Surgical Quality Improvement Program (NSQIP) dataset (2006 to 2008) was used. Patients undergoing bariatric surgery for morbid obesity (n = 32,889) were divided into training (n = 21,891) and validation (n = 10,998) datasets. Multiple logistic regression analysis was performed on the training dataset. The model fit from the training dataset was maintained and was used to estimate mortality probabilities for all patients in the validation dataset.nnnRESULTSnThirty-day mortality was 0.14%. Seven independent predictors of mortality were identified: peripheral vascular disease, dyspnea, previous percutaneous coronary intervention, age, body mass index, chronic corticosteroid use, and type of bariatric surgery. This risk model was subsequently validated. The model performance was very similar between the training and the validation datasets (c-statistics, 0.80 and 0.82, respectively). The high c-statistics indicate excellent predictive performance. The risk model was used to develop an interactive risk calculator.nnnCONCLUSIONSnThis risk calculator has excellent predictive ability for mortality after bariatric procedures. It is anticipated that it will aid in surgical decision-making, informed patient consent, and in helping patients and referring physicians to assess the true bariatric surgical risk.

Carcinoembryonic antigen (CEA) and its receptor hnRNP M are mediators of metastasis and the inflammatory response in the liver

This article discusses the role of carcinoembryonic antigen (CEA) as a facilitator of the inflammatory response and its effect on colorectal cancer hepatic metastasis. Colorectal cancer accounts for 11% of all cancers in the United States and the majority of deaths are associated with liver metastasis. If left untreated, median survival is only six to 12xa0months. Resection of liver metastases offers the only chance for cure. Of the small number of patients who have operable cancer most will have further tumor recurrence. The molecular mechanisms associated with colorectal cancer metastasis to the liver are largely unknown. However CEA production has been shown both clinically and experimentally to be a factor in an increased metastatic potential of colorectal cancers to the liver. CEA also has a role in protecting tumor cells from the effects of anoikis and this affords a selective advantage for tumor cell survival in the circulation. CEA acts in the liver through its interaction with its receptor (CEAR), a protein that is related to the hnRNP M family of RNA binding proteins. In the liver CEA binds with hnRNP M on Kupffer cells and causes activation and production of pro- and anti-inflammatory cytokines including IL-1, IL-10, IL-6 and TNF-α. These cytokines affect the up-regulation of adhesion molecules on the hepatic sinusoidal endothelium and protect the tumor cells against cytotoxicity by nitric oxide (NO) and other reactive oxygen radicals. HnRNP M signaling in Kupffer cells appears to be controlled by beta-adrenergic receptor activation. The cells will respond to the β-adrenergic receptor agonist terbutaline resulting in reduced TNF-α and increased IL-10 and IL-6 production following CEA activation. This has implications for the control of tumor cell implantation and survival in the liver.

Clinical practice. Groin hernias in adults

Key Clinical PointsGroin Hernias in Adults Groin hernias are much more common in men than in women. Patients with symptoms of acute incarceration and strangulation require emergency surgery. Watchful waiting is a safe approach for asymptomatic male patients with inguinal hernia, but data from randomized trials suggest that the majority of men will ultimately be referred for surgery, primarily because of pain, within 10 years. For an uncomplicated unilateral inguinal hernia, open repair has the advantages of potentially being performed under local anesthesia and incurring lower initial costs; laparoscopic repair results in less postoperative pain and an earlier return to normal activities, but it requires general anesthesia routinely and carries a small risk of major intraabdominal injury. Femoral hernias occur more often in women than in men, are associated with much higher risk of strangulation, and can be difficult to distinguish from inguinal hernias; watchful waiting is not recommended in women.

OUTCOMES AFTER THYROIDECTOMY AND PARATHYROIDECTOMY

Previous reports on postoperative outcomes following thyroid and parathyroid surgery are limited by relatively small sample size. We report 30‐day outcomes following thyroid and parathyroid surgery and analyze factors affecting length of stay (LOS) and postoperative adverse events (AEs).

Preoperative weight gain might increase risk of gastric bypass surgery

BACKGROUNDnWeight loss improves the cardiovascular and metabolic risk associated with obesity. However, insufficient data are available about the health effects of weight gain, separate from the obesity itself. We sought to determine whether the changes in body weight before open gastric bypass surgery (OGB) would have a significant effect on the immediate perioperative hospital course.nnnMETHODSnA retrospective chart review of 100 consecutive patients was performed to examine the effects of co-morbidities and body weight changes in the immediate preoperative period on the hospital length of stay and the rate of admission to the surgical intensive care unit (SICU).nnnRESULTSnOf our class III obese patients undergoing OGB, 95% had ≥1 co-morbid condition and an overall SICU admission rate of 18%. Compared with the patients with no perioperative SICU admission, the patients admitted to the SICU had a greater degree of insulin resistance (homeostatic model analysis-insulin resistance 10.8 ± 1.3 versus 5.9 ± 0.5, P = .001), greater serum triglyceride levels (225 ± 47 versus 143 ± 8 mg/dL, P = .003), and had gained more weight preoperatively (.52 ± .13 versus .06 ± .06 lb/wk, P = .003). The multivariate analyses showed that preoperative weight gain was a risk factor for a longer length of stay and more SICU admissions lasting ≥3 days, as were a diagnosis of sleep apnea and an elevated serum triglyceride concentration.nnnCONCLUSIONnThe results of the present retrospective study suggest that weight gain increases the risk of perioperative SICU admission associated with OGB, independent of the body mass index. Sleep apnea and elevated serum triglyceride levels were also important determinants of perioperative morbidity. In view of the increasing epidemic of obesity and the popularity of bariatric surgical procedures, we propose that additional clinical and metabolic research focusing on the understanding of the complex relationship among obesity, positive energy balance, weight gain, and perioperative morbidity is needed.