The shortage of donor organs highlights the need to better identify patients most likely to benefit from hepatic transplantation. Reduced aerobic capacity (decreased peak oxygen consumption [VO(2)] during symptom-limited cardiopulmonary exercise testing) is frequently present in cirrhosis. Peak VO(2) during cardiopulmonary exercise testing may predict short-term outcome after hepatic transplantation. Symptom-limited testing was performed on a cycle ergometer (continuous ramp protocol) and VO(2) determined using a metabolic cart. One hundred fifty-six patients were tested; 59 subsequently underwent hepatic transplantation. Results showed that survivors and nonsurvivors were similar in age, duration of liver disease, Child-Pugh score, MELD score, resting cardiovascular function, pulmonary function, and gas exchange. The 6 (10.2%) patients dying within 100 days of transplantation were more likely to have reduced aerobic capacity (peak VO(2)<60% predicted and VO(2) at anaerobic threshold [VO(2)-AT]<50% predicted peak VO(2)) compared to survivors (4/6 vs. 7/53, P <.01). Using a multiple logistic regression model controlling for duration and severity of liver disease and time to transplantation, reduced aerobic capacity was independently associated with 100-day mortality. In conclusion, reduced aerobic capacity during cardiopulmonary exercise testing is associated with decreased short-term survival after hepatic transplantation. Further study is needed to determine if cardiopulmonary exercise testing can be used to improve allocation of donor organs. To ensure optimum allocation of donor organs, it is important to identify patients most likely to benefit from transplantation. Investigators have identified a number of preoperative, intraoperative, and postoperative factors that predict increased risk for postoperative mortality. Unfortunately, predictive accuracy has not been high, and the timing of factor identification does not optimize organ utilization. Identification of predictors of survival at the time of listing for transplantation might lead to better resource allocation.(Liver Transpl 2004;10:418-424.)

BACKGROUND: Reducing postprandial blood glucose concentrations in diabetic patients might contribute to optimal glycemic control. Gastrointestinal electrical stimulation has been proposed as a novel therapy for both gastrointestinal motility disorders and obesity. The present study investigated the effects and underlying mechanisms of intestinal electrical stimulation (IES) on postprandial blood glucose levels in rats. METHODS: Electrical stimulation electrodes were implanted into the duodenal wall of 33 male Sprague-Dawley rats. The blood glucose and insulin levels were measured before and after a glucose tolerance test both with and without electrical stimulation. In addition, the gastric emptying and intestinal flow rates were measured. RESULTS: IES applied immediately after the glucose tolerance test caused a significant decrease in the rising phase slope and the maximal serum blood glucose level. Additionally, the area under the curve of the blood glucose levels was reduced by approximately 50%. Insulin secretion decreased by 21%. The main reduction in insulin secretion was during the first 30 minutes after the glucose tolerance test. IES also caused a nearly 80% decrease of the gastric emptying rate and a 40% increase in the flow rate of nutrients inside the intestine. The effect was immediate after IES activation and reversible. CONCLUSION: These results suggest that IES applied to the duodenum can reduce postprandial blood glucose levels. The possible etiology is the modulating of gastric emptying and intestinal flow rate.

BACKGROUND: The bladed optical access trocar is widely used and provides convenient, safe peritoneal entry. However, it has only been approved for use after insufflation. We used this device as our primary method of entry before insufflation in bariatric surgery and provide an overview of our cumulative experience. In addition, we provide a comprehensive analysis of the published data with respect to optical access as both primary and secondary methods of peritoneal access. METHODS: From July 30, 2001 to April 4, 2008, laparoscopic access for all bariatric surgery at a single center was achieved using the 5-12-mm optical bladed trocar without previous insufflation for 2207 cases, including 1692 laparoscopic gastric bypass procedures and 515 laparoscopic adjustable gastric band placements. RESULTS: Four vascular injuries occurred (.18%) in our series. Three required conversion to laparotomy and vascular repair, and one was managed laparoscopically. All injuries occurred with off-midline placement. No mortalities occurred secondary to the use of the optical trocar. CONCLUSION: The present report is as the greatest volume series detailing the safe and effective use of the bladed optical trocar without previous insufflation as the primary method of peritoneal access in the morbidly obese. The insertion of this device in the midline appears to be a safe method of entry.

To update evidence-based best practice guidelines for surgical care in weight loss surgery (WLS). Systematic search of English-language literature on WLS in MEDLINE, EMBASE, and the Cochrane Library between April 2004 and May 2007. Use of key words to narrow the search for a selective review of abstracts, retrieval of full articles, and grading of evidence according to systems used in established evidence-based models. Evidence-based best practice recommendations from the most recent literature on surgical methods and technologies, risks and benefits, outcomes, and surgeon qualifications and credentialing. We identified >135 articles; the 65 most relevant were reviewed in detail. Regular updates of evidence-based recommendations for best practices in WLS are required to address rapid changes in surgical techniques and patient demographics. Key factors in patient safety include surgical risk factors, type of procedure, surgeon training, and facility certification.Obesity (2009) 17 5, 863-870. doi:10.1038/oby.2008.570.

BACKGROUND: The aim of this study is to clarify whether laparoscopic sleeve gastrectomy (LSG) to treat morbid obesity causes changes in gastric emptying. METHODS: Gastric emptying scintigraphy was performed before and 3 months after LSG, in 21 consecutive morbidly obese patients. After an overnight fast, subjects consumed a standard semi-solid meal, to which 0.5 mCi Tc(99)-labeled sulfur colloid had been added. The meal was consumed within 10 min. Scintigraphic imaging was performed with a gamma camera immediately after the completion of the meal as well as after 30, 60, 120, 180, and 240 min. Quantitative and qualitative analysis was performed by drawing a region of interest (ROI) enclosing the stomach on the anterior and the posterior images. Time 0 was considered the time of meal completion (all the ingested activity) and was defined as 100% retention. The same ROI was used on all consecutive images of the same projection for the same patient. The geometric mean of the anterior and the posterior counts for each time point is calculated and corrected for Tc(99m) decay. Gastric emptying curves were constructed. T 1/2 is the time interval between completion of the meal and the point at which half of the meal (by radioactivity counts) has left the stomach. Retention is expressed as the percent remaining in the stomach at each time point (half, 1, 2, 3, 4 h). RESULTS: The mean T 1/2 raw data was 62.39 +/- 19.83 and 56.79 +/- 18.72 min (p = 0.36, t =-0.92, NS) before and 3 months after LSG, respectively. The T 1/2 linear was 103.64 +/- 9.82 and 106.92 +/- 14.55,(p = 0.43, t =-0.43, NS), and the linear fit slope 0.48 +/- 0.04 and 0.47 +/- 0.05 (p = 0.48, t = 0.7, NS). CONCLUSIONS: LSG with antrum preservation as performed in this series has no effect on gastric emptying.

BACKGROUND: Aiming to clarify the mechanism of weight loss after the restrictive bariatric procedure of sleeve gastrectomy (LSG), the volumes and pressures of the stomach, of the removed part, and of the remaining sleeve were measured in 20 morbidly obese patients. METHODS: The technique used consisted of occlusion of the pylorus with a laparoscopic clamp and of the gastroesophageal junction with a special orogastric tube connected to a manometer. Instillation of methylene-blue-colored saline via the tube was continued until the intraluminal pressure increased sharply, or the inflated stomach reached 2,000 cc. After recording of measurements, LSG was performed. RESULTS: Mean volume of the entire stomach was 1,553 cc (600-2,000 cc) and that of the sleeve 129 cc (90-220 cc), i.e., 10%(4-17%) and that of the removed stomach was 795 cc (400-1,500 cc). The mean basal intragastric pressure of the whole stomach after insufflations of the abdominal cavity with CO(2) to 15 mmHg was 19 mmHg (11-26 mmHg); after occlusion and filling with saline it was 34 mmHg (21-45 mmHg). In the sleeved stomach, mean basal pressure was similar 18 mmHg (6-28 mmHg); when filled with saline, pressure rose to 43 mmHg (32-58 mmHg). The removed stomach had a mean pressure of 26 mmHg (12-47 mmHg). There were no postoperative complications and no mortality. CONCLUSIONS: The notably higher pressure in the sleeve, reflecting its markedly lesser distensibility compared to that of the whole stomach and of the removed fundus, indicates that this may be an important element in the mechanism of weight loss.

Primary care providers face significant challenges in the treatment of patients with obesity. This article reviews issues of concern to primary care clinicians who seek the best outcomes for this patient population.

OBJECTIVE:: To determine whether extreme obesity (morbid obesity; body mass index >/=40 kg/m) is an independent risk factor for death among critically ill patients; this objective is most salient in the subset of patients who sustain a prolonged intensive care unit stay during which the burdens of care imposed by obesity and its consequences would become most apparent. DESIGN:: Cohort analysis of data from the Project Impact database used to catalog admissions and outcomes to a surgical intensive care unit, with predetermined end point analyses of outcomes. SETTING:: Surgical intensive care unit serving Tufts-New England Medical Center, a tertiary care and university medical center in Boston. PATIENTS:: All critically ill surgical patients admitted Tufts-New England Medical Center surgical intensive care unit from January 1998 to March 2001. INTERVENTIONS:: Intensive care unit and hospital mortality and lengths of stay were compared with body mass index subclassified into five groups: underweight, normal weight, overweight, obese, and extremely obese. Data were examined for all admissions during the study period and for a predetermined subgroup with a prolonged intensive care unit stay (>/=4 days). MEASUREMENTS AND MAIN RESULTS:: The prevalence of obesity in the surgical intensive care unit was 26.7%; extreme obesity was observed in 6.8%. In the full cohort of patients (n = 1373), median length of stay was short (2 days) and there were no differences in mortality in patients among any of the body mass index classes. In the subgroup of prolonged stay patients (n = 406), intensive care unit and hospital mortality rates were significantly increased in extremely obese patients compared with all other patients (intensive care unit, 33.3% vs. 12.3%, p =.009; hospital, 33.3% vs. 16%, p =.045). Multivariate analysis showed that extreme obesity was an independent predictor of death in surgical critically ill patients with prolonged intensive care unit stay after controlling for age, gender, and severity of illness. The odds of death increased 7.4 times in patients with morbid obesity. CONCLUSIONS:: Morbid obesity (body mass index >/=40 kg/m) is an independent risk factor for death in surgical patients with catastrophic illness requiring prolonged intensive care. The prevalence of obesity is growing, both in the intensive care unit and in the general population. The increased risk of complications and death in this population mandates that we adapt customized processes of care to specifically address this unique and very challenging subset of patients. LEARNING OBJECTIVES: On completion of this article, the reader should be able to:Dr. Shikora has disclosed that he is the recipient of direct grant/research funds from U.S. Surgical Corp., Medtronics, and Synovis Surgical Innovations. All of the remaining authors have disclosed that they have no financial relationships with or interests in any commercial companies pertaining to this educational activity.Wolters Kluwer Health has identified and resolved all faculty conflicts of interest regarding this educational activity.Visit the Critical Care Medicine Web site (www.ccmjournal.org) for information on obtaining continuing medical education credit.

OBJECTIVE: To provide evidence-based guidelines on the specialized personnel, equipment, and physical plant required for safe and effective care of severely obese weight loss surgery (WLS) patients. RESEARCH METHODS AND PROCEDURES: We examined MEDLINE (Ovid and PubMed) and the Cumulative Index of Nursing and Allied Health Literature for articles on facilities resources for care of WLS patients published in English between January 1980 and March 2004. We queried several web sites for appropriate references; these included the Agency for Healthcare Research and Quality and the American College of Surgeons. The majority of reference material was descriptive and not specific to facilities resources for WLS patients. We identified a substantial body of literature on the general subject of patient safety; three of these articles were used to develop recommendations on the use of technology for medical error reduction. All other recommendations are based on 11 expert opinion reports. RESULTS: We recommended adequate training and credentialing for all medical staff; dedicated support and administrative personnel; and specialized interventional, diagnostic, operating room, and transport equipment. We specified needed adaptations to the physical plant and developed evidence-based guidelines for medical error reduction and systems improvements. DISCUSSION: Specialized resources and dedicated staff are needed to protect the health of WLS surgery patients and staff. Adaptations include preoperative preparation for safe means of patient transport; techniques of anesthesia and intraoperative exposure; provisions for postoperative recovery; and measures to assure postoperative patient safety, hygiene, and comfort.

RATIONALE: The influence of obesity on the perception of respiratory discomfort during acute bronchoconstriction in asthma is unknown. OBJECTIVE: We hypothesized that the respiratory impairment associated with an increased BMI would predispose to greater perceived symptom intensity during acute airway narrowing. We therefore compared relationships between induced changes in dyspnea intensity and lung function during methacholine (MCh) bronchoprovocation in obese (OBA) and normal-weight asthmatics (NWA) of mild to moderate severity. METHODS: High-dose MCh challenge tests to a maximum 50% decrease in FEV1 were conducted in 51 NWA (BMI 18.5-24.9 kg/m(2), 29% male) and 45 OBA (BMI 30.1-51.4 kg/m(2), 33% male) between 20-60 years of age. Serial spirometry, inspiratory capacity (IC), plethysmographic endexpiratory lung volume (EELV) and dyspnea intensity using the Borg scale were measured throughout bronchoprovocation. MEASUREMENTS AND MAIN RESULTS: Spirometry and airway sensitivity were similar in both groups; baseline EELV was lower (p<0.0005) and IC was higher (p=0.007) in OBA compared with NWA. From baseline to PC20, EELV increased more in OBA (20%predicted) than NWA (13%predicted)(p=0.008) with concomitant greater reductions in IC (p<0.0005). Dyspnea ratings were not different for a given FEV1 or IC across groups. By mixed effects regression analysis, relationships between induced dyspnea and changes in lung function parameters were not influenced by BMI, gender or their interaction. CONCLUSIONS: Perceptual responses to MCh-induced bronchoconstriction and lung hyperinflation were similar in obese and normal-weight asthmatics despite significant group differences in baseline lung volumes.

Obesity places a significant load on the respiratory system, affecting lung volumes, respiratory muscle function, work of breathing and ventilatory control. Despite this, most morbidly obese individuals maintain eucapnia. However, a subgroup of morbidly obese individuals will develop chronic daytime hypercapnia, described as the obesity hypoventilation syndrome. While obesity is obviously a crucial component of this syndrome, the relationship between excess fat accumulation and the development of awake hypercapnia is complex and extends beyond simply impairments of pulmonary mechanics and lung volumes as a consequence of obesity. Various compensatory mechanisms operate to maintain eucapnia even in the presence of extreme obesity. However, if compensation is impaired, hypoventilation will ensue. While obesity alone does not account for the development of hypoventilation, weight loss will produce significant improvements in lung function and awake gas exchange. Such improvements have the potential to substantially reduce morbidity and mortality in these individuals. Nevertheless, many individuals remain overweight despite substantial weight loss, with persistence of upper airway obstruction. Attention to this residual abnormality is important given the high incidence of cardiovascular abnormalities, including pulmonary hypertension, in individuals with OHS. Key words: Obesity hypoventilation, Pulmonary function, weight loss, hypercapnia.

Assessment of dyspnea can be a challenging task even for experienced physicians. Dyspnea can be caused by multiple reasons in up to one third of the cases. By history taking and physical examinations only, airway obstruction can be missed as well as over-diagnosed. Therefore, spirometry is an important tool in the assessment of dyspnea. Spirometry should be performed in a high standard quality respecting the international quality criteria, thus spirometry can be interpreted securely and provide the asked information.

BACKGROUND: Even several days after surgery, obese patients exhibit a measureable amount of atelectasis and thus are predisposed to postoperative pulmonary complications. Particularly in ambulatory surgery, rapid recovery of pulmonary function is desired to ensure early discharge of the obese patient. In this study, we wanted to evaluate intensive short-term respiratory physical therapy treatment (incentive spirometry) in the postanesthesia care unit (PACU) and its impact on pulmonary function in the obese. METHODS: After ethics committee approval and informed consent, we prospectively studied 60 obese patients (BMI 30-40) undergoing minor peripheral surgery, half of which were randomly assigned to receive respiratory physiotherapy during their PACU stay, while the others received routine treatment. Premedication, general anesthesia, and respiratory settings were standardized. We measured arterial oxygen saturation by pulse oximetry on air breathing. Inspiratory and expiratory lung functions were measured preoperatively (baseline) and at 10 min, 1, 2, 6, and 24 h after extubation, with the patient supine, in a 30 degrees head-up position. The two groups were compared using repeated-measure analysis of variance and t test analysis. Statistical significance was considered to be P < 0.05. RESULTS: There were no differences at the first assessment, but, during the PACU stay, pulmonary function in the physiotherapy group was significantly better than the controls'(p < 0.0001), an effect which persisted for at least 24 h after surgery (p < 0.009). CONCLUSION: Short-term respiratory physiotherapy during the PACU stay promotes more rapid recovery of postoperative lung function in the obese during the first 24 h.

BACKGROUND AND OBJECTIVES: Ventilation strategies for anesthesia in morbidly obese patients have been investigated, but an agreement has not been achieved yet. This study aimed at clinically evaluating ventilation adjustments based on oximetry and capnography readings in these patients during anesthesia. METHODS: Consent was obtained from the Institutional Ethics Committee and from patients. Smokers and respiratory or cardiac disease patients were excluded. Eleven patients with Body Mass Index (BMI) of 59.2 +/- 8.3 undergoing gastroplasty under general anesthesia were studied (Group O), with a control group (NO) composed of 8 non-obese patients (BMI 20.2 +/- 3.9) submitted to gastrectomy. Ventilator was adjusted to keep P ET CO2 below 40 mmHg and SpO2 above 95%. PEEP was not used. Through a CO2SMO Plus respiratory monitor, airway, alveolar and physiologic dead spaces (respectively VD aw, VD phy and VD alv), as well as alveolar tidal volume (TV alv) were measured. Arterial and central venous blood samples were used to calculate PaO2/FIO2 and VD phy/TV relationships. Data were compared and evaluated by ANOVA (p < 0.05). RESULTS: Tidal volume was 4.2 +/- 0.4 mL.kg-1 in Group O and 7.9 +/- 2.3 mL.kg-1 in Group NO for measured weight, and 11.5 +/- 1.8 mL.kg-1 in Group O and 6.6 +/- 1.1 mL.kg-1 in Group NO for ideal weight. PaO2 was lower and TV alv was higher in Group O (p < 0.008 and 0.0001, respectively). No difference was found in PaCO2, VD phy, VD alv and VD aw. CONCLUSIONS: SpO2 and P ET CO2 seem to assure adequate ventilation, which can be achieved in morbidly obese patients with tidal volumes adjusted to ideal weight.

BACKGROUND: The load that increased body mass imposes on ventilation contributes to the respiratory symptoms caused by obesity. We wished to quantify ventilatory load and respiratory drive in obesity, in both the upright and supine posture. Patients& METHODS: We studied resting breathing seated and supine in 30 obese (body-mass-index (BMI) 42.8(8.6)kg/m(2)) and 30 normal subjects (BMI 23.6(3.7)kg/m(2)) recording the electromyogram of the diaphragm (EMGdi, transoesophageal multipair electrode), gastric and oesophageal pressures. RESULTS: Ventilatory load and neural drive were higher in the obese group as judged by the EMGdi (21.9(9.0) vs 8.4(4.0)%max, p<0.001) and oesophageal pressure swings (9.6(2.9) vs 5.3(2.2)cmH2O, p<0.001). The supine posture caused an increase in oesophageal pressure swings to 16.0(5.0)cmH2O in obese (p<0.001) and to 6.9(2.0)cmH2O in non-obese subjects (p<0.001). The EMGdi increased in the obese group to 24.7(8.2)%max (p<0.001) but remained the same in non-obese subjects (7.0(3.4)%max, p=ns). Obese subjects developed intrinsic positive end-expiratory pressure (PEEPi) of 5.3(3.6)cmH2O when supine. Applying continuous positive airway pressure (CPAP) in a subgroup of obese subjects, supine, reduced the EMGdi by 40%, inspiratory pressure swings by 25% and largely abolished PEEPi (4.1(2.7) vs 0.8(0.4)cmH2O, p=0.009). CONCLUSION: Obese patients have substantially elevated neural drive related to BMI, and develop PEEPi when supine. CPAP abolishes PEEPi and reduces neural respiratory drive in such patients. These findings highlight the adverse respiratory consequences of obesity and have implications for the clinical management of patients, particularly where the supine posture is required.

PURPOSE: Longitudinal respiratory symptoms are rarely studied in occupational epidemiology. We investigated dyspnea change over time and predictors of change over time using two longitudinal modeling techniques, a semi-parametric group-based approach (SAS((R)) Proc Traj) and a generalized linear mixed model (SAS((R)) Proc Glimmix), and compared the two techniques for use in longitudinal studies of respiratory symptoms. METHODS: Data were previously collected from a lung health surveillance study of marine transportation workers. Subjects were seen two to four times over 12 years (1987-1999). At each visit the American Thoracic Society questionnaire was administered and lung function was tested. The semi-parametric group-based model and the generalized linear mixed model were applied to the data. RESULTS: The group-based trajectory model supported two groups of dyspnea change over time. Group 1 (73%) had a steady low-level probability of reporting dyspnea over follow-up, while Group 2 (27%) had an increasing probability of reporting dyspnea over follow-up. The generalized linear mixed model (random intercept) estimated that the probability of reporting dyspnea was increasing over time in the population. Current smoking, female sex, lower lung function and older age were associated with increased probability of reporting dyspnea in both models. CONCLUSIONS: Results from both models indicate that the probability of reporting dyspnea was increasing over time in this occupational cohort. The group-based model is capable of identifying multiple patterns of linear and non-linear change while the generalized linear mixed model is preferable when the population mean change (linear) is of interest. Both approaches were able to identify similar characteristics associated with longitudinal dyspnea symptoms.

ABSTRACT: BACKGROUND: To investigate the correlation and level of agreement between end-tidal carbon dioxide (EtCO2) and blood gas pCO2 in non-intubated children with moderate to severe respiratory distress. METHODS: Retrospective study of patients admitted to an intermediate care unit (InCU) at a tertiary care center over a 20-month period with moderate to severe respiratory distress secondary to asthma, bronchiolitis, or pneumonia. Patients with venous pCO2 (vpCO2) and EtCO2 measurements within 10 minutes of each other were eligible for inclusion. Patients with cardiac disease, chronic pulmonary disease, poor tissue perfusion, or metabolic abnormalities were excluded. RESULTS: Eighty EtCO2-vpCO2 paired values were available from 62 patients. The mean +/-SD for EtCO2 and vpCO2 was 35.7 +/-10.1 mmHg and 39.4 +/-10.9 mmHg respectively. EtCO2 and vpCO2 values were highly correlated (r=0.90, p<0.0001). The correlations for asthma, bronchiolitis and pneumonia were 0.74 (p <0.0001), 0.83 (p=0.0002) and 0.98 (p<0.0001) respectively. The mean bias +/-SD between EtCO2 and vpCO2 was -3.68 +/-4.70 mmHg. The 95% level of agreement ranged from -12.88 to +5.53 mmHg. EtCO2 was found to be more accurate when vpCO2 was 35 mmHg or lower. CONCLUSIONS: EtCO2 is correlated highly with vpCO2 in non-intubated pediatric patients with moderate to severe respiratory distress across respiratory illnesses. Although the level of agreement between the two methods precludes the overall replacement of blood gas evaluation, EtCO2 monitoring remains a useful, continuous, non-invasive measure in the management of non-intubated children with moderate to severe respiratory distress.