The obese patient in the ICU

Population pharmacokinetic analysis of TQ-B3203 following intravenous administration of TQ-B3203 liposome injection in Chinese patients with advanced solid tumors

Background: TQ-B3203 is a novel topoisomerase I inhibitor currently in development for the treatment of advanced solid tumors. Great differences in pharmacokinetic characteristics were found among individuals according to the phase I clinical trial following intravenous administration of TQ-B3203 liposome injection (TLI) in Chinese patients with advanced solid tumors. Thus, it is significant to establish a population pharmacokinetic model to find the key factors and recognize their effect on pharmacokinetic parameters in order to guide individualized administration. Methods: Non-linear mixed effect models were developed using the plasma concentrations obtained from the phase I clinical trial by implementing the Phoenix NLME program. Covariates that may be related to pharmacokinetics were screened using stepwise methods. The final model was validated by goodness-of-fit plots, visual predictive check, non-parametric bootstrap and a test of normalized prediction distribution errors. Results: A three-compartment model with first-order elimination was selected as the best structural model to describe TQ-B3203 disposition adequately. Direct bilirubin (DBIL) and body mass index (BMI) were the two most influential factors on clearance, while lean body weight (LBW) was considered to affect the apparent distribution volume of the central compartment. The population estimations of clearance and central volume were typical at 3.97 L/h and 4.81 L, respectively. Model-based simulations indicated that LBW had a great impact on C_max, BMI exerted a considerable influence on AUC_0-t, and the significance of DBIL on both AUC_0-t and C_max was similarly excellent. Conclusion: The first robust population pharmacokinetic model of TQ-B3203 was successfully generated following intravenous administration of TLI in Chinese patients with advanced solid tumors. BMI, LBW and DBIL were significant covariates that affected the pharmacokinetics of TQ-B3203. This model could provide references for the dose regimen in the future study of TLI.

Multimorbidity and Critical Care Neurosurgery: Minimizing Major Perioperative Cardiopulmonary Complications

With increasing prevalence of chronic diseases, multimorbid patients have become commonplace in the neurosurgical intensive care unit (neuro-ICU), offering unique management challenges. By reducing physiological reserve and interacting with one another, chronic comorbidities pose a greatly enhanced risk of major postoperative medical complications, especially cardiopulmonary complications, which ultimately exert a negative impact on neurosurgical outcomes. These premises underscore the importance of perioperative optimization, in turn requiring a thorough preoperative risk stratification, a basic understanding of a multimorbid patient’s deranged physiology and a proper appreciation of the potential of surgery, anesthesia and neurocritical care interventions to exacerbate comorbid pathophysiologies. This knowledge enables neurosurgeons, neuroanesthesiologists and neurointensivists to function with a heightened level of vigilance in the care of these high-risk patients and can inform the perioperative neuro-ICU management with individualized strategies able to minimize the risk of untoward outcomes. This review highlights potential pitfalls in the intra- and postoperative neuro-ICU period, describes common preoperative risk stratification tools and discusses tailored perioperative ICU management strategies in multimorbid neurosurgical patients, with a special focus on approaches geared toward the minimization of postoperative cardiopulmonary complications and unplanned reintubation.

The Impact of BMI on Adult Blunt Trauma Outcomes

Traumatic injuries account for 10% of all mortalities in the United States. Globally, it is estimated that by the year 2030, 2.2 billion people will be overweight (BMI ≥ 25) and 1.1 billion people will be obese (BMI ≥ 30). Obesity is a known risk factor for suboptimal outcomes in trauma; however, the extent of this impact after blunt trauma remains to be determined. The incidence, prevalence, and mortality rates from blunt trauma by age, gender, cause, BMI, year, and geography were abstracted using datasets from 1) the Global Burden of Disease group 2) the United States Nationwide Inpatient Sample databank 3) two regional Level II trauma centers. Statistical analyses, correlations, and comparisons were made on a global, national, and state level using these databases to determine the impact of BMI on blunt trauma. The incidence of blunt trauma secondary to falls increased at global, national, and state levels during our study period from 1990 to 2015, with a corresponding increase in BMI at all levels ( P < 0.05). Mortality due to fall injuries was higher in obese patients at all levels ( P < 0.05). Analysis from Nationwide Inpatient Sample database demonstrated higher mortality rates for obese patients nationally, both after motor vehicle collisions and mechanical falls ( P < 0.05). In obese and nonobese patients, regional data demonstrated a higher blunt trauma mortality rate of 2.4% versus 1.2%, respectively ( P < 0.05) and a longer hospital length of stay of 4.13 versus 3.26 days, respectively ( P = 0.018). The obesity rate and incidence of blunt trauma secondary to falls are increasing, with a higher mortality rate and longer length of stay in obese blunt trauma patients.

Changes in total body surface area and the distribution of skin surfaces in relation to body mass index

BACKGROUND

A correct estimation of total burn surface area is important since it is used for determining fluid resuscitation volumes, nutritional estimates and hospital admission criteria. Wallace's rule of nines is the most commonly used methods for this purpose. However, fat distribution is non-uniform and the total body surface area changes with obesity. The aim of this study was to determine if the rule of nines applies to all body mass index groups.

METHODS

A total of 217 individuals were included in the study. The patients were divided into 4 groups according to their BMI (18.5-25kg/m² (60 persons)), 25-29.9kg/m² (61 individuals)), 30-34.9kg/m² (55 persons)), >35kg/m² (41 persons)). Each patient underwent a complete duel-energy X-ray absorptiometry body scan to determine the surface area (cm²) of the various regions of the body.

RESULTS

We found no statistically significant variations between the Wallace body percentage distributions and our results in the men for all BMI ranges (head p=0.331, arms p=0.861, legs p=0.282, trunk p=0.696). In contrast, among women we found a statistically significant change in body surface area percentage distribution between the BMI groups and specific body regions (head p=0.000, legs p=0.000 and trunk p=0.001).

CONCLUSION

The Wallace rule of nines is a quick and acceptable method for estimating the total burn surface area percentage in men of all BMI ranges. However, for women, a more accurate method of burn area estimation is required as proposed by our BMI adjusted charts.

Association of Obesity with Increased Mortality in the Critically Ill Patient

The impact of obesity on critical care outcomes has been an issue for debate in the literature. Variable data and conflicting results have been reported. The purpose of our study is to examine the impact of obesity on the outcome of patients admitted to a tertiary closed Intensive Care Unit (ICU) in Saudi Arabia.

Data was obtained from a prospectively collected database from September 2001 to May 2004. Patients younger than 18, those with burns, brain death and readmissions were excluded. The study population was stratified into six groups according to their Body Mass Index (BMI). Primary endpoints were ICU and hospital mortality, duration of mechanical ventilation and ICU length of stay.

A total of 1835 patients were included in the analysis. Baseline characteristics were similar among the six groups including severity of illness scores, reflected by Acute Physiology and Chronic Health Evaluation II (APACHE II) scores. The ICU mortality was not statistically different among the groups. Hospital mortality was lower in patients with BMI 35–39.9 kg/m2 and BMI >40 kg/m2 compared to those with BMI 18.5–24.9 kg/m2. Multivariate analysis showed that a BMI >40 kg/m2 was an independent predictor of lower hospital mortality (odds ratio 0.51, 95% confidence interval 0.28–0.92, P 0.025) after adjustment for other confounding factors.

In conclusion, mortality of obese critically ill patients was not higher than patients with normal weight. In fact, the hospital mortality was lower for patients with BMI >40 kg/m2 compared to the normal BMI group despite similar severity of illness. Obesity might have a protective effect, although further studies are needed to substantiate this finding.

Optimization of Mechanical Ventilation in a 31-Year-Old Morbidly Obese Man With Refractory Hypoxemia

Morbidly obese, critically ill patients are prone to develop hypoxemic respiratory failure and ventilator dependency. The best method for recruiting the lungs of these patients and keeping alveoli open without causing injury remains unclear. We present the case of a 31-year-old patient with severe refractory hypoxemia reversed by lung recruitment maneuvers and subsequent application of positive end-expiratory pressure (PEEP) at a level determined by a decremental PEEP trial. The patient was extubated at a high PEEP level of 22 cm H2O followed by noninvasive ventilatory support after extubation. This case suggests that a recruitment maneuver followed by PEEP titration is necessary in obese patients for optimizing mechanical ventilation. Extubation to noninvasive ventilatory support with the identified optimal PEEP may decrease an inappropriate increased work of breathing and the risk of reintubation.

Effect of Parenteral Nutrition on Nutrition Status After Bariatric Surgery for Morbid Obesity

BACKGROUND

To evaluate the influence of nutrition support (parenteral nutrition [PN] vs no parenteral nutrition [nPN]) on nutrition outcome, complications, and hospital stay after bariatric surgery (BS).

METHODS

Sixty-seven consecutive BS patients (17 gastric bypass and 50 biliopancreatic diversion). The first 38 received PN and the next 29 did not (nPN) during the fasting postoperative (PO) period. In both groups, after fasting, a progressive oral diet was introduced. Data related to nutrition status, perioperative complications, and postsurgical hospital stay were compared.

RESULTS

Sixty-seven patients (58 women), mean age 39.4 +/- 11.0 years, body mass index (BMI) 50.7 +/- 6.1 kg/m(2), were included. Thirty-eight patients received PN during 8.7 +/- 2.6 days. Ingestion was initiated at a median 8 PO days in PN vs 6.5 PO days in nPN (p < .04). No significant differences between groups were found in age, final fasting serum albumin (SA), and 30 days postoperative SA, with a similar weight loss. Nonsignificant differences were found in non-catheter-related infectious complications, being mainly urinary tract infections. Catheter-related infections were present in 21.1% in the PN group and 13.8% in the nPN (p = .33). Median hospital stay after surgery was 14 +/- 10 days in PN and 12 +/- 10 days in nPN (p = .003).

CONCLUSIONS

(1) Nutrition status after BS PO and 30 days postsurgery was no different between PN and nPN. (2) Postsurgery hospital stay was significantly decreased in the nPN group, without a greater incidence of complications. (3) According to nutrition outcome, PN seems unnecessary at the perioperative period in BS unless there are other postsurgical complications.

Population Pharmacokinetics and Pharmacodynamics Modelling of Dilmapimod in Severe Trauma Subjects at Risk for Acute Respiratory Distress Syndrome

Introduction

Dilmapimod is a potent p38 mitogen-activated protein kinase (MAPK) inhibitor and was investigated in a study (NCT00996840) for its anti-inflammatory effect in non-head injury trauma patients at risk for developing acute respiratory distress syndrome (ARDS). The purpose of this paper is to present the details of the development of a population pharmacokinetic (PK) model, an empirical population placebo response model, and the exploration of a PK/pharmacodynamic (PD) model of dilmapimod.

Methods

A population PK model was developed to characterise the PK profile of dilmapimod in this patient population; the potential effect of available covariates on the PK of dilmapimod was evaluated. An empirical population placebo response model was conducted, and a population PK/PD model was explored to evaluate the relationship between dilmapimod concentration and C-reactive protein (CRP) (a systemic biomarker of p38 inhibition). All analyses were performed using NONMEM software.

Results

Following intravenous dosing, dilmapimod was quickly distributed to peripheral compartments and then slowly eliminated. The plasma concentration of dilmapimod was adequately described by a three-compartment model. It increased approximately proportionally to the increase in dose. The population clearance (CL) parameter value was 35.87 L/h, and the steady-state volume of distribution (Vss) [sum of the volume of distribution of the central compartment (Vc) and of the peripheral compartments V2 and V3] was 160 L. The effect of body mass index (BMI) on CL and inter-compartment clearance (Q2) was found statistically significant, with an increase in BMI of 1 kg/m² resulting in a 1.79 L/h and 0.52 L/h increase in CL and Q2, respectively. The CRP profile post injury was adequately described by an indirect response model, with a sharp increase in the CRP levels following injury, followed by them slowly diminishing. Data exploration indicated potential drug effects of dilmapimod on inhibiting the production of CRP levels; however, the current small dataset did not show a statistically significant improvement in the PK/PD modelling.

Conclusion

The population PK modelling adequately evaluated the dilmapimod plasma concentration–time profiles in severe trauma subjects at risk for ARDS, and BMI was found to be a significant covariate in the PK model. An indirect response model was adequate to describe the production and degradation of CRP levels in these subjects.

Outcome of Morbid Obesity in the Intensive Care Unit

This was a retrospective chart review of consecutive obese patients admitted to the medical intensive care unit. Patients were divided into 2 groups: mild to moderately obese (group 1, body mass index =30-40 kg/m2) and morbidly obese (group 2, body mass index >40 kg/m2). Acute Physiology and Chronic Health Evaluation II scores were not significantly different between the 2 groups. Morbidly obese patients (group 2) had higher rates of mortality and nursing home admission. They also showed higher rates of intensive care unit complications including sepsis, nosocomial pneumonia, acute respiratory distress syndrome, catheter infection, tracheostomy, and acute renal failure. Their median length of mechanical ventilation was longer (2 days, range 2-12 vs 9 days, range 1-37, P = .009). In a logistic regression analysis, morbid obesity remained a significant predictor of death or disposition to nursing home even after controlling for age ( P = .019, odds ratio = 7.60, 95% confidence interval = 1.39-41.6). Morbidly obese patients (body mass index >40 kg/m2) admitted to intensive care units have higher rates of mortality, nursing home admission, and intensive care unit complications and have longer stays in the intensive care unit and time on mechanical ventilation.

Noninvasive Ventilation in the Critically Ill Patient With Obesity Hypoventilation Syndrome: A Review

Obesity is a global epidemic that adversely affects respiratory physiology. Sleep-disordered breathing and obesity hypoventilation syndrome (OHS) are among the most common pulmonary complications related to obesity class III. Patients with OHS may present with acute hypercapnic respiratory failure (AHRF) that necessitates immediate noninvasive ventilation (NIV) or invasive ventilation and intensive care unit (ICU) monitoring. The OHS is underrecognized as a cause of AHRF. The management of mechanical ventilation in obese ICU patients is one of the most challenging problems facing respirologists, intensivists, and anesthesiologists. The treatment of AHRF in patients with OHS should aim to improve alveolar ventilation with better alveolar gas exchange, as well as maintaining a patent upper airway, which is ideally achieved through NIV. Treatment with NIV is associated with improvement in blood gases and lung mechanics and may reduce hospital admissions and morbidity. In this review, we will address 3 main issues: (1) NIV of critically ill patients with acute respiratory failure and OHS; (2) the indications for postoperative application of NIV in patients with OHS; and (3) the impact of OHS on weaning and postextubation respiratory failure. Additionally, the authors propose an algorithm for the management of obese patients with AHRF.

Drug disposition in obesity: toward evidence-based dosing

Obesity and morbid obesity are associated with many physiological changes affecting pharmacokinetics, such as increased blood volume, cardiac output, splanchnic blood flow, and hepatic blood flow. In obesity, drug absorption appears unaltered, although recent evidence suggests that this conclusion may be premature. Volume of distribution may vary largely, but the magnitude and direction of changes seem difficult to predict, with extrapolation on the basis of total body weight being the best approach to date. Changes in clearance may be smaller than in distribution, whereas there is growing evidence that the influence of obesity on clearance can be predicted on the basis of reported changes in the metabolic or elimination pathways involved. For obese children, we propose two methods to distinguish between developmental and obesity-related changes. Future research should focus on the characterization of physiological concepts to predict the optimal dose for each drug in the obese population.

Respiratory management of the obese patient undergoing surgery

As a reflection of the increasing global incidence of obesity, there has been a corresponding rise in the proportion of obese patients undergoing major surgery. This review reports the physiological effect of these changes in body composition on the respiratory system and discusses the clinical approach required to maximize safety and minimize the risk to the patient. The changes in respiratory system compliance and lung volumes, which can adversely affect pulmonary gas exchange, combined with upper airways obstruction and sleep-disordered breathing need to be considered carefully in the peri-operative period. Indeed, these challenges in the obese patient have led to a clear focus on the clinical management strategy and development of peri-operative pathways, including pre-operative risk assessment, patient positioning at induction and under anesthesia, modified approach to intraoperative ventilation and the peri-operative use of non-invasive ventilation (NIV) and continuous positive airways pressure.

Nutritional care of the obese adult burn patient: a U.K. Survey and literature review

Obesity is an emerging healthcare problem and affects an increasing number of burn patients worldwide. An email survey questionnaire was constructed and distributed among the 16 U.K. burn services providing adult inpatient facilities to investigate nutritional practices in obese thermally injured patients. Responses received from all dieticians invited to participate in the study were analyzed, and a relevant literature review of key aspects of nutritional care is presented. The majority of services believe that obese patients warrant a different nutritional approach with specific emphasis to avoid overfeeding. The most common algebraic formulae used to calculate calorific requirements include the Schofield, Henry, and modified Penn State equations. Indirect calorimetry despite being considered the "criterion standard" tool to calculate energy requirements is not currently used by any of the U.K. burn services. Gastric/enteral nutrition is initiated within 24 hours of admission in the services surveyed, and a variety of different practices were noted in terms of fasting protocols before procedures requiring general anesthesia/sedation. Hypocaloric regimens for obese patients are not supported by the majority of U.K. facilities, given the limited evidence base supporting their use. The results of this survey outline the wide diversity of dietetic practices adopted in the care of obese burn patients and reveal the need for further study to determine optimal nutritional strategies.

Nutrition and care considerations in the overweight and obese population within the critical care setting

Nutrition and care considerations in the overweight and obese population within the critical care setting are multifaceted. Patients requiring critical care have specialized care management needs that often times challenge health care providers. When patients are obese, this further complicates the physiologic aspects of healing, thus creating challenges to meeting both the nutritional needs of the individual and hampering treatment. This article reviews the care considerations, physiology of bariatric patients, and challenges of providing safe and quality care, including current evidence-based practice strategies developed to provide optimal support for obese patients during hospitalization and within the critical care setting.

Obesity does not increase mortality after emergency surgery

OBJECTIVE

The aim of this study is to evaluate the impact of obesity on patient outcomes after emergency surgery.

METHODS

A list of all patients undergoing emergent general surgical procedures during the 12 months ending in July 2012 was obtained from the operating room log. A chart review was performed to obtain the following data: patient characteristics (age, gender, BMI, and preexisting comorbidities), indication for surgery, and outcomes (pulmonary embolus (PE), deep venous thrombosis (DVT), respiratory failure, ICU admission, wound infection, pneumonia, and mortality). Obesity was defined as a BMI over 25. Comparisons of outcomes between obese and nonobese patients were evaluated using Fischer's exact test. Predictors of mortality were evaluated using logistic regression.

RESULTS

341 patients were identified during the study period. 202 (59%) were obese. Both groups were similar in age (48 for obese versus 47 for nonobese, P = 0.42). Obese patients had an increased incidence of diabetes, (27% versus 7%, P < 0.05), hypertension (52% versus 34%, P < 0.05), and sleep apnea (0% versus 5%, P < 0.05). There was a statistically significant increased incidence of postoperative wound infection (obese 9.9% versus nonobese 4.3%, P < 0.05) and ICU admission (obese 58% versus nonobese 42%, P = 0.01) among the obese patients. Obesity alone was not shown to be a significant risk factor for mortality.

CONCLUSIONS

A higher BMI is not an independent predictor of mortality after emergency surgery. Obese patients are at a higher risk of developing wound infections and requiring ICU admission after emergent general surgical procedure.

The impact of body mass index on the development of systemic inflammatory response syndrome and sepsis in patients with polytrauma

PURPOSE

Obesity is a growing problem in industrial nations. Our aim was to examine how overweight patients coped with systemic inflammatory response syndrome (SIRS) after polytrauma.

METHODS

A total of 651 patients were included in this retrospective study, with an ISS ≥ 16 and age ≥ 16 years. The sample was subdivided into three groups: body mass index (BMI; all in kg/m(2))<25, BMI 25-30 and BMI>30, or low, intermediate and high BMI. The SIRS score was measured over 31 days after admission together with measurements of C-reactive protein (CRP), interleukin-6 (IL-6) and procalcitonin (PCT). Data are given as the mean ± SEM if not otherwise indicated. Kruskal-Wallis and χ(2) tests were used for statistical analysis and the significance level was set at p<.05.

RESULTS

The maximum SIRS score was reached in the low BMI-group at 3.4 ± 0.4, vs. 2.3 ± 0.1 and 2.5 ± 0.2 in the intermediate BMI-group and high BMI-group, respectively (p<.0001). However, the maximum SIRS score was reached earlier in the BMI 25-30 group at 1.8 ± 0.2 days, vs. 3.4 ± 0.4 and 2.5 ± 0.2 days in the BMI<25 and BMI>30 groups, respectively (p<.0001). The incidence of sepsis was significantly higher in the low BMI group at 46.1%, vs. 0.2% and 0% in the BMI 25-30 and BMI>30 groups, respectively (p<.0001). No significant differences in the CRP, IL-6 or PCT levels were found between groups.

CONCLUSIONS

A higher BMI seemed to be protective for these patients with polytrauma-associated inflammatory problems.

Effects of sitting position and applied positive end-expiratory pressure on respiratory mechanics of critically ill obese patients receiving mechanical ventilation*

OBJECTIVE

To evaluate the extent to which sitting position and applied positive end-expiratory pressure improve respiratory mechanics of severely obese patients under mechanical ventilation.

DESIGN

Prospective cohort study.

SETTINGS

A 15-bed ICU of a tertiary hospital.

PARTICIPANTS

Fifteen consecutive critically ill patients with a body mass index (the weight in kilograms divided by the square of the height in meters) above 35 were compared to 15 controls with body mass index less than 30.

INTERVENTIONS

Respiratory mechanics was first assessed in the supine position, at zero end-expiratory pressure, and then at positive end-expiratory pressure set at the level of auto-positive endexpiratory pressure. Second, all measures were repeated in the sitting position.

MEASUREMENTS AND MAIN RESULTS

Assessment of respiratory mechanics included plateau pressure, auto-positive end-expiratory pressure, and flow-limited volume during manual compression of the abdomen, expressed as percentage of tidal volume to evaluate expiratory flow limitation. In supine position at zero end-expiratory pressure, all critically ill obese patients demonstrated expiratory flow limitation (flow-limited volume, 59.4% [51.3-81.4%] vs 0% [0-0%] in controls; p < 0.0001) and greater auto-positive end-expiratory pressure (10 [5-12.5] vs 0.7 [0.4-1.25] cm H2O in controls; p < 0.0001). Applied positive end-expiratory pressure reverses expiratory flow limitation (flow-limited volume, 0% [0-21%] vs 59.4% [51-81.4%] at zero end-expiratory pressure; p < 0.001) in almost all the obese patients, without increasing plateau pressure (24 [19-25] vs 22 [18-24] cm H2O at zero end-expiratory pressure; p = 0.94). Sitting position not only reverses partially or completely expiratory flow limitation at zero end-expiratory pressure (flow-limited volume, 0% [0-58%] vs 59.4% [51-81.4%] in supine obese patients; p < 0.001) but also results in a significant drop in auto-positive end-expiratory pressure (1.2 [0.6-4] vs 10 [5-12.5] cm H2O in supine obese patients; p < 0.001) and plateau pressure (15.6 [14-17] vs 22 [18-24] cm H2O in supine obese patients; p < 0.001).

CONCLUSIONS

In critically ill obese patients under mechanical ventilation, sitting position constantly and significantly relieved expiratory flow limitation and auto-positive end-expiratory pressure resulting in a dramatic drop in alveolar pressures. Combining sitting position and applied positive end-expiratory pressure provides the best strategy.

ProSeal laryngeal mask airway improves oxygenation when used as a conduit prior to laryngoscope guided intubation in bariatric patients

Background:

The primary objective of this study was to compare the effect of ventilation using the ProSeal™ laryngeal mask airway (PLMA) with facemask and oropharyngeal airway (FM), prior to laryngoscopy, on arterial oxygenation in morbidly obese patients undergoing bariatric surgery.

Methods:

Forty morbidly obese patients were randomly recruited to either PLMA or FM. After pre-oxygenation (FiO₂ 1.0) in the ramp position with continuous positive airway pressure of 10 cm H₂O for 5 min, anaesthesia was induced. Following loss of jaw thrust oropharyngeal airway, the FM and PLMA were inserted. On achieving paralysis, volume control ventilation with PEEP (5 cm H₂O) was initiated. The difficulty in mask ventilation (DMV) in FM, number of attempts at PLMA and laryngoscopy were graded (Cormack and Lehane) in all patients. Time from onset of laryngoscopy to endotracheal tube confirmation was recorded. Hypoxia was defined as mild (SpO₂ ≤95%), moderate (SpO₂ ≤90%) and severe (SpO₂ ≤85%).

Results:

Significant rise in pO₂ was observed within both groups (P=0.001), and this was significantly higher in the PLMA (P=0.0001) when compared between the groups. SpO₂ ≥ 90% (P=0.018) was seen in 19/20 (95%) patients in PLMA and 13/20 (65%) in FM at confirmation of tracheal tube. A strong association was found between DMV and Cormack Lehane in the FM group and with number of attempts in the PLMA group. No adverse events were observed.

Conclusion:

ProSeal™ laryngeal mask airway as conduit prior to laryngoscopy in morbidly obese patients seems effective in increasing oxygen reserves, and can be suggested as a routine airway management technique when managing the airway in the morbidly obese.

Obesity significantly increases the difficulty of patient management in the emergency department

OBJECTIVE

To determine which aspects of ED management are adversely affected by patient obesity, to determine the level of obesity above which management is made more difficult and to make recommendations on how these effects might be mitigated.

METHODS

This was a cross-sectional survey of patients and the staff caring for them in a single ED. Doctors, nurses and radiographers managing consecutive patients, during a range of enrolment periods, completed a self-administered questionnaire. Each was asked to record how the level of their patient's obesity increased the difficulty of specific management items, using a Likert scale. Staff also provided recommendations to mitigate the effects of obesity for each patient, if applicable. For each management item, body mass index (BMI) and management difficulty were correlated (Spearman's rank correlation).

RESULTS

Seven hundred and fifty patients and their ED carers were enrolled. Patient BMI was positively correlated with all aspects of ED clinical management examined (correlation coefficient range 0.28-0.57, P < 0.001). BMI most strongly correlated with difficulty in finding anatomical landmarks, venous pressure measurement, physical examination, patient positioning and procedures generally, especially cannulation and venipuncture (coefficient > 0.5, P < 0.001). Doctors reported more difficulties than nurses and radiographers. Generally, management difficulty did not increase until the BMI was in the obese or morbidly obese range. Most staff recommendations related to issues of patient mobility including equipment, staffing and bariatric devices.

CONCLUSION

Patient obesity significantly increases the difficulty of ED patient management. Staff recommendations to mitigate these effects were few but may inform changes in ED practice.

Being overweight or obese is associated with decreased mortality in critically ill patients: a retrospective analysis of a large regional Italian multicenter cohort

PURPOSE

To describe the epidemiology of obesity in a large cohort of intensive care unit (ICU) patients and study its impact on outcomes.

METHODS

All 3902 patients admitted to one of 24 ICUs in the Piedmont region of Italy from April 3 to September 29, 2006, were included in this retrospective analysis of data from a prospective, multicenter study.

RESULTS

Mean body mass index (BMI) was 26.0 ± 5.4 kg/m(2): 32.8% of patients had a normal BMI, 2.6% were underweight, 45.1% overweight, 16.5% obese, and 2.9% morbidly obese. ICU mortality was significantly (P < .05) lower in overweight (18.8%) and obese (17.5%) patients than in those of normal BMI (22%). In multivariate logistic regression analysis, being overweight (OR = 0.73; 95%CI: 0.58-0.91, P = .007) or obese (OR = 0.62; 95%CI: 50.45-0.85, P = .003) was associated with a reduced risk of ICU death. Being morbidly obese was independently associated with an increased risk of death in elective surgery patients whereas being underweight was independently associated with an increased risk of death in patients admitted for short-term monitoring and after elective surgery.

CONCLUSIONS

In this cohort, overweight and obese patients had a reduced risk of ICU death. Being underweight or morbidly obese was associated with an increased risk of death in some subgroups of patients.

The impact of body mass index on the physiology of patients with polytrauma

PURPOSE

Obesity is a growing problem in industrial nations. The aim was to test the hypothesis that overweight patients face early physiologic impairment.

METHODS

A total of 651 patients were included in this retrospective study, with an injury severity score greater than 16 and 16 years or older. The sample was subdivided into 3 groups: body mass index (BMI) less than 25 kg/m(2), BMI of 25 to 30 kg/m(2), and BMI greater than 30 kg/m(2). Physiologic scores-Murray, Goris, Marshall and Sequential Organ Failure Assessment scores-were analyzed at admission and at the day of their maximum. Analysis of variance and χ(2) tests were used, and the significance level was set at P < .05.

RESULTS

All 4 scores showed significant differences at their maxima according to the 3 BMI groups, respectively: Murray score (P < .001), Goris score (P < .05), Marshall score (P < .001), and Sequential Organ Failure Assessment score (P <.05). The injury severity score values of the 3 groups at admission were 27.6 ± 12.0, 29.6 ± 13.2, and 25.3 ± 9.2, respectively (P < .05). The overall mortality rates in the 3 groups were 15.1%, 21.0%, and 20%, respectively (P < .001).

CONCLUSIONS

Anticipating BMI-specific critical trauma problems will become mandatory for effective polytrauma treatment in industrialized nations given their increasing prevalence of obesity.

Clinical and critical care concerns in severely ill obese patient

The incidence of obesity has acquired an epidemic proportion throughout the globe. As a result, increasing number of obese patients is being presented to critical care units for various indications. The attending intensivist has to face numerous challenges during management of such patients. Almost all the organ systems are affected by the impact of obesity either directly or indirectly. The degree of obesity and its prolong duration are the main factors which determine the harmful effect of obesity on human body. The present article reviews few of the important clinical and critical care concerns in critically ill obese patients.

Impact of obesity on drug metabolism and elimination in adults and children

The prevalence of obesity in adults and children is rapidly increasing across the world. Several general (patho)physiological alterations associated with obesity have been described, but the specific impact of these alterations on drug metabolism and elimination and its consequences for drug dosing remains largely unknown. In order to broaden our knowledge of this area, we have reviewed and summarized clinical studies that reported clearance values of drugs in both obese and non-obese patients. Studies were classified according to their most important metabolic or elimination pathway. This resulted in a structured review of the impact of obesity on metabolic and elimination processes, including phase I metabolism, phase II metabolism, liver blood flow, glomerular filtration and tubular processes. This literature study shows that the influence of obesity on drug metabolism and elimination greatly differs per specific metabolic or elimination pathway. Clearance of cytochrome P450 (CYP) 3A4 substrates is lower in obese as compared with non-obese patients. In contrast, clearance of drugs primarily metabolized by uridine diphosphate glucuronosyltransferase (UGT), glomerular filtration and/or tubular-mediated mechanisms, xanthine oxidase, N-acetyltransferase or CYP2E1 appears higher in obese versus non-obese patients. Additionally, in obese patients, trends indicating higher clearance values were seen for drugs metabolized via CYP1A2, CYP2C9, CYP2C19 and CYP2D6, while studies on high-extraction-ratio drugs showed somewhat inconclusive results. Very limited information is available in obese children, which prevents a direct comparison between data obtained in obese children and obese adults. Future clinical studies, especially in children, adolescents and morbidly obese individuals, are needed to extend our knowledge in this clinically important area of adult and paediatric clinical pharmacology.

Obesity and respiratory infections: does excess adiposity weigh down host defense?

The number of overweight and obese individuals has dramatically increased in the US and other developed nations during the past 30 years. While type II diabetes and cardiovascular disease are well recognized co-morbid conditions associated with obesity, recent reports have demonstrated a greater severity of illness in obese patients due to influenza during the 2009 H1N1 pandemic. Consistent with these reports, diet-induced obesity has been shown to impair anti-viral host defense in murine models of influenza infection. However, the impact of obesity on the risk of community-acquired and nosocomial pneumonia in human patients is not clear. Relatively few studies have evaluated the influence of diet-induced obesity in murine models of bacterial infections of the respiratory tract. Obese leptin deficient humans and leptin and leptin-receptor deficient mice exhibit greater susceptibility to respiratory infections suggesting a requirement for leptin in the pulmonary innate and adaptive immune response to infection. In contrast to these studies, we have observed that obese leptin receptor signaling mutant mice are resistant to pneumococcal pneumonia highlighting the complex interaction between leptin receptor signaling and immune function. Given the increased prevalence of obesity and poor responsiveness of obese individuals to vaccination against influenza, the development of novel immunization strategies for this population is warranted. Additional clinical and animal studies are needed to clarify the relationship between increased adiposity and susceptibility to community-acquired and nosocomial pneumonia.

The impact of BMI on polytrauma outcome

BACKGROUND

Varying results have been reported concerning the effect of body mass index (BMI) on polytrauma outcome. Although most studies focus on obesity and its associated preexisting medical diseases as a predictor for increased mortality rates, there is evidence that polytrauma patients with underweight also face an inferior outcome.

METHODS

Records of 5766 trauma patients (minimum 18 years of age, Injury Severity Score ≥ 16, treated from 2004 to 2008) documented in the Trauma Registry of the German Society for Trauma Surgery were subclassified into 4 BMI groups and analysed to assess the impact of BMI on polytrauma outcome.

RESULTS

Underweight (BMI Group I) as well as obesity (BMI Group IV) in polytraumatized patients are associated with significantly increased mortality by multivariate logistic regression analysis with hospital mortality as the target variable (adjusted odds ratio for BMI Group I, 2.1 (95% CI 1.2-3.8, p = 0.015); for BMI Group IV, 1.6 (95% CI 1.1-2.3, p = 0.009)). Simple overweight (BMI Group III) does not qualify as a predictor for increased mortality (odds ratio 1.0; 95% CI 0.8-1.3).

CONCLUSIONS

There is a significant correlation between obesity, underweight, and increased mortality in polytraumatized patients. Efforts to promote optimal body weight may reduce not only the risk of chronic diseases but also the risk of polytrauma mortality amongst obese and underweight individuals.

A review of the methods, interpretation, and limitations of the urine drug screen

Toxicology screens are used to detect the presence of prescription, nonprescription, or illicit substances. These tests are used in emergency situations to detect intentional or accidental overdose, to monitor drug dependency, and to screen for medical or legal purposes. An initial immunoassay reports qualitative results based on established cut-off concentrations. As a screening test, the initial immunoassay is less sensitive and therefore must be interpreted in the context of confounding variables such as the testing method, the substance being screened, and patient-specific characteristics. Either gas chromatography or high-performance liquid chromatography can be used to confirm positive results.

The impact of obesity on critical care resource use and outcomes

Obese patients in the ICU present unique challenges to the health care team and specific challenges to nurses. This article reviews the science and art of resource use for obese patients in the ICU. Staff nurses and advanced practice nurses can make important contributions in evaluating optimal resource use and improving outcomes in this population of vulnerable patients.

Pulmonary aspects of obesity in critical care

Critically ill obese patients have many challenging pulmonary problems. The first key is to understand pathophysiology in the pulmonary system related to obesity. Second, it is important to identify the altered physical assessments and diagnostics that occur because of the pulmonary pathophysiology of obesity. Lastly, one should be aware of medical and nursing intervention options that treat symptoms or pulmonary problems of obesity. This article summarizes pulmonary issues related to obesity in critical care.

Nutrition in critically ill obese patients

Critically ill obese patients require timely nutrition in the intensive care unit. Hypocaloric, high protein nutritional feeding might have a role in critically ill obese patients. Although critically ill obese patients need special medical and nutritional care as do nonobese patients in the ICU, there are some differences in the literature about the initiation, routes, and nature of nutritional support. This article reviews the norms of nutritional care among critically ill obese patients and the differences between these patients and those with a normal BMI.

Provision of nutritional support to those experiencing complications following bariatric surgery

This review details the practicalities of providing nutrition support to obese patients who experience complications following bariatric surgery and highlights some of the nutritional challenges encountered by this group of patients. Bariatric surgery to treat morbid obesity has significantly increased internationally over the past decade with hospital admissions rising annually. The gastric bypass is currently the most commonly performed procedure. The complication rate can be up to 16%, with a considerable proportion having nutritional implications. The treatment can involve avoidance of oral diet and nutrition support, i.e. enteral or parenteral nutrition. Opposition to nutrition support can be encountered. It is useful to clarify the aims of nutrition support, these being: the avoidance of overfeeding and its consequences, preservation of lean body mass and promotion of healing. Evidence suggests that hypoenergic nutrition is not harmful and may actually be beneficial. There is a lack of consensus regarding the optimum method to predict the nutritional requirements in the obese acutely unwell patient. The literature suggests that the predicted equations are fairly accurate compared to measured energy expenditure in free living obese patients before and after bariatric surgery. However, these findings cannot be directly applied to those obese patients experiencing complications of bariatric surgery, who will be acutely unwell exhibiting inflammatory response. It is therefore necessary to refer to the literature on energy expenditure in hospitalized obese patients, to help guide practice. More research examining the energy and protein requirements of obese patients needing nutrition support following bariatric surgery is urgently required.

Mortality, morbidity and special issues of obese ICU patients

Obesity is on the advance in western industrialised countries and is therefore increasingly relevant also to intensive care medicine. In contrast to the common prejudice that obese patients probably have a higher ICU mortality than lean patients, convincing meta-analyses have revealed that this is not the case. Nevertheless, obese ICU patients are challenging. Especially mechanic ventilation has to be addressed: besides obesity-related anatomical problems that may complicate intubation, obstructive sleep apnoea, obesity hypoventilation syndrome and increased intra-abdominal pressure are of major relevance concerning ventilation, weaning and successful extubation. Also the risk of infections is increased in obese ICU patients, although this does not seem to increase the risk of sepsis. Nevertheless, the interplay of obesity and sepsis is a fascinating field in that adipous tissue is not just a passive reservoir of energy but an active endocrine and immunomodulating organ. However, the way of how adipokines interact with inflammation and coagulation in sepsis has yet to be clarified.

Perioperative management of obese patients

Obesity is a metabolic disease that is on the increase all over the world. Up to 35% of the population in North America and 15-20% in Europe can be considered obese. Since these patients are characterised by several systemic physiopathological alterations, the perioperative management may present some problems, mainly related to their respiratory system. Body mass is an important determinant of respiratory function before and during anaesthesia not only in morbidly but also in moderately obese patients. These can manifest as (a) reduced lung volume with increased atelectasis; (b)derangements in respiratory system, lung and chest wall compliance and increased resistance; and (c) moderate to severe hypoxaemia. These physiological alterations are more marked in obese patients with hypercapnic syndrome or obstructive sleep apnoea syndrome. The suggested perioperative ventilation management includes (a) awake and/or facilitated endotracheal intubation by using a video-laryngoscope; (b) tidal volume of 6-10 ml kg(-1) ideal body weight, increasing respiratory rate to maintain physiological PaCO2, while avoiding intrinsic positive end-expiratory pressure (PEEPi); and (c) a recruitment manoeuvre (35-55 cmH2O for 6 s) followed by the application of an end-expiratory pressure (PEEP) of 10 cmH2O. The recruitment manoeuvre should always be performed only when a volemic and haemodynamic stabilisation is reached after induction of anaesthesia. In the postoperative period, beach chair position, aggressive physiotherapy, noninvasive respiratory support and short-term recovery in intermediate critical care units with care of fluid management and pain may be useful to reduce pulmonary complications.

Emergency department management of the airway in obese adults

Airway management in obese adults can be challenging, and much of the literature on this subject focuses on elective surgical cases, rather than acutely ill patients. In this article, we review the emergency department evaluation of the airway in obesity, discussing anatomy, physiology, and pharmacology. In addition, we describe techniques and devices used to improve intubating conditions in the obese patient. After our review of the relevant literature, we conclude that research in this particular area of acute care remains in its infancy.

Clinical applications of pulse transit time in paediatric critical care

A simple and non-invasive technique, termed pulse transit time (PTT), has shown its potential in long-term investigations such as respiratory sleep studies and cardiovascular studies. Based on these findings, the PTT technique shows relevance for continuous haemodynamic monitoring in critical care. The objective of this review is to understand the potential, applications and limitations of PTT in this clinical setting. Present non-invasive haemodynamic monitoring methods such as automated oscillometric blood pressure (BP) and auscultatory techniques have their known limitations. They tend to underestimate systolic BP while overestimating diastolic BP. Due to the periodic increase in cuff pressure cycles during data acquisition, these techniques may cause much discomfort in elderly geriatric patients, or lessen the cooperation of younger paediatric patients. Thus, there can be adverse effects on therapeutic decisions and possibly clinical outcomes. Documented evidences have indicated that changes observed in PTT are inversely correlated to the corresponding BP changes. In critical care, a simple and accommodating technique like PTT may be useful in providing better comfort for patients during extended monitoring. Being a semi-quantitative measure, blanket recommendations for its utility can then become possible. The basic instrumentations needed are often part of standard critical care monitoring system. Furthermore, PTT also has the potential to monitor the often tachypnoeic respiratory dependent BP changes seen in small infants during critical care.

ESPEN Guidelines on Parenteral Nutrition: pancreas

Assessment of the severity of acute pancreatitis (AP), together with the patient's nutritional status is crucial in the decision making process that determines the need for artificial nutrition. Both should be done on admission and at frequent intervals thereafter. The indication for nutritional support in AP is actual or anticipated inadequate oral intake for 5-7 days. This period may be shorter in those with pre-existing malnutrition. Substrate metabolism in severe AP is similar to that in severe sepsis or trauma. Parenteral amino acids, glucose and lipid infusion do not affect pancreatic secretion and function. If lipids are administered, serum triglycerides must be monitored regularly. The use of intravenous lipids as part of parenteral nutrition (PN) is safe and feasible when hypertriglyceridemia is avoided. PN is indicated only in those patients who are unable to tolerate targeted requirements by the enteral route. As rates of EN tolerance increase then volumes of PN should be decreased. When PN is administered, particular attention should be given to avoid overfeeding. When PN is indicated, a parenteral glutamine supplementation should be considered. In chronic pancreatitis PN may, on rare occasions, be indicated in patients with gastric outlet obstruction secondary to duodenal stenosis or those with complex fistulation, and in occasional malnourished patients prior to surgery.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist health-care professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Obesity and respiratory diseases

Obesity is a worldwide epidemic and is known to increase the risk of cardiovascular disease, type 2 diabetes, and certain forms of cancer. In addition, obesity is now recognized as an important risk factor in the development of several respiratory diseases. Of these respiratory diseases, it has already been well established that obesity can lead to obstructive sleep apnea (OSA) and obesity-hypoventilation syndrome (OHS). More recent data suggest that the prevalence of wheezing and bronchial hyper-responsiveness, two symptoms often associated with asthma, are increased in overweight and obese individual. Indeed, epidemiological studies have reported that obesity is a risk factor for the development of asthma. Furthermore, a number of studies indicate that obesity is also associated with a higher risk of developing deep vein thrombi, pulmonary emboli, pulmonary hypertension, and pneumonia. Finally, weight reduction has been shown to be effective in improving the symptoms and severity of several respiratory diseases, including OSA and asthma. Thus, overweight and obese patients should be encouraged to lose weight to reduce their risk of developing respiratory diseases or improve the course of pre-existing conditions.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist healthcare professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.