Body Composition in Advanced Non-Small Cell Lung Cancer Treated With Immunotherapy

Importance

The association between body composition (BC) and cancer outcomes is complex and incompletely understood. Previous research in non-small-cell lung cancer (NSCLC) has been limited to small, single-institution studies and yielded promising, albeit heterogeneous, results.

Objectives

To evaluate the association of BC with oncologic outcomes in patients receiving immunotherapy for advanced or metastatic NSCLC.

Design, Setting, and Participants

This comprehensive multicohort analysis included clinical data from cohorts receiving treatment at the Dana-Farber Brigham Cancer Center (DFBCC) who received immunotherapy given alone or in combination with chemotherapy and prospectively collected data from the phase 1/2 Study 1108 and the chemotherapy arm of the phase 3 MYSTIC trial. Baseline and follow-up computed tomography (CT) scans were collected and analyzed using deep neural networks for automatic L3 slice selection and body compartment segmentation (skeletal muscle [SM], subcutaneous adipose tissue [SAT], and visceral adipose tissue). Outcomes were compared based on baseline BC measures or their change at the first follow-up scan. The data were analyzed between July 2022 and April 2023.

Main Outcomes and Measures

Hazard ratios (HRs) for the association of BC measurements with overall survival (OS) and progression-free survival (PFS).

Results

A total of 1791 patients (878 women [49%]) with NSCLC were analyzed, of whom 487 (27.2%) received chemoimmunotherapy at DFBCC (DFBCC-CIO), 825 (46.1%) received ICI monotherapy at DFBCC (DFBCC-IO), 222 (12.4%) were treated with durvalumab monotherapy on Study 1108, and 257 (14.3%) were treated with chemotherapy on MYSTIC; median (IQR) ages were 65 (58-74), 66 (57-71), 65 (26-87), and 63 (30-84) years, respectively. A loss in SM mass, as indicated by a change in the L3 SM area, was associated with worse oncologic outcome across patient groups (HR, 0.59 [95% CI, 0.43-0.81] and 0.61 [95% CI, 0.47-0.79] for OS and PFS, respectively, in DFBCC-CIO; HR, 0.74 [95% CI, 0.60-0.91] for OS in DFBCC-IO; HR, 0.46 [95% CI, 0.33-0.64] and 0.47 [95% CI, 0.34-0.64] for OS and PFS, respectively, in Study 1108; HR, 0.76 [95% CI, 0.61-0.96] for PFS in the MYSTIC trial). This association was most prominent among male patients, with a nonsignificant association among female patients in the MYSTIC trial and DFBCC-CIO cohorts on Kaplan-Meier analysis. An increase of more than 5% in SAT density, as quantified by the average CT attenuation in Hounsfield units of the SAT compartment, was associated with poorer OS in 3 patient cohorts (HR, 0.61 [95% CI, 0.43-0.86] for DFBCC-CIO; HR, 0.62 [95% CI, 0.49-0.79] for DFBCC-IO; and HR, 0.56 [95% CI, 0.40-0.77] for Study 1108). The change in SAT density was also associated with PFS for DFBCC-CIO (HR, 0.73; 95% CI, 0.54-0.97). This was primarily observed in female patients on Kaplan-Meier analysis.

Conclusions and Relevance

The results of this multicohort study suggest that loss in SM mass during systemic therapy for NSCLC is a marker of poor outcomes, especially in male patients. SAT density changes are also associated with prognosis, particularly in female patients. Automated CT-derived BC measurements should be considered in determining NSCLC prognosis.

The Effects of Bariatric Surgery on Pharmacokinetics of Drugs: a Review of Current Evidence

PURPOSE OF REVIEW

Obesity constitutes a major public health concern and has been recognized as an epidemic. To date, bariatric surgery remains the most effective way for substantial long-lasting weight loss in severe obesity. The purpose of this review is to summarize how the pharmacokinetics of drugs are affected by the most common types of bariatric surgery, i.e., Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG).

RECENT FINDINGS

Limited data are available regarding the changes in pharmacokinetics of drugs after bariatric surgery. The lack of existing guidelines may lead patients to experience drug toxicity or therapeutic undertreatment. Pharmacokinetic parameters that need to be taken into consideration postoperatively include gastric motility, gastric volume, pH, surface area, bile secretions, carrier proteins, and first-pass metabolism. For drugs with a narrow therapeutic index, other factors need to be monitored closely, including plasma drug levels, patients' clinical outcomes, and laboratory markers. Patients should be followed up frequently and treated in accordance with their response to the drug therapy. Bariatric surgery may affect the pharmacokinetics of various drugs, due to the resultant anatomical changes and the substantial weight loss. Therefore, there is a need to identify those potential changes and adjust patients' medication doses in order to achieve higher efficacy and avoid toxicity.

Comparative Analysis of Information Provided in German Adverse Drug Reaction Reports Sent by Physicians, Pharmacists and Consumers

INTRODUCTION

Adverse drug reactions (ADRs) can be reported by Health Care Professionals (HCPs; e.g., physicians, pharmacists) and non-Health Care Professionals (non-HCPs; e.g., consumers). Previous studies investigating differences between reports from HCPs and non-HCPs rarely considered the completeness of information provided. In addition, they mostly did not distinguish between physicians and pharmacists or were performed years ago. The aim of our study was to analyse and compare the completeness of information provided in reports from physicians, pharmacists and consumers from Germany in a more recent dataset.

MATERIALS AND METHODS

We analysed all spontaneous reports from Germany received between 2018 and 2021 in the ADR database EudraVigilance exclusively reported by physicians (n = 69,976), pharmacists (n = 42,396) or consumers (n = 121,144). Demographical parameters of the patients were analysed descriptively. Completeness of reports was evaluated applying an established score (vigiGrade). Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using logistic regression analysis in order to identify report, patient, drug or ADR-specific information provided more often in reports from physicians, pharmacists or consumers.

RESULTS

Within the study period the number of reports per year by physicians and pharmacists decreased steadily, while an opposite trend was observed for consumer reports. The proportion of female patients was higher in reports from pharmacists (64.4%) and consumers (64.8%) compared to those from physicians (55.3%). On average, patients in reports from pharmacists (58.7) were older compared to those from physicians (53.5) and consumers (52.6). As an example for the presence of specific information, the time to onset of the ADR could be calculated more often in consumer compared to physician (OR 1.9 [1.8-1.9]) and pharmacist reports (OR 1.7 [1.6-1.7]). In contrast, pharmacist (OR 0.5 [0.4-0.5]) and consumer (OR 0.5 [0.5-0.5]) reports included the indication of the suspected drug less often than physician reports. Physician reports on average (mean = 0.5) were slightly more complete according to the vigiGrade score compared to reports from consumers (mean = 0.4) and pharmacists (mean = 0.4).

CONCLUSION

The ADR reports from consumers were comparable with regard to the completeness score with those from physicians and pharmacists underlining their value. Differences in completeness of specific information between the reporter types were found, suggesting that a common reporting of interactions between the three reporters may further improve the completeness of ADR reports. Furthermore, stratified analysis of ADR reports per reporter type may be helpful for certain objectives in scientific research.

Pharmacokinetics of obese adults: Not only an increase in weight

Obesity is a pathophysiological state defined by a body mass index > 30 kg/m2 and characterized by an adipose tissue accumulation leading to an important weight increased. Several pathologies named comorbidities such as cardiovascular disease, type 2 diabetes and cancer make obesity the fifth cause of death in the world. Physiological changes impact the four main phases of pharmacokinetics of some drugs and leads to an inappropriate drug-dose. For absorption, the gastrointestinal transit is accelerated, and the gastric empty time is shortened, that can reduce the solubilization and absorption of some oral drugs. The drug distribution is probably the most impacted by the obesity-related changes because the fat mass (FM) increases at the expense of the lean body weight (LBW), leading to an important increase of the volume of distribution for lipophilic drugs and a low or moderately increase of this parameter for hydrophilic drugs. This modification of the distribution may require drug-dose adjustments. By various mechanisms, the metabolism and elimination of drugs are impacted by obesity and should be considered as similar or lower than that non-obese patients. To better understand the necessary drug-dose adjustments in obese patients, a narrative review of the literature was conducted to highlight the main elements to consider in the therapeutic management of adult obese patients.

Pharmacokinetics in Penguins Compared to Other Avian Species: A Review of Enrofloxacin and Voriconazole

Australasia is home to unique and endangered avian species. Drug administration to this group of animal patients for prophylaxis and treatment is challenging from a number of different perspectives. A key limitation for optimal drug dosing in birds is the lack of published pharmacokinetic studies to guide dose requirements. The aim of this review was to systematically investigate published literature on pharmacokinetics in penguin species and compare that with the pharmacokinetics of other avian species with a focus on two drugs: enrofloxacin and voriconazole. The review was conducted following PRISMA guidelines. A systematic literature search was performed in Pubmed, Embase, Scopus, and Web of Science databases. A key finding is that penguin pharmacokinetics differs from other avian species, with weight-adjusted AUC and Cmax values higher than most other avian species (e.g., for enrofloxacin, the AUC in the African penguin is 85.7 μg h/mL, which is more than double the other bird species). Doses for some avian species may be successfully extrapolated from other avian species; however, it appears important to consider factors other than just body weight (e.g., clearance mechanism and drug physicochemical characteristics). Consequently, there is an important need for robust pharmacokinetic data in wildlife species to ensure optimal therapy for this special group of patients. As part of this review, we identify key aspects that should be considered when estimating dose in species for which there is limited pharmacokinetic information available.

Therapeutic Drug Monitoring of Direct Oral Anticoagulants in Patients with Extremely Low and High Body Weight-Pilot Study

Phase III clinical trials for individual direct oral anticoagulants (DOACs) contained a limited representation of subjects with abnormal body weight, which were mostly limited to a BMI > 40 kg/m2, or body weight > 120 kg for obese subjects, and <50 kg for underweight subjects. Although low or high body weight is not a contraindication to DOACs therapy, it can significantly affect the safety and effectiveness of treatment. Due to the limited amount of clinical data on the use of DOACs in extremely abnormal weight ranges, optimal pharmacotherapy in this group of patients is a matter of controversy. The objective of this study was to evaluate the pharmacokinetics of DOAC properties in patients with abnormal body weight beyond the established cut-off points in the phase III studies for rivaroxaban, apixaban, and dabigatran. In total, 38 patients took DOACs for at least 12 months for non-valvular atrial fibrillation in 2019-2021. Blood samples were collected before the planned intake of the drug and 4 h after its administration. The determined concentrations of DOACs were statistically analyzed in relation to body weight, age, and eGFR (estimated Glomerular Filtration Rate). Among subjects taking apixaban, rivaroxaban, and dabigatran, the smallest representation of patients who achieved therapeutic concentrations were those treated with dabigatran. The population of people with abnormal body weight is a potential risk group of patients, in which some of them do not reach the therapeutic range of DOACs.

Validation of a quantitative multiplex LC-MS/MS assay of carvedilol, enalaprilat, and perindoprilat in dried blood spots from heart failure patients and its cross validation with a plasma assay

Introduction

Adherence to medication is an important determinant of outcomes in chronic diseases like heart failure. Drug assays provide objective adherence biomarkers. Dried blood spots (DBS) are appealing samples for drug assays due to less demanding transportation and storage requirements.

Objectives

To analytically validate a LC-MS/MS method for the simultaneous quantification of carvedilol, enalaprilat, and perindoprilat in DBS and evaluate the feasibility of using the method as an adherence determining assay. To validate the assay further clinically by establishing correlation and agreement between plasma and DBS samples from a pharmacokinetic pilot study.

Methods

The method was validated over a concentration range of 1.00-200 ng/mL according to FDA guidelines. Adherence tracking ability of the assay was evaluated using a pharmacokinetic pilot study. Correlation and agreement were evaluated through Deming regression and Bland-Altman analysis, respectively.

Results

Accuracy, precision, selectivity, and sensitivity were proven with complete and reproducible extraction recovery at all concentrations tested. Stability of the analytes in the matrix and throughout sample processing was proven. The full range of concentrations of the pharmacokinetic pilot study could be quantified for enalaprilat, but not for carvedilol and perindoprilat. The difference between the observed and calculated plasma concentrations was less than 20 % of their mean for >67 % of samples for all analytes.

Conclusions

The assay is suitable as a screening tool for carvedilol and perindoprilat, while suitable as an adherence determining assay for enalaprilat. Equivalence between observed and predicted plasma concentrations proves DBS and plasma concentrations can be used interchangeably.

Concerns regarding tablet splitting: a systematic review

BACKGROUND

Tablet splitting can provide dose flexibility and cost savings; however, pharmaceutical representatives typically discourage the practice.

AIM

To identify and summarise all published concerns related to tablet splitting and to present the experimental evidence that investigates those concerns.

DESIGN & SETTING

Systematic review and qualitative synthesis of tablet-splitting concerns and evidence.

METHOD

Medline and EMBASE databases were searched over all years of publication for articles in English discussing the splitting of tablets. Eligible articles included original research, narrative reviews, systematic reviews, and expert opinion.

RESULTS

After removing duplicates, 1837 potentially relevant articles underwent dual review, whereupon 1612 articles were excluded based on title and abstract. After examination of 225 full texts, 138 articles were included (one systematic review, four narrative reviews, 101 original research articles, and 32 opinion articles). The described concerns included difficulty breaking tablets, loss of mass, weight variability, chemical instability, overly rapid dosing if sustained-release medications are split, non-compliance, and patient confusion resulting in medication errors. No substantive evidence was found to support concerns regarding loss of mass, weight variability, chemical instability, or non-compliance. Evidence does support some older adults struggling to split tablets without tablet splitters, and the inappropriateness of splitting sustained-release preparations, given the potential for alteration of the rate of drug release for some products.

CONCLUSION

With the exception of sustained-release tablets, which should not be split, and excepting those older people who may struggle to split tablets based on physical limitations, there is little evidence to support tablet-splitting concerns.

Simultaneous Determination of Carvedilol, Enalaprilat, and Perindoprilat in Human Plasma Using LC–MS/MS and Its Application to a Pharmacokinetic Pilot Study

A method for the extraction and quantification of carvedilol, enalaprilat, and perindoprilat in 50 µL human plasma, using high-performance liquid chromatography with tandem mass spectrometry (LC–MS/MS) detection was developed and validated. Samples were prepared via protein precipitation with chromatographic separation on a Restek Ultra II Biphenyl column using gradient elution at a corresponding flowrate of 300 µL/min. Electrospray ionisation with mass detection at unit resolution in the multiple reaction monitoring (MRM) mode on an AB Sciex API 5500 mass spectrometer was used. Accuracy, precision, selectivity, sensitivity, matrix effects, recovery, process efficiency, and stability were assessed over the validation period. The assay was validated over the calibration range 0.2–200 ng/mL for all three analytes. The inter- and intra-day precision expressed as the coefficient of variation (CV) and accuracy (%Nom) all fell within acceptable limits. The overall recovery was calculated as 72.9%, 77.1%, and 77.0% for carvedilol, enalaprilat, and perindoprilat respectively, with the recovery being shown to be reproducible at the low, medium and high end of the calibration range for all three analytes. The method proved to be specific for all three analytes with no significant matrix effects observed. The validated method facilitated the analysis of carvedilol, enalaprilat, and perindoprilat in human plasma collected from adults as part of a pilot pharmacokinetic study. This validated analytical method lays the foundation for determining adherence in heart failure patients prescribed with carvedilol, enalapril and perindopril.

Medication Errors in Overweight and Obese Pediatric Patients: A Narrative Review

BACKGROUND

The childhood obesity epidemic in the United States has increased utilization of health care and prescribing of medications in overweight and obese children, yet it is unclear whether this has led to more medication errors. The objective of this study was to review all available literature on incidence and types of medication errors in overweight and obese children.

METHODS

A search of MEDLINE, Embase, and Scopus databases was conducted for all studies and oral abstracts through December 2020 reporting medication errors in overweight or obese children aged ≤ 18 years. All studies were identified and extracted via a Covidence database. Two reviewers independently reviewed studies and rated the methodologic quality of those included per GRADE (Grading of Recommendations, Assessment, Development and Evaluations) criteria.

RESULTS

The search identified 1,016 abstracts from databases. Following review, full text was obtained for 146 articles, of which 141 were excluded. A total of 5 studies met criteria for inclusion and described dosing errors of antimicrobials, anesthetics, and paracetamol in overweight and obese pediatric patients. Two of the 5 studies compared medication errors in obese to nonobese children, and both found that medication errors (both over- and underdosing) were generally more common among obese children. The identified reasons for medication errors included incorrect dosing weight, incorrect dosing strategy, over- and underdosing with weight-based and flat-fixed dosing, and inapposite use of age-based dosing schemas.

CONCLUSION

There is a paucity of patient safety evidence available evaluating medication use in overweight and obese children and associated medication errors. Overweight and obese children may be at increased risk of medication errors, although the clinical significance of this is unknown.

Effects of time on differential leucocyte counts and biochemical parameters of ovariohysterectomy, gastrotomy and intestinal resection and anastomosis in Nigerian indigenous dogs

Differential leucocytes counts and some biochemical parameters could be affected over time by surgical procedures leading to kidney failure. Hence this study evaluates the effects of ovariohysterectomy (OVH), gastrotomy (GAT) and intestinal resection and anastomosis (ITR) on differential leucocyte counts and some biochemical parameters in Nigerian dogs. Twelve dogs of both sexes weighing 10.8±0.7 kg were randomly divided into three experimental groups of four each. The dogs were pre-treated with atropine sulphate (0.04 mg/kg), Xylazine (2 mg/kg) and propofol (6 mg/kg) parenterally, for induction and maintenance of anaesthesia. Pentazocine (3 mg/kg) was injected after surgery. Pre and post-surgery blood samples were obtained at 0, 2, 24, 48, 72, 96, 120 and 144 h respectively to determine differentials in leucocyte counts, electrolytes, lactate, blood urea nitrogen (BUN) and serum creatinine. Mathematical formulas were used to calculate plasma creatinine, creatinine clearance, plasma creatinine clearance, creatinine half- life, urine creatinine and urine volume. There were significant increases (p ≤ 0.05) in mean sodium, chloride and bicarbonate concentrations at 2, 24, 48, 72, 96 and 120 h post-surgery in group 1 and 2, while group 3 had significant decreases (p ≤ 0.05) in sodium, chloride and bicarbonate ions. Lactate value decreased significantly (p<0.05) in group 1, and increased in group 2 and 3 respectively.BUN increased significantly (p<0.05) in group 1,2 and 3.However, there were significant increases (p<0.05) in lymphocyte concentrations in group 1 and 3, respectively. Monocytes decreased significantly (p<0.05) after surgery. Conclusion: Xylazine and propofol anaesthetics cause hyperlactatemia which can be detrimental in surgical patients with co-morbidities.

Elevated body fat increases amphetamine accumulation in brain: evidence from genetic and diet-induced forms of adiposity

Despite the high prevalence of obesity, little is known about its potential impact on the pharmacokinetics of psychotropic drugs. In the course of investigating the role of the microRNA system on neuronal signaling, we found that mice lacking the translin/trax microRNA-degrading enzyme display an exaggerated locomotor response to amphetamine. As these mice display robust adiposity in the context of normal body weight, we checked whether this phenotype might reflect elevated brain levels of amphetamine. To assess this hypothesis, we compared plasma and brain amphetamine levels of wild type and Tsn KO mice. Furthermore, we checked the effect of diet-induced increases in adiposity on plasma and brain amphetamine levels in wild type mice. Brain amphetamine levels were higher in Tsn KO mice than in wild type littermates and correlated with adiposity. Analysis of the effect of diet-induced increases in adiposity in wild type mice on brain amphetamine levels also demonstrated that brain amphetamine levels correlate with adiposity. Increased adiposity displayed by Tsn KO mice or by wild type mice fed a high-fat diet correlates with elevated brain amphetamine levels. As amphetamine and its analogues are widely used to treat attention deficit disorder, which is associated with obesity, further studies are warranted to assess the impact of adiposity on amphetamine levels in these patients.

Clinical considerations in providing intravenous sedation with midazolam for obese patients in dentistry

The widespread prevalence of obesity continues to rise. Obesity and dental disease share common risk factors and so the demand for dental care for obese patients is escalating. For some of these patients, there is a corresponding need to be able to provide intravenous sedation safely when it is necessary and appropriate to do so. However, obesity often presents with multiple comorbidities and airway complexities, leading to more challenging management and potentially increased risk. The risk assessment process as well as patient monitoring and management strategies will be explored in this article. By reviewing the literature from dentistry and other medical specialties, we also aim to establish the potential benefit in administering supplemental oxygen and the use of capnography in monitoring this cohort of patients.

The Influence of Obesity on Treatment and Outcome of Severely Burned Patients

Obesity and the related medical, social, and economic impacts are relevant multifactorial and chronic conditions that also have a meaningful impact on outcomes following a severe injury, including burns. In addition to burn-specific difficulties, such as adequate hypermetabolic response, fluid resuscitation, and early wound coverage, obese patients also present with common comorbidities, such as arterial hypertension, diabetes mellitus, or nonalcoholic fatty liver disease. In addition, the pathophysiologic response to severe burns can be enhanced. Besides the increased morbidity and mortality compared to burn patients with normal weight, obese patients present a challenge in fluid resuscitation, perioperative management, and difficulties in wound healing. The present work is an in-depth review of the current understanding of the influence of obesity on the management and outcome of severe burns.

The Crashing Obese Patient

The obesity pandemic now affects hundreds of millions of people worldwide. As obesity rates continue to increase, emergency physicians are called on with increasing frequency to resuscitate obese patients. This article discusses important anatomic, physiologic, and practical challenges imposed by obesity on resuscitative care. Impacts on hemodynamic monitoring, airway and ventilator management, and pharmacologic therapy are discussed. Finally, several important clinical scenarios (trauma, cardiac arrest, and sepsis), in which alterations to standard treatments may benefit obese patients, are highlighted.

Intraoperative immunomodulatory effects of sevoflurane versus total intravenous anesthesia with propofol in bariatric surgery (the OBESITA trial): study protocol for a randomized controlled pilot trial

Background

Obesity is associated with a chronic systemic inflammatory process. Volatile or intravenous anesthetic agents may modulate immune function, and may do so differentially in obesity. However, no study has evaluated whether these potential immunomodulatory effects differ according to type of anesthesia in obese patients undergoing laparoscopic bariatric surgery.

Methods/design

The OBESITA trial is a prospective, nonblinded, single-center, randomized, controlled clinical pilot trial. The trial will include 48 patients with a body mass index ≥ 35 kg/m², scheduled for laparoscopic bariatric surgery using sleeve or a Roux-en-Y gastric bypass technique, who will be allocated 1:1 to undergo general inhalational anesthesia with sevoflurane or total intravenous anesthesia (TIVA) with propofol. The primary endpoint is the difference in plasma interleukin (IL)-6 levels when comparing the two anesthetic agents. Blood samples will be collected prior to anesthesia induction (baseline), immediately after anesthetic induction, and before endotracheal extubation. Levels of other proinflammatory and anti-inflammatory cytokines, neutrophil chemotaxis, macrophage differentiation, phagocytosis, and occurrence of intraoperative and postoperative complications will also be evaluated.

Discussion

To our knowledge, this is the first randomized clinical trial designed to compare the effects of two different anesthetics on immunomodulation in obese patients undergoing laparoscopic bariatric surgery. Our hypothesis is that anesthesia with sevoflurane will result in a weaker proinflammatory response compared to anesthesia with propofol, with lower circulating levels of IL-6 and other proinflammatory mediators, and increased macrophage differentiation into the M2 phenotype in adipose tissue.

Trial registration

Registro Brasileiro de Ensaios Clínicos, RBR-77kfj5. Registered on 25 July 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3399-z) contains supplementary material, which is available to authorized users.

Clinical Pharmacokinetics and Pharmacodynamics of Propofol

Propofol is an intravenous hypnotic drug that is used for induction and maintenance of sedation and general anaesthesia. It exerts its effects through potentiation of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) at the GABAA receptor, and has gained widespread use due to its favourable drug effect profile. The main adverse effects are disturbances in cardiopulmonary physiology. Due to its narrow therapeutic margin, propofol should only be administered by practitioners trained and experienced in providing general anaesthesia. Many pharmacokinetic (PK) and pharmacodynamic (PD) models for propofol exist. Some are used to inform drug dosing guidelines, and some are also implemented in so-called target-controlled infusion devices, to calculate the infusion rates required for user-defined target plasma or effect-site concentrations. Most of the models were designed for use in a specific and well-defined patient category. However, models applicable in a more general population have recently been developed and published. The most recent example is the general purpose propofol model developed by Eleveld and colleagues. Retrospective predictive performance evaluations show that this model performs as well as, or even better than, PK models developed for specific populations, such as adults, children or the obese; however, prospective evaluation of the model is still required. Propofol undergoes extensive PK and PD interactions with both other hypnotic drugs and opioids. PD interactions are the most clinically significant, and, with other hypnotics, tend to be additive, whereas interactions with opioids tend to be highly synergistic. Response surface modelling provides a tool to gain understanding and explore these complex interactions. Visual displays illustrating the effect of these interactions in real time can aid clinicians in optimal drug dosing while minimizing adverse effects. In this review, we provide an overview of the PK and PD of propofol in order to refresh readers' knowledge of its clinical applications, while discussing the main avenues of research where significant recent advances have been made.

Overfed but undernourished: recognizing nutritional inadequacies/deficiencies in patients with overweight or obesity

Overweight and obesity are highly prevalent throughout the world and can adversely affect the nutritional status of individuals. Studies have shown that many people with obesity have inadequate intake of iron, calcium, magnesium, zinc, copper, folate and vitamins A and B₁₂, likely as a result of poor diet quality. Nutritional inadequacies or deficiencies may also occur due to altered pharmacokinetics in the individual with obesity and due to interactions in those with overweight or obesity with various pharmaceuticals. However, it has been demonstrated that the adult population in the United States as a whole is deficient in certain micronutrients as a result of the availability and overconsumption of high-calorie, low-nutrient processed foods. Poor nutrition may contribute to the development of certain chronic conditions, such as type 2 diabetes, which is already more prevalent in those with obesity. Clinicians need to be aware of these gaps, particularly in those individuals with obesity who are undergoing bariatric surgery or taking pharmaceutical products long term to facilitate weight loss. Patients with overweight or obesity likely struggle to achieve a balanced diet and may benefit from consultation with a dietitian. Along with providing recommendations for healthy eating and exercise, supplementation with specific micronutrients or multivitamins should be considered for individuals at the highest risk for or with established deficiencies. Further research is needed to understand the factors underlying nutritional inadequacies in individuals with overweight or obesity, as well as the outcomes of treatment strategies employed to address them.

Pharmacokinetics in Morbid Obesity: Influence of Two Bariatric Surgery Techniques on Paracetamol and Caffeine Metabolism

PURPOSE

The purpose of the study was to study the impact of the two most common bariatric surgery techniques on paracetamol pharmacokinetics (a marker of gastric emptying) and caffeine metabolism (a marker of liver function).

MATERIALS AND METHODS

In the present prospective study, we studied 24 morbid obese patients before, at 4 weeks, and 6 months after having undergone sleeve gastrectomy (n = 10) or Roux-en-Y gastric bypass (n = 14). For comparative purposes, 28 healthy controls (14 normal weights and 14 overweights) were also included in the study.

RESULTS

Paracetamol pharmacokinetics was altered in the obese participants leading to lower bioavailability. Bariatric surgery resulted in faster absorption and normalized pharmacokinetic parameters, prompting an increase in paracetamol bioavailability. No differences were found between surgical procedures. In the case of caffeine, the ratio paraxanthine/caffeine did not differ between morbid obese and healthy individuals. This ratio remained unmodified after surgery, indicating that the liver function (assessed by cytochrome P450 1A2 activity) was unaffected by obesity or bariatric surgery.

CONCLUSIONS

Paracetamol pharmacokinetics and caffeine plasma levels are altered in severely obese patients. The two studied bariatric surgical techniques normalize paracetamol oral bioavailability without impairing the liver function (measured by cytochrome P450 1A2 activity).

Risk factors for cardiopulmonary and respiratory arrest in medical and surgical hospital patients on opioid analgesics and sedatives

BACKGROUND

Opioid induced respiratory depression is a known cause of preventable death in hospitals. Medications with sedative properties additionally potentiate opioid-induced respiratory and sedative effects, thereby elevating the risk for adverse events. The goal of this study was to determine what specific factors increase the risk of in-hospital cardiopulmonary and respiratory arrest (CPRA) in medical and surgical patients on opioid and sedative therapy.

METHODS

The present study analyzed 14,504,809 medical inpatient and 6,771,882 surgical inpatient discharges reported into the Premier database from 2008 to 2012. Patients were divided in four categories: on opioids; on sedatives; on both opioids and sedatives; and on neither opioids nor sedatives.

RESULTS

During hospital admission, 57% of all medical patients and 90% of all surgical patients were prescribed opioids, sedatives, or both. Surgical patients had a higher incidence of CPRA than medical patients (6.17 vs. 3.77 events per 1000 admissions; Relative Risk: 1.64 [95%CI: 1.62-1.66; p<0.0001). Opioids and sedatives were found to be independent predictors of CPRA (adjusted OR of 2.24 [95%CI: 2.18-2.29] for opioids and adjusted OR 1.80 [95%CI: 1.75-1.85] for sedatives in medical patients, and adjusted OR of 1.12 [95%CI: 1.07-1.16] for opioids and adjusted OR of 1.58 [95%CI: 1.51-1.66] for sedatives in surgical patients), with the highest risk in groups who received both types of medications (adjusted OR of 3.83 [95% CI: 3.74-3.92] in medical patients, and adjusted OR of 2.34 [95% CI: 2.25-2.42] in surgical patients) compared with groups that received neither type of medication. The common risk factors of CPRA in medical and surgical patients receiving both opioids and sedatives were Hispanic origin, mild liver disease, obesity, and COPD. Additionally, medical and surgical groups had their own unique risk factors for CPRA when placed on opioid and sedative therapy.

CONCLUSIONS

Opioids and sedatives are independent and additive predictors of CPRA in both medical and surgical patients. Receiving both classes of medications further exacerbates the risk of CPRA for these patients. By identifying groups at risk among medical and surgical in-hospital patients, this study provides a step towards improving our understanding of how to use opioid and sedative medications safely, which may influence our treatment strategies and outcomes. More precise monitoring of selected high-risk patients may help prevent catastrophic cardiorespiratory complications from these medications. As a retrospective administrative database analysis, this study does not establish the causality or the temporality of the events but rather draws statistically significant associations between the clinical factors and outcomes.

Drug Dosing in Obese Children: Challenges and Evidence-Based Strategies

With the alarming increase of obesity in children, pediatricians are increasingly being confronted with difficult dosing decisions. Many drug labels do not provide specific dosing instructions for children who are obese. In this article, we describe the physiologic parameters altered by obesity and their influences on drug disposition and effect. We review the principles of allometry, and the key pharmacokinetic parameters that can be used to derive age appropriate dosing regimens. Last, we illustrate how appropriate weight descriptors can be selected, and how important PK parameters can be extrapolated for dosing in obese children when pediatric pharmacokinetic information is available.

Effects of Obesity and Leptin Deficiency on Morphine Pharmacokinetics in a Mouse Model

BACKGROUND

Obesity causes multiorgan dysfunction, specifically metabolic abnormalities in the liver. Obese patients are opioid-sensitive and have high rates of respiratory complications after surgery. Obesity also has been shown to cause resistance to leptin, an adipose-derived hormone that is key in regulating hunger, metabolism, and respiratory stimulation. We hypothesized that obesity and leptin deficiency impair opioid pharmacokinetics (PK) independently of one another.

METHODS

Morphine PK were characterized in C57BL/6J wild-type (WT), diet-induced obese (DIO), and leptin-deficient (ob/ob) mice, and in ob/ob mice given leptin-replacement (LR) therapy. WT mice received several dosing regimens of morphine. Obese mice (30 g) received one 80 mg/kg bolus of morphine. Blood was collected at fixed times after morphine injection for quantification of plasma morphine and morphine 3-glucuronide (M3G) levels. PK parameters used to evaluate morphine metabolism included area-under the curve (AUC150), maximal morphine concentration (CMAX), and M3G-to-morphine ratio, and drug elimination was determined by clearance (Cl/F), volume of distribution, and half-life (T1/2). PK parameters were compared between mouse groups by the use of 1-way analysis of variance, with P values less than .05 considered significant.

RESULTS

DIO compared with WT mice had significantly decreased morphine metabolism with lower M3G-to-morphine ratio (mean difference [MD]: -4.9; 95% confidence interval [CI]: -8.8 to -0.9) as well as a decreased Cl/F (MD: -4.0; 95% CI: -8.9 to -0.03) Ob/ob compared with WT mice had a large increase in morphine exposure with a greater AUC150 (MD: 980.4; 95% CI: 630.1-1330.6), CMAX (MD: 6.8; 95% CI: 2.7-10.9), and longer T1/2 (MD: 23.1; 95% CI: 10.5-35.6), as well as a decreased Cl/F (MD: -7.0; 95% CI: -11.6 to -2.7). Several PK parameters were significantly greater in ob/ob compared with DIO mice, including AUC150 (MD: 636.4; 95% CI: 207.4-1065.4), CMAX (MD: 5.3; 95% CI: 3.2-10.3), and T1/2 (MD: 18.3; 95% CI: 2.8-33.7). When leptin was replaced in ob/ob mice, PK parameters began to approach DIO and WT levels. LR compared with ob/ob mice had significant decreases in AUC150 (MD: -779.9; 95% CI: -1229.8 to -330), CMAX (MD: -6.1; 95% CI: -11.4 to -0.9), and T1/2 (MD: -19; 95% CI: -35.1 to -2.8). Metabolism increased with LR, with LR mice having a greater M3G-to-morphine ratio compared with DIO (MD: 5.3; 95% CI: 0.3-10.4).

CONCLUSIONS

Systemic effects associated with obesity decrease morphine metabolism and excretion. A previous study from our laboratory demonstrated that obesity and leptin deficiency decrease the sensitivity of central respiratory control centers to carbon dioxide. Obesity and leptin deficiency substantially decreased morphine metabolism and clearance, and replacing leptin attenuated the PK changes associated with leptin deficiency, suggesting leptin has a direct role in morphine metabolism.

Completeness in clerking: The surgical admissions proforma

BACKGROUND

The accessibility of surgical patient data is a key safety concern, and relies on efficient clerking and handovers. This project assessed whether the introduction of a surgical clerking proforma improved the recording of patient information in the surgical admissions unit (SAU) at Northwick Park Hospital.

MATERIALS AND METHODS

Existing patient notes were assessed on content and ease of access, using two independent surveys conducted over a 5-day period. The first survey audited patient notes before (n = 28) and after (n = 23) the introduction of the proforma. It assessed whether key patient details were documented, in line with the 17 criteria set out in the Guidelines for Clinicians on Medical Records and Notes by The Royal College of Surgeons in England. The second survey questioned healthcare professionals before (n = 25) and after (n = 17) proforma implementation on the accessibility of patient data and coherency of patient notes.

RESULTS

5 of the 17 criteria showed significant differences post proforma implementation. Of these differences, the recording of height and occupation was most notable (p < 0.01). Medication history, weight and investigations also showed significant increases in documentation (p < 0.05). In all 3 questions asked to healthcare professionals, fewer healthcare professionals were required to revisit archived notes following proforma implementation (p < 0.05).

CONCLUSION

Our study illustrates that a comprehensive surgical clerking proforma improves patient data documentation and saves healthcare professionals' time compared to the freehand clerking method. The implications of such work are far reaching, and if well implemented could allow a new reliable platform for further clinical audits.

Perioperative Pharmacologic Considerations in Obesity

Obesity has increased in incidence worldwide. Along with the increased number of obese patients, comorbid conditions are also more prevalent in this population. Obesity leads to changes in the physiology of patients along with an altered response to pharmacologic therapy. Vigilant perioperative physicians must be aware of the unique characteristics of administered agents in order to appropriately provide anesthetic care for obese patients. Because of the variability in tissue content in obese patients and changes in pharmacokinetic modeling, a one-size-fits-all approach is not justified and a more sophisticated and prudent approach is indicated.

Sugammadex ED90 dose to reverse the rocuronium neuromuscular blockade in obese patients

Objective

to determine the ED90 (minimum effective dose in 90% of patients) of sugammadex for the reversal of rocuronium-induced moderate neuromuscular blockade (NMB) in patients with grade III obesity undergoing bariatric surgery.

Methods

we conducted a prospective study with the biased coin up-and-down sequential design. We chosen the following doses: 2.0mg/Kg, 2.2mg/Kg, 2.4mg/Kg, 2.6mg/Kg, 2.8mg/Kg. The complete reversal of rocuronium-induced NMB considered a T4/T1 ratio ≥0.9 as measured by TOF. After induction of general anesthesia and calibration of the peripheral nerve stimulator and accelerometer, we injected rocuronium 0.6mg/kg. We administered propofol and remifentanil by continuous infusion, and intermittent boluses of rocuronium throughout the procedure.

Results

we evaluated 31 patients, of whom 26 had displayed successful reversal of the NMB with sugammadex, and failure in five. The mean time to complete moderate NMB reversal was 213 seconds (172-300, median 25-75%). The ED90 of sugammadex calculated by regression was 2.39mg/kg, with a 95% confidence interval of 2.27-2.46 mg/kg.

Conclusion

the ED90 of sugammadex in patients with grade III obesity or higher was 2.39mg/kg.

Impact of Norepinephrine Weight-Based Dosing Compared With Non–Weight-Based Dosing in Achieving Time to Goal Mean Arterial Pressure in Obese Patients With Septic Shock

Background: Currently, a lack of standardization exists in norepinephrine dosing units, the first-line vasopressor for septic shock. Timely achievement of goal mean arterial pressure (MAP) is dependent on optimal vasopressor dosing. Objective: To determine if weight-based dosing (WBD) of norepinephrine leads to earlier time to goal MAP compared with non-WBD in obese patients with septic shock. Methods: This was a retrospective, multicenter cohort study. Patients had a body mass index (BMI) ≥30 kg/m2 and received norepinephrine for septic shock with either a non-WBD strategy (between December 2009 and January 2013) or WBD strategy (between January 2013 and December 2015). The primary outcome was time to goal MAP. Secondary outcomes were norepinephrine duration, dose requirements, and development of treatment-related complications. Results: A total of 287 patients were included (WBD 144; non-WBD 143). There was no difference in median time to goal MAP (WBD 58 minutes, interquartile range [IQR] = 16.8-118.5, vs non-WBD 60 minutes, IQR = 17.5-193.5; P = 0.28). However, there was a difference in median cumulative norepinephrine dose (WBD 12.6 mg, IQR = 4.9-45.9, vs non-WBD 10.5 mg, IQR = 3.9-25.6; P = 0.04) and time to norepinephrine discontinuation (WBD 33 hours, IQR = 15-69, vs non-WBD 27 hours, IQR = 12-51; P = 0.03). There was no difference in rates of atrial fibrillation (WBD 15.3% vs non-WBD 23.7%; P = 0.07) or mortality (WBD 23.6% vs non-WBD 23.1%; P = 0.92). Conclusion: WBD of norepinephrine does not achieve time to goal MAP earlier in obese patients with septic shock. However, WBD may lead to higher norepinephrine cumulative dose requirements and prolonged time until norepinephrine discontinuation.

Observational study on patterns of neuromuscular blockade reversal

BACKGROUND

Using electronic health record data, we hypothesized that larger reversal doses are used for patients with deeper levels of neuromuscular blockade (NMB) as evidenced by the last recorded TOF measurement. We also examined if dosing regimens reflect current practice guidelines of using ideal body weight (IBW) for NMB agents and total body weight (TBW) for neostigmine.

METHODS

This is a retrospective observational study of adult, ASA 1-4 patients who underwent general anaesthesia and received non-depolarizing NMB agents between 01/01/2004 and 12/31/2013. For the primary outcome, percentages of cases receiving neostigmine and median doses administered for each subjective train-of-four (TOF) category were calculated. Secondary analyses evaluated associations between NMB dosing and neostigmine administration based on Body Mass Index (BMI) categories.

RESULTS

A total of 135,633 cases met inclusion criteria for the study. There was no clinically significant difference in median neostigmine dosing based on last TOF count prior to reversal administration: 37.5 mcg/kg for TOF of 4/4 vs. 37.9 mcg/kg for TOF of 0/4 for the total neostigmine dose. Significantly higher number of patients with lower TOF counts received additional neostigmine administration: 5.7 % for 0/4 vs. 1.5 % for 4/4 TOF counts. The median times to extubation following neostigmine administration were clinically similar across TOF count categories. The median doses for neostigmine based on TBW decreased with higher BMI categories and were significantly different between the lowest and highest categories: 42.8 mcg/kg vs 30.8 mcg/kg for total doses (p < .0001) respectively. The percentages of cases requiring reversal in addition to the initial dose increased with increasing BMI categories and were 2.1 % for BMI < 18 vs. 3.3 % for BMI ≥ 40. The total median dose of NMB agents in ED95 equivalents per IBW increased from 2.9 in the Underweight category to 4.2 in the Class III Obese category. The majority of patients in the pancuronium subgroup received very low ED95 equivalent dose of 0.1 and did not require reversal. Patients receiving cisatracurium were given significantly higher median ED95 equivalent dose of 5.6 vs 2.8-3.9 compared to other intermediate acting NMB agents, while receiving clinically similar doses of neostigmine.

CONCLUSIONS

Neither neostigmine dosing nor times to extubation were affected by the depth of the neuromuscular blockade prior to reversal. The need for additional reversal, or rescue, correlated strongly with the depth of NMB. There was significant variability in neostigmine dosing across the BMI categories. Underweight patients received relatively lower NMB doses while simultaneously receiving relatively higher reversal doses, and the opposite was true for patients with BMI >40.

A Review of the Toxicologic Implications of Obesity

The increasing prevalence of obesity in developed nations has far-reaching implications for medical toxicology. The management of obese patients is complicated by comorbid illnesses, changes in cardiovascular and respiratory physiology, alterations in pharmacokinetics, and a lack of studies to identify appropriate dosing for current therapeutics and antidotes. In this review article, we examine obesity-associated physiologic and pharmacokinetic changes that may increase the vulnerability of obese patients to overdose. Further research is needed to characterize the relationship between drug toxicity and obesity.

The potential for nutritional components of food items used for enrichment of research animals to act as confounding variables in toxicology studies

Produce and other non-certified foods may be provided to laboratory animals for enrichment, but this practice can generate scientific concerns, particularly if these food items contain nutrients that are pharmacologically active or affect animals' consumption of the basal diet. The author reviews information on potential for a number of nutritional components of food items to affect study data. On the basis of published effect levels, he proposes an upper limit for the consumption of each component in enrichment items relative to the amount present in a standard basal diet. He then assesses the amounts of these nutritional components in a broad range of food enrichment items and proposes a maximum serving size for each item for several common laboratory animals. Total caloric content and sugar content are the limiting components for many enrichment food items, but most items may be used as enrichment for laboratory animals without affecting study results, as long as the amounts of the items provided are managed.

A retrospective description of anesthetic medication dosing in overweight and obese children

INTRODUCTION

Pediatric obesity is a major health concern in the United States and as many as 34% of those who require general anesthesia are overweight or obese (OW). The lack of data and recommendations for dosing medications in obese children leaves significant gaps in the understanding of correct dosing in the clinical setting.

OBJECTIVE

To determine whether OW children were more likely to receive doses of medications outside the recommended range.

METHODS

Following IRB approval, patient medical records were queried to identify children 2 through 17 years who underwent noncardiac surgeries and received at least one medication of interest. Children with hepatic disease, renal disease, neurological impairment, sleep-disordered breathing, or missing height or weight measurements were excluded. Children were stratified into weight categories based on age and gender percentiles as per CDC guidelines. Those ≥85th percentile were classified as overweight/obese. Ideal and lean weight (for age, gender) were calculated. Drug doses were stratified as under-dosed (>10% below minimum recommended dose), overdosed (>10% above maximum recommended dose), or within recommended dose (dose ± 10%). Actual doses were compared to recommended doses as per actual, ideal, or lean weight (as recommended for specific drugs) in the overweight/obese groups vs the control weight (CW) group.

RESULTS

Ten thousand five hundred and nine doses were reviewed. Overweight/obese children were more likely to receive doses outside the recommended dose range than the CW group.

CONCLUSIONS

Overweight/obese children were more likely to receive doses of common anesthetic medications outside the recommended doses potentially adding risk of adverse outcomes in these children.

Designing intelligent anesthesia for a changing patient demographic: a consensus statement to provide guidance for specialist and non-specialist anesthetists written by members of and endorsed by the Society for Obesity and Bariatric Anaesthesia (SOBA)

BACKGROUND

As a result of the increasing prevalence of obesity in the UK, anesthetists are increasingly encountering overweight and obese patients in routine practice. There is currently a paucity of evidence to guide best clinical practice for anesthetists managing overweight and obese patients. The current guidelines from the Association of Anaesthetists of Great Britain and Ireland (AAGBI), entitled Peri-Operative Management of the Morbidly Obese Patient, give an excellent overview of organizational issues, but leave much clinical detail to the discretion of the individual clinician.

METHODS

In May 2010, a panel of experts convened to develop consensus on anesthesia of overweight, obese and morbidly obese patients, in consultation with the Society for Obesity and Bariatric Anaesthesia (SOBA). All Panel members are practicing clinicians from recognized bariatric surgical training centers and have extensive experience of anesthesia for obese patients. This statement aims to provide guiding principles on best practice for this challenging patient demographic, and to increase awareness of current issues so that these can be addressed more appropriately.

RESULTS

In this document, we emphasize key principles for best practice, rather than giving prescriptive guidance and specific regimens for all clinical eventualities. We provide evidence-based justification for best-practice techniques, where this exists. In areas for which there is no evidence, but there is clear consensus, we offer this as guidance. We also aim to dispel misconceptions that have arisen in the anesthetic practice of overweight, obese, and morbidly obese patients.

CONCLUSION

Ultimately, the choice of specific technique depends on clinician experience, patient characteristics, and center facilities. As well as providing guiding principles for anesthesia, this consensus statement also highlights other areas where anesthetists can contribute towards the enhanced recovery and overall quality of patient care.