Ideal Body Weight Group Research Articles

Comparison of Fat-Free Mass and Ideal Body Weight Scalar for Anesthetic Induction Dose of Propofol in Patients with Morbid Obesity: A Double-Blind, Randomized Clinical Trial.

Obesity is a growing problem worldwide and can affect both the pharmacodynamics and pharmacokinetics of various drugs, including anesthetics, resulting in the under-or overdosing of certain drugs. There is no consensus on the ideal dosing regimen for obese populations. In this study, 2 weight-based dosing of propofol used for induction of anesthesia were compared in terms of the onset of action time, adequacy of anesthesia, and effects on hemodynamic indices (eg, heart rate [HR] and blood pressure). In this randomized, double-blind clinical trial, 40 patients with morbid obesity (MO) scheduled for bariatric surgery with body mass index (BMI) > 35, age 18 - 59 years, American Society of Anesthesiologists physical status (ASA-PS) II and III were randomly divided into 2 groups, using block randomization method, to receive 2 mg/kg of propofol for induction of anesthesia based on either fat-free mass (FFM) group or ideal body weight (IBW) group. The primary outcome was the time duration to reach the bispectral index (BIS) ≤ 60. Time to the disappearance of eyelash reflex, signs of inadequate anesthesia (ie, BIS > 60, straining during intubation, or eye-opening), requirements for additional doses, and hemodynamic indices (including HR and mean arterial pressure [MAP]) were also compared. The mean time to reach BIS ≤ 60 was 134.1 s in the FFM group and 148.7 s in the IBW group. This difference was not statistically significant (P = 0.334). The time of disappearance of eyelash reflex was also not significantly different between the study groups (P = 0.814). However, 2 patients in the FFM group and 8 patients in the IBW group showed signs of inadequate anesthesia and required additional doses. This difference was statistically significant (P = 0.032). Hemodynamic variables, before and 2 min after propofol induction dose administration were comparable between the study groups (P = 0.520, P = 0.327, P = 0.847, P = 0.516 for pre-intervention MAP, post-intervention MAP, pre-intervention HR, and post-intervention HR, respectively). Propofol dosing, based on FFM and IBW, for induction of anesthesia, provides comparable onset time of action and hemodynamic effects; however, in terms of the adequacy of anesthesia, the dosing based on FFM is more favorable compared to the dosing based on IBW.

Comparison of dosing strategies in obese patients prescribed intravenous acyclovir and evaluation of rate of acute kidney injury

IntroductionThere is limited guidance on the most appropriate dosing strategy for intravenous (IV) acyclovir in obese patients. The manufacturer's labelling suggests using ideal body weight (IBW); however, previous pharmacokinetic studies of obese patients have shown more rapid systemic clearance and lower area under the curve and peak concentrations compared with patients with a body mass index (BMI) < 30 kg/m2. Although pharmacokinetic data suggest that plasma concentrations of acyclovir are best predicted when using adjusted body weight (AdjBW) doses, there is concern about higher rates of acute kidney injury (AKI). MethodsThis was a retrospective cohort review of adult patients with a BMI ≥ 30 kg/m2 prescribed IV acyclovir ≥ 48 hours between 1 January 2014 and 31 August 2021 at a 511-bed academic medical centre. The primary objective was to compare AdjBW with IBW dosing in obese patients who had been prescribed IV acyclovir and to determine whether AdjBW dosing results in higher rates of AKI. ResultsNinety-four patients were included: 61 were in the IBW cohort and 33 were in the AdjBW cohort. The median BMI [IQR] for all patients was 34.7 kg/m2 [31.8–40.6]. Patients in the AdjBW cohort received a significantly higher median acyclovir dose of 800 mg/dose [IQR 700–850] compared with 600 mg/dose [IQR 500–700] for the IBW cohort (P ≤ 0.0001). No patients dosed using AdjBW developed AKI compared with eight (13.1%) in the IBW group. ConclusionIn this study, 8.5% of all obese patients receiving acyclovir developed AKI. Further studies are needed to confirm dosing recommendations.

196. Assessing the Clinical Impact of Intravenous Acyclovir Dosing in Obese Patients: Should We Be Using Ideal, Adjusted, or Total Body Weight?

BackgroundObesity impacts the pharmacokinetics and pharmacodynamics of medications. Pharmacokinetic studies of intravenous (IV) acyclovir have demonstrated that dosing obese patients according to their ideal body weight (IBW) may provide a sub-therapeutic dose, while dosing based on total body weight (TBW) may increase adverse effects. This has led to the use of adjusted body weight (AdjBW) for dosing in this population; however, this has not been evaluated clinically. The purpose of this study is to assess the impact of different dosing strategies of IV acyclovir in obese patients.MethodsThis retrospective observational chart review evaluated adult patients admitted to Long Island Jewish Medical Center with a body mass index greater than or equal to 30 kg/m2 who received at least 48 hours of high-dose IV acyclovir therapy during the study period of January 2014 to August 2019. Patients were stratified to IBW, AdjBW, and TBW for analysis. The primary statistical tests utilized include descriptive statistics and logistic regression. The primary endpoint was the outcome of infection. The secondary endpoints included duration of therapy, length of stay, and adverse effects.Results51 patients were included in the efficacy analysis and 84 patients were included in the safety analysis. Treatment failure occurred in 3 out of 51 patients (1 patient in IBW group, 2 patients in AdjBW group, p=0.445). There was no significant difference in median length of stay (p=0.977) or median duration of IV therapy (p=0.78). Nephrotoxicity occurred in 22.2%, 19.2%, and 22.7% of patients in the IBW, AdjBW, and TBW groups respectively (p=1).ConclusionWhen comparing different dosing modalities, there was no significant difference in the outcome of infection, duration of therapy, or length of stay. The results of this study were limited by small sample size. However, dosing patients according to AdjBW led to smaller doses of acyclovir, and therefore less drug exposure.Disclosures All Authors: No reported disclosures

Effect of a Leucine/Pyridoxine Nutraceutical on Caloric Intake and Body Composition of Obese Dogs Losing Weight.

The aim of this 29-week randomized, positively and negatively controlled study was to investigate whether a nutraceutical containing 1 g leucine and 13 mg pyridoxine can enhance weight loss while maintaining lean muscle mass in obese dogs. Twenty-four healthy, 2-year-old beagles were initially divided into obesification (n = 18) or ideal body weight groups (n = 6). After obesification, the 18 dogs were divided into three weight loss groups and fed one of the following over 12 weeks: nutraceutical with canned adult diet (CAD; ObN), placebo with CAD (ObP), or a canned therapeutic weight loss diet (WLD). Dogs in the ideal body weight (IBW) group were fed maintenance calorie requirements with CAD over 12 weeks. Based on MANOVA, ObN and WLD lost similar amounts of total weight (3.6 ± 0.9 vs. 4.4 ± 1.1 kg, respectively) and fat mass (3.1 ± 0.6 vs. 3.9 ± 0.8 kg, respectively) after 12 weeks of treatment, and more than ObP (1.1 ± 1.2 kg weight; 0.9 ± 1.0 kg fat; p < 0.0001). These data show the nutraceutical is a promising option for successful weight loss in dogs. Maintenance levels of CAD were able to induce weight loss without risk of hypo- or anorexia, or the need to switch diets or restrict energy intake.

Adjusted calculation model of heparin management during cardiopulmonary bypass in obese patients: A randomised controlled trial.

Anticoagulation during cardiopulmonary bypass (CPB) is usually adapted to total body weight (TBW). This may be inaccurate in obese patients and lead to heparin overdose with a risk of bleeding. To validate the efficacy and safety of an adjusted calculation model of heparin dosing based on ideal body weight (IBW) rather than TBW in obese CPB patients, with an expected target mean plasma heparin concentration of 4.5 IU ml after onset of CPB in the experimental group. Randomised controlled study. University hospital. Sixty obese patients (BMI ≥ 30 kg m) scheduled for CPB were included from January to June 2016. Patients received a bolus dose of unfractionated heparin of either 300 IU kg of TBW or 340 IU kg of IBW before onset of CPB. Additional adjusted boluses were injected to maintain an activated clotting time (ACT) of at least 400 s. Plasma heparin concentration and ACT were measured at different time points. Total heparin doses and transfusion requirements were recorded. The target heparin concentration of 4.5 IU ml was reached in the IBW group at the onset of CPB and maintained at all time points during CPB. Heparin concentrations were significantly higher in the TBW group after the bolus (6.52 ± 0.97 vs. 4.54 ± 1.13 IU ml, P < 0.001) and after cardioplegia (5.10 ± 1.03 vs. 4.31 ± 1.00 IU ml, P = 0.02). Total heparin doses were significantly higher in the TBW group. Mean ACT was significantly lower in the IBW group but remained over 400 s during CPB. The correlation between heparin and ACT was poor. Peri-operative bleeding and transfusion requirements were comparable. No thrombotic event occurred in the CPB circuit. The current IBW-adjusted regimen of heparin administration may be used efficiently in obese CPB patients, thereby avoiding overdose which cannot be accurately assessed by ACT monitoring alone. ClinicalTrials.gov identifier: NCT02675647.

Abstract PR631

Background & Objectives: Atelectasis is aggravated on induction of anesthesia and pneumoperitoneum in the morbidly obese. Currently employed per-operative ventilation strategy, based on lung protection strategy, require recruitment maneuver (RM) for optimal gas exchange. Lower tidal volume (VT) is recommended in patients with acute lung injury for positive pressure ventilation (PPV). There is no evidence to the premise of using a lower VT in morbidly obese patients. Parameter on which to base tidal volume (VT) in these patients is still not validated. During anaesthesia, appropriate VT is required to minimize obligate aggravation of atelectasis. Abdominal obesity (AO) is a better predictor of severity of obesity than body mass index (BMI). Waist circumference (WC) is a fair measure of AO and may be used for setting VT for PPV strategy for the obese. Ideal body weight (IBW) was also analyzed for VT calculation and its impact on gas exchange and pulmonary morbidity (if any). Materials & Methods: A prospective cohort of sixty morbidly obese patients (BMI>35 kg m-2), randomized into two groups, received PPV determined by IBW and AO-based VT calculation. Anaesthesia technique was standardized for the two groups. In AO group, VT was calculated by formula WC in cm × 6.0 ml and in IBW group by equation IBW (kg) × 13ml. We applied a PEEP of 5 cm H2O PEEP in AO group and 10 cm H2O in IBW group. Respiratory rate (13/min) and I:E (1:2) ratio were similar for both groups. Primary outcome variable was PaCO2 < 45 mmHg and PaO2 > 80 mmHg which were determined by taking serial ABG samples. Postoperative pulmonary morbidity was sought in all the participants. Results: All patients returned satisfactory oxygen saturation and arterial partial pressure of oxygen (PaO2) (Figure. 1). In the AO group, after creation of pneumoperitoneum with the exception of three patients who had hypocapnia, rest all maintained partial pressure of carbon dioxide (PaCO2) within the normal range (Figure.2). Three patients had hypercarbia (range: 52-54 mmHg) one hour after the first ABG measurement. Largely, the acid base balance was within the normal range in most patients. One patient was excluded from study, as he required RM for ABG optimization. IBW group patients were hypocapnic, but maintained oxygenation. No patient in the IBW group was excluded from study. Intraoperative haemodynamics were maintained within normal range in all the patients. Both ventilation strategies resulted in satisfactory oxygenation. AO based regimen gave satisfactory gas exchange in majority of patients. Ventilation regimen using IBW resulted in hyperventilation. No patient had pulmonary shortcoming. Conclusion: The ventilation strategy based on waist circumference returned superior gas exchange (no hyperventilation), it holds promise for being proposed as safe and effective alternative to conventional ventilation option. Disclosure of Interest: None declared

Effects of Obesity and Obesity-Related Molecules on Canine Mammary Gland Tumors.

Obesity can affect the clinical course of a number of diseases, including breast cancer in women and mammary gland tumors in female dogs, via the secretion of various cytokines and hormones. The objective of this study was to examine the expression patterns of obesity-related molecules such as aromatase, leptin, and insulin-like growth factor 1 receptor (IGF-1 R) in canine mammary carcinomas (CMCs) on the basis of the body condition score (BCS). Comparative analyses of the expression of these molecules, together with prognostic factors for CMCs, including hormone receptors (HRs; estrogen and progesterone receptors), lymphatic invasion, central necrosis of the tumor, and histologic grade, were performed on 56 CMCs. The mean age of CMC onset was lower in the overweight or obese group (8.7 ± 1.9 years) than in the lean or ideal body weight group (10.4 ± 2.7 years). The proportion of poorly differentiated (grade III) tumors was significantly higher in the overweight or obese female dogs. Aromatase expression was significantly higher in the overweight or obese group and was correlated with the expression of HRs (P = .025). These findings suggest that overweight or obese status might affect the development and behavior of CMCs by tumor-adipocyte interactions and increased HR-related tumor growth.

Sugammadex and ideal body weight in bariatric surgery: the debate continues.

I read with great interest the paper by Sanfilippo et al., evaluating the safety and efficacy of sugammadex administered on the basis of ideal body weight (IBW) to reverse neuromuscular blockade (NMB) at the reappearance of second twitch during train-of-four (TOF) stimulation [1]. However, this study raises several issues that deserve comment. First, the authors chose a TOF ratio of 0.9 after sugammadex administration based on IBW as their primary endpoint [1]. A TOF ratio of 0.9 may not indicate full recovery, as this ratio can be associated with impaired neuromuscular transmission [2], inhibition of the hypoxic ventilatory response, and upper airway or pharyngeal dysfunction [3]. Based on acceleromyography studies, the current recommendation is that a TOF ratio greater than or equal to 1.0 should be used to confirm complete recovery from NMB [3]. Second, the TOF ratio observed before tracheal extubation was 0.90 ± 0.57 in the IBW group compared to 0.91 ± 0.08 observed in the real body weight (RBW) group [1]. Considering the standard deviation from the mean value, not all patients reached a TOF ratio greater than or equal to 0.9 before tracheal extubation in the IBW group [1]. In another study, a single dose of sugammadex based on IBW was associated with failure to achieve a TOF ratio greater than or equal to 0.9 in 23% and 40% of patients who had moderate and deep NMB, respectively [4]. These patients required a rescue dose of sugammadex, indicating that a high percentage of slow responders should be expected in obese patients and that there is potential risk of blockade reoccurrence [4]. Finally, the median time for recovery to a TOF ratio of 0.9 was slower in the IBW group than in the RBW group (151 ± 44 versus 121 ± 55 sec) [1]. Even if signs of residual curarization were not observed in the patients enrolled in the study [1], however, a slow recovery may be an expression of the ineffectiveness of the dose of sugammadex [5, 6] and the combination of underdosing and delayed response may be associated with recurarization [6]. So, the reversal of NMB with sugammadex dosed on the basis of IBW in obese patients requires a special observation in the postoperative period, being obese patients at risk of potential upper airway obstruction and respiratory failure [3–6]. Therefore, IBW does not appear to offer a proper dosing scalar for sugammadex administration in obese patients and requires close surveillance and neuromuscular monitoring during the postoperative period [3–6]. In contrast, with sugammadex administered on the basis of RBW, obtaining a TOF ratio greater than or equal to 1.0 with acceleromyography is a relatively easy goal to achieve [5–7]. Thus, the current evidence suggests that sugammadex administered to reverse NMB at the reappearance of second twitch during TOF stimulation on the basis of RBW has the full potential for improving care and safety of obese patients.

Feasibility of using corrected body weight to set tide volume for mechanical ventilation during general anesthesia in obese patients

Objective To evaluate the feasibility of using corrected body weight to set the tide volume (VT) for mechanical ventilation during general anesthesia in obese patients.Methods Sixty ASA physical status Ⅰ or Ⅱ obese patients,with a body mass index of 28-44 kg/m2,scheduled for elective extremity surgery under general anesthesia,were randomly divided into 3 groups (n =20 each):VT based on actual body weight group (group A),VT based on ideal body weight group (group Ⅰ),and VT based on corrected body weight group (group C).The pulmonary function of all patients was normal.The patients were endotracheally intubated and mechanically ventilated after induction of anesthesia.According to the corresponding body weight,the initial VT was set based on 8 ml/kg in each group (RR 15 bpm,I ∶ E =1 ∶ 2,FiO2 =100％).At 10 min after start of mechanical ventilation,peak airway pressure (Ppeak),airway plateau pressure (Pplat),airwayresistance (Raw) were recorded.Arterial blood samples were collected at 30 min of mechanical ventilation for blood gas analysis and PaO2,PaCO2 and the patients requiring readjustment of VT (PaCO2 ＞ 45 mm Hg or ＜ 35 mm Hg) were also recorded.Results Compared with group A,PaCO2 was significantly increased and Ppeak,Pplat and Raw were decreased in I and C groups (P ＜ 0.01).PaCO2 was significantly lower and Ppeak,Pplat and Raw were higher in group C than in group Ⅰ(P ＜ 0.01 or 0.05).There were no patients requiring readjustment of VT in group C,however,95％ patients required readjustment of V+ in group A and 80％ in group B.The percentage of patients requiring readjustment of VT was significantly higher in A and B groups than in group C (P ＜ 0.01).Conclusion Corrected body weight based on 8 ml/kg can be used to set the Vr for mechanical ventilation during general anesthesia in obese patients with normal pulmonary function. Key words: Body weight ; Obesity ; Tidal volume ; Respiration,artificial; Anesthesia, general

Sugammadex and Ideal Body Weight in Bariatric Surgery

Background. The obese patients have differences in body composition, drug distribution, and metabolism. Sugammadex at T 2 recovery in a dose of 2 mg kg−1 of real body weight (RBW) can completely reverse the NMB block; in our study we investigated the safety and efficacy of Sugammadex dose based on their ideal body weight (IBW). Methods. 40 patients of both sexes undergoing laparoscopic bariatric surgery were enrolled divided into 2 groups according to the dose of Sugammadex: the first received a dose of 2 mg kg−1 of IBW and the second received a dose of 2 mg kg−1 of RBW. Both were anesthetized with doses calculated according to the IBW: fentanyl 2 μg kg−1, propofol 3 mg kg−1, rocuronium 0,6 mg kg−1, oxygen, air, and desflurane (6–8%). Maintenance doses of rocuronium were 1/4 of the intubation dose. Sugammadex was administrated at T 2 recovery. Results. The durations of intubation and maintenance doses of rocuronium were similar in both groups. In IBW group, the T 4/T 1 value of 0.9 was reached in 151 ± 44 seconds and in 121 ± 55 seconds in RBW group (P = 0.07). Discussion. Recovery times to T 4/T 1 of 0.9 are surprisingly similar in both groups without observing any postoperative residual curarization. Conclusion. Sugammadex doses calculated according to the IBW are certainly safe for a rapid recovery and absence of PORC.

Comparative evaluation of atracurium dosed on ideal body weight vs. total body weight in morbidly obese patients

Different conflicting reports have been published for the use of atracurium in morbidly obese patients. Dosing of atracurium based on lean body mass, total body weight, and total body weight with a dose reduction for every 10 kg more than 70 kg have been proposed. The current prospective randomized double-blind study compares atracurium 0.5 mg kg(-1) ideal body weight vs. 0.5 mg kg(-1) total body weight when used as a muscle relaxant in morbidly obese patients undergoing bariatric surgery. Based on our results in patients with body weights varying from 112 to 260 kg, we have concluded that atracurium 0.5 mg kg(-1) ideal body weight results in a predictable profile of muscle relaxation allowing for adequate intubation conditions and recovery of muscle strength within 60 min with lack of need for antagonism. A dose-dependent prolongation of action is shown when dosing is based on total body weight. This double-blind randomized study evaluated atracurium dosing based on ideal body weight vs. total body weight for muscle relaxation in morbidly obese patients undergoing bariatric surgery. Twenty patients (body weight 112-260 kg, BMI 38-79 kg m(-2) ) were randomized to receive atracurium 0.5 mg kg(-1) ideal body weight vs. 0.5 mg kg(-1) total body weight. Primary endpoint was neuromuscular blockade using train-of-four ratios (TOF ratios) and secondary endpoints were intubation conditions and need for antagonism with neostigmine. In the ideal body weight group, times to recovery of TOF ratio from 0 to 5%, 50% and 75% were significantly shorter [TOF ratio from 0 to 5%: mean difference 30 min (95% CI 23, 39 min)] and with lower variability compared with the total body weight group. In the total body weight group there was a significant correlation between atracurium dose and time to a TOF ratio of 5% (r= 0.82, P < 0.001), which was absent in the ideal body weight group (r= 0.24). In both groups, intubation conditions were good while 70% of the patients in the total body weight group needed neostigmine at the end of surgery compared with 0% in the ideal body weight group. In morbid obesity (112-260 kg), atracurium 0.5 mg kg(-1) ideal body weight results in a predictable profile of muscle relaxation allowing for adequate intubation conditions and recovery of muscle strength to a TOF ratio >90% within 60 min with lack of need for antagonism. A dose-dependent prolongation of action is shown when dosing is based on total body weight.

Should Dosing of Rocuronium in Obese Patients Be Based on Ideal or Corrected Body Weight?

Pharmacokinetic studies in obese patients suggest that dosing of rocuronium should be based on ideal body weight (IBW). This may, however, result in a prolonged onset time or compromised conditions for tracheal intubation. In this study, we compared onset time, conditions for tracheal intubation, and duration of action in obese patients when the intubation dose of rocuronium was based on three different weight corrections. Fifty-one obese patients, with a median (range) body mass index of 44 (34-72) kg/m2, scheduled for laparoscopic gastric banding or gastric bypass under propofol-remifentanil anesthesia were randomized into three groups. The patients received rocuronium (0.6 mg/kg) based on IBW (IBW group, n = 17), IBW plus 20% of excess weight (corrected body weight [CBW]20% group, n = 17), or IBW plus 40% of excess weight (CBW40% group, n = 17). Propofol was administered as a bolus of 200 mg and an infusion at 5 mg x kg(-1) x h(-1) and remifentanil was administered at 1.0 microg x kg(-1) x min(-1), both according to CBW40%. Neuromuscular function was monitored with train-of-four nerve stimulation and acceleromyography. The primary end point was duration of action, defined as time to reappearance of the fourth twitch in train-of-four. The median (range) duration of action was 32 (18-49), 38 (25-66), and 42 (24-66) min in the IBW, CBW20%, and CBW40% groups, respectively (P = 0.001 for comparison of the IBW and CBW40% group). There were no significant differences in onset time (85 vs 84 vs 80 s) or in intubation conditions 90 s after administration of rocuronium. In obese patients undergoing gastric banding or gastric bypass, rocuronium dosed according to IBW provided a shorter duration of action without a significantly prolonged onset time or compromised conditions for tracheal intubation.

Acute phase response in malnourished patients with Crohn's disease

The acute phase reactants, C-reactive protein (CRP) and α1 acid glycoprotein, are elevated in active Crohn's disease and can be used as markers of disease activity. It is not known whether the acute phase response is impaired in patients with malnutrition. The acute phase response of CRP and α1 acid glycoprotein was measured in 21 patients requiring in-patient treatment for active Crohn's disease. Ten malnourished patients (being less than 80% ideal body weight—Group 1) had a similar acute phase response compared to 11 well nourished patients (Group 2). Both groups had similar disease activity as assessed by clinical score, erythrocyte sedimentation rate and gastrointestinal protein loss. Malnourished patients with active Crohn's disease are able to mount an appropriate acute phase response. Acute phase reactants can be used as markers of disease activity in patients with Crohn's disease whose nutritional status is unknown.

Volume of Distribution of Theophylline in Acute Exacerbations of Reversible Airway Disease: Effect of Body Weight

The literature is unclear as to whether theophylline loading doses should be based on total body weight (TBW) or ideal body weight (IBW). The objective of this study was to determine the most appropriate body weight for estimation of volume of distribution (Vd) in calculating theophylline loading dose in patients with acute bronchospasm. Fifty-four adult patients with acute bronchospasm requiring intravenous (IV) theophylline therapy were entered into the study. Patients were randomized into three theophylline loading dose groups based on (1) TBW, (2) IBW, and (3) adjusted body weight (ABW). Initial serum theophylline concentrations were used to determine an IV loading dose to reach a plasma concentration of 12 to 15 micrograms/ml. Percent prediction error was used to determine the appropriateness of each dosing group. Volumes of distribution were also determined for each group. There was a statistically significant difference at p less than 0.01 in the percent prediction error when patients in the TBW group were compared to the IBW and ABW groups. A statistically significant difference in the Vd was observed between the TBW and IBW group (p less than 0.01). We conclude that IBW is more appropriate than TBW or ABW for determining theophylline loading dose in patients with acute bronchospasm.