Advertisement

Sign up for our daily newsletter

Advertisement

Propofol induction dose morbid obesity: Morbid obesity – Drug dosing

Variation in postoperative analgesic requirements in the morbidly obese following gastric bypass surgery.

William Murphy
Friday, July 6, 2018
Advertisement
  • About BJA. Article Navigation.

  • All procedures performed in this study involving human participants were in accordance with the Declaration of Helsinki as revised in

  • According to the conventional instructions, the calculation of propofol induction dosage based on TBW can lead to overdose in morbidly obese patients. Relationship between propofol induction dose and body weight in lean control subjects and MO subjects.

Introduction

Anesthesiology ; 89 : — In anesthesia induction, the conditions of sufficient anesthetic depth and the stability of the cardiovascular system must propofol induction dose morbid obesity taken into account. The dose range in this study is greater than the dose range of patients of normal body size listed in the instructions for propofol. For example, derangements in cardiac and respiratory function associated with MO exaggerate side-effects of anaesthetics and narrow the therapeutic window. Sign In.

Furthermore, the occurrence of an adverse drug event can lead to premature discontinuation of therapy and substitution with a less attractive alternative i. Is total body weight an appropriate predictor for propofol maintenance dose? JFB: Development of manuscript outline, literature search, literature evaluation, crafting of recommendations, manuscript preparation, and critical review. Availability of data and materials Not applicable. Mahmood I.

Dosing using lean body weight was therefore recommended. Further, clearance of ketamine, which becomes more of an issue with sustained dosing, is a infuction of propofol induction dose morbid obesity body mass and not likely to increase in proportion to fat mass in patients with obesity. Download PDF. Predictors of hypotension associated with propofol in trauma patients. Article Google Scholar Torsades de Pointes associated with intravenous haloperidol in critically ill patients. Despite these concerns, etomidate continues to be used and investigated as an agent for RSI with a usual dose of 0.

Furthermore, the inherent differences in the endpoints targeted with each strategy i. Pharmacokinetics and analgesic effect of ketamine in man. Summary of dosing recommendations for medications used in the management of sedation, analgesia, and delirium in critically ill patients with obesity. The authors have no conflicts of interest to declare.

Publication types

Dosing scalars. The study was entirely double-blinded, with the study planner responsible for management of anesthesia, propofol dose regulation, and statistical treatment of all enrolled patients. Given the similar PK parameters of etomidate to propofol, an induction dose based on LBW is recommended. At the beginning of anesthetic induction, sufentanil citrate the concentration of effector chamber was set at 0. All rights reserved.

Fentanyl is the most commonly used opioid in anaesthesia, and has a time to peak effect propofol induction dose morbid obesity 3—5 min. Morbld effects terminate within 5—10 min after stopping the infusion. Open in new tab. Sufentanil is a highly lipophilic synthetic derivative of fentanyl with a potency that is about 10 times greater. Estimating the induction dose of propofol in morbid obesity: striking a happy medium J. Estimating ideal body weight--a new formula.

Clinical and pharmacokinetic studies involving sedatives. Acknowledgements Not applicable. Weight-based dosing using ABW is discouraged because dose proportionality between pharmacokinetic parameters and ABW is rarely encountered. Similarly, pharmacokinetic studies evaluating various opioids in the perioperative setting have found opioid doses based on ABW are likely to be excessive as evidenced by pharmacokinetic parameters and measured opioid concentrations [ 171819202122 ]. Table 1 Comparison of the general conditions of the patients Full table. Pharm Res. One study evaluated the pharmacokinetics of dexmedetomidine in morbidly obese patients undergoing laparoscopic surgery [ 52 ].

As drug administration based on total body weight can result in lropofol, weight-based dosing scalars gainer blogs glorify obesity epidemic be considered. Download all slides. As a result, dosing information in package inserts is usually based on a kilogram of TBW, which can result in incorrect doses when applied to the MO patients. Doses of drugs are scaled based on the individual patient characteristics including age, weight, gender and comorbid conditions. Article Navigation.

MeSH terms

Conflict of interest. The optimal standard of the induced dose of propofol for general anesthesia in morbidly obese patients is yet to be determined. Estimating ideal body weight--a new formula.

DrugBank 5. The images or other third party material propofol induction dose morbid obesity this article are included in the article's Creative Commons pbesity, unless indicated otherwise in a credit line to the material. For the purposes of improving comparability between the two groups and eliminating the interference of sufentanil in anesthesia induction 1718all patients involved in the study were administered TCI of sufentanil citrate at a concentration of 0. Variation in postoperative analgesic requirements in the morbidly obese following gastric bypass surgery.

ALSO READ: Painful Goiter Hypothyroidism

Download all slides. There is a significant relationship between induction dose and body weight in control subjects given propofol based on TBW and MO subjects given propofol based on LBW. The use of allometric scaling to derive PK parameters is not without limitations. The inner diameter of the endotracheal intubations for male and female patients was 7. Relations of stroke volume and cardiac output to body composition: the strong heart study. Skip Nav Destination Article Navigation. Table 1 Weight-based dosing scalar recommendation for commonly used i.

Kudo S, Ishizaki T. Non-opioid analgesics commonly administered to propool ill patients typically use non-weight-based dosing regimens based on information in product literature given the lack of prospective studies evaluating weight-based regimens. Population pharmacokinetics and pharmacodynamics of brief etomidate infusion in healthy volunteers. Several assumptions or considerations underlie the recommendations in this paper. Anesth Analg. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. Covariates of intravenous paracetamol pharmacokinetics in adults.

MeSH terms

Download all slides. Google Scholar PubMed. Administering drugs based on TBW can result in pripofol overdose, while administration based on IBW can result in a subtherapeutic dose. However, the effect of BMI on desflurane uptake is not significant. However, it has also been suggested that the calculation of induced dosage based on LBW is often insufficient.

A simultaneous pharmacokinetic and pharmacodynamic evaluation. Crit Care Med. Practice guidelines provide clear evidence-based recommendations for the use of drug therapy to manage pain, agitation, and delirium associated with critical illness. Metrics details. Emerg Med J. Overall, this led to a prolonged half-life with obesity 2. Am J Health-Syst Pharmacy.

In this study, lean body weight was also used as the standard for the dosage of propofol in morbidly obese patients. Etomidate is NOT a first-line induction agent in critically ill patients: primum non nocere-above all, do no harm. Non-English articles and animal studies were not included. Table 1 Comparison of the general conditions of the patients Full table. When dosing medications, the choice of weight descriptor might seem to make little difference for weight-based dosing regimens because medications are dosed to clinical effect.

Publication types

Effect of age, gender, and obesity on midazolam kinetics. Midazolam pharmacokinetics in morbidly obese patients following semi-simultaneous oral and intravenous administration: a comparison with healthy volunteers. Adv Pharmacol San Diego, Calif. Next, recorded ABW measurements assume accuracy e. When the blood concentration of sufentanil reached a stable level, the difference between the blood pressure and heart rate of the patients was insignificant compared with when they entered the room, and so the blood pressure and heart rate of the patients could be used as the base value.

Guidelines promulgated by anesthesia associations in Great Britain and Ireland propofol induction dose the use of lean body weight for dosing opioids given the poor correlation between opioid concentrations and clinical effect and concerns related to overdosing until patients are alert allowing for dose titration [ 26 ]. Patients with preoperative mental abnormalities, long-term use of analgesic and sedative drugs, drug abuse, opioid addiction, long-term drinking history, general anesthesia contraindication, and expected airway difficulties were excluded. Peri-operative management of the obese surgical patient association of anaesthetists of Great Britain and Ireland society for obesity and bariatric anaesthesia. Performance of alfentanil target-controlled infusion in normal and morbidly obese female patients. Nevertheless, a troublesome adverse effect with haloperidol is QTc prolongation, which can be associated with dose. BIS, bispectral index. Based on pharmacokinetic studies, the relationship between ABW and pharmacokinetic variables such as volume of distribution and clearance is not linear for many medications used in the management of pain, agitation, and delirium.

Remifentanil pharmacokinetics in obese versus lean patients. Decreased fentanyl and alfentanil dose requirements with age. West J Emerg Med. Several studies have evaluated propofol-dosing strategies in the operating room but there are no data specific to the ICU. Following the propofol injection, 0. None of the patients had experienced serious cardiopulmonary disease, endocrine, liver, or kidney dysfunction, or electrolyte abnormalities before surgery. Availability of information for dosing commonly used medications in special ICU populations.

Randomized propofol induction dose morbid obesity of isoflurane and sevoflurane for laparoscopic gastric banding in morbidly obese patients. Nevertheless, this study had some limitations. For the purposes of improving comparability between the two groups and eliminating the interference of sufentanil in anesthesia induction 1718all patients involved in the study were administered TCI of sufentanil citrate at a concentration of 0. Like fentanyl, the time to peak effect is 3—5 min. Weight related quantities described in the text are plotted in kilograms against the BMI.

Declaration of interest

The decline in plasma concentration and termination of effect is because of rapid redistribution dosd thiopental to peripheral tissues. Following the propofol injection, 0. Anesth Analg ; : 57 — Alfentanil is a fentanyl derivative with about one-tenth its potency. Wash-in and wash-out curves of sevoflurane and isoflurane in morbidly obese patients.

  • For example, derangements in cardiac and respiratory function associated with MO exaggerate side-effects of anaesthetics and narrow the therapeutic window. Cardiac output is a determinant of the initial concentrations of propofol after short-infusion administration.

  • Adjusted body weight or IBW should be used to calculate doses for continuous infusions.

  • It's the front-end kinetics, doctor! No adjustment vs.

  • Katz J, Greenberg S. Being overweight or obese as a risk factor for acute liver injury secondary to acute acetaminophen overdose.

Erstad View author publications. A summary of these recommendations is listed in Fig. Etomidate is a first-line induction agent in critically ill patients. Initial studies in healthy volunteers demonstrated a significantly higher volume of distribution, even after controlling for ABW, in obese subjects 1.

ALSO READ: Body Mass Index Formula For Adults

Comparison of intravenous ketorolac at three single-dose regimens for treating acute pain in the emergency department: a randomized controlled trial. Non-English articles and animal studies were not included. Lean body weight scalar for the anesthetic induction dose of propofol in morbidly obese subjects. The study was entirely double-blinded, with the study planner responsible for management of anesthesia, propofol dose regulation, and statistical treatment of all enrolled patients. The optimal standard of the induced dose of propofol for general anesthesia in morbidly obese patients is yet to be determined.

This is likely related to the higher doses administered or the use of ABW-based dosing in the obese cohort. Standard, non-weight-based doses of quetiapine consistent obesoty that utilized in non-obese patients should be considered. A general purpose pharmacokinetic model for propofol. Based on pharmacokinetic studies, the relationship between ABW and pharmacokinetic variables such as volume of distribution and clearance is not linear for many medications used in the management of pain, agitation, and delirium. Thus, weight-based dosing using either IBW or adjusted body weight is preferred.

Publication types

Lean body weight is not a weight obeeity for estimating drug doses in morbid obesity. Bouillon TGainer blogs glorify obesity epidemic SL. Succinylcholine is a depolarizing neuromuscular blocker with a rapid onset and short duration of action. Consequently, the results obtained through this study support anesthetic induction of morbidly obese patients based on thin body weight, but the measurement range was greater than in ordinary patients. Model development.

Obesigy is currently the most commonly used induction agent for MO subjects. Following a positive reaction, the propofol dose of the next patient would be reduced by 1 grade of a propofol dose. Can J Anesth ; 60 : — 5. The influence of method of administration and covariates on the pharmacokinetics of propofol in adult volunteers. After considering the relevant evidence, we conclude that the appropriate anesthetic induction dose of propofol should be 2.

  • Oxford University Press is a department of the University of Oxford. The influence of method of administration and covariates on the pharmacokinetics of propofol in adult volunteers.

  • You can also search for this author in PubMed Google Scholar. Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • In addition, its short duration of action allows earlier resumption of spontaneous ventilation should difficulty in securing the airway be encountered. Lean body mass as a predictor of drug dosage.

  • Comparisons between the counting data groups were conducted by chi-square test.

  • Bouillon TShafer SL.

  • The dose range in this study is greater than the dose range of patients of normal body size listed in the instructions for propofol. Volume

Clin Pharmacokinet ; 44 propofol induction dose morbid obesity — Therefore, a dose of propofol up to 3. MO subjects who were administered a rapid propofol infusion based on LBW for induction of anaesthesia required similar doses and had similar times to loss of consciousness as lean control subjects who were administered propofol based on TBW Fig. It has been demonstrated in previous studies 461920 that the amount of propofol needed to induce anesthesia is underestimated due to lean body weight according to conventional instructionswhich often leads to insufficient anesthetic depth and increased risk. InThe Irish Medical Association also pointed out in its perioperative management guidelines that LBW should be used as the standard for drug dose estimation in morbidly obese patients, but pointed out that, to ensure the avoidance of an insufficient induced dose, a certain proportion of the LBW should be increased.

Article Google Scholar 2. Suggestions were then formed using the available data based on the following dose morbid obesity strategy: outcome-based studies, pharmacokinetic studies, adverse effect profiles, and physiochemical properties. Standard doses of haloperidol that can be titrated to effect are suggested. Body surface area BSA is considered the gold standard for dosing many chemotherapeutic medications and BMI is considered the gold standard for assessing obesity. World J Critical Care Med.

Introduction

Obesity epidemic, it should be noted that relatively few patients of extreme body weight served as the basis for dosing recommendations available in product labeling. Conclusion For obese patients, there is no high-level clinical evidence available to help design dosing regimens for sedation, analgesia, and delirium as recommended in critical care practice guidelines. BMC Anesthesiol. Practice guidelines provide clear evidence-based recommendations for the use of drug therapy to manage pain, agitation, and delirium associated with critical illness.

While no prospective studies are available that compare gainer blogs glorify obesity epidemic dosing of opioids in obese and ddose weight critically ill patients, prospective and retrospective studies performed in the emergency department and postoperative propocol have consistently found large variations in opioid requirements and pain control in overweight and obese patients that had no relationship to ABW [ 13141516 ]. Propofol is one of the most widely used sedatives for the facilitation of mechanical ventilation because of its quick onset and short duration of effect. Further, equations to estimate lean body mass are not reliable in critically ill patients when compared to computed tomography as the gold standard [ 9 ]. There was no difference in volume of distribution when normalized to ABW 2. Conclusion For obese patients, there is no high-level clinical evidence available to help design dosing regimens for sedation, analgesia, and delirium as recommended in critical care practice guidelines. You can also search for this author in PubMed Google Scholar.

The decline in plasma concentration and termination of effect is because of rapid redistribution of thiopental to peripheral tissues. Sign In or Create an Account. Sign In or Create an Account. Pharmacodynamics of vecuronium and atracurium in the obese surgical patient.

Therefore, administration of a drug based inductiom a TBW metric may result in overdose in an MO individual. Appropriate dosing of lipid-soluble anaesthetics in obese patients: NAP5 recommendations. Cite Cite J. Following the propofol injection, 0. The Figure 1 illustrates the relation between lean body weight and lean -scaled weight by graphing them against BMI for female patients with a height of cm. The induction dose is 0. The use of target-controlled infusion TCI delivery systems has improved the accuracy of anaesthetic drug delivery during induction and maintenance of anaesthesia.

Nevertheless, this study had some limitations. Lean body mass and allometric scaling are other size descriptors being investigated for medication dosing. However, it has also been suggested that the calculation of induced dosage based on LBW is often insufficient.

Its quaternary ammonium group makes rocuronium highly ionized, limiting its distribution outside the extracellular fluid. Studies by Janmahasatian and Friesen et al. Search Menu. Dosing scalars. E-mail: hlemmens stanford.

Endotracheal intubation was consistently performed by the same experienced anesthesiologist under visual laryngoscopy. Respiratory acidosis enhances dose morbid obesity does and this must be considered as many MO subjects present with some element of CO 2 retention. Download all slides. Model development. The pharmacodynamic effects of rocuronium when dosed according to real body weight or ideal body weight in morbidly obese patients. Furthermore, the chosen weight scalar is only half of the equation.

  • Another doctor with an unknown propofol dose judged the negative or positive reactions informed by the same criteria. For Permissions, please email: journals.

  • Furthermore, the inherent differences in the endpoints targeted with each strategy i. Given the substantial variation in opioid pharmacokinetic parameters and clinical effects that are not related to ABW, doses titrated to effect are recommended regardless of whether weight-based or non-weight-based dosing is used.

  • Lean-scaled weight: a proposed weight scalar to calculate drug doses for obese patients.

  • Drug dosing based on weight and body surface area: mathematical assumptions and limitations in obese adults.

Shortcomings related to the study setting i. Etomidate has a large volume of distribution with relatively rapid metabolism by the liver, but with plasma concentrations that are poorly correlated with pharmacodynamic measures of clinical response [ 61 ]. The initial dose in group M was set at 3. One study noted decreased clearance of active morphine metabolites in morbidly obese compared to normal weight healthy volunteers, despite normal elimination of the parent compound. Clinical pharmacokinetics and pharmacodynamics of dexmedetomidine. Although haloperidol has pharmacokinetic properties that favor distribution into adipose tissue, there are severe adverse reactions associated with large doses.

Difficult or impossible ventilation after sufentanil-induced anesthesia is caused primarily by vocal cord closure. Carbon dioxide absorbers containing barium hydroxide or soda lime degrade sevoflurane into Compound A. In addition to estimating reasonable initial drug doses, the techniques discussed by Nightingale and colleagues 10 are important in order to improve the safety and reliability of anaesthetic induction for morbidly obese patients. Doses based on IBW are recommended to avoid drug overdose in the obese.

Dosing scalars

Population pharmacokinetics of dexmedetomidine in critically ill patients. Acknowledgements Not applicable. Drug dosing based on weight and body surface area: mathematical assumptions and limitations in obese adults.

  • According to the conventional instructions, the calculation of propofol induction dosage based on TBW can lead to overdose in morbidly obese patients.

  • At the beginning of anesthetic induction, sufentanil citrate the concentration of effector chamber was set at 0. Eur J Clin Pharmacol.

  • Wash-in and wash-out curves of sevoflurane and isoflurane in morbidly obese patients. Article Navigation.

Their study showed that EC50 in Pharmacodynamics parameters of morbidly obese patients was significantly reduced dose morbid obesity with patients of normal weight, suggesting that increased brain sensitivity to propofol in morbidly obese patients. Pharmacoepidemiol Drug Saf. Few, if any of these patients however would be expected to have extreme forms of obesity. Other studies have accounted for the non-linear relationship between weight and clearance using allometric dose scalers e. Adv Pharmacol San Diego, Calif.

  • When used for propofol TCI, this model can result in higher infusion rates during maintenance of anaesthesia. None of the patients had experienced serious cardiopulmonary disease, endocrine, liver, or kidney dysfunction, or electrolyte abnormalities before surgery.

  • Clinical and pharmacokinetic studies involving sedatives. According to the conventional instructions, the calculation of propofol induction dosage based on TBW can lead to overdose in morbidly obese patients.

  • Compound A has been shown to cause nephrotoxicity in animal studies, but this has not been observed in humans.

  • For example, derangements in cardiac and respiratory function associated with MO exaggerate side-effects of anaesthetics and narrow the therapeutic window. The positive EC50 greater than the whole process of anesthetic induction was 3.

  • Yet, after administration of 0.

  • For Permissions, please email: journals. Allometry is the study of changes in the characteristics of organisms according to body size.

The medications reviewed were those listed in propofol induction dose morbid obesity from evidence-based guidelines and include the following: opioids, non-opioid analgesics, ketamine, propofol, inductoon, benzodiazepines, etomidate, haloperidol, and quetiapine. For dosing opioids, incremental dosing titrated to clinical effect with consistent use of an ideal or adjusted body weight is suggested for weight-based dosing in obese patients, particularly in patients with more severe forms of obesity e. Accessed Oct Critical care London, England.

Application of physiologic models to predict the influence of changes in body composition and blood flows on the pharmacokinetics of fentanyl and alfentanil in patients. The study process was repeated in group B. The optimal standard of the induced dose of propofol for general anesthesia in morbidly obese patients is yet to be determined. The numerical values for patients of other heights and for men will be different, but the graphs are qualitatively similar.

References

PubMed Article Google Scholar Dosing using either adjusted or ABW is suggested in patients with more severe forms of obesity e. Morbid obesity alters both pharmacokinetics and pharmacodynamics of propofol: dosing recommendation for anesthesia induction. Routine monitoring for QTc prolongation should be conducted. Drug Metabolism Disposition.

Thiopental induction doses adjusted to LBW resulted in the same peak invuction concentrations as dose adjusted to cardiac output. Desflurane has been advocated for use in MO patients because it is the least lipophilic and least-soluble volatile anaesthetic available, and theoretically has limited distribution into adipose tissue. These data suggest that administering induction doses based on LBW is appropriate. In anesthesia induction, the conditions of sufficient anesthetic depth and the stability of the cardiovascular system must be taken into account. Doses based on IBW are recommended to avoid drug overdose in the obese.

Patients who were dosed based on ABW, however, had significantly lower bispectral index values indicating a heightened anesthetic response and increased CNS sensitivity. Subramani et al. Population pharmacokinetics of haloperidol using routine clinical pharmacokinetic data in Japanese patients. The study process was repeated in group B.

Pancuronium is an aminosteroid non-depolarizing neuromuscular blocker with an onset time of 5 min and duration of effect ibduction 60—90 min after an intubating dose of 0. As MO subjects have a reduced safe apnoea time, its rapid-onset allows rapid tracheal intubation. Induction drug and outcome of patients admitted to the intensive care unit after emergency laparotomy. All procedures performed in this study involving human participants were in accordance with the Declaration of Helsinki as revised in

What is the best size descriptor to use for pharmacokinetic studies in the obese? Inhalation agents. Article Contents Declaration of interest. Allometric scaling has been used to extrapolate the PK principles of different animal species to man, and from adult to paediatric populations in humans. Desflurane has been advocated for use in MO patients because it is the least lipophilic and least-soluble volatile anaesthetic available, and theoretically has limited distribution into adipose tissue. For MO patients in particular, changes in body composition and changes in cardiac output and regional blood flow must be considered.

Dosing recommendations however are often based on strategies used in patients with obedity body habitus. Therefore, ketamine administered by continuous intravenous infusion will likely need decreases in dose over time in order to maintain the same clinical effect. Anesth Analg. All opioids are lipophilic with log P values between 1 and 2 for morphine, hydromorphone, and remifentanil and above 3 for fentanyl and sufentanil. After considering the relevant evidence, we conclude that the appropriate anesthetic induction dose of propofol should be 2.

Leslie K, Crankshaw DP. A second study evaluated midazolam pharmacokinetics in obese patients undergoing bariatric surgery [ 56 ]. Preoperative medication was not administered to any of the patients. There are no data evaluating quetiapine dosing in obese critically ill patients.

Close mobile proopofol navigation Article Navigation. It has a rapid time to peak effect of 1. In summary, when anesthesia is induced by intravenous combined anesthesia, the appropriate dose of propofol for patients with morbid obesity is 2. Another doctor with an unknown propofol dose judged the negative or positive reactions informed by the same criteria.

Search all BMC articles Search. This paper is intended to help clinicians design initial dosing regimens for medications commonly used in the management of pain, agitation, and delirium in critically ill patients with extreme obesity. References 1. Norketamine has not only about one-third the potency of the parent compound, but also has slower elimination that increases the time to reach steady state.

  • A loading dose of dexmedetomidine 0. Awareness of the pharmacology of the commonly used anaesthetic agents including induction agents, opioids, inhalation agents and neuromuscular blockers is necessary for safe and effective care of morbidly obese patients.

  • Drug dosing based on weight and body surface area: mathematical assumptions and limitations in obese adults.

  • Lean-scaled weight: dose morbid proposed weight scalar to calculate drug doses for obese patients. In this study, the dose of propofol at a sufficient anesthetic depth in group B was determined through the modified Dixon sequential method, and group M served in determining the dose of propofol to ensure the stability of the cardiovascular system, with the ultimate aim of identifying the optimal anesthetic induction dose in patients with morbid obesity.

  • Propofol is highly lipophilic, and distributes rapidly from the plasma to peripheral tissues.

Lean body weight is not a weight scalar for estimating drug doses in morbid obesity. Therefore, administration of a drug mobrid on a TBW metric may result in overdose in an MO individual. Yet, after administration of 0. In summary, when anesthesia is induced by intravenous combined anesthesia, the appropriate dose of propofol for patients with morbid obesity is 2. None of the patients had experienced serious cardiopulmonary disease, endocrine, liver, or kidney dysfunction, or electrolyte abnormalities before surgery. Neuromuscular blockers.

Endotracheal intubation was consistently performed by the same experienced anesthesiologist under visual laryngoscopy. Propofol is currently the most commonly used induction agent for MO subjects. Pancuronium is an aminosteroid non-depolarizing neuromuscular blocker with an onset time of 5 min and duration of effect of 60—90 min after an intubating dose of 0. Sign In or Create an Account. Alfentanil is a fentanyl derivative with about one-tenth its potency. In summary, when anesthesia is induced by intravenous combined anesthesia, the appropriate dose of propofol for patients with morbid obesity is 2. Issue Section:.

Google Scholar Crossref. Article Navigation. Like thiopental, cardiac output is a significant determinant of peak plasma concentration.

Prediction of clearance, volume of distribution and half-life by allometric scaling and by use of plasma concentrations predicted from pharmacokinetic constants: a morbid obesity study. Cardiac output is a determinant of the initial concentrations of propofol after short-infusion administration. Knowledge of changes in PK and PD properties that occur in MO subjects and careful consideration of the optimal dosing scalar is necessary for safe and effective administration of anaesthesia in this patient population. About BJA. Anesth Analg ; 89 : — 4. BSA is not commonly used to determine doses of anaesthetic agents. It has a rapid time to peak effect of 1.

Does vose matter? IngrandeJ. Comparison of propofol induction dose morbid obesity in ventilation caused by enflurane and fentanyl during anaesthesia. In order to avoid prolonged neuromuscular block, a pancuronium dosing regimen based on IBW is recommended. However, in a follow-up study, the same authors showed a better predictive performance of the same PK parameters when the Janmahasatian equations were used. Doses based on TBW result in a prolonged duration of action in obese vs non-obese subjects. Anesthesiology ; 89 : —

Population pharmacokinetics of dexmedetomidine propofol induction dose morbid obesity critically ill patients. Quetiapine is an atypical antipsychotic frequently considered in place of haloperidol because of a more favorable adverse effect profile. Influence of obesity on propofol pharmacokinetics: derivation of a pharmacokinetic model. Therefore, a dose of propofol up to 3. One study evaluated the pharmacokinetics of dexmedetomidine in morbidly obese patients undergoing laparoscopic surgery [ 52 ].

The study was entirely double-blinded, with the study planner responsible for management propofol induction dose morbid obesity anesthesia, propofol dose regulation, and obesiry treatment of all enrolled patients. Prediction of clearance, volume of distribution and half-life by allometric scaling and by use of plasma concentrations predicted from pharmacokinetic constants: a comparative study. Fentanyl or dexmedetomidine combined with desflurane for bariatric surgery. Anesth Analg ; : 57 —

Nevertheless, lean body weight was the preferred weight measure for dosing. Weight-based dosing using ABW is discouraged because dose proportionality between pharmacokinetic parameters and ABW is rarely encountered. In this study, the dose of propofol at a sufficient anesthetic depth in group B was determined through the modified Dixon sequential method, and group M served in determining the dose of propofol to ensure the stability of the cardiovascular system, with the ultimate aim of identifying the optimal anesthetic induction dose in patients with morbid obesity. The data suggest larger initial doses may be necessary in obese patients because of the increased volume of distribution observed in these patients. What is the best size descriptor to use for pharmacokinetic studies in the obese? On the other extreme, under-dosing is a concern if ideal body weight IBW is inappropriately used for weight-based dosing regimens, since the calculation for IBW only considers height and not excess weight.

  • Dosing scalars. Randomized comparison of isoflurane and sevoflurane for laparoscopic gastric banding in morbidly obese patients.

  • However, there are practical concerns related to etomidate vial and syringe sizes available in bedside RSI kits that may hinder timely administration of large etomidate doses based on ABW. Clearance was unaffected by ABW.

  • Sign In or Create an Account. Dong et al.

Therefore, administration of a drug based on a TBW metric may result in overdose in an Propofkl individual. It's the front-end kinetics, doctor! When propofol was administered by continuous infusion to obese subjects, apparent volume of distribution and clearance increased with increasing TBW. Administering drugs based on TBW can result in an overdose, while administration based on IBW can result in a subtherapeutic dose. Knowledge of changes in PK and PD properties that occur in MO subjects and careful consideration of the optimal dosing scalar is necessary for safe and effective administration of anaesthesia in this patient population. The study process was repeated in group B. After considering the relevant evidence, we conclude that the appropriate anesthetic induction dose of propofol should be 2.

Due to the large individual differences in propofol, the sample size was small, and subsequent studies with a larger sample size are needed to obseity propofol induction dose morbid obesity accuracy of the research results. JFB: Development of manuscript outline, literature search, literature evaluation, crafting of recommendations, manuscript preparation, and critical review. Accessed Oct Furthermore, the inherent differences in the endpoints targeted with each strategy i. Shortcomings related to the study setting i. The results of Wu et al. Population pharmacokinetics of haloperidol using routine clinical pharmacokinetic data in Japanese patients.

The Figure 1 illustrates the relation between lean body weight and lean -scaled weight by graphing them against BMI for female patients with a height of cm. According to the conventional instructions, the calculation of propofol induction dosage based on TBW can lead to overdose in morbidly obese patients. All rights reserved.

This includes targeting light sedation, use of validated assessment scales, daily sedative interruptions, spontaneous breathing trials, and delirium screening. Shortcomings related to the study setting i. Acknowledgements Not applicable. Received : 10 March

ALSO READ: Phencyclidine Psychological Effects Of Obesity

Emergence and recovery characteristics of desflurane versus sevoflurane in morbidly obese adult surgical patients: a prospective, randomized study. Thiopental induction doses adjusted to LBW resulted in the same peak plasma concentrations as dose adjusted to cardiac output. Close mobile search navigation Article Navigation. Google Scholar Crossref. These properties make it the neuromuscular blocking agents of choice in MO patients. Obese subjects require significantly more pancuronium than lean subjects to maintain constant twitch depression. Its quaternary ammonium group makes rocuronium highly ionized, limiting its distribution outside the extracellular fluid.

Standard doses of haloperidol that can be titrated to effect are suggested. Substantial lipophilicity dose morbid obesity P 3. Propofol is one of the most widely used idnuction for the facilitation of mechanical ventilation because of its quick onset and short duration of effect. Pharmacokinetic studies in healthy volunteers or individuals with psychiatric disorders have not reported significant variance secondary to weight [ 69 ]. Delirium and sedation in the intensive care unit: survey of behaviors and attitudes of healthcare professionals.

Sign In. Dosing scalars. Such a scalar has been described 2 and may be relevant in this context.

  • Its elimination depends primarily on hepatic and biliary excretion. There is reason to suggest all else being equal that safe and effective induction doses of propofol scale with lean body weight in obese patients.

  • There was no difference in volume of distribution when normalized to ABW 2. Hypothetical examples of initial doses in three male patients with different weights using ideal body weight, adjusted body weight and actual body weight.

  • After considering the relevant evidence, we conclude that the appropriate anesthetic induction dose of propofol should be 2.

Eur J Clin Pharmacol. Practice guidelines provide clear evidence-based recommendations for the use of drug therapy to manage pain, rpopofol, and delirium associated with critical illness. J Psychosom Res. A follow-up study by the same research team however concluded fat mass did not influence dexmedetomidine clearance [ 54 ]. A comprehensive, online database was consulted for drug physicochemical properties e.

J Clin Pharmacol. InThe Irish Medical Association also pointed out in its perioperative management guidelines that LBW should be used as the standard for drug dose estimation in morbidly obese patients, but pointed out that, to ensure the avoidance of an insufficient induced dose, a certain proportion of the LBW should be increased. Initial studies in healthy volunteers demonstrated a significantly higher volume of distribution, even after controlling for ABW, in obese subjects 1. The increase in volume of distribution was more than three times that found in studies involving normal healthy volunteers or patients undergoing surgery.

Body mass index is associated with dose morbid creatinine clearance by a mechanism independent of body fat distribution. Prkpofol pharmacodynamic effects of rocuronium when dosed according to real body weight or ideal body weight in morbidly obese patients. Google Scholar Crossref. Pharmacokinetics of fentanyl administered by computer-controlled infusion pump. Single-dose etomidate for rapid sequence intubation may impact outcome after severe injury. Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Sidebar1?
Sidebar2?