Evaluation of Propofol Dosing Based on Total Body Weight Versus Adjusted Body Weight in Obese Patients Receiving Total Intravenous Anaesthesia With Automated Closed-Loop Anaesthesia Delivery System: A Randomized Controlled Study
试验速览
- 阶段
- 4 期
- 状态
- 招募中
- 入组人数
- 46
- 试验地点
- 2
- 主要终点
- Propofol Maintenance Dose (mg/kg/hour)
研究概览
简要总结
The pharmacokinetic profile of various drugs is altered in obese patients especially those administered by the intravenous route. Propofol is the commonly used intravenous anesthetic agent for induction and maintenance of anaesthesia as part of total intravenous anaesthesia (TIVA) regimen. A major concern with propofol dosing based on total body weight (TBW) in obese patients is disproportionate drug administration leading to undue drug accumulation in body with a potential to overdosing, delayed recovery from anaesthesia, and adverse hemodynamic outcome. Studies on propofol dosing based on various weight scalars have recommended that lean body weight (LBW) should be used for calculating bolus dose during anaesthesia induction and TBW or adjusted body weight (ABW) for arriving at an infusion dose required for maintenance of anesthesia. Although propofol delivery based on dose calculated by TBW has been well researched the evidence for propofol delivery based on dose calculated by ABW is lacking.
Recent advance in the delivery of propofol has been the development of computer controlled anaesthesia delivery systems. These devices deliver propofol based on patient's frontal cortex electrical activity as determined by bispectral index (BIS). Evaluation of anaesthesia delivery by these systems has shown that they deliver propofol and maintain depth of anaesthesia with far more precision as compared to manual administration. One such indigenously developed computer controlled anaesthesia delivery system is the closed loop anesthesia delivery system (CLADS). CLADS functions on control of processed EEG response parameter captured from anesthetized patients with the help of a BIS- monitor, which is continuously fed into an automated drug infusion pump. The infusion pump then accordingly delivers the anesthetic drug to the patients based on pharmacodynamic requirements. The investigators plan to evaluate the propofol maintenance dose requirement based on TBW versus ABW using CLADS for propofol delivery.
详细描述
Propofol is the most used intravenous agent for induction and maintenance of anaesthesia as part of total intravenous anaesthesia (TIVA) regimen.
In the morbidly obese, various factors, such as, increased body fat content, lean body weight, cardiac output, total blood volume, and alterations in regional blood flow; which adversely/unpredictably affect the volume of distribution, clearance and elimination of intravenous anesthetic drugs, thereby making administration of TIVA difficult to control.
A major concern with propofol dosing based on total body weight (TBW) in the obese patients is disproportionate drug administration leading to undue drug accumulation in body with potential overdosing, delayed recovery from anaesthesia, and adverse hemodynamic outcome. Studies on propofol dose regimen for TIVA recommended that LBW should be used for calculating bolus dose during induction of anaesthesia and TBW or ABW for arriving at a infusion dose required for maintenance of anaesthesia.
Propofol requirement for induction of anaesthesia is based on LBW is especially relevant for the morbidly obese patients as because their surplus fat mass increases volume of distribution of propofol, which, in the face of decreased blood flow to adipose tissue; imposes the burden of potential drug accumulation. This may result in increased drug delivery to non-adipose tissue during induction of anaesthesia and possibly leading to undesirable rarefaction of depth-of-anaesthesia and attendant adverse haemodynamic effects.
Conversely, during the maintenance phase of propofol TIVA, the volume of distribution and clearance of propofol increases and correlates linearly with TBW. In this respect, controlling propofol delivery in the morbidly obese with Eleveld allometric PK model, which utilizes TBW as weight parameter; has been found to be superior to other models that employs other weight dosing scalars.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Double (Participant, Outcomes Assessor)
盲法说明
The patient will be blinded to the type of anaesthesia intervention. The attending anaesthesiologist will however not be blinded to the technique utilized to administer GA and recovery immediately after extubation inside the OR. The postoperative patient recovery profile will be evaluated by an independent assessor blinded to the technique of GA.
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •ASA physical status II/III
- •laparoscopic and non-laparoscopic surgery of more than 60-minutes duration
- •Body mass index > 35kg/m2
排除标准
- •Cardiovascular disorders (uncontrolled hypertension, Atrio-ventricular block, sinus bradycardia, congenital heart disease, reduced LV compliance & diastolic dysfunction)
- •Neurological disorders (previous neurosurgery, psychiatric disorders, autonomic nervous system disorders- orthostatic hypotension, transient ischemic attacks)
- •Hepato-renal insufficiency
- •Uncontrolled diabetes mellitus
- •Known allergy/hypersensitivity to study drug
- •Pulmonary dysfunction (restrictive /obstructive lung disease)
- •Acute/chronic drug dependence/substance abuse
研究组 & 干预措施
Total Body Weight group
Anesthesia will be induced and maintained with Propofol administered by CLADS which will be set to deliver Propofol according to total body weight (TBW). A BIS-value of 50 will be used as the target for induction and maintaenance of anesthesia.
干预措施: Propofol (Drug)
Adjusted Body Weight group
Anesthesia will be induced and maintained with Propofol administered by CLADS which will be set to deliver Propofol according to adjusted body weight (ABW). A BIS-value of 50 will be used as the target for induction and maintenance of anesthesia.
干预措施: Propofol (Drug)
结局指标
主要结局
Propofol Maintenance Dose (mg/kg/hour)
时间窗: From start of anesthesia till 5- minutes post skin closure
Propofol required for maintenance of anaesthesia based on total body weight versus adjusted body weight
次要结局
- Intra-operative heart Rate (beats per minute)(From beginning of anaesthesia till 10 hours intraoperatively)
- Anaesthesia Depth consistency(From start of anesthesia till 5- minutes post skin closure)
- Intra-operative systolic , diastolic, and mean blood pressure (mmHg)(From beginning of anaesthesia till 10 hours intraoperatively)
- Postoperative sedation(From end of anaesthesia till 24-hours postoperatively)
- Intraoperative awareness(From the end of anaesthesia till 48-hours, postoperatively)
- Performance characteristic of propofol delivery system(From start of anesthesia till 5- minutes post skin closure)
- Early recovery from anaesthesia(From beginning of anaesthesia till 30-minutes postoperatively)
研究者
Nitin Sethi, DNB
Principal Investigator
Sir Ganga Ram Hospital