Patients With ASA 3 Designation Clinical Trial
Official title:
A Randomized-Controlled Trial to Compare the Effect of Propofol vs. "Ketofol" on Hemodynamic Stability During Induction of General Anesthesia
The purpose of this study is to compare the hemodynamic effects of a standardized induction of general anesthesia with either propofol or ketofol in patients with physical status classification ASA 3. The study will be a double blinded, randomized controlled trial (RCT) with two arms of treatment groups. One arm will consist of induction of general anesthesia using a mixture of 1.5mg/kg:0.75mg/kg Propofol/ketamine (ketofol) and the induction dose will be 1.5mg/kg of propofol and 0.75mg/kg of ketamine; the second arm will consist of induction of general anesthesia using propofol 2mg/kg. The primary outcome of the intervention will consist of hemodynamic changes during the first 30 minutes after induction of general anesthesia.
The anesthetic agent propofol can result in hypotension when used for induction of general
anesthesia. Recent trials suggest that even a short duration of hypotension during induction
of anesthesia can adversely affect organ function and overall outcome.1 To overcome the
hypotensive effect of propofol, ketamine, which has sympathomimetic effects, has been
combined with propofol to produce a mixture labeled "ketofol", which has been used both for
procedural sedation and induction of general anesthesia. Clinical trials have shown that
ketofol can attenuate the hypotensive effects of propofol during procedural sedation or
induction of general anesthesia in patients whose physical status is 1 or 2 according to the
American Society of Anesthesiologists (ASA 1-2), i.e., healthy patients or those with
mild-moderate systemic illness.2,3 Clinically, it is important to demonstrate the efficacy
of ketofol in attenuating hypotensive effects of propofol in sicker patients, i.e., patients
with physical status ASA 3. The purpose of this study is to compare the hemodynamic effects
of a standardized induction of general anesthesia with either propofol or ketofol in
patients with physical status classification ASA 3. The study will be a double blinded,
randomized controlled trial (RCT) with two arms of treatment groups. One arm will consist of
induction of general anesthesia using a mixture of 1.5mg/kg:0.75mg/kg Propofol/ketamine
(ketofol) and the induction dose will be 1.5mg/kg of propfol and 0.75mg/kg of ketamine; the
second arm will consist of induction of general anesthesia using propofol 2mg/kg. The
primary outcome of the intervention will consist of hemodynamic changes during the first 30
minutes after induction of general anesthesia.
Baseline demographics collected for each patient will include:
1. age
2. sex
3. ASA physical status
4. Hx of HTN
5. Hx of PONV
6. Preoperative pain score
The standardized induction of anesthesia will consist of intravenous administration of
midazolam 0.04mg/kg, lidocaine 1 mg/kg, fentanyl 1-2 mcg/kg, glycopyrrolate 0.004 mg/kg, an
unlabeled pre-prepared, covered syringe which will be prepared by the Yale Anesthesia
satellite pharmacist containing either propofol 2mg/kg or a mixture propofol 1.5mg/kg and
ketamine 0.75mg/kg, the amount of which will be pre-determined based on the patient weight,
and rocuronium 0.6 mg/kg. A backup 10cc syringe of the study drug will be available as well
if the initial dose is inadequate. The choice of propofol and ketamine dosing is based on a
study cited earlier by Smischney et al in 2012 that addresses ASA 1-2 patients undergoing
induction of general anesthesia. Endotracheal intubation will take place after adequate
muscle relaxation has been determined using fade of train of four on a nerve stimulator
placed over the ulnar nerve. Additional medication to facilitate induction will be used
according to the judgment of the anesthesia provider with a backup syringe of the same study
drug. Inhalational anesthesia will be administered after confirmation of endotracheal
intubation. Treatment of hypotension will be according to the anesthesia provider. Amounts
of intravenous fluids as well as doses of vasopressor that are used during induction and in
the subsequent 30 minutes after endotracheal intubation will be obtained from the anesthesia
record.
The first blood pressure (BP) upon arrival to the operating room before any anesthetic
medications are administered will be the reference (baseline) blood pressure. BP will be
measured every 1 minute from one minute before induction until 30 minutes after endotracheal
intubation.
The primary outcome of the study will be the number of time points during which the blood
pressure was below 20% of the baseline BP. Secondary outcomes will include:
1. Severity of hypotension as determined by the gradient of each blood pressure
measurement from the baseline BP.
2. The total dosage of vasopressors administered during induction and up to 30 minutes
after endotracheal intubation
3. The total amount of IV fluids administered during induction and up to 30 minutes after
endotracheal intubation.
4. The total amount of additional medications used during induction and up to 30 minutes
after endotracheal intubation.
5. Total intraoperative as well as postoperative opioid dosage used.
6. Presence or absence of PONV and severity
7. Intraoperative prophylaxis and postoperative treatment of PONV
;
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Supportive Care