Use of priming principle in the induction dose requirement of propofol and its hemodynamic stability- A cross sectional study

In anesthesia propofol induction is administered at a dose of 2mg/kg as a single bolus and when given at this dose the commonest problem faced by the anesthetist is the sudden drop in the blood pressure, as the hypotensive effect of propofol is proportional to the dose and rate of administration.To study the effect of auto co-induction (priming principle) in the requirement of induction dose of propofol and the resulting hemodynamic parameters. A prospective randomized double blinded study was conducted for a period of one year in the department of anesthesia at a government medical college hospital in TamilNadu. A total of 60 patients were selected for our study and were randomly allocated into two groups of 30 each. Group A is the study group (priming) and group B is the control group (non-priming group). In the priming group, three minutes after premedication the co induction agent was administered (25% of the calculated dose of propofol) and two minutes later the patient received propofol at a rate of 30mg/10 sec until loss of vocalization was achieved. The hemodynamic parameters along with the total dose requirement of propofol and BIS values were monitored at regular intervals after induction.The mean total dose of propofol required among the priming group patients was 78.2 mg compared to the total dose requirement in the non-priming group which was 92.5 mg and the mean difference was found to be statistically significant. A statistically significant fall in the heart rate and blood pressure was observed at 1 min and 3 mins after induction in non priming group compared to priming group. By applying priming principle the induction dose of propofol was reduced by 14.25% with a good hemodynamic stability.

A COMPARATIVE STUDY ON THE TOTAL DOSE REQUIREMENTS AND HEMODYNAMIC ALTERATIONS WITH AND WITHOUT THE APPLICATION OF PRIMING PRINCIPLE AMONG PATIENTS INDUCED WITH PROPOFOL

Background:- Propofol given at standard induction dose, is known to produce haemodynamic instability, especially hypotension. Application of “priming principle” helps to reduce the total dose of propofol. Objectives:- To study the total dose requirements of propofol and peri-intubation haemodynamic stability in patients undergoing surgery under GACV when priming principle is applied. Methodology:- This was an observational study among 54 ASA I and II patients undergoing surgery under GACV, who were randomly divided into three groups of 18 patients each. All patients received fentanyl 1 mcg/kg over 30 seconds followed by propofol. Group 1 patients received the total (100%) calculated dose of propofol. Group 2 and 3 patients received 20% and 40% of the dose respectively as priming dose, and the remaining was given 30 seconds later, until there was loss of eyelash reex. The total dose of propofol given, the heart rate, systolic and diastolic blood pressures, mean arterial pressures at various time intervals before, during and after induction and intubation, and complications observed were compared and statistically analysed using SPSS 2.0. Results:- The mean induction dose of propofol was signicantly lower in the priming groups (71.7 ± 17.2mg in group 2 and 80.0 ± 17.1mg in group 3) compared to group1 (107.9 ± 8.0mg). The fall in mean arterial pressure was signicantly lower in groups 2 and 3 (p<0.05) compared to group1 at one minute post-induction. Conclusion:-Application of priming principle reduces the induction dose of propofol and is associated with better peri-intubation haemodynamic stability.

Efficacy of Priming Principle in Propofol Induction-A Randomised Controlled Trial

Introduction: Priming refers to administration of a small calculated dose of a drug before giving the total induction dose. Priming principle is well-documented with the use of non-depolarising muscle relaxants. Over the years, propofol has emerged as an effective alternative to thiopentone for intravenous induction. Aim: To evaluate whether priming with propofol reduces the total induction dose of propofol. Materials and Methods: Fifty patients with American Society of Anaesthesiologists (ASA) I and II grades, aged 18-55 years, and undergoing elective surgical procedures under general anaesthesia were randomly allocated into two groups; with 25 patients each. Patients in Control Group (CG) received calculated induction dose of injection propofol 2 mg/kg whereas patients in Study Group (SG) received 20% of total calculated induction dose of propofol 2 mg/kg as a priming dose and remaining dose after 30 seconds titrated till the loss of the eyelash reflex. The total induction dose and the associated haemodynamic parameters were noted. The data thus obtained was then analysed using Chi-square test and Student’s t-test. Results: The CG required a higher dose of inj. propofol (2.15 mg/kg) as compared with the SG (1.77 mg/kg), i.e., there was 17.43% reduction of the total dose in the SG. The preoperative baseline vitals {Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP)} in both the groups were comparable. The changes in HR, at 1 minute and 3 minutes after induction were higher in CG than SG, which was statistically significant. The MAP at 1 minute and 3 minutes after induction was higher in SG than CG and was statistically significant. Conclusion: The priming principle when applied to induction with propofol reduces the total dose requirements of propofol and reduces the hypotension that it causes, thereby proving a stable haemodynamic state.

Effect of Priming Principle on Propofol Dose Required to Induce General Anesthesia

Objective: To compare the mean induction dose of Propofol to induce general anesthesia by conventional method versus mean induction dose after applying priming principle. Study Design and Setting: Randomized controlled trial at Operation theatre complex, Shalamar Hospital, Lahore from November 2016 to May 2017. Methods: A total of 100 patients aged 18-55 years were equally divided into control and study groups. After standard anesthetic monitoring, intravenous propofol was used for induction of general anesthesia by conventional method in Control (C) group and by applying Priming principle in Study (S) group. Total dose requirement of propofol was noted. Data was analyzed in SPSS version 20 and paired sample t-test was applied. P-value of < 0.05 was considered as significant. Results: The mean induction dose of propofol was 70.90 ± 16.77 mg in study group (S) as compared to 94.60 ± 20.22 mg in the control group (C). The difference of mean induction dose in both groups was 23.7± 3.45 mg and thus p-value of 0.000. Conclusion: There was significant reduction of dose of propofol required to induce general anesthesia in elective surgical patient by applying priming principle