Propofol is an intravenous anesthetic agent used for both the induction and maintenance of general anaesthesia. The aim when using propofol in this way is to infuse it at a suitable rate, with additional boluses as needed, to achieve an effective blood concentration that corresponds to the level of surgical stimulation. Various methods, such as Manual Controlled Infusion (MCI) and Target Controlled Infusion (TCI), have been suggested for delivering propofol in Total Intravenous Anaesthesia (TIVA). 

 MCI involves an anaesthesiologist manually operating the infusion pump by setting a flow rate based on the prescribed dose and the patient’s condition. The McFarlan method is commonly used, involving an induction dose of 2.5 mg/kg followed by maintenance doses that vary over time: 15 mg/kg/hr for the first 15 minutes, 13 mg/kg/hr from 15-30 minutes, 11 mg/kg/hr from 30 minutes to 1 hour, 10 mg/kg/hr from 1-2 hours, and 9 mg/kg/hr for 2-4 hours

 TCI uses a theoretical approach described by Kruger-Thiemer to achieve and maintain a steady-state concentration of a drug with pharmacokinetics described by a multicompartmental model. the Pedfusor model is used to maintain a Cp value of 4-8 mcg/ml initially, followed by adjustments according to the needs of the surgery and response to stimuli.

In this study children undergoing infraumbilical surgeries who receive general anaesthesia with caudal epidural/regional anaesthesia will be observed. Nil by Mouth (NBM) status assessed. The child is taken to the operating room (OT). Standard ASA monitors are attached, and an initial reading of all parameters is noted. Fentanyl (2 mcg/kg) is administered through a patent IV line. After tying a tourniquet proximal to the IV-line, 1 mg/kg of preservative-free lignocaine is given. The tourniquet is then released. Anaesthesia is induced 5 minutes after administering fentanyl using the intravenous induction agent propofol, either through a TCI Pedfusor model or an MCI pump.

No neuromuscular blocking agent is given. When the appropriate depth of anaesthesia is achieved, a supraglottic airway device (SGAD) is inserted, and any response to the SGAD is noted. The patient is then connected to assisted mode ventilation with appropriate fresh gas flow (O2 + air), a tidal volume of 5-7 ml/kg, and a respiratory rate according to age. Age-appropriate regional block is administered following all aseptic precautions. Infusions are stopped, and the child is allowed to remove the SGAD.

Parameters to be assessed:

• Preoperative vitals (HR, SBP, DBP, SPO2)

 • Post induction vitals (HR, SBP, DBP, SPO2)

• Total Propofol dose in mg/kg/hr including the initial bolus given in MCI Induction

 • Quality of anaesthesia (number of boluses given and no of times the infusion rate has been changed as a result of patient’s response to stimuli and hemodynamic changes)

 • Recovery

• Ease of usage as per Anaesthesiologist (Excellent, good, fair poor)

 • Satisfaction of quality of anaesthesia as per surgeons (excellent, good, fair, poor)

• Need for additional inhalational or intravenous anaesthesia agent