Use of Equilibriation point of Sevoflurane and Desflurane as a changeover point to low flow anesthesia- a randomised prospective comparative study on Breast cancer surgeries

The study is a randomised prospective comparative study between two inhalational agents and switchover to inhalational agents Preoxygenation will be done for 3 minutes with 100% oxygen at 10 litre/min. Inj. Midazolam 0.02mg/kg and Inj. Fentanyl 1mcg/kg will be given as premedications. Patient will be induced with Inj. Propofol 2 mg/kg iv. After adequacy of mask ventilation is checked, Inj. Vecuronium 0.1 mg/kg iv will be administered.

Patient will be intubated with a cuffed endotracheal tube of appropriate size and tube position will be confirmed by End Tidal CO2 (EtCO2) waveform and bilateral equal air entry confirmed by auscultation, secured and connected to the ventilator.

Ventilation will be started at FiO2 of 40-50%, with tidal volume of 7ml/kg body weight on Volume Control (VC) mode, a high fresh gas flow of 6 lts/min (in ratio 40:60, O2:N2O) with dial concentration of 1.3 times the age specific MAC with either Sevoflurane (Group A)or Desflurane (Group B) will be set. The inspired (Fi) and expired (Fe) gas concentration will be noted till a ratio of 0.8 is achieved (equilibration point).

Once the set ratio is achieved, the flow will be reduced to 750ml. Arterial blood gases and time will be noted down. Dial concentration of anesthetic agent will noted and will be changed if needed to maintain age specific MAC of 1. Patient will be maintained on Inj Vecuronium 0.025mg/kg iv. Inj Fentanyl 0.5mcg/kg iv will be given as and when need for analgesia arises.In case inspired O2 concentration fall < 40%, it will be corrected by increasing FiO2 to 55-60%.

Hemodynamic parameters like Systolic BP (SBP), Diastolic BP (DBP), Heart rate (HR) , SpO2, inspired (Fi) and expired (Fe) gas concentration of O2, N2O, Sevoflurane/ Desflurane, mean time to achieve equilibration time of the volatile agent will be monitored for every minute for the first 5 minutes followed by every 5 minutes for 30 mins and there on every 15 minutes till the time of extubation.

At the end of surgery (at the time of the completion of the last stitch) N2O and inhalational agent will be switched off. Once the reversal criteria is obtained Inj Neostigmine 0.05mg/kg iv and Inj Glycopyrrolate 0.01mg/kg iv will be given.

When extubation criteria is met patient will be extubated. Recovery time will be noted as time from discontinuation of inhalation agent to the time patient can follow verbal commands. Any critical events of occurred will be noted down and tackled. Patients will be monitored in PACU for 3 hours post-operatively.