An observational study to compare hemodynamic changes and gas exchange in volume controlled vs pressured controlled ventilation in patients undergoing laparoscopic assisted vaginal hysterectomy

After obtaining institutional ethical committee approval, obtaining patient’s informed and written consent

patients of ASA I, II, III who will be undergoing Laparoscopic assisted vaginal hysterectomy under general

anaesthesia will be recruited to participate in this prospective observational study.

After the patient arrived in operating room and applying monitors like pulse oximetry, electrocardiogram, non

invasive blood pressure monitoring, manual blood pressure monitoring, end tidal carbon dioxide monitoring all

the patients will be premedicated by 0.02 mg/kg Midazolam, 0.2mg Glycopyrolate, inj. 2% lignocaine prior to

induction. Adequate pain relief will be given by fentanyl 1mcg/kg. Induction will be carried out using Propofol 2

mg/kg, and injection succinyl choline 1mg/kg. All patients will be intubated by using endotracheal tube and

conventional laryngoscope. Patients will be put on mechanical ventilation after intubating under general

anaesthesia. Patient will be maintained on Sevoflurane at 2 minimum alveolar concentration ( fresh gas flow

2lit/min) and additional intermediate acting muscle relaxant vecuronium will be given at loading dose of

0.1mg/kg and at maintenance dose of 0.02 mg/kg. Neuromuscular blocking activity will be monitored using

Train of four, and intermediate muscle relaxant will be given only after observing 2 twitches. All the patients will be given 7ml/hour/kg Ringer lactate solution intraoperatively. Patients will be kept warm by using heated

conductive system to keep body temperature above 36 degree celcius.

All the cases for laparoscopic assisted vaginal hysterectomy will be of benign condition. The operating table will

be set to 30% Trendelenburg position and intra abdominal pressure set to 10-12 mmHg using automated

endoflatter.

Mechanical ventilator settings will be as follows- Female patients undergoing laparoscopic assisted vaginal

hysterectomy will be divided in two groups. The patients in volume controlled group will be mechanically

ventilated using volume controlled mode throughout surgery, while patients in another group will be ventilated

on volume- controlled mode initially and will be switch to pressure- controlled mode after 15 minutes of

creation of pneumoperitoneum using tidal volume 4 -7ml/kg, airway pressure will set to provide tidal volume

of 4-7 ml/kg not exceeding 35 cm H2O, inspiratory : expiratory ratio 1:2, positive end-expiratory pressure-5 cm

of H2O, initial respiratory rate 12 will be set and will be adjusted to maintain target end-tidal CO2 36 +/- 2 for

both group. Hemodynamic variables will detected by heart rate, systolic and diastolic blood pressure, mean

arterial pressure, end tidal carbon dioxide. Gas exchange parameters will be monitored by Ph, PaO2, PaCO2,

SaO2 after drawing and analysing Arterial blood sample. ventilatory parameters will be monitored by tidal

volume, peak and mean airway pressures following induction (T0), and after peritoneal insufflation at (T1)- 5

minute after pneumoperitoneum, (T2)- 10 minute after pneumoperitoneum, (T3)- 15 minutes after

pneumoperitoneum. At 15 minutes after creating pneumoperitoneum arterial blood gas sample will be

withdrawn and will be analysed immediately with blood gas analyser available at Shree Krishna hospital

laboratory.

Post operatively immediately after reversing and extubation arterial blood gas sample will be withdrawn from

patients of both group for comparison between both group of patients who received volume- controlled vs

pressure-controlled ventilation intraoperatively.