Statement of Problem

During anaesthesia induction, cervical myelopathy patients have higher risk of developing hemodynamic changes due to ANS dysfunction and can result in spinal cord ischemia. Effect of fluid pre-loading on hemodynamics in patients with chronic cervical myelopathy during anaesthesia induction is unknown. Effect of post-induction hypotension on cSO2 is also unknown.

Aims and objectives

Primary objective: To assess the effect of fluid pre-loading before induction of general anaesthesia, on the incidence of post-induction hypotension in patients with chronic cervical myelopathy

Secondary objective:

1.      To assess the effect of fluid pre-loading before induction of general anaesthesia, on the hemodynamic parameters following induction in patients with chronic cervical myelopathy

2.      To evaluate the effect of autonomic dysfunction on post induction hypotension and autonomic function changes during and following induction using the ANS index.

3.      To assess effect of hypotension on cerebral oxygen saturation (cSO2).

Study procedure

Patient details like age, sex, height, weight, BMI would be collected. Preoperative data including heart rate, Blood pressure, cardiac output, total peripheral resistance, blood oxygen saturation, ANS index, cerebral oxygen saturation would be collected using noninvasively placed patient monitors including NICOM, ANSiscope, and NIRS.

Following this patients in Group F would receive 20 ml/kg of Ringer lactate over 30 minutes prior to induction of anaesthesia, followed by 2ml/kg/h maintenance. Patients in Group C would receive Ringer lactate at 2ml/kg/h prior to induction of anaesthesia.

Standardized   anaesthetic    protocol will be followed for all patients for induction and maintenance of anaesthesia. Heart rate, Blood pressure, cardiac output, total peripheral resistance, blood oxygen saturation, ANS index, cerebral oxygen saturation would be collected before induction, at 1,3 and 5 minutes after induction, and 1,3 and 5 minutes after intubation and 5 minutes after positioning. Hypotension will be treated with mephentermine 3 mg boluses (repeated every 5 min) till blood pressure returns to normal range and documented. Other  patient  data  in  the  perioperative  period  like  duration  of  surgery,  blood loss  and  blood  transfusion  details would  also  be  collected

Anaesthesia management

Pre-oxygenation will be done with a FiO2= 1.Anaesthesia will be induced with fentanyl (2mcg/kg), thiopentone (5mg/kg), preservative free lignocaine (1mg/kg).Muscle relaxation will be achieved with vecuronium (0.15mg/kg). Intubation will be done with appropriate size endotracheal tube at a minimum alveolar concentration of 1 MAC with a gaseous mixture of O2+air+Sevoflurane

Data collection

The data collected would include the following:

Demographics

Nurick’s score for severity of cervical myelopathy

Pre-intervention HR, BP, spo2, ANS Index, CO, cSO2

Post study intervention HR, BP, spo2, ANS index, CO, cSO2

Post induction - HR, BP, spo2, ANS index, CO, cSO2

Post-intubation - HR, BP, spo2, ANS index, CO, cSO2

Post- positioning- HR, BP, spo2, ANS Index, CO, cSO2