functional testing, Cortical mapping, which requires patient to be awake.^(1,2) Main advantage of awake surgery is to define limits of resection & avoid Postoperative neurological deficits.

Maintaining patient’s cooperation by provision of optimal analgesia, sedation, anxiolysis and comfortable position, achieving homeostasis with safe airway, adequate ventilation and hemodynamic stability, Ensure minimal interference with electrocortico graphic recording during mapping.

Main Objective of the study was to access Brain mapping by NRS scale, Haemodynamic Stability, & adverse effects with both study drugs dexmedetomidine or propofol.

MATERIALS AND METHODS

This Randomised double-blind comparative study of 50 adult elective patients with mass near the eloquent area with ASA grade I & II, Age group 18 to 60 years were selected for awake craniotomy. Patients were informed in detail about procedure. Proper counselling of each patient was done VS hospital, NHLM medical college, Ahmedabad, Gujarat, India

Preoperative Assessment

Through preoperative assessment & psychological counselling was done day before surgery.

Group Allocation

Group Allocation was done by using Randomisation table.⁽³⁾

Allocation concealment done by sealed opaque envelope. Envelope was opened just before General Anaesthesia administration to the patient.

Sample Size

The sample size for the study was taken for convenience.

Premedication

It was given in form of Inj. Glycopyrrolate 0.04 mg/kg, Inj. Ondansetron 0.08 mg/kg, and Inj. Fentanyl were given Intravenously.

Benzodiazepine premedication was avoided because of its residual sedative and amnesic effects during intra operative assessment phase.

Pre-Oxygenation

O2 mask was applied with O₂ flow 4 L/min. Urinary catheter was inserted for patients comfort for long operative procedure and for diuretic administration. INJ. Cefazolin 1 gm was given for infection prophylaxis.

Scalp Block

It was given by using Ropivacaine 0.5 %.30 ml (max.) to block supraorbital, supratrochlear, zygomaticotemporal, Auriculotemporal, greater & lesser occipital, greater auricular nerves for better analgesia & perioperative Haemodynamic stability. Patients were managed by ASLEEP AWAKE ASLEEP technique in following manner.

Induction

Patients were induced by Inj. thiopentone 5 to 7 mg/kg intravenously.

Airway Security

After induction, 2nd generation LMA (i-gel) of appropriate size was inserted, cuff inflated, bilateral air entry checked and after confirming air entry i-gel was fixed.

Mode of Ventilation

1. Patients were put on spontaneous plus assistance mode on ventilator Of Dragger Fabius GS work station
2. With i-gel EtCO2 sample line was attached to monitor EtCO2 intra operatively.

Patients were maintained by (A sleep Period)

By i-gel 02 (2 L/min) + N20 (2 L/min) + Sevoflurane (0.5-2%) was started.

Maintenance was Different in Both Groups-

• In-Group A - Propofol infusion was started with loading dose of 6 mg/kg/hour over 10 min, followed by 4 mg/kg/hour
• In Group B - Dexmedetomidine infusion was started with loading dose of/kg over 10 min. followed by 0.5 mcg/kg/hour.

Position

Patients were positioned in Right or Left Lateral position according to site of lesion in Sujita frame.

Sniffing position was achieved to help facilitate and patent airway. A tent was made under the drape to allow direct communication with patients when mapping was done & they were awake.

Intra Operative Period: (Awake Period)

After position, operation was started, perioperative Haemodynamic, respiratory, EtCO2, , SpO2 monitoring done periodically with interval of 15 mins and surgeons were told to inform 15 min before the craniotomy was expected to over, all inhalational agents were stopped in both groups, i-gel was removed and nasal prongs applied for oxygenation. At the end of prongs ETCO2 line (Side arm) was attached. In awake phase patients were oxygenated by nasal prongs. Sedation was managed in following ways: During awake phase patients were managed in different ways.

• In Group A (Propofol group) infusion was decreased to 2 mg/kg/ hour.
• In Group B (Dexmedetomidine group), it was decreased to 0.3 mcg/kg/hr.

In both groups, within 15 minutes after stopping inhalation agent patients were awake, conscious, and comfortable, i-gel was removed & nasal prongs were applied for oxygenation. Patients were put on nasal prongs with 02 flow rate of 3 l/min.

Perioperative Haemodynamic respiratory variables noted periodically in form of HR, Mean Arterial pressure (MAP), SPO2, ETCO2.

Peroperative awareness was assessed by PRST score (Pressure, Heart Rate, Sweating, Tears in each parameter there is sub score of 0, 1, 2)0-4 score is good as patient has depth of anaesthesia, >4 grade suggest awareness. BIS was only available for 5 patients of group B & 5 patients of group A technique. It was managed between 60-70.⁽⁴⁾

Rescue fentanyl 50 mcg was given for further analgesia. After patients were fully awaked, when neuro surgeon performed speech testing and cortical mapping (language, motor tone of limbs, speech testing). Motor strength was tested by asking patients to move their fingers, dorsiflexion of toes against resistance. Patients advised to note change in sensation. Language was tested by asking patients to count or name list of objects & observe their speech arrestor hesitation.

Cortical Mapping⁽¹⁾

• It was done according to NRS scale. NRS scale of 0 is worst mapping, & 10 is excellent. NRS scale >7 was considered satisfactory.
• Patients were watched for adverse reactions like convulsion, respiratory depression, tight brain at the site of operation, hypercapnia, and bradycardia, Nausea, Vomiting.

After Mapping: (Asleep Period)

• Patients were asleep in both groups in following manner Without i-gel. (Dose of both study drugs increased to make patients asleep for closure of craniotomy)
• In group A Propofol Infusion was increased to 4 mg/ kg/ hour
• In group B Dexmedetomidine infusion was increase to 0.5 mcg/kg/hr
• After the resection of tumour remaining surgery was conducted with same rate. At the end.
• At timeline of skin closure, Dexmedetomidine/ Propofol infusion was stopped.

Postoperative Monitoring of Recovery

• It was accessed with Modified Aldrete score. (MAS)⁽⁵⁾
• When patients in both groups MAS of more then 7 they were shifted to postoperative recovery ward.
• Post operative course of patients was noticed in form of vitals, complications, mean hospital stay in days. Patient satisfaction score (Satisfactory, Good, Excellent), surgeon satisfaction score (Satisfactory, Good, Excellent) were noticed by Linkert scale.

Primary Outcome

It was ability to perform cortical Mapping.

Secondary Outcome

It was complications, patient satisfaction score, surgeon satisfaction score regarding Anaesthesia technique.

Statistical Analysis

• Observations were entered into Microsoft Excel, & analysed by SPSS SOFTWARE 16(IBM, Arnmonk, NY, USA)
• Data were expressed as mean, range, standard deviations. Categorial data were expressed as their measures (no., N, %).
• Unpaired t test used for Numerical values.
• Chi - square test, was used for assessment of categorical data.
• p>0.05 is non-significant (NS)
• p<0.05 is significant(S).
• p<0.001 is highly significant (HS)

RESULTS