Comparative Study of Lumbar Paramedian versus Taylor Approach at Spinal Anesthesia among Indian Elderly Population

An observational, single blinded study will be done in patients undergoing spinal anesthesia for elective  lower abdominal surgery.

The approach for spinal anesthesia is decided by the consultant anaesthesiologist according to the patient’s condition, convenience of performing the procedure and experience of the consultant in performing the procedure. It is a routine procedure to select either one of the approaches by the anaesthesiologist.

Procedure- After shifting patient to the operating room, electrocardiographic (ECG) monitoring of leads II and V5, noninvasive blood pressure (NIBP) and pulse oximetry will be established and the baseline vitals will be recorded. Intravenous access will be secured in the non dominant hand and an infusion of Ringer Lactate will be started. Local anesthesia 2ml of 2% Lignocaine will be administered Patients will be administered subarachnoid block using either by paramedian in L3-L4 interspace (or one interspace above or below if this space is not well felt) or Taylor’s approach ( L5-S1 interspace) using 23 SWG Quinke Babcock needle. The drug will be administered according to the patient. The number of attempts taken, presence of adequate CSF flow, blood tinged CSF, technique of delivering local anesthetic, technique of delivering drug will be noted. The drug will be injected intrathecally over a period of 10 seconds once free flow of clear cerebrospinal fluid is obtained.

A cold alcohol swab will be used to check appreciation of temperature. Check with the cold swab will be performed every 2 minutes along the midclavicular line on both sides. The higher of the two sides will be taken as end point for this parameter. Onset of analgesia at T10 will be noted. The sensory level will be checked every 2 minutes as described above until the level does not ascend any further for 4 consecutive readings. This dermatomal level will be noted as the highest level of analgesia. Sensory level will be checked every 5 minutes thereafter till the end of 1 hour, and every 15 minutes thereafter till 2-segment regression (defined as recovery of sensory block by 2 segments from the highest level achieved in that patient) and sensory recovery (around S2- S4 segments) occur

Motor blockade will be assessed by modified Bromage scale (0-1-2-3) at similar intervals as assessment of sensory block. (0 = no paralysis, able to flex hip/knee/ankle; 1 = able to flex knee

and ankle, unable to raise extended leg; 2 = able to flex ankle, unable to flex hip and knee; 3 = unable to flex hip, knee and ankle). Motor blockade will be evaluated at 2-minute intervals till a modified Bromage score of 3 is obtained or till maximum motor blockade is achieved. This time is noted as onset of motor blockade. The time at which ankle movement returns is noted to indicate recovery from motor blockade.Success was defined as obtaining CSF in one attempt. After removing stylet, if there is presence of blood with CSF this is considered as unsuccessful attempt. Aspiration of CSF is done after CSF flow is noted and during injecting of drug in beginning, middle and end phases on aspiration CSF flow is seen is considered as successful.

The number of needle passes was defined as the number of fresh attempts done to obtain a successful subarachnoid tap. Number of needle redirections was defined as the change in the direction of the needle to obtain a successful subarachnoid tap. Duration of procedure was defined as the time from needle insertion to withdrawal. An attempt was considered unsuccessful if the operator removed the stylet and saw no CSF. Failure was considered when no CSF was obtained after 2 attempts. In case of failure in paramedian approach then patients will be given general anaesthesia. If Taylor’s approach fails then general anesthesia was given.

Immediate adverse effects postoperatively- Urinary retention

Risks: There is minor risk over minimal risk. The risks mentioned are associated with the routine procedure. No additional risks present.

1. Presence of spinal deformities, anatomical defects.

2. Elderly population is vulnerable to having varying hemodynamic levels, multiple comorbidities which will need careful monitoring of the patient.

3. Presence of different patient responses intraoperatively and their management

A) Hypotension (MAP< 60mmHg)- Increased rate of fluid administeration and or bolus dose of IV Mephentermine 3mg

B) Bradycardia ( HR<50 bpm)- Bolus dose of IV Atropine 0.6mg

C) Desaturation (SpO2 < 94%) - Supplemental oxygen ( 3-5L via Hudson mask)

 Benefits:

1. Optimize patient needs.

2)  Provide better understanding in order to use which technique on elderly patients.

3)  Determine which method is resource efficient according to practitioner expertise, cost effectiveness and hospital resources.