A Height – Adjusted Spinal Dosing Table for Caesarean Section

Introduction

The author has developed a height–adjusted dose of 0.5% hyperbaric bupivacaine over a number of years. Audit data has shown that, in combination with a standardised technique, using such an individualised dose produces predictable and reliable spinal blocks close to thoracic dermatome T3 at 10 minutes post – spinal injection.

Very occasionally, the block may be below T4. The block can be raised with a few degrees of head–down tilt and flexed knees, testing every minute and resuming the original position once the desired sensory block level has been reached.

No technique can claim to be 100% successful. Successful subarachnoid block is dependent on surgical, anaesthetic and patient factors. This is acknowledged in the disclaimer.

Dr Helen Brar, Consultant Anaesthetist, UHND

The Durham Tap
Table

Height (to nearest cm)	Vol (ml) 0.5% hyperbaric bupivacaine (excluding opioid)	Height (to nearest inch)
141	—	4’8″
142	1.9	4’8″
143	2.0	4’8″
144	2.0	4’9″
145	2.0	4’9″
146	2.1	4’9″
147	2.1	4’10”
148	2.1	4’10”
149	2.2	4’11”
150	2.2	4’11”
151	2.2	4’11”
152	2.3	5’0″
153	2.3	5’0″
154	2.3	5’1″
155	2.4	5’1″
156	2.4	5’1″
157	2.4	5’2″
158	2.5	5’2″
159	2.5	5’3″
160	2.5	5’3″
161	2.6	5’3″
162	2.6	5’4″
163	2.6	5’4″
164	2.7	5’5″
165	2.7	5’5″
166	2.7	5’5″
167	2.8	5’6″
168	2.8	5’6″
169	2.8	5’7″
170	2.8	5’7″
171	2.8	5’7″
172	2.9	5’8″
173	2.9	5’8″
174	2.9	5’9″
175	2.9	5’9″
176	2.9	5’9″
177	3.0	5’10”
178	3.0	5’10”
179	3.0	5’10”
180	3.0	5’11”
181	3.0	5’11”
182	3.1	6’0″
183	3.1	6’0″
184	3.1	6’0″
185	3.1	6’1″
186	3.1	6’1″
187	3.2	6’2″
188	3.2	6’2″
189	3.2	6’2″
190	3.2	6’3″
191	3.2	6’3″
192	3.3	6’4″
193	—	6’4″

The Technique

Obtain height (cm) from antenatal notes to determine volume of bupivacaine.
Confirm height with pt (feet / inches) to exclude errors in measurement / recording.
Gently pressurise 1st litre of Hartmanns solution. 2nd litre free flow.
Sitting, L3/4, no barbotage (or aspirate 0.2ml at beginning only). Allow 2 drops of CSF out from needle hub to exclude air.
Inject at approx 0.2 – 0.3ml/s, then immediately supine with left lateral tilt. Reduce dose if epidural in situ.
Phenylephrine (100ug/ml): start at 30ml/hr. Adjust and bolus to maintain baseline systolic arterial pressure.

Feedback

The author welcomes feedback and comments.

Acknowledgement

This table was developed at the University Hospital of North Durham (UHND), CDD NHS FT.

Disclaimer

This table originated from my own practice. Whilst it seems to be effective, I am unable to take responsibility for failure or any side effects.

Dr Helen Brar, Consultant Anaesthetist, UHND