Echo-guided estimation of formula for paravertebral block in neonates, infants and children till 5 years

Abstract

Aims: The aim of the study was to derive a clinically useful formula for paravertebral block for thoracic, lumbar (L1) and cervical level (C6) as per the ultrasound-guided measurements in neonates, infants and children up to 5 years of age.

Settings and design: Observational study.

Methods: Seventy-five patients from 2 days to 60 months were included. Paravertebral transverse ultrasound scans at cervical (C6), thoracic (T1-12) and lumbar (L1) regions were viewed to determine the optimal insertion point and depth for performing paravertebral blocks. The lateral distance from the spinous process to the insertion point and the depth from the insertion point to the paravertebral space or reference point (point just anterior to the transverse process) were measured.

Statistical analysis: Data was analyzed using the SPSS (V 10.0) package. Preliminary data was collected with the actual values of paravertebral parameters and weight and age. Initially, Pearson Bivariate Correlation Coefficients were calculated between parameters and age and weight so as to predict paravertebral parameters with the help of weight and age. As there were statistically significant associations between parameters and age and weight, an attempt was made to predict parameters with the help of age and weight. Multiple regression method (forward) was applied by taking parameters as dependent variables and age and weight as independent variables.

Results: Age and weight correlated very well (statistically significant) with paravertebral parameters; hence, prediction (regression) equations were calculated as: Prediction (regression) equation: C6A=0.005 × wt + 0.005 × age + 1.31 C6B=0.009 × wt + 0.002 × age + 1.78 T1-12 A=0.02 × wt + 0.003 × age + 0.93 T1 to 12 B=0.03 × wt + 0.03 × age + 1.02 L1A=0.03 × wt + 0.02 × age + 0.91 L1B=0.05 × wt + 0.02 × age + 0.94

Conclusions: We could derive equations to predict the values for paravertebral blocks in centimetres at different levels in the study population.

Keywords: Formula; paediatric; paravertebral block; patients; ultrasound guidance.

Figure 1

(a) Transverse thoraxic (T6) scan of an infant. SP, spinous process; TP, transverse process; VA, vertebral arch; PD, posterior dura; NR, nerve root; SC, spinal cord; AD, anterior dura; VB, vertebral body; RP, reference point for measurement of paravertebral space; ESM, erector spinae muscle. (b) Transverse thoraxic (T6) scan of a grown up child. SP, spinous process; TP, transverse process; PD, posterior dura; SC, spinal cord; RP, reference point for measurement of paravertebral space; ESM, Erector spinae muscle; VB, vertebral body

Figure 2

Transverse scan at the C6 level of an infant. SP, spinous process; TP, transverse process; PD, posterior dura; SC, spinal cord; RP, reference point for measurement of paravertebral space; DCM, deep cervical muscles; VB, vertebral body

Figure 3

Transverse scan at the LI level of an 11-month-old baby. SP, spinous process; TP, transverse process; VB, vertebral body; IP, ilio psoas; PD, posterior dura; SC, spinal cord; AD, anterior dura; RP, reference point for measurement of paravertebral space; PSM, paraspinal muscles