Pulse Transit Time as a Predictor of the Efficacy of a Celiac Plexus Block in Patients With Chronic Intractable Abdominal Pain.

OBJECTIVE

There is no well-defined predictor of satisfactory pain relief after celiac plexus block (CPB) at the early stage of treatment. This study evaluated whether measurement of the electrocardiographic R-wave and the arrival time of the pulses at the toe pulse transit time (E-T PTT) can be an early predictor of pain response and success of CPB in patients with chronic intractable visceral pain.

METHODS

Twelve patients aged between 20 and 80 years who underwent CPB for treatment of chronic intractable cancer-related abdominal pain were included. A successful CPB was determined as a >50% decrease on the numerical rating scale measured 24 hours after the procedure. The E-T PTT at baseline and at 5, 10, 20, and 30 minutes after the injection of local anesthetic was measured as the time between the R-wave on the electrocardiogram and the peak point of the corresponding plethysmogram wave from the ipsilateral great toe. The change in the E-T PTT that was predictive of a successful CPB was analyzed using receiver operating characteristic curve analysis.

RESULTS

A CPB was successful in 9 of 12 cases; the dE-T PTT5/E-T PTT0 of the success group was 6.84%±5.04% versus 0.72%±0.78% in the failure group (P=0.021). The mean E-T PTTx differed significantly between timepoints (F=9.313, P=0.014) and between the success and failure groups (P<0.01). The best value of dE-T PTT5/E-T PTT0 indicating a successful CPB, estimated by receiver operating characteristic curve analysis, was 2.30% (sensitivity 88.9%, specificity 100%). The area under the curve was 96% (95% confidence interval, 85.7%-100%).

CONCLUSIONS

Prolongation of E-T PTT at 5 minutes after CPB correlates closely with a significant analgesic effect.