Background Local anesthetic wound infusion catheters are increasingly used postmidline laparotomy to reduce pain and opioid use, however there is little evidence to support any particular infusion regime.
Methods A retrospective cohort study was undertaken of patients after midline laparotomy who had bilateral local anesthetic wound infusion catheters surgically placed. Patients were recruited into 3 cohorts: ropivacaine 0.2% 5–8 mL/hour continuous wound infusion, 10 mL programmed intermittent bolus 2 hourly, 20 mL programmed intermittent bolus 4 hourly. The primary outcome was the maximum daily Numerical Rating Pain Score with movement (dynamic pain score) recorded during first 96 hours postprocedure. Secondary outcomes included the maximum daily resting pain score and opioid utilization.
Results In three cohorts of 70 patients (n=210), the maximum daily dynamic pain score in the intermittent bolus 2-hourly and 4-hourly cohorts was lower when compared with the continuous infusion group over the first 4 postoperative days. The mean difference in maximum daily pain score with respect to the continuous infusion regime was 0.8 (95% CI 0.2 to 1.4) for the intermittent bolus 2-hourly group and 0.6 (95% CI 0.0 to 1.2) for the 4-hourly group. Generalized estimating equation modeling indicates the reduction in dynamic pain score is greatest with the intermittent bolus 2-hourly regime over the first 72 hours postprocedure. The 2-hourly intermittent bolus regime was also associated with lower opioid utilization and local anesthetic exposure.
Conclusions Intermittent wound infusion catheter infusion regimes were associated with lower maximum daily dynamic pain scores, although the magnitude of this change may be of limited clinical significance.
- postoperative pain
- pain management
- acute pain
Data availability statement
Data are available on reasonable request. De-identified participant data are available on reasonable request. Pending approval by our local human research and ethics committee.
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Contributors JP: study design, protocol development, ethics submission, data collection, data analysis/synthesis, manuscript draft preparation, approval of final manuscript and guarantor. KB: planning of data analysis, data analysis/synthesis/presentation, manuscript review/editing, approval of final manuscript. AB: study design, protocol development, ethics submission, data analysis/synthesis, manuscript review/editing, approval of final manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.