Effect of effort pain after upper abdominal surgery on two independent measures of respiratory function.

STUDY OBJECTIVE

To determine how effort pain interacts with changing pulmonary function after upper abdominal incisions.

DESIGN

Prospective, case-controlled study.

SETTING

Academic teaching hospital.

PATIENTS

34 ASA physical status I, II, and III patients recovering from elective, major incisional, upper abdominal surgery.

MEASUREMENTS

Manometry (maximal inspiratory and expiratory pressure) and spirometry (forced vital capacity, forced expiratory volume during the first second, peak expiratory flow) for three postoperative days. Pain scores (Visual Analog Pain Scale; VAS) at rest and after the manometric or spirometric efforts.

MAIN RESULTS

Effort pain during either manometry or spirometry was greater than pain at rest on the first postoperative day. Maximal respiratory pressure concomitantly recovered with pain during daily efforts (slopes: -0.429 and -0.278% max/mm VAS; P < 0.05). Spirometric measurements showed minimal improvement.

CONCLUSION

The direct relationship between resolution of pain with effort and direct measures of respiratory muscle effort using manometry, but not those obtained less directly by spirometry, suggests that assessing interactions between pain and effort requires a direct, quantifiable measure of effort.