The role of intercostal cryoanalgesia in post-thoracotomy analgesia

Patients undergoing thoracotomy were studied to compare the effects of cryoanalgesia, combined with intravenous patient-controlled analgesia (IVPCA), against IVPCA alone during the four days following surgery. Fifty patients were randomized into two groups: an IVPCA group (n = 25) and an IVPCA-cryo group (n = 25). Subjective pain intensity was assessed on a verbal analogue scale at rest and during coughing. The intensity and the incidence of post-thoracotomy pain, numbness, epigastric distension and/or back pain, the analgesic requirements, as well as the blood gas values and respiratory function tests were evaluated up to the second postoperative (postop) month. Haemodynamic data and episodes of nausea and/or vomiting were recorded over the four postop days. In the cryo group there was a statistically significant improvement in postop pain scores (P = 10(-4)), reduction in consumption of morphine (P = 10(-4)) and other analgesics (P = 10(-4)), optimization (less acidosis) of the pH values of blood gases (P < 0.015 over 72 hours postop and P < 0.03 on the first and second postop months), increase in systolic blood pressure (P < 0.05 over 96 hours postop), reduction in heart rate (P < 0.05 over 96 hours postop), increase in values of FEV1 (P < 0.02) and FVC (P < 0.05) at the first and second postop months, reduction in the incidence of nausea (0.05 < P < 0.1 over 18 hours postop), numbness, epigastric distension and back pain (P < 0.05 at days 5, 6, 7, 14, 30 and 60 following surgery). We suggest that cryoanalgesia be considered as a simple, safe, inexpensive, long-term form of post-thoracotomy pain relief. Cryoanalgesia effectively restores FEV1 values at the second postop month.