Low-Dose Ketamine via Intravenous Patient-Controlled Analgesia Device after Various Transthoracic Procedures Improves Analgesia and Patient and Family Satisfaction

Abstract 

Ketamine was recently shown to attenuate postoperative pain when used in combination with morphine in patients who had undergone general and orthopedic surgery. We assessed its effects in 46 patients undergoing minimally invasive direct coronary artery bypass, off-pump coronary artery bypass, or thoracotomy and correlated them with patient and family satisfaction. Patient-controlled analgesia (PCA) was available for 72 hours. One group received 2mg/bolus morphine randomly and double-blindly (group MO), and another group received 1mg morphine plus 5mg ketamine/bolus (group MK), both using IV-PCA. The patients' pain and satisfaction rates were assessed three times daily during hospitalization using a visual analog scale. Their families' satisfaction was assessed as well. Although the 3-day mean amount of morphine used by the MK patients was approximately 60% of that used by the MO patients, their levels of pain and satisfaction were better than those of the MO group. There was an inverted and statistically significant correlation between the patients' level of satisfaction on the second postoperative day (POD) and the satisfaction of their families on POD 2, 3, and 7 and the POD 3 patients' pain assessment in the MK group but not in the MO group. There were no differences in hemodynamic, respiratory, side effects, or complication rates between the groups. The conclusion is that the effects of adding a small ketamine dose to half of the standard morphine dose via IV-PCA after thoracotomy was superior to the standard morphine dose in terms of the patients' self–reported pain score and satisfaction, as well as the family satisfaction rate.