Prevención del dolor agudo postoperatorio en cirugía oncológica de mamacomparación de opioides versus ketamina como analgesia intraoperatoria

Abstract

OBJECTIVES The main objective is to assess whether IV ketamine as an intraoperative analgesia basis decreases the incidence of acute postoperative pain (APP) as compared to the use of opioids, in patients undergoing breast cancer surgery. In the presence of APP, the purpose was to determine if its intensity is lower when ketamine was administered with respect to opioids, and in turn, to quantify the need for analgesic rescues during their stay in the Reanimation Unit and 24 hours after the intervention. On the other hand, we assessed the quality of the awakening as well as the anaesthesia safety while checking the recovery time after general anesthesia, the incidence of postoperative nausea and vomiting (PONV) and respiratory complications, comparing both groups. MATERIALS AND METHODS This is a descriptive study carried out from May to December 2017 at the Hospital General Universitario Santa Lucia de Cartagena (HGUSL). Ninety patients aged between 18 and 95 years, ASA I-III with a diagnosis of breast cancer, scheduled for oncological surgery were recruited. These patients were allotted following the usual clinical practice of each anesthesiologist in two groups, the opioid group used fentanyl at 1 - 2 ¿Êg/kg followed by a continuous infusion of remifentanil 0.01 - 0.3 ¿Êg/kg/min and a bolus of morphine at 0.05 mg/kg diluted to 10 ml of PS, before extubation, and the other one, the ketamine group performed an anesthetic induction with IV ketamine at a dose of 0.25 mg/kg and maintenance with continuous ketamine infusion at 2 - 10 ¿Êg/kg/min, in addition to a bolus of 10 ml of physiological saline (PS), to keep the observer blind,. The presence of complications after extubation was assessed, as well as its subjective quality. Subsequently, the Reanimation Unit recorded both the presence and intensity of pain -using the Numerical Pain Scale (NPS)- as well as the need for analgesic rescue at 10, 60 and 90 minutes. On the other hand, vital signs were recorded, as well as possible side effects attributable to ketamine or opioids. And finally, 24 hours after surgery, the presence of pain, the analgesic level and the need for rescues at the hospital ward were again recorded. RESULTS The results show that IV ketamine administration during intraoperative breast cancer surgery is more effective for the prevention of APP than the use of opioids. In all the measured time intervals, the IV ketamine group presented less pain than the opioid group (p < 0.05). The reduction was 83.1 % 10 minutes after extubation, 78.8 % 60 minutes, 82.4 % 90 minutes and 97.3 % 24 hours after surgery. Pain quantification using NPS (from 0 to 10) reflected lower scores in the ketamine group at 10 minutes (1.07 vs. 2.61), at 60 minutes (3.29 vs. 1.37), at 90 minutes (1.46 vs. 0.73) and 24 hours after surgery (1.88 vs. 0.13), with p < 0.05. Regarding rescue analgesia requirements 24 hours after surgery, mainly with NSAIDs (44.1 % rescue with NSAIDs vs. 2.4 % with morphine, p = 0.037), these were lower for the IV ketamine group (p = 0.005) than for the opioid group (29.3 % vs. 3.3 %). However, these differences were not observed during their stay in the Reanimation Unit, since both groups required rescue analgesia in a similar way (46.3 % opioid group versus 36.7 % in ketamine group), being necessary the administration of morphine (18.9 % with NSAIDs vs. 64.1 % with morphine, p = 0.635), and therefore there are no significant differences between groups (p = 0.635). CONCLUSIONS Parenteral ketamine in the aforementioned doses and compared with opioids, decreases the incidence of APP in breast cancer surgery, also demonstrating a decrease in the pain intensity when it appears. The need for analgesic rescue in hospitalization is more frequent in the opioid group. No significant side effects were observed, therefore it should be considered a safe anesthetic practice for this type of patients.