The relationship between pain and the incidence of delirium in patients undergoing cardiac surgery

Background and Objective: Delirium has a high prevalence after cardiac surgery. Many studies were conducted on the etiology of delirium after the cardiac surgery, but its definitive reason has not expressed. Because the high percentage of these patients experience severe pain, this study was conducted to determine the relationship between pain and the incidence of delirium in patients undergoing cardiac surgery.

Materials and Method: This descriptive-analytical study was conducted on 40 patients undergoing cardiac surgery in one of the educational hospitals in Tehran in 2014. Patients were selected through convenience sampling. The incidence of delirium in patients was assessed twice daily on the second to fifth day after surgery through the CAM-ICU scale (Confusion Assessment Method -ICU). Also pain was assessed on the second post-operative day in two times, during the rest and during the nursing procedures through the Critical Care Pain Observation Tool (CPOT) in intensive care unit. Data were analyzed by using SPSS 16 and through the chi-square and Fisher's Exact Test, Mann-Whitney and McNemar test.

Results: Incidence of pain and delirium after the cardiac surgery was 95 and 45 percent respectively. 2.5 percent of patients experienced pain during rest and delirium together, while 20 percent of patients had suffered from delirium and pain during the nursing procedures. According to Fisher's Exact Test, this relationship was not significant, but there was significant relationship between some indicators of pain such as body movement (p=0.008) and muscle tone (p=0.02) with incidence of delirium.

Conclusion: According to the results, there is no relationship between pain and incidence the delirium. Due to high levels of pain and delirium, it is proposed to implement the nessecary actions for reducing the incidence of these complications.