Optimal Opioid Analgesia in Early Postoperative Period with and without Addition of NSAIDS in Cardiac Surgery

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Introduction

Study was conducted in Latvian Centre of Cardiology of Pauls Stradins Clinical university hospital. A total of 50 cardiac surgery patients were included in the study where 28 patients were male and 22 patients were female with mean age of 70.3 years. Postoperative Visual Analog Scale (VAS) score, weight, fentanyl dose, Non-Steroidal Anti-Inflammatory Drugs (NSAID) use, effects as meteorism, breakthrough pain, nausea in 2^nd, 4^th and 6^th postoperative hour were registered. All patients received fentanyl analgesia at rate 0.2 mg/h during the first 4 hours, while some patients received NSAIDs along with fentanyl analgesia. All the patients were categorised into two groups, patients with significant pain (≥ 4 VAS) group and patients no significant pain (≤ 3 VAS) group.

Further 4^th hour significant pain patients were divided into NSAID group and no-NSAID use group where 6^th hour pain VAS score was tested. Further division into moderate pain (4-5 VAS score) NSAID and no-NSAID use group was done and 4^th to 6^th postoperative hour decrease in pain tested.

Description

Highest side effects were found in 4^th hour. The side effects included 46% of nausea, 28% breakthrough pain and 10% meteorism. Pain severity according to VAS score in 4^th hour was higher compared to 6^th hour and was significant with 4-8 VAS score in 56% of patients. It was insignificant in 44% of the patients whose VAS was 0-3. Moderate pain was observed in 30% of patients where VAS score was 4-5. VAS score with grading 6-7 comprehends to severe pain which was observed in 18% and subsequently, 8% of patients were observed to have very severe pain where the VAS score was 8. According to the Receiver Operating Characteristic (ROC) curve analysis, at the dosage of 0.2516 mcg/kg/h approximately around 78.6% of patients with pain were identified and false positive rate was found to be around 9%. According to ROC coordinates of the curve, at the dosage of 0.2516 mcg/ kg/h sensitivity was ~87% of patients with nausea and the false positive rate was ~22%. Similarly, at the dosage of 0.2800 mcg/ kg/h the sensitivity was found to be ~61%, but the false positive rate depicted very low (~3.7%).

6^th hour VAS score was significantly different in patients with NSAID use and with non-NSAID use in 4^th hour (p=0,016). In 6^th hour, VAS for patient with NSAID use median (Q1-Q3) was 2 (1-3), but with no-NSAID use median (Q1-Q3) was 1 (0.5-1.5). The VAS score difference from 4^th to 6^th hour in moderate pain was insignificant (p=0.776).

Most of common side effects encountered while conducting the study were nausea and breakthrough pain. 0.2516 mcg/kg/h of fentanyl is the optimal standard dosage regarding pain management and the point of high probability of nausea. As per physician’s advice, for standard optimal pain management, anti-emetics should be given to patient’s right at the beginning of the fentanyl therapy. VAS group in 6^th hour is significantly different in patients with NSAID use and with patients who do not use NSAIDs. In the 4^th hour both groups presenting with pain whose score of VAS was <4 and therefore was considered to provide adequate therapy. No-NSAID group showed similar results to NSAID group but consisted of only 4-5 VAS values.

Conclusion

Therefore, further evaluation should be focused on moderate pain with VAS score, 4-5 in both the groups. VAS score difference from 4^th-6^th hour in moderate pain proved insignificant, but due to the inclusion of small number of patients (small sample) and the outliers in this group, the significance can neither be proven nor ruled out. Thus, we recommend more studies with more participants for the future study.