The Effect of Perioperative Vitamin C on Postoperative Analgesic Consumption: A Meta-Analysis of Randomized Controlled Trials.

Kuo-Chuan Hung,Min-Hsien Chiang,Jen-Yin Chen,Yao-Tsung Lin,Li-Kai Wang,Shao-Chun Wu,Kee-Hsin Chen,Cheuk-Kwan Sun,Ying-Jen Chang

doi:10.3390/nu12103109

Abstract

Because the analgesic effect of vitamin C against acute pain remains poorly addressed, this meta-analysis aimed at investigating its effectiveness against acute postoperative pain. A total of seven randomized controlled trials with placebo/normal controls were identified from PubMed, Cochrane Library, Medline, Google Scholar, and Embase databases. Pooled analysis showed a lower pain score (standardized mean difference (SMD) = −0.68, 95% CI: −1.01 to −0.36, p < 0.0001; I2 = 57%) and a lower morphine consumption (weighted mean difference (WMD) = −2.44 mg, 95% CI: −4.03 to −0.86, p = 0.003; I2 = 52%) in the vitamin group than that in the placebo group within postoperative 1–2 h. At postoperative 24 h, a lower pain score (SMD = −0.65, 95% CI: −1.11 to −0.19, p = 0.005; I2 = 81%) and lower morphine consumption (WMD = −6.74 mg, 95% CI: −9.63 to −3.84, p < 0.00001; I2 = 85%) were also noted in the vitamin group. Subgroup analyses demonstrated significant reductions in pain severity and morphine requirement immediately (1–2 h) and 24 h after surgery for patients receiving intravenous vitamin C but not in the oral subgroup. These findings showed significant reductions in pain score and opioid requirement up to postoperative 24 h, respectively, suggesting the effectiveness of perioperative vitamin C use. Further large-scale trials are warranted to elucidate its optimal intravenous dosage and effectiveness against chronic pain in the postoperative pain control setting.

Highlights

Postoperative pain, which is present in up to 80% of patients undergoing surgery [1], impairs the patients’ quality of life such as sleep quality and level of activity [2] and contributes to chronic postoperative pain [3]
The findings showed that the use of vitamin C was associated with a lower risk of postoperative nausea and vomiting (PONV)
A previous study reported that intraoperative administration of vitamin C was associated with a decreased operative blood loss [28], the present study demonstrated no significant difference in blood loss between the vitamin and placebo groups

Summary

Introduction

Postoperative pain, which is present in up to 80% of patients undergoing surgery [1], impairs the patients’ quality of life such as sleep quality and level of activity [2] and contributes to chronic postoperative pain [3]. A previous study has shown that less than half of the postoperative patients reported satisfactory pain control [1]. The commonly used postoperative analgesic agents including opioids and non-steroid anti-inflammatory drugs (NSAIDs) are associated with untoward side-effects including respiratory suppression and other relatively minor complications such as nausea or vomiting [4]. NSAIDs, which are usual adjuvants to opioid-based regimens, are known to contribute to adverse gastrointestinal and nephrotic side-effects. Inadequate pain control is a common tradeoff between optimal postoperative analgesia and drug-associated side-effects [5]. In an attempt to maximize the degree of analgesia while minimizing untoward side-effects, modern practice guidelines recommend a multimodal intervention for postoperative pain control that involves a combination of different analgesics with nonpharmacological approaches [4]

Methods

Discussion

Conclusion