Results
Of the 82 screened patients, 18 patients were excluded (Figure 1). Two patients in each group could not be traced during follow-up in 3 months. All outcomes were analyzed with the intention-to-treat principle. The demographics and surgical characteristics between the two groups did not reveal any significant differences (Table 1). The median (IQR) intraoperative fentanyl consumption was significantly less in the lidocaine group 0(0–0) μg vs. 20 (0–30) μg in the saline group (p < 0.001).
Figure 1.
CONSORT diagram of patient recruitment
The cumulative median IV morphine equivalent consumption at 24 h postoperatively was significantly reduced in the lidocaine group than in the saline group (Figure 2). The median morphine requirement in PACU was 0 (0–1) mg in the lidocaine group compared with 2 (0–4) mg in the saline group (p = 0.003). In the surgical unit, patients consumed a lesser median (IQR) tramadol in the lidocaine group, 0 (0–0) mg compared with the saline group 0 (0–50) mg (p < 0.001). The median NRS scores at rest and during movement were significantly lower in the lidocaine group than in the saline group at all time points after surgery (Figures 3 & 4). The time to the first perception of pain was longer in those receiving lidocaine (median 30 min (15–30) compared with those receiving NS (median 10 min (0–15); p < 0.001).
Figure 2.
Total morphine equivalent for 24 h postoperatively in patients receiving lidocaine and saline. Data are presented as median and interquartile range
Figure 3.
Postoperative numerical rating pain (NRS) scores at various time points at rest. Data are median with error bars showing interquartile range. Significant difference between the groups was detected at all-time points (p < 0.05)
Figure 4.
Post-operative numerical rating pain scores (NRS) at various time points during movement. Data are median with error bars showing interquartile range. Significant difference between the groups was detected at all-time points (p < 0.05)
A significant number of patients in the saline group had PONV and needed antiemetic compared to the lidocaine group (Table 2). Postoperative sedation scores were comparable between the two groups. Postoperative quality of recovery and patient satisfaction with postoperative pain relief was better in those receiving lidocaine (Table 2). No sign/symptoms related to lidocaine toxicity were observed. One patient in the lidocaine group developed intraoperative hypotension and bradycardia which was managed with ephedrine 5 mg and atropine 0.4 mg intravenously. When assessed in 3 months after surgery, two (7%) patients in the lidocaine group developed CPSP compared to four (13%) in the placebo group (p = 0.67).
BMC Anesthesiol. 2020;20(137) © 2020 BioMed Central, Ltd.
