Comparing Intravenous Dexmedetomidine With Midazolam in Patients Undergoing Bronchoscopy: A Meta-analysis of Randomized Controlled Trials

To the Editor: The bronchoscope is extensively used for the examination and diagnostic inspection of a wide range of respiratory diseases. Initially, a bronchoscopy procedure typically involves the regular administration of local anesthesia with lidocaine. Patient discomfort and lack of cooperation are commonly observed during bronchoscopy procedures performed under local anesthesia. The drugs propofol, dexmedetomidine, midazolam, fentanyl, and remifentanil are administered either individually or in combination to achieve sedation during bronchoscopy. However, propofol, midazolam, fentanyl, and remifentanil have respiratory depressant properties. Some studies have shown that dexmedetomidine causes less respiratory depression compared with other sedatives. To date, no published studies have performed a quantitative comparison of the efficacy and safety of dexmedetomidine in flexible bronchoscopy. We conducted a meta-analysis on randomized controlled trials (RCTs) to evaluate the effectiveness and safety of dexmedetomidine versus midazolam during bronchoscopy. The RCTs between dexmedetomidine injection and midazolam in bronchoscopy were searched from PubMed, Embase, and Cochrane Central databases. Two researchers conducted separate searches for articles, collected data, and assessed the quality of the studies. The meta-analysis used a random-effects model to analyze the data. For dichotomous outcomes, we estimated relative risks (RRs) with 95% confidence intervals (CIs). In addition, for continuous outcomes, we calculated the weighted mean differences (WMDs) with 95% CIs. Statistical heterogeneity was assessed using the I2 statistical test and χ2 test on Cochran Q statistical test. Interstudy heterogeneity was defined as an I2 > 50% or a P < 0.05. A two-tailed P < 0.05 was considered to be statistically significant. All statistical analyses were performed using RevMan 5.3 software (The Nordic Cochrane Centre, Copenhagen, Denmark). Six RCTs and 652 patients were included in this meta-analysis. The basic characteristics of the included studies are presented in Table 1. The duration of operation did not significantly differ between dexmedetomidine and midazolam during bronchoscopy (WMD = 0.74, 95% CI, −0.73 to 2.21, P = 0.3; I2 = 43%). Similarly, there were no significant differences on the dose of instilled lidocaine in patients undergoing flexible bronchoscopy (WMD, 0.04; 95% CI, −4.67 to 4.76, P = 0.96; I2 = 0%). The dexmedetomidine group exhibited a significant reduction in desaturation events during bronchoscopy (RR 0.80; 95% CI, 0.62–1.02, P = 0.9; I2 = 0%); dexmedetomidine demonstrates a higher incidence of bradycardia (RR 5.51; 95% CI, 2.82–10.76, P = 0.43; I2 = 0%) during bronchoscopy in comparison with midazolam. Table 1. - Basic characteristics of the included trials. Study Country Group Number, n Age, yr Female (n) Body weight, kg Methods Surgery Goneppanavar et al1 India DEXMDZ 2727 49.70 ± 13.8552.52 ± 15.05 7 (27)3 (27) 53.26 ± 10.1052.52 ± 15.05 1 μg/kg dexmedetomidine0.02 mg/kg midazolam Flexible bronchoscopy Kim et al2 Korea DEXMDZ 4854 63.7 ± 11.363.9 ± 11.0 15 (48)15 (54) — 0.25 μg/kg dexmedetomidine over 10 min, maintenance was 0.25–0.75 μg/kg per hour0.05 mg/kg midazolam EBUS-TBNA Kumari et al3 India DEXMDZ 9998 44 ± 1449 ± 14 43 (99)48 (98) 63 ± 1365 ± 13 1 μg/kg dexmedetomidine +1 μg/kg fentanyl2 mg midazolam +1 μg/kg fentanyl EBUS-TBNA Liao et al4 China DEXMDZ 9998 58.5 ± 9.160.1 ± 8.4 38 (99)36 (98) 57.0 ± 8.458.2 ± 11.3 1 μg/kg intravenous dexmedetomidine over 10 min, maintenance was 0.5 μg/kg per hour2 mg midazolam Flexible bronchoscopy Magazine et al5 India DEXMDZ 2727 47.07 ± 13.4045.00 ± 14.26 8 (27)13 (27) 53.23 ± 8.6950.37 ± 9.84 0.5 μg/kg dexmedetomidine0.035 mg/kg midazolam Flexible bronchoscopy Magazine et al6 India DEXMDZ 2424 48.50 ± 13.13844.42 ± 12.047 11 (24)14 (24) 50.55 ± 10.2050.07 ± 7.81 0.75 μg/kg dexmedetomidine0.035 mg/kg midazolam Flexible bronchoscopy Values are presented as number (%) or mean ± SD.DEX, dexmedetomidine; EBUS-TBNA, endobronchial ultrasound-guided transbronchial needle aspiration; MDZ, midazolam. In conclusion, dexmedetomidine is safer than midazolam as a medication for patients having bronchoscopy with topical airway anesthesia. However, it is crucial to acknowledge the potential adverse impact of dexmedetomidine on heart rate reduction during bronchoscopy procedures.