Dexmedetomidine as an Adjuvant to Ropivacaine in Thoracic Paravertebral Block: A Systematic Review with Meta-analysis

Introduction

Video-assisted thoracoscopic surgery (VATS) is increasingly preferred over open approaches due to less invasiveness and faster recovery; nevertheless, postoperative pain remains clinically important. Despite that, postoperative pain from VATS is still concerning as it may be severe, especially during coughing and movement, leading to complications such as hypoventilation and delayed mobilization [¹,²].

On the other hand, Effective pain control is still a critical issue for successful outcomes. Regional anesthesia techniques, particularly the thoracic paravertebral block (TPVB), have been widely employed in thoracic surgeries to offer focused, better, and dependable analgesia; however, its short duration is still a concerning matter [³,⁴].

Ropivacaine, a long-acting local anesthetic, is commonly used for TPVB due to its favorable safety profile and low cardiac and central nervous system toxicity. Despite its benefits, ropivacaine alone may have a short analgesic duration, prompting the development of supplementary drugs to improve and prolong its action [⁵].

At the same time, dexmedetomidine, a selective alpha-2 adrenergic receptor agonist, has shown promise when used in conjunction with local anesthetics in regional anesthesia to prolong its effects. Its analgesic, anxiolytic, and sympatholytic characteristics seem to help enhance postoperative outcomes. The use of dexmedetomidine as an adjuvant to ropivacaine in TPVB has gained popularity due to its ability to prolong sensory blocking, minimize narcotic needs, and enhance overall pain control [³,⁴].

Several randomized controlled trials investigated this combination in thoracic procedures, resulting in multiple observations: indicating improved early postoperative pain scores, a longer duration to initial rescue analgesia, and lower intraoperative and postoperative opioid use. When we take those factors at suitable levels, these advantages appear to be within our scope without significantly increasing the risk of side effects such as bradycardia or hypotension [¹,⁵,⁴].

Research suggests that the combination of dexmedetomidine and ropivacaine in TPVB may affect both the acute and long-term pain outcomes significantly as the patients who received this combination experienced less pain while movement and coughing within the first 24 hours following surgery, which is clinically significant in thoracic situations where respiratory effort is essential for recovery and most of the time is a crucial factor to be put into consideration [⁶].

When we compare this to ropivacaine alone or other adjuvants, this pathway may result in increased patient satisfaction and more stable hemodynamic profiles. Despite encouraging findings, the therapeutic use of dexmedetomidine in TPVB is still diverse, with variations in doses, injection procedures, and evaluation metrics reported in our literature [⁷,⁶].

A systematic review of the current evidence is needed to determine the analgesic advantages, safety profile, and best use conditions for dexmedetomidine when combined with ropivacaine in TPVB for VATS procedures. The purpose of this review is to analyze the impact of this combination on postoperative pain control, time to rescue analgesia, and other factors. This review aims to provide a deeper understanding of whether dexmedetomidine offers a consistent and clinically meaningful advantage in enhancing thoracic paravertebral block outcomes by analyzing high-quality clinical data.

Methodology

We followed the Preferred Reporting Items of Systematic Reviews and Meta-Analysis (PRISMA statement) guidelines when reporting this manuscript [⁸]. This work was conducted in adherence to the Cochrane Handbook of Systematic Reviews of Interventions [⁹]. This study was prospectively registered in PROSPERO on 19 August 2025 (CRD42025111878).

Screening and study selection process

We used Rayyan for semi-automated screening of the literature search results according to our prespecified PICO. Studies were screened in two phases. The first phase was title/abstract screening to identify potentially relevant clinical studies. In the second phase, we retrieved the full-text articles of the selected abstracts for further eligibility screening.

Screening was conducted independently by three review authors (MA, AH, and AE). Any conflicts were resolved through discussion between the three reviewers.

Result

Study characteristic

The meta-analysis included five randomized controlled trials [⁷,¹⁰,⁶,³,⁴] evaluating the combination of dexmedetomidine and ropivacaine (PRD) versus ropivacaine alone (PR) in thoracic surgeries. The sample populations were comparable across studies in terms of age, gender distribution, and height, weight, and ASA physical status classification. The mean age of participants ranged from 19.0 to 59.5 years in the intervention groups and from 19.0 to 59.2 years in the control groups. Both groups had a relatively balanced gender ratio, although one study (Hong 2019) included only male participants Table 2 Table 1.

Table 1

Baseline characteristics of the included studies

Variable	Group	Jianghui Xu 2017	Jun Zha 2021	Zheping Chen 2024	Rong Tang 2025	Boohwi Hong 2019
Age (mean ± SD)	Intervention	59.5 ± 9.7	48.1 ± 1.5	55.43 ± 11.68	56.23 ± 8.76	19.33 ± 3.87
	Control	59.2 ± 9.7	47.1 ± 1.7	53.67 ± 8.38	58.40 ± 6.89	19.67 ± 3.1
Gender (M/F)	Intervention	18/12	—	27/23	16/14	33/0
	Control	17/13	—	19/34	15/15	33/0
Height (cm)	Intervention	167.1 ± 9.3	164.6 ± 1.4	165.83 ± 7.63	166.73 ± 9.23	173.67 ± 6.74
	Control	164.3 ± 7.6	165.9 ± 1.2	164.67 ± 7.62	166.53 ± 7.87	172.63 ± 8.99
Weight (kg)	Intervention	61.2 ± 7.5	72.4 ± 2.1	65.67 ± 9.16	65.76 ± 7.85	58.2 ± 8.0
	Control	61.2 ± 11.2	67.3 ± 2.3	66.83 ± 9.53	65.67 ± 7.72	57.8 ± 8.1
BMI (kg/m²)	Intervention	—	24.1 ± 0.6	24.03 ± 2.67	—	19.2 ± 2.2
	Control	—	23.4 ± 0.6	25.3 ± 2.82	—	19.3 ± 2.4
ASA (I/II/III)	Intervention	14/16	—	3/37/10	11/19/0	—
	Control	12/18	—	8/42/3	12/18/0	—
Previous VATS	Intervention	—	—	—	—	7 (21.2%)
	Control	—	—	—	—	11 (33.3%)
Total Anaesthesia Time (min)	Intervention	183.0 ± 37.0	174 ± 6	150 ± 45.8	161.38 ± 31.55	—
	Control	200.0 ± 43.1	168 ± 6	151.67 ± 49.53	165.83 ± 27.01	—
Total Surgery Time (min)	Intervention	131.3 ± 33.6	132 ± 6	120.03 ± 36.26	130.50 ± 28.07	—
	Control	146.0 ± 36.2	132 ± 6	126.67 ± 53.34	129.50 ± 23.94	—
Intraoperative Opioid Dose	Intervention	$561.7 \pm 145.4~\mu\mathrm{g}$	—	$33.9 \pm 9.31$	$161 \pm 36.15$	—
	Control	$583.3 \pm 124.1~\mu\mathrm{g}$	—	$45.43 \pm 9.07$	$171 \pm 50.87$	—
FEV$_1$ (% predicted)	Intervention	$82.2 \pm 16.5$	—	—	—	—
	Control	$85.1 \pm 14.4$	—	—	—	—
FEV$_1$/FVC (%)	Intervention	$95.13 \pm 41.72$	—	—	—	—
	Control	97.93 ± 47.64	—	—	—	—
Baseline HR (bpm)	Intervention	—	84.8 ± 2.3	—	—	—
	Control	—	82.3 ± 2.9	—	—	—
Baseline MAP (mmHg)	Intervention	—	95.5 ± 1.9	—	—	—
	Control	—	97.1 ± 1.5	—	—	—

BMI, Body Mass Index; ASA, American Society of Anesthesiologists Physical Status Classification; VATS, Video-Assisted Thoracoscopic Surgery; PVB, Paravertebral Block; TPVB, Thoracic Paravertebral Block; FEV₁, Forced Expiratory Volume in 1 second; FVC, Forced Vital Capacity; HR, Heart Rate; MAP, Mean Arterial Pressure; μg, Microgram; SD, Standard Deviation.

Table 2

Baseline characteristics of the included studies with sample size combination group/control

Study ID	Country	Study Design	Sample Size (Intervention/Control)	Surgical Procedure	Anesthesia Type
Jianghui Xu 2017	China	RCT	33/32	Video Assisted Thoracoscopic Surgery (VATS) lobectomy	General anesthesia plus ultrasound-guided multiple-level thoracic paravertebral block
Jun Zha 2021	China	RCT	20/20	Video-assisted Thoracoscopic lobectomy (VATS)	General anesthesia + thoracic paravertebral block
Zheping Chen 2024	China	RCT	30/30	Video-assisted Thoracoscopic surgery (VATS)	General anesthesia + thoracic paravertebral block
Rong Tang 2025	China	RCT	39/39	Video-assisted Thoracoscopic surgery (VATS)	General anesthesia + ultrasound-guided PVB (T5)
Boohwi Hong 2019	Korea	RCT	33/33	VATS wedge resection	General anesthesia with TPVB post-op

CT, Randomized Controlled Trial; VATS, Video-Assisted Thoracoscopic Surgery; PVB, Paravertebral Block; TPVB, Thoracic Paravertebral Block.

Anesthesia and surgery-related variables were also collected to ensure comparability. The total anesthesia time ranged between approximately 125 and 200 minutes across studies, with no substantial difference between the groups. Similarly, total surgery time showed only slight variations, ranging from about 90 to 146 minutes. The intraoperative opioid doses, primarily measured in fentanyl equivalents, were nearly identical across intervention and control arms. Pulmonary function, measured by FEV$_1$ and FEV$_1$/FVC ratios, showed similar values in both groups, indicating comparable respiratory baselines. Additionally, baseline hemodynamic parameters such as heart rate (HR) and mean arterial pressure (MAP) were closely matched, further supporting the internal validity of the pooled analysis.

All studies were rated as having a low risk in all five ROB2 domains, including missing outcome data, measurement of outcomes, and selection of the reported result. Only Jun Zha et al. (2021) and Jianghui Xu et al. (2017) raised concerns in one or more domains, primarily related to deviations from the intended intervention and the selection of reported results.

Outcome

Bradycardia

There was no statistically significant difference in the incidence of bradycardia between patients receiving dexmedetomidine added to ropivacaine (PRD group) and those receiving ropivacaine alone (PR group) in thoracic surgeries (RR = 2.14; 95% CI: 0.71–6.40; p = 0.1750). (Figure 2; A)

Dizziness

There is no statistically significant difference in the incidence of dizziness in patients receiving dexmedetomidine added to ropivacaine (PRD group) and those receiving ropivacaine alone (PR group). The pooled risk ratio (RR = 1.52; 95% CI: 0.71–3.27; p = 0.2833). Although the point estimate suggests a slightly higher risk of dizziness in the PRD group, the result is not statistically meaningful, and the confidence interval crosses 1. Therefore, no firm conclusion can be drawn regarding the effect of PRD on dizziness. (Figure 2; B)

Hypotension

There is no statistically significant difference in the risk of hypotension between patients receiving dexmedetomidine added to ropivacaine (PRD group) and those receiving ropivacaine alone (PR group). The pooled risk ratio (RR: 0.78, 95% CL: [0.40, 1.53], p = 0.4676), (Figure 2; C)

Nausea

There is no statistically significant difference in the incidence of nausea between patients receiving dexmedetomidine added to ropivacaine (PRD group) and those receiving ropivacaine alone (PR group). The pooled risk ratio (RR: 1.15; 95% CI: [0.65, 2.03]; p = 0.6018). (Figure 3; D)

Vomiting

There is no statistically significant difference in the incidence of vomiting between patients receiving dexmedetomidine added to ropivacaine (PRD group) and those receiving ropivacaine alone (PR group). The pooled risk ratio (RR: 1.04; 95% CI: [0.54, 2.02]; p = 0.9122). (Figure 3; E)

Discussion

In this systematic review and meta-analysis of randomized controlled trials, the addition of dexmedetomidine to ropivacaine in thoracic surgical settings was found to be safe, with no statistically significant increase in adverse events, including bradycardia, hypotension, dizziness, nausea, or vomiting.

Several of the included trials suggested that dexmedetomidine may enhance analgesia, prolong the duration of nerve blocks, and reduce opioid consumption. However, due to heterogeneity in study design, outcome definitions, and incomplete reporting, we were unable to perform a quantitative synthesis of these efficacy outcomes. Therefore, these potential benefits should be interpreted with caution. The current evidence base is insufficient to draw definitive conclusions regarding analgesic or opioid-sparing effects.

Our findings are consistent with previous reports that dexmedetomidine, when used as an adjuvant to local anesthetics, has the potential to improve block quality and prolong analgesia. We support the safety of dexmedetomidine as an adjuvant to ropivacaine in thoracic anesthesia. However, the efficacy claims suggested in individual studies require further verification through larger, well-designed randomized trials with standardized reporting of pain and opioid-related outcomes. Hong et al. demonstrated significantly lower cumulative opioid consumption over 24 h and better pain with coughing, with no patient requiring atropine despite lower heart rates. Similar improvements in analgesia, sedation scores, and hemodynamic stability were also observed in trials using thoracic trunk plane blocks (TTPB), with no increase in adverse reactions, except for potential drowsiness [¹⁰].

Our findings fit into a broader, somewhat mixed, evidence base. Multiple systematic reviews and meta-analyses have consistently demonstrated that dexmedetomidine as a perineural or neuraxial adjuvant prolongs sensory and motor block duration, delays first analgesic request, and reduces postoperative opioid consumption when combined with local anesthetics such as ropivacaine. For example, pooled data across RCTs show clinically meaningful prolongation of analgesia and block duration when dexmedetomidine is added to ropivacaine.

Bradycardia has been reported as the main safety concern in some earlier reviews of neuraxial and perineural dexmedetomidine. These studies advised caution, especially when higher doses are used or when the drug may be absorbed into the bloodstream. In neuraxial administration, one major meta-analysis found a higher rate of bradycardia and recommended close monitoring [¹¹,¹²]. The accumulated evidence supports that adding dexmedetomidine to ropivacaine reliably improves block quality and prolongs analgesia, which is attractive in thoracic surgery, where effective regional analgesia reduces opioid needs and pulmonary complications. At the same time, clinicians should recognize the potential for bradycardia; our pooled estimate suggests an increased risk, although it was not statistically significant.

Zhang et al. found no difference in dizziness incidence between dexmedetomidine–local anesthetic combinations and controls across various block types [¹³,¹⁴].In contrast, Sun et al. reported similarly non-significant results but noted a slight, clinically mild increase in sedation-related symptoms—particularly at perineural doses exceeding 100 µg [¹⁵]. In line with these reports, our pooled estimate aligns with this finding. Similarly, our findings for hypotension showed no significant difference between groups, which aligns with earlier systematic reviews in both thoracic and non-thoracic regional anesthesia settings. For instance, Liu et al. reported that the incidence of hypotension was comparable between the dexmedetomidine-local anesthetic groups and controls in peripheral nerve blocks, emphasizing that patient comorbidities and intraoperative management played a larger role in determining hemodynamic changes. In contrast, meta-analyses of neuraxial dexmedetomidine, such as the one by Sun et al., have observed a higher rate of hypotension, likely attributable to combined sympathetic blockade and systemic absorption [¹⁶]. Our results are more consistent with the peripheral and paravertebral block literature, in which hypotension has been an infrequent event and generally unrelated to the use of dexmedetomidine at moderate perineural doses. Taken together, these findings suggest that, within the dosing range and techniques applied in the included trials, dexmedetomidine does not appear to significantly increase the risk of hypotension in thoracic surgery patients.

In summary, this meta-analysis provides evidence that the addition of dexmedetomidine to ropivacaine for thoracic paravertebral block offers enhanced analgesic benefits without a corresponding increase in adverse events. This supports the thesis that dexmedetomidine is a safe and effective adjuvant in thoracic anesthesia.

However, our analysis was limited to safety and adverse outcomes as the included studies demonstrated considerable heterogeneity in dosing strategies and methods of outcome reporting. We recommend that more homogeneous trials are needed to better define optimal dosing, clarify the specific analgesic benefits, long-term safety outcomes, and the impact on a patient’s quality of life.

Conclusions

Across five small RCTs, pooled safety outcomes did not differ; efficacy effects remain uncertain due to inconsistent reporting that precluded quantitative synthesis. The addition of dexmedetomidine to ropivacaine in thoracic surgeries did not demonstrate any significant differences compared with ropivacaine alone across all evaluated adverse outcomes, including bradycardia, dizziness, hypotension, nausea, and vomiting. Although some outcomes showed a slight tendency toward higher incidence in the dexmedetomidine group, these trends were not consistent or conclusive. Overall, the findings suggest that dexmedetomidine can be used as an adjuvant without a clear increase in common adverse effects, but continued vigilance and further high-quality research are warranted to confirm its safety profile in this setting.