The combinatorial therapy consisting of ropivacaine with dexmedetomidine generates a superior brachial plexus blocking effect than ropivacaine monotherapy, both intraoperatively and postoperatively.

A rise in the number of automated vehicles increases the incidence of various types of traffic traumas. Upper limb fracture is one of them. Management of severe pain in upper limb fractures is achieved with analgesia by brachial plexus blockade. It is usually applied before surgery. However, patients remain anxious and nervous before and during operation, leading to heart rate (HR) decrease, blood pressure increase and even shock.

Administration of appropriate analgesics is integral. Traditional analgesics such as fentanyl were more prone to over anaesthesia, increased perioperative risks and are not conducive to postoperative recovery. Brachial plexus regional anaesthesia is the preferred treatment option for upper limb fracture surgery because it is easy to execute and can be done in the waking state during operation. At present, the technique of brachial plexus blockade is performed under the guidance of ultrasonography, where local anaesthetics are continuously injected into the location to be blocked via a connection tube installed by visualisation technique. The technique is easy to use and helps in dose adjustment of anaesthetic according to operative time and analgesic requirement of patients.

To achieve a stronger anaesthetic effect, the route and choice of anaesthetics are essential. An ideal sedative is the one that can produce a robust anaesthetic effect without the incidence of adverse effects. Ropivacaine is one such local anaesthetic that inhibits neuronal excitement and conduction by blocking neuronal sodium channels. It generates a stronger anaesthetic effect by producing nerve inhibitory effect at low concentrations. The effects are long lasting with a weak central nerve inhibitory activity, making it a commonly used anaesthetic in nerve block anaesthesia. It also generates a vasoconstrictive effect resulting in reduced drug absorption in plasma and a long-lasting effect. It is also used in ideal anaesthetics in relieving a variety of postoperative pain. Dexmedetomidine, a highly selective α2 adrenergic receptor agonist, shows a higher affinity for its receptor and 7-8 times more effective than clonidine, that belongs to the same class. It also shows a faster onset of action and long lasting effect. It can also be used as an analgesic, sedative and anxiolytic agent. Previous studies have revealed the neuroprotective effects of dexmedetomidine by an increase in calcium levels and the reduction in the concentration of catecholamines. Thus, it can also be used as an adjuvant in anaesthesia.

Rationale behind research:

Several studies have determined the dose and efficacy of the combination of two anaesthetics in different race cohorts, but a few studies have elucidated the efficacy of the ropivacaine-dexmedetomidine combination. Therefore, the present study investigated the analgesic effect of ropivacaine-dexmedetomidine in brachial plexus block and compared its effect with that of ropivacaine alone.

Objective:

The study was intended to evaluate the efficacy and safety of ropivacaine in combination with dexmedetomidine versus ropivacaine alone in 114 patients with upper limb surgery. 

Study outcomes:

• Patient demographic characteristics were evaluated at baseline
• The primary outcome includes evaluation of changes in postoperative VAS scores versus baseline
• The secondary outcomes included determination of time to onset of the blockade, time to recover sensation & movement, the total analgesic maintenance time, changes in HR, MAP and SPO2 and safety

Time Points: 0, 4, 8, 12 and 24 h

Outcomes:

Baseline: There were no significant differences observed at baseline

Study outcomes:

• There was a reduction remarked in the time of onset of sensory and motor nerve blockade whereas an increase in the duration of the blockade in the combination group as compared with the control group {Fig 2. & 3.}

• There were no statistically significant differences in the VAS scores between the two groups immediately and four h after surgery, but there was a reduction in the VAS scores observed in the combination group, at 8, 12 and 24 h after surgery {Fig 4.}

• No statistically significant differences were found in HR, MAP and SPO2 between the two groups before anesthesia, but after anesthesia, there was a reduction in HR and MAP, and an increase in the SPO2 in the combination group than the control group

• There was a reduction in the incidence of adverse effects in the combination group than the control group

The study indicated that the combination of ropivacaine with dexmedetomidine was effective in reducing VAS scores 8 to 24 h postoperatively when compared with ropivacaine alone in the management of upper limb surgery. Combination regimen was more effective in alleviating postoperative pain than ropivacaine alone. The improvement in pain reduction was observed due to longer blocking effects by the combination therapy on sensory and motor nerves.  The study also established that ropivacaine also with dexmedetomidine offers higher efficacy and safety than ropivacaine alone.

Combination of two kinds of anaesthetics can yield a synergistic effect leading to a reduction in the dose of both the drugs. Combination regimen induces a faster blockade onset, longer nerve blocking effect and lower VAS scores with significant improvement in vital signs such as HR, blood pressure and SPO2, and can reduce the incidence of adverse reactions. The results were consistent and superior in various aspects such as larger sample size, broader parameters (VAS score for assessing the anaesthetic effect) and a detailed description of adverse effects. The significant adverse effects reported were lethargy and nausea. The cases of adverse effects were few and more studies are required to verify the incidence of adverse effects.