Our results demonstrate that forearm IVRA is as effective in providing a surgical block as compared to a conventional upper arm IVRA, even with a reduced, non-toxic dosage of local anesthetic. No severe complications were associated with the use of a forearm IVRA. Other benefits of the modified technique include a faster onset of sensory block, better tourniquet tolerance and a dryer surgical field. 

Intravenous regional anaesthesia (IVRA) is a simple and effective anaesthetic technique for hand and forearm surgery. This method is also named as Bier Block as Dr August Bier invented it in 1908, It provides complete anaesthesia during the operation. Systemic toxicity is the major complication after IVRA include convulsions, coma, respiratory depression and arrest and cardiovascular depression with possibly fatal consequences. Therefore, some physicians favour other locoregional techniques or even general anaesthesia for hand and forearm surgery.

In 1978, forearm tourniquet has been introduced by Rousso et al. It lower the dosage requirement of local aneasthetic and produce a good quality of analgesia. It has been proposed that sensory onset time is shorter after forearm IVRA than after upper arm IVRA. Finally, it has also been advised that a forearm tourniquet evokes less ischemic pain and therefore patient can be tolerate the pain for longer time with less need for additional analgesia or sedation. Despite these advantages, this method is  not widely used because it was believed that the interosseous vessels in the forearm might not be blocked during the procedure with a potential risk of incomplete hemostasis and leakage of local anesthetic into the circulation. Nevertheless, several studies have opposed that idea and have revealed that forearm IVRA is safe and effective.

Rationale behind research:

In clinical practice, the optimal anaesthesia technique for surgery of the distal extremity is still undecided.

Therefore, the current review was performed to synthesize the best evidence for this topic.

Objective:

To perform a systematic review and meta-analysis of the existing evidence related to the analgesic efficacy with the use of conventional, upper arm intravenous regional anesthesia (IVRA) as compared to a modified, forearm IVRA in adult patients undergoing procedures on the distal upper extremity. 

Study outcomes:

• Two authors (VD and YH) initially screened article titles independently. Abstracts of potentially relevant articles were subsequently assessed, and those without relevance were eliminated. Full-text manuscripts of all remaining studies were obtained, read and assessed qualitatively.
• Success rate of IVRA
• onset time of sensory block
• Tourniquet tolerance time and incidence of tourniquet pain necessitating additional sedative
• complications associated with forearm IVRA
• Choice of local anesthetic and dosage of local anesthetic were noted

Time period: NA

Outcomes:

• Risk of bias: There was lower risk of bias in two studies. Regarding the nature of the interventions, blinding of participants was not possible. However, in all the 3 studies, outcome-assessors were blinded to treatment allocation.
• Block success rate: After pooling of the results (I2= 0%; no heterogeneity), we could not find a difference in efficacy between the two techniques with a calculated RR of 0.98 [0.93, 1.05]
• Onset time of sensory block: Only Singh et al. investigated the onset time of sensory block and reported no difference between the two groups
• Tourniquet tolerance time and incidence of tourniquet pain necessitating additional sedatives: Tourniquet tolerance was described in 2 of 3 articles. Both the Singh et al. and Chiao et al. concluded that tourniquet tolerance time was longer with a forearm tourniquet. More specifically, mean VAS score rise to 3 after 10 min and above 4 after 40 min in the upper arm group versus a mean VAS of 0.5 after 10 min and less than 1.5 after 40 min
• Complications associated with forearm IVRA: From a total of 383 patients receiving forearm IVRA, only 1 patient (0.26%) reported numbness.

In conclusion, The current systematic review revealed that forearm IVRA is as effective than conventional upper arm IVRA in providing a surgical block. Forearm IVRA showed no severe complications. The forearm IVRA have following advantages over conventional method: Reduced the dose of local anesthetic, a faster onset of sensory block, better tourniquet tolerance and a dryer surgical field.