Vapocoolants: A pain treatment during intravenous cannulation
Intravenous cannulation is a painful process that can provoke anxiety and stress. To overcome this, local anaesthesia was injected which can provide analgesia but its a painful procedure. Topical anaesthetic creams produces effect after 30-90 minutes. For quicker analgesic effects, vapocoolants have been used nowadays. It has been reported that use of vapocoolants allow more timely investigation and treatment with their quicker analgesic action, but studies have shown mixed results.
Blinded and unblinded randomized controlled trials were accomplished. Vapocoolants were compared with placebo or control to reduce the pain during intravenous cannulation in adults and children. Data were taken or registered from various data base sources and research papers with scanned reference list.
For primary outcomes of pain during cannulation, data were extracted by 3 review authors independently including the risk of bias. Further for the secondary outcomes of pain associated with the application of vapocoolant, first attempt success rate of intravenous cannulation were recorded. Random effect model were used in RevMan 5.3 and statistics were calculated.
Nine suitable studies were analyzed qualitatively, which includes the 1070 participants out of which 8 studies of 848 participants were selected for the assesment of pain during the intravenous cannulation. Reduction in pain were seen after the use of vapocoolants measured by linear 100mm visual analogue scale. One study was not included because of no effects of the intervention. After the analysis, results indicated that there was increase in the pain scores at the time of application. 8 minor adeverse events were reported in 279 vapocoolant participants. Exclusion of studies at high or unclear risk of bias did not materially alter the results after the sensitivity analysis.
According to the evidence of moderate quality, it was indicated that use of vapocoolant immediately before intravenous cannulation reduces the pain during the procedure. However, during the cannulation vapocoolant does not increases the difficulty of insertion of cannulation nor caused any serious adverse effects but mild discomfort during the application were noticed.