Coughing can reduce pain of injection, study showsBMJ 2004; 328 doi: http://dx.doi.org/10.1136/bmj.328.7437.424-c (Published 19 February 2004) Cite this as: BMJ 2004;328:424
So, how can patients be distracted from the pain of an injection? Many tactics have been tried,including cartoons, hypnosis, music, jokes, and counter-pressure, but doctors now report high success rates with a simple cost-free, and risk-free strategy, that requires no specialist equipment—coughing.
As the needle comes into contact with the skin, the patient is urged to cough vigorously. That cough, say the doctors, in an article published online ahead of print in the British Journal ofPlastic Surgery (www.bjps.com), may provide distraction and momentarily increase blood pressure. The authors say that it has been established that hypertension can reduce pain perception.
They point out that percutaneous insertion of needles, including the passage of intravenous cannulae or the injection of local anaesthetic agents, can be an extremely uncomfortable experience for patients.
“A number of methods, both pharmacological and non-pharmacological, have been described in the literature to help alleviate this discomfort. Of these, distraction appears to be the single most effective technique, with numerous reports of its efficacy in reduction of the pain of injections and dressing changes,” say the authors, from St Thomas's Hospital, London, Norfolk and Norwich University, and Wycombe General Hospital.
They say that although there is little doubt that distraction works, the exact mechanism has not been established. It may, they suggest, be explained by the gate control theory of pain, and that stimuli travelling along fast nerve fibres partially override painful sensations travelling along slower nerve fibres.
The authors also say that coughing may work both as a distracter and as a trigger for a sudden rise in blood pressure: “It is already known that hypertension can cause reduced pain perception and, in addition to its ability to distract patients momentarily from the painful task at hand, coughing may also act by causing a sudden rise in blood pressure,” they say.
They add that the cough strategy is easy and effective: “We use a simple method of distraction,which has proved to be highly effective in both adults and older children, and does not require any specialized equipment. At the time of injection, the patient is asked to give a strong cough. For maximal effect, it is important for the cough to coincide with the insertion of the needle. If the patient requires several injections, the cough is repeated for each.”
The authors say that most of their patients reported reduced pain perception with the technique, including those given local anaesthetic injections.
They say that the technique merits further study and add, “It is certainly risk-free and easy to perform, and we would recommend its use by all clinicians at the time of insertion of intravenous cannulae and infiltration of local anaesthetic solutions.”
These findings add weight to the results of another recent study that showed that coughing relieves pain when blood is being taken (Anesthesia and Analgesia 2004;98:343-5).