To determine whether local warming of the
lower arm and hand facilitates peripheral venous cannulation.
Single blinded prospective randomised
controlled trial and single blinded randomised crossover trial.
Neurosurgical unit and haematology ward of
100 neurosurgical patients and 40
patients with leukaemia who required chemotherapy.
Neurosurgical patients' hands and
forearms were covered for 15 minutes with a carbon fibre heating mitt.
Patients were assigned randomly to active warming at 52°C or passive
insulation (heater not activated). The same warming system was used for
10 minutes in patients with leukaemia. They were assigned randomly to
active warming or passive insulation on day 1 and given alternative
treatment during the subsequent visit.
Main outcome measures
Primary: success rate for
insertion of 18 gauge cannula into vein on back of hand. Secondary:
time required for successful cannulation.
In neurosurgical patients, it took 36
seconds (95% confidence interval 31 to 40 seconds) to insert a cannula
in the active warming group and 62 (50 to 74) seconds in the passive
insulation group (P=0.002). Three (6%) first attempts failed in the
active warming group compared with 14 (28%) in the passive insulation
group (P=0.008). The crossover study in patients with leukaemia
showed that insertion time was reduced by 20 seconds (8 to 32,
P=0.013) with active warming and that failure rates at first attempt
were 6% with warming and 30% with passive insulation (P<0.001).
Local warming facilitates the insertion
of peripheral venous cannulas, reducing both time and number of
attempts required. This may decrease the time staff spend inserting
cannulas, reduce supply costs, and improve patient satisfaction.
What is already known on this topicInsertion of peripheral venous cannulas may be difficult because of
severe vasoconstrictionVasoconstriction can be overcome by local heatingWhat this study addsActive local warming facilitates the insertion of peripheral venous
cannulas, reducing both the time and number of attempts
requiredLocal warming will decrease the amount of time staff spend inserting
cannulas, reduce supply costs, and improve patient