Introduction Venous sampling for blood gas analysis has been suggested as an alternative to arterial sampling in order to reduce pain. The main objective was to compare pain induced by venous and arterial sampling and to assess whether the type of sampling would affect clinical management or not.
Methods We performed an open-label randomised multicentre prospective study in four French EDs during a 4-week period. Non-hypoxaemic adults, whose medical management required blood gas analysis, were randomly allocated using a computer-generated randomisation list stratified by centres with an allocation ratio of 1:1 using random blocks to one of the two arms: venous or arterial sampling. The primary outcome was the maximal pain during sampling, using the visual analogue scale. Secondary outcomes pertained to ease of sampling as rated by the nurse drawing the blood, and physician satisfaction regarding usefulness of biochemical data.
Results 113 patients were included: 55 in the arterial and 58 in the venous sampling group. The mean maximal pain was 40.5 mm±24.9 mm and 22.6 mm±20.2 mm in the arterial group and the venous group, respectively, accounting for a mean difference of 17.9 mm (95% CI 9.6 to 26.3) (p<0.0001). Ease of blood sampling was greater in the venous group as compared with the arterial group (p=0.02). The usefulness of the results, evaluated by the prescriber, did not significantly differ (p=0.25).
Conclusions Venous blood gas is less painful for patients than ABG in non-hypoxaemic patients. Venous blood gas should replace ABG in this setting.
Trial registration number NCT03784664.
- analgesia/pain control
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Handling editor Edward Carlton
Contributors TA, NB, JB, ACh, LD, DD, NK, CO, YS, MW, SG, JL, ACo and DR conceived the study and designed the trial. DR, ACh and JL supervised the conduct of the trial and data collection. TA, NB, JB, ACh, LD, DD, NK, CO, YS, MW, SG and DR undertook recruitment of participating centres. ACh, NJ, AG, SC, AA, PP and EC undertook recruitment of patients and managed the data, including quality control. JL provided statistical advice on study design and analysed the data. ACh and DR drafted the manuscript, and all authors contributed substantially to its revision. All authors approved the final manuscript. DR takes responsibility for the paper as a whole.
Funding This study has been designed and conducted in the context of an optional learning course ('Initiation to clinical research') from Paris Diderot Medical School, Université de Paris, Paris. Collection, analysis and interpretation of data were done under the supervision of an associate professor of the Biostatistics Department of Saint Louis Hospital, Assistance Publique—Hôpitaux de Paris, Paris, France (JL), who participated to the learning course. Overall, Université de Paris and Assistance Publique—Hôpitaux de Paris financially supported the research.
Disclaimer The sponsors had no other role regarding the trial.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Authorisation by the institutional review board (Comité de Protection des Personnes) of the ethics committee Ile de France IV (IRB 00003835) was obtained (registered 24 December 2018; https://clinicaltrials.gov/ct2/show/NCT03784664). Patients received verbal and written information about the study by an investigator. In absence of opposition to participate, inclusion of the patient was notified in the medical file followed by randomisation.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. Deidentified participant data are available on reasonable request (Anthony.firstname.lastname@example.org).
Author note Ten medical students developed the protocol under supervision during the university learning course “initiation to clinical research”. Student authorship, identified in the title page, is in alphabetical order.
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