Local anaesthetic infiltration reduces the pain of arterial blood sampling
Date First Published:
October 2, 2000
Last Updated:
September 20, 2001
Report by:
Damian Bates, Specialist Registrar (Oldham Royal Hospital)
Search checked by:
Peter Cutting, Oldham Royal Hospital
Three-Part Question:
In [a patient requiring blood gases or arterial puncture] does [an injection of local anaesthetic][reduce pain without affecting success]?
Clinical Scenario:
A 67 year old man attends with increasing shortness of breath. He is known to have obstructive airways disease. You want to perform arterial puncture for blood gases. He tells you that last time it was very painful.You wonder if an injection of local anaesthetic would help?
Search Strategy:
Medline 1966-07/2001 using the Ovid interface.
Search Details:
[{exp blood gas analysis OR abg.mp OR arterial blood gas$.mp OR blood gas$.mp} OR ({exp arteries OR artery.mp OR arterial.mp AND {exp punctures OR puncture$.mp OR exp catheterisation OR cannulation.mp OR cannula.mp}) AND {exp anesthesia, local OR anesthetics, local OR local anesthesi$.mp OR local anaesthesi$.mp} AND {exp pain OR pain$.mp}] LIMIT to human AND english
Outcome:
88 papers were identified of which 3 were relevant.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Arterial versus capillary sampling for analysing blood gas pressures. Dar K, Williams T, Aitken R, et al. 1995, England | 55 acute medical admissions requiring blood gas measurement. Capillary samples from all patients, plus arterial sample after infiltration of 1% lignocaine or no infiltration using 22G needle |
PCT | Pain of arterial puncture using a scale 0 to 10. | Lower mean pain score with LA 2.0 vs 7.0 without LA | Did not assess significance of difference between LA or not. Pain scores for capillary sampling are different for the two groups |
| Preference of capillary or arterial sampling | Capillary sampling less painful | ||||
| Comparability of results from arterial and capillary samples | Mean differences for pO2 and pCO2 were not significant. Mean differences for pH and standard bicarbonate reported to be significant but clinically unimportant | ||||
| Pain during arterial puncture Giner J, Casan P, Belda J, et al. 1996, Spain | 270 pts attending pulmonary function lab for abg. Arterial puncture with 22g needle after infiltration with 1% mepivacaine, placebo or nothing |
PRCT | Pain using 10 cm visual analogue scale | Less pain with LA (1.5 cm vs 3.06 cm with placebo, p=0.00001) (1.5 vs 2.8 cm with nothing, p=0.0002) | Not emergency patients |
| Time to prepare and perform | Less time without LA (134 seconds vs 171 seconds with infiltration, p<0.05) | ||||
| Success at first pass | First pass success 93% with LA, 91% with placebo and 90 % without infiltration, significance not tested. | ||||
| Local anaesthetic infiltration prior to arterial puncture for blood gas analysis: a survey of current practice and a randomised double blind placebo controlled trial. Lightowler JV, Elliott MW. 1997, England | 101 pts requiring abg. Arterial puncture with 29G needle after infiltration with 2% lignocaine, placebo or nothing. |
PRCT | Pain, using a 4 point scale | Arterial puncture less painful with LA (1.5 vs 2.2 with placebo p=0.0008, 1.5 vs 2.1 with nothing p=0.0005) | Separates pain of infiltration from arterial puncture in scoring |
| Difficulty of procedure as number of times skin broken, number of passes made and doctor rating. | No difference in difficulty, doctor rating 1.2 with LA vs 1.1 placebo vs 1.1 nothing |
Author Commentary:
Lightowler and Elliott surveyed junior doctors prior to their study and found that 84% never used local anaesthetic prior to arterial puncture citing that it made the procedure both more difficult and more painful. Dar et al cite two papers which showed delay in presentation to be an important contributor to deaths from asthma and suggest that a previous painful experience could lead to such a delay.
Bottom Line:
Local anaesthetic infiltration prior to arterial puncture significantly reduces the pain of the procedure without affecting success rates.
References:
- Dar K, Williams T, Aitken R, et al.. Arterial versus capillary sampling for analysing blood gas pressures.
- Giner J, Casan P, Belda J, et al.. Pain during arterial puncture
- Lightowler JV, Elliott MW.. Local anaesthetic infiltration prior to arterial puncture for blood gas analysis: a survey of current practice and a randomised double blind placebo controlled trial.