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Three Part Question

In [adult patients with no underlying vascular compromise undergoing digital block] is [local anaesthetic with low dose epinephrine as safe as local anesthetic alone] at [achieving analgesia without causing ischaemic complications]?

Clinical Scenario

A 25-year-old man presents to the emergency department with a traumatic laceration to his left index finger. The wound needs a thorough clean and will require suturing and you decide to do this using a digital nerve block technique. A colleague who has recently worked in plastic surgery suggests you use epinephrine (1:100 000) to help with haemostasis, but you have always been told that this can cause finger necrosis and that it should never be done. You wonder whether in fact this is true and decide to look at the evidence for yourself.

Search Strategy

Medline search using Pubmed
("Anesthesia"[MeSH] OR "Anesthesia, Local"[MeSH]) OR "Nerve Block"[MeSH] AND "Epinephrine"[MeSH] AND "Fingers"[MeSH]

Search Outcome

16 papers retrieved of which 7 were found to be relevant. There were 2 randomised control trials, 3 observational cohort studies and 2 review articles.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Andrades et al. April 2003 USA	Study group (n = 21) received 2% lignocaine with 1:100 000 epinephrine and control group (n = 22) received 2% lignocaine	Randomised control trial	Pain score at 1 hour	Study group = 1.4, control group = 4.1 (p<0.05)	Small study
			Need for further anaesthetic dose	Study group = 4%, control group = 24% (p<0.05)
			Duration of analgesia	Study group = 4.6 h, control group = 2.4 h (p<0.05)
			Ischaemic damage	None
Krunic et al. 2004 November USA	Review of all reported cases of digital gangrene associated with the use of epinephrine from National Library of Medicine	Review article	Presence of confounding factors in the reported cases	21 reported cases of digital gangrene involved the use of epinephrine. Factors such as inappropriate mixing of epinephrine, use of older agents, inappropriate use of tourniquet, use of hot soaks, infection, and large volume of injection were associated with the reported cases. No case reported epinephrine as the sole cause of gangrene	Historical Review
Wilhelmi et al. 1998 October USA	23 procedures with digital ring bock using lignocaine 1% with adrenaline 1:100,000 (n=11) or 1:200,000 (n=12).	Observational cohort study	Ischaemic damage	None	Small case series, use of two different strengths of epinephrine
Sylaidis et al. 1998 February UK	100 consecutive patients underwent digital ring block using lignocaine 2% with adrenaline 1:80,000.	Observational Cohort Study	Digital–brachial pressure index (ratio of digital to brachial artery systolic blood pressures)	Mean fall of 19% in digital–brachial pressure index following the block (SD 14.6%).	The digital blood pressures were not measured at the end of procedure
			Finger tip temperature	Mean increase of 0.8 (SD 2.3)°C following block
			Digital artery blood flow (10 patients, duplex scanner)	Blood flow returned to normal by 1 h in all cases
			Ischaemic damage	None
Altinyazar et al. 2004 April Turkey	24 adults undergoing blocks in fingers or toes with 2% lignocaine and 1:100 000 epinephrine	Observational cohort study	Digital artery blood flow at 10 min	Fall in peak systolic velocity by 60% and end diastolic velocity by 90%
			Digital artery blood flow at 60 min (n=21)	Blood flow returned to pre-block measurement
			Digital artery blood flow at 90 min (n=3)	Blood flow returned to pre-block measurement
Denkler 2001 July USA	Review of all reported cases of ischaemic digital necrosis associated with the use of epinephrine from 1880 to 2000	Review article	Presence of confounding factors in reported cases of ischaemic damage	21 out of 48 reported cases of digital gangrene involved the use of epinephrine. Confounding factors such as inappropriate concentration of epinephrine, use of older local anaesthetics, excessive volume of injection, prolonged use of tourniquet, use of hot soaks and infection were identified with all reported cases of gangrene
Wilhelmi et al. 2001 February USA	Study group (n = 31) had digital block using 1% lignocaine with 1:200 000 epinephrine. Control group (n = 29) had 1% lignocaine plain	Randomised control trial	Need for tourniquet	Study group = 9/31, control group = 20/29, (p<0.002)
			Need for further anaesthetic dose	Study group = 1/31, control group = 5/29 (p = 0.098)
			Ischaemic complications	None

Comment(s)

Two review articles carefully examined the previously reported cases and found that no case had epinephrine as the sole cause of ischaemic complication. Two studies examined the digital perfusion using Doppler flow, and concluded that the blood flow returned to normal by 1 h after epinephrine injection. Other randomised and observational studies showed longer duration of anaesthesia, better analgesia, less need for tourniquets and no ischaemic damage with the use of epinephrine. This is clearly a controversial topic as it has been emergency medicine dogma that vasoconstrictive agents should not be used in digits. However, the evidence does not support this assertion for all patients. Clinicians may decide to use low concentration epinephrine when they feel this may help the procedure and where there is no underlying reason not to do so.

Clinical Bottom Line

In the absence of underlying vascular compromise, epinephrine (1:200 000 to 1:100 000) is safe to use in digital blocks along with local anaesthetics.

References

1. Andrades PR, Olguin FA, Calderon W. Digital blocks with or without epinephrine. Plastic and Reconstructive Surgery 2003 Apr 15;111(5):1769-70.
2. Krunic AL, Wang LC, Soltani K, Weitzul S, Taylor RS. Digital anesthesia with epinephrine: an old myth revisited. Journal of American Academy of Dermatology 2004 Nov;51(5):755-9.
3. Wilhelmi BJ, Blackwell SJ, Miller J, Mancoll JS, Phillips LG. Epinephrine in digital blocks: revisited. Annals of Plastic Surgery 1998 Oct;41(4):410-4
4. Sylaidis P, Logan A. Digital blocks with adrenaline. An old dogma refuted. Journal of Hand Surgery (British) 1998 Feb;23(1):17-9.
5. Altinyazar HC, Ozdemir H, Koca R, Hosnuter M, Demirel CB, Gundogdu S. Epinephrine in digital block: color Doppler flow imaging. Dermatologic Surgery 2004 Apr;30(4 Pt 1):508-11.
6. Denkler K. A comprehensive review of epinephrine in the finger: to do or not to do. Plastic and Reconstructive Surgery 2001 Jul;108(1):114-24
7. Wilhelmi BJ, Blackwell SJ, Miller JH, Mancoll JS, Dardano T, Tran A, Do not use epinephrine in digital blocks: myth or truth? Plastic and Reconstructive Surgery 2001 Feb;107(2):393-7