Antediluvian Methods? An Evidence-Based Approach to Wound Irrigation
Authors: Ryan Mason, MD and Alex St. John, MD (University of Washington, Division of Emergency Medicine)
Edited by: Alex Koyfman, MD (@EMHighAK) and Brit Long, MD (@long_brit, EM Chief Resident at SAUSHEC, USAF)
It is the middle of a busy shift in your small emergency department when a 26 year-old man presents with a laceration to his right forehead sustained 2 hours prior. He tripped at his worksite and struck his head on a shelf. He denies other trauma, loss of consciousness, or neurologic symptoms. He has no chronic medical conditions. The wound is linear, 3cm in length, and bone is not visible. A complete neurovascular exam is intact.
You determine the wound requires primary closure, but what is the role of irrigation?
Traditionally, laceration repair education has focused mainly on suturing and wound closure techniques. However, irrigation to reduce bacterial colony burden plays an equally important role in laceration repair by preventing infection.1 In this article, we explore the evidence and techniques surrounding wound irrigation including: Volume, Pressure, Type of Solution, and Primary Closure without Irrigation.
- Tap Water vs Normal Saline
Many institutions currently favor the use of sterile normal saline for wound irrigation. This practice is costly to already overstretched ED budgets. One study found irrigating patients with normal saline imposed 10-fold price increase over tap water ($0.91 versus $9.11).2 But, is making the switch to tap water right for our patients? Below is a summary of recent literature surrounding Normal Saline and Tap Water use in ED wound irrigation:
- Moscati, et al 20073: Compared infection rates in lacerations irrigated with Sterile Saline vs Tap Water
- Multi-center, prospective randomized trial
- 634 patients enrolled and followed up
- Infection rate: Tap Water group 12/300 (0%), Sterile Saline group 11/334 (3.3%)
- 2012 Cochrane Review4:
- Six trials
- Included both children and adults
- “Evidence suggests that tap water is unlikely to be harmful if used for wound cleansing.”
- Weiss, et al, 20135: Compared infection rates in lacerations irrigated with Sterile Saline vs Tap Water
- Single-center, prospective, randomized trial
- 625 subjects enrolled
- Infection rate: Tap Water group 5% (CI +/-2.0%); Sterile Saline group 6.4% (CI +/-2.7%)
Caveats & Bottom Line
- Know the studied populations – nearly every article excluded:
- grossly contaminated wounds
- puncture wounds
- wounds older than 8 hours
- wounds exposing deep structures
- immunocompromised patients, including diabetics
There is compelling evidence that tap water is equal in efficacy for wound irrigation in the ED. In routine irrigation of wounds in the ED, reach for the tap instead of a bottle of NS. In the unstudied populations listed above, normal saline is still the best choice for now.
- Irrigation Pressure
Pressure is an important component in irrigation. Too little pressure will not effectively reduce the bacterial burden.6 Literature is limited regarding the effectiveness of different pressures. Dogma and a small number of animal studies from the 1970s and 1980s suggest 7-8 psi as a minimum pressure to achieve effective irrigation.6–7 Until further studies are done, this is the best evidence we have. How do you know how much pressure you are generating? Luckily, this has been studied.
Singer, et al. 19948: Four different irrigation methods measured by pressure transducer
- 10 volunteers performing each method once
- Irrigation methods:
- 35ml & 65ml syringe with 19-gauge needle
- IV bag pierced with 19-gauge needle
- Plastic saline bottle pierced with 19-gauge needle
- Saline bottle and IV bag failed to produce adequate pressures at 2 and 6 psi, respectively
- 19-gauge needle methods produced adequate pressures of 16-43 psi
Caveats & Bottom Line
- Pierced IV bags and bottles do NOT provide enough pressure for wound irrigation
- Use a 19-, or similar, gauge needle to provide adequate pressure for wound cleansing
- Don’t forget, the American Society of Mechanical Engineers regulates water faucets to provide 20-80 psi. One study found a “standard laboratory faucet” to be about 45 psi.2 (And we just talked about the efficacy of tap water!) If anatomically appropriate, instruct the patient to run their wound under a faucet.
- Irrigation Volume
During training, most physicians are exposed to the dogma regarding irrigation that, “the solution to pollution is dilution.” Both Rosen’s and Tintinalli’s recommend “copious irrigation” of wounds. Yet, both sources remain vague regarding the ideal amount. Tintinalli’s recommends 60cc per cm of wound length. More irrigation to reduce contamination seems intuitive. Perhaps because of this, review of the literature does not reveal any direct investigation of irrigation volume. Anecdotally, most studies reviewed for this article cite irrigation times between 2 and 4 minutes.
Caveats & Bottom Line
- In lieu of any strong evidence, texts recommend 60cc of irrigant per cm of wound length
- Need for Irrigation in “Clean” Wounds?
The benefits of irrigation in contaminated wounds have been documented,6 but what about relatively “clean” wounds? In particular, the high vascularity of the face and scalp is thought to be protective against wound infection.9 This 1997 study investigated the benefits of irrigation in these highly-vascularized “clean” wounds:
Hollander, et al. 199710: Compared wound infection and cosmesis in head & scalp lacerations closed with and without irrigation
- >1900 patients, enrolled in prospective, blinded trial in academic ED
- Outcomes: Rates of wound infection and blinded cosmetic outcomes
- Non-randomized: physicians’ discretion decided irrigation/no irrigation group placement
- Excluded: Immunocompromised, diabetics, renal failure, and wounds with fascial involvement
- Follow-up loss rate was unclear
- No significant difference between irrigation vs no irrigation groups for both cosmesis and infection
Caveats & Bottom Line
- Exclusion criteria limits generalization
- Unclear effects of bias given non-randomization or known loss to follow up
- Interesting, but more studies are needed before adoption of irrigation-free wound closure can be recommended
- Tap water is equally efficacious as saline for routine wound irrigation in uncomplicated wounds and immunocompetent patients.
- Ideal irrigation pressure can be achieved using a 19-gauge or similar needle or a tap faucet; avoid IV bags and bottles.
- Very little data exist regarding ideal volumes of irrigation – texts recommend 60 cc/cm.
- Data is promising, but not yet convincing, that clean scalp and facial wounds may be closed safely without irrigation.
References / Further Reading
- Hollander JE, Singer AJ. STATE OF THE ART L aceration Management. 1999;(September).
- Moscati RM, Reardon RF, Lerner EB, Mayrose J. Wound irrigation with tap water. Acad Emerg Med. 1998;5(11):1076-1080.
- Moscati RM, Mayrose J, Reardon RF, Janicke DM, Jehle D V. A Multicenter Comparison of Tap Water versus Sterile Saline for Wound Irrigation. Acad Emerg Med. 2007;14(5):404-409. doi:10.1197/j.aem.2007.01.007.
- Fernandez R, Griffiths R. H2O for wound cleansing (review). Cochrane Libr. 2012;(2):1-30.
- Weiss EA, Oldham G, Lin M, Foster T, Quinn JV. Water is a safe and effective alternative to sterile normal saline for wound irrigation prior to suturing: a prospective, double-blind, randomised, controlled clinical trial. BMJ Open. 2013;3(1):1-6. doi:10.1136/bmjopen-2012-001504.
- Rodeheaver G, Petty D, Thacker J. Wound cleansing by high pressure irrigation. Surgery, Gynecol Obstet. 1976;141:357-362.
- Hamer ML, Robson MC, Krizek TJ, Southwick WO. Quantitative bacterial analysis of comparative wound irrigations. Ann Surg. 1975;181(6):819-822. doi:10.1097/00000658-197506000-00010.
- Singer a J, Hollander JE, Subramanian S, Malhotra a K, Villez P a. Pressure dynamics of various irrigation techniques commonly used in the emergency department. Ann Emerg Med. 1994;24(1):36-40. doi:10.1016/S0196-0644(94)70159-8.
- Singer a J, Hollander JE, Cassara G, Valentine SM, Thode HC, Henry MC. Level of training, wound care practices, and infection rates. Am J Emerg Med. 1995;13(3):265-268. doi:10.1016/0735-6757(95)90197-3.
- Hollander JE, Richman PB, Werblud M, Miller T, Huggler J, Singer a. J. Irrigation in facial and scalp lacerations: Does it alter outcome? Ann Emerg Med. 1998;31(1):73-77. doi:10.1016/S0196-0644(98)70284-7.