Adrenaline auto-injector injuries: Practical considerations in emergency management in a tertiary hand surgery unit

Abstract

Adrenaline auto-injectors are the first line treatment for anaphylaxis in the community setting. Both anaphylaxis and auto-injector carriage are increasing in prevalence. Adrenaline auto-injector injuries are common and most often involve the hand or digits. Such injuries carry a risk of ischemic necrosis due to profound vasoconstriction, especially if there is undying vascular pathology such as Raynaud’s disease. The effects can be readily reversed with local infiltration of phentolamine. A survey was circulated to 40 clinicians working in the emergency and hand surgery departments of a major urban center. Knowledge of adrenaline duration of action and its reversal (agent, dose and location in the hospital) was assessed. All clinicians working within the two departments were eligible for participation. Only 25% of clinicians surveyed were aware of the duration of action of adrenaline. Half were aware of the correct reversal agent and only 20% knew the correct dose. Only one person was aware of phentolamine’s location within the hospital. There is relatively poor clinician knowledge surrounding adrenaline reversal and a lack of easily accessible information available about dosing and drug location within the hospital. Given the time dependent nature of adrenaline auto-injector injuries Emergency Departments should consider stocking phentolamine in an emergency drugs fridge within the department along with a dosing guide. This is likely to greatly reduce time from presentation to treatment and thus the chances of digital ischemia progressing to necrosis.

1. Introduction

Anaphylaxis is a serious allergic reaction of acute onset that may cause death.^[1] It has a prevalence of 50 to 103 episodes per 100,000 individuals per year.^[2] First line treatment for anaphylaxis in the community setting is adrenaline (epinephrine) administered via a portable auto-injector.^[3,4] Continual improvements in design have meant that the safety of such injectors has radically improved over time; nonetheless accidental auto-injection remains a well-recognized problem with an estimated prevalence of circa 1000 cases per year in the United States.^[5] Adult adrenaline auto-injectors typically contain 300 mg of adrenaline at a concentration of 1/1000.^[6] At such concentrations there is a potential risk of digital ischemia progressing to necrosis should the device be injected into the hand or finger as well as severe pain and long term neuropraxia.^[7,8] This is of particular relevance given the vast majority of auto-injector injuries involve the hand or fingers.^[9]

A variety of methods have historically been trailed for adrenaline reversal. The most effective of these is local infiltration with the alpha blocker phentolamine (Walsh et al^[7]). It has been shown to be safe and effective at reversing the effects of adrenaline, restoring circulation almost immediately.^[10,11]

There is significant variation about the reported concentration and dose of phentolamine to be used in such circumstances. Consensus in the literature seems to be between 1 to 5 mg of 0.1% to 0.5% phentolamine.^[12] This information is not provided by the manufacturers of adrenaline auto-injectors nor is it easily available in formularies such as the British National Formulary.

Given the lack of clear and easily accessible information on adrenaline reversal the purpose of this work was to determine knowledge and understanding of the management of auto-injector injuries amongst clinical staff in the emergency department (ED) and hand surgery department of a large urban tertiary hand surgery unit.

2. Materials and methods

We circulated a six question survey to 40 clinicians in a large urban tertiary hand surgery center. Clinicians surveyed included ED doctors, specialist nurses, advanced clinical practitioners and hand surgeons. All clinicians working in the ED or the department of hand surgery were eligible for participation. The survey took the form of an online Survey Monkey Poll distributed to the ED and hand surgery departments. For the survey questions please see supplemental digital content (Appendix 1, Supplemental Digital Content, http://links.lww.com/MD/I489). The study was approved by the governance team of the hospital and participants gave consent for their responses to be used in further research. The survey was made up of six questions with participants selecting pre-determined answers. These assessed demographics, understanding of adrenaline duration of action and its reversal (agent and location within the hospital as well as dose). Responses to each question were described in graph and percentages.

3. Results

There was 100% completion of the survey by each of the 40 respondents.

Demographics: Of the 40 respondents to the survey the majority were hand surgeons (72%). The remaining respondents were made up of ED doctors (18%) and specialist nurses (10%). Please see Figure 1 for a breakdown of demographics.

Figure 1.

Pie chart demonstrating the demographics of survey respondents.

Grade: 15% and 27% of respondents were made up of consultant and trainee hand surgeons respectively. 35% were at a core surgical trainee level and 22.5% were at a foundation year 2 doctor (FY2) level. Specialist nurses and advanced clinical practitioners were taken to be at the equivalent level of skill to an FY2 doctor. Please see Figure 2 for a breakdown of the individual grades.

Figure 2.

Pie chart demonstrating the grade of respondents.

Duration of action: The correct duration of action of adrenaline (4–6 hours) was identified by 25% of respondents. 70% believed It to have a significantly shorter duration of action whilst 5% believed it to last for longer. Please see Figure 3 for a breakdown of the perceived durations of action of adrenaline.

Figure 3.

Bar chart demonstrating the perceived durations of action of adrenaline amongst respondents.

Adrenaline reversal: 50% of respondents correctly identified phentolamine as the first line reversal agent for adrenaline. 15% suggested an alpha blocker and 37.5% did not know or suggested alternative methods. Participants were allowed to select multiple options. Please see Figure 4 for a full breakdown of the range of responses to adrenaline reversal.

Figure 4.

Bar chart demonstrating the perceived options for reversing adrenaline amongst respondents.

Phentolamine dose: Only 20% of respondents were aware of the correct dose for phentolamine. 15% identified an incorrect dose and the majority (65%) did not know. Please refer to Figure 5 for a full breakdown of responses.

Figure 5.

Bar chart demonstrating the dose of phentolamine perceived to be correct for adrenaline reversal amongst respondents.

Location of phentolamine: The correct location of phentolamine was only identified by 2.5% of respondents. 55% selected an incorrect location with 42.5% not knowing. Please refer to Figure 6 for a full breakdown of responses.

Figure 6.

Bar chart demonstrating the range of locations respondents perceived phentolamine to be located in the hospital.

4. Discussion

This study demonstrates that in a major urban hand surgery center knowledge surrounding adrenaline auto-injector injuries is mixed. The half-life of adrenaline is taken to be 43 ± 15 minutes according to the leading auto-injector manufacturer.^[13] This results in a duration of action of between 4 to 6 hours following auto-injection.^[11] Tissue in the extremities will suffer irreversible damage from ischemia if not corrected within 4 to 6 hours.^[14] There is thus a clear correlation between the time to treatment and the risk of digital ischemia progressing to necrosis. In practice many auto-injector injuries are likely to resolve without treatment given the relative resistance of the fingers to ischemic necrosis.^[8] In certain conditions however the risk is much higher. preexisting vascular conditions such as Raynauds significantly reduce the digits’ ability to deal with ischemia and accelerate the progression to necrosis.^[15] The population prevalence of Raynauds is 3% to 5% with significant variation in severity of symptoms.^[16] Given the relatively high prevalence of both Raynauds and auto-injector carriage amongst the general population, it is likely that a small proportion of auto-injector injuries will occur in this significantly more at risk population.

Only 25% of respondents to the survey were aware of the duration of action of adrenaline. The vast majority believed the duration to be significantly shorter. The ischemic tolerance of tissues is now universally recognized with national and international guidelines describing the need to act within 4 to 6 hours to prevent permanent damage.^[17] The assumption that adrenaline lasts less time than it takes for necrosis to occur may lead to an underappreciation of the danger from auto-injector injuries among clinicians. This in turn may lead to a delay in treatment as the time dependent nature of an otherwise mild injury is not recognized during initial triage.

The respondents’ understanding of the reversal of adrenaline was equally mixed. Half were aware of phentolamine being the best reversal agent for adrenaline.^[10] It is established practice in emergency departments to stock the reversal agents to drugs commonly prescribed in the community in an emergency drugs cupboard. Opioids are commonly prescribed in the community and have potentially serious time dependent effects if incorrectly ingested or overdosed. Naloxone rapidly and safely reverses the effects of opioids and is thus routinely available in the ED.^[18] Given the existence of a readily available reversal agent, the prevalence of adrenaline auto-injectors in the community and the time dependent nature of auto-injector injuries; it would be logical to keep a stock of phentolamine in the emergency drug cupboard in the ED.

The cohort’s awareness of the correct phentolamine dosing varied significantly, even amongst those who were familiar with phentolamine. A local infiltration of 1 to 5 mg of 0.1% to 0.5% phentolamine is the consensus in the literature, however, this can only be determined from a literature search. It is not available in easily accessible formularies such as the British National Formulary.^[12] In the time dependent emergency situations where phentolamine administration is necessary, the lack of accessibility to this information is likely to result in a delay in treatment and thus increase the risk of ischemia progressing to necrosis. It is also more likely to result in an incorrect or sub-therapeutic dose being administered due to clinician uncertainty of dosing and a tendency to err on the side of caution with unfamiliar medications.

Knowledge regarding phentolamine storage and location within the hospital was poor. The majority of respondents believed phentolamine is kept in the emergency drug cupboard in the ED. Only one respondent out of forty was aware that it required refrigeration and was kept in the Operating Department drug fridge. According to the manufacturer, phentolamine standard vials should be stored between 2 to 8 degrees Celsius.^[19] It is routinely kept in the Operating Department due to the increasing popularity of the Wide Awake Local Anaesthetic No Tourniquet operating technique which requires injection of adrenaline into the digits to create a bloodless operating field.^[20,21] In an emergency requiring its use, the confusion surrounding phentolamine location is likely to significantly increase the time interval between prescription and administration. Given the time sensitive nature of such emergencies, any such delay may increase the chances of ischemia progressing to necrosis.

In view of the above and the readily available nature of a safe and effective reversal agent, we recommend that all emergency departments should consider stocking phentolamine in the emergency drugs fridge and producing a local guideline for its administration. Such a guideline summarizing the circumstances in which phentolamine is recommended along with the correct dosing should be easily accessible in the ED as a “quick lookup guide” should a patient with an auto-injector injury present to the department. We expect that by doing so we can reduce any delay from prescription to administration and thus reduce the chance of ischemia progressing to necrosis.

5. Limitations

This work is a single center study. Practice and local knowledge varies between centers. The relatively small sample size of 40 participants is less robust than a larger multicentre approach. Future studies would benefit from a larger multi-center approach.

This work consists of a poll of specialist opinion. This only corresponds to level 5 evidence (Oxford Centre for Evidence Based Medicine levels of evidence).

The authors have no funding and conflicts of interest to disclose.

Author contributions

Conceptualization: Pierre William McCaughran, Kate Ellis, Clea Southall, David Zargaran.

Data curation: Kate Ellis.

Investigation: Pierre William McCaughran, Clea Southall.

Project administration: David Zargaran.

Supervision: David Zargaran, Dariush Nikkhah, Afshin Mosahebi.

Writing – original draft: Pierre William McCaughran, Kate Ellis

Writing – review & editing: Pierre William McCaughran, Clea Southall, David Zargaran, Dariush Nikkhah.