Quantification of referrals received at two emergency-capable hyperbaric medicine centers
[ RESEARCH ARTICLE [
Quantification of referrals received at two emergency-capable hyperbaric medicine centers
QUANTIFICATION OF HYPERBARIC REFERRALS
ABSTRACT
Emergency hyperbaric oxygen treatment capability is limited in the United States, and there is little documentation of calls received by 24/7/365 centers. Our study aimed to calculate the number of calls received for urgent hyperbaric oxygen (HBO2). We logged calls from two HBO2 chambers on the East Coast of the United States that serve a densely populated region. The total number of emergency calls was 187 at the University of Maryland (UMD) and 127 at the University of Pennsylvania (UPenn). There were calls on 180 (46%) days during the study period at UMD and 239 (63%) days at UPenn. The most common indication was carbon monoxide toxicity. The peak month of calls was March. Emergency HBO2 calls are common, and more centers need to accept emergency cases. Additional data from geographically diverse centers would add generalizability to these results and capture more diving-related emergencies.
Keywords: epidemiology; hyperbaric facilities; hyperbaric oxygen; intensive care medicine; medical conditions and problems
Key points: A trend toward inadequate emergency hyperbaric oxygen therapy availability has recently been discussed. Calls received at two academic emergency-capable hyperbaric medicine centers were recorded for one year. Timing, quantity, and distribution of calls might aid in better-understanding healthcare needs regarding emergent hyperbaric oxygen therapy.
INTRODUCTION
Emergency hyperbaric oxygen (HBO2) therapy capability is limited in the United States. There are an estimated 70,000 patients per year with indications for emergency hyperbaric oxygen therapy, and there is a present concern for inadequate access to facilities with emergency HBO2 capabilities. Also of great concern is the decreasing number of facilities offering 24/7 emergent HBO2 [1]. The timing, quantity, and distribution of calls might aid in better-understanding healthcare needs regarding emergent hyperbaric oxygen therapy.
Hyperbaric oxygen treatment is indicated for a variety of emergent indications. A non-exhaustive list of these indications includes decompression illness (DCI), iatrogenic gas embolism, acute carbon monoxide poisoning, multiple types of necrotizing infections, failing surgical flaps or grafts, and central retinal artery occlusion (CRAO). While the pathophysiology of these disease states varies greatly, a common factor exists in that a delay in HBO2 can drastically reduce or even eliminate the potential therapeutic benefits. Permanent neurologic disability in cases of DCI or gas embolism and blindness in the cases of CRAO can result from delay or frank unavailability of HBO2. Loss of limb, need for additional operations, and increased mortality can occur without HBO2 for surgical infectious diseases such as necrotizing fasciitis [1-5].
While the overall issue is the limited and declining availability of emergency-capable hyperbaric facilities, the objective of the present report was to quantify calls and to evaluate the ability of two 24/7 emergency-capable HBO2 centers to field calls and provide appropriate care for emergent cases within currently established catchment areas. Documenting case volumes may contribute to the discussion regarding the widespread and growing need for emergency-capable HBO2 facilities.
METHODS
Calls received at two academic emergency-capable hyperbaric medicine centers were recorded for one year. The first call regarding any patient was recorded. The date, time, whether patients received HBO2, indications for treatment, and staff availability were recorded. Off hours were defined as weekends, federal holidays when the center is closed for non-emergencies, and outside of 8 a.m. to 5 p.m. on weekdays. Each site reviewed the data with dive logs and daily conversations with on-call physicians to ensure accuracy. A descriptive analysis was performed. The study was exempt from the UMD Institutional Review Board.
RESULT
There were calls on 180 (46%) days during the study period at UMD and 239 (63%) days at UPenn (Table 1). The total number of urgent calls was 187 at UMD STC and 127 at UPenn. UMD is a receiving center for soft tissue infections, skewing the number of necrotizing fasciitis. Treatment delays were due to patient transfer from outside facilities or lack of staffing. Non-Diabetic chronic wounds were the most common off-label reason for consultation requests. Diabetic ulcers were the most common non-urgent indication for the call. There were 60 (47%) calls during off hours at UPenn and 118 (63%) off-hours calls at UMD. Four percent of emergency calls were not treated at UMD due to inside tender residual nitrogen time and inability to treat. In contrast, 12% of calls were deferred at UPenn due to a lack of a second layer of on-call staffing.
DISCUSSION
This study suggests a large volume of emergent calls for hyperbaric oxygen treatment without the ability to meet demands by two academic centers in a large, densely populated catchment area of the United States. Though it is a small proportion of cases (12% at UPenn, and 4% at UMD), the unavailability or delay of HBO2 has major implications for morbidity and can result in permanent neurologic deficits, vision loss, or tissue and limb loss. In severe necrotizing infections and AGE cases, unavailability of HBO2 can be fatal.
Differences in the number of calls and the proportion of urgent calls were noted between the two centers. The most likely reasons for some of these differences are as follows: UMD STC is a statewide receiving center for necrotizing fasciitis cases, UPenn does not treat CRAO at the time of this writing, and UMD STC is involved in an HBO2 for IBD study which UPenn is not.
The Undersea and Hyperbaric Medical Society (UHMS) reports approximately 1,300 hyperbaric oxygen facilities in the United States [1]. There has been an observed decline in emergency-capable HBO2 facilities in recent decades, and it is estimated that less than 10% of HBO2 facilities currently offer treatments for emergent indications with 24/7 availability [1,6]. As discussed in the recent open letter and white paper by Butler and Moon, many factors contribute to facilities not offering emergent HBO2. These include staffing shortages, lack of critical care and hyperbaric fellowship training, 24/7 call availability, and insurance reimbursement [1].
While the emergency-capable multiplace chambers are few and far between, monoplace facilities focused on wound care are relatively abundant. Very few of these accept after hours calls or are presently set up to treat emergent cases on an on-call basis. Barriers to emergency cases being accepted by these facilities include staffing, reimbursement structure for on-call hours and reimbursement structures for the treatment of emergency HBO2 indications. Emergent cases also potentially displace more definitively reimbursable and pre-approved routine cases.
Staffing models exist in emergency-capable hyperbaric facilities which operate exclusively with monoplace chambers [7]. Treatment tables also differ slightly in acute care in monoplace chambers. Staffing models, treatment tables, and reimbursement plans could be adopted from these emergency facilities to other monoplace facilities to care for emergency HBO2 cases.
While there are limitations to providing critical care in a monoplace chamber, mild to moderate acuity cases for acute indications such as carbon monoxide poisoning could be safely treated in a monoplace chamber. High acuity and true critical care cases (i.e., mechanically ventilated patients) are likely appropriate to be diverted to a multiplace facility. However, there are examples of monoplace practices and facilities where even the sickest of patients are safely and effectively treated in a monoplace chamber. Mild to moderate emergency HBO2 cases being treated at monoplace facilities could offset the resource discrepancy noted at multi-place facilities.
As new indications emerge, the disparity between emergency-capable HBO2 facilities and emergency cases may also grow. Central retinal artery occlusion is a recently approved indication that has not yet ubiquitously integrated into HBO2 practices. More chambers adopting treatment of these cases could exacerbate the strain on existing facilities. Other emerging indications presently being studied, including severe TBI and severe inflammatory bowel disease, also have the potential to increase the need for emergency chambers.
According to CDC data, winter months are the most active for carbon monoxide poisoning, and assistance from monoplace chambers to treat emergencies during those months would off-load the burden on the few multiplace chambers for off-hour emergencies and more seriously ill patients [8,9]. This would decrease time to therapy in many cases as monoplace centers are often bypassed en route to the more geographically sparse multiplace centers. Decreasing the time to treatment would be valuable for patient outcomes. Seasonal partnerships and agreements between multi-place and mono-place facilities such that mono-place facilities accepted select cases in peak months could potentially re-distribute case volume. Of note, our call volume by month (Figure 1) did not demonstrate definitive peaks in the fall and winter, as previously reported in data regarding carbon monoxide poisoning [8,9]. This was potentially due to a relatively small, two-center dataset and the inclusion of non-seasonal diagnoses such as necrotizing fasciitis.
Another potential solution, where financially feasible, would be the installation of one to two monoplace chambers at multiplace facilities. The most frequent reason for staff unavailability in the present report was residual nitrogen time (RNT) for inside tenders. If mild to moderate cases were treated in an on-site monoplace chamber, tenders would not accumulate RNT. They could then be available for high acuity cases more readily treated in the multiplace chamber.
While we surveyed two busy urban multiplace centers, our study is limited for generalizability. HBO2 practice and referral patterns can vary substantially between facilities. Differing geography can also contribute to referral patterns. For instance, cold, northern regions where HVAC and generator use are commonplace can potentially have more carbon monoxide cases while coastal facilities are likely to have more DCI cases. Additional data from geographically diverse hyperbaric facilities would contribute to a broader picture of the state of emergency centers in the US.
CONCLUSION
There is a growing disparity between the need for emergent HBO2 and facilities which offer 24/7 HBO2 for emergent cases. Emergency HBO2 calls are common, and a proportion of cases are left untreated or delayed due to lack of chamber availability. More centers must accept urgent and emergency cases to provide adequate hyperbaric oxygen treatments to patients who require it urgently.
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