Management of Suspected Fluid Balance Issues in Participants of Wilderness Endurance Events.

Dehydration and exercise-associated hyponatremia (EAH) are both relatively common conditions during wilderness endurance events. Whereas dehydration is treated with fluids, EAH is appropriately managed with fluid restriction and a sodium bolus but can worsen with isotonic or hypotonic fluids. Therefore, caution is recommended in the provision of postevent rehydration in environments where EAH is a potential consideration because accurate field assessment of hydration status can be challenging, and measurement of blood sodium concentration is rarely possible in the wilderness. Dehydration management with oral rehydration is generally adequate and preferred to intravenous rehydration, which should be reserved for athletes with sustained orthostasis or inability to tolerate oral fluid ingestion after some rest. In situations where intravenous hydration is initiated without known blood sodium concentration or hydration status, an intravenous concentrated sodium solution should be available in the event of acute neurological deterioration consistent with the development of EAH encephalopathy.

Is it Appropriate for Patients to be Discharged at the Scene by Paramedics?

BACKGROUND: Outcomes of patients who are discharged at the scene by paramedics are not fully understood. OBJECTIVE: We aimed to describe the risk of re-presentation and/or death in prehospital patients discharged at the scene. METHODS: We conducted a retrospective cohort study using linked ambulance, emergency department (ED), and death data. We compared outcomes in patients who were discharged at the scene by paramedics with those who were transported to ED by paramedics and then discharged from ED between January 1 and December 31, 2013 in metropolitan Perth, Western Australia. Occurrences of subsequent ambulance requests, ED attendance, hospital admission and death were compared between those discharged at the scene and those discharged from ED. RESULTS: There were 47,330 patients during the study period, of whom 19,732 and 27,598 patients were discharged at the scene and from ED, respectively. Compared to those discharged from ED, those discharged at the scene were more likely to subsequently: request an ambulance (6.1% vs. 1.8%, adjusted odds ratio [adj OR] 3.4; 95% confidence interval [CI] 3.0-3.9), attend ED (4.6% vs. 1.4%, adj OR 3.3; 95% CI 2.8-3.8), be admitted to hospital (3.3% vs. 0.8%, adj OR 4.2; 95% CI 3.4-5.1). Those discharged at the scene tended towards an increased likelihood of death (0.2% vs. 0.1%, adj OR 1.8; 95% CI 0.99-3.2) within 24 hours of discharge compared to those discharged from ED. CONCLUSION: Patients attended by paramedics who were discharged at the scene had more subsequent events than those who were transported to and discharged from ED. Further consideration needs to be given to who is suitable to be discharged at the scene by paramedics.

Exercise-associated hyponatremic encephalopathy in an endurance open water swimmer.

Exercise-associated hyponatremia and its more serious form, known as exercise-associated hyponatremic encephalopathy, are recognized as some of the most important medical problems seen in a variety of different forms of endurance exercise. We describe a case of exercise-associated hyponatremic encephalopathy presenting as altered conscious state and seizures in a woman who had completed a 20-km open ocean swim. Her serum sodium measured approximately 1 hour after her seizure was 119 mmol/L on point-of-care testing. With ongoing critical care support and the use of hypertonic saline, she was able to be extubated the next day, neurologically intact, and ultimately was discharged from hospital without neurological sequelae. This case emphasizes both the importance of considering exercise-associated hyponatremic encephalopathy as a cause of neurological impairment in all athletes and the pivotal role of hypertonic saline in the treatment of this condition.

The need for salt: does a relationship exist between cystic fibrosis and exercise-associated hyponatremia?

Salt replacement is often recommended to prevent exercise-associated hyponatremia (EAH) despite a lack of evidence to support such practice. Exercise-associated hyponatremia is known to be a complex process resulting from the interplay of hydration, arginine vasopressin, and sodium balance. Although evidence suggests overhydration is the dominant pathophysiologic factor in most cases, the contributions of sweat sodium losses remain unclear. A theoretical genetic mechanism producing exuberant sweat sodium loss in athletes is the presence of cystic fibrosis (CF) gene. Individuals with CF develop hypovolemic hyponatremia by sodium loss via sweat through a defective chloride ion transport channel, the CF transmembrane conductance regulator (CFTR). Elevated sweat sodium concentrations in CF single heterozygotes suggest that athletes developing EAH may be CFTR carriers. We targeted the 2010 and 2011 Western States Endurance Run ultramarathon, an event where athletes with EAH regularly present in a hypovolemic state, for a cohort maximizing the potential to document such a relationship. A total of 798 runners started the 2010 (n = 423) and 2011 (n = 375) races. Of the 638 finishers, 373 were screened for EAH by blood draw, 60 (16%) were found to have EAH, and 31 (alpha = 0.05 for n = 9) reported their CF result from a saliva-based genetic testing kit. Neither the 31 EAH-positive athletes nor the 25 EAH-negative comparison cohort athletes tested positive for a CF mutation. This null relationship suggests that CFTR mutations are not associated with the development of EAH and that salt supplementation is unnecessary for such a reason.

Wilderness Medical Society practice guidelines for treatment of exercise-associated hyponatremia: 2014 update.

Exercise-associated hyponatremia (EAH) is defined by a serum or plasma sodium concentration below the normal reference range of 135 mmol/L that occurs during or up to 24 hours after prolonged physical activity. It is reported to occur in individual physical activities or during organized endurance events conducted in austere environments in which medical care is limited and often not available, and patient evacuation to definitive care is often greatly delayed. Rapid recognition and appropriate treatment are essential in the severe form to ensure a positive outcome. Failure in this regard is a recognized cause of event-related fatality. In an effort to produce best practice guidelines for EAH in the austere environment, the Wilderness Medical Society convened an expert panel. The panel was charged with the development of evidence-based guidelines for management of EAH. Recommendations are made regarding the situations when sodium concentration can be assessed in the field and when these values are not known. These recommendations are graded on the basis of the quality of supporting evidence and balance between the benefits and risks/burdens for each parameter according to the methodology stipulated by the American College of Chest Physicians. This is an updated version of the original WMS Practice Guidelines for Treatment of Exercise-Associated Hyponatremia published in Wilderness & Environmental Medicine 2013;24(3):228-240.

Evidence-based paramedic models of care to reduce unnecessary emergency department attendance--feasibility and safety.

BACKGROUND: As demand for Emergency Department (ED) services continues to exceed increases explained by population growth, strategies to reduce ED presentations are being explored. The concept of ambulance paramedics providing an alternative model of care to the current default 'see and transport to ED' has intuitive appeal and has been implemented in several locations around the world. The premise is that for certain non-critically ill patients, the Extended Care Paramedic (ECP) can either 'see and treat' or 'see and refer' to another primary or community care practitioner, rather than transport to hospital. However, there has been little rigorous investigation of which types of patients can be safely identified and managed in the community, or the impact of ECPs on ED attendance. METHODS/DESIGN: St John Ambulance Western Australia paramedics will indicate on the electronic patient care record (e-PCR) of patients attended in the Perth metropolitan area if they consider them to be suitable to be managed in the community. 'Follow-up' will examine these patients using ED data to determine the patient's disposition from the ED. A clinical panel will then develop a protocol to identify those patients who can be safely managed in the community. Paramedics will then assess patients against the derived ECP protocols and identify those deemed suitable to 'see and treat' or 'see and refer'. The ED disposition (and other clinical outcomes) of these 'ECP protocol identified' patients will enable us to assess whether it would have been appropriate to manage these patients in the community. We will also 'track' re-presentations to EDs within seven days of the initial presentation. This is a 'virtual experiment' with no direct involvement of patients or changes in clinical practice. A systems modelling approach will be used to assess the likely impact on ED crowding. DISCUSSION: To date the efficacy, cost-effectiveness and safety of alternative community-based models of emergency care have not been rigorously investigated. This study will inform the development of ECP protocols through the identification of types of patient presentation that can be considered both safe and appropriate for paramedics to manage in the community.

Wilderness Medical Society practice guidelines for treatment of exercise-associated hyponatremia.

Exercise-associated hyponatremia (EAH) typically occurs during or up to 24 hours after prolonged physical activity, and is defined by a serum or plasma sodium concentration below the normal reference range of 135 mEq/L. It is also reported to occur in individual physical activities or during organized endurance events conducted in austere environments in which medical care is limited or often not available, and patient evacuation to definitive care is often greatly delayed. Rapid recognition and appropriate treatment are essential in the severe form to ensure a positive outcome. Failure in this regard is a recognized cause of event-related fatality. In an effort to produce best practice guidelines for EAH in the austere environment, the Wilderness Medical Society convened an expert panel. The panel was charged with the development of evidence-based guidelines for management of EAH. Recommendations are made regarding the situations when sodium concentration can be assessed in the field and when these values are not known. These recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens for each parameter according to the methodology stipulated by the American College of Chest Physicians.

Increasing creatine kinase concentrations at the 161-km Western States Endurance Run.

OBJECTIVE: Very high blood creatine kinase (CK) concentrations have been observed among recent finishers of the 161-km Western States Endurance Run (WSER), and it has been suggested that there is a link between rhabdomyolysis and hyponatremia. Therefore, the purpose of this study was to compare CK concentrations of finishers in the 2010 WSER with past values, and to determine whether there was an association between blood CK and sodium concentrations. METHODS: Consenting 2010 WSER finishers provided blood samples at the finish for determination of blood CK and sodium concentrations. Finish time, age, and gender were obtained from official race results, and running experience was determined from our database as number of prior 161-km ultramarathon finishes. RESULTS: From 216 (66%) of the 328 finishers, median and mean CK concentrations were found to be 20 850 IU/L and 32 956 IU/L, respectively (range 1500-264 300 IU/L), and 13 (6%) had values greater than 100 000 IU/L. These values were statistically higher (P < .0001) than those reported from the 1995 WSER. The CK concentration was not significantly associated with finish time, age, gender, or running experience. Blood sodium concentrations were obtained from a subgroup of 159 runners, and the relationship between blood CK and sodium concentrations did not reach statistical significance (P = .06, r = -0.12). CONCLUSIONS: Creatine kinase concentrations of 2010 WSER finishers are higher than values previously reported. More research should focus on explaining this observation and on whether there is a possible link between higher CK concentrations and hyponatremia.

Race diet of finishers and non-finishers in a 100 mile (161 km) mountain footrace.

OBJECTIVE: To determine if food and fluid intake is related to completion of a 161-km ultramarathon. METHODS: Sixteen consenting runners in the Western States Endurance Run participated in the study. Race diets were analyzed using Nutritionist Pro software. Both total intake and intake by race segment (3 total) were evaluated. RESULTS: Six of 16 subjects completed the race (finishers) in 27.0 ± 2.3 hours (mean ± SD). Non-finishers completed 96.5 ± 20.5 km in 17.0 ± 3.9 h. Overall consumption rates of kilocalories, carbohydrate, fat, and sodium were significantly greater (P < 0.05) in finishers (4.6 ± 1.7 kcal/kg/h, 0.98 ± 0.43 g carbohydrate/kg/h, 0.06 ± 0.03 g fat/kg/h, 10.2 ± 6.0 mg sodium/kg/h) versus non-finishers (2.5 ± 1.3 kcal/kg/h, 0.56 ± 0.32 g carbohydrate/kg/h, 0.02 ± 0.02 g fat/kg/h, 5.2 ± 3.0 mg sodium/kg/h). Kilocalorie, fat, fluid, and sodium consumption rates during segment 1 (first 48 km) were significantly greater in finishers than in non-finishers. CONCLUSIONS: Completion of this 161-km race was related to greater fuel, fluid, and sodium consumption rates. However, intake ranges for the finishers were large, so factors other than race diet may have contributed to the successful completion of the race.

An intervention study of oral versus intravenous hypertonic saline administration in ultramarathon runners with exercise-associated hyponatremia: a preliminary randomized trial.

OBJECTIVE: To determine whether asymptomatic exercise-associated hyponatremia (EAH) in ultramarathon runners can be corrected with either oral or intravenous (IV) 3% hypertonic saline (HTS). DESIGN: Prospective with randomization into 1 of 2 intervention arms. SETTING: Western States (161 km) Endurance Run, California. PARTICIPANTS: Forty-seven finishers in the event consented to be screened to identify those with EAH, defined as plasma sodium ([Na]p) <135 mmol/L at race end. INTERVENTIONS: Participants with EAH but without symptoms were randomized to receive a single 100 mL dose of either oral or IV 3% HTS. Blood was drawn before intervention and at 60 minutes postintervention to measure [Na]p, and concentrations of plasma potassium, proteins, and arginine vasopressin (AVP). Body mass, percent total body water, and percent body fat were measured prerace and postrace using impedance scales. MAIN OUTCOME MEASURES: Change in [Na]p. RESULTS: Fourteen of 47 consenting finishers (30%) had EAH. Eight agreed to be randomized into the intervention protocol. Only in the IV group did [Na]p change significantly (from 130.8 to 134.6 mmol/L) over the 60 minutes post-HTS administration. Elevated AVP concentrations were seen at race finish in both the groups and remained so after HTS treatment. CONCLUSIONS: In this preliminary trial, prompt administration of a 100 mL bolus of IV 3% HTS was associated with normalization of [Na]p in asymptomatic EAH, but a similar effect was not demonstrated for the same dose orally. Elevated AVP levels were observed and may play a part in the development of EAH but were not suppressed significantly by either intervention.

Changes in copeptin and bioactive vasopressin in runners with and without hyponatremia.

OBJECTIVE: To evaluate changes in both the N-terminal (arginine vasopressin; AVP) and C-terminal (copeptin) fragments of the vasopressin prohormone before, during, and after an ultramarathon race and to assess vasopressin and copeptin concentrations in runners with and without hyponatremia. DESIGN: Observational study. SETTING: Three trials (2 sodium balance and 1 hyponatremia treatment) in 2 separate approximately 160-km footraces [Western States Endurance Run (WSER) and Javelina Jundred (JJ100)]. PARTICIPANTS: Six hyponatremic and 20 normonatremic runners; 19 finishers with 7 completing 100 km. MAIN OUTCOME MEASURES: Plasma AVP ([AVP]p), copeptin ([copeptin]p), sodium ([Na]p), and protein (%plasma volume change; %PV) concentrations. RESULTS: In the WSER Sodium Trial, a 3-fold prerace to postrace increase in both [AVP]p (0.7 ± 0.4 to 2.7 ± 1.9 pg/mL; P < 0.05) and [copeptin]p (10.3 ± 12.5 to 28.2 ± 16.3 pmol/L; nonsignificant) occurred, despite a 2 mEq/L decrease in [Na]p (138.7 ± 2.3 to 136.7 ± 1.6 mEq/L; NS). A significant correlation was noted between [AVP]p and [copeptin]p postrace (r = 0.82; P < 0.05). In the WSER Treatment Trial, despite the presence of hyponatremia pretreatment versus posttreatment ([Na]p = 130.3 vs 133.5 mEq/L, respectively), both [AVP]p (3.2 vs 2.1 pg/mL) and [copeptin]p (22.5 vs 24.9 pmol/L) were well above the detectable levels. A significant correlation was noted between [AVP]p and [copeptin]p 60 minutes after treatment (r = 0.94; P < 0.05). In the JJ100 Sodium Trial, significant correlations were found between [copeptin]p change and %PV change (r = -0.34; P < 0.05) and between [AVP]p change and [Na]p change (r = 0.39; P < 0.05) but not vice-versa. CONCLUSIONS: [Copeptin]p seems to be a reliable surrogate of stimulated [AVP]p during exercise. Nonosmotic vasopressin stimulation occurs during ultradistance running. [Copeptin]p may better reflect chronic (%PV) vasopressin secretion under conditions of endurance exercise.

Battlefield acupuncture added no benefit as an adjunct analgesic in emergency department for abdominal, low back or limb trauma pain.

OBJECTIVES: To ascertain whether ear acupuncture (modified Battlefield technique) as an adjunct (Adj-BFA) to standard analgesia care (SAC) significantly reduces pain scores compared with sham acupuncture (Adj-Sham) or SAC alone, when delivered by medical and nursing practitioners in an ED. METHODS: A randomised controlled trial using a convenience sample of 90 patients attending an ED with acute abdominal, limb trauma or low back pain were allocated to three treatment arms: Adj-BFA, Adj-Sham and SAC. The primary outcome of change in pain scores out-of-10 (NPRS-10) from triage were assessed immediately after intervention and at 1 and 2 h post-intervention. Secondary outcomes were the percentage of patients reporting 'adequate analgesia' or ≥30% reduction in pain score, analgesic medication use (in morphine equivalent dose [milligrammes]), analgesics and needle costs (Australian dollars), adverse effects and patient satisfaction (Likert scale). RESULTS: There was no significant difference in pain scores (P = 0.582) or secondary outcomes measures between Adj-BFA, Adj-Sham and SAC. CONCLUSION: The present study on 90 patients did not show a significant difference in analgesia outcomes in the first 2 h using Adj-BFA for acute pain in the ED, and there were no significant differences for secondary outcomes between treatment arms. Given the mixed results of recent BFA trials, further research using the original BFA technique on different painful conditions, as either stand-alone or as-adjunct to non-opioid analgesia are needed before BFA can be recommended as a technique for acute pain management in the ED.

Rhabdomyolysis and hyponatremia: a cluster of five cases at the 161-km 2009 Western States Endurance Run.

OBJECTIVE: Five of 400 starters of the 2009 Western States Endurance Run (WSER) were hospitalized with hyponatremia and rhabdomyolysis. This article explores the risk factors associated with development of hyponatremia and rhabdomyolysis. METHODS: Data on the 5 cases were collected retrospectively from the runners and medical records, and all race participants were invited to complete a post-race survey. Characteristics of the cases were compared with the other race participants. RESULTS: The 5 runners developing hyponatremia with rhabdomyolysis were men with a mean (±SD) age of 39 ± 7 years. Presenting complaints included neurological symptoms among 3 and nausea among 3. Compared with those runners not developing hyponatremia with rhabdomyolysis, the cases tended to be younger, faster, more likely to have sustained an injury which interfered with training prior to the race, and were more likely to use nonsteroidal anti-inflammatory drugs (NSAIDs) during the race. The 3 of 5 cases progressing to acute renal failure were characterized by higher initial blood urea nitrogen (BUN; 43-69 vs 18-23 mg/dL) and creatinine (2.8-4.9 vs 1.1-1.2 mg/dL) levels but were not distinguished by creatinine phosphokinase (CPK) concentrations. CONCLUSIONS: Over 1% of participants in the 2009 WSER were hospitalized with hyponatremia in combination with rhabdomyolysis. These individuals tended to be younger, faster, more likely to have had an injury that interfered with training, and more likely to have used NSAIDs during the race. Higher initial BUN and creatinine levels, but not CPK concentrations, distinguished those 3 who progressed to acute renal failure.

Why do paramedics choose to bring patients to a private emergency department?

OBJECTIVE: While prior experience, favourable location and anticipation of high quality care are known to influence patient choice to attend a private ED, it is likely that decision-making is also influenced by other persons. In particular, patients arriving by ambulance are under the care of paramedics, whose values towards healthcare and rationale for choosing one ED over another have not been studied. This study aimed to describe reasons why paramedics choose to bring patients to a private ED. METHODS: Exploratory, qualitative study using semi-structured, face-to-face interviews with paramedics bringing patients to a private ED from the community. Two primary questions reinforced by structured prompts were asked: 'Why did you choose to come to this emergency department?' and 'What are your general expectations of this emergency department visit?' Interviews were audio recorded, transcribed verbatim and analysed thematically. RESULTS: Fifty paramedics were interviewed with 48 interviews able to be transcribed and used in analysis. Four factors were identified to increase the likelihood of a private ED destination: specific direction, institutional allegiance, hospital logistics and systems and receiving hospital service ethos. CONCLUSIONS: Paramedics take into consideration when possible patient's wishes and are more likely to bring a patient to a private ED if they have specific direction from the patient or the patient's family or GP. The likelihood of presenting to a private ED is increased if the patient has an allegiance with the facility and the paramedics perceive favourably the hospital logistics and systems as well as service ethos.