Medical resuscitations in rugged prehospital settings require emergency personnel to perform high-risk procedures in low-resource conditions. Just-in-Time Guidance (JITG) utilizing augmented reality (AR) guidance may be a solution. There is little literature on the utility of AR-mediated JITG tools for facilitating the performance of emergent field care.

The objective of this study was to investigate the feasibility and efficacy of a novel AR-mediated JITG tool for emergency field procedures.

Emergency medical technician-basic (EMT-B) and paramedic cohorts were randomized to either video training (control) or JITG-AR guidance (intervention) groups for performing bag-valve-mask (BVM) ventilation, intraosseous (IO) line placement, and needle-decompression (Needle-d) in a medium-fidelity simulation environment. For the interventional condition, subjects used an AR technology platform to perform the tasks. The primary outcome was participant task performance; the secondary outcomes were participant-reported acceptability. Participant task score, task time, and acceptability ratings were reported descriptively and compared between the control and intervention groups using chi-square analysis for binary variables and unpaired t-testing for continuous variables.

Sixty participants were enrolled (mean age 34.8 years; 72% male). In the EMT-B cohort, there was no difference in average task performance score between the control and JITG groups for the BVM and IO tasks; however, the control group had higher performance scores for the Needle-d task (mean score difference 22%; P = .01). In the paramedic cohort, there was no difference in performance scores between the control and JITG group for the BVM and Needle-d tasks, but the control group had higher task scores for the IO task (mean score difference 23%; P = .01). For all task and participant types, the control group performed tasks more quickly than in the JITG group. There was no difference in participant usability or usefulness ratings between the JITG or control conditions for any of the tasks, although paramedics reported they were less likely to use the JITG equipment again (mean difference 1.96 rating points; P = .02).

This study demonstrated preliminary evidence that AR-mediated guidance for emergency medical procedures is feasible and acceptable. These observations, coupled with AR’s promise for real-time interaction and on-going technological advancements, suggest the potential for this modality in training and practice that justifies future investigation.

Pediatric patients transferred by Emergency Medical Services (EMS) from urgent care (UC) and office-based physician practices to the emergency department (ED) following activation of the 9-1-1 EMS system are an under-studied population with scarce literature regarding outcomes for these children. The objectives of this study were to describe this population, explore EMS level-of-care transport decisions, and examine ED outcomes.

This was a retrospective review of patients zero to <15 years of age transported by EMS from UC and office-based physician practices to the ED of two pediatric receiving centers from January 2017 through December 2019. Variables included reason for transfer, level of transport, EMS interventions and medications, ED medications/labs/imaging ordered in the first hour, ED procedures, ED disposition, and demographics. Data were analyzed with descriptive statistics, X2 test, point biserial correlation, two-sample z test, Mann-Whitney U test, and 2-way ANOVA.

A total of 450 EMS transports were included in this study: 382 Advanced Life Support (ALS) runs and 68 Basic Life Support (BLS) runs. The median patient age was 2.66 years, 60.9% were male, and 60.7% had private insurance. Overall, 48.9% of patients were transported from an office-based physician practice and 25.1% were transported from UC. Almost one-half (48.7%) of ALS patients received an EMS intervention or medication, as did 4.41% of BLS patients. Respiratory distress was the most common reason for transport (46.9%). Supplemental oxygen was the most common EMS intervention and albuterol was the most administered EMS medication. There was no significant association between level of transport and ED disposition (P = .23). The in-patient admission rate for transported patients was significantly higher than the general ED admission rate (P <.001).

This study demonstrates that pediatric patients transferred via EMS after activation of the 9-1-1 system from UC and medical offices are more acutely ill than the general pediatric ED population and are likely sicker than the general pediatric EMS population. Paramedics appear to be making appropriate level-of-care transport decisions.

Hyperkalemia (HK) is common and potentially a life-threatening condition. If untreated, HK can progress to ventricular arrhythmia and cardiac arrest. Early treatment reduces mortality in HK. This study evaluates a novel protocol for identification and empiric management of presumed HK in the prehospital setting.

This was a retrospective, observational chart review of a single, large, suburban Emergency Medical Services (EMS) system. Patients treated for presumed HK, with both a clinical concern for HK and electrocardiogram (ECG) changes consistent with HK, from February 2018 through February 2021 were eligible for inclusion. Patients were excluded if found to be in cardiac arrest on EMS arrival. Empiric treatment of HK included administration of calcium, sodium bicarbonate, and albuterol. Post-treatment, patients were placed on cardiac monitoring and adverse events recorded enroute to receiving hospital. Protocol compliance was assessed by two independent reviewers. Serum potassium (K) level was obtained from hospital medical records.

A total of 582 patients were treated for HK, of which 533 patients were excluded due to cardiac arrest prior to EMS arrival. The remaining 48 patients included in the analysis had a mean age of 56 (SD = 20) years and were 60.4% (n = 29) male with 77.1% (n = 37) Caucasian, 10.4% (n = 5) African American, and 12.5% (n = 6) Hispanic. Initial blood draw at the receiving facilities showed K >5.0mEq/L in 22 (45.8%), K of 3.5-5.0mEq/L in 23 (47.9%), and K <3.5mEq/L in three patients (6.3%). Independent review of the EMS ECG found the presence of hyperkalemic-related change in 43 (89.6%) cases, and five (10.4%) patients did not meet criteria for treatment due to lack of either appropriate ECG findings or clinical suspicion. No episodes of unstable tachyarrhythmia or cardiac arrest occurred during EMS treatment or transport.

The study evaluated a novel protocol for detecting and managing HK in the prehospital setting. It is feasible for EMS crews to administer this protocol, although a larger study is needed to make the results generalizable.

Non-physician performed point-of-care ultrasound (POCUS) is emerging as a diagnostic adjunct with the potential to enhance current practice. The scope of POCUS utility is broad and well-established in-hospital, yet limited research has occurred in the out-of-hospital environment. Many physician-based studies expound the value of POCUS in the acute setting as a therapeutic and diagnostic tool. This study utilized a scoping review methodology to map the literature pertaining to non-physician use of POCUS to improve success of peripheral intravenous access (PIVA), especially in patients predicted to be difficult to cannulate.

Ovid MEDLINE, CINAHL Plus, EMBASE, and PubMed were searched from January 1, 1990 through April 15, 2021. A thorough search of the grey literature and reference lists of relevant articles was also performed to identify additional studies. Articles were included if they examined non-physician utilization of ultrasound-guided PIVA (USGPIVA) for patients anticipated to be difficult to cannulate.

A total of 158 articles were identified. A total of 16 articles met the inclusion criteria. The majority of participants had varied experience with ultrasound, making accurate comparison difficult. Training and education were non-standardized, as was the approach to determining difficult intravenous access (DIVA). Despite this, the majority of the studies demonstrated high first attempt and overall success rates for PIVA performed by non-physicians.

Non-physician USGPIVA appears to be a superior method for PIVA when difficulty is anticipated. Additional benefits include reduced requirement for central venous catheter (CVC) or intraosseous (IO) needle placement. Paramedics, nurses, and emergency department (ED) technicians are able to achieve competence in this skill with relatively little training. Further research is required to explore the utility of this practice in the out-of-hospital environment.

Excited delirium, which has been defined as combativeness, agitation, and altered sensorium, requires immediate treatment in prehospital or emergency department (ED) settings for the safety of both patients and caregivers. Prehospital ketamine use is prevalent, although the evidence on safety and efficacy is limited. Many patients with excited delirium are intoxicated with illicit substances. This investigation explores whether patients treated with prehospital ketamine for excited delirium with concomitant substance intoxication have higher rates of subsequent intubation in the ED compared to those without confirmed substance usage.

Over 28 months at two large community hospitals, all medical records were retrospectively searched for all patients age 18 years or greater with prehospital ketamine intramuscular (IM) administration for excited delirium and identified illicit and prescription substance co-ingestions. Trained abstractors collected demographic characteristics, history of present illness (HPI), urine drug screens (UDS), alcohol levels, and noted additional sedative administrations. Substance intoxication was determined by UDS and alcohol positivity or negativity, as well as physician HPI. Patients without toxicological testing or documentation of substance intoxication, or who may have tested positive due to ED sedation, were excluded from relevant analyses. Subsequent ED intubation was the primary pre-specified outcome. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to compare variables.

Among 86 patients given prehospital ketamine IM for excited delirium, baseline characteristics including age, ketamine dose, and body mass index were similar between those who did or did not undergo intubation. Men had higher intubation rates. Patients testing positive for alcohol, amphetamines, barbiturates, benzodiazepines, ecstasy, marijuana, opiates, and synthetic cathinones, both bath salts and flakka, had similar rates of intubation compared to those negative for these substances. Of 27 patients with excited delirium and concomitant cocaine intoxication, nine (33%) were intubated compared with four of 50 (8%) without cocaine intoxication, yielding a 5.75 OR (95%, CI 1.57 to 21.05; P = .009).

Patients treated with ketamine IM for excited delirium with concomitant cocaine intoxication had a statistically significant 5.75-fold increased rate of subsequent intubation in the ED. Amongst other substances, no other trends with intubation were noted, but further study is warranted.

Prehospital intramuscular (IM) ketamine is increasingly used for chemical restraint of agitated patients. However, few studies have assessed emergency department (ED) follow-up of patients receiving prehospital ketamine for this indication, with previous reports suggesting a high rate of post-administration intubation. This study examines the rate of and reasons for intubation and other airway interventions in agitated patients who received ketamine by Emergency Medical Services (EMS).

This retrospective cohort study included patients who received prehospital ketamine for agitation and were transported to two community hospital EDs. Charts were reviewed for demographics, ketamine dose, and airway intervention by EMS or in the ED. Characteristics of patients who were intubated versus those who did not receive airway intervention were analyzed.

Over 28 months, 86 patients received ketamine for agitation. Fourteen (16.3%) underwent endotracheal intubation. Patients with a higher temperature and a lower Glasgow Coma Score (GCS) were more likely to require intubation. There was no age or dose-dependent association on intubation rate. Intubated patients averaged 39 years old versus 44 for patients not intubated (negative five-year difference; 95% CI, -16 to 6). The mean ketamine dose was 339.3mg in patients intubated versus 350.7mg in patients not (-11.4mg difference; 95% CI, -72.4 to 49.6). The mean weight-based ketamine dose was 4.44mg/kg in patients intubated versus 4.96mg/kg in patients not (-0.53mg/kg difference; 95% CI, -1.49 to 0.43).

The observed rate of intubation in patients receiving prehospital ketamine for agitation was 16.3%. Study data did not reveal an age or dose-dependent rate of intubation. Further research should be conducted to compare the airway intervention rate of agitated patients receiving ketamine versus other sedatives in a controlled fashion.

The utility and efficacy of bolus dose vasopressors in hemodynamically unstable patients is well-established in the fields of general anesthesia and obstetrics. However, in the prehospital setting, minimal evidence for bolus dose vasopressor use exists and is primarily limited to critical care transport use. Hypotensive episodes, whether traumatic, peri-intubation-related, or septic, increase patient mortality. The purpose of this study is to assess the efficacy and adverse events associated with prehospital bolus dose epinephrine use in non-cardiac arrest, hypotensive patients treated by a single, high-volume, ground-based Emergency Medical Services (EMS) agency.

This is a retrospective, observational study of all non-cardiac arrest EMS patients treated for hypotension using bolus dose epinephrine from September 12, 2018 through September 12, 2019. Inclusion criteria for treatment with bolus dose epinephrine required a systolic blood pressure (SBP) measurement <90mmHg. A dose of 20mcg every two minutes, as needed, was allowed per protocol. The primary data source was the EMS electronic medical record.

Forty-two patients were treated under the protocol with a median (IQR) initial SBP immediately prior to treatment of 78mmHg (65-86) and a median (IQR) initial mean arterial pressure (MAP) of 58mmHg (50-66). The post-bolus SBP and MAP increased to 93mmHg (75-111) and 69mmHg (59-83), respectively. The two most common patient presentations requiring protocol use were altered mental status (55%) and respiratory failure (31%). Over one-half of the patients treated required both advanced airway management (62%) and multiple bolus doses of vasopressor support (55%). A single episode of transient severe hypertension (SBP>180mmHg) occurred, but there were no episodes of unstable tachyarrhythmia or cardiac arrest while en route or upon arrival to the receiving hospitals.

These preliminary data suggest that the administration of bolus dose epinephrine may be effective at rapidly augmenting hypotension in the prehospital setting with a minimal incidence of adverse events. Paramedic use of bolus dose epinephrine successfully increased SBP and MAP without clinically significant side effects. Prospective studies with larger sample sizes are needed to further investigate the effects of prehospital bolus dose epinephrine on patient morbidity and mortality.

The American Heart Association (AHA; Dallas, Texas USA) and European Resuscitation Council (Niel, Belgium) cardiac arrest (CA) guidelines recommend the intraosseous (IO) route when intravenous (IV) access cannot be obtained. Vasopressin has been used as an alternative to epinephrine to treat ventricular fibrillation (VF).

Limited data exist on the pharmacokinetics and resuscitative effects of vasopressin administered by the humeral IO (HIO) route for treatment of VF. The purpose of this study was to evaluate the effects of HIO and IV vasopressin, on the occurrence, odds, and time of return of spontaneous circulation (ROSC) and pharmacokinetic measures in a swine model of VF.

Twenty-seven Yorkshire-cross swine (60 to 80 kg) were assigned randomly to three groups: HIO (n=9), IV (n=9), and a control group (n=9). Ventricular fibrillation was induced and untreated for two minutes. Chest compressions began at two minutes post-arrest and vasopressin (40 U) administered at four minutes post-arrest. Serial blood specimens were collected for four minutes, then the swine were resuscitated until ROSC or 29 post-arrest minutes elapsed.

Fisher’s Exact test determined ROSC was significantly higher in the HIO 5/7 (71.5%) and IV 8/11 (72.7%) groups compared to the control 0/9 (0.0%; P=.001). Odds ratios of ROSC indicated no significant difference between the treatment groups (P=.68) but significant differences between the HIO and control, and the IV and control groups (P=.03 and .01, respectively). Analysis of Variance (ANOVA) indicated the mean time to ROSC for HIO and IV was 621.20 seconds (SD=204.21 seconds) and 554.50 seconds (SD=213.96 seconds), respectively, with no significant difference between the groups (U=11; P=.22). Multivariate Analysis of Variance (MANOVA) revealed the maximum plasma concentration (Cmax) and time to maximum concentration (Tmax) of vasopressin in the HIO and IV groups was 71753.9 pg/mL (SD=26744.58 pg/mL) and 61853.7 pg/mL (SD=22745.04 pg/mL); 111.42 seconds (SD=51.3 seconds) and 114.55 seconds (SD=55.02 seconds), respectively. Repeated measures ANOVA indicated no significant difference in plasma vasopressin concentrations between the treatment groups over four minutes (P=.48).

The HIO route delivered vasopressin effectively in a swine model of VF. Occurrence, time, and odds of ROSC, as well as pharmacokinetic measurements of HIO vasopressin, were comparable to IV.

BurgertJM, JohnsonAD, Garcia-BlancoJ, FultonLV, LoughrenMJ. The Resuscitative and Pharmacokinetic Effects of Humeral Intraosseous Vasopressin in a Swine Model of Ventricular Fibrillation. Prehosp Disaster Med. 2017;32(3):305–310.

Vasopressors are associated with return of spontaneous circulation (ROSC), but no long-term benefit has been demonstrated in randomized trials. However, these trials did not control for the timing of vasopressor administration which may influence outcomes. Consequently, the objective of this study was to develop a model describing the likelihood of favorable neurological outcome (cerebral performance category [CPC] 1 or 2) as a function of the public safety answering point call receipt (PSAP)-to-pressor-interval (PPI) in prolonged out-of-hospital cardiac arrest.

The likelihood of favorable neurological outcome declines with increasing PPI.

This investigation was a retrospective study of cardiac arrest using linked data from the Cardiac Arrest Registry to Enhance Survival (CARES) database (Centers for Disease Control and Prevention [Atlanta, Georgia USA]; American Heart Association [Dallas, Texas USA]; and Emory University Department of Emergency Medicine [Atlanta, Georgia USA]) and the North Carolina (USA) Prehospital Medical Information System. Adult patients suffering a bystander-witnessed, non-traumatic cardiac arrest between January 2012 and June 2014 were included. Logistic regression was used to calculate the adjusted odds ratio (OR) of neurological outcome as a function of PPI, while controlling for patient age, gender, and race; endotracheal intubation (ETI); shockable rhythm; layperson cardiopulmonary resuscitation (CPR); and field hypothermia.

Of the 2,100 patients meeting inclusion criteria, 913 (43.5%) experienced ROSC, 618 (29.4%) survived to hospital admission, 187 (8.9%) survived to hospital discharge, and 155 (7.4%) were discharged with favorable neurological outcomes (CPC 1 or 2). Favorable neurological outcome was less likely with increasing PPI (OR=0.90; P<.01) and increasing age (OR=0.97; P<.01). Compared to patients with non-shockable rhythms, patients with shockable rhythms were more likely to have favorable neurological outcomes (OR=7.61; P<.01) as were patients receiving field hypothermia (OR=2.13; P<.01). Patient gender, non-Caucasian race, layperson CPR, and ETI were not independent predictors of favorable neurological outcome.

In this evaluation, time to vasopressor administration was significantly associated with favorable neurological outcome. Among adult, witnessed, non-traumatic arrests, the odds of hospital discharge with CPC 1 or 2 declined by 10% for every one-minute delay between PSAP call-receipt and vasopressor administration. These retrospective observations support the notion of a time-dependent function of vasopressor effectiveness on favorable neurological outcome. Large, prospective studies are needed to verify this relationship.

HubbleMW, TysonC. Impact of Early Vasopressor Administration on Neurological Outcomes after Prolonged Out-of-Hospital Cardiac Arrest. Prehosp Disaster Med. 2017; 32(3):297–304.

Obtaining intravenous (IV) access in patients in hemorrhagic shock is often difficult and prolonged. Failed IV attempts delay life-saving treatment. Intraosseous (IO) access may often be obtained faster than IV access. Albumin (5%) is an option for prehospital volume expansion because of the absence of interference with coagulation and platelet function.

There are limited data comparing the performance of IO and IV administered 5% albumin. The aims of this study were to compare the effects of tibial IO (TIO) and IV administration of 500 mL of 5% albumin on infusion time and hemodynamic measurements of heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), and stroke volume (SV) in a swine model of hemorrhagic shock.

Sixteen male swine were divided into two groups: TIO and IV. All subjects were anesthetized and a Class III hemorrhage was achieved by exsanguination of 31% of estimated blood volume (EBV) from a femoral artery catheter. Following exsanguination, 500 mL of 5% albumin was administered under pressurized infusion (300 mmHg) by the TIO or IV route and infusion time was recorded. Hemodynamic measurements of HR, MAP, CO, and SV were collected before and after exsanguination and every 20 seconds for 180 seconds during 5% albumin infusion.

An independent t-test determined that IV 5% albumin infusion was significantly faster compared to IO (P=.01). Mean infusion time for TIO was seven minutes 35 seconds (SD=two minutes 44 seconds) compared to four minutes 32 seconds (SD=one minute 08 seconds) in the IV group. Multivariate Analysis of Variance was performed on hemodynamic data collected during the 5% albumin infusion. Analyses indicated there were no significant differences between the TIO and IV groups relative to MAP, CO, HR, or SV (P>.05).

While significantly longer to infuse 5% albumin by the TIO route, the longer TIO infusion time may be negated as IO devices can be placed more quickly compared to repeated IV attempts. The lack of significant difference between the TIO and IV routes relative to hemodynamic measures indicate the TIO route is a viable route for the infusion of 5% albumin in a swine model of Class III hemorrhage.

MuirSL , SheppardLB , Maika-WilsonA , BurgertJM , Garcia-BlancoJ , JohnsonAD , CoynerJL . A Comparison of the Effects of Intraosseous and Intravenous 5% Albumin on Infusion Time and Hemodynamic Measures in a Swine Model of Hemorrhagic Shock. Prehosp Disaster Med.2016;31(4):436–442.

Although the majority of Australian intensive care paramedics use the manual intraosseous infusion technique (MAN-IO), several other semiautomatic devices now are available, such as the bone injection gun (BIG) and the semiautomatic intraosseous infusion system (EZ-IO). Given the choice of devices now available, questions have been raised regarding success rates, accuracy, decay of skills, and adverse events.

Review the literature regarding the use of intraosseous (IO) devices in the prehospital setting.

Selected electronic databases (Medline, Embase, and CINAHL) were searched, and a hand search was conducted for grey-literature that included studies from the commencement of the process to the end of May 2010. Inclusion criteria were any study reporting intraosseous insertion and/or infusion (adult and pediatric) by paramedics in the prehospital setting.

The search located 2,100 articles; 20 articles met the inclusion criteria. The review also noted that use of IO access (regardless of technique) offers a safe and simple method for gaining access to the patients’ vascular system. A number of studies found that the use of semiautomatic devices offers better and faster intraosseous access compared with the use of manual devices, and also were associated with fewer complications. The findings also suggest that the use of semiautomatic devices can reduce insertion times and the number of insertion attempts when contrasted with the use of manual insertion techniques. Despite these findings, statistically no specific IO device has proven clinical superiority.

While manual IO techniques currently are used by the majority of Australian paramedics, the currently available evidence suggests that semiautomatic devices are more effective. Further research, including cost-benefit analyses, is required at a national level to examine skill acquisition, adverse effects, and whether comparative devices offer clinically significant advantages.

OlaussenA , WilliamsB . Intraosseous Access in the Prehospital Setting: Literature Review. Prehosp Disaster Med.2012;27(5):1-5.

The First Access for Shock and Trauma (FAST 1) Sternal Intraosseous (IO) System is a vascular access device designed as an alternative to peripheral or central intravenous (IV) cannulation for the treatment of critically ill and injured adults. During the development of the device, key objectives included safety, speed of insertion, and ease of use with minimal training. This study evaluated these characteristics.

Ten experienced paramedics participated in a 90-minute training program for the use of the FAST 1 System at the Paramedic Academy of the Justice Institute of British Columbia. Then, the paramedics used thesystem in three simulated prehospital scenarios and evaluated the ease of use and compatibility of the training method with current practice using a 10-centimeter (cm) (3.94 inches (in)), visual analog scale.

The duration of the procedure from opening the package to initiation of fluid flow ranged 52–127 seconds (mean = 92 ±32 seconds). Placement accuracy was excellent, with a mean displacement of 2 mm (0.08 in) and 1 mm (0.04 in) in the vertical and horizontal planes, respectively. The paramedics rated the system highly in all areas. They considered the training “straight forward” and “comprehensive”. The possibility for interference between the IO system and cervical collars was reported, and several suggestions to remedy this and achieve other improvements were made.

Placement of the FAST 1 is fast, accurate, and easy to use. Paramedics had useful input concerning the design of the product.

To determine the frequency of use and the success rates of intraosseous (IO) vascular access in the emergency department.

A retrospective chart review.

A tertiary pediatric emergency department (ED) in a large urban centre.

ED resuscitations (ICD-9 code 996) occurring between Oct. 1, 1989, and Sept. 30, 1995, were identified by searching the ED database, inpatient database, ICU admission log and provincial medical examiner’s database. From these, all cases involving IO access were selected and comprised the study sample. Demographics, diagnosis, number of IO attempts, success or failure of IO placement, relevant times and patient outcomes were recorded on standard data forms. Frequency of use, success rates and performance times were reported.

IO access was successful in 36 of 42 (86%) patients. In total, there were 68 attempts, or 1.6 attempts per child. All but one child were less than 3 years of age. The median time to successful IO placement was 8 minutes. Two complications, both fractures, occurred in one patient, a 10-day-old neonate.

IO success rates were high despite infrequent use.