Intraosseous drug administration in children and adults during cardiopulmonary resuscitation

Evolution of the use of intraosseous vascular access in prehospital advanced cardiopulmonary resuscitation: The IOVA-CPR study

INTRODUCTION

Obtaining vascular access is crucial in critically ill patients. The EZ-IO® device is easy to use and has a high insertion success rate. Therefore, the use of intraosseous vascular access (IOVA) has gradually increased.

AIM

We aim to determine how IOVA was integrated into management of vascular access during out-of-hospital cardiac arrest (OHCA) resuscitation.

METHODS

Analysing the data from the OHCA French registry for events occurring between 1 January 2013 and 15 March 2021, we studied: demography, circumstances of occurrence and management including vascular access, delays and evolution. The primary outcome was the rate of IOVA implantation.

RESULTS

Among the 7156 OHCA included in the registry, we analysed the 3964 (55%) who received cardiopulmonary resuscitation. The vascular access was peripheral in 3122 (79%) cases, intraosseous in 775 (20%) cases and central in 12 (<1%) cases. The use of IOVA has increased linearly (R2 = 0.61) during the 33 successive trimesters studied representing 7% of all vascular access in 2013 and 33% in 2021 (p = 0.001). It was significantly more frequent in traumatic cardiac arrest: 12% versus 5%; p < 0.0001. The first epinephrine bolus occurred significantly later in the IOVA group, at 6 (4-10) versus 5 (3-8) min; p < 0.0001. Survival rate in the IOVA group was significantly lower, at 1% versus 7%; p < 0.0001.

CONCLUSION

The insertion rate of IOVA significantly increased over the studied period, to reach 30% of all vascular access in the management OHCA patients. The place of the intraosseous route in the strategy of venous access during the management of prehospital cardiac arrest has yet to be determined.

The Efficacy of Intraosseous Access for Initial Resuscitation in Patients with Severe Trauma: A Retrospective Multicenter Study in South Korea

Background/Objective: In patients with severe trauma, intraosseous (IO) access is an alternative when intravenous (IV) access proves challenging. However, detailed insights into its utilization patterns and effectiveness are lacking. This study aims to evaluate the use and efficacy of IO access in hemodynamically unstable patients with trauma at level-1 trauma centers in South Korea. Methods: Data from six centers over 12 months were analyzed, focusing on patients with traumatic cardiac arrest or shock. Overall, 206 patients were included in the study: 94 in the IO group and 112 in the IV group. Results: The first-attempt success rate was higher in the IO group than in the IV group (90.4% vs. 75.5%). The procedure time in the IO group was also shorter than that in the IV group. The fluid infusion rate was lower in the IO group than in the IV group; however, the use of a pressure bag with IO access significantly increased the rate, making it comparable to the IV infusion rate. Further, regarding IO access, a humeral site provided a higher infusion rate than a tibial site. Conclusions: IO access offers a viable alternative to IV access for the initial resuscitation in patients with trauma, providing advantages in terms of procedure time and first-attempt success rate. The use of a pressure bag and a humeral site for IO access afforded infusion rates comparable to those associated with IV access.

Wilderness Medical Society Clinical Practice Guidelines for the Treatment of Acute Pain in Austere Environments: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the "WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments" published in Wilderness & Environmental Medicine 2014; 25:41-49.

Intraosseous Regional Administration of Antibiotic Prophylaxis for Total Knee Arthroplasty: A Systematic Review

BACKGROUND

Intraosseous regional administration (IORA) of antibiotics after tourniquet inflation has recently been introduced as a technique to deliver antibiotics directly to the surgical site among patients undergoing total knee arthroplasty (TKA).

METHODS

PubMed and Embase were queried for studies reporting on IORA for perioperative prophylaxis during TKA. Primary outcome measures were local tissue antibiotic concentrations and rates of prosthetic joint infection (PJI). Eight studies were included for analysis. Four studies (all randomized controlled trials) compared local tissue concentrations between patients receiving IORA and intravenous (IV) antibiotics. Six studies assessed the rate of PJI among patients receiving IORA versus IV antibiotics.

RESULTS

All studies found a statistically significant increase in antibiotic concentration in femoral bone and fat samples in patients who were treated with IORA (44.04 μg/g [fat] and 49.3 μg/g [bone] following 500 mg of intraosseous vancomycin) versus IV (3.5 μg/g [fat] and 5.2 μg/g [bone] following 1 g IV of vancomycin). The two studies powered to determine differences in PJI rates found a statistically significant decrease in the rate of PJI among patients receiving IORA versus IV antibiotics. The incidence of PJI in patients treated with IORA and IV antibiotics across all studies was 0.3 and 1.1%, respectively.

CONCLUSION

Perioperative IORA of antibiotics in TKA provides local tissue concentrations of antibiotics that are on average 10 times higher than IV administration alone. Although more adequately powered investigations are necessary to determine the effectiveness of IORA in reducing PJI rates, adoption of IORA should be considered in high-risk patients where elevated tissue antibiotic concentrations would be of a maximum benefit.

Efficacy of intraosseous access for trauma resuscitation: a systematic review and meta-analysis

BACKGROUND

During medical emergencies, intraosseous (IO) access and intravenous (IV) access are methods of administering therapies and medications to patients. Treating patients in emergency medical situations is a highly time sensitive practice; however, research into the optimal access method is limited and existing systematic reviews have only considered out-of-hospital cardiac arrest (OHCA) patients. We focused on severe trauma patients and conducted a systematic review to evaluate the efficacy and efficiency of intraosseous (IO) access compared to intravenous (IV) access for trauma resuscitation in prehospital care.

MATERIALS AND METHOD

PubMed, Web of Science, Cochrane Library, EMBASE, ScienceDirect, banque de données en santé publique and CNKI databases were searched for articles published between January 1, 2000, and January 31, 2023. Adult trauma patients were included, regardless of race, nationality, and region. OHCA patients and other types of patients were excluded. The experimental and control groups received IO and IV access, respectively, in the pre-hospital and emergency departments for salvage. The primary outcome was success rate on first attempt, which was defined as secure needle position in the marrow cavity or a peripheral vein, with normal fluid flow. Secondary outcomes included mean time to resuscitation, mean procedure time, and complications.

RESULTS

Three reviewers independently screened the literature, extracted the data, and assessed the risk of bias in the included studies; meta-analyses were then performed using Review Manager (Version 5.4; Cochrane, Oxford, UK). The success rate on first attempt was significant higher for IO access than for IV access (RR = 1.46, 95% CI [1.16, 1.85], P = 0.001). The mean procedure time was significantly reduced (MD = - 5.67, 95% CI [- 9.26, - 2.07], P = 0.002). There was no significant difference in mean time to resuscitation (MD = - 1.00, 95% CI [- 3.18, 1.17], P = 0.37) and complications (RR = 1.22, 95% CI [0.14, 10.62], P = 0.86) between the IO and IV groups.

CONCLUSION

The success rate on first attempt of IO access was much higher than that of IV access for trauma patients, and the mean procedure time of IO access was significantly less when compared to IV access. Therefore, IO access should be suggested as an urgent vascular access for hypotensive trauma patients, especially those who are under severe shock.

Intraosseous Tibial Resuscitation After a Total Knee Arthroplasty Leading to Osteonecrosis and Loosening of the Tibial Component

A 51-year-old woman suffered cardiac arrest requiring emergent intraosseous access that abutted the tibial component of her total knee arthroplasty. She developed a wound at the site and knee pain which was concerning for deep infection. Subsequent imaging was consistent with osteonecrosis developing around the tibial component. The component eventually loosened, requiring a revision surgery. Her deep cultures remained negative throughout. Her findings are most consistent with osteonecrosis and aseptic loosening of her prosthesis. While intraosseous access may be beneficial during resuscitation, it has complications. This is the first reported case of osteonecrosis secondary to intraosseous access leading to prosthetic loosening necessitating a revision surgery.

Fat embolism after intraosseous catheters in pediatric forensic autopsies

In our center, we performed the autopsy of a child who died from drowning and presented, at autopsy, a major pulmonary fat embolism (PFE). A cardiopulmonary resuscitation (CPR) was performed, including infusion by intraosseous catheter (IIC). No other traumatic lesions and diseases classically related to a risk of PFE were detected. According to some animal studies, we considered the IIC as the only possible cause for PFE. However, we could not find literature to confirm this hypothesis in humans, especially in a pediatric population. To verify the occurrence of PFE after IIC in a pediatric population, we retrospectively selected 20 cases of pediatric deaths autopsied in our center, in which a CPR was performed, without bone fractures or other possible causes of PFE: 13 cases with IIC (group A) and 7 cases without IIC (group B). Several exclusion criteria were considered. The histology slides of the pulmonary tissue were stained by Oil Red O. PFE was classified according to the Falzi scoring system. In group A, 8 cases showed PFE: 4 cases with a score 1 of Falzi and 4 cases with a score 2 of Falzi. In group B, no case showed PFE. The difference between the two groups was statistically significant. The results of our study seem to confirm that IIC can lead to PFE in a pediatric population and show that the PFE after IIC can be important (up to score 2 of Falzi). To the best of our knowledge, our study is the first specifically focused on the occurrence of PFE after IIC in a pediatric population by using autoptic data.

Drug Delivery and Safety Considerations

Anesthetic drugs must be delivered at the appropriate dose and route of administration to produce the expected anesthetic effects. This is important for patient safety because anesthetic drugs function by depressing the central nervous and cardiovascular systems, which if improperly dosed or administered could cause potentially life-threatening effects. Several routes of administration and different drug delivery methods are available to safely and reliably anesthetize zoologic companion animal patients. Because of the nature of zoologic companion animal practice, anesthetic procedures pose risks that the anesthetist should understand to carefully plan procedures that are as safe and efficient as possible.

Single Versus Double Anatomic Site Intraosseous Blood Transfusion in a Swine Model of Hemorrhagic Shock

BACKGROUND

Blood transfusion via single site intraosseous access is a critical modality when caring for a trauma victim that lacks intravascular access. Flow rates and potential clinical complications when utilizing two sites of intraosseous access are not well known.

MATERIALS AND METHODS

Anesthetized adult female Yorkshire swine (Sus scrofa; n = 48; 76.7 ± 1.75kg; range 66-90kg) were cannulated and then bled approximately 30% total blood volume. Swine were randomly assigned to treatment groups: single sited humerus, single sited sternum, dual sited humerus or dual sited humerus and sternum. Flow rates, hemolysis, physiologic measurements, biochemical variables, and pulmonary histologic inflammation and occlusion were contrasted between groups.

RESULTS

Dual sited intraosseous transfusion flow rates (128ml/min, 95% CI 123-132) were double the flow rates of single sites (65ml/min, 95% CI 60-70), P < .0001.Single sited humeral flow rates were greater than sternal flow rates, with respective averages of 74ml/min and 55ml/min, though not reaching statistical significance (P < 0.17). There was no significant elevation of plasma free hemoglobin in any group after transfusion as compared to baseline (P = 0.7). Groups did not significantly differ in vitals or biochemical variables. Most pulmonary specimens had some intraparenchymal fat embolism, however no animals had evidence of occlusive intra-arterial fat embolism.

CONCLUSIONS

Dual anatomic site, pressure bag driven, intraosseous blood transfusion approximately doubles flow rates without evidence of clinical complications or hemolysis. Further research using a survivability model is needed to characterize long-term complications from pressurized IO transfusions.

The association of intraosseous vascular access and survival among pediatric patients with out-of-hospital cardiac arrest

INTRODUCTION

In pediatric out-of-hospital cardiac arrest (OHCA) the effect of intraosseous (IO) or intravenous (IV) access on outcomes is unclear.

METHODS

We analyzed prospectively collected data of non-traumatic OHCA in the Resuscitation Outcomes Consortium registry from 2011 to 2015. We included EMS-treated patients ≤17 years of age, classified patients based on vascular access routes, and calculated success rates of IO and IV attempts. After excluding patients with obvious non-cardiac etiologies and those with unsuccessful vascular access or multiple routes, we fit a logistic regression model to evaluate the association of IO vascular access (reference IV access) with the primary outcome of survival, using multiple imputation to address missing data. We analyzed a subgroup of patients at least 2 years of age.

RESULTS

There were 1549 non-traumatic OHCA: 895 (57.8%) patients had an IO line attempted with 822 (91.8%) successful; 488 (31.5%) had an IV line attempted with 345 (70.7%) successful (difference 21%, 95% CI 17 to 26%). Of the 761 patients included in our logistic regression, 601 received IO (30 [5.2%] survived) and 160 received IV (40 [25%] survived) vascular access. Intraosseous access was associated with a decreased probability of survival (adjusted OR 0.46; 95% CI 0.21-0.98). Patients at least 2 years of age showed a similar association (adjusted OR 0.36; CI 0.15-0.86).

CONCLUSIONS

Intraosseous access was associated with decreased survival among pediatric non-traumatic OHCA. These results are exploratory and support the need for further study to evaluate the effect of intravascular access method on outcomes.

Complications of Intraosseous Access: Two Case Reports From a Single Center

CASES

Intraosseous (IO) access is an effective surrogate for intravascular access in critically ill patients. We present 2 cases of IO complications. The first patient is a 44-year-old man with deep peroneal nerve sensorimotor dysfunction due to possible missed acute compartment syndrome from improper placement of a tibial IO needle. The second patient is an immunosuppressed 69-year-old man with idiopathic factor VIII deficiency who required amputation 7 months after right tibia IO access.

CONCLUSION

These adverse events of IO access are limited in the literature. We make recommendations to reduce these outcomes.

Validation of intraosseous delivery of valproic acid in a swine model of polytrauma

Background

Intraosseous (IO) drug delivery may be necessary in emergency situations when intravenous access is unattainable. Valproic acid (VPA) is a histone deacetylase inhibitor that has previously been shown to improve survival in preclinical models of lethal polytrauma. In this study, we sought to compare serum levels of intravenously and IO-delivered VPA, and to analyze the effect of IO-delivered VPA.

Methods

Swine were subjected to 40% blood volume hemorrhage, brain injury, femur fracture, rectus crush injury and liver laceration. After 1 hour of shock, animals were randomized (n=3/group) to receive normal saline resuscitation (control), normal saline+intravenous VPA 150 mg/kg (intravenous group) or normal saline +IO VPA 150 mg/kg (IO group). Serum levels of VPA were assessed between groups, and proteomics analyses were performed on IO and control groups on heart, lung and liver samples.

Results

Intravenous and IO serum VPA levels were similar at 1, 3, 5 and 7 hours after starting the infusion (p>0.05). IO-delivered VPA induced significant proteomics changes in the heart, lung and liver, which were most pronounced in the lung. Biologic processes affected included inflammation, metabolism and transcriptional & translational machinery. The control group had 0% survival, and the intravenous and IO group both had 100% survival to the end of the experiment (p<0.05).

Discussion

IO-delivered VPA is noninferior to intravenous administration and is a viable option in emergent situations when intravenous access is unattainable.

Level of evidence

Not applicable (animal study).

Intraosseous or Peripheral IV Access in Pediatric Cardiac Arrest? Results From the French National Cardiac Arrest Registry

OBJECTIVES

Despite the evolving recommendations that favor the use of intraosseous access in pediatric resuscitation, the impact of vascular access type on survival in young children has not been demonstrated. The aim of this study was to assess the impact of the intravascular injection route on the return on spontaneous circulation, survival to hospital admission (0 day), and 30 days or survival to hospital discharge, by comparing survival rates in young children having intraosseous and peripheral IV access. The second aim was to compare the rates of favorable neurologic outcome after 30 days or survival to hospital discharge.

DESIGN

This was a multicenter retrospective comparative study between July 2011 and October 2018.

SETTING

Based on the French cardiac arrest registry data.

PATIENTS

All prepubescent (males < 12 yr old, females < 10 yr old) victims of an out-of-hospital cardiac arrest.

INTERVENTIONS

Patients with adrenaline administration by intraosseous versus peripheral venous technique were compared, using propensity score matching.

MEASUREMENTS AND MAIN RESULTS

The analysis included 603 prepubescent patients, 351 (58%) in the intraosseous group and 252 (42%) in the peripheral IV group. Intraosseous group patients were younger, lighter, with more medical cause for arrest. The intraosseous group had lower survival rates at 30 days or hospital discharge (n = 6; 1.7%) than the peripheral IV group (n = 12; 4.8%) (p = 0.030). After matching, 101 pairs of patients were created. No difference was observed on return of spontaneous circulation or 0-day survival rates (odds ratio = 1.000 [95% CI, 0.518-1.930]; odds ratio = 0.946 [95% CI, 0.492-1.817], respectively) and on 30 days or hospital discharge survival (n = 3 in both groups) (odds ratio = 1.000 [95% CI, 0.197-5.076]). Meaningful statistical evaluation of neurologic status among survivors was precluded by inadequate numbers.

CONCLUSIONS

The type of injection route (intraosseous or peripheral venous access) does not appear to have an impact on survival of out-of-hospital cardiac arrest in a prepubescent population, but limitations of propensity matching limit a definitive conclusion.

Intraosseous Administration of Hypertonic Saline in Acute Brain-Injured Patients: A Prospective Case Series and Literature Review

BACKGROUND

Central venous catheters are often used to administer hypertonic saline (HTS) but might be associated with serious complications. Intraosseous (IO) access is an alternative method of medication and fluid delivery which is not associated with life-threatening complications and can be inserted faster than CVCs.

METHODS

A prospective case series was conducted on critically ill neurological patients that did not have central venous access, and for whom 3% HTS was indicated. Nonverbal indicators of pain were measured using the critical care pain observation tool. The pain score and serum sodium levels were collected at baseline, at 2, 6, 12, 18, and 24 hours after administration of 3% HTS using IO access. The area surrounding the IO insertion site was monitored for needle placement, extravasation, and tissue damage.

RESULTS

Five patients were enrolled. Three had an IO placed in the proximal humerus and 2 in the proximal tibia. Most patients did not have nonverbal indicators of pain during insertion and initial bolus. Serum sodium levels increased appropriately, as determined by the care providers. There were no cases of device dislodgement, extravasation, infection, soft tissue injury, or other local complications.

CONCLUSIONS

In this prospective case series, IO administration of 3% HTS was feasible, well-tolerated on the basis of nonverbal indicators of pain in the majority of patients and resulted in an appropriate rise in serum sodium levels. IO fills a niche among vascular access options for HTS, in emergent neurological situations when central venous access is not readily available or peripheral intravenous access is difficult to obtain.

Point-of-care analyses of blood samples from intraosseous access in pre-hospital critical care

BACKGROUND

Intraosseous (IO) access is used for fluid and medication administration in emergency situations when difficulties with vascular access are encountered. IO access would be readily available to take samples for point-of-care (POC) analysis, but there is scarce evidence about the reliability of POC analysis of IO samples among emergency patients. The aim of this study was to evaluate the feasibility and reliability of POC analysis of IO samples in critically ill pre-hospital patients.

METHODS

We performed a prospective, observational study in 35 critically ill pre-hospital patients. After inserting a humeral IO needle, we immediately drew an IO sample. We compared the results to an arterial sample drawn from the same patient within 5 (blood gases) or 15 (other parameters) minutes. Samples were analysed with an i-STAT® POC analyser for blood gases, acid-base balance, electrolytes, glucose and haemoglobin. The agreement between each patient's IO and arterial samples was analysed using the Bland-Altman method. The results were compared to responses about acceptable bias on a questionnaire sent to 16 experienced emergency physicians.

RESULTS

The analysis was successful for 23 patients (70%). Higher age was associated with failed analyses. The average bias was acceptable for base excess, pH, standard bicarbonate, glucose, ionized calcium and sodium. IO potassium values were systematically higher than arterial values. IO haemoglobin values had widely varying agreement.

CONCLUSION

When vascular access is challenging, IO access can be used for emergency POC analyses to help guide clinical decision-making. However, the limitations of IO POC analyses must be carefully considered.

Prevention, Treatment, and Monitoring of Seizures in the Intensive Care Unit

The diagnosis and management of seizures in the critically ill patient can sometimes present a unique challenge for practitioners due to lack of exposure and complex patient comorbidities. The reported incidence varies between 8% and 34% of critically ill patients, with many patients often showing no overt clinical signs of seizures. Outcomes in patients with unidentified seizure activity tend to be poor, and mortality significantly increases in those who have seizure activity longer than 30 min. Prompt diagnosis and provision of medical therapy are crucial in order to attain successful seizure termination and prevent poor outcomes. In this article, we review the epidemiology and pathophysiology of seizures in the critically ill, various seizure monitoring modalities, and recommended medical therapy.

Clinical Survey and Predictors of Outcomes of Pediatric Out-of-Hospital Cardiac Arrest Admitted to the Emergency Department

Pediatric out-of-hospital cardiac arrest (OHCA) is a rare event with severe sequelae. Although the survival to hospital-discharge (STHD) rate has improved from 2–6% to 17.6–40.2%, only 1–4% of OHCA survivors have a good neurological outcome. This study investigated the characteristics of case management before and after admittance to the emergency department (ED) associated with outcomes of pediatric OHCA in an ED. This was a retrospective study of data collected from our ED resuscitation room logbooks dating from 2005 to 2016. All records of children under 18 years old with OHCA were reviewed. Outcomes of interest included sustained return of spontaneous circulation (SROSC), STHD, and neurological outcomes. From the 12-year study period, 152 patients were included. Pediatric OHCA commonly affects males (55.3%, n = 84) and infants younger than 1 year of age (47.4%, n = 72) at home (76.3%, n = 116). Most triggers of pediatric OHCA were respiratory in nature (53.2%, n = 81). Sudden infant death syndrome (SIDS) (29.6%, n = 45), unknown medical causes (25%, n = 38), and trauma (10.5%, n = 16) were the main causes of pediatric OHCA. Sixty-two initial cardiac rhythms at the scene were obtained, most of which were asystole and pulseless electrical activity (PEA) (93.5%, n/all: 58/62). Upon ED arrival, cardiopulmonary resuscitation (CPR) was continued for 32.66 ± 20.71 min in the ED and 34.9% (n = 53) gained SROSC. Among them, 13.8% (n = 21) achieved STHD and 4.6% (n = 7) had a favorable neurological outcome. In multivariate analyses, fewer ED epinephrine doses (p < 0.05), witness of OHCA (p = 0.001), and shorter ED CPR duration (p = 0.007) were factors that increased the rate of SROSC at the ED. A longer emergency medical service (EMS) scene interval (p = 0.047) and shorter ED CPR interval (p = 0.047) improved STHD.

Acute Tibial osteomyelitis caused by intraosseous access during initial resuscitation: a case report and literature review

BACKGROUND

Intra-osseous (IO) access is recommended in cases of pre-hospital emergency or resuscitation when intravascular (IV) route is difficult or impossible. Despite recent improvement in IO devices and increasing indications, it remains rarely used in practice. Various complications have been reported but are uncommon.

CASE PRESENTATION

We report a case of massive acute tibial osteomyelitis in an adult male three months after an IO catheter insertion for emergency drug infusion. We review the literature on association between IO access and acute osteomyelitis in children and adults.

CONCLUSIONS

Emergency-care givers and radiologists should be informed about this infrequent complication in order to make early diagnosis and initiate adequate antibiotic therapy.

Intraosseous pressure during loading and with vascular occlusion in an animal model

Objectives

We studied subchondral intraosseous pressure (IOP) in an animal model during loading, and with vascular occlusion. We explored bone compartmentalization by saline injection.

Materials and Methods

Needles were placed in the femoral condyle and proximal tibia of five anaesthetized rabbits and connected to pressure recorders. The limb was loaded with and without proximal vascular occlusion. An additional subject had simultaneous triple recordings at the femoral head, femoral condyle and proximal tibia. In a further subject, saline injections at three sites were carried out in turn.

Results

Loading alone caused a rise in subchondral IOP from 11.7 mmHg (sd 7.1) to 17.9 mmHg (sd 8.1; p < 0.0002). During arterial occlusion, IOP fell to 5.3 mmHg (sd 4.1), then with loading there was a small rise to 7.6 mmHg (sd 4.5; p < 0.002). During venous occlusion, IOP rose to 20.2 mmHg (sd 5.8), and with loading there was a further rise to 26.3 mmHg (sd 6.3; p < 0.003). The effects were present at three different sites along the limb simultaneously. Saline injections showed pressure transmitted throughout the length of the femur but not across the knee joint.

Conclusion

This is the first study to report changes in IOP in vivo during loading and with combinations of vascular occlusion and loading. Intraosseous pressure is not a constant. It is reduced during proximal arterial occlusion and increased with proximal venous occlusion. Whatever the perfusion state, in vivo load is transferred partly by hydraulic pressure. We propose that joints act as hydraulic pressure barriers. An understanding of subchondral physiology may be important in understanding osteoarthritis and other bone diseases.

Cite this article: M. Beverly, S. Mellon, J. A. Kennedy, D. W. Murray. Intraosseous pressure during loading and with vascular occlusion in an animal model. Bone Joint Res 2018;7:511–516. DOI: 10.1302/2046-3758.78.BJR-2017-0343.R2.

Comparison of right and left ventricular enhancement times using a microbubble contrast agent between proximal humeral intraosseous access and brachial intravenous access during cardiopulmonary resuscitation in adults

AIM

The present study aimed to compare the ventricular enhancement time between humeral intraosseous access (HIO) and brachial intravenous access (BIV) during cardiopulmonary resuscitation (CPR) in adult humans. To our knowledge, this is the first such study during CPR in adult humans.

METHODS

This prospective single-centre observational cohort study assessed the medical records of patients who underwent CPR between January 2018 and March 2018. The primary endpoints were the left and right ventricular enhancement (LVE and RVE, respectively) times after administration of a microbubble contrast agent via HIO or BIV. Continuous variables are reported as means and standard deviations depending on normal distribution, while categorical variables are reported as frequencies and percentages. The paired t-test and analysis of variance were used to compare HIO and BIV. Differences were considered significant at a P-value <0.05.

RESULTS

The study included 10 patients. The HIO time (15.60 ± 6.45 s) was significantly lower than the BIV time (20.80 ± 7.05 s; P = 0.009). The RVE time was significantly lower with HIO (5.60 ± 1.71 s) than with BIV (15.40 ± 3.24 s; P < 0.001). Additionally, the LVE time was significantly lower with HIO (120.20 ± 4.18 s) than with BIV (132.00 ± 3.09 s; P < 0.001).

CONCLUSION

Our results indicated that the arrival times of a drug at the right and left ventricles are significantly lower with HIO than with BIV in an adult cardiac arrest model.

Tibial Osteomyelitis Following Prehospital Intraosseous Access

Intraosseous (IO) access is a lifesaving alternative to peripheral or central venous access in emergency care. However, emergency physicians and prehospital care providers must be aware of the potential for infectious complications associated with this intervention. We describe the case of a HIV-negative, otherwise immunocompetent adult patient who underwent prehospital insertion of a tibial IO device. Following successful resuscitation, the patient developed tibial osteomyelitis requiring multiple operative debridements, soft tissue coverage, and several courses of prolonged antimicrobial therapy. Skin antisepsis prior to device insertion followed by early device removal are important strategies for reducing the risk of infection associated with IO access.

Sternal Route More Effective than Tibial Route for Intraosseous Amiodarone Administration in a Swine Model of Ventricular Fibrillation

OBJECTIVE

The pharmacokinetics of IO administered lipid soluble amiodarone during ventricular fibrillation (VF) with ongoing CPR are unknown. This study measured mean plasma concentration over 5 minutes, maximum plasma concentration (Cmax), and time to maximum concentration (Tmax) of amiodarone administered by the sternal IO (SIO), tibial IO (TIO), and IV routes in a swine model of VF with ongoing CPR.

METHODS

Twenty-one Yorkshire-cross swine were randomly assigned to three groups: SIO, TIO, and IV. Ventricular fibrillation was induced under general anesthesia. After 4 minutes in VF, 300 mg amiodarone was administered as indicated by group assignment. Serial blood specimens collected at 30, 60, 90, 120, 150, 180, 240, and 300 seconds were analyzed using high performance liquid chromatography with tandem mass spectrometry.

RESULTS

The mean plasma concentration of IV amiodarone over 5 minutes was significantly higher than the TIO group at 60 seconds (P = 0.02) and 90 seconds (P = 0.017) post-injection. No significant differences in Cmax between the groups were found (P <0.05). The Tmax of amiodarone was significantly shorter in the SIO (99 secs) and IV (86 secs) groups compared to the TIO group (215 secs); P = 0.002 and P = 0.002, respectively.

CONCLUSIONS

The SIO and IV routes of amiodarone administration were comparable. The TIO group took nearly three times longer to reach Tmax than the SIO and IV groups, likely indicating depot of lipid-soluble amiodarone in adipose-rich tibial yellow bone marrow. The SIO route was more effective than the TIO route for amiodarone delivery in a swine model of VF with ongoing CPR. Further investigations are necessary to determine if the kinetic differences found between the SIO and TIO routes in this study affect survival of VF in humans.

Intraosseous compared to intravenous drug resuscitation in out-of-hospital cardiac arrest

AIMS

Although the intraosseous (IO) route is increasingly used for vascular access in out-of-hospital cardiac arrest (OHCA), little is known about its comparative effectiveness relative to intravenous (IV) access. We evaluated clinical outcomes following OHCA comparing drug administration via IO versus IV routes.

METHODS

This retrospective cohort study evaluated Emergency Medical Services (EMS)-treated adults with atraumatic OHCA in a large metropolitan EMS system between 9/1/2012-12/31/2014. Access was classified as IO or IV based on the route of first EMS drug administration. Study endpoints were survival to hospital discharge, return of spontaneous circulation (ROSC) and survival to hospital admission.

RESULTS

Among 2164 adults with OHCA, 1800 met eligibility criteria, 1525 of whom were treated via IV and 275 principally via tibial-IO routes. Compared to IV, IO-treated patients were younger, more often women, had unwitnessed OHCA, a non-cardiac aetiology, and presented with non-shockable rhythms. IO versus IV-treated patients were less likely to survive to hospital discharge (14.9% vs 22.8%, p=0.003), achieve ROSC (43.6% vs 55.5%, p<0.001) or be hospitalized (38.5% vs 50.0% p<0.001). In multivariable adjusted analyses, IO treatment was not associated with survival to discharge (odds ratio (OR) (95% confidence interval) 0.81 (0.55, 1.21), p=0.31), but was associated with a lower likelihood of ROSC (OR=0.67 (0.50, 0.88), p=0.004) and survival to hospitalization (OR=0.68 (0.51, 0.91), p=0.009).

CONCLUSION

Though not independently associated with survival to discharge, principally tibial IO versus IV treatment was associated with a lower likelihood of ROSC and hospitalization. How routes of vascular access influence clinical outcomes after OHCA merits additional study.

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016

OBJECTIVE

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012."

DESIGN

A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.

RESULTS

The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.

CONCLUSIONS

Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

Feasibility study of a novel intraosseous device in adult human cadavers

Background & objectives:

Intraosseous (IO) access is an alternative to difficult intravenous (iv) access during emergency clinical situations. Existing IO solutions are expensive, require power supply and trained manpower; limiting their use in resource constrained settings. To address these limitations, a novel IO device has been developed. The objectives of this study were to evaluate functionality and safety of this device in adult human cadavers.

Methods:

The ability of the IO device to penetrate the proximal and/or distal tibia was evaluated in three adult cadavers. Subjective parameters of loss of resistance, stable needle hold, easy needle withdrawal and any damage to the device were evaluated during the study. The insertion time was the objective parameter measured. Four sets of radiographs per insertion confirmed the position of the needle and identified complications.

Results:

A single physician performed 12 IO access procedures using the same device. Penetration of proximal and/or distal tibia was achieved in all instances. It was successful in the first attempt in eight (66.7%) and during second attempt in the remaining. The mean time to insertion was 4.1 ± 3.1 sec. Appropriate insertion of needle in the intra-medullary space of bone was confirmed with radiological examination in 10 (83.3%) insertions. In two occasions after penetrating the cortical layer of bone, the device overshot the intra-medullary space, as detected by radiological examination. Device got bent during insertion in one instance. There was no evidence of needle breakage or bone fracture. The needle could be withdrawn effortlessly in all instances.

Interpretation & conclusions:

The novel IO device could successfully penetrate the adult cadaver bones in most cases. Further studies are needed to confirm these results on a large sample.

Improving CPR Performance

Cardiac arrest continues to represent a public health burden with most patients having dismal outcomes. CPR is a complex set of interventions requiring leadership, coordination, and best practices. Despite the widespread adoption of new evidence in various guidelines, the provision of CPR remains variable with poor adherence to published recommendations. Key steps health-care systems can take to enhance the quality of CPR and, potentially, to improve outcomes, include optimizing chest compressions, avoiding hyperventilation, encouraging intraosseous access, and monitoring capnography. Feedback devices provide instantaneous guidance to the rescuer, improve rescuer technique, and could impact patient outcomes. New technologies promise to improve the resuscitation process: mechanical devices standardize chest compressions, capnography guides resuscitation efforts and signals the return of spontaneous circulation, and intraosseous devices minimize interruptions to gain vascular access. This review aims at identifying a discreet group of interventions that health-care systems can use to raise their standard of cardiac resuscitation.

Effect of Canal Anastomosis on Periapical Fluid Pressure Build-up during Needle Irrigation in Single Roots with Double Canals using a Polycarbonate Model

Sodium hypochlorite is an effective irrigant for chemical debridement of root canals. However, increasing the intracanal pressure during irrigant delivery may result in irrigant extrusion into the bone and soft tissues surrounding the tooth. Because clinicians often encounter teeth with intracanal communications, the objective of the present study was to examine the effects of canal anastomosis on the generation of periapical fluid pressure at different fluid flow rates and insertion depths. Two similar polycarbonate models were used to simulate a single root with double canals, one containing, and the other without communicating channels between the canals. For both models, periapical pressure increased with increasing irrigant flow rates and insertion depths of a 30-gauge side-venting needle. In the presence of communicating channels, the magnitude of pressure build-up decreased by almost 90% irrespective of the fluid flow rate or needle insertion depth. Pressure reduction in anastomoses-containing roots provides an explanation why pressure generation in single roots is considerably higher. Nevertheless, it is still possible in teeth with canal anastomoses for pressure exceeding the intraosseous pressure to be generated when the fluid flow rate is sufficiently high and when the needle tip is close to the apical terminus.

Blueprint for Implementing New Processes in Acute Care: Rescuing Adult Patients With Intraosseous Access

The intraosseous (IO) access initiative at an urban university adult level 1 trauma center began from the need for a more expeditious vascular access route to rescue patients in extremis. The goal of this project was a multidisciplinary approach to problem solving to increase access of IO catheters to rescue patients in all care areas. The initiative became a collaborative effort between nursing, physicians, and pharmacy to embark on an acute care endeavor to standardize IO access. This is a descriptive analysis of processes to effectively develop collaborative strategies to navigate hospital systems and successfully implement multilayered initiatives. Administration should empower nurse to advance their practice to include IO for patient rescue. Intraosseous access may expedite resuscitative efforts in patients in extremis who lack venous access or where additional venous access is required for life-saving therapies. Limiting IO dwell time may facilitate timely definitive venous access. Continued education and training by offering IO skill laboratory refreshers and annual e-learning didactic is optimal for maintaining proficiency and knowledge. More research opportunities exist to determine medication safety and efficacy in adult patients in the acute care setting.

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016

OBJECTIVE

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012".

DESIGN

A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.

RESULTS

The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.

CONCLUSIONS

Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

Intraosseous Injection of Simvastatin in Poloxamer 407 Hydrogel Improves Pedicle-Screw Fixation in Ovariectomized Minipigs

BACKGROUND

Osteoporosis leads to poor osseointegration and reduces implant stability. Statins have been found to stimulate bone formation, but the bioavailability from oral administration is low. Local application may be more effective at augmenting bone formation and enhancing implant stability. This study was performed to evaluate the efficacy of an intraosseous injection of simvastatin in thermosensitive poloxamer 407 hydrogel to enhance pedicle-screw fixation in calcium-restricted ovariectomized minipigs.

METHODS

Nine mature female Guangxi Bama minipigs underwent bilateral ovariectomy and were fed a calcium-restricted diet for 18 months. Simvastatin (0, 0.5, or 1 mg) in thermosensitive poloxamer 407 hydrogel was injected into the lumbar vertebrae (L4-L6), and titanium alloy pedicle screws were implanted. Bone mineral density (BMD) measurements of the lumbar vertebrae were determined by dual x-ray absorptiometry (DXA) before and 3 months after treatment. The lumbar vertebrae were harvested and analyzed with use of microcomputed tomography, biomechanical pull-out testing, histological analysis, and Western blot analysis for bone morphogenetic protein (BMP)-2 and vascular endothelial growth factor (VEGF) expression.

RESULTS

Evaluation over a 3-month study period demonstrated that the BMD of the vertebrae injected with 0.5 and 1.0 mg of simvastatin had increased by 31.25% and 31.09%, respectively, compared with vehicle-only injection (p ≤ 0.00014 for both) and increased by 32.12% and 28.16%, respectively, compared with the pre-treatment levels (p < 0.0001 for both). A single injection of simvastatin in poloxamer 407 increased trabecular volume fraction, thickness, and number and decreased trabecular separation (p ≤ 0.002). The bone formation and mineral apposition rates significantly increased (p ≤ 0.023). The percentage of osseointegration in the simvastatin 0.5 and 1-mg groups was 46.54% and 42.63% greater, respectively, than that in the vehicle-only group (p ≤ 0.006), and the maximum pull-out strength was 45.75% and 51.53% greater, respectively, than in the vehicle-only group (p ≤ 0.0005). BMP-2 and VEGF expressions were higher than for the vehicle-only injection.

CONCLUSIONS

A single intraosseous injection of simvastatin in thermosensitive poloxamer 407 hydrogel stimulated bone formation, increased BMD, improved bone microstructure, promoted osseointegration, and significantly enhanced the stability of pedicle screws in calcium-restricted ovariectomized minipigs.

CLINICAL RELEVANCE

These results provide rationale for evaluating intraosseous injection of simvastatin in poloxamer 407 to enhance implant fixation in patients with osteoporosis.

Comparison of tranexamic acid plasma concentrations when administered via intraosseous and intravenous routes

INTRODUCTION

There is a lack of information regarding intraosseous (IO) administration of tranexamic acid (TXA). Our hypothesis was that a single bolus IO injection of TXA will have a similar pharmacokinetic profile to TXA administered at the same dose IV.

METHODS

Sixteen male Landrace cross swine (mean body weight 27.6±2.6kg) were divided into an IV group (n=8) and an IO group (n=8). Each animal received 30mg/kg TXA via an IV or IO catheter, respectively. Jugular blood samples were collected for pharmacokinetic analysis over a 3h period. The maximum TXA plasma concentration (C_max) and corresponding time as well as distribution half-life, elimination half-life, area under the curve, plasma clearance and volume of distribution were calculated. One- and two-way analysis of variance for repeated measures (time, group) with Tukey's and Bonferonni post hoc tests were used to compare TXA plasma concentrations within and between groups, respectively.

RESULTS

Plasma concentrations of TXA were significantly higher (p<0.0001) in the IV group during the TXA infusion. C_max occurred at 4min after initiation of the bolus in the IV group (9.36±3.20ng/μl) and at 5min after initiation of the bolus in the IO group (4.46±0.49ng/μl). Plasma concentrations were very similar from the completion of injection onwards. There were no significant differences between the two administration routes for any other pharmacokinetic variables measured.

CONCLUSION

The results of this study support pharmacokinetic bioequivalence of IO and IV administration of TXA.

Double-barrelled resuscitation: A feasibility and simulation study of dual-intraosseous needles into a single humerus

INTRODUCTION

Resuscitation can be delayed, or impaired, by insufficient vascular access. This study examines whether dual-intraosseous needles, inserted into a single porcine humerus, can facilitate rapid and concomitant fluid and medication delivery.

METHODS

After inserting one- and then two-intraosseous needles into the same porcine humerus, we determined the rate of fluid administration using (i) an infusion pump set to 999mL/h, and (ii) a standard pressure-bag set to 300mmHg. Next, we concomitantly infused blood, crystalloid and medications into the same medullary canal, using the two-needle set-up. Humeri were inspected for fluid-leakage, needle-displacement, and bone damage.

RESULTS

Using an infusion pump, the mean normal-saline infusion-rate was significantly higher with dual-intraosseous needles compared to a single-intraosseous needle: the infusion-rate was 16mL/min using dual-needles versus 8mL/min for a single needle set-up (p<0.001). In contrast, using the pneumatic pressure-bag, the infusion rate was not statistically different when comparing dual-intraosseous needles versus single-intraosseous: the infusion-rate was 22mL/min versus 21ml/min (p=0.4) for 500mL, and 22ml/min versus 21ml/min (p=0.64) for one-litre, respectively. Blood product could be infused at a mean rate of 20mL/min through one needle while tranexamic acid was simultaneously infused through a second. There were no complications with a dual-intraosseous set-up (no fluid leakage; no needle-displacement; no high-pressure alarms, and no external bone-fractures or internal macrohistological damage) during any of our simulated resuscitation scenarios.

CONCLUSIONS

This is the first published study evaluating dual-intraosseous needles in a single bone. Despite limitations, this preliminary study (using a porcine humerus) suggests that dual-intraosseous needles are feasible. For critically-ill patients with limited insertion sites, dual-intraosseous (a.k.a. 'double-barrelled resuscitation') may facilitate rapid and concurrent resuscitation.

Guidelines for care of the newborn baby at birth knowledge by prehospital emergency physicians

INTRODUCTION

In 2010, the International Liaison Committee On Resuscitation (ILCOR) guidelines for care of the newborn baby immediately after birth were published.

MATERIALS AND METHODS

Using a questionnaire that was distributed to a sample of 44 prehospital emergency physicians (April 2014), we assessed knowledge of these guidelines, in particular specificities for newborns as compared to adults. Twenty-five questions, starting with a birth with no problems to one resulting in neonatal distress, were used to profile the practice of the surveyed physicians.

RESULTS

Among the solicited physicians, 30 responded to the questionnaire (68%). Priority was given to efficient respiratory resuscitation during the first minutes of extrauterine life and the difficulties of newborn respiratory adaptation are well-known, but their implementation remains imperfectly understood. The assessment showed very mixed results, partly explained by the low frequency of newborn scenarios experienced by the practitioners who responded to the questionnaire.

CONCLUSION

To move from guidelines to their practical implementation is always delicate, with room for improvement such as continuing education, knowledge assessment and practice in the context of a quality approach. Well accepted, this evaluation process could be renewed upon publication of the next guidelines on this subject, thus contributing to their knowledge.

Wilderness Medical Society practice guidelines for the treatment of acute pain in remote environments: 2014 update

The Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded on the basis of the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an updated version of the original WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments published in Wilderness & Environmental Medicine 2014;25(1):41-49.

Intraosseous and intravenous administration of antibiotics yields comparable plasma concentrations during experimental septic shock

BACKGROUND

We aimed to investigate whether comparable antibiotic concentrations could be reached with intraosseous and intravenous administration during septic shock.

METHODS

In this randomized, prospective experimental study conducted at an animal research laboratory at the University Hospital of Uppsala, eight anesthetized pigs, weighing 21.2 to 29.1 kg (mean: 25.2 ± 2.3 kg), received endotoxin infusion at 4 μg/kg/h for 6 h. At the onset of clinical shock, alternatively after 3 h of endotoxemia, they received 75 mg/kg of cefotaxime and 7 mg/kg of gentamicin either in a proximal tibial intraosseous catheter or in a peripheral intravenous catheter. Mixed venous samples were taken after 5, 15, 30, 60, 120 and 180 min and analyzed for antibiotic concentrations.

RESULTS

For both antibiotics, plasma concentrations after intraosseous and intravenous administration followed similar curves throughout the observation period, and peak concentrations were comparable. Mean concentration area under the curve (AUC mg × h/l) for cefotaxime was 108.1 ± 19.5 after intraosseous and 116.5 ± 11.1 after intravenous administration; ratio 0.93, (95% CI 0.71-1.19). Mean AUC for gentamicin was 28.1 ± 6.8 for intraosseous and 32.2 ± 3.5 for intravenous administration; ratio 0.87 (95% CI 0.62-1.19).

CONCLUSIONS

In this porcine septic shock model, intraosseous and intravenous administration of gentamicin and cefotaxime yielded comparable concentrations. In an emergency, intraosseous administration of these antibiotics may be considered in severe infections when venous access is difficult.

Fat Intravasation from Intraosseous Flush and Infusion Procedures

STUDY HYPOTHESIS

The primary study objective was to delineate the procedural aspects of intraosseous (IO) infusions responsible for fat intravasation by testing the hypothesis that the fat content of effluent blood increases during IO infusions.

METHODS

IO cannulas were inserted into the proximal tibiae of 35 anesthetized swine (Sus scrofa, 50.1 ± 3.5 kg) and intravasated fat was assessed using a lipophilic fluoroprobe (Nile red) and by vascular ultrasound imaging. Effluent blood bone marrow fat was assessed at baseline, during flush, and with regimens of controlled infusion pressures (73-300 mmHg) and infusion flow rates (0.3-3.0 mL per second). Fat intravasation was also assessed with IO infusions at different tibial cannulation sites and in the distal femur. In 7 animals, the lipid uptake of alveolar macrophages and lung tissue assessed for fat embolic burden using oil red O stain 24 hours post infusion. Additionally, bone marrow shear-strain was assessed radiographically with IO infusions.

RESULTS

Fat intravasation was observed during all IO infusion regimens, with subclinical pulmonary fat emboli persisting 24 hours post infusion. It was noted that initial flush was a significant factor in fat intravasation, low levels of intravasation occurred with infusions ≤300 mmHg, fat intravasation and bone marrow shear-strain increased with IO infusion rates, and intravasation was influenced by cannula insertion site. Ultrasound findings suggest that echogenic particles consistent with fat emboli are carried in fast and slow venous blood flow fields. Echo reflective densities were observed to rise to the nondependent endovascular margins and coalesce in accordance with Stoke's law. In addition, ultrasound findings suggested that intravasated bone marrow fat was thrombogenic.

CONCLUSION

Results suggest that in swine the intravasation of bone marrow fat is a common consequence of IO infusion procedures and that its magnitude is influenced by the site of cannulation and infusion forces. Although the efficacy and benefits of IO infusions for emergent care are well established, emergency care providers also should be cognizant that infusion procedures affect bone marrow fat intravasation.