The relationship between intraosseous catheter tip placement, flow rates, and infusion pressures in a high bone density cadaveric swine (Sus scrofa) model.

Background: Intraosseous (IO) infusion is a life-preserving technique when intravenous access is unobtainable. Successful IO infusion requires sufficiently high flow rates to preserve life but at low enough pressures to avoid complications. However, IO catheter tips are often misplaced, and the relative flow rates and pressures between IO catheter tips placed in medullary, trabecular, and cortical bone are not well described, which has important implications for clinical practice. Objectives: We developed the Zone Theory of IO Catheter Tip Placement based on bone density and proximity to the venous central sinus and then tested the influence of catheter tip placement locations on flow rates and pressures in a cadaveric swine model. Methods: Three cross-trained participants infused 500 mL of crystalloid fluid into cadaveric swine humerus and sternum (N = 210 trials total) using a push‒pull method with a 60 cm3 syringe. Computed tomography scans were scored by radiologists and categorized as zone 1 (medullary space), zone 2 (trabecular bone), or zone 3 (cortical bone) catheter tip placements. Differences between zones in flow rates, mean pressures, and peak pressures were assessed using analysis of variance and analysis of covariance to account for participant and site differences at the p < 0.05 threshold. Results: Zone 1 and zone 2 placements were essentially identical in flow rates, mean pressures, and peak pressures (each p > 0.05). Zone 1 and zone 2 placements were significantly higher in flow rates and lower in pressures than zone 3 placements (each p < 0.05 or less). Conclusion: Within the limitations of an unpressurized cadaveric swine model, the present findings suggest that IO catheter tip placements need not be perfect to acquire high flow rates at low pressures, only accurate enough to avoid the dense cortical bone of zone 3. Future research using in vivo animal and human models is needed to better define the clinical impact of IO catheter placement on infusion flow rates and pressures.

Application Times, Placement Accuracy, and User Ratings of Commercially Available Manual and Battery-Powered Intraosseous Catheters in a High Bone Density Cadaveric Swine Model.

INTRODUCTION: Intraosseous (IO) infusion, the pressurized injection of fluids into bone through a catheter, is a life-preserving resuscitative technique for treating trauma patients with severe hemorrhage. However, little is known regarding the application times, placement accuracy, and end-user ratings of battery-powered and manual IO access devices. This study was specifically designed to fill these knowledge gaps on six FDA-approved IO access devices. MATERIALS AND METHODS: Three experienced U.S. Navy Emergency Medicine residents each placed commercially available 15-gauge IO catheters in cadaveric swine (Sus scrofa) proximal humeri and sternums in a randomized prospective experimental design. Devices included the battery-powered EZ-IO Rapid Infuser and the manual Jamshidi IO, PerSys NIO, SAM Manual IO, Tactical Advanced Lifesaving IO Needle (TALON), and PYNG First Access for Shock and Trauma 1 (30 trials per device, 10 per user, 210 total trials). Application times, placement accuracy in medullary (zone 1) and trabecular (zone 2) bone while avoiding cortical (zone 3) bone, and eight subjective user ratings were analyzed using ANOVA and nonparametric statistics at P < .05. RESULTS: The EZ-IO demonstrated the fastest application times, high rates in avoiding zone 3, and the highest user ratings (P < .0001). The TALON conferred intermediate placement times, highest rates of avoiding zone 3, and second-highest user ratings. The SAM Manual IO and Jamshidi performed poorly, with mixed results for the PerSys NIO and PYNG First Access for Shock and Trauma 1. CONCLUSIONS: The battery-powered EZ-IO performed best and remains the IO access device of choice. The present findings suggest that the TALON should be considered as a manual backup to the EZ-IO.

Performance comparison of intraosseous devices and setups for infusion of whole blood in a cadaveric swine bone model.

OBJECTIVES: Intraosseous (IO) access can provide a critical bridge for blood product infusion when peripheral venous access is not obtainable. Successful pressurized IO infusion requires flow rates sufficient to preserve life, but with infusion pressures low enough to avoid clinical complications (e.g., hemolysis, bone damage, fat emboli). However, the optimal method for pressured IO delivery of blood was unknown. METHODS: Three trained physicians infused 500 mL of whole blood through a 15-gauge, 45 mm IO catheter into fresh, high bone density cadaveric swine proximal humeri. Participants applied eight different pressure infusion strategies: (1) gravity, (2) pressure bag, (3) pressure bag actively maintained at or above 300 mmHg, (4) hand pump, (5) hand pump with pressure bag, (6) push-pull with 10 mL syringe, (7) push-pull with 60 mL syringe, and a (8) Manual Rapid Infuser in a randomized within-subjects design (30 trials per method, 240 trials total). The primary outcomes of flow rates, mean and peak pressures, and user ratings were contrasted using ANOVA at p < 0.05. RESULTS: The Manual Rapid Infuser conferred the highest flow rates (199 ± 3 mL/min) and most favorable user ratings, but also the highest mean and peak pressures. Push-pull conferred the next highest flow rates (67 ± 5 mL/min for 60 mL, 56 ± 2 mL/min for 10 mL) and pressures, with intermediate-to-high user ratings. Hand pump flow rates were essentially identical with (45 ± 4 mL/min) or without (44 ± 3 mL/min) pressure bag, with high user ratings without a pressure bag. Pressure bag and gravity methods conferred low flow rates and user ratings. CONCLUSIONS: Some pressured IO infusion methods can achieve flow rates adequate to serve as a resuscitative bridge in the massively hemorrhaged trauma victim, but flow rates and pressures vary greatly across IO pressurized infusion methods. Manual Rapid Infuser and push-pull methods conferred high flow rates but also relatively high pressures, highlighting the importance of using in vivo models in future research to assess the possible clinical complications of using these promising methods. Combined, present findings highlight the importance of studying pressurized IO methods towards preserving the life of the critically injured trauma victim.

Rapid Sequence Induction Strategies Among Critically Injured U.S. Military During the Afghanistan and Iraq Conflicts.

INTRODUCTION: Rapid sequence intubation of patients experiencing traumatic hemorrhage represents a precarious phase of care, which can be marked by hemodynamic instability and pulseless arrest. Military combat trauma guidelines recommend reduced induction dose and early blood product resuscitation. Few studies have evaluated the role of induction dose and preintubation transfusion on hemodynamic outcomes. We compared rates of postintubation systolic blood pressure (SBP) of < 70 mm Hg, > 30% drop in SBP, pulseless arrest, and mortality at 24 hours and 30 days among patients who did and did not receive blood products before intubation and then examined if induction agent and dose influenced the same outcomes. MATERIALS AND METHODS: A retrospective analysis was performed of battle-injured personnel presenting to surgical care facilities in Iraq and Afghanistan between 2004 and 2018. Those who received blood transfusions, underwent intubation, and had an Injury Severity Score of ≥15 were included. Intubation for primary head, facial, or neck injury, burns, operative room intubations, or those with cardiopulmonary resuscitation in progress were excluded. Multivariable logistic regression was performed with unadjusted and adjusted odds ratios for the five study outcomes among patients who did and did not receive preintubation blood products. The same analysis was performed for patients who received full or excessive versus partial induction agent dose. RESULTS: A total of 153 patients had a mean age of 24.9 (SD 4.5), Injury Severity Score 29.7 (SD 11.2), heart rate 122.8 (SD 24), SBP 108.2 (SD 26.6). Eighty-one (53%) patients received preintubation blood products and had similar characteristics to those who did not receive transfusions. Adjusted multivariate analysis found odds ratios as follows: 30% SBP decrease 9.4 (95% CI 2.3-38.0), SBP < 70 13.0 (95% CI 3.3-51.6), pulseless arrest 18.5 (95% CI 1.2-279.3), 24-hour mortality 3.8 (95% CI 0.7-21.5), and 30-day mortality 1.3 (0.4-4.7). In analysis of induction agent choice and comparison of induction agent dose, no statistically significant benefit was seen. CONCLUSION: Within the context of this historical cohort, the early use of blood products conferred a statistically significant benefit in reducing postintubation hypotension and pulseless arrest among combat trauma victims exposed to traumatic hemorrhage. Induction agent choice and dose did not significantly influence the hemodynamic or mortality outcomes.

Rapid Ketamine Infusion at an Analgesic Dose Resulting in Transient Hypotension and Bradycardia in the Emergency Department.

Ketamine's favorable hemodynamic and safety profile is motivating increasing use in the prehospital environment. Despite these advantages, certain side effects require advanced planning and training. We present a case of rapid intravenous administration of ketamine causing bradycardia and hypotension. A 46-year-old man presented to the emergency department for an exacerbation of chronic shoulder pain. Given the chronicity of the pain and multiple failed treatment attempts, ketamine at an analgesic dose was used. Despite the local protocol directing administration over several minutes, it was pushed rapidly, resulting in malaise, nausea, pallor, bradycardia, and hypotension. The patient returned to his baseline without intervention. This and other known side effects of ketamine, such as behavioral disturbances, altered sense of reality, and elevated heart rate and blood pressure, are well documented in the literature. With this report, the authors aim to raise awareness of transient bradycardia and hypotension associated with the rapid administration of ketamine at an analgesic dose.