Military anti-shock garment: Historical relic or a device with unrealized potential?

Assessing the influence of abdominal compression on time to return of circulation during resuscitation of asphyxiated newborn lambs: a randomised preclinical study

OBJECTIVE

During neonatal resuscitation, the return of spontaneous circulation (ROSC) can be achieved using epinephrine which optimises coronary perfusion by increasing diastolic pressure. Abdominal compression (AC) applied during resuscitation could potentially increase diastolic pressure and therefore help achieve ROSC. We assessed the use of AC during resuscitation of asystolic newborn lambs, with and without epinephrine.

METHODS

Near-term fetal lambs were instrumented for physiological monitoring and after delivery, asphyxiated until asystole. Resuscitation was commenced with ventilation followed by chest compressions. Lambs were randomly allocated to: intravenous epinephrine (20 µg/kg, n=9), intravenous epinephrine+continuous AC (n=8), intravenous saline placebo (5 mL/kg, n=6) and intravenous saline+AC (n=9). After three allocated treatment doses, rescue intravenous epinephrine was administered if ROSC had not occurred. Time to achieve ROSC was the primary outcome. Lambs achieving ROSC were ventilated and monitored for 60 min before euthanasia. Brain histology was assessed for micro-haemorrhage.

RESULTS

Use of AC did not influence mean time to achieve ROSC (epinephrine lambs 177 s vs epinephrine+AC lambs 179 s, saline lambs 602 s vs saline+AC lambs 585 s) or rate of ROSC (nine of nine lambs, eight of eight lambs, one of six lambs and two of eight lambs, respectively). Application of AC was associated with higher diastolic blood pressure (mean value >10 mm Hg), mean and systolic blood pressure and carotid blood flow during resuscitation. Cortex and deep grey matter micro-haemorrhage was more frequent in AC lambs.

CONCLUSION

Use of AC during resuscitation increased diastolic blood pressure, but did not impact time to ROSC.

Effect of the Abdominal Aortic and Junctional Tourniquet on chest compressions in a swine model of ventricular fibrillation

INTRODUCTION

Mortality for out-of-hospital cardiac arrest is high when traditional chest compressions are used without adjuncts. The abdominal aortic and junctional tourniquet (AAJT) is a device with a wedge-shaped air bladder that occludes the aortic bifurcation, augmenting blood flow to the heart and brain. Previously, the addition of AAJT during chest compression led to an increase in rate of survival in a model of traumatic cardiac arrest.

HYPOTHESIS

This study was designed to determine if application of the AAJT would lead to more effective chest compressions as measured by improved hemodynamic parameters and an increased rate of return of spontaneous circulation (ROSC).

METHODS

Yorkshire swine (n = 6 per group) underwent general anesthesia and instrumentation. Ventricular fibrillation (Vfib) was electrically induced and animals were allocated into groups with or without the AAJT. The AAJT was inflated if selected after four minutes of compressions. Following a total of ten minutes of compressions, the animals entered into a ten-minute advanced cardiac life support phase. Hemodynamics and blood gas measurements were compared between groups.

RESULTS

ROSC or cardioversion from Vfib was not achieved in either group. The AAJT group had improved hemodynamic parameters with significantly higher carotid diastolic pressure and higher blood flow in the carotid artery (p = 0.016 and 0.028 respectively). However, no significant differences were observed with coronary perfusion pressure or end tidal CO2.

CONCLUSION

The AAJT did not confer a survival advantage during chest compressions, but hemodynamic improvements were observed while the AAJT was in place.

Hemodynamic response to non-pneumatic anti-shock compression garments in patients with renal dysfunction

Background

Patients with chronic kidney disease are at higher risk of developing cardiovascular disease. Chronic exposure to intermittent hemodialysis may be a source of added stress to the cardiovascular system; intradialytic hypotension is a common complication of hemodialysis, and repeated events may lead to hemodynamic stress and ischemic injuries. Administration of non-pneumatic compression stockings to the lower limbs has demonstrated hemodynamic stabilizing effects in other settings and may provide similar benefits in the kidney disease population. Therefore, we conducted this pilot study assessing the feasibility and tolerability of the application of non-pneumatic compression stockings to patients with kidney disease. We also assessed the changes in hemodynamic measurements following the application of the compression stockings to explore the biological feasibility of this being an effective intervention for intradialytic hypotension.

Methods

Fifteen individuals were enrolled in the study (5 healthy, 5 chronic kidney disease patients, and 5 dialysis patients). Outcomes including hemodynamic parameters such as cardiac output, peripheral vascular resistance, and blood pressure were measured using continuous pulse wave analysis. Changes in global longitudinal strain were measured via echocardiography. These outcome measurements were made before and after the application of compression stockings.

Results

All study participants tolerated the compression garments well and without complication. Hemodynamic response to lower body compression caused varying effects on cardiac output, mean arterial pressure and global longitudinal strain. Some individuals saw large improvements in hemodynamic parameters while in others the opposite effect was observed. No consistent response was elicited.

Conclusions

Application of compression stockings to patients with renal dysfunction is well-tolerated. However, significant variations in hemodynamic outcomes exist, and may be a barrier for larger scale trials without prior identification of specific patient characteristics indicating likely benefit from the application of external compression.

Trial registration

ClinicalTrials.gov, Identifier: NCT02915627, Registration Date: Sept 27, 2016.

Noninvasive diagnostics for extremity compartment syndrome following traumatic injury: A state-of-the-art review

Acute compartment syndrome (ACS) is a serious medical condition that can occur following traumatic injury to an extremity. If left undiagnosed, ACS can eventuate in amputation of the limb or even death. Because of this, fasciotomy to release the pressure within the muscle and restore tissue perfusion is often performed upon suspicion of ACS, as the sequelae to fasciotomy are less severe than those associated with not performing the fasciotomy. Currently, the "gold standard" of diagnosis is based on clinical assessment of such symptoms as pain out of proportion to the injury, obvious high pressure and swelling, pain on passive stretch of the muscles in the affected compartment, and deficits in sensory and/ormotor functions. Diagnosis is often confirmed using invasive measurements of intramuscular pressure (IMP); however, controversy exists as to how direct IMP measurement should be accomplished and threshold pressures for accurate diagnosis. Because of this and the attendant issues with invasive measurements, investigators have been searching over the last 25 years for a noninvasive means to quantitatively measure IMP or perfusion to the limb. The purpose of this review is to summarize the current state of the art of noninvasive devices that could potentially be used to diagnose ACS accurately and objectively. To do this, we divide the discussion into those medical devices that primarily measure mechanical surrogates of IMP (e.g., tissue hardness or myofascial displacement) and those that primarily measure indices of tissue perfusion (e.g., tissue oxygen saturation via near-infraredspectroscopy). While near-infrared spectroscopy-basedtechnologies have shown the most promise, whether such technologies will be of diagnostic benefit await the completion of ongoing clinical trials. LEVEL OF EVIDENCE: Systematic Review, level II.

History and significance of the trauma resuscitation flow sheet

There is little to no written information in the literature regarding the origin of the trauma flow sheet. This vital document allows programs to evaluate initial processes of trauma care. This information populates the trauma registry and is reviewed in nearly every Trauma Process Improvement and Patient Safety conference when discerning the course of patient care. It is so vital, a scribe is assigned to complete this documentation task for all trauma resuscitations, and there are continual process improvement efforts in trauma centers across the nation to ensure complete and accurate data collection. Indeed, it is the single most important document reviewed by the verification committee when evaluating processes of care at site visits. Trauma surgeons often overlook its importance during resuscitation, as recording remains the domain of the trauma scribe. Yet it is the first document scrutinized when the outcome is less than what is expected. The development of the flow sheet is not a result of any consensus statement, expert work group, or mandate, but a result of organic evolution due to the need for relevant and better data. The purpose of this review is to outline the origin, importance, and critical utility of the trauma flow sheet.

Conventional and Unconventional Lifesaving Therapies in an Adolescent With Amlodipine Ingestion

Amlodipine, a dihydropyridine calcium channel blocker, is commonly prescribed for the treatment of hypertension. Ingestion of an overdose leads to severe hypotension; if the hypotension is not treated, death may be imminent. Conventional and unconventional interventions were used to treat an adolescent who ingested a life-threatening dose of amlodipine. Severe hypotension resistant to conventional treatment with intralipids and hyperinsulinemia-euglycemia therapy led to the use of plasmapheresis and a pneumatic antishock garment as lifesaving measures. Plasmapheresis has been described in only one other case of severe amlodipine overdose, and the use of a pneumatic antishock garment has never been described in the management of a calcium channel blocker overdose. Because short-term use of a pneumatic antishock garment has associated risks, the critical care nurse's anticipation of side effects and promotion of safe use of the garment were instrumental in the patient's care and outcome. (Critical Care Nurse 2016; 36[4]:64-69).

Gradient compression garments protect against orthostatic intolerance during recovery from bed rest

INTRODUCTION

Abdomen-high, lower body graded compression garments (GCGs) may represent the next-generation of orthostatic intolerance protection with applications for exploration missions and commercial space flight.

PURPOSE

To evaluate the efficacy of the GCG to prevent orthostatic intolerance after a 14-day 6° head-down tilt bed rest (BR) and to determine whether wearing thigh-high compression garments impairs recovery from BR.

METHODS

Sixteen (12 M, 4 F) subjects participated in a 15-min 80° head-up tilt test 5 day before BR (BR-5), on the last morning of BR (BR+0), and on day 1 (BR+1) and 3 after BR (BR+3). No subjects wore the GCG on BR-5, and all subjects wore the GCG during testing on BR+0. Control subjects (n = 8) wore the GCG only through testing on BR+0. Treatment subjects (n = 8) wore the GCG on BR+0 and thigh-high garments on BR+1 and BR+2.

RESULTS

No subjects were presyncopal during tilt on BR+0 while wearing the GCG. Despite lower plasma volume index (BR-5: 1.52 ± 0.06, BR+0: 1.32 ± 0.05 l/m(2)), the tilt-induced increase in heart rate (ΔHR, 17 ± 2 bpm) and decrease in stroke volume (ΔSV, -28 ± 3 ml) on BR+0 were less than on BR-5 (24 ± 2 bpm, -43 ± 4 ml). On BR+1 ΔHR in the control group (33 ± 4 bpm) was higher than in the treatment group (23 ± 2 bpm) but there were no group differences on BR+3.

CONCLUSIONS

Wearing the GCG prevented the orthostatic intolerance that is normally present after BR. Thigh-high garments provided protection after BR, and wearing these garments did not impair recovery.

Auto-transfusion tourniquets: the next evolution of tourniquets

In this article, we discuss the relationship between hemorrhagic shock and the pathophysiology of shock using conventional tourniquets. We will focus on corollary benefits with the use of HemaClear(®), a self-contained, sterile, exsanguinating auto-transfusion tourniquet. This discussion will demonstrate that the use of auto-transfusion tourniquets is a practical evidence-based approach in fluid resuscitation: it shortens the duration of shock after hemorrhage and trauma compared with conventional tourniquets. Emphasis is placed on the use of the HemaClear(®) as an alternative fluid resuscitation tool which is more efficient in the battlefield, pre-hospital and in-hospital settings.