Acute kidney injury is associated with worse outcomes after cardiac surgery. The haemodynamic goals to ameliorate kidney injury are not clear. Low post-operative renal perfusion pressure has been associated with acute kidney injury in adults. Inadequate oxygen delivery may also cause kidney injury. This study evaluates pressure and oximetric haemodynamics after paediatric cardiac surgery and their association with acute kidney injury.

Retrospective case–control study at a children’s hospital. Patients were < 6 months of age who underwent a Society of Thoracic Surgery-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery categories ≥ 3. Low renal perfusion pressure was time and depth below several tested thresholds. The primary outcome was serum creatine-defined acute kidney injury in the first 7 days.

Sixty-six patients (median age 8 days) were included. Acute kidney injury occurred in 36%. The time and depth of renal perfusion pressure < 42 mmHg in the first 24 hours was greater in acute kidney injury patients (94 versus 35 mmHg*minutes of low renal perfusion pressure/hour, p = 0.008). In the multivariable model, renal perfusion pressure < 42 mmHg was associated with acute kidney injury (aOR: 2.07, 95%CI: 1.25–3.82, p = 0.009). Mean arterial pressure, central venous pressure, and measures of inadequate oxygen delivery were not associated with acute kidney injury.

Periods of low renal perfusion pressure (<42 mmHg) in the first 24 post-operative hours are associated with acute kidney injury. Renal perfusion pressure is a potential modifiable target that may mitigate the impact of acute kidney injury after paediatric cardiac surgery.

Patients with ventricular assist devices (VADs) represent a growing population presenting to Emergency Medical Services (EMS), but little is known about their prehospital care. This study aimed to characterize current EMS protocols in the United States for patients with VADs.

States with state-wide EMS protocols were included. Protocols were obtained from the state EMS website. If not available, the office of the state medical director was contacted. For each state, protocols were analyzed for patient and VAD assessment and treatment variables.

Of 32 states with state-wide EMS protocols, 21 had VAD-specific protocols. With 17 (81%) states noting a pulse may not be palpable, protocols recommended assessing alternate measures of perfusion and mean arterial pressure (MAP; 15 [71%]). Assessment of VAD was advised through listening for pump hum (20 [95%]) and alarms (20 [95%]) and checking the power supply (15 [71%]). For treatment, EMS prehospital consultation was required to begin chest compression in three (14%) states, and mechanical (device) chest compressions were not permitted in two (10%) states. Contact information for VAD coordinator was listed in a minority of five (24%) states. Transport of VAD equipment/backup bag was advised in 18 (86%) states.

This national analysis of EMS protocols found VAD-specific EMS protocols are not universally adopted in the United States and are variable when implemented, highlighting a need for VAD teams to partner with EMS agencies to inform standardized protocols that optimize these patients’ care.

Acute coronary syndromes (ACS) are hard to diagnose because their clinical presentation is broad. Current guidelines suggest early clinical risk stratification to the optimal site of care. The aim of this study was to investigate the ability of Thrombolysis in Myocardial Infarction (TIMI); History, Electrocardiogram, Age, Risk Factors, Troponin (HEART); and Global Registry of Acute Coronary Events (GRACE) risk scores to predict the development of major adverse cardiac events (MACE) and the angiographic severity of coronary artery disease (CAD) in patients diagnosed with non-ST-segment elevation acute coronary syndrome (NSTEACS) in the emergency department (ED). In addition, independent variables associated with the development of MACE were also examined.

This study is a prospective, observational, single-center study. All patients over 18 years of age who were planned to be hospitalized for pre-diagnosed NSTEACS (NSTEMI + UAP) were included in the study consecutively. Patients’ demographic information and all variables necessary for calculating risk scores (TIMI, HEART, and GRACE) were recorded. Two experienced cardiologists evaluated all coronary angiograms and calculated the Gensini score.

The median age was 60 (IQR: 18) years, and 220 (61.6%) were male of the 357 patients included in the study. In this study, 91 MACE (52 percutaneous coronary interventions [PCI], 28 coronary artery bypass graft [CABG], three cerebrovascular disease [CVD], and eight deaths) occurred. The 30-day MACE rate was 25.5%. The low-risk group constituted 40.0%, 1.4%, and 68.0% of the population, respectively, in TIMI, HEART, and GRACE scores. Multiple logistic regression models for predicting MACE, age (P = .005), mean arterial pressure (MAP; P = .015), and High-Sensitive Troponin I (P = .004) were statistically significant.

The ability of the GRACE, HEART, and TIMI risk scores to predict severe CAD in patients with NSTEACS is similar. In patients with NSTEACS, the HEART and GRACE risk scores can better predict the development of MACE than the TIMI risk score. When low-risk groups are evaluated according to the three risk scores, the HEART score is more reliable to exclude the diagnosis of NSTEACS.

Acute gastroenteritis (AGE) is one of the most common clinical diagnoses globally, and dehydration in severe AGE cases can cause severe morbidity and mortality. Depending on the metabolic acidosis that occurs in dehydration, the respiratory rate per minute is increased, and the carbon dioxide pressure in the arterial blood is decreased. This condition correlates with end-tidal carbon dioxide (ETCO2). Therefore, this study primarily aims to evaluate whether ETCO2 measurement has a role in detecting metabolic fluid deficit, dehydration level, and regression in dehydration level after fluid replacement and its correlation with Vena Cava Collapsibility Index (VCCI).

This study included spontaneously breathing patients admitted to the emergency department of a tertiary training and research hospital with symptoms of AGE and were thought to be moderately (6.0%-9.0%) and severely (>10.0%) dehydrated according to the Primary Options of Acute Care (POAC) Clinical Dehydration Scale. After the first evaluation, the patients’ vital signs, ETCO2 values, diameters of the inferior vena cava (IVC) in inspiration and expiration, and VCCI were measured and recorded. These measurements were repeated after intravenous (IV) fluid replacement, and finally, a comparison was made between the measurements.

A total of 49 patients, as 16 male (32.7%) and 33 female (67.3%), were included in the study. The mean fluid replacement value was calculated as 664.29 (SD = 259.41) ml. The mean increase in ETCO2 was 3.653 (SD = 2.554) mmHg (P <.001). The mean increase in inferior vena cava expirium (IVCexp) was calculated as 0.402 (SD = 0.280) cm (P <.001) and the mean increase in inferior vena cava inspirium (IVCinsp) as 0.476 (SD = 0.306) cm (P <.001). The VCCI (%) decreased by 12.556 (SD = 13.683) (P <.001). Post-replacement vital signs, ETCO2, and VCCI correlations of the patients were examined and no significant correlation was found between ETCO2 and VCCI (%). As a result of this study, a receiver operating characteristic (ROC) curve was established for the ETCO2 values predicting the level of dehydration and fluid response, and the area under the curve was calculated as 0.748. However, to classify the patient as moderately dehydrated, the ETCO2 cutoff value was determined as 28.5mmHg.

The sensitivity and specificity of ETCO2 levels were 71.43% and 74.29% in evaluating the level of dehydration, and no correlation was found with VCCI, which is known to have high sensitivity and specificity in previous studies in determining the level of dehydration and fluid response. Hence, VCCI measurement made through ultrasonography (USG) is a method that should be preferred more in determining the level of dehydration. Nevertheless, as per the results of this study, swift ETCO2 measurements may be helpful in monitoring the change in the degree of dehydration with treatment in patients who were admitted to the emergency department with dehydration findings and were administered IV fluid replacement therapy.

The use of a long backboard and cervical collar are commonly recommended by international guidelines for spinal immobilization, but both devices may cause several side effects. In a recent study, it was reported that spinal immobilization at 20° eliminated the decrease in pulmonary function secondary to spinal immobilization performed at 0°. Spinal immobilization at 20° is a new recommendation, but other potential effects need to be explored before it can be implemented in clinical use.

Hemodynamic observation is important in the management of trauma patients. The aim of this study was to investigate the effect of spinal immobilization at a 20° position instead of 0° on hemodynamic parameters.

This study included 53 healthy volunteers who underwent spinal immobilization in the supine position (00) and in an elevated position (200). Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), left ventricular outflow tract velocity time integral (LVOT-VTI), left ventricular stroke volume (LVSV), cardiac output (CO), inferior vena cava diameter inspiration (IVC diameter insp), IVC diameter expiration (IVC diameter exp), and inferior vena cava collapsibility index (IVC-CI) were measured at the 0th and 30th minutes of spinal immobilization in both positions. The data were compared for demonstrating the efficiency of both positions in spinal immobilization.

A statistically significant difference was found in the parameters of the IVC diameter (exp), IVC diameter (insp), LVOT-VTI, LVSV, and CO through the measurements starting in the 0th minute of the transition from 0° to 20° (P <.001). Delta values (∆) of hemodynamic parameters (∆IVC diameter [exp], ∆IVC diameter [insp], ∆LVOT-VTI, ∆SV, ∆CO, ∆IVC-CI, ∆MAP, ∆SAP, ∆DAP, and ∆HR) were similar in spinal immobilization at 0° and 20°.

The findings obtained from this study illustrate that spinal immobilization at 20° does not cause clinically significant hemodynamic changes in healthy subjects compared to spinal immobilization at 0°.

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.

Emergency physicians are using bolus-dose vasopressors to temporize hypotensive patients until more definitive blood pressure support can be established. Despite a paucity of clinical outcome data, emergency department applications are expanding into the prehospital setting. This series presents two cases of field expedient vasopressor use by emergency medicine providers for preflight stabilization during aeromedical evacuation to a hospital ship as part of the United States Navy disaster response in Puerto Rico. A critical approach and review of the literature are discussed.

Two critically ill patients were managed in an austere environment as a result of the devastation from Hurricane Maria (Yabucoa, Puerto Rico; 2017). They both exhibited signs of respiratory distress, hemodynamic instability, and distributive shock requiring definitive airway management and hemodynamic support prior to aeromedical evacuation.

The novel use of field expedient vasopressors prior to induction for rapid sequence intubation was successfully and safely employed in both cases. Both patients had multiple risk factors for peri-induction cardiac arrest given their presenting hemodynamics. Despite their illness severity, both patients were induced, transported, and ultimately admitted to the intensive care unit (ICU) in stable condition following administration of the field expedient vasopressors.

Field expedient vasopressors were safely and effectively employed in an austere field environment during a disaster response. This case series contributes to the growing body of literature of safe bolus-dose vasopressor use by emergency physicians to temporize hypotensive patients in resource-constrained situations.

HardwickJM, MurnanSD, Morrison-PonceDP, DevlinJJ. Field Expedient Vasopressors During Aeromedical Evacuation: A Case Series from the Puerto Rico Disaster Response. Prehosp Disaster Med. 2018;33(6):668–672.

Invasive blood pressure (IBP) monitoring could be of benefit for certain prehospital patient groups such as trauma and cardiac arrest patients. However, there are disadvantages with using conventional IBP devices. These include time to prepare the transducer kit and flush system as well as the addition of long tubing connected to the patient. It has been suggested to simplify the IBP equipment by replacing the continuous flush system with a syringe and a short stopcock.

In this study, blood pressures measured by a standard IBP (sIBP) transducer kit with continuous flush was compared to a transducer kit connected to a simplified and minimized flush system IBP (mIBP) using only a syringe.

A mechanical, experimental model was used to create arterial pressure pulsations. Measurements were made simultaneously using a sIBP and mIBP device, respectively. This was repeated four times using different mean arterial pressure (MAP): 40, 70, 110, and 140mm Hg. For each series, 16 measurements were taken during 20 minutes. Data were analyzed using Bland-Altman plots. Measurement error greater than five percent was regarded as clinically significant.

Mean bias and standard deviation (SD) for systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP was -3.05 (SD = 2.07), 0.2 (SD = 0.48), and -0.3 (SD = 0.55) mmHg, respectively. Bland-Altman plots revealed that the bias and SD for systolic pressures was mainly due to an increased under-estimation of pressures in lower ranges. All MAP and 98.4% of diastolic pressure measurements had an error of less than five percent. Systolic pressures in the MAP 40 series all had an error of greater than five percent. All other systolic pressures had an error of less than five percent.

Thus, IBP with the mIBP flush system provides accurate measurement of MAP and DBP in a wide range of physiological pressures. For SBP, there was a tendency to under-estimate pressures, with larger error in lower pressures. Implementation of a simplified flush system could allow further development and potentially simplify the use of IBP for prehospital critical care teams.

KarlssonJ, LindeJ, SvensenC, GellerforsM. Prehospital Invasive Arterial Pressure: Use of a Minimized Flush System. Prehosp Disaster Med. 2018;33(5):490–494.

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.

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.