Cardiac Arrest Following Drug Overdose in the United States: An Analysis of the Cardiac Arrest Registry to Enhance Survival.

BACKGROUND: Given increases in drug overdose-associated mortality, there is interest in better understanding of drug overdose out-of-hospital cardiac arrest (OHCA). A comparison between overdose-attributable OHCA and nonoverdose-attributable OHCA will inform public health measures. METHODS AND RESULTS: We analyzed data from 2017 to 2021 in the Cardiac Arrest Registry to Enhance Survival (CARES), comparing overdose-attributable OHCA (OD-OHCA) with OHCA from other nontraumatic causes (non-OD-OHCA). Arrests involving patients <18 years, health care facility residents, patients with cancer diagnoses, and patients with select missing data were excluded. Our main outcome of interest was survival with good neurological outcome, defined as Cerebral Performance Category score 1 or 2. From a data set with 537 100 entries, 29 500 OD-OHCA cases and 338 073 non-OD-OHCA cases met inclusion criteria. OD-OHCA cases involved younger patients with fewer comorbidities, were less likely to be witnessed, and less likely to present with a shockable rhythm. Unadjusted survival to hospital discharge with Cerebral Performance Category score =1 or 2 was significantly higher in the OD-OHCA cohort (OD: 15.2% versus non-OD: 6.9%). Adjusted results showed comparable survival with Cerebral Performance Category score =1 or 2 when the first monitored arrest rhythm was shockable (OD: 28.9% versus non-OD: 23.5%, P=0.087) but significantly higher survival rates with Cerebral Performance Category score =1 or 2 for OD-OHCA when the first monitored arrest rhythm was nonshockable (OD: 9.6% versus non-OD: 3.1%, P<0.001). CONCLUSIONS: Among patients presenting with nonshockable rhythms, OD-OHCA is associated with significantly better outcomes. Further research should explore cardiac arrest causes, and public health efforts should attempt to reduce the burden from drug overdoses.

Feasibility and Acceptance of a Teletrauma Surgery Consult Service to Rural and Community Hospitals: A Pilot Study.

BACKGROUND: Many trauma patients currently transferred from rural and community hospitals (RCH) to Level I trauma centers (LITC) for trauma surgery evaluation may instead be appropriate for immediate discharge or admission to the local facility after evaluation by a trauma and acute care surgery (TACS) surgeon. Unnecessary use of resources occurs with current practice. We aimed to demonstrate the feasibility and acceptance of a teletrauma surgery consultation service between LITC and RCH. STUDY DESIGN: LITC TACS surgeons provided telehealth consults on trauma patients from 3 local RCHs. After consultation, appropriate patients were transferred to LITC; selected patients remained at or were discharged from RCH. Participating TACS surgeons and RCH physicians were surveyed. RESULTS: A total of 28 patients met inclusion criteria during the 5-month pilot phase, with 7 excluded due to workflow issues. The mean ± SD age was 63 ± 17 years. Of 21 patients, 7 had intracranial hemorrhage; 12 had rib fractures. The mean ± SD Injury Severity Score was 8.1 ± 4.0). A total of 6 patients were discharged from RCH, 4 admitted to RCH hospitalist service, 2 transferred to a LITC emergency room, and 9 transferred to LITC as direct admission. There was one 30-day readmission and no missed injuries or complications, or deaths. RCH providers were highly satisfied with the teletrauma surgery consultation service, TACS surgeons, and equipment used. Mental demand and effort of consulting TACS surgeons decreased significantly as the consult number increased. CONCLUSIONS: Teletrauma surgery consultation involving 3 RCH within our system is feasible and acceptable. A total of 10 transfers and 19 emergency department visits were avoided. There was favorable acceptance by RCH providers and TACS surgeons.

Annual and lifetime economic productivity loss due to adult out-of-hospital cardiac arrest in the United States: A study for the CARES Surveillance Group.

OBJECTIVE: To estimate the annual and lifetime economic productivity loss due to adult out-of-hospital cardiac arrest (OHCA) in the United States (U.S.). METHODS: All adult (age ≥ 18 years) non-traumatic EMS-treated OHCA with complete data for age, sex, race, and survival outcomes from the CARES database for 2013-2018 were included. Annual and lifetime labor productivity values, based on age and gender, were obtained from previously published national economic data. Productivity losses for OHCA events were calculated by year in U.S. dollars. Productivity losses for survivors were assigned by cerebral performance category score (CPC): CPC 1 and 2 = 0% productivity loss; CPC 3-5 = 100% productivity loss. Sensitivity analyses were performed assigning CPC 2 varying productivity losses (0-100%) based on CPC score and discharge location. Lifetime productivity values assumed 1% annual growth and 3% discount rate and were adjusted for inflation based on 2016 values. Results were extrapolated to annual U.S. population estimates for the study period. RESULTS: A total of 338,492 (96.5%) cases met inclusion criteria. The mean annual and lifetime productivity losses per OHCA in 2018 were $48,224 and $638,947 respectively. The total annual economic productivity loss due to OHCA in the U.S. increased from $7.4B in 2013 to $11.3B in 2018. Lifetime economic productivity loss increased from $95.2B in 2013 to $150.2B in 2018. Sensitivity analyses yielded similar findings. Per annual death, OHCA ranked third ($10.2B) in annual economic productivity loss in the U.S. behind cancer ($22.9B) and heart disease ($20.3B) in 2018. CONCLUSION: Adult non-traumatic OHCA events are associated with significant annual and lifetime economic productivity losses and should be the focus of public health resources to improve preventative measures and survival outcomes.

Young patients with suspected uncomplicated renal colic are unlikely to have dangerous alternative diagnoses or need emergent intervention.

INTRODUCTION: In the United States there is debate regarding the appropriate first test for new-onset renal colic, with non-contrast helical computed tomography (CT) receiving the highest ratings from both Agency for Healthcare Research and Quality and the American Urological Association. This is based not only on its accuracy for the diagnosis of renal colic, but also its ability to diagnose other surgical emergencies, which have been thought to occur in 10-15% of patients with suspected renal colic, based on previous studies. In younger patients, it may be reasonable to attempt to avoid immediate CT if concern for dangerous alternative diagnosis is low, based on the risks of radiation from CTs, and particularly in light of evidence that patients with renal colic have a very high likelihood of having multiple CTs in their lifetimes. The objective is to determine the proportion of patients with a dangerous alternative diagnosis in adult patients age 50 and under presenting with uncomplicated (non-infected) suspected renal colic, and also to determine what proportion of these patients undergo emergent urologic intervention. METHODS: Retrospective chart review of 12 months of patients age 18-50 presenting with "flank pain," excluding patients with end stage renal disease, urinary tract infection, pregnancy and trauma. Dangerous alternative diagnosis was determined by CT. RESULTS: Two hundred and ninety-one patients met inclusion criteria. One hundred and fifteen patients had renal protocol CTs, and zero alternative emergent or urgent diagnoses were identified (one-sided 95% CI [0-2.7%]). Of the 291 encounters, there were 7 urologic procedures performed upon first admission (2.4%, 95% CI [1.0-4.9%]). The prevalence of kidney stone by final diagnosis was 58.8%. CONCLUSION: This small sample suggests that in younger patients with uncomplicated renal colic, the benefit of immediate CT for suspected renal colic should be questioned. Further studies are needed to determine which patients benefit from immediate CT for suspected renal colic, and which patients could undergo alternate imaging such as ultrasound.

An observational study to assess changes in arterial blood gas values during untreated porcine ventricular fibrillation.

BACKGROUND: Cardiocerebral resuscitation (CCR) is reportedly superior to cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) even though active ventilation is not initially provided. Understandably, concerns have been raised regarding the withholding of positive pressure ventilation (PPV) during CCR because of the longstanding belief that respiratory gas exchange is a critical action during resuscitation. OBJECTIVE: In this observational study, we sought to quantify the effect of prolonged untreated ventricular fibrillation (VF) on arterial pH, partial pressure of carbon dioxide (pCO(2)), and partial pressure of oxygen (pO(2)) values in a swine model of witnessed cardiac arrest to begin exploring the validity of these concerns. METHODS: Both included studies were approved by the institutional animal care and use committee (IACUC). Eighty-three animals (25-35 kg) were instrumented under general anesthesia. Baseline characteristics were recorded. An arterial blood gas (ABG) sample was drawn from each animal via femoral catheter just prior to electrical induction of VF. After 8 minutes of untreated VF in one study (study 1 [n = 30]) and 10 minutes of untreated VF in the other study (study 2 [n = 53]), a second ABG sample was drawn. All samples were processed immediately using an i-STAT portable whole blood analyzer. Baseline characteristics of animals in the two studies were assessed using descriptive statistics. For the second ABG sample in each study, the mean pH, pCO(2), and pO(2) values, with 95% confidence intervals (95% CIs), were determined. The paired ABG results for each animal were then compared and the average pH, pCO(2), and pO(2) proportions, with 95% CIs, for each study were calculated. RESULTS: The baseline characteristics of the animals in the two studies were similar. After 8 and 10 minutes of untreated VF cardiac arrest, the pH values were 7.35 (95% CI = 7.32, 7.37) and 7.37 (95% CI = 7.36, 7.38), the pCO(2) increased to 44.1 mmHg (95% CI = 41.1, 47.1) and 52.7 mmHg (95% CI = 51.0, 54.4), and the pO(2) decreased to 44.8 mmHg (95% CI = 42.2, 47.4) and 45.5 mmHg (95% CI = 43.3, 47.6), respectively. CONCLUSIONS: Using our swine model of witnessed cardiac arrest with prolonged untreated VF, the arterial pH remained essentially unchanged and the pCO(2) increased to 1.42 times baseline after 10 minutes, while almost half of the initial O(2) concentration in the blood at the beginning of resuscitation remained.

Gastric transmural pressure measurements in vivo: implications for natural orifice transluminal endoscopic surgery (NOTES).

BACKGROUND: The success of natural orifice surgery depends on a reliable, secure closure of the opening in the gut. Forces that might be exerted on the gastric wall to disrupt closure have not been measured in humans or animals. OBJECTIVE: To determine how transmural gastric pressure gradients vary under different experimental conditions. DESIGN: In vivo porcine model. SETTING: Animal laboratory. PATIENTS: Eleven laboratory pigs. INTERVENTIONS: Pressure transducers were placed in the abdomen and stomachs of the test animals. Simultaneous pressure measurements were obtained to determine the stresses applied to the gastric wall during various maneuvers. MAIN OUTCOME MEASUREMENTS: Continuous intra-abdominal and intragastric pressures in vivo. Transgastric pressure gradients (DeltaP) were computed in real time by subtracting gastric pressure from abdominal pressure. RESULTS: In all cases, the measured gastric pressures were nearly identical to those measured in the abdominal cavity because the stomach is entirely contained within the abdomen. The transmural gastric pressure gradients were near zero during a variety of experimental conditions. LIMITATION: Anesthetized animal model, not engaged in usual activities. Relatively low pressures generated during a cough sequence and a Valsalva maneuver compared with reported values in the literature. CONCLUSION: Estimates of gastric pressures that must be tolerated by gastric closure devices after natural orifice transluminal endoscopic surgery procedures have been greatly overestimated. Absolute gastric pressure is counteracted by external (intra-abdominal) pressure such that the net transmural gastric pressure gradient remains near zero under a variety of conditions.

The effect of adenosine A1 receptor antagonism on return of spontaneous circulation and short-term survival in prolonged ventricular fibrillation.

BACKGROUND: Endogenous adenosine (ADO) is cardioprotective during ischemia and its myocardial concentration increases during untreated ventricular fibrillation (VF). We have previously shown that ADO A1 receptor (ADOA1R) antagonism hastens the time-dependent decay in VF waveform morphology during the circulatory phase of cardiac arrest. OBJECTIVE: To determine the effect of ADOA1R antagonism on ROSC and short-term survival in prolonged VF. METHODS: Thirty-six swine were assigned by block randomization to one of three groups: a group that received only vehicle (CONTROL), an ADOA1R antagonist pretreatment group (PRE), and a group that was given ADOA1R antagonist during resuscitation (DURING). The animals were instrumented under anesthesia, and ADOA1R antagonist or vehicle, per group assignment, was infused 5 minutes prior to VF induction. At minute 8 of untreated VF, chest compression with ventilation was initiated and a standard drug cocktail, with ADOA1R antagonist or vehicle, was given. The first rescue shock (150 J biphasic) was delivered after 11 minutes of VF. Proportions with 95% confidence intervals (CIs) were calculated for the two outcome measures. RESULTS: The baseline characteristics and chemistry values for the three groups were mathematically the same. The DURING group had a greater proportion of female animals (seven of 12) in comparison with the CONTROL group (two of 12) (p=0.03). ADOA1R antagonism hastened the decay of VF as previously demonstrated, but the rate of ROSC was the same for all groups: CONTROL=seven of 12, PRE=six of 12, and DURING=seven of 12. There were also no differences in short-term survival: CONTROL=four of 12, PRE=five of 12, and DURING=seven of 12. CONCLUSIONS: In this study, ADOA1R antagonism had no effect on outcome whether given before induction of VF or upon resuscitation after 8 minutes of untreated VF. The role of endogenous ADO in prolonged VF remains unclear.

Adenosine A1 receptor antagonism hastens the decay in ventricular fibrillation waveform morphology during porcine cardiac arrest.

BACKGROUND: Endogenous adenosine (ADO) is known to be cardioprotective during acute myocardial ischemia. Coronary sinus ADO concentration has recently been shown to increase nearly 13-fold over baseline levels after 5 min of untreated ventricular fibrillation (VF). The role of ADO in VF has never been previously examined. The objective of this study was to determine the effect of ADO receptor antagonism, as measured by the scaling exponent (ScE), on the degeneration of VF over time during the circulatory phase of cardiac arrest. METHODS AND RESULTS: A well-established swine model of prolonged VF arrest was used for this experiment. Eighteen domestic mixed-breed swine were assigned by block randomization to receive either DTI-0017 (5mg/kg), a potent ADO A(1) receptor antagonist or placebo in a double-blind fashion. The animals were instrumented under general anesthesia and acclimatized. The assigned solution was infused over 5 min. One minute after the infusion was completed, VF was induced with a 3s, 60 Hz, 100 mA transthoracic shock and left untreated. Lead II ECG was monitored continuously and recorded at 1000 samples/s. It was determined a priori that evaluation of the plots would be limited to a previously observed plateau phase historically occurring between 5 and 8 min corresponding to the circulatory phase of cardiac arrest. The scaling exponent values over this period were calculated for each of the 18 recordings using custom MATLAB routines. Using the Wald statistic to produce the Chi square distributions the null hypothesis, that there was no difference between the two groups, was tested. The Wald statistic calculation based on eight epochs from 300 to 475 s in placebo and DTI groups was significant to reject the null hypothesis of no difference in the groupxtime interaction at the 0.015 level (Chi square distribution for Wald=17.49, d.f.=7). CONCLUSIONS: In this swine model, adenosine A(1) receptor antagonism accelerated the natural decay in the ECG VF waveform during the circulatory phase of cardiac arrest. Our findings would suggest that endogenous adenosine has cardioprotective effects during sudden cardiac arrest by slowing the time-dependent degeneration of VF.

A randomized controlled trial of intravenous aminophylline for atropine-resistant out-of-hospital asystolic cardiac arrest.

OBJECTIVES: Myocardial ischemia, during cardiopulmonary arrest, can lead to atropine-resistant bradyasystole from interstitial accumulation of endogenous adenosine. Aminophylline is a nonspecific adenosine receptor antagonist capable of reversing ischemia-induced bradyasystole in a variety of settings. The hypothesis of this study was that aminophylline improves the rate of return of spontaneous circulation (ROSC) in atropine-resistant asystolic out-of-hospital cardiac arrest when used early in the resuscitation effort. METHODS: This was a prospective, randomized, double-blinded, placebo-controlled trial set in an urban emergency medical services system serving a population of 250,000. All non-pregnant, normothermic adults suffering nontraumatic out-of-hospital cardiac arrest (February 1999 to August 2000) with asystole were eligible. Patients remaining in asystole after initial doses of epinephrine and atropine received either aminophylline 250 mg or matching placebo as a bolus injection through a peripheral intravenous line. All other aspects of the attempted resuscitation proceeded in accordance with standard Advanced Cardiac Life Support (ACLS) guidelines. A sample size of 102 patients was calculated to yield a power of 80% to show an absolute improvement of 25% in ROSC. The aminophylline and control groups were compared by calculating 95% confidence intervals (95% CIs) and the data were modeled using logistic regression. RESULTS: The investigators enrolled 112 consecutive patients. One subject was dropped prior to analysis because of missing data. Data for 111 patients were analyzed on an intention-to-treat basis. Baseline characteristics were similar for the two groups. Comparing the control and aminophylline groups, ROSC was achieved in 15.6% (95% CI = 6% to 29%) and 22.7% (95% CI = 13% to 35%), while reversal of asystole occurred in 26.7% (95% CI = 15% to 42%) and 40.9% (95% CI = 29% to 54%), respectively. Group allocation had an odds ratio of 1.8 (95% CI = 0.6 to 5.3) for ROSC. Witnessed arrest was an independent predictor of outcome with an odds ratio of 3.8 (95% CI = 1.3 to 11.2). CONCLUSIONS: Addition of aminophylline appears to be a promising new intervention in the ACLS treatment of atropine-resistant asystolic out-of-hospital cardiac arrest.