Thomas Blackwell

The Association Between Prehospital Endotracheal Intubation Attempts and Survival to Hospital Discharge Among Out-of-hospital Cardiac Arrest Patients

OBJECTIVES The benefit of prehospital endotracheal intubation (ETI) among individuals experiencing out-of-hospital cardiac arrest (OOHCA) has not been fully examined. The objective of this study was to determine if prehospital ETI attempts were associated with return of spontaneous circulation (ROSC) and survival to discharge among individuals experiencing OOHCA. METHODS This retrospective study included individuals who experienced a medical cardiac arrest between July 2006 and December 2008 and had resuscitation efforts initiated by paramedics from Mecklenburg County, North Carolina. Outcome variables were prehospital ROSC and survival to hospital discharge, while the primary independent variable was the number of prehospital ETI attempts. RESULTS There were 1,142 cardiac arrests included in the analytic data set. Prehospital ROSC occurred in 299 individuals (26.2%). When controlling for initial arrest rhythm and other confounding variables, individuals with no ETI attempted were 2.33 (95% confidence interval [CI] = 1.63 to 3.33) times more likely to have ROSC compared to those with one successful ETI attempt. Of the 299 individuals with prehospital ROSC, 118 (39.5%) were subsequently discharged alive from the hospital. Individuals having no ETI were 5.46 (95% CI = 3.36 to 8.90) times more likely to be discharged from the hospital alive compared to individuals with one successful ETI attempt. CONCLUSIONS Results from these analyses suggest a negative association between prehospital ETI attempts and survival from OOHCA. In this study, the individuals most likely to have prehospital ROSC and survival to hospital discharge were those who did not have a reported ETI attempt. Further comparative research should assess the potential causes of the demonstrated associations.

Resuscitation in the out-of-hospital setting: Medical futility criteria for on-scene pronouncement of death

The complete and irreversible cessation of life is often difficult to determine with complete confidence in the dynamic environment of out-of-hospital emergency care. As a result, resuscitation efforts often are initiated and maintained by emergency medical services (EMS) providers in many hopeless situations. Medical guidelines are reviewed here to aid EMS organizations with respect to decisions about: 1) initiating or waiving resuscitation efforts; 2) the appropriate duration of resuscitation efforts; and 3) recommended procedures for on-scene or prehospital pronouncement of death (termination of resuscitation). In cases of nontraumatic cardiac arrest, few unassailable criteria, other than certain physical signs of irreversible tissue deterioration, exist for determining medical futility at the initial encounter with the patient. Thus, the general medical recommendation is to attempt to resuscitate all patients, adult or child, in the absence of rigor mortis or dependent lividity. Conversely, well-founded guidelines now are available for decisions regarding termination of resuscitation in such patients once they have received a trial of advanced cardiac life support. In practice, however, the final decision to proceed with on-scene pronouncement of death for these patients may be determined more by family and provider comfort levels and the specific on-scene environment. For patients with posttraumatic circulatory arrest, the type of injury (blunt or penetrating), the presence of vital signs, and the electrocardiographic findings are used to determine the futility of initiating or continuing resuscitation efforts. In general, patients who are asystolic on-scene are candidates for on-scene pronouncement, regardless of mechanism. With a few exceptions, blunt trauma patients with a clearly associated mechanism of lethal injury are generally candidates for immediate cessation of efforts once they lose their pulses and respirations. Regardless of the medical futility criteria, specialized training of EMS providers and targeted related testing of operational issues need to precede field implementation of on-scene pronouncement policies. Such policies also must be modified and adapted for local issues and resources. In addition, although the current determinations of medical futility, as delineated here, are important to establish for societal needs, the individual patients right to live must be kept in mind always as new medical advances are developed.

Association Between Prehospital Time Intervals and ST-Elevation Myocardial Infarction System Performance

Background— Among individuals experiencing an ST segment–elevation myocardial infarction, current guidelines recommend that the interval from first medical contact to percutaneous coronary intervention be ≤90 minutes. The objective of this study was to determine whether prehospital time intervals were associated with ST-elevation myocardial infarction system performance, defined as first medical contact to percutaneous coronary intervention. Methods and Results— Study patients presented with an acute ST-elevation myocardial infarction diagnosed by prehospital ECG between May 2007 and March 2009. Prehospital time intervals were as follows: 9-1-1 call receipt to ambulance on scene ≤10 minutes, ambulance on scene to 12-lead ECG acquisition ≤8 minutes, on-scene time ≤15 minutes, prehospital ECG acquisition to ST-elevation myocardial infarction team notification ≤10 minutes, and scene departure to patient on cardiac catheterization laboratory table ≤30 minutes. Time intervals were derived and analyzed with descriptive statistics and logistic regression. There were 181 prehospital patients who received percutaneous coronary intervention, with 165 (91.1%) having complete data. Logistic regression indicated that table time, response time, and on-scene time were the benchmark time intervals with the greatest influence on the probability of achieving percutaneous coronary intervention in ≤90 minutes. Individuals with a time from scene departure to arrival on cardiac catheterization laboratory table of ≤30 minutes were 11.1 times (3.4 to 36.0) more likely to achieve percutaneous coronary intervention in ≤90 minutes than those with extended table times. Conclusions— In this patient population, prehospital timing benchmarks were associated with system performance. Although meeting all 5 benchmarks may be an ideal goal, this model may be more useful for identifying areas for system improvement that will have the greatest clinical impact.

Bioterrorism preparedness: II: the community and emergency medical services systems

Disaster planning is an arduous task. Perhaps no form of disaster is more difficult to prepare for than one resulting from the intentional, covert release of a biological pathogen or toxin. The complexities of response operations and the perils of inadequate preparation cannot be overemphasized. Even with detailed planning, deviations from anticipated emergency operations plans are likely to occur. Several federal programs have been initiated to assist communities in enhancing their preparedness for events involving biological and other agents of mass destruction. Many of these, such as the Metropolitan Medical Response Systems (MMRS) Program [37,38], will be discussed elsewhere. Community preparedness will be enhanced by: 1. Implementing a real-time public health disease surveillance program linking local healthcare, emergency care, EMS, the CDC, local law enforcement, and the FBI 2. Improved real-time regional patient and healthcare capacity status management 3. Development of affordable, accurate biological agent detection systems 4. Incorporation of standardized education and training curricula (appropriate for audience) on terrorism and biological agents into healthcare training programs 5. Expansion of federal and state programs to assist communities in system development 6. Increased public awareness and education programs.

Needle Thoracostomy for Tension Pneumothorax: Failure Predicted by Chest Computed Tomography

Objective. Tension pneumothorax can lead to cardiovascular collapse and death. In the prehospital setting, needle thoracostomy for emergent decompression may be lifesaving. Taught throughout the United States to emergency medical technicians (EMTs) and physicians, the true efficacy of this procedure is unknown. Some question the utility of this procedure in the prehospital setting, doubting that the needle actually enters the pleural space. This study was designed to determine if needle decompression of a suspected tension pneumothorax would access the pleural cavity as predicted by chest computed tomography (CT). Methods. We retrospectively reviewed consecutive adult trauma patients admitted to a level I trauma center between January and March 2005. We measured chest wall depth at the second intercostal space, midclavicular line on CT scans. Data on chest wall thickness were compared with the standard 4.4-cm angiocatheter used for needle decompression. Results. Data from 110 patients were analyzed. The mean age of the patients was 43.5 years. The mean chest wall depth on the right was 4.5 cm (± 1.5 cm) and on the left was 4.1 cm (± 1.4 cm). Fifty-five of 110 patients had at least one side of the chest wall measuring greater than 4.4 cm. Conclusions. The standard 4.4-cm angiocatheter is likely to be unsuccessful in 50% (95% confidence interval = 40.7–59.3%) of trauma patients on the basis of body habitus. In light of its low predicted success, the standard method for treatment of tension pneumothorax by prehospital personnel deserves further consideration.

The association between intra-arrest therapeutic hypothermia and return of spontaneous circulation among individuals experiencing out of hospital cardiac arrest

INTRODUCTION Therapeutic hypothermia has been shown to improve both mortality and neurologic outcomes following pulseless ventricular tachycardia and fibrillation. Animal data suggest intra-arrest induction of therapeutic hypothermia (IATH) improves frequency of return of spontaneous circulation (ROSC). Our objective was to evaluate the association between IATH and ROSC. METHODS This was a retrospective analysis of individuals experiencing non-traumatic cardiac arrest in a large metropolitan area during a 12-month period. Six months into the study a prehospital IATH protocol was instituted whereby patients received 2000ml of 4°C normal saline directly after obtaining IV/IO access. The main outcome variables were prehospital ROSC, survival to admission, and to discharge. A secondary analysis was conducted to assess the relationship between the quantity of cold saline infused and the likelihood of prehospital ROSC. RESULTS 551 patients met inclusion criteria with all the elements available for data analysis. Rates of prehospital ROSC were 36.5% versus 26.9% (OR 1.83; 95% CI 1.19-2.81) in patients who received IATH versus normothermic resuscitation respectively. While the frequency of survival to hospital admission and discharge were increased among those receiving IATH, the differences did not reach statistical significance. The secondary analysis found a linear association between the amount of cold saline infused and the likelihood of prehospital ROSC. CONCLUSION The infusion of 4°C normal saline during the intra-arrest period may improve rate of ROSC even at low fluid volumes. Further study is required to determine if intra-arrest cooling has a beneficial effect on rates of ROSC, mortality, and neurologic function.

Trauma care systems in the United States

The trauma system in the United States is in the process of evolution. Although it is recognised that a systems approach to trauma care is ideal, this concept has yet to be realised fully due to political, financial and geographic considerations. The pre-hospital controversies of in-the-field care, resuscitation, and transport are still debated. In-hospital care is governed by a trauma service using the guidelines of the American College of Surgeons (ACS). Speciality care is usually delivered as a consultative service at the request of the trauma service. Co-ordination by the trauma surgeon assures appropriate timing and amount of care by the specialities. Problems facing the delivery of trauma care are malpractice, reimbursement for speciality trauma care call and the need to extend the system to all trauma patients.

Lack of Association Between Prehospital Response Times and Patient Outcomes

Background. Limited data exist that examine the relationship between prehospital response times (RTs) and improved patient outcomes. Objective. We tested the hypothesis that patient outcomes do not differ substantially based on an explicitly chosen advanced life support (ALS) RT upper limit of 10 minutes 59 seconds (10:59 minutes). Methods. This case–control retrospective study was conducted in a metropolitan county with a population of 750,000 for the calendar year 2004. The emergency medical services (EMS) system is a single-tiered, ALS paramedic service that includes basic life support (BLS) first responders. The 90% fractile RT specification required by contractual agreement is 10:59 minutes or less for emergency, life-threatening (Priority 1) calls. Cases (study patients), defined as Priority 1 transports with RTs exceeding 10:59 minutes, were compared with controls, which comprised a random sample of Priority 1 calls with RTs of 10:59 minutes or less. Prehospital run reports and hospital outcomes were evaluated using explicit criteria by one observer for the primary outcome of in-hospital death and secondary outcomes of critical interventions performed in the field. We tested the hypothesis of equivalence using the 95% confidence intervals (CIs) for difference in proportions with α = 0.05 and β = 0.2 to show Δ = ± 5%. Results. Of the 3,270 emergency transports in 2004, we identified 373 study patients (RT > 10:59 min) and a random sample of 373 controls (RT ≤ 10:59 min). Survival to hospital discharge was 80% (76% to 84%) for study patients vs. 82% (77% to 85%) for controls, yielding a 95% CI for the difference of –6 to +4%. ALS procedures were performed in 47.7% (95% CI: 43% to 53%) of study patients vs. 45.4% (40% to 51%) of controls (95% difference in proportions –10 to +5%). The most frequently performed procedures were administration of nitroglycerine and endotracheal intubation. Conclusions. Compared with patients who wait 10:59 minutes or less for ALS response, Priority 1 patients who wait longer than 10:59 minutes could experience between a 6% increase and a 4% decrease in mortality, and do not have an increase in critical procedures performed in the field. Our data are most consistent with the inference that neither the mortality nor the frequency of critical procedural interventions varies substantially based on this prespecified ALS RT.

Spinal immobilization in the field: clinical clearance criteria and implementation.

Awareness of the health and financial repercussions of unnecessary immobilization has made cervical spinal immobilization controversial in out-of-hospital care. Clinical criteria for clearance of the cervical spine in the hospital based on mechanism of injury have been supported by many trauma centers. However, implementation of clinical criteria for cervical spinal clearance in out-of-hospital settings is not as well validated by multicenter studies or accepted by many emergency departments. This consensus group recommends that clinical criteria to determine “low-risk” patients be available for use by emergency medical services providers in out-of-hospital settings; however, training, audits, quality management, integration into the medical community, and extent of program implementation should be decided based on individual emergency medical services systems.

Comparison of First-Attempt Success Between Tibial and Humeral Intraosseous Insertions During Out-of-Hospital Cardiac Arrest

Abstract Background. Intraosseous (IO) needle insertion is often utilized in the adult population for critical resuscitation purposes. Standard insertion sites include the proximal humerus and proximal tibia, for which limited comparison data are available. Objective. This study compared the frequencies of IO first-attempt success between humeral and tibial sites in out-of-hospital cardiac arrest. Methods. This observational study was conducted in an urban setting between August 28, 2009, and October 31, 2009, and included all medical cardiac arrest patients for whom resuscitative efforts were performed. Cardiac arrest protocols stipulate that paramedics insert an IO line for initial vascular access. During the first month of the study, the proximal humerus was the preferred primary insertion site, whereas the tibia was preferred throughout the second month. The primary outcome was first-attempt success, defined as secure IO needle position in the marrow cavity and normal fluid flow. Any needle dislodgment during resuscitation was also recorded. The association between first-attempt IO success and initial IO insertion location was analyzed using a test of independent proportions and 95% confidence intervals (CIs) for the difference in proportions. Results. There were 88 cardiac arrest patients receiving IO placement, with 58 (65.9%) patients receiving their initial IO attempt in the tibia. The rate of first-time IO success at the tibia was significantly higher than that observed at the humerus (89.7% vs. 60.0%; p < 0.01). There were 18 initial successes at the humerus; for six (33.3%) of these, the needle became dislodged during resuscitation, compared with 52 initial successes at the tibia, with three (5.8%) dislodgments. The rate of total success for initial IO placements was significantly lower for the humerus (40.0%) compared with that for the tibia (84.5%; p < 0.01) during resuscitation efforts. Conclusions. In this subset of patients, tibial IO needle placement appeared to be a more effective insertion site than the proximal humerus. Success rates were higher with a lower incidence of needle dislodgments. Further randomized studies are required in order to validate these results.