Biomedical subjects

Thomas H Blackwell

Publications and source records attributed to Thomas H Blackwell.

6 recordsLinked to original sources

PubMed2005

Transthoracic impedance does not affect defibrillation, resuscitation or survival in patients with out-of-hospital cardiac arrest treated with a non-escalating biphasic waveform defibrillator.

OBJECTIVE: This is a study of the influence of transthoracic impedance (TTI) on defibrillation, resuscitation and survival in patients with out-of-hospital cardiac arrest (OHCA), treated with a non-escalating impedance-compensating 150 J biphasic waveform defibrillator. METHODS: Cardiac arrest data from two EMS systems were analyzed retrospectively. All witnessed arrests from patients who presented with a shockable rhythm and were treated initially by BLS personnel were included (n = 102). For each defibrillation and resuscitation outcome variable, we tested differences in mean TTI for successful versus unsuccessful outcome. The effect of call-to-shock time on overall outcome was also examined. RESULTS: Initial shocks defibrillated 90% [83-95%] (95% confidence interval) of patients. Cumulative success with two shocks was 98% [93-100%] and with three shocks was 99% [95-100%]. TTI averaged 90 +/- 23 Omega. First-shock success, cumulative success through two shocks and cumulative success through the first-shock series were unrelated to TTI, as were BLS ROSC, pre-hospital ROSC, hospital admission and discharge. In contrast and consistent with previous findings, call-to-shock time was highly predictive of survival. CONCLUSIONS: High impedance patients were defibrillated by the biphasic waveform used in this study at high rates with a fixed energy of 150 J and without energy escalation. Rapid defibrillation rather than differences in patient impedance accounts for resuscitation success.

Cardiography, Impedance↗

PubMed2004

Body weight does not affect defibrillation, resuscitation, or survival in patients with out-of-hospital cardiac arrest treated with a nonescalating biphasic waveform defibrillator.

BACKGROUND: This is a study of the influence of body weight on defibrillation, resuscitation, and survival in patients with out-of-hospital cardiac arrest treated with a nonescalating impedance-compensating 150-J biphasic waveform defibrillator. METHODS: Cardiac arrest data from Rochester, MN, emergency medical services over a 6-yr period was retrospectively analyzed. Patient weight data were available for 62 of the 68 patients who were treated initially by basic life support personnel and who presented with a shockable rhythm. For each defibrillation and resuscitation outcome variable, we tested for differences in body weight for successful vs. unsuccessful outcome. RESULTS: Initial shocks defibrillated 92% (83% to 97%) of patients. Cumulative success with two shocks was 98% (confidence interval, 92% to 100%) and with three shocks was 100% (confidence interval, 95% to 100%). The mean shock impedance was 90 +/- 21 ohms. The average body weight was 84 +/- 17 kg (minimum, 53 kg; maximum, 135 kg) and was normally distributed. Based on the body mass index for 46 patients, approximately 41% were classified as overweight (body mass index, > or = 25), 24% obese (body mass index, > or = 30), and 4% extremely obese (body mass index, > or = 40). The remaining 31% were classified as normal or underweight. First-shock success, cumulative success through two shocks, and cumulative success through the first-shock series were unrelated to body weight, as were basic life support restoration of spontaneous circulation, prehospital restoration of spontaneous circulation, hospital admission, and discharge. CONCLUSIONS: Overweight patients were defibrillated by the biphasic waveform used in this study at high rates, with a fixed energy of 150 J, and without energy escalation.

Aged↗

PubMed2002

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.

Bioterrorism↗

PubMed2002

Interfacility transports.

Financial pressures exerted by managed care organizations toward hospitals to improve efficiencies and to lower total healthcare costs continue to force physicians and administrators to reevaluate operations and practices. This shifting of risk exposure from insurers to providers has resulted in many mergers, acquisitions, and affiliations, so as to form integrated health systems that reduce repetition and duplication of services. Therefore, as these integrated systems develop, along with the emergence of tertiary care, regional referral, and specialty hospitals, the need for patient transfers between such facilities will expand. The decision to move patients between facilities is a multicomponent process comprising health, safety, financial, and legal concerns. Interfacility transportation of patients has been performed over the past 20 to 30 years. Whereas ground transport services were prominent in the 1970s, air medical programs using helicopters and fixed-wing aircraft have recently become widespread. Both hospital-based and private agencies have continued to develop programs for efficiently and expeditiously transporting critically ill or injured patients, many requiring complex life-support devices. The Practice Management Committee of the American College of Emergency Physicians recently updated the 1990 policy statement on interfacility transfers, and two position statements are available from the National Association of EMS Physicians on criteria for air medical transport and medical direction for interfacility transport services. This review provides an overview of transportation systems and services available and assists physicians in understanding the various modes and characteristics of systems available. Personnel configurations and capabilities, physiological limitations, inherent requirements for equipment and patient preparation, and legal issues involved with transferring patients are also outlined.

Journal Article↗

PubMed2002

Response time effectiveness: comparison of response time and survival in an urban emergency medical services system.

UNLABELLED: Emergency medical services (EMS) administrators seek methods to enhance system performance. One component scrutinized is the response time (RT) interval between call receipt and arrival on scene. While reducing RTs may improve survival, this remains speculative and unreported. OBJECTIVE: To determine the effect of current RTs on survival in an urban EMS system. METHODS: The study was conducted in a metropolitan county (population 620,000). The EMS system is a single-tier, paramedic service and provides all service requests. The 90% fractile RT specifications required for county compliance include 10:59 minutes for emergency life-threatening calls (priority I) and 12:59 minutes for emergency non-life-threatening calls (priority II). All emergency responses resulting in a priority I or priority II transport to a Level 1 trauma center emergency department over a six-month period were evaluated to determine the relation between specified and arbitrarily assigned RTs and survival. RESULTS: Five thousand, four hundred twenty-four transports were reviewed. Of these, 71 patients did not survive (1.31%; 95% CI = 1.04% to 1.67%). No significant difference in median RTs between survivors (6.4 min) and nonsurvivors (6.8 min) was noted (p = 0.10). Further, there was no significant difference between observed and expected deaths (p = 0.14). However, mortality risk was 1.58% for patients whose RT exceeded 5 minutes, and 0.51% for those whose RT was under 5 minutes (p = 0.002). The mortality risk curve was generally flat over RT intervals exceeding 5 minutes. CONCLUSIONS: In this observational study, emergency calls where RTs were less than 5 minutes were associated with improved survival when compared with calls where RTs exceeded 5 minutes. While variables other than time may be associated with this improved survival, there is little evidence in these data to suggest that changing this system's response time specifications to times less than current, but greater than 5 minutes, would have any beneficial effect on survival.

Emergency Medical Services↗

PubMedDate not supplied

Linkages of acute care and EMS to state and local public health programs: application to public health programs.

Response to terrorism and mass casualty incidents has become a focal point for many public service agencies. Public health agencies and the emergency response community must work together to effectively and efficiently respond to any future incidents. Historically, collaboration has been a challenge since these agencies have functioned independently from one another, maintaining separate infrastructures that are not adequately interoperable. This article will summarize the consensus achieved during a meeting of multidisciplinary stakeholders held to discuss linkages between acute care, emergency medical services, and public health. The relevancy of these findings to public health, as well as the benefits from development of an interoperable infrastructure to public health, will be opined.

Bioterrorism↗