Howard Werman - Academia.edu (original) (raw)

Papers by Howard Werman

Air Medical Journal, 2014

Resuscitation, 1986

Epinephrine in larger doses than currently recommended during cardiopulmonary resuscitation (CPR)... more Epinephrine in larger doses than currently recommended during cardiopulmonary resuscitation (CPR) has been shown to improve cerebral blood flow (CBF) following a 10-min arrest in a swine model. The purpose of this pilot study was to measure CBF during CPR, comparing high-dose epinephrine to a pure alpha-1 agonist, phenylephrine. Ten swine each weighing greater than 15 kg, were instrumented for regional CBF measurements using tracer microspheres. CBF was measured during normal sinus rhythm (NSR). Following 10 min of ventricular fibrillation, CPR was begun and regional CBF was again measured. Following 3 min of CPR, the swine were randomized to receive either epinephrine (0.2 mg/kg), or phenylephrine (0.1 mg/kg), through a peripheral intravenous line. Regional CBF was again measured 1 min after drug administration. Regional CBF following drug administration was compared using an analysis of covariance. Adjusted CBFs are expressed in ml/min per 100 g for epinephrine and phenylephrine, respectively: left cerebral cortex (12.5 vs. 2.3, P = 0.002); right cerebral cortex (13.0 vs. 2.8, P = 0.003); cerebellum (32.9 vs. 4.1, P = 0.004); midbrain (35.7 vs. 2.6, P = 0.0004), pons (30.3 vs. 2.9, P = O.006); medulla (49.5 vs. 13.6, P = 0.02) and cervical spinal cord (49.6 vs. 14.1, P = 0.003).

Prehospital and Disaster Medicine, 2011

The geriatric population is unique in the type of traumatic injuries sustained, physiological res... more The geriatric population is unique in the type of traumatic injuries sustained, physiological responses to those injuries, and an overall higher mortality when compared to younger adults. No published, evidence-based, geriatric-specific field destination criteria exist as part of a statewide trauma system. The Trauma Committee of the Ohio Emergency Medical Services (EMS) Board sought to develop specific criteria for geriatric trauma victims. A literature search was conducted for all relevant literature to determine potential, geriatric-specific, field-destination criteria. Data from the Ohio Trauma Registry were used to compare elderly patients, defined as age >70 years, to all patients between the ages of 16 to 69 years with regards to mortality risk in the following areas: (1) Glasgow Coma Scale (GCS) score; (2) systolic blood pressure (SBP); (3) falls associated with head, chest, abdominal or spinal injury; (4) mechanism of injury; (5) involvement of more than one body system as defined in the Barell matrix; and (6) co-morbidities and motor vehicle collision with one or more long bone fracture. For GCS score and SBP, those cut-off points with equal or greater risk of mortality as compared to current values were chosen as proposed triage criteria. For other measures, any criterion demonstrating a statistically significant increase in mortality risk was included in the proposed criteria. The following criteria were identified as geriatric-specific criteria: (1) GCS score <14 in the presence of known or suspected traumatic brain trauma; (2) SBP <100 mmHg; (3) fall from any height with evidence of traumatic brain injury: (4) multiple body-system injuries; (5) struck by a moving vehicle; and (6) the presence of any proximal long bone fracture following motor vehicle trauma. In addition, these data suggested that elderly patients with specific co-morbidities be given strong consideration for evaluation in a trauma center. The state of Ohio is the first state to develop evidence-based geriatric-specific field-destination criteria using data from its state-mandated trauma registry. Further analysis of these criteria will help determine their effects on over-triage and under-triage of geriatric victims of traumatic injuries and the impact on the overall mortality in the elderly.

The Journal of Emergency Medicine, 2013

Compartment syndrome is a limb-threatening complication associated with extremity trauma. The exi... more Compartment syndrome is a limb-threatening complication associated with extremity trauma. The existence of compartment syndrome involving the thenar space is considered controversial and has not been reported in association with blunt traumatic injury of the hand. We report two cases involving compartment syndrome of the thenar space in association with blunt trauma to the hand. Patient A was a young man who suffered a fracture/dislocation of the right thumb after a fall. Compartment pressures were measured at 70 mm Hg in the thenar space. The patient underwent successful fasciotomy and K-wire stabilization of the thumb and was ultimately discharged with good function on day 4. Patient B suffered a crush injury of the right hand and presented with diffuse swelling associated with median nerve paresthesia. Radiographs revealed a fracture of the triquetrum and of the base of the third metacarpal bone. The patient underwent multiple fasciotomies of the hand, including a release of the thenar space. He was discharged on day 2 with improving function of his thumb. Compartment syndrome of the thenar space may be more common than previously reported. Given the limited time frame after which permanent damage occurs, clinicians should consider measurement of thenar compartment pressures in high-risk injuries.

IEEE Transactions on Biomedical Engineering, 1990

Recent studies have suggested that the initial therapeutic intervention for ventricular fibrillat... more Recent studies have suggested that the initial therapeutic intervention for ventricular fibrillation (VF) may depend on downtime (DT), i.e., the time duration of VF. We characterized the dynamics of the frequency distribution in the power spectrum of the ECG recorded from eleven swine during VF to determine if enough information existed in this domain to estimate DT. We used the median frequency (FM) of the power spectrum to track the frequency distribution. The FM followed a dynamic repeatable course during the first 10 min of VF. Intersubject variability was small. We modeled the FM data of the eleven sub.jects with a set of first-order polynomial equations and tested the algorithm with data from an additional ten subjects. The algorithm predicted VF duration with an average error of -0.86 min; 71.5% of the predictions fell within the 95% confidence limits of the model. This paper has identified a signal processing tool which may be useful in the prehospital treatment of VF.

Critical Care Medicine, 1989

Direct mechanical ventricular assistance (DMVA) is a method of biventricular circulatory support ... more Direct mechanical ventricular assistance (DMVA) is a method of biventricular circulatory support that employs a pneumatic device to apply both systolic and diastolic forces directly to the ventricular myocardium. This study investigated the effects of DMVA on myocardial hemodynamics when applied after a prolonged cardiopulmonary arrest. Seven swine weighting 28.3 +/- 2.5 kg were instrumented for regional myocardial blood flow (MBF) measurements using tracer microspheres. Ventricular fibrillation was then induced. After 10 min of ventricular fibrillation, CPR was initiated for 3 min. DMVA was then applied through median sternotomy. Defibrillation was attempted after 3.5 min of DMVA. If unsuccessful, DMVA was instituted for another 17.5 min and a subsequent defibrillation attempt was made. Arterial oxygen content (CaO2), coronary sinus oxygen content (CcSO2), myocardial oxygen delivery/consumption (mDO2/mVO2), extraction ratio (ER), and endocardial/epicardial blood flow ratio (EN/EP) were determined during CPR, during the initial application of DMVA (DMVA1), and after the subsequent 17.5 min of DMVA in those animals not initially defibrillated (DMVA2). Three of the seven animals were successfully defibrillated during DMVA1. After the additional 17.5 min of DMVA, only one other animal was defibrillated. There was a significant improvement in CaO2, CcSO2, MBF, mDO2, mVO2, ER, and EN/EP after DMVA1 compared to CPR. Only mVO2 and ER improved significantly after DMVA2. These findings support the concept that physical diastolic augmentation may improve myocardial hemodynamics when DMVA is applied during cardiac arrest.

Critical Care Medicine, 1987

Annals of Emergency Medicine, 1989

As the duration of time between the onset of ventricular fibrillation and the application of defi... more As the duration of time between the onset of ventricular fibrillation and the application of defibrillation (downtime) increases, the rate of successful resuscitation decreases. Results of recent animal studies suggest that the rate of successful resuscitation may be increased after a prolonged cardiorespiratory arrest when pharmacologic therapy is instituted before defibrillation. An accurate estimation of downtime could be critical in selecting the most appropriate therapeutic intervention. The purpose of our study was to determine whether changes in the frequency or amplitude of the ventricular fibrillation ECG signal during cardiac arrest could be used to estimate downtime. We characterized the dynamics of both total power and frequency distribution of the power in the ECG during ventricular fibrillation in 1I swine to determine whether enough information existed in either parameter to estimate downtime. The median frequency of the power spectrum was used to track power distribution. Both parameters followed a dynamic, repeatable pattern. However, median frequency showed less intersubject variability than did total power. A mathematical model of median frequency was developed and used with data obtained from ten additional swine to estimate downtime. The model estimated downtime to within 1.3 minutes of actual downtime between one and ten minutes of ventricular fibrillation. Our study has identified a new, potentially useful parameter for studying various management strategies in ventricular fibrillation as a function

Annals of Emergency Medicine, 1988

The improvement in cerebral blood flow (CBF) during CPR after epinephrine administration has been... more The improvement in cerebral blood flow (CBF) during CPR after epinephrine administration has been attributed to epinephrine's alpha-adrenergic properties. Methoxamine, a pure alpha-1 agonist, has only been shown to be comparable to epinephrine in restoring circulation after cardiac arrest in a canine model. This study compares the effectiveness of equipotent doses of epinephrine and methoxamine in improving CBF during CPR after a prolonged cardiac arrest in a swine model. Twenty-five swine, weighing 15.9 to 28.2 kg, underwent instrumentation for regional CBF using tracer microspheres. CBF was determined during normal sinus rhythm. After 10 min of ventricular fibrillation, CPR was begun with a pneumatic compressor. CBF measurements were again made during CPR. After 3 min of CPR, the swine were randomized to receive 0.02 or 0.2 mg/kg epinephrine, 0.1, 1.0, or 10.0 mg/kg methoxamine. Five swine were allocated to each group. CBF measurements were determined after drug administration and compared using a Bonferroni multiple comparison procedure. A p-value less than .05 was considered statistically significant. This study demonstrated that, after a 10-min cardiac arrest, CBF was extremely low, averaging less than 7 ml/min X 100 g during external CPR. There were no clinically significant improvements in regional CBF after 0.02 mg/kg of epinephrine, or the two lowest doses of methoxamine. The addition of 10 mg/kg of methoxamine clinically improved blood flow only to the most caudal CNS structures, including the pons, medulla, and cervical spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)

Annals of Emergency Medicine, 1989

Several clinical studies have yielded conflicting results in examining the effectiveness of bysta... more Several clinical studies have yielded conflicting results in examining the effectiveness of bystander CPR (BCPR). The purpose of this pilot study was to determine the effectiveness of BCPR in an animal model of cardiac arrest and resuscitation. Ten swine were instrumented ,for hemodynamic and regional blood flow measurements with tracer microspheres. After two minutes of ventricular fibrillation (VF), the animals received eight minutes of either BCPR (five) or no-bystander CPR (NBCPR; five). Deftbrillation was then attempted in both groups. If unsuccessful, CPR was begun and epinephrine 0.02 mg/kg was administered. Defibrillation was attempted again three and one-haft minutes after epinephrine administration. Regional myocardial and cerebral blood flows were measured 30 seconds and five and one-half minutes after initiation of BCPR and one minute after epinephrine administration. In the BCPR group, myocardial blood flow was initially 29.0 +-33.2 and decreased to 15.0 +_ 21.5 mL/ min/lO0 g during the last two and one-half minutes of BCPR. Cortical cerebral blood flow was initially 2.0 + 2.8 and fell to 0.6 +_ 0.8 roll min/lO0 g during the last two and one-half minutes of BCPR. There were no statistical differences in myocardial blood flow and cerebral blood flow between the initial or late stages of BCPR (P > .14). There were no statistical differences in myocardial blood flow and cerebral blood flow between BCPR and NBCPR groups after epinephrine administration (P > .09). There were no successful resuscitations in either group before or after epinephrine administration. We conclude that BCPR is not effective at maintaining adequate myocardial blood flow or cerebral blood flow in this tenminute cardiac arrest model. Further study is needed to discern the effectiveness of BCPR in this model with shorter arrest durations. [Hoekstra JW, Rinnert K, Van Ligten P, Neumar R, Werman HA, Brown CG: The effectiveness of bystander CPR in an animal model.

Annals of Emergency Medicine, 1987

Prior studies have not found the alpha agonist phenylephrine, in a dose of 0.1 mg/kg, to be as ef... more Prior studies have not found the alpha agonist phenylephrine, in a dose of 0.1 mg/kg, to be as effective as 0.20 mg/kg of epinephrine in improving regional cerebral blood flow (CBF) during CPR in swine. We undertook this study to assess whether higher doses of phenylephrine might improve regional CBF. Fifteen swine were allocated to receive either epinephrine 0.2 mg/kg, phenylephrine 1.0 mg/kg, or phenylephrine 10 mg/kg. Regional CBF measurements were made during normal sinus rhythm, during CPR, and during CPR following drug administration. Epinephrine 0.2 mg/kg was significantly better in improving regional CBF to the left and right cerebral cortices, cerebellum, midbrain, and cervical cord than was phenylephrine 1.0 mg/kg. There was no significant difference in regional CBF between the animals receiving epinephrine 0.2 mg/kg and phenylephrine 10 mg/kg. The study shows that large doses of epinephrine and phenylephrine may be required during CPR to improve regional cerebral blood flow following a prolonged arrest.

Annals of Emergency Medicine, 1985

ABSTRACTS turn visit to the ED within 7 days. The treatment protocol was introduced in January 19... more ABSTRACTS turn visit to the ED within 7 days. The treatment protocol was introduced in January 1982. Treatment of the patient was and continued to be directed by the PGY1 and PGY2 housestaff. Although the protocol was stressed to the housestaff, strict direct supervision of its use was not possible. Charts were reviewed retrospectively to assess the impact of the treatment protocol. Results are shown in the table.

Annals of Emergency Medicine, 1986

Cerebral blood flow (CBF) with conventional closed-chest cardiopulmonary resuscitation (CCPR) has... more Cerebral blood flow (CBF) with conventional closed-chest cardiopulmonary resuscitation (CCPR) has been measured at only 2% to 11% of prearrest values. The purpose of our study was to determine whether the peripheral administration of higher doses of epinephrine than currently recommended during CCPR following a prolonged cardiac arrest improves CBF compared to CCPR using a standard dose of epinephrine. Fifteen swine were randomized to receive CCPR plus 0.02 mg/kg, 0.2 mg/kg, or 2.0 mg/kg epinephrine through a peripheral IV line following a ten-minute cardiopulmonary arrest and three minutes of CCPR. Regional CBF measurements were made by radionuclide microsphere technique during normal sinus rhythm (NSR), CCPR, and following epinephrine administration. The adjusted regional blood flows (in mL/min/100 g) following epinephrine administration for the 0.02-, 0.2-, and 2.0-mg/kg groups were, respectively, left cerebral cortex (3.3, 13.1, 11.8); right cerebral cortex (3.9, 13.8, 12.2); cerebellum (9.2, 32.0, 33.1); midbrain/pons (9.9, 32.1, 32.3); medulla (10.6, 61.5, 54.2); and cervical spinal cord (12.2, 53.8, 35.8). In this swine model, 0.2 mg/kg and 2.0 mg/kg epinephrine significantly increased regional CBF over that seen with standard doses. Because neuronal survival is dependent on flow rates of 10 to 15 mL/min/100 g, this preliminary evidence suggests that these higher doses of epinephrine may help improve neurological outcome in CCPR.

Annals of Emergency Medicine, 1988

Our study compared the effect of high-dose epinephrine with the pure alphaagonist phenylephrine o... more Our study compared the effect of high-dose epinephrine with the pure alphaagonist phenylephrine on regional myocardial blood flow (MBF), myocardial oxygen delivery (MD02), myocardial oxygen consumption (MV02), and defibrillation rates during CPR. Fifteen swine weighing more than 15 kg were instrumented for measurement of regional MBF using radiolabeled tracer microspheres. Measurements of regional MBF, MD02, and MVO 2 were made during normal sinus rhythm. Ventricular fibrillation was induced and persisted for ten minutes. CPR was begun using a pneumatic compression device. Regional MBF, MD02, and MVO 2 were measured during CPR. Following three minutes of CPR, animals (N= 15) were allocated to one of three groups (n = 5): Group 1, epinephrine 0.2 mg/kg; Group 2, phenylephrine 0.1 mg/kg; or Group 3, phenylephrine 1.0 mg/kg. Measurements of regional MBF, MDO 2, and MVO 2 were repeated after drug administration. Extraction ratios, defined as MVOJMDO 2, were calculated during normal sinus rhythm, CPR, and after drug administration. Defibrillation was attempted 31/2 minutes after drug administration. There was no significant difference in MBE MDO 2, MVO 2, and extraction ratio during normal sinus rhythm and CPR for any of the groups. Total MBF following drug administration was 67.2 +_ 49.4 mL/min/lO0 g for the group receiving epinephrine 0.2 mg/kg; 7.0 ± 7.1 mL/min/IO0 g for the group receiving phenylephrine 0.I mg/kg; and 36.7 ± 21.1 mL/min/lO0 g for the group receiving phenylephrine 1.0 rag~ kg. The extraction ratios for animals receiving epinephrine 0.2 mg/kg, phenylephrine 0.1 rag~ g, and phenylephrine 1.0 mg/kg were 76.6 ± 10.5%, 94.6 ± 4.0%, and 90.7 + 7.5%, respectively. The extraction ratio for the group receiving epinephrine was significantly better than both phenylephrine groups (P = .01). Defibrillation rates for each group were 80%, 0%, and 0%, respectively. Our results suggest that epinephrine in doses higher than are currently recommended improves MBF and oxygen extraction ratios during CPR when compared with the pure alpha-agonist phenylephrine. /Brown CG, Taylor RB, Werman HA, Luu T, Ashton J, Hamlin RL: Myocardial oxygen delivery~consumption during cardiopulmonary resuscitation: A comparison of epinephrine and phenylephrine. Ann Emerg Med April 1988;17:302-308.]

The American Journal of Emergency Medicine, 1989

aAdrenergic drugs improve cerebral blood flow (CBF) during cardiopulmonary resuscltatlon (CPR), i... more aAdrenergic drugs improve cerebral blood flow (CBF) during cardiopulmonary resuscltatlon (CPR), in part, by reversing carotid artery collapse and by shunting blood from extracembral to lntracembral vascular structures. Admnergic drugs with 82. agonist pmpertles may cause peripheral vasodllatlon, and thus may be less beneflclal In thls setting. The purpose of this study was to compare eplnephrlne (E), an a,,*, 6,,,-agonlst, with noreplnephrlne (NE), an a1,2, 6,.agonist, on CBF during CPR. Twenty swine each weighing >15 kg were Instrumented for regional CBF measurements using tracer micmspheres. Regional CBF was measumd during normal sinus rhythm (NSR). Animals were then placed into ventricular fibrillation (VF). After ten minutes of VF, the animals received closed-chest CPR using a mechanical thumper. Regional CBF was measured during CPR. After three minutes of CPR, the animals were allocated to receive either E, 0.20 mg/kg (N = 5); NE, 0.08 mg/kg (N = 5); NE, 0.12 mp/kg (N = 5); or NE, 0.15 mg/kg (N = 5). Regional blood flows were again measured followlng drug administration. CBFs following drug administration were compared using an analysis of covariante adjusting for baseline differences during CPR. A Newman-Keuls multiple comparison was used to follow-up significant (P G .05) differences. Statistical slgnlflcance was consldemd at P G .05. Them was a clinically significant Improvement In cerebral cortical flow with NE, 0.12 mg/kg, and NE, 0.16 mg/kg, compamd with NE, 0.08 mg/kg. In general, them was no statistically slg-

The American Journal of Emergency Medicine, 1986

Recent studies in swine have demonstrated that larger doses of epinephrine (E) than those current... more Recent studies in swine have demonstrated that larger doses of epinephrine (E) than those currently employed for cardiopulmonary resuscitation (CPR), significantly improve regional myocardial blood flow (MBF) following a prolonged cardiac arrest. The dose response effect of a pure alpha adrenergic agonist, methoxamine (M), on regional MBF has not been investigated in this setting. The purpose of this study was to compare the effect of high dose epinephrine with graded doses of methoxamine on regional MBF during CPR.

The American Journal of Emergency Medicine, 1999

Air transport is commonly used to transfer survivors of cardiac arrest from rural hospitals to la... more Air transport is commonly used to transfer survivors of cardiac arrest from rural hospitals to large tertiary-care centers, presumably to improve outcome. To examine this issue, a retrospective review of patients stabilized after a cardiac arrest was conducted; 157 transports were reviewed. The mean age of patients was 37.9 -+ 27.8 yrs, with a male to female ratio of 2.2:1. Survivors were significantly older than nonsurvivors. Thirty-one of 69 patients (45%) with primary cardiac disease were discharged alive from the hospital, 75% without neurological sequelae. Only a minority of patients with noncardiac medical illness (7%), electrical injury (33%), suffocation (15%), near-drowning (15%), and inhalation (0%) were discharged alive from the hospital. Outcomes for cardiac arrest in adult patients older than 65 years (32.3%% survival) were similar to those for adult patients younger than 65 years (36.2% survival) (P = .887). These results show that survivors of a primary cardiac event have a favorable outcome when transferred by air to tertiary centers when compared with historical controls that were transported by ground. On the other hand, cardiac arrests from noncardiac medical illness, suffocation, near-drowning, and inhalation have a grim prognosis. Prospective studies should clarify the role of air transport in these patients. (Am J Emerg Med 1999;17:130-134.

Air Medical Journal, 1998

In a rural service area, does the

Air Medical Journal, 1996

Air Medical Journal, 1996

Air Medical Journal, 2014

Resuscitation, 1986

Epinephrine in larger doses than currently recommended during cardiopulmonary resuscitation (CPR)... more Epinephrine in larger doses than currently recommended during cardiopulmonary resuscitation (CPR) has been shown to improve cerebral blood flow (CBF) following a 10-min arrest in a swine model. The purpose of this pilot study was to measure CBF during CPR, comparing high-dose epinephrine to a pure alpha-1 agonist, phenylephrine. Ten swine each weighing greater than 15 kg, were instrumented for regional CBF measurements using tracer microspheres. CBF was measured during normal sinus rhythm (NSR). Following 10 min of ventricular fibrillation, CPR was begun and regional CBF was again measured. Following 3 min of CPR, the swine were randomized to receive either epinephrine (0.2 mg/kg), or phenylephrine (0.1 mg/kg), through a peripheral intravenous line. Regional CBF was again measured 1 min after drug administration. Regional CBF following drug administration was compared using an analysis of covariance. Adjusted CBFs are expressed in ml/min per 100 g for epinephrine and phenylephrine, respectively: left cerebral cortex (12.5 vs. 2.3, P = 0.002); right cerebral cortex (13.0 vs. 2.8, P = 0.003); cerebellum (32.9 vs. 4.1, P = 0.004); midbrain (35.7 vs. 2.6, P = 0.0004), pons (30.3 vs. 2.9, P = O.006); medulla (49.5 vs. 13.6, P = 0.02) and cervical spinal cord (49.6 vs. 14.1, P = 0.003).

Prehospital and Disaster Medicine, 2011

The geriatric population is unique in the type of traumatic injuries sustained, physiological res... more The geriatric population is unique in the type of traumatic injuries sustained, physiological responses to those injuries, and an overall higher mortality when compared to younger adults. No published, evidence-based, geriatric-specific field destination criteria exist as part of a statewide trauma system. The Trauma Committee of the Ohio Emergency Medical Services (EMS) Board sought to develop specific criteria for geriatric trauma victims. A literature search was conducted for all relevant literature to determine potential, geriatric-specific, field-destination criteria. Data from the Ohio Trauma Registry were used to compare elderly patients, defined as age >70 years, to all patients between the ages of 16 to 69 years with regards to mortality risk in the following areas: (1) Glasgow Coma Scale (GCS) score; (2) systolic blood pressure (SBP); (3) falls associated with head, chest, abdominal or spinal injury; (4) mechanism of injury; (5) involvement of more than one body system as defined in the Barell matrix; and (6) co-morbidities and motor vehicle collision with one or more long bone fracture. For GCS score and SBP, those cut-off points with equal or greater risk of mortality as compared to current values were chosen as proposed triage criteria. For other measures, any criterion demonstrating a statistically significant increase in mortality risk was included in the proposed criteria. The following criteria were identified as geriatric-specific criteria: (1) GCS score <14 in the presence of known or suspected traumatic brain trauma; (2) SBP <100 mmHg; (3) fall from any height with evidence of traumatic brain injury: (4) multiple body-system injuries; (5) struck by a moving vehicle; and (6) the presence of any proximal long bone fracture following motor vehicle trauma. In addition, these data suggested that elderly patients with specific co-morbidities be given strong consideration for evaluation in a trauma center. The state of Ohio is the first state to develop evidence-based geriatric-specific field-destination criteria using data from its state-mandated trauma registry. Further analysis of these criteria will help determine their effects on over-triage and under-triage of geriatric victims of traumatic injuries and the impact on the overall mortality in the elderly.

The Journal of Emergency Medicine, 2013

Compartment syndrome is a limb-threatening complication associated with extremity trauma. The exi... more Compartment syndrome is a limb-threatening complication associated with extremity trauma. The existence of compartment syndrome involving the thenar space is considered controversial and has not been reported in association with blunt traumatic injury of the hand. We report two cases involving compartment syndrome of the thenar space in association with blunt trauma to the hand. Patient A was a young man who suffered a fracture/dislocation of the right thumb after a fall. Compartment pressures were measured at 70 mm Hg in the thenar space. The patient underwent successful fasciotomy and K-wire stabilization of the thumb and was ultimately discharged with good function on day 4. Patient B suffered a crush injury of the right hand and presented with diffuse swelling associated with median nerve paresthesia. Radiographs revealed a fracture of the triquetrum and of the base of the third metacarpal bone. The patient underwent multiple fasciotomies of the hand, including a release of the thenar space. He was discharged on day 2 with improving function of his thumb. Compartment syndrome of the thenar space may be more common than previously reported. Given the limited time frame after which permanent damage occurs, clinicians should consider measurement of thenar compartment pressures in high-risk injuries.

IEEE Transactions on Biomedical Engineering, 1990

Recent studies have suggested that the initial therapeutic intervention for ventricular fibrillat... more Recent studies have suggested that the initial therapeutic intervention for ventricular fibrillation (VF) may depend on downtime (DT), i.e., the time duration of VF. We characterized the dynamics of the frequency distribution in the power spectrum of the ECG recorded from eleven swine during VF to determine if enough information existed in this domain to estimate DT. We used the median frequency (FM) of the power spectrum to track the frequency distribution. The FM followed a dynamic repeatable course during the first 10 min of VF. Intersubject variability was small. We modeled the FM data of the eleven sub.jects with a set of first-order polynomial equations and tested the algorithm with data from an additional ten subjects. The algorithm predicted VF duration with an average error of -0.86 min; 71.5% of the predictions fell within the 95% confidence limits of the model. This paper has identified a signal processing tool which may be useful in the prehospital treatment of VF.

Critical Care Medicine, 1989

Direct mechanical ventricular assistance (DMVA) is a method of biventricular circulatory support ... more Direct mechanical ventricular assistance (DMVA) is a method of biventricular circulatory support that employs a pneumatic device to apply both systolic and diastolic forces directly to the ventricular myocardium. This study investigated the effects of DMVA on myocardial hemodynamics when applied after a prolonged cardiopulmonary arrest. Seven swine weighting 28.3 +/- 2.5 kg were instrumented for regional myocardial blood flow (MBF) measurements using tracer microspheres. Ventricular fibrillation was then induced. After 10 min of ventricular fibrillation, CPR was initiated for 3 min. DMVA was then applied through median sternotomy. Defibrillation was attempted after 3.5 min of DMVA. If unsuccessful, DMVA was instituted for another 17.5 min and a subsequent defibrillation attempt was made. Arterial oxygen content (CaO2), coronary sinus oxygen content (CcSO2), myocardial oxygen delivery/consumption (mDO2/mVO2), extraction ratio (ER), and endocardial/epicardial blood flow ratio (EN/EP) were determined during CPR, during the initial application of DMVA (DMVA1), and after the subsequent 17.5 min of DMVA in those animals not initially defibrillated (DMVA2). Three of the seven animals were successfully defibrillated during DMVA1. After the additional 17.5 min of DMVA, only one other animal was defibrillated. There was a significant improvement in CaO2, CcSO2, MBF, mDO2, mVO2, ER, and EN/EP after DMVA1 compared to CPR. Only mVO2 and ER improved significantly after DMVA2. These findings support the concept that physical diastolic augmentation may improve myocardial hemodynamics when DMVA is applied during cardiac arrest.

Critical Care Medicine, 1987

Annals of Emergency Medicine, 1989

As the duration of time between the onset of ventricular fibrillation and the application of defi... more As the duration of time between the onset of ventricular fibrillation and the application of defibrillation (downtime) increases, the rate of successful resuscitation decreases. Results of recent animal studies suggest that the rate of successful resuscitation may be increased after a prolonged cardiorespiratory arrest when pharmacologic therapy is instituted before defibrillation. An accurate estimation of downtime could be critical in selecting the most appropriate therapeutic intervention. The purpose of our study was to determine whether changes in the frequency or amplitude of the ventricular fibrillation ECG signal during cardiac arrest could be used to estimate downtime. We characterized the dynamics of both total power and frequency distribution of the power in the ECG during ventricular fibrillation in 1I swine to determine whether enough information existed in either parameter to estimate downtime. The median frequency of the power spectrum was used to track power distribution. Both parameters followed a dynamic, repeatable pattern. However, median frequency showed less intersubject variability than did total power. A mathematical model of median frequency was developed and used with data obtained from ten additional swine to estimate downtime. The model estimated downtime to within 1.3 minutes of actual downtime between one and ten minutes of ventricular fibrillation. Our study has identified a new, potentially useful parameter for studying various management strategies in ventricular fibrillation as a function

Annals of Emergency Medicine, 1988

The improvement in cerebral blood flow (CBF) during CPR after epinephrine administration has been... more The improvement in cerebral blood flow (CBF) during CPR after epinephrine administration has been attributed to epinephrine's alpha-adrenergic properties. Methoxamine, a pure alpha-1 agonist, has only been shown to be comparable to epinephrine in restoring circulation after cardiac arrest in a canine model. This study compares the effectiveness of equipotent doses of epinephrine and methoxamine in improving CBF during CPR after a prolonged cardiac arrest in a swine model. Twenty-five swine, weighing 15.9 to 28.2 kg, underwent instrumentation for regional CBF using tracer microspheres. CBF was determined during normal sinus rhythm. After 10 min of ventricular fibrillation, CPR was begun with a pneumatic compressor. CBF measurements were again made during CPR. After 3 min of CPR, the swine were randomized to receive 0.02 or 0.2 mg/kg epinephrine, 0.1, 1.0, or 10.0 mg/kg methoxamine. Five swine were allocated to each group. CBF measurements were determined after drug administration and compared using a Bonferroni multiple comparison procedure. A p-value less than .05 was considered statistically significant. This study demonstrated that, after a 10-min cardiac arrest, CBF was extremely low, averaging less than 7 ml/min X 100 g during external CPR. There were no clinically significant improvements in regional CBF after 0.02 mg/kg of epinephrine, or the two lowest doses of methoxamine. The addition of 10 mg/kg of methoxamine clinically improved blood flow only to the most caudal CNS structures, including the pons, medulla, and cervical spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)

Annals of Emergency Medicine, 1989

Several clinical studies have yielded conflicting results in examining the effectiveness of bysta... more Several clinical studies have yielded conflicting results in examining the effectiveness of bystander CPR (BCPR). The purpose of this pilot study was to determine the effectiveness of BCPR in an animal model of cardiac arrest and resuscitation. Ten swine were instrumented ,for hemodynamic and regional blood flow measurements with tracer microspheres. After two minutes of ventricular fibrillation (VF), the animals received eight minutes of either BCPR (five) or no-bystander CPR (NBCPR; five). Deftbrillation was then attempted in both groups. If unsuccessful, CPR was begun and epinephrine 0.02 mg/kg was administered. Defibrillation was attempted again three and one-haft minutes after epinephrine administration. Regional myocardial and cerebral blood flows were measured 30 seconds and five and one-half minutes after initiation of BCPR and one minute after epinephrine administration. In the BCPR group, myocardial blood flow was initially 29.0 +-33.2 and decreased to 15.0 +_ 21.5 mL/ min/lO0 g during the last two and one-half minutes of BCPR. Cortical cerebral blood flow was initially 2.0 + 2.8 and fell to 0.6 +_ 0.8 roll min/lO0 g during the last two and one-half minutes of BCPR. There were no statistical differences in myocardial blood flow and cerebral blood flow between the initial or late stages of BCPR (P > .14). There were no statistical differences in myocardial blood flow and cerebral blood flow between BCPR and NBCPR groups after epinephrine administration (P > .09). There were no successful resuscitations in either group before or after epinephrine administration. We conclude that BCPR is not effective at maintaining adequate myocardial blood flow or cerebral blood flow in this tenminute cardiac arrest model. Further study is needed to discern the effectiveness of BCPR in this model with shorter arrest durations. [Hoekstra JW, Rinnert K, Van Ligten P, Neumar R, Werman HA, Brown CG: The effectiveness of bystander CPR in an animal model.

Annals of Emergency Medicine, 1987

Prior studies have not found the alpha agonist phenylephrine, in a dose of 0.1 mg/kg, to be as ef... more Prior studies have not found the alpha agonist phenylephrine, in a dose of 0.1 mg/kg, to be as effective as 0.20 mg/kg of epinephrine in improving regional cerebral blood flow (CBF) during CPR in swine. We undertook this study to assess whether higher doses of phenylephrine might improve regional CBF. Fifteen swine were allocated to receive either epinephrine 0.2 mg/kg, phenylephrine 1.0 mg/kg, or phenylephrine 10 mg/kg. Regional CBF measurements were made during normal sinus rhythm, during CPR, and during CPR following drug administration. Epinephrine 0.2 mg/kg was significantly better in improving regional CBF to the left and right cerebral cortices, cerebellum, midbrain, and cervical cord than was phenylephrine 1.0 mg/kg. There was no significant difference in regional CBF between the animals receiving epinephrine 0.2 mg/kg and phenylephrine 10 mg/kg. The study shows that large doses of epinephrine and phenylephrine may be required during CPR to improve regional cerebral blood flow following a prolonged arrest.

Annals of Emergency Medicine, 1985

ABSTRACTS turn visit to the ED within 7 days. The treatment protocol was introduced in January 19... more ABSTRACTS turn visit to the ED within 7 days. The treatment protocol was introduced in January 1982. Treatment of the patient was and continued to be directed by the PGY1 and PGY2 housestaff. Although the protocol was stressed to the housestaff, strict direct supervision of its use was not possible. Charts were reviewed retrospectively to assess the impact of the treatment protocol. Results are shown in the table.

Annals of Emergency Medicine, 1986

Cerebral blood flow (CBF) with conventional closed-chest cardiopulmonary resuscitation (CCPR) has... more Cerebral blood flow (CBF) with conventional closed-chest cardiopulmonary resuscitation (CCPR) has been measured at only 2% to 11% of prearrest values. The purpose of our study was to determine whether the peripheral administration of higher doses of epinephrine than currently recommended during CCPR following a prolonged cardiac arrest improves CBF compared to CCPR using a standard dose of epinephrine. Fifteen swine were randomized to receive CCPR plus 0.02 mg/kg, 0.2 mg/kg, or 2.0 mg/kg epinephrine through a peripheral IV line following a ten-minute cardiopulmonary arrest and three minutes of CCPR. Regional CBF measurements were made by radionuclide microsphere technique during normal sinus rhythm (NSR), CCPR, and following epinephrine administration. The adjusted regional blood flows (in mL/min/100 g) following epinephrine administration for the 0.02-, 0.2-, and 2.0-mg/kg groups were, respectively, left cerebral cortex (3.3, 13.1, 11.8); right cerebral cortex (3.9, 13.8, 12.2); cerebellum (9.2, 32.0, 33.1); midbrain/pons (9.9, 32.1, 32.3); medulla (10.6, 61.5, 54.2); and cervical spinal cord (12.2, 53.8, 35.8). In this swine model, 0.2 mg/kg and 2.0 mg/kg epinephrine significantly increased regional CBF over that seen with standard doses. Because neuronal survival is dependent on flow rates of 10 to 15 mL/min/100 g, this preliminary evidence suggests that these higher doses of epinephrine may help improve neurological outcome in CCPR.

Annals of Emergency Medicine, 1988

Our study compared the effect of high-dose epinephrine with the pure alphaagonist phenylephrine o... more Our study compared the effect of high-dose epinephrine with the pure alphaagonist phenylephrine on regional myocardial blood flow (MBF), myocardial oxygen delivery (MD02), myocardial oxygen consumption (MV02), and defibrillation rates during CPR. Fifteen swine weighing more than 15 kg were instrumented for measurement of regional MBF using radiolabeled tracer microspheres. Measurements of regional MBF, MD02, and MVO 2 were made during normal sinus rhythm. Ventricular fibrillation was induced and persisted for ten minutes. CPR was begun using a pneumatic compression device. Regional MBF, MD02, and MVO 2 were measured during CPR. Following three minutes of CPR, animals (N= 15) were allocated to one of three groups (n = 5): Group 1, epinephrine 0.2 mg/kg; Group 2, phenylephrine 0.1 mg/kg; or Group 3, phenylephrine 1.0 mg/kg. Measurements of regional MBF, MDO 2, and MVO 2 were repeated after drug administration. Extraction ratios, defined as MVOJMDO 2, were calculated during normal sinus rhythm, CPR, and after drug administration. Defibrillation was attempted 31/2 minutes after drug administration. There was no significant difference in MBE MDO 2, MVO 2, and extraction ratio during normal sinus rhythm and CPR for any of the groups. Total MBF following drug administration was 67.2 +_ 49.4 mL/min/lO0 g for the group receiving epinephrine 0.2 mg/kg; 7.0 ± 7.1 mL/min/IO0 g for the group receiving phenylephrine 0.I mg/kg; and 36.7 ± 21.1 mL/min/lO0 g for the group receiving phenylephrine 1.0 rag~ kg. The extraction ratios for animals receiving epinephrine 0.2 mg/kg, phenylephrine 0.1 rag~ g, and phenylephrine 1.0 mg/kg were 76.6 ± 10.5%, 94.6 ± 4.0%, and 90.7 + 7.5%, respectively. The extraction ratio for the group receiving epinephrine was significantly better than both phenylephrine groups (P = .01). Defibrillation rates for each group were 80%, 0%, and 0%, respectively. Our results suggest that epinephrine in doses higher than are currently recommended improves MBF and oxygen extraction ratios during CPR when compared with the pure alpha-agonist phenylephrine. /Brown CG, Taylor RB, Werman HA, Luu T, Ashton J, Hamlin RL: Myocardial oxygen delivery~consumption during cardiopulmonary resuscitation: A comparison of epinephrine and phenylephrine. Ann Emerg Med April 1988;17:302-308.]

The American Journal of Emergency Medicine, 1989

aAdrenergic drugs improve cerebral blood flow (CBF) during cardiopulmonary resuscltatlon (CPR), i... more aAdrenergic drugs improve cerebral blood flow (CBF) during cardiopulmonary resuscltatlon (CPR), in part, by reversing carotid artery collapse and by shunting blood from extracembral to lntracembral vascular structures. Admnergic drugs with 82. agonist pmpertles may cause peripheral vasodllatlon, and thus may be less beneflclal In thls setting. The purpose of this study was to compare eplnephrlne (E), an a,,*, 6,,,-agonlst, with noreplnephrlne (NE), an a1,2, 6,.agonist, on CBF during CPR. Twenty swine each weighing >15 kg were Instrumented for regional CBF measurements using tracer micmspheres. Regional CBF was measumd during normal sinus rhythm (NSR). Animals were then placed into ventricular fibrillation (VF). After ten minutes of VF, the animals received closed-chest CPR using a mechanical thumper. Regional CBF was measured during CPR. After three minutes of CPR, the animals were allocated to receive either E, 0.20 mg/kg (N = 5); NE, 0.08 mg/kg (N = 5); NE, 0.12 mp/kg (N = 5); or NE, 0.15 mg/kg (N = 5). Regional blood flows were again measured followlng drug administration. CBFs following drug administration were compared using an analysis of covariante adjusting for baseline differences during CPR. A Newman-Keuls multiple comparison was used to follow-up significant (P G .05) differences. Statistical slgnlflcance was consldemd at P G .05. Them was a clinically significant Improvement In cerebral cortical flow with NE, 0.12 mg/kg, and NE, 0.16 mg/kg, compamd with NE, 0.08 mg/kg. In general, them was no statistically slg-

The American Journal of Emergency Medicine, 1986

Recent studies in swine have demonstrated that larger doses of epinephrine (E) than those current... more Recent studies in swine have demonstrated that larger doses of epinephrine (E) than those currently employed for cardiopulmonary resuscitation (CPR), significantly improve regional myocardial blood flow (MBF) following a prolonged cardiac arrest. The dose response effect of a pure alpha adrenergic agonist, methoxamine (M), on regional MBF has not been investigated in this setting. The purpose of this study was to compare the effect of high dose epinephrine with graded doses of methoxamine on regional MBF during CPR.

The American Journal of Emergency Medicine, 1999

Air transport is commonly used to transfer survivors of cardiac arrest from rural hospitals to la... more Air transport is commonly used to transfer survivors of cardiac arrest from rural hospitals to large tertiary-care centers, presumably to improve outcome. To examine this issue, a retrospective review of patients stabilized after a cardiac arrest was conducted; 157 transports were reviewed. The mean age of patients was 37.9 -+ 27.8 yrs, with a male to female ratio of 2.2:1. Survivors were significantly older than nonsurvivors. Thirty-one of 69 patients (45%) with primary cardiac disease were discharged alive from the hospital, 75% without neurological sequelae. Only a minority of patients with noncardiac medical illness (7%), electrical injury (33%), suffocation (15%), near-drowning (15%), and inhalation (0%) were discharged alive from the hospital. Outcomes for cardiac arrest in adult patients older than 65 years (32.3%% survival) were similar to those for adult patients younger than 65 years (36.2% survival) (P = .887). These results show that survivors of a primary cardiac event have a favorable outcome when transferred by air to tertiary centers when compared with historical controls that were transported by ground. On the other hand, cardiac arrests from noncardiac medical illness, suffocation, near-drowning, and inhalation have a grim prognosis. Prospective studies should clarify the role of air transport in these patients. (Am J Emerg Med 1999;17:130-134.

Air Medical Journal, 1998

In a rural service area, does the

Air Medical Journal, 1996

Air Medical Journal, 1996