Lawrence M. Lewis

Controlled Trial of a Geriatric Case-Finding and Liaison Service in an Emergency Department

OBJECTIVE: To evaluate the effects of a program of case‐finding and liaison service for older patients visiting the emergency department.

Flexion-extension views in the evaluation of cervical-spine injuries

STUDY OBJECTIVE To determine the efficacy of flexion-extension (F/E) cervical-spine radiographs in detecting acute cervical-spine instability in emergency patients. DESIGN We retrospectively reviewed the charts of 141 consecutive trauma patients who had F/E views performed after a routine cervical-spine series (three views) was obtained in the emergency department. Interpretations of the routine series were compared with those of the F/E views to determine if additional useful information was provided by the latter. The charts also were reviewed to determine if any variables were associated with an increased use of F/E views, an increased likelihood of these views demonstrating instability, or any neurologic sequelae resulted from these studies. SETTING An urban Level I adult trauma center. MEASUREMENTS The interpretations of the routine series were noted to be either normal, abnormal but without demonstrable fracture/dislocation, or demonstrating a fracture/dislocation. The F/E views were categorized as stable, unstable, or uninterpretable. RESULTS Cervical-spine instability was demonstrated by F/E views in 11 of the 141 patients (8%), four of whom had normal routine cervical-spine films. Three of these four patients required surgical stabilization. Prolonged neck pain (more than 24 hours), an initially abnormal spine series, and a neurosurgical consult were all associated with an increased use of F/E views. Ten of 11 patients with radiographic instability had significant neck pain by history; the remaining patient was intoxicated. No neurologic sequelae resulted from performing F/E studies. There was one false-negative F/E study, which raises concern about the reliability of this procedure in the ED. CONCLUSION We believe that a large prospective study is required to determine which patients warrant F/E views.

Correlation of end-tidal CO2 to cerebral perfusion during CPR.

STUDY OBJECTIVE A number of studies have demonstrated a correlation between end-tidal carbon dioxide (ETCO2), cardiac output, and return of spontaneous circulation in experimental animals and in patients undergoing closed-chest CPR. Our study attempted to correlate ETCO2 to cerebral blood flow during cardiac arrest. DESIGN Sixteen piglets were anesthetized, intubated, and instrumented for cerebral blood flow studies. An ultrasonic flow probe was placed on both internal carotid arteries for continuous flow measurements. The animal was fibrillated, and closed-chest CPR was begun. Continuous ETCO2 measurements were obtained and compared with simultaneous internal carotid, cardiac output, and cerebral blood flow measurements. MEASUREMENTS AND MAIN RESULTS Correlations between ETCO2 and carotid and cerebral blood flow were determined using Pearsons method. The correlation between ETCO2 and total internal carotid flow was .58 (P = .01, Bonferronis adjusted P = .30). Correlation between ETCO2 and cerebral blood flow was .64 (P = .01, Bonferronis adjusted P = .09). A partial correlation coefficient for ETCO2 versus cardiac output was .70, whereas it was only .30 for ETCO2 versus cerebral blood flow. CONCLUSION Partial correlation coefficients suggest that ETCO2 correlates with cerebral blood flow when changes in cerebral blood flow parallel changes in cardiac output.

Do Wrist Guards Protect Against Fractures

STUDY OBJECTIVE To determine whether wrist guards increase the fracture threshold for wrist and forearm fractures. METHODS We conducted a controlled, blinded experimental study using matched cadaveric arms-one fitted with a wrist guard-dropped with the use of a device designed to simulate a fall. We measured the mean number of drops before the occurrence of fracture, mean height and velocity change to fracture, mean kinetic energy, mean peak acceleration (in Gs), and summed impulse [weight (kilograms) x delta velocity (meters/second)] to fracture with and without wrist guards. Fracture severity was compared with the use of an ordinal ranking system and analyzed with the Mann-Whitney rank-sum test. RESULTS Wrist guards were associated with a statistically significant increase in the number of drops, mean drop height, mean kinetic energy, and summed impulse required to cause a fracture. Fractures also tended to be less severe when wrist guards were used. CONCLUSION The biomechanical evidence of a protective effect of wrist guards against wrist fractures seen in this study, coupled with previous epidemiologic evidence, is strong enough to warrant pediatricians, family practitioners, and emergency physicians to counsel skaters to use these devices when using roller skates, skateboards, or in-line skates.

A noninvasive method for monitoring cerebral perfusion during cardiopulmonary resuscitation

PURPOSE This study evaluates the use of transcranial Doppler (TCD) ultrasound in assessing the changes experienced by the cerebral circulation during cardiopulmonary resuscitation (CPR) and compares it with measurements of internal carotid artery (ICA) flow rates (ultrasonic flow-meter measurements) and cerebral blood flow (CBF) (radioactive-microsphere measurements) in a porcine cardiac arrest model undergoing closed chest CPR. METHODS Sixteen piglets were anesthetized and subjected to TCD monitoring, ICA flow-rate measurements, and CBF measurements during CPR following induction of ventricular fibrillation. A total of 14 comparisons between TCD and CBF measurements, and 36 comparisons between TCD and ICA flow measurements were performed. Correlations were determined using Pearsons method, and the validity of the correlation was determined using Bonferonis adjusted probabilities. RESULTS The correlation between mean cerebral blood flow velocity and mean total ICA flow rate was 0.67 (P < .01). The correlation between peak systolic blood flow velocity and CBF was 0.76 (P = .02). CONCLUSIONS TCD can provide on-line information about cerebral perfusion during CPR.

Transcranial Doppler determination of cerebral perfusion in patients undergoing CPR: Methodology and preliminary findings

STUDY OBJECTIVES To correlate cerebral arterial blood velocity measurements as determined by transcranial Doppler ultrasound with various resuscitation maneuvers performed in an uncontrolled manner in a series of cardiac arrest patients undergoing standard resuscitation. TYPE OF PARTICIPANTS Any patient undergoing resuscitation for a nontraumatic cardiac arrest was eligible for the study. INTERVENTIONS Resuscitation was carried out while flow velocities were monitored in various intracranial arteries by transcranial Doppler ultrasound. Vessel identification was based on the angle and depth of insonation. MEASUREMENTS AND MAIN RESULTS The internal carotid artery was located more consistently than either middle cerebral or ophthalmic arteries and provided superior waveforms for analysis. Alterations in flow velocity were noted and correlated to various therapeutic interventions. Flow velocities were 70% of normal during the early phase of resuscitation but deteriorated over time until there was no evidence of net forward flow. Even early in CPR, flow was demonstrated only during systole. CONCLUSION Transcranial Doppler ultrasound appears to be a potentially promising means of determining cerebral flow in patients undergoing CPR.

A comparison of transcranial doppler ultrasound (TCD) and radioactive microspheres in determining cerebral perfusion in normal and low flow states

We have previously utilized the technique of transcranial Doppler (TCD) ultrasound to determine cerebral perfusion in patients undergoing cardiopulmonary resuscitation (CPR). In order to assess if TCD can reliably measure alterations in cerebral perfusion under conditions of normal and low cardiac outputs, we compared TCD measured blood flow velocities in the middle cerebral artery (MCA) of six piglets with radioactive microsphere determinations of total cerebral perfusion at baseline normal sinus rhythm (NSR), during CPR, and following return of spontaneous circulation (ROSC). Peak systolic and mean blood flow velocities were compared to the microsphere perfusion results on 15 different occasions; six during NSR, five during CPR, and four following ROSC. Although qualitative alterations in TCD measurements reflected changes in microsphere perfusion, we could not find a statistically significant correlation between either peak systolic or mean MCA blood flow velocities and microsphere perfusion measurements either overall or in any subgroup. The possible reasons which may explain the findings are discussed.

Tissue and organ procurement in the emergency department setting

A retrospective chart review of all emergency department (ED) deaths in patients younger than 65 years in seven area hospitals was performed for the calendar year of 1990. The number and percentage of families approached and consenting to tissue donation among the various EDs was compared and reasons for not approaching families were evaluated for their validity. Procurement rates between the years 1990 and 1991 were compared for two area hospitals, which made a specified (nonmedical) service responsible for tissue requests in 1991. There were 368 deaths, 255 of which were potential donors by acceptable criteria. Only 109 (43%) families were approached regarding tissue donation. The overall procurement rate was 12%. Suburban EDs had a higher approach and procurement rate than did urban EDs (49% vs 36%; P < .05 and 19% vs 5%; P < .01, respectively). Procurement rates for two hospitals that designated a specific procurement service in 1991 more than doubled (5% vs 11%; P = NS). Tissue procurement rates in EDs with procurement systems in place are low despite consent rates of those approached of 36%. The major contributing factor is the failure to request tissue from the families of eligible candidates even when there are no exclusion criteria met. Suburban EDs had a higher success rate than urban EDs.

Multiple aortic tears treated by primary suture repair

Blunt trauma to the chest with aortic tear is not an unusual sequela of rapid deceleration. Multiple aortic tears in a viable patient are unusual. A case is reported where multiple aortic lacerations were repaired without the use of prosthetic material. The use of a primary suture repair of aortic injuries is advocated for simple aortic tears not extending proximally to the arch whether they be single or multiple.

Transcranial Doppler Assessment of the Cerebral Hemodynamic Effect of Cardiopulmonary Resuscitation in Fatal Cardiac Arrest

The intracranial circulation of 22 patients who had nontraumatic fatal cardiac arrest was monitored using transcranial Doppler (TCD) ultrasound during cardiopulmonary resuscitation (CPR). The internal carotid artery (ICA) was most easily accessible with the least amount of artifact. The duration of the cardiac arrests varied from 6 to 70 minutes (mean, 63), and the TCD‐monitoring time from 1 to 33 minutes (mean, 9). Maximal ICA mean velocities obtained during CPR ranged between 8 and 66 cmjsec (mean, 38) while minimal mean velocities varied between 2 and 22 cmjsec (mean, 12). Although 3 patients developed spontaneous cardiac rhythm during TCD monitoring, all died. Minute‐to‐minute comparison of ICA mean velocities obtained during the last 1 0 minutes of arrest monitoring showed a statistically significant difference following a deeremental trend (p = 0.05). In patients undergoing CPR, cerebral blood flow velocities as measured by TCD decrease progressively. In addition, changes in Doppler waveform suggest this decrease is secondary to progressively increased flow resistance. The clinical and prognostic significance of these findings awaits definition.