Chronic cerebral blood flow alterations in traumatic brain injury and sports-related concussions.

PRIMARY OBJECTIVE: Traumatic brain injury (TBI) and sports-related concussion (SRC) may result in chronic functional and neuroanatomical changes. We tested the hypothesis that neuroimaging findings (cerebral blood flow (CBF), cortical thickness, and 1H-magnetic resonance (MR) spectroscopy (MRS)) were associated to cognitive function, TBI severity, and sex. RESEARCH DESIGN: Eleven controls, 12 athletes symptomatic following ≥3SRCs and 6 patients with moderate-severe TBI underwent MR scanning for evaluation of cortical thickness, brain metabolites (MRS), and CBF using pseudo-continuous arterial spin labeling (ASL). Cognitive screening was performed using the RBANS cognitive test battery. MAIN OUTCOMES AND RESULTS: RBANS-index was impaired in both injury groups and correlated with the injury severity, although not with any neuroimaging parameter. Cortical thickness correlated with injury severity (p = 0.02), while neuronal density, using the MRS marker ((NAA+NAAG)/Cr, did not. On multivariate analysis, injury severity (p = 0.0003) and sex (p = 0.002) were associated with CBF. Patients with TBI had decreased gray (p = 0.02) and white matter (p = 0.02) CBF compared to controls. CBF was significantly lower in total gray, white matter and in 16 of the 20 gray matter brain regions in female but not male athletes when compared to female and male controls, respectively. CONCLUSIONS: Injury severity correlated with CBF, cognitive function, and cortical thickness. CBF also correlated with sex and was reduced in female, not male, athletes. Chronic CBF changes may contribute to the persistent injury mechanisms in TBI and rSRC.

Concussion incidence and recovery in Swedish elite soccer - Prolonged recovery in female players.

OBJECTIVES: Sport-related concussions are an increasingly recognized health problem. Soccer is the most popular sport in the world although recent studies on concussion incidence are scarce. Here, a nationwide prospective study on concussion incidence, symptom severity, risk factors, gender differences, and return-to-play after concussion was performed in 51 Swedish elite soccer teams during the 2017 season. METHODS: In the 1st and 2nd soccer leagues for men and women, a Sport Concussion Assessment Tool (SCAT)-based questionnaire study was performed at preseason (baseline) and from 48 hours to 3 months post-concussion. RESULTS: We followed 959 players (389 women, 570 men) for 25 146 player game hours (9867 hours for women, 15 279 hours for men). Concussion incidence (n = 36 concussions during the season) was 1.19/1000 player game hours (females 1.22/1000 hours, males 1.18/1000 hours; P = .85). Twenty-seven percent of all players (8% of females, 40% of males) continued to play immediately after the concussion. When compared to male players, female players had worse initial symptom severity scores (median and IQR 30 (17-50.5) vs 11 (4-26.25), P = .02) on SCAT and longer return-to-play (P = .02). Risk factors for concussion were baseline symptoms and previous concussion. CONCLUSION: In Swedish elite soccer, the concussion incidence was 1.19/1000 without gender differences. Most players recovered to play within 4 weeks post-injury. Almost one third of players continued to play at time of concussion. Female players had worse initial symptoms and longer return-to-play time than males, and a prolonged recovery beyond 3 months was only observed among female players.

Quality improvement in clinical teaching through student evaluations of rotations and feedback to departments.

BACKGROUND: Clinical teaching at medical schools needs continual improvement. We used a new evaluation instrument to gather student ratings on a departmental level across all clinical rotations. The ratings were used to enable cross comparison of departmental clinical teaching quality, official ranking and feedback as a method to improve teaching quality. This study was designed to evaluate whether these interventions increased the quality of clinical teaching. METHODS: A web-based questionnaire consisting of 10 questions (Likert scale 1-6) was introduced into all hospital departments at Uppsala University Hospital, Sweden. Specific feedback was given to participating departments based on the assessments collected. Action plans were created in order to address areas for departmental improvement. Questionnaire scores were used as a measure of clinical teaching quality. RESULTS: Mean follow-up time was 2.5 semesters. The student response rate was 70% (n = 1981). The departments' median ratings (25th-75th percentile) for the baseline were 4.05 (3.80-4.30). At follow-up, the median rating had increased to 4.56 (4.29-4.72) (p < 0.001). CONCLUSION: The introduction of a uniform clinical teaching evaluation instrument enabled cross comparison between clinical departments. Specific feedback enabled the development of action plans in the departments. This caused a rapid and substantial increase in the quality of clinical teaching.

Refined Analysis of Chronic White Matter Changes after Traumatic Brain Injury and Repeated Sports-Related Concussions: Of Use in Targeted Rehabilitative Approaches?

Traumatic brain injury (TBI) or repeated sport-related concussions (rSRC) may lead to long-term memory impairment. Diffusion tensor imaging (DTI) is helpful to reveal global white matter damage but may underestimate focal abnormalities. We investigated the distribution of post-injury regional white matter changes after TBI and rSRC. Six patients with moderate/severe TBI, and 12 athletes with rSRC were included ≥6 months post-injury, and 10 (age-matched) healthy controls (HC) were analyzed. The Repeatable Battery for the Assessment of Neuropsychological Status was performed at the time of DTI. Major white matter pathways were tracked using q-space diffeomorphic reconstruction and analyzed for global and regional changes with a controlled false discovery rate. TBI patients displayed multiple classic white matter injuries compared with HC (p < 0.01). At the regional white matter analysis, the left frontal aslant tract, anterior thalamic radiation, and the genu of the corpus callosum displayed focal changes in both groups compared with HC but with different trends. Both TBI and rSRC displayed worse memory performance compared with HC (p < 0.05). While global analysis of DTI-based parameters did not reveal common abnormalities in TBI and rSRC, abnormalities to the fronto-thalamic network were observed in both groups using regional analysis of the white matter pathways. These results may be valuable to tailor individualized rehabilitative approaches for post-injury cognitive impairment in both TBI and rSRC patients.

Tau aggregation and increased neuroinflammation in athletes after sports-related concussions and in traumatic brain injury patients - A PET/MR study.

Traumatic brain injury (TBI) and repeated sports-related concussions (rSRCs) are associated with an increased risk for neurodegeneration. Autopsy findings of selected cohorts of long-term TBI survivors and rSRC athletes reveal increased tau aggregation and a persistent neuroinflammation. To assess in vivo tau aggregation and neuroinflammation in young adult TBI and rSRC cohorts, we evaluated 9 healthy controls (mean age 26 ± 5 years; 4 males, 5 females), 12 symptomatic athletes (26 ± 7 years; 6 males, 6 females) attaining ≥3 previous SRCs, and 6 moderate-to severe TBI patients (27 ± 7 years; 4 males, 2 females) in a combined positron emission tomography (PET)/magnetic resonance (MR) scanner ≥6 months post-injury. Dual PET tracers, [18F]THK5317 for tau aggregation and [11C]PK11195 for neuroinflammation/microglial activation, were investigated on the same day. The Repeated Battery Assessment of Neurological Status (RBANS) scores, used for cognitive evaluation, were lower in both the rSRC and TBI groups (p < 0.05). Neurofilament-light (NF-L) levels were increased in plasma and cerebrospinal fluid (CSF; p < 0.05), and serum tau levels lower, in TBI although not in rSRC. In rSRC athletes, PET imaging showed increased neuroinflammation in the hippocampus and tau aggregation in the corpus callosum. In TBI patients, tau aggregation was observed in thalami, temporal white matter and midbrain; widespread neuroinflammation was found e.g. in temporal white matter, hippocampus and corpus callosum. In mixed-sex cohorts of young adult athletes with persistent post-concussion symptoms and in TBI patients, increased tau aggregation and neuroinflammation are observed at ≥6 months post-injury using PET. Studies with extended clinical follow-up, biomarker examinations and renewed PET imaging are needed to evaluate whether these findings progress to a neurodegenerative disorder or if spontaneous resolution is possible.

Soccer-Related Concussions Among Swedish Elite Soccer Players: A Descriptive Study of 1,030 Players.

Objective: There are growing concerns about the short- and long-term consequences of sports-related concussion, which account for about 5-9% of all sports injuries. We hypothesized there may be sex differences in concussion history and concussion-related symptoms, evaluated among elite soccer players in Sweden. Design: Retrospective survey study. Participants and Setting: Soccer players (n = 1,030) from 55 Swedish elite soccer teams. Questionnaires were completed prior to the start of the 2017 season. Assessment of Risk Factors: Player history of soccer-related concussion (SoRC), symptoms and management following a SoRC were evaluated. Main Outcome Measures: Before the start of the season the players completed a baseline questionnaire assessing previous concussions. The Sports Concussion Assessment Tool 3 was included with regard to symptom evaluation. Results: Out of 993 responding players 334 (34.6%) reported a previous SoRC and 103 players (10.4%) reported a SoRC during the past year. After sustaining a SoRC, 114 players (34.2%) reported that they continued their ongoing activity without a period of rest, more commonly female (44.9%) than male players (27.7%; P = 0.002). Symptom resolution time was 1 week or less for 61.3% of the players that reported having persisting symptoms. A positive correlation was observed between number of previous concussions and prevalence of three persisting symptoms: fatigue (P < 0.001), concentration/memory issues (P = 0.002) and headache (P = 0.047). Conclusion: About 35% of male and female elite soccer players in Sweden have experienced a previous SoRC, and about 10% experienced a SoRC during the last year. Female players continued to play after a SoRC, without a period of rest, more often than males. A higher risk of persisting symptoms was observed in players with a history of multiple concussions.

Smartphone-based evaluations of clinical placements-a useful complement to web-based evaluation tools.

PURPOSE: Web-based questionnaires are currently the standard method for course evaluations. The high rate of smartphone adoption in Sweden makes possible a range of new uses, including course evaluation. This study examines the potential advantages and disadvantages of using a smartphone app as a complement to web-based course evaluationsystems. METHODS: An iPhone app for course evaluations was developed and interfaced to an existing web-based tool. Evaluations submitted using the app were compared with those submitted using the web between August 2012 and June 2013, at the Faculty of Medicine at Uppsala University, Sweden. RESULTS: At the time of the study, 49% of the students were judged to own iPhones. Over the course of the study, 3,340 evaluations were submitted, of which 22.8% were submitted using the app. The median of mean scores in the submitted evaluations was 4.50 for the app (with an interquartile range of 3.70-5.20) and 4.60 (3.70-5.20) for the web (P=0.24). The proportion of evaluations that included a free-text comment was 50.5% for the app and 49.9% for the web (P=0.80). CONCLUSION: An app introduced as a complement to a web-based course evaluation system met with rapid adoption. We found no difference in the frequency of free-text comments or in the evaluation scores. Apps appear to be promising tools for course evaluations. web-based course evaluation system met with rapid adoption. We found no difference in the frequency of free-text comments or in the evaluation scores. Apps appear to be promising tools for course evaluations.

Vasopressin versus continuous adrenaline during experimental cardiopulmonary resuscitation.

OBJECTIVE: To evaluate the effects of a bolus dose of vasopressin compared to continuous adrenaline (epinephrine) infusion on vital organ blood flow during cardiopulmonary resuscitation (CPR). METHODS: Ventricular fibrillation was induced in 24 anaesthetised pigs. After a 5-min non-intervention interval, CPR was started. After 2 min of CPR the animals were randomly assigned to receive either vasopressin (0.4 U/kg) or adrenaline (bolus of 20 microg/kg followed by continuous infusion of 10 microg/(kg min)). Defibrillation was attempted after 9 min of CPR. RESULTS: Vasopressin generated higher cortical cerebral blood flow (P < 0.001) and lower cerebral oxygen extraction (P < 0.001) during CPR compared to continuous adrenaline. Coronary perfusion pressure during CPR was higher in vasopressin-treated pigs (P < 0.001) and successful resuscitation was achieved in 12/12 in the vasopressin group versus 5/12 in the adrenaline group (P = 0.005). CONCLUSIONS: In this experimental model, vasopressin caused a greater increase in cortical cerebral blood flow and lower cerebral oxygen extraction during CPR compared to continuous adrenaline. Furthermore, vasopressin generated higher coronary perfusion pressure and increased the likelihood of restoring spontaneous circulation.

Antithrombin reduction after experimental cardiopulmonary resuscitation.

OBJECTIVE: To determine whether activation of coagulation and inflammation during cardiac arrest results in a reduction of antithrombin (AT) and an increase in thrombin-antithrombin (TAT) complex during reperfusion. METHODS: Ventricular fibrillation (VF) was induced in ten anaesthetized pigs. After a 5-min non-intervention interval, closed-chest cardiopulmonary resuscitation (CPR) was performed for 9 min before defibrillation was attempted. If restoration of spontaneous circulation (ROSC) was achieved, the animals were observed for 4 h and repeated blood samples were taken for assay of AT, TAT and eicosanoids (8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha)). RESULTS: AT began to decrease 15 min after ROSC and the reduction continued throughout the observation period (P<0.05). The lowest mean value (79%) occurred 60 min after ROSC. The TAT level was increased during the first 3 h after ROSC (P<0.05), indicating thrombin generation. The eicosanoids were increased throughout the observation period (P<0.05). CONCLUSIONS: AT is reduced and TAT and eicosanoids are increased after cardiac arrest, indicating activation of coagulation and inflammation.

Antithrombin administration during experimental cardiopulmonary resuscitation.

OBJECTIVE: To determine whether antithrombin (AT) administration during cardiopulmonary resuscitation (CPR) increased cerebral circulation and reduced reperfusion injury. METHODS: Ventricular fibrillation was induced in 24 anaesthetised pigs. After a 5-min non-intervention interval, CPR was started. The animals were randomised into two groups. The treatment group received AT (250 U/kg) and the control group received placebo, after 7 min of CPR. Defibrillation was attempted after 9 min of CPR. If restoration of spontaneous circulation (ROSC) was achieved, the animals were observed for 4 h. Cortical cerebral blood flow was measured using laser-Doppler flowmetry. Cerebral oxygen extraction was calculated to reflect the relation between global cerebral circulation and oxygen demand. Measurements of eicosanoids (8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha)), AT, thrombin-antithrombin complex (TAT) and soluble fibrin in jugular bulb plasma were performed to detect any signs of cerebral oxidative injury, inflammation and coagulation. RESULTS: There was no difference between the groups in cortical cerebral blood flow, cerebral oxygen extraction, or levels of eicosanoids, TAT or soluble fibrin in jugular bulb plasma after ROSC. In the control group reduction of AT began 15 min after ROSC and continued throughout the entire observation period (P < 0.05). Eicosanoids and TAT were increased compared to baseline in all animals (P < 0.01). CONCLUSIONS: In this experimental model of CPR, AT administration did not increase cerebral circulation or reduce reperfusion injury after ROSC.

Increased cortical cerebral blood flow by continuous infusion of adrenaline (epinephrine) during experimental cardiopulmonary resuscitation.

OBJECTIVE: To study the effects of continuously administered adrenaline (epinephrine), compared to bolus doses, on the dynamics of cortical cerebral blood flow during experimental cardiopulmonary resuscitation (CPR), and after restoration of spontaneous circulation (ROSC). METHODS: Ventricular fibrillation was induced in 24 anaesthetised pigs. After a 5-min non-intervention interval, closed-chest CPR was started. The animals were randomised into two groups. One group received three boluses of adrenaline (20 microg/kg) at 3-min intervals. The other group received an initial bolus of adrenaline (20 microg/kg) followed by an infusion of adrenaline (10 microg/kg x min). After 9 min of CPR, defibrillation was attempted, and if spontaneous circulation was achieved the adrenaline infusion was stopped. Cortical cerebral blood flow was measured continuously using Laser-Doppler flowmetry. Jugular bulb oxygen saturation was measured to reflect global cerebral oxygenation. Repeated measurements of 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) in jugular bulb plasma were performed to evaluate cerebral oxidative injury. RESULTS: During CPR mean cortical cerebral blood flow was significantly higher (P=0.009) with a continuous adrenaline infusion than with repeated bolus doses. Following ROSC there was no significant difference in cortical cerebral blood flow between the two study groups. No differences in coronary perfusion pressure, rate of ROSC, jugular bulb oxygen saturation or 8-iso-PGF(2alpha) were seen between the study groups. CONCLUSIONS: Continuous infusion of adrenaline (10 microg/kg x min) generated a more sustained increase in cortical cerebral blood flow during CPR as compared to intermittent bolus doses (20 microg/kg every third minute). Thus, continuous infusion might be a more appropriate way to administer adrenaline as compared to bolus doses during CPR.

Cavoaortic shunt improves hemodynamics with preserved oxygen delivery in experimental right ventricular failure during left ventricular assist device therapy.

OBJECTIVE: Right heart failure is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. This study evaluated the approach of a cavoaortic shunt included in the LVAD circuit, which would aim to relieve venous congestion and improve hemodynamics with preserved oxygen delivery during induced right ventricular failure. METHODS: Right ventricular failure was induced by coronary ligation in 10 pigs. An LVAD was implanted and a cavoaortic shunt was created from the right atrium and included in the assist circuit. Hemodynamic measures and blood gas analyses were analyzed. Oxygen delivery and oxygen consumption were estimated. RESULTS: Right atrial pressure decreased from more than 20 mm Hg to 17.2 mm Hg (14.8-18.4) with the LVAD and to 14.1 mm Hg (11.2-15.5) (P < .01) with the LVAD and cavoaortic shunt. Mean arterial pressure increased from 70.9 mm Hg (67.6-79.8) to 81.5 mm Hg (70.8-92.6) (P = .02) with addition of the shunt into the assist circuit. Cardiac output increased from 3.5 L/min (2.6-4.2) to 4.9 L/min (3.5-5.6) (P < .01) with cavoaortic shunting. Oxygen delivery with the cavoaortic shunt was 337 mL/min (± 70) as compared with left ventricular assist alone at 258 mL/min (± 52) (P < .01). Oxygen consumption was restored during use of the cavoaortic shunt. CONCLUSIONS: A cavoaortic shunt combined with an LVAD during right ventricular failure reduces central venous pressures, increases systemic arterial pressure, and enables increased cardiac output compared with device therapy alone. This was feasible with preserved oxygen delivery.

A modified Glenn shunt improves haemodynamics in acute right ventricular failure in an experimental model.

OBJECTIVES: Right heart failure is a major cause of morbidity and mortality after left ventricular assist device implantation and is still hard to predict. This study investigated the haemodynamic effect of a modified Glenn shunt on induced right ventricular (RV) failure. METHODS: Isolated RV failure was induced by coronary ligation in 11 pigs. A modified Glenn shunt was established by a superior vena cava to pulmonary artery connection. Haemodynamic data were obtained at baseline, RV failure, and RV failure and open shunt. Myocardial biopsies were taken to ascertain established heart failure. RESULTS: RV failure defined as right atrial pressure ≥20 mmHg was achieved in all 11 animals. A reduction in cardiac output (CO) from 3.7 (3.5-4.2) to 2.3 l/min (2.0-2.6) and mean arterial pressure (MAP) from median 72.7 (70.1-82.2) to 55.9 mmHg (52.6-59.8) was seen during heart failure. The median flow in the shunt was 681 ml. Right atrial pressures decreased from 20.3 (19.6-21.1) to 13.4 mmHg (12.7-14.0), and RV pressures decreased from 18.1 (16.4-20.1) to 13.6 mmHg (13.5-14.2) with open shunt (P = 0.001 for both). CO increased to 2.9 l/min (2.4-3.3) when the shunt was in use. Mixed venous oxygen saturation increased with the shunt from 32 (27-38) to 49% (45-56), P = 0.001. Genes associated with heart failure were upregulated during heart failure. CONCLUSIONS: A modified Glenn shunt improved haemodynamics by reduced right atrial pressure, increased CO, MAP and mixed venous oxygen saturation in an experimental model of induced RV failure.

Prehospital trauma life support training of ambulance caregivers and the outcomes of traffic-injury victims in Sweden.

BACKGROUND: There is limited evidence that the widely implemented Prehospital Trauma Life Support (PHTLS) educational program improves patient outcomes. The primary aim of this national study in Sweden was to investigate the association between regional implementation of PHTLS training and mortality after traffic injuries. STUDY DESIGN: We extracted information from the Swedish National Patient Registry and the Cause of Death Registry on victims of motor-vehicle traffic injuries in Sweden from 2001 to 2004 (N = 28,041). During this time period, PHTLS training was implemented at a varying pace in different regions. To control for other influences on patient outcomes related to regional and hospital-level effects, such as variations in performance of trauma care systems, we used Bayesian hierarchical regression models to estimate odds ratios for prehospital mortality and 30-day mortality after hospital admission. We also controlled for the calendar year for each injury to account for period effects. We analyzed the time to death after hospital admission and time to return to work using Cox's proportional hazards frailty models. RESULTS: After multivariable adjustment, the odds ratio for prehospital mortality with PHTLS-trained prehospital staff was 1.54 (95% credibility interval, 1.07-2.13). For 30-day mortality among those surviving to hospital admission, the odds ratio was 0.85 (95% credibility interval, 0.45-1.48). There was no association between PHTLS training and time to death (hazard ratio = 0.99; 95% CI, 0.85-1.14) or time to return to work (hazard ratio = 0.98; 95% CI, 0.92-1.05). CONCLUSIONS: In this observational study, the implementation of PHTLS training did not appear to be associated with reduced mortality or ability to return to work after motor-vehicle traffic injuries.

Prehospital Trauma Life Support (PHTLS) training of ambulance caregivers and impact on survival of trauma victims.

BACKGROUND: The Prehospital Trauma Life Support (PHTLS) course has been widely implemented and approximately half a million prehospital caregivers in over 50 countries have taken this course. Still, the effect on injury outcome remains to be established. The objective of this study was to investigate the association between PHTLS training of ambulance crew members and the mortality in trauma patients. METHODS: A population-based observational study of 2830 injured patients, who either died or were hospitalized for more than 24 h, was performed during gradual implementation of PHTLS in Uppsala County in Sweden between 1998 and 2004. Prehospital patient records were linked to hospital-discharge records, cause-of-death records, and information on PHTLS training and the educational level of ambulance crews. The main outcome measure was death, on scene or in hospital. RESULTS: Adjusting for multiple potential confounders, PHTLS training appeared to be associated with a reduction in mortality, but the precision of this estimate was poor (odds ratio, 0.71; 95% confidence interval, 0.42-1.19). The mortality risk was 4.7% (36/763) without PHTLS training and 4.5% (94/2067) with PHTLS training. The predicted absolute risk reduction is estimated to correspond to 0.5 lives saved annually per 100,000 population with PHTLS fully implemented. CONCLUSIONS: PHTLS training of ambulance crew members may be associated with reduced mortality in trauma patients, but the precision in this estimate was low due to the overall low mortality. While there may be a relative risk reduction, the predicted absolute risk reduction in this population was low.

A pilot study of mechanical chest compressions with the LUCAS™ device in cardiopulmonary resuscitation.

AIM: The LUCAS™ device has been shown to improve organ perfusion during cardiac arrest in experimental studies. In this pilot study the aim was to compare short-term survival between cardiopulmonary resuscitation (CPR) performed with mechanical chest compressions using the LUCAS™ device and CPR performed with manual chest compressions. The intention was to use the results for power calculation in a larger randomised multicentre trial. METHODS: In a prospective pilot study, from February 1, 2005, to April 1, 2007, 149 patients with out-of hospital cardiac arrest in two Swedish cities were randomised to mechanical chest compressions or standard CPR with manual chest compressions. RESULTS: After exclusion, the LUCAS and the manual groups contained 75 and 73 patients, respectively. In the LUCAS and manual groups, spontaneous circulation with a palpable pulse returned in 30 and 23 patients (p = 0.30), spontaneous circulation with blood pressure above 80/50 mm Hg remained for at least 5 min in 23 and 19 patients (p = 0.59), the number of patients hospitalised alive >4h were 18 and 15 (p = 0.69), and the number discharged, alive 6 and 7 (p = 0.78), respectively. CONCLUSIONS: In this pilot study of out-of-hospital cardiac arrest patients we found no difference in early survival between CPR performed with mechanical chest compression with the LUCAS™ device and CPR with manual chest compressions. Data have been used for power calculation in a forthcoming multicentre trial.

Poor chest compression quality with mechanical compressions in simulated cardiopulmonary resuscitation: a randomized, cross-over manikin study.

INTRODUCTION: Mechanical chest compression devices are being implemented as an aid in cardiopulmonary resuscitation (CPR), despite lack of evidence of improved outcome. This manikin study evaluates the CPR-performance of ambulance crews, who had a mechanical chest compression device implemented in their routine clinical practice 8 months previously. The objectives were to evaluate time to first defibrillation, no-flow time, and estimate the quality of compressions. METHODS: The performance of 21 ambulance crews (ambulance nurse and emergency medical technician) with the authorization to perform advanced life support was studied in an experimental, randomized cross-over study in a manikin setup. Each crew performed two identical CPR scenarios, with and without the aid of the mechanical compression device LUCAS. A computerized manikin was used for data sampling. RESULTS: There were no substantial differences in time to first defibrillation or no-flow time until first defibrillation. However, the fraction of adequate compressions in relation to total compressions was remarkably low in LUCAS-CPR (58%) compared to manual CPR (88%) (95% confidence interval for the difference: 13-50%). Only 12 out of the 21 ambulance crews (57%) applied the mandatory stabilization strap on the LUCAS device. CONCLUSIONS: The use of a mechanical compression aid was not associated with substantial differences in time to first defibrillation or no-flow time in the early phase of CPR. However, constant but poor chest compressions due to failure in recognizing and correcting a malposition of the device may counteract a potential benefit of mechanical chest compressions.

No difference in autopsy detected injuries in cardiac arrest patients treated with manual chest compressions compared with mechanical compressions with the LUCAS device--a pilot study.

AIM: To compare the variety and incidence of internal injuries after manual and mechanical chest compressions during CPR. METHODS: In a prospective pilot study conducted in two Swedish cities, 85 patients underwent autopsy after unsuccessful resuscitation attempts with manual or mechanical chest compressions, the latter with the LUCAS device. Autopsy was performed and the results were evaluated according to a specified protocol. RESULTS: No injuries were found in 26/47 patients in the manual group and in 16/38 patients in the LUCAS group (p=0.28). Sternal fracture was present in 10/47 in the manual group and 11/38 in the LUCAS group (p=0.46), and there were multiple rib fractures (> or =3 fractures) in 13/47 in the manual group and in 17/38 in the LUCAS group (p=0.12). Bleeding in the ventral mediastinum was noted in 2/47 and 3/38 in the manual and LUCAS groups respectively (p=0.65), retrosternal bleeding in 1/47 and 3/38 (p=0.32), epicardial bleeding in 1/47 and 4/38 (p=0.17), and haemopericardium in 4/47 and 3/38 (p=1.0) respectively. One patient in the LUCAS group had a small rift in the liver and one patient in the manual group had a rift in the spleen. These injuries were not considered to have contributed to the patient's death. CONCLUSION: Mechanical chest compressions with the LUCAS device appear to be associated with the same variety and incidence of injuries as manual chest compressions.

Assessment of intravascular volume by transthoracic echocardiography during therapeutic hypothermia and rewarming in cardiac arrest survivors.

AIM: To study haemodynamic effects and changes in intravascular volume during hypothermia treatment, induced by ice-cold fluids and maintained by ice-packs followed by rewarming in patients after resuscitation from cardiac arrest. MATERIALS AND METHODS: In 24 patients following successful restoration of spontaneous circulation (ROSC), hypothermia was induced with infusion of 4 degrees C normal saline and maintained with ice-packs for 26 h after ROSC. This was followed by passive rewarming. Transthoracic echocardiography was performed at 12, 24 and 48 h after ROSC to evaluate ejection fraction and intravascular volume status. Central venous pressure (CVP), central venous oxygen saturation (ScvO(2)) and serum lactate were measured. Fluid balance was calculated. RESULTS: Twelve hours after ROSC, two separate raters independently estimated that 10 and 13 out of 23 patients had a decreased intravascular volume using transthoracic echocardiography. After 24 and 48 h this number had increased further to 14 and 13 out of 19 patients and 13 and 12 out of 21 patients. Calculated fluid balance was positive (4000 ml the day 1 and 2500 ml day 2). There was no difference in ejection fraction between the recording time points. Serum lactate and ScvO(2) were in the normal range when echocardiography exams were performed. CVP did not alter over time. CONCLUSIONS: Our results support the hypothesis that inducing hypothermia following cardiac arrest, using cold intravenous fluid infusion does not cause serious haemodynamic side effects. Serial transthoracic echocardiographic estimation of intravascular volume suggests that many patients are hypovolaemic during therapeutic hypothermia and rewarming in spite of a positive fluid balance.