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Petter A Steen

Publications and source records attributed to Petter A Steen.

13 recordsLinked to original sources
PubMed2006

Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest.

BACKGROUND: Cardiopulmonary resuscitation (CPR) and electrical defibrillation are the primary treatment options for ventricular fibrillation (VF). While recent studies have shown that providing CPR prior to defibrillation may improve outcomes, the effects of CPR quality remain unclear. Specifically, the clinical effects of compression depth and pauses in chest compression prior to defibrillation (pre-shock pauses) are unknown. METHODS: A prospective, multi-center, observational study of adult in-hospital and out-of-hospital cardiac resuscitations was conducted between March 2002 and December 2005. An investigational monitor/defibrillator equipped to measure compression characteristics during CPR was used. RESULTS: Data were analyzed from 60 consecutive resuscitations in which a first shock was administered for VF. The primary outcome was first shock success defined as removal of VF for at least 5s following defibrillation. A logistic regression analysis demonstrated that successful defibrillation was associated with shorter pre-shock pauses (adjusted odds ratio 1.86 for every 5s decrease; 95% confidence interval 1.10-3.15) and higher mean compression depth during the 30s of CPR preceding the pre-shock pause (adjusted odds ratio 1.99 for every 5mm increase; 95% confidence interval 1.08-3.66). CONCLUSIONS: The quality of CPR prior to defibrillation directly affects clinical outcomes. Specifically, longer pre-shock pauses and shallow chest compressions are associated with defibrillation failure. Strategies to correct these deficiencies should be developed and consideration should be made to replacing current-generation automated external defibrillators that require long pre-shock pauses for rhythm analysis.

Aged↗
PubMed2006

Scoring of anatomic injury after trauma: AIS 98 versus AIS 90--do the changes affect overall severity assessment?

BACKGROUND: Although several changes were implemented in the 1998 update of the abbreviated injury scale (AIS 98) versus the previous AIS 90, both are still used worldwide for coding of anatomic injury in trauma. This could possibly invalidate comparisons between systems using different AIS versions. Our aim was to evaluate whether the use of different coding dictionaries affected estimation of Injury Severity Score (ISS), New Injury Severity Score (NISS) and probability of survival (Ps) according to TRISS in a hospital-based trauma registry. MATERIALS AND METHODS: In a prospective study including 1654 patients from Ulleval University Hospital, a Norwegian trauma referral centre, patients were coded according to both AIS 98 and AIS 90. Agreement between the classifications of ISS, NISS and Ps according to TRISS methodology was estimated using intraclass correlation coefficients (ICC) with 95% CI. RESULTS: ISS changed for 378 of 1654 patients analysed (22.9%). One hundred and forty seven (8.9%) were coded differently due to different injury descriptions and 369 patients (22.3%) had a change in ISS value in one or more regions due to the different scoring algorithm for skin injuries introduced in AIS 98. This gave a minimal change in mean ISS (14.74 versus 14.54). An ICC value of 0.997 (95% CI 0.9968-0.9974) for ISS indicates excellent agreement between the scoring systems. There were no significant changes in NISS and Ps. CONCLUSIONS: There was excellent agreement for the overall population between ISS, NISS and Ps values obtained using AIS 90 and AIS 98 for injury coding. Injury descriptions for hypothermia were re-introduced in the recently published AIS 2005. We support this change as coding differences due to hypothermia were encountered in 4.3% of patients in the present study.

Abbreviated Injury Scale↗
PubMed2006

Assessing quality of care in a trauma referral center: benchmarking performance by TRISS-based statistics or by analysis of stratified ISS data?

BACKGROUND: Using prospectively collected data from Ulleval University Hospital in Norway, standard TRISS-based methods with case mix correction were compared with analysis based on ISS stratified data. METHODS: Reference data were The Major Trauma Outcome Study (MTOS) controlled sites, used for calculation of AIS 90 based TRISS coefficients. Present TRISS convention requires RTS scoring on hospital admission, excluding many severely injured patients intubated before arrival. Therefore, all Ulleval patients were RTS scored using prehospital data if needed. RESULTS: There was 6.6% of MTOS controlled sites patients (mortality rate 26.7%) that had been excluded before estimation of TRISS coefficients because of lack of data for Ps calculation. Analyses based on ISS stratified data included these patients and indicated significant better performance at Ulleval for blunt, but not for penetrating trauma. No TRISS-based analysis detected this difference. CONCLUSIONS: The RTS convention should be changed to reduce patient exclusion. Presently, stratified ISS based data should also be analyzed.

Adult↗
PubMed2005

Performing procedures on the newly deceased for teaching purposes: what if we were to ask?

BACKGROUND: Performance of procedures on the recently dead for physician training is controversial. It has been suggested that permission be obtained. We investigated whether patients and family members would grant such permission or if even this request might anger the recently bereaved. METHODS: Physicians administered identical surveys to adult emergency department patients and family members in Brooklyn and Oslo to determine their willingness to consent for teaching of specific invasive techniques in the event of their own death or that of a family member. Demographic factors and location (culture) were assessed for effects. RESULTS: Willingness to consent was directly related to age of decedent and inversely related to perceived invasiveness of the procedure at both sites. In every scenario, respondents in Brooklyn were much less willing to grant permission (2- to 2.5-fold) than were those in Oslo. In Oslo, respondents were more willing to consent for their own bodies to be used as training tools than that of a relative. In Brooklyn, 48.5% would be angry if approached for permission compared with only 8.4% in Oslo (P<.001). CONCLUSIONS: Asking for permission to perform procedures on the recently deceased for physician training purposes may often anger the bereaved. The emotional response to the consent request may be culturally determined. Increased willingness of individuals to permit the use of their bodies in the immediate postmortem period suggests that a preauthorization program similar to organ donor cards might be acceptable, successful, and ethical.

Adult↗
PubMed2005

A probabilistic neural network as the predictive classifier of out-of-hospital defibrillation outcomes.

INTRODUCTION: Although modern defibrillators are nearly always successful in terminating ventricular fibrillation (VF), multiple defibrillation attempts are usually required to achieve return of spontaneous circulation (ROSC). This is potentially deleterious as cardiopulmonary resuscitation (CPR) must be discontinued during each defibrillation attempt which causes deterioration in the heart muscle and reduces the chance of ROSC from later defibrillation attempts. In this work defibrillation outcomes are predicted prior to electrical shocks using a neural network model to analyse VF time series in an attempt to avoid defibrillation attempts that do not result in ROSC. METHODS: The 198 pre-shock VF ECG episodes from 83 cardiac arrest patients with defibrillation conversions to different outcomes were selected from the Oslo ambulance service database. A probabilistic neural network model was designed for training and testing with a cross validation method being used for the better generalisation performance. RESULTS: We achieved an accuracy of 75% in overall prediction with a sensitivity of 84% and a specificity of 65% using VF ECG time series of an order of 1 s in length. CONCLUSION: Pre-shock VF ECG time series can be classified according to the defibrillation conversion to a return of spontaneous circulation (ROSC) or No-ROSC.

Area Under Curve↗
PubMed2005

Twelve-month retention of CPR skills with automatic correcting verbal feedback.

AIM: To evaluate the retention of CPR skills 12 months after initial training, using a manikin equipped with a computer-based voice advisory feedback system. METHODS: Thirty-five volunteers had individual 20 min training sessions without an instructor on a manikin with computer-based voice advisory feedback. The feedback depended on the performance as measured by the manikin computer system versus set limits for ventilation and compression variables. Twelve of the volunteers received additional ten 3-min self-training sessions during the following month making a total of 50 min training. All ventilation and compression variables when the volunteers were tested before, immediately after and 6 months after training have previously been reported. The volunteers were now tested 12 months after the initial training session with activated feedback. RESULTS: There were virtually no changes in CPR skills when tested with active feedback 12 months after initial training versus immediately or 6 months post-training. The only exception was a slightly lower number of compressions per minute at 12 months versus immediate post-training in the subgroup with 20 min of initial training, 47+/-4 versus 52+/-4, p = 0.008. There were no differences between the 20 and 50 min training subgroups at 12 months. CONCLUSIONS: Computer-based voice advisory feedback can improve the performance of basic life support skills on a manikin with no deterioration in feedback supported performance after 12 months.

Cardiopulmonary Resuscitation↗
PubMed2004

Improved prediction of defibrillation success for out-of-hospital VF cardiac arrest using wavelet transform methods.

We report an improved method for the estimation of shock outcome prediction based on novel wavelet transform-based time-frequency methods. Wavelet-based peak frequency, energy, mean frequency, spectral flatness and a new entropy measure were studied to predict shock outcome. Of these, the entropy measure provided optimal results with 60 +/- 6% specificity at 91 +/- 2% sensitivity achieved for the prediction of return of spontaneous circulation (ROSC). These results represent a major improvement in shock prediction in human ventricular fibrillation.

Electric Countershock↗
PubMed2002

Retention of basic life support skills 6 months after training with an automated voice advisory manikin system without instructor involvement.

AIM: To evaluate the retention of skills 6 months after training in ventilation and chest compressions (CPR) on a manikin with computer based on-line voice advisory feedback and the possible effects of initial overtraining. METHODS: Thirty five volunteers had 20 min provisional CPR training on a manikin with computer based voice advisory feedback but without an instructor. The appropriate feedback was taken from a pre-recorded list depending on performance measured by the manikin--computer system versus set limits for ventilation and compression variables. One group in addition was randomised to receive 10 similar 3 min training sessions during 1 week in the following month (overtrained group). All ventilation and compression variables were measured without feedback before and after the initial training session, with feedback immediately thereafter, and both without and with feedback 6 months after the initial training session. RESULTS: The initial training improved all variables. Compressions with correct depth increased from a mean of 33 to 77%, and correct inflations from a mean of 9 to 58%. After 6 months, the results for the controls were not significantly different from pre-training, except for a higher of correct inflations (18%), while the overtrained group had better retention of skills including the correct compression depth (mean 61%) and inflations (mean 42%). When verbal feedback was added both the compressions and ventilations immediately improved both when tested immediately and 6 months after the initial training session. CONCLUSIONS: The computer-based voice advisory manikin (VAM) feedback system can improve immediate performance of basic life support (BLS) skills, with better long-term retention with overtraining.

Adult↗
PubMed2002

Advanced life support drugs: do they really work?

Basic life support and rapid defibrillation for ventricular fibrillation or pulseless ventricular tachycardia are the only two interventions that have been shown unequivocally to improve survival after cardiac arrest. Several drugs are advocated to treat cardiac arrest, but despite very encouraging animal data, no drug has been reliably proven to increase survival to hospital discharge after cardiac arrest. This review focuses on recent experimental and clinical data concerning the use of vasopressin, amiodarone, magnesium, and fibrinolytics during advanced life support (ALS). Animal data indicate that, in comparison with epinephrine (adrenaline), vasopressin produces better vital organ blood flow during cardiopulmonary resuscitation (CPR). These apparent advantages have yet to be converted into improved survival in large-scale trials of cardiac arrest in humans. Data from two prospective, randomized trials suggest that amiodarone may improve short-term survival after out-of-hospital ventricular fibrillation cardiac arrest. On the basis of anecdotal data, magnesium is recommended therapy for torsades de pointes and for shock-resistant ventricular fibrillation associated with hypomagnesemia. In the past, CPR has been a contraindication to giving fibrinolytics, but several studies have demonstrated the relative safety of fibrinolysis during and after CPR. Fibrinolytics are likely to be beneficial when cardiac arrest is associated with plaque rupture and fresh coronary thrombus or massive pulmonary embolism. Fibrinolysis may also improve cerebral microcirculatory perfusion once a spontaneous circulation has been restored. A planned, prospective, randomized trial may help to define the role of fibrinolysis during out-of-hospital CPR.

Advanced Cardiac Life Support↗