The Prospective Study In Reliability And Validity Of The LosAngeles Prehospital Stroke Screen (LAPSS) Using By Prehospital Personnel

Objectives:The complete stroke treatment consists ofseven courses, such as health education, primary prevention,prehospital treament, acute stage treatment, rehabilization,returning to society and secondary prevention. Prehospitaltreament is composed of early identification and early using ofneuroprective drugs. Whereas the poor acurancy in prehospitaldiagnosis of stroke need improving urgently and earlyidentification can be achieved by means of prehospital strokescreen. In order to improve the acurancy in prehospitaldiagnosis of stroke and set up a prehospital stroke scale suitablefor China, in this study, we prospectively evaluate the reliabilityand validity of the LosAngeles Prehospital StrokeScreen(LAPSS) using by prehospital personnel for Chinesestroke victims .At the same time we add 2 items to LAPSS inorder that the scale can be more effective in identifying strokevictims of vertebro-basilar artery system and prospectivelyevaluate the reliability and validity ofthe adaption version ofLAPSS(LAPSS-2).Methods:We have searched for a prehospital stroke scalein CMCC and CBM and found nothing . We have retrieved inMedline in MeSH and found 7 kinds of way in troke earlyidentification,such as Cincinnati Prehospital StrokeScale(CPSS),FAST(FACE\ARM\SPEECH TEST), LosAngelesPrehospital Stroke Screen(LAPSS), Experience with aQuestionaire administered by emergency medical service forPre-hospital identification of patients with stroke, Shorteningthe NIHSS for use in the Prehospital setting, Improvedparamedic sensitivity stroke victims in the prehospital setting ,Telestroke as the application of telemedicine for stroke. LAPSSis more suitable than others for its higner reliability and validity.We have translated LAPSS into Chinese referring to the Chinesevesion of LAPSS by Professor ShenHong in the GeneralHospital of PLA and the Chinese vesion of LAPSS by BNC. Weadd 2 items to LAPSS and get a revised edition(LAPSS-2) inorder that the scale can be more effective in identifying strokevictims of vertebro-basilar artery system. According to theinclusion criterion, study participants are consecutive patientsadmitted by"120 "in the emergency center of Tang ShanWorker's hospital ,who should meet the following needs: (1)>18years, (2)neurologically relevant complaint such as alerteredlevel of consiciousness , local neurological signs, headache,seizure, syncope, the cluster category of weak\dizzy\sick,(3)absence of coma, and (4)nontraumatic presentation.Screen test need suitable and enogh sample size. Sample sizecan be caculated just as sampling survey in rate.Sensitivity,specificity,significance level, permit error shoud beprimarily established.When Sensitivity ands pecificity are nearly50%, formula n=(ua/d)²[?(1-?)] can be used. .When Sensitivityands pecificity are >80% or <20%, formula n={57.3ua/sin^–1d/[?(1-?)] }² shoud be used. Sample size of case group can becaculated when p means sensitivity . Sample size of controlgroup can be caculated when p means specificity. Case groupand control group are divided by Gold Standard.In this study, wemust use formula n={57.3ua/sin^–1d/[?(1-?)] }² f or partialdistribution. A prehospital diagnosis in the field of stroke ornon-stroke in 208 patients using Lapss, Lapss-2 was given bydoctors in emergency center Tang Shan Worker's hospital. GoldStandard is determined in the way of "clinic +imagination ".Diagnosis depenting on the imagination and record ofemergency department /inpatient department is made by oneneuroligist with masking .If the diagnosis agrees with the finaldiacharge diagnosis, a diagnosis of stroke will be made then. Ifthe diagnosis does not agrees with the final diacharge diagnosis,a director will make the final diagnosis with blinding as goldstandard according to the imagination and record of emergencydepartment /inpatient department / diacharge diagnosis. Weevaluate the reliability in 60 consecutive randomized patients( including retest and inter-test reliability ) by using Kappacorrelation .We evaluate the validity by using Sensitivity,Specifity, Positive predict value, Negative predict value,Accurancy and likelihood.Results:LAPSS and LAPSS-2 all demonstrated excellentreliability in test-retest and inter-test. (Kappa correlation rangedfrom 0.6 to 0.9) .The test-retest reliability in the Chinesevesion of LAPSS is K=0.79 and inter-test reliability is K=0.72 .The test-retest reliability in the revised edition of LAPSS isK=0.77 and inter-test reliability is K=0.64 .LAPSS andLAPSS-2 both demonstrated excellent validity in terms ofSensitivity(Sen), Specificity(Spe), Positive predict value(Ppv),Negative predict value(Npv) , Positive likelihoodratio(+LR),Negative likelihood ratio(-LR). For LAPSS,Sen(90.8%) 95%CI(86%-95.6%) Spe(97.1%) 95%CI(94.4%-99.8%)Ppv (96.7%) 95%CI(93.7%-99.7%)Npv(91.9%) 95%CI(87.7%-96.1%)+LR=31.3 –LR=0.095; For LAPSS-2,Sen(96.9%) 95%CI(94.0%-99.8%)Spe (96.2%) 95%CI(93.1%-99.3%) Ppv (96.0%) 95%CI(92.8%-99.2%)Npv(97.1%) 95%CI(94.4%-99.8%)+LR=25.5 -LR=0.032. In 9stroke patients who were not identified correctly by LAPSS , 6patients were identified by LAPSS-2 , 4 of them were cerebralinfarction in brain stem (2 Top of basilar arterary syndrome , 1Lock in syndrome , 1 Wallenberg syndrome) , 2 of them wereintracerebral hemorrhage .We were surprised to find that thesensitivity in LAPSS-2 had improved with the false-negativedecreased and that the specificity in LAPSS-2 had not beenaffected obviously .Conclusion: Both the LosAngeles Prehospital StrokeScreen(LAPSS) and the adaption version of LAPSS(LAPSS-2)...