Posterior Stroke Recognition in the Prehospital Setting

Adam Oostema, MD, FACEP

Associate Professor

Emergency Medicine

Michigan State University

College of Human Medicine

Disclosures

• Michigan’s Ongoing Stroke Registry to Accelerate Improvement in Care (MOSAIC), Michigan Department of Health and Human Services.

• American Heart Association Mentored Clinical and Population Science Award

Objectives

Review the benefits of optimal prehospital stroke recognition

1

Discuss challenges in posterior stroke recognition

2

Share findings form a pilot controlled before and after study of an educational intervention to improve prehospital stroke recognition

3

The Value of EMS in Stroke

Systems

• Arrival by EMS versus other mode1

o Arrive earlier

o Receive CT faster

o Receive t-PA more often

• Prenotification among EMS-transported strokes2,3

o Receive CT faster

o Receive t-PA more often

o Receive t-PA faster

1. Ekundayo et al. Circulation: Cardiovascular Quality and Outcomes 2013;6(3): 262-2692. Lin et al. Circulation: Cardiovascular Quality and Outcomes 2012;5(4): 514-5223. Oostema et al. J Stroke Cerebrovasc Dis 2014;23(10): 2773-2779

Goals of Prehospital Stroke Care

RECOGNIZE STROKE MINIMIZE TRANSPORTATION DELAY

PRENOTIFY RECEIVING HOSPITAL

EMS Stroke Recognition and Quality Measure Compliance

0

10

20

30

40

50

60

70

80

90

100

Dispatchedhighest priority

Response time ≤ 8 minutes

CPSS On-scene time ≤ 15 minutes

Glucose levelrecorded

LKW documented Hospital pre-notification

Transportedhighest priority

EMS Recognized EMS Unrecognized

Oostema JA, et al. J Stroke CerebrovascDis 2014;23(10): 2773-2779

EMS Stroke Recognition and ED Stroke Care

DTCT time t-PA

EMS Recognized 34.6 14.9

EMS Unrecognized 84.7 4.4

0

10

20

30

40

50

60

70

80

90

Min

(D

TCT)

or

Pe

rce

nt

(t-P

A)

EMS Recognized EMS Unrecognized

Oostema et al. J Stroke Cerebrovasc Dis 2014;23(10): 2773-2779

EMS Stroke Recognition

Sensitivity:

Overcalls:

Cincinnati Prehospital Stroke Scale and EMS Stroke Recognition

CPSS documented

CPSS NOTdocumented

Likelihood of identifying stroke (Sensitivity)

84.7% 30.9%

Likelihood of accurately calling stroke (Positive Predictive Value)

56.2% 30.4%

Oostema JA et al. Stroke 2015;46: 1513-7

Unrecognized Strokes

Generalized Weakness

23%

Altered Mental Status14%

Dizziness10%

Focal Neurologic Finding10%

Cardiovascular 7%

Diabetic 6%

Other/Not Specified

30%

Oostema JA, et al. Stroke 2015;46(6):1531-7

5

Clinical Presentation EMS RecognizedN=141

EMS UnrecognizedN=45

P-value

NIHSS 10 (4-19) 4 (1-9) <0.001

Unilateral Weakness 104 (73.8) 22 (48.9) 0.010

Aphasia 55 (39.0) 16 (35.6) 0.678

Dysarthria 69 (48.9) 19 (42.2) 0.432

Visual Disturbance 31 (22.0) 11 (25.6) 0.731

Altered Mental Status 28 (19.9) 8 (18.6) 0.758

Ataxia 18 (12.8) 13 (30.2) 0.011

Headache 18 (12.8) 13 (30.2) 0.230

Vertigo 8 (5.7) 7 (16.3) 0.034

Non-Vertigo Dizziness 8 (5.7) 4 (9.3) 0.445

Vomiting 6 (4.3) 5 (11.6) 0.090

Oostema JA et al. Stroke 2015;46: 1513-7

Posterior Circulation Ischemic

Stroke

http://commons.wikimedia.org/wiki/File:Cerebral_vascular_territories.jpg

• Motor deficits

• Sensory deficits

• “Crossed” syndromes

• Homonymous hemianopia

• Ataxia, imbalance, unsteadiness, or disequilibrium

• Vertigo

• Diplopia

• Dysphagia or dysarthria

• Isolated reduced level of consciousness

Merwick BMJ 2014;384:g3175

Clinical Presentation

Sarraj et al. Int J Stroke. 2015;10:672-678

The Grand Rapids Area Prehospital Stroke Registry (GRAPHS)

• Registry of EMS Transported Patients who were EITHER:o EMS primary or secondary impression of stroke/TIA, ORo Hospital discharge diagnosis of stroke/TIA

• Kent County Michigano Population 600,000

o EMS System

• 3 Independent EMS agencies (annual transport volume 55,000)

• All ALS medical transport

o Hospitals

• 4 Acute Care Hospitals/3 Health Systems (Over 1500 licensed beds)

• All Certified Primary Stroke Centers

• Funding: American Heart Association Mentored Clinical and Population Science Award (2015-2017)

http://www.mapsopensource.com/images/location-map-of-kent-county-michigan.gif

Intervention

• Educationo On-line module

o Mandatory for all paramedics

o Presented local performance data

o Highlighted benefits of quality measure compliance

o Underscored screening for stroke in ambiguous presentations

• Assessmento Pre and Post Test

http://commons.wikimedia.org/wiki/File:Cerebral_vascular_territories.jpg

Anterior

Circulation:

- Weakness

- Numbness

- Difficulty Speaking

- Neglect

Posterior

Circulation:

- Vertigo

- Balance difficulty

- Double Vision

- Loss of Vision

Clinical Symptoms

Finger-to-Nose Test

• Test for limb ataxia

• Element of the NIH stroke scaleo Limb ataxia present in 30% of EMS unrecognized stroke cases

in our pilot registry

• Reasonable inter-rater reliabilityo Kappa 0.511 to 0.682

• Easy to teach

• Integrates well into existing prehospital stroke scale (CPSS)

1. Brott et al. Stroke 20(7): 864-870.2. Hansen et al. Acta Neurol Scand 90(3): 145-149.

https://www.k4health.org/toolkits/measuring-success/types-evaluation-designs

Largest Agency

General Stroke Training + FTN

General Stroke Training

12 Months 9 Months

12 Months 9 Months

2 Smaller Agencies

Characteristics of 139 EMS Transported Posterior Ischemic Strokes

Control

(n=88)

FTN

(n=51)

Before

(n=74)

After

(n=65)

Median Age (IQR) 76 (64 to 85) 74 (65 to 86) 79 (67 to 87) 73 (63 to 84)

Female 35 (39.8) 23 (45.1) 31 (41.8) 27 (41.5)

Non-White Race 11 (21.6) 14 (15.9) 15 (20.3) 10 (15.4)

Dispatched for Stroke 30 (34.1) 22 (43.1) 24 (32.4) 28 (43.1)

Vomiting 18 (20.5) 8 (15.7) 13 (17.6) 13 (20.0)

Headache 16 (18.2) 5 (9.8) 12 (16.2) 9 (13.9)

Dizziness 22 (25.0)* 5 (9.8)* 12 (16.2) 15 (23.1)

Ataxia 14 (15.9) 5 (9.8) 6 (8.1) 13 (20.0)

Gaze Preference/Nystagmus 4 (4.6) 4 (7.8) 6 (8.1) 2 (3.1)

Vision Change 5 (5.7) 3 (5.9) 5 (6.8) 3 (4.6)

NIHSS (IQR) 5 (2 to 11) 6 (2 to 9) 7 (3 to 13) 3 (1 to 7)

DTCT ≤25 Min 23 (26.4) 12 (23.5) 19 (25.7) 16 (24.6)

t-PA 13 (14.8) 4 (7.8) 8 (10.8) 9 (13.9)

Primary and secondary outcomes by study group and period

Control (N=88) FTN (N=51)

Before

(n=50)

After

(n=38)p-value

Before

(n=24)

After

(n=27)p-value

EMS Recognition (%) 16 (32.0) 15 (39.5) 0.467 11 (45.8) 20 (74.1) 0.039

Mean DTCT Time (SD) 58 (46) 61 (47) 0.771 62 (43) 41 (22) 0.037

t-PA Delivery (%) 5 (10.0) 8 (21.5) 0.148 3 (12.5) 1 (3.7) 0.244

EMS posterior stroke

recognition by study quarter

Intervention

Limitations

Small pilot study Insufficient sample size for multivariable analysis

Single county All ALS EMS system

Reason for Improvement Unclear Effect of education or change in evaluation process?

Conclusions

A larger study in diverse practice settings is needed to confirm these results and explore

sustainability of these gains

Improved recognition may translate into faster ED stroke evaluations

Educating paramedics in the finger-to-nose exam may improve prehospital posterior

stroke recognition rates

Value of EMS Recognition

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

DTCT <25 Min t-PA Delivery DTNT <45 Min

EMS Recognized EMS Unrecognized

Focus Groups

• Interview with paramedics from each agency in Kent County

• Focus group recordings were transcribed and uploaded into Dedoose (Version 6.1.18, Los Angeles, CA) for analysis

• Themes and subthemes that described barriers and facilitators of prehospital stroke care were developed iteratively by 3 investigators using grounded theory methods

• Interview with paramedics from each agency in Kent County

• Focus group recordings were transcribed and uploaded into Dedoose (Version 6.1.18, Los Angeles, CA) for analysis

• Themes and subthemes that described barriers and facilitators of prehospital stroke care were developed iteratively by 3 investigators using grounded theory methods

Focus Groups

Proposed Measures

• Stroke-1: Prehospital stroke assessment documented for suspected stroke

• Stroke-2: Blood glucose measurement for suspected stroke

• Stroke-3: Prehospital notification

• Stroke-4: Suspected stroke transported to an ‘acute stroke ready’ hospital

• Stroke-5: Documentation of last known well

• Stroke-7: Time from LKW to arrival at stroke hospital

• Stroke-8: Percentage of ED-diagnosed stroke recognized by EMS

http://www.emscompass.org/ems-compass-measures/

Why Focus on These Measures?

Recognition

Stroke-1: Prehospital stroke assessment documented for suspected stroke

Stroke-2: Blood glucose measurement for suspected stroke

Stroke-8: Percentage of ED-diagnosed stroke recognized by EMS

Efficiency

Stroke-3: Prehospital notification

Stroke-4: Suspected stroke transported to an ‘acute stroke ready’ hospital

Stroke-5: Documentation of last known well

Stroke-7: Time from LKW to arrival at stroke hospital

EMS Stroke Care Model

• Stroke Screening

• Glucose Check

In-Hospital Stroke

Response

EMS Stroke Recognition

Patient Outcomes

Hospital Pre-

notification

Venkat, A et al. Neuroepidemiology 2018;51: 123-27