VASCULAR ASPECTS OF PRESSURE ULCERS. Harvey N. Mayrovitz, Ph.D. College of Medical Sciences Nova Southeastern University

Transcription

1 VASCULAR ASPECTS OF PRESSURE ULCERS Harvey N. Mayrovitz, Ph.D. College of Medical Sciences Nova Southeastern University

2 Problem Ponder Potentiate Pursue Pin-it-Down Party

3 Pressure Ulcer Epidermis Dermis Fat Compressed Vasculature Bone Muscle

4 Sustained Blood Flow Reduction How Much? How Long? Where? Pressure Intermittent Adaptation During Load? Off-Load Interval Recovery? Recovery Potential? Tissue Injury and Breakdown Moisture-Temperature-Nutrition -Vascular Status-Age

5 COMMON PRESSURE ULCER SITES Scapula Sacrum Ischium Iliac Crest Trochanter Malleolus Heel Foot Edge After Maklebust & Sieggreen, 1996

6 Skin Dermis Epidermis Hair Pore Duct Capillary Arteriole Nerve Artery Fat

7 O 2 O 2 Epidermis H 2 O CO 2 O 2 Vein Lymphatic Skin Circulation Artery

8 Tissue Loading Force P o (+) Epidermis (-) Capillary Blood Flow (+) Pressure Resistance 1997 HN Mayrovitz Compression (-) Reduced Blood Flow Distortion Twisting Kinking V A

9 Tissue Effects Force O 2 (-) Epidermis CO 2 (+) O 2 (-) V H 2 O (+) (-) Intravascular Changes 1997 HN Mayrovitz Reduced Blood Flow A

10 Defensive Measures Epidermis Compensatory Vascular Responses

11 Detection of Blood Flow Changes Low Resting Flow Occluded Flow Restored Flow LASER-DOPPLER 0 500

12 BLOOD PERFUSION BY LASER-DOPPLER IMAGING Baseline Heat-off min Forearm Heated to 44 o o C

13 Trochanter Perfusion Subject B - Static Support LD Perfusion (a.u.) Laser-Doppler Flowmetry Study Female, >60 Supine Hip-Down Supine Time (min) Subject: 68, 5' 8", lbs., lb, 64 yrs, year hypertensive old, female female.

14 Trochanter Perfusion Subject B - Dynamic Surface 5 LD Perfusion (a.u.) Supine Hip-Down Supine Time (min) Subject: 68, 5' 200 8", 200lbs., lb, 64 yrs, 64 year hypertensive old, hypertensive femalefemale.

15 LD Perfusion (a.u.) Support Surface Impact on Trochanter Blood Perfusion ** A * ** p=0.02, p= Dynamic surface Static surface * Pre-Load Baseline 0-15 min Loading Error bars are sem Error bars are +/- 1 sem min Loading

16 Clear Surface Laser-Doppler Probe Laser-Doppler Imager

17 Heel LDI Images Before, During and After Loading Hyperemia 40 Supine Lying

18 Overall Blood Perfusion Sequential Changes 4 LDI PERFUSION (a.u.) N=11 Subjects N=11 subj ects x 10 mm Area 10 mm x 10 mm area (mean +/- 2 sem) mean +/- 2 sem * * * * * * TIME (minutes)

19 Load Placement on Heel Laser-Doppler Imager Heater Placement on Heel

20 Protocol Sequence History, Demographics & Vascular Assessments Subject Placed Prone - 10-min rest interval Unloaded Heel Perfusion (Laser-Doppler Imaging, LDI) 10-min Load Duration Heel loaded - 30 mmhg Load removed Sequential LDI Scans until perfusion recovery Repeat: 60, 120,140 mmhg Heel heated (44 o C-5-min) & post-heat LDI scans One Week Apart 120 mmhg Load Heel loaded minutes Load removed Sequential LDI Scans until perfusion recovery Repeat: 5, 10, 20 minutes Heel heated (44 o C-5-min) & post-heat LDI scans

21 Post-Loading Laser Doppler Images Baseline Sequential LDI scans after load removal 1/min 120 mmhg for 10-min

22 Peak Perfusion (% of Heated Max) 100 (A) Fixed Load 90 (120 mmhg) Load Duration (minutes) HYPEREMIA Post-load Hyperemia appears to peak after 5-10 minutes of 120 mmhg Peak Perfusion (% of Heated Max) (B) Fixed Duration 80 (10 minutes) Load Magnitude (mmhg) Post-load Hyperemia precipitously increases between mmhg when loaded for 10-min

23 Recovery Time (Tr, min) Recovery Time (Tr, min) (A) Fixed Load (120 mmhg) Tr = 2.58D0.36 r 2 = 0.419, p<0.001 N=14, n= Load Duration (D, min) (B) Fixed Duration (10 minutes) Load Duration = 10 minutes Subjects = 14 Females 3 Tr = 0.12P r 2 = 0.600, p< N=14, n= Load Magnitude (P, mmhg) RECOVERY Recovery Time increases up-to a load duration of about 10 minutes Recovery Time increases up-to a load magnitude of about 120 mmhg

24 Hyperemia Depends on Combined Pressure & Duration 6 Heel Perfusion (Peak / Baseline) Each point is mean of all subjects y = x - 2E-06x 2 R 2 = Pressure-Duration (mmhg-minutes)

25 Recovery Depends on Combined Pressure & Duration 9 Recovery Time (min) Each point is mean of all subjects y = x - 1E-06x 2 R 2 = Pressure-Duration (mmhg-minutes)

26 PRE-LYING BLOOD PERFUSION STATIC SURFACE DYNAMIC 15 cycle/hr

27 TWO-HOUR SUPINE LYING STATIC SURFACE DYNAMIC 15 cycle/hr

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29 Chug Along Solve the Jump Start RESEARCH

30 Pressure Tissue - Vascular Compression & Distortion Blood Flow Reduction or Cessation Tissue & Vascular Deficits, Injury and Breakdown

31 Perfusion Responses by Key Intervals 4 LDI PERFUSION (a.u.) N=11 subjects 10 x 10 mm Area (mean +/- sem) * * * * * * PRE-LOAD AVERAGE DURING LOAD (minutes) OFF-LOADED (minutes)

32 Subjects N = 20 women Avg. sem Range Height (inches) Weight (lbs.) BSA (kg/m 2 ) Age (years) Laser-Doppler Flowmetry Study