Alfred A. Bove, MD, PhD Temple University Medical School Philadelphia, Pa
DISCLOSURE Relevant Financial Relationship(s) Consultant – Insight Telehealth Systems LLC Grant/Research Support – Astellas Pharma
Off Label Usage None
Page 1
Learning Objectives Familiarize the attendees on problems of inert gas kinetics in varying pressure exposures Understand the role of Patent Foramen Ovale in various decompression environments Improve knowledge of clinical decompression sickness syndromes
The defect allows an intermittent R to L shunt Paradoxical embolism is possible Thrombus can migrate from RA to LA Risk for CVA may be increased Migraine headache may be related Risk for DCS may be increased Arterial desaturation is possible
Page 2
Page 3
Pressure feet 16000 12000 8000 4000 -Sea level - 0 33 Depth 66 in 99 seawater 132 165
ATM 0.54 0.64 0.74 0.86 1 2 3 4 5 6
Altitude above sea level
mm Hg 412 483 564 656 760 1520 2280 3040 3800 4560
psi 8.0 9.3 10.9 12.7 14.7 29.4 44.1 58.8 73.5 88.2
Boyles Law 100
2.0% 2.4%
80
2.8% 3.4%
60
5.2%
5000 LUNG VOLUME - ml
4.1%
4000
40
3000
6.7% 9.0%
2000
20
1000
12.7% 19.2%
0 0
50
100 DEPTH -fsw
150
200
SURFACE
Page 4
32.7%
Henry’s Law 66 feet
Pressure - atm
3
N2 content proportional to Partial Pressure
2
PPN2 = 0.79•Pamb 1
Surface 0
3
6
9
12
DIVE TIME - hr
JBS Haldane
Boycott AE, Damant GCC, Haldane J: The prevention of compressed air illness. J Hyg (Cambridge) 8:342–443, 1908.
Page 5
Bubble Presence BUBBLE DETECTION STUDIES DIVE STUDY
DSAT 6x6 DSAT 4x6
DAN*
TOTAL DIVES
51
475
508
DIVES WITH BUBBLES
17
45
94
% WITH BUBBLES
33
10
19 * live aboard dive boat
Bubble presence
Multiday Repetitive Diving
Transcutaneous Doppler 73% of 260 dives caused bubbles 93% of divers bubbled in one or more dives
Dunford et al, 1992
Page 6
Diving Disorders Direct Pressure Effects Barotrauma Ascent
Indirect Pressure Effects Decompression Sickness
Narcosis/HPNS
Other Marine Injury/toxins
Descent
Henry Pulmonary Barotrauma
Ear Barotrauma Perilymph Fistula
Arterial gas Embolism Sinus Barotrauma Pneumothorax
Boyle
Tooth Barotrauma Pneumomediastinum mask/suit barotrauma GI Barotrauma Alternobaric Vertigo
A variable intracardiac shunt at the atrial level
Page 7
Pulmonary Edema
ď Žâ€Ż
A PFO is needed in fetal life
Kizer, J. R. et al. N Engl J Med 2005;353:2361-2372
Page 8
Thrombus in a PFO
Doufekias, E. et al. J Am Coll Cardiol 2008;51:1049-1059
Copyright Š2008 American College of Cardiology Foundation.
Page 9
Incidence from 9 studies (1897-1984)
8762 patients 2262 with PFO 26% incidence Range 17%-35%
40 PFO Incidence %
30 20 10 0 15
40
Age - yrs
Hagen et al. Mayo Clin. Proc. 59: 17, 1984
PFO Detection
TEE, TTE, TCD
Transesophageal Transthoracic Transcranial
46/111 (41%) patients with PFO 31/111 (28%) patients with PFO 42/111 (38%) patients with PFO
Klotsch et al Neurology 44:1603, 1994
Page 10
75
Echo contrast study of PFO
Bubble Studies
Page 11
PFO Bubble Study
What percent of patients with: …Cryptogenic stroke …Migraine …DCS
Have a PFO? What percent of patients with a PFO have …Cryptogenic stroke ? …Migraine ? …DCS ?
Page 12
PFO prevalence
PFO +
Stroke and PFO
PFO -
Total
Cryptogeni c
31/(77) 9(23)
40
Large Vessel
8/(26) 22(74)
30
Small Vessel
6/(30) 14(70)
20
Emboli c
5(26)
14(74)
19
0
2
2
Misc
Klotsch et al Neurology 44:1603, 1994
Page 13
ď Žâ€Ż
PFO and Stroke
The risk of recurrent stroke was: 2.3 % with PFO alone 15.2 % with both PFO and ASA 4.2 % with neither. 0 % with ASA alone.
Mas, et. al. NEJM 345:1740-1746, 2001
Recent Percutaneous Closure Registries Stroke Recurrence Hung Windecker Sievert Wahl Martin Braun Sommer
n=63 n=80 n= 281 n = 152 n=110 n=276 n=259
3.2 % 3.4% 3.1 % 4.9% 0.9 % 1.7 % 1.2%
Total: n = 1,221 pts (mean age 48 yrs ) Average recurrence
Page 14
2.4%
Migraine Headaches
MIDAS = migraine disability assessment score
Experimental Divers NEDU 88 divers, 444 dives Extending air no decompression limits DCS II in 6/88
Latson GW et. al. UHM, 2008
Page 15
Navy PFO study
Experimental Divers 100%
Percent of Divers
PFO+ PFO80%
60%
40%
20%
0%
control
DCS
Page 16
Experimental Divers 100%
100%
control
DCS
Percent of PFOs
Percent of Divers
control
80%
60% 40%
20%
0%
GR 0
GR I
GR II
GR III
Decompression
# Divers # PFO % PFO
None 109 26 24
60% 40% 20% 0% GR I
GR II
Sickness and PFO
early 50 33 66*
DCS
80%
late 35 9 26
limb skin 20 14 3 12 15 86*
109 sport divers with no DCS, 50 sport divers with DCS < 30 mins 35 sport divers with DCS > 30 mins Wilmshurst et al, 1990
Page 17
GR III
Decompression
Sickness and PFO
26/78 DIVERS WITH PFO and NO DCS Professional
sport
Number
10
16
Age
35.9
32.7
Diving yrs.
12.8
7.5
No. Dives
650
236 Cross et al. BMJ 304:481, 1992
Cutis Marmorata
Page 18
DCS and PFO DCS Type
1+ Shunt
2+ Shunt
Cerebral (20)
2(10)
14(70)
Control ( 2 0 )
2(10)
3(15)
Spinal ( 1 7 )
1(6)
5(29)
Control ( 1 6 )
2(13)
6(37)
1+
2+ Germonpre et al JAP 84: 1622, 1998
European Sport Divers
Torti, et al. European Heart Journal 2004 25, 1014
Page 19
European Sport Divers
Prevalence
30% 25% 20% 15% 10% 5% 0% pfo1
pfo2
pfo3
pfotot
PFO grade Torti, et al. European Heart Journal 2004 25, 1014
European Sport Divers PFO
No PFO
Total Divers
63
167
Total Major DCI
18
10
DCI Sx > 24 hrs
11
6
Recompression Rx
12
3
Torti, et al. European Heart Journal 2004 25, 1014
Page 20
European Sport Divers Self Reported Symptoms Minor DCI
Major DCI
bends
limb weakness
cutaneous erythema
cutaneous sensory level
extreme fatigue
bowel/bladder dysfunction
headache
paresis or paraplegia
dizziness
blurred vision
paresthesias
dysarthria
tinnitus
amnesia for the event hemiplegia loss of consciousness Torti, et al. European Heart Journal 2004 25, 1014
European Sport Divers
Torti, et al. European Heart Journal 2004 25, 1014
Page 21
DCS
Risk MILITARY
SPORT
COMM
ALL
2,578K
43K
3,269K
Total Dives
648K
Total DCS
172
878
152
1202
86
649
9
744
2.65
3.41
35.3
3.68
DCS II 1.33
2.52
2.09
2.28
Type II DCS †
Incidence DCS
†
t
incidence per 10,000 dives Bove AA. Undersea and Hyperbaric Med. 25:175, 1998
Type II DCS Risk Risk
R/1,000 dives
P(DCS+/PFO+)
0.00047
0.47
P(DCS+/PFO-)
0.00019
0.19
RATIO = 2.52 P < 0.001 Bove AA. Undersea and Hyperbaric Med. 25:175, 1998
Page 22
PFO Closure Device
Percutaneous Closure of a Patent Foramen Ovale
Kizer, J. R. et al. N Engl J Med 2005;353:2361-2372
Page 23
Percutaneous Closure
PFO
Conclusions Overall DCS risk is increased about 2 fold with moderate size PFO, 4 fold with large PFO Absolute risk is small (0.047%) Screening for PFO is not indicated PFO is not a contraindication for diving Echo should be done if DCS or AGE is unexplained
Page 24
The PFO in Space Common Problems with Decompression
Nitrogen Supersaturation Occurs on Ascent Critical Supersaturation Produces bubbles DCS Occurs in Aviation and Diving
The PFO in Space 16 14
PRESSURE -psi
12 10 8 6 4 2 0 0
5
10 15 20 25 30 ALTITUDE - Thousands of feet
Page 25
35
40
The PFO in Space 1.0
atm.
0.9 0.8
8
0.7
Pressure
0.6
18
0.5 0.4 0.3
29
0.2 0.1 0.0 0
20
40
60
80
100
Altitude - 1000 ft
The PFO in Space 0.25
PO2
0.20
FiO2 = 0.21
0.15 0.10 0.05 0.00 0
20
40
60
Altitude - 1000 ft
Page 26
80
100
The PFO in Space
The PFO in Space
4.3 PSI, 0.3 ATA 100% Oxygen PO2 = 228 mmhg
Page 27
The PFO in Space 4.3 PSI 4 hrs, light exercise 100%
% DCS
80% 60% 40% 20% 0% 0
5
10
15
20
Prebreath hours
The PFO in Space ratio for 320 min tissue 2.50 10.2 PSI base 14.7 PSI base
TR
2.00 1.50 1.00 0.50 0.00 0
5
10
HRS
Suit Pressure = 4.3 PSI
Page 28
15
25
Space Station DCS Mitigation PHASE II
15
P
amb
-
psi
20
10 5 0 0
50
100
150
200
250
300
350
time - min
Tissue
N2
PP N2 - ATA
1 0.8 0.6 0.4 0.2 0 0
50
100
150
200
250
300
350
time - min
• Pilmanis et al., 1996; 8 cases of LVGE ❏ ❏ ❏ ❏
8/2470 subject-exposures with LVGE; all males All 8 Had Grade 4 VGE 7 of 8 had DCS (no serious symptoms) 7 of 8 evaluated for PFO 5 TEE: 1 Sinus venosus; 1 PFO; 3 negative PFO 2 TTE: 2 PFO 1 not evaluated
Page 29
Complications of Closure Type Fail placement Peric effusion Late complic Early Compl Late CVA Residual shunt Early compl Fail Placement Major compl Lte complications Late shunt Displacement/surg Tamponade Vascular Late compl AF early Visual early TIA Proced compl Failed close Early compl TIA early Recurrent events
% 6.25 3.125 12.5 12 6 6.4 5.1 6 3 3 33 1 1 4 4 8 6 1 6.6 26 7 3 16
No Pts 32
ASD 26
PFO 6
33
33
78
78
100
100
50
Purcell
140
140
Anzola 1 year
272
272
Alameddine
81
Khositseth
103
50
Comment Source Urgent surg Ridder 5 yr centesis surgery Surg study Gasiavelis 8.5 yr Ortho deox Guerin AF, clot,fist Herrmann 6 mo
22
29 months
The PFO in Space PFO
Conclusions Overall DCS risk is increased about 2 fold Absolute risk is small PFO is not a contraindication to space flight Prospective Studies are needed to assess risk for DCS with a PFO in space flight
Page 30