8,854 m or (29,050 ft) Tenzing Norgay, Edmund Hillary ...€¦ · No. PY6.4 & 6.5 (Respiratory...
Transcript of 8,854 m or (29,050 ft) Tenzing Norgay, Edmund Hillary ...€¦ · No. PY6.4 & 6.5 (Respiratory...
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•Elevation : 8,854 m or (29,050 ft)
•First ascent : May 29, 1953
•First ascenders: Tenzing Norgay, Edmund Hillary
•Mountain range: Himalayas, Mahalangur Himal
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Dr. Jitendra Patel (MBBS, MD, ACME, Ph.D…)
Medical Educator, Researcher & Academic Administrator
Associate Professor, Department of Physiology
Email: [email protected] Web: www.esphys.weebly.com
Competency
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No. PY6.4 & 6.5 (Respiratory Physiology)
CompetencyDescribe and discuss the physiology of high altitude. Describe and discuss the oxygen therapy and acclimatization.
D/L/Core K/KH/Y
AM Written/Viva voce
Integration No
Imp. Concept Problem and its solution in HAP
Phy. TriviaDefence Institute of Physiology & Allied Sciences (DIPAS)
OUTLINE
• Introduction
• Basic concept & problem
• Clinical syndrome
• Physiological compensatory mechanism
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Introduction
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ALTITUDE TYPEFROM SEA-LEVEL
(In feet)
HIGH 8,000 – 12,000
VERY HIGH 12,000 – 18,000
EXTREMELY HIGH Above 18,000
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My definition of Altitude (life)
Altitude = Goal/Attitude
Satisfaction > Success
SIGNIFICANT ATMOSPHERIC PRESSURE VARIATION WITH ALTITUDE:
ALTITUDE PRESSURE
(FEET) ( mm of Hg) (Atmospheric unit)
0 760 1
18,000 380 1/2
34,000 190 1/4
48,000 95 1/8
63,000 47 1/16
Basic Concept
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• Human body is specifically designed in such a way
that it delivers adequate O2 to the tissues only
when oxygen is supplied at a pressure close to the
sea-level (P = 760 mm Hg PO2 =159 mm Hg).
• So, at high altitude there is hypoxic hypoxia
tissue oxygenation suffers physiological
derangements.
“Connecting a 24 volt motor to a 6 volt battery” :P
Basic Problem
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• Decreased pO2
• Increased Volume
• Decreased temperature
• Effect of light rays
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ALTITUDE LEVEL
INSPIRED AIR PO2
Hb-SATURATION EFFECTS
Feet (meter) In mm of Hg in % Stages (if any)
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ALTITUDE LEVEL
INSPIRED AIR PO2
Hb-SATURATION EFFECTS
Feet (meter) In mm of Hg in % Stages (if any)
0 (sea-level) 160 ~ 97 %NIL
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ALTITUDE LEVEL
INSPIRED AIR PO2
Hb-SATURATION EFFECTS
Feet (meter) In mm of Hg in % Stages (if any)
0 (sea-level) 160 ~ 97 %NIL
Upto 10,000(3,000)
110 ~ 90 %Usually none,
( of indifference)
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ALTITUDE LEVEL
INSPIRED AIR PO2
Hb-SATURATION EFFECTS
Feet (meter) In mm of Hg in % Stages (if any)
0 (sea-level) 160 ~ 97 %NIL
Upto 10,000(3,000)
110 ~ 90 %Usually none,
( of indifference)
10,000 –15,000
(3,000 –4,500)
98 ~ 80 %
Mod. Hypoxic symptomscardiorespiratory manifestaions & early
CNS involvements ( of reaction)
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ALTITUDE LEVEL
INSPIRED AIR PO2
Hb-SATURATION EFFECTS
Feet (meter) In mm of Hg in % Stages (if any)
0 (sea-level) 160 ~ 97 %NIL
Upto 10,000(3,000)
110 ~ 90 %Usually none,
( of indifference)
10,000 –15,000
(3,000 –4,500)
98 ~ 80 %
Mod. Hypoxic symptomscardiorespiratory manifestaions & early
CNS involvements ( of reaction)
15,000 –20,000
(4,500 –6,000)
70 < 70 %Severe hypoxic symp aggravated CNS
involvement (of disturbance)
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ALTITUDE LEVEL
INSPIRED AIR PO2
Hb-SATURATION EFFECTS
Feet (meter) In mm of Hg in % Stages (if any)
0 (sea-level) 160 ~ 97 %NIL
Upto 10,000(3,000)
110 ~ 90 %Usually none,
( of indifference)
10,000 –15,000
(3,000 –4,500)
98 ~ 80 %
Mod. Hypoxic symptomscardiorespiratory manifestaions & early
CNS involvements ( of reaction)
15,000 –20,000
(4,500 –6,000)
70 < 70 %Severe hypoxic symp aggravated CNS
involvement (of disturbance)
Above 20,000 &
onwardsFurther falls below 60 %
Unconsciousness & alarmingdeterioration survival impossible
without supplemental O2 (critical survival altitude)
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Effects depend upon….. (LSD)
1. The level of altitude
2. Rapid or slow ascent
3. Duration of exposure
Acute mountain sickness
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Sea level resident ascending within 1-2 days
1) Acute cerebral edema
2) Acute pulmonary edema
Acute cerebral edema
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Acute cerebral edema…….
• Hypoxia → cerebral VD → ↑ capi. Pressure →
cerebral edema → Headache, nausea,
vomiting, irritability, disorientation,
dysfunction.
High Altitude Pulmonary Edema
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• Rapid ascent usually above 10000 ft.
• Heavy physical work during 1st 3-4 days.
• Mechanism;
– Sympathetic over activity due to hypoxia/Cold
temperature.
– Causes VC – ↑Pulmonary capi hydrostatic pressure.
– Causes pulmonary edema.
Chronic mountain sickness (Monge’s dis.)
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Long Term Residents of High Altitude
↑ ↑ ↑ RBC
↑ ↑ Pulmonary artery pressure (PAP).
Enlargement & failure of right heart.
↓ Systemic arterial pressure.
CCF, Death.
Treatment of high altitude illness
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Individual should be brought to low altitude at the
earliest and rest
Treatment of pulmonary and cerebral oedema:
• O2 therapy
• Diuretics
• Steroids
• Nifedipine
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Physiological responses to high altitude
Acute responses (Accommodation)
Long term responses (Acclimatization)
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Accommodation
• Immediate reflex adjustments of RS & CVS
–Hyperventilation
–Tachycardia
– Increased 2-3 DPG
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Acclimatization
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• “Getting used to…”
• People remaining at high altitudes for days, weeks
or years become more and more acclimatized to
low PO2.
• This causes the hypoxia to cause fewer deleterious
effects on their bodies.
• They can thus work harder at higher altitudes
without hypoxic effects.
Acclimatization…cont
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After a long term exposure to hypoxia
Increase in ventilation;
• Stimulation of respiratory centers by
peripheral chemoreceptors.
Increased RBC count;
• Hypoxia stimulates erythropoiesis.
Acclimatization…cont
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After a long term exposure to hypoxia
Increased TLC & diffusing capacity of lungs;
• ↑Pulmo. Capi. Suface area due to ↑ pulm. Blood volume
• ↑Lung air volume
• ↑Pulm. Arterial pressure
Increased vascularity of the peripheral tissues;
• Angiogenesis
Increased O2 usage by cells despite less pO2.
Natural Acclimatization
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This occurs in people
living from their birth at
high altitudes.
Those living in the Andes
& Himalayan mountains,
for instance.
Acclimatization begins in
them in infancy.
Effects:-
↑chest size
↓ body size
↑ Rt. Heart
↑ O2 delivery to the tissues
(↑Hb)
↑ work capacity (87%)
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Physiology Trivia
Defence Institute of Physiology & Allied Sciences (DIPAS)
Established on 20th September 1962. In India,
research in military physiology was initiated in the year
1950 through a small group of scientists and medical
physiologists within the realm of Defence Science
Laboratory, Delhi.
http://drdo.gov.in/drdo/labs/DIPAS/English/index.jsp?pg
=homebody.jsp
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ANS: C
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ANS: A
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ANS: B
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ANS: B
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ANS: A
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