Alterations in serum and extracellular electrolytes during high-altitude exposure.

Hannon, John P.; Chinn, Kenneth S. K.; Shields, J. L.

doi:10.1152/jappl.1971.31.2.266

Cited by 27 publications

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“…Increased ventilation causes respiratory alkalosis, which is not fully compensated above 3000 to 4000 m and may be accompanied by a fall of serum potassium. 99 This may be of particular relevance to patients on diuretics. Cold requires heat production, and this places further demands on the heart and circulation.…”

Section: High-altitude Tolerance Of Patients With Cardiovascular Diseasementioning

confidence: 99%

Effect of Altitude on the Heart and the Lungs

2007

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T his review focuses on the effects of altitude exposure from 1 to several days or weeks as occurs in tourists, trekkers, and mountaineers who visit high altitude and normally reside near sea level. We briefly review the acute physiological adjustments and early acclimatization that occur in the cardiovascular system and the lungs of healthy individuals. These ensure life-sustaining oxygen delivery to the tissues despite a reduction in the partial pressure of inspired oxygen between 20% and 60% at 2500 and 8000 m, respectively. One of the acute adjustments, hypoxic pulmonary vasoconstriction (HPV), may be disadvantageous in those with a vigorous response and lead to 2 potentially lethal illnesses, high-altitude pulmonary edema (HAPE) and subacute mountain sickness (SAMS), which we present in more detail. Finally, on the basis of knowledge about the acute physiological adjustments and acclimatization and, when available, a review of the literature, we discuss the highaltitude tolerance of patients with coronary artery disease, congestive heart failure, arrhythmias, systemic hypertension, and pulmonary hypertension. Effects of Exposure to High Altitude on the Normal Cardiovascular System CirculationThe major effects of acute hypoxia on the heart and lung are shown in Figure 1. Hypoxia directly affects the vascular tone of the pulmonary and systemic resistance vessels and increases ventilation and sympathetic activity via stimulation of the peripheral chemoreceptors. 1 Interactions occur between the direct effects of hypoxia on blood vessels and the chemoreceptor-mediated responses in the systemic and pulmonary circulation. Unraveling the underlying mechanisms of the hypoxic vasodilatation of systemic arterioles is an active area of research. Several mechanisms appear to regulate local oxygen delivery according to the needs of the tissues 2,3 ; for instance, the release of ATP from red blood cells and the generation of NO by various ways appear to regulate local oxygen delivery according to the needs of the tissue. These mechanisms may decrease with prolonged stay at high altitude when oxygen content of the blood increases because of ventilatory acclimatization, an increase in hematocrit associated with plasma volume reduction, and an increase in red blood cell mass due to erythropoiesis.Peripheral chemoreceptor afferent activity rises hyperbolically as hypoxia increases. 4 Ventilation and sympathetic activity are augmented, as demonstrated by increased urinary and plasma concentration of catecholamines 5 and skeletal muscle sympathetic activity. 6 With exposure over days to weeks, the sensitivity of the peripheral chemoreceptors to hypoxia increases, leading to further enhancement of ventilation (ventilatory acclimatization). This presumably also accounts for the further increase of sympathetic activity documented by microneurography after 3 weeks at 5200 m 6 and elevated catecholamines in urine and plasma. 5 As shown in Figure 1, there is antagonism between the direct effects of hypoxia on the resistance vessels ...

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Section: High-altitude Tolerance Of Patients With Cardiovascular Diseasementioning

confidence: 99%

Effect of Altitude on the Heart and the Lungs

2007

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“…F o r example, after one week on Pikes Peak men subjected to essentially the same exp e r i m e n t a l conditions attending this study exhibited a m e a s u r e d , a r t e r i a l b i c a rbonate loss of 6.0 m e q / 1 (Hannon, Chinn, and Shields, 1970). This is approximately one-half the 12.1 m e q / 1 observed after the s a m e t i m e interval in women.…”

Section: Discussionmentioning

confidence: 49%

“…Other sex differences appear when the data reported here are compared to those contained in the aforementioned study of soldiers (Hannon, Chinn and Shields, 1970}. In m a l e s , the lost s e r u m bicarbonate is entirely replaced by i n c r e a s e s in chloride, phosphate and proteinate, while in women partial compensation is achieved through a reduction in sodium and to a much m o r e limited extent, potassium.…”

Section: Discussionmentioning

confidence: 65%

“…Probably, in view of the s i m i l a r i t y of the p l a s m a volume changes in the two sexes, they would exhibit the same response as men. And if this proves true they, like men (Hannon, Chinn and Shields, 1970} show marked reductions in total e x t r a c e l l u l a r electrolyte levels, principally sodium, chloride and bicarbonate, during the acute stages of altitude exposure.…”

Section: Discussionmentioning

confidence: 97%

“…Such secondary c o m p e n s ations can take either or both of two f o r m s : the concentration of one or m o r e cations may be reduced or the concentration of one or m o r e anions may be i n c r e a s e d . In a previous study of soldiers (Hannon, Chinn and Shields, 1970) exposed to an e l evation of 4,300 m for two weeks, the l a t t e r r e s p o n s e was found to predominate. In the investigation reported h e r e , s i m i l a r m e a s u r e m e n t s w e r e made in college women students exposed to the same elevation but for a much longer period of time.…”

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confidence: 80%

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Alterations in the serum electrolyte levels of women during high altitude (4,300 m) acclimatization

Hannon

Harris²,

Shields

1970

Int J Biometeorol

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Compensation for high altitude r e s p i r a t o r y alkalosis, as shown by the early work of Sundstroem (1919a, b), Hasselbalch and Lindhard (1915), Haggard and Henderson (1920), and Haldane, Kellas and Kennaway (1919) includes a d e c r e a s e in a mmonia excretion and an i n c r e a s e in bicarbonate excretion. Together these r esponses c o n s e r v e body hydrogen ion. The enhanced excretion of bicarbonate, howe v e r , soon leads to its depletion f r o m the s e r u m and other body fluids, a condition which p e r s i s t s for as long as the individual r e m a i n s at high altitude (Hurtado and A s t e -S a l a z a r , 1948). This reduction in bicarbonate content c o m p r o m i s e s the n o rmal ionic balance of the body, and secondary compensations must be initiated in o r d e r to maintain the equality of cations and anions. Such secondary c o m p e n s ations can take either or both of two f o r m s : the concentration of one or m o r e cations may be reduced or the concentration of one or m o r e anions may be i n c r e a s e d . In a previous study of soldiers (Hannon, Chinn and Shields, 1970) exposed to an e l evation of 4,300 m for two weeks, the l a t t e r r e s p o n s e was found to predominate. In the investigation reported h e r e , s i m i l a r m e a s u r e m e n t s w e r e made in college women students exposed to the same elevation but for a much longer period of time. METHODSThe subjects of this study w e r e eight students f r o m the U n i v e r s i t y of Missouri (elevation 230 m) who lived and worked on the s u m m i t of Pikes Peak (elevation 4,300 m}. Details concerning their selection as well as the general experimental conditions attending the study a r e reported e l s e w h e r e (Harmon, Shields and H a rr i s , 1969a, b). Briefly, the initial low altitude m e a s u r e m e n t s w e r e made in e a rly June in laboratory space in the Physiology Department of the U n i v e r s i t y of M i ssouri. The subjects w e r e then flown to Denver and taken by automobile to the summit of Pikes Peak. At high altitude the m e a s u r e m e n t s w e r e repeated in a mobile field l a b o r a t o r y after 1, 7, 30, and 65 days of exposure. Final m e a s u r ements w e r e made in September, two weeks after the subjects had r e t u r n e d to M i ss ouri.Identical p r o c e d u r e s and methods w e r e used at both low and high altitude. A f t e r an overnight fast, each subject was brought into the laboratory where she r e s t e d in a supine position for one hour. At the end of this period a blood s a m p l e was drawn, without s t a s i s , f r o m a superficial a r m vein. The sample was allowed to clot for 30 rain, after which the s e r u m was r e m o v e d , frozen and s t o r e d in sealed glass containers for l a t e r analysis.

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Ventilatory Control at High Altitude

Weil

1986

Comprehensive Physiology

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FIG. 2. Oxygen-tension (P4) cascade at low and high altitude.At high altitude, fall in P, for each step from tracheal or inspired air to venous circulation is decreased. One of the greatest decreases is that from inspired to alveolar air, which largely reflects increased ventilation at high altitude. [Adapted from Hurtado (105).] CHAPTER 21: VENTILATORY CONTROL AT HIGH ALTITUDE 705 /Y lr pace, pace, FIG. 3. Contrast of acid-base and oxygenation effects on ventilatory response to CO2. Acid-base alterations shift curve position (intercept) with little or no change in slope, whereas changes in O2 tension (P ) mainly influence the slope. P b , , arterial partial pressure of'%oz.

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Alterations in serum and extracellular electrolytes during high-altitude exposure.

Cited by 27 publications

References 0 publications

Effect of Altitude on the Heart and the Lungs

Effect of Altitude on the Heart and the Lungs

Alterations in the serum electrolyte levels of women during high altitude (4,300 m) acclimatization

Ventilatory Control at High Altitude

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