Normal Values for Pulmonary Hemodynamics at Rest and during Exercise in Man

106

Individuals susceptible to high-altitude pulmonary oedema (HAPE) are characterised by an abnormal increase of pulmonary artery systolic pressure (PASP) in hypoxia and during normoxic exercise, reduced hypoxic ventilatory response, and smaller lung volume.In 37 mountaineers with well-documented altitude tolerance, it was investigated whether any combination of these noninvasive measurements, including exercise in hypoxia, could improve the identification of HAPE-susceptible subjects at low altitude.HAPE-susceptible subjects showed a significant higher increase of PASP during hypoxia at rest (48¡10 mmHg) compared with controls (38¡3 mmHg), as well as during normoxic exercise (57¡14 versus 38¡7 mmHg) and hypoxic exercise (69¡13 versus 49¡8 mmHg). PASP could not be assessed in three and eight subjects during normoxic or hypoxic exercise, respectively, due to insufficient Doppler profiles or systemic arterial hypertension. Sensitivity (77-94%) and specificity (76-93%) were not significantly different between the various testing conditions. Additional assessment of hypoxic ventilatory response and lung function parameters did not improve identification of HAPE-susceptible subjects in a multivariate analysis.Due to the greater number of missing values in pulmonary artery systolic pressure measurements during hypoxic exercise, it was concluded that pulmonary artery systolic pressure measurements at rest during hypoxia or exercise in normoxia are most feasible for the identification of high-altitude pulmonary oedema-susceptible subjects.KEYWORDS: Doppler echocardiography, exercise, hypoxia, hypoxic ventilatory response, lung volumes, pulmonary artery pressure H igh-altitude pulmonary oedema (HAPE) is a noncardiogenic pulmonary oedema that occurs at an altitude of 4,559 m in up to 6% of otherwise healthy unselected subjects [1]. Altitude, speed of ascent, pre-acclimatisation and, above all, individual susceptibility are determinants for its occurrence. The combination of fast ascent and susceptibility to HAPE increases the incidence of HAPE at 4,559 m to ,60% [1]. Since HAPE is a life-threatening condition, it would be helpful to identify HAPE-susceptible subjects at low altitude, particularly in those with no previous altitude exposure.It has been widely demonstrated that increased hypoxic pulmonary vasoconstriction leading to abnormally high pulmonary artery pressure is the major contributor in the development of HAPE. The crucial role of high pulmonary artery pressure is confirmed by elevated pulmonary artery pressures in patients with HAPE [2-4], enhanced pulmonary vasoconstrictive response in HAPE-susceptible subjects to acute hypoxia [5][6][7][8] or exercise in normoxia [6,7,9]. It is also confirmed by the fact that interventions decreasing pulmonary artery pressure are effective in the treatment [10, 11] and prevention [4] of HAPE. A previous study suggested that pulmonary artery systolic pressure (PASP) does not exceed 40 mmHg in healthy subjects during acute hypoxic exposure (inspiratory oxygen fractio...

Section: Pulmonary Vascular Responsesupporting

confidence: 87%

Section: Pulmonary Vascular Responsesupporting

confidence: 84%

Identification of individuals susceptible to high-altitude pulmonary oedema at low altitude

Dehnert

Grünig²,

Mereles³

et al. 2005

106

“…1) [8][9][10][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. After the exclusion of individuals with prospectively defined implausible data, 222 subjects (147 males, 33 females, 42 sex not available) were analysed.…”

Section: Resultsmentioning

confidence: 99%

Pulmonary vascular resistances during exercise in normal subjects: a systematic review

Kovàcs

Olschewski²,

Berghold³

et al. 2011

210

161

The physiological range of pulmonary vascular resistance (PVR) and total pulmonary resistance (TPR), and the impact of exercise, age and posture have been a matter of debate for many years.We performed a systematic literature review including all right heart catheterisation data where individual PVR and TPR of healthy subjects both at rest and exercise were available. Data were stratified according to age, exercise level and posture.Supine resting PVR in subjects aged ,24 yrs, 24-50 yrs, 51-69 yrs and o70 yrs was 61¡23, 69¡28, 86¡15 and 90¡39 dyn?s?cm -5 , respectively. Corresponding TPR was 165¡50, 164¡46, 226¡64 and 223¡45 dyn?s?cm -5, respectively. During moderate exercise in subjects aged f50 yrs, an 85% increase in cardiac output was associated with a 25% decrease in TPR (p,0.0001) and a 12% decrease in PVR (p,0.01). At 51-69 yrs of age there was no significant decrease in TPR and PVR. In individuals aged o70 yrs TPR even increased by 17% (p50.01), while PVR did not change significantly. At higher exercise levels, TPR decreased in all age groups. In the upright position, based on a limited number of data, resting TPR and PVR were higher than in the supine position and decreased more prominently during exercise, suggesting the release of resting pulmonary vasoconstriction.These data may form a basis to define normal PVR at rest and exercise.

“…Influence of sex, geographical origin, exercise method and position on Ppa Sex and the geographical origin of the data did not significantly influence resting and exercise P pa values (online data supplement, tables G-I) [13,14,16,18,19,29,35,39,43,47].…”

Section: Pulmonary Arterial Pressure During Exercisementioning

confidence: 99%

Pulmonary arterial pressure during rest and exercise in healthy subjects: a systematic review

Kovàcs

Berghold²,

Scheidl³

et al. 2009

905

639

According to current guidelines, pulmonary arterial hypertension (PAH) is diagnosed when mean pulmonary arterial pressure (Ppa) exceeds 25 mmHg at rest or 30 mmHg during exercise. Issues that remain unclear are the classification of Ppa values ,25mmHg and whether Ppa .30 mmHg during exercise is always pathological.We performed a comprehensive literature review and analysed all accessible data obtained by right heart catheter studies from healthy individuals to determine normal Ppa at rest and during exercise. Data on 1,187 individuals from 47 studies in 13 countries were included. Data were stratified for sex, age, geographical origin, body position and exercise level.Ppa at rest was 14.0¡3.3 mmHg and this value was independent of sex and ethnicity. Resting Ppa was slightly influenced by posture (supine 14.0¡3.3 mmHg, upright 13.6¡3.1 mmHg) and age (,30 yrs: 12.8¡ 3.1mmHg; 30-50 yrs: 12.9¡3.0 mmHg; o50 yrs: 14.7¡4.0 mmHg). Ppa during exercise was dependent on exercise level and age. During mild exercise, Ppa was 19.4¡4.8 mmHg in subjects aged ,50 yrs compared with 29.4¡8.4 mmHg in subjects o50 yrs (p,0.001).In conclusion, while Ppa at rest is virtually independent of age and rarely exceeds 20 mmHg, exercise Ppa is age-related and frequently exceeds 30 mmHg, especially in elderly individuals, which makes it difficult to define normal Ppa values during exercise.