Out of 43 studies, 29 included healthy subjects, nine included patients with lung disease, four included patients with heart disease, seven included patients with SCI, three included patients with neuromuscular diseases, and four included patients with obesity. Additional file 2 : Table S2 summarizes only the statistically significant findings for each relevant outcome variable, according to position, for each of the populations studied. The association between FVC and body position in healthy subjects was investigated in 13 studies [ 3 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ].
There was a clinical and statistically significant increase in FVC in sitting vs. In a smaller number of studies there was no change between standing and sitting [ 19 ], sitting and supine [ 17 , 21 , 28 ] or sitting and RSL or LSL [ 21 ], and one study [ 22 ] found a decrease in FVC from sitting to standing that was statistically but not clinically significant.
Thus, in the majority of studies the more upright position was associated with increased FVC. Four studies included subjects with lung disease [ 29 , 30 , 31 , 32 ].
Among asthmatic patients in one study FVC increased significantly from supine to standing [ 30 ]; however, there was no significant difference between standing and sitting or between sitting and supine, RSL, or LSL. Another study reported a statistically and clinically significant increase in FVC in standing vs.
Among obese asthmatic patients [ 32 ], and among patients with chronic obstructive pulmonary disease COPD [ 29 ], no difference was found in FVC between standing and sitting. Three studies included subjects with congestive heart failure CHF [ 18 , 21 , 27 ]. In one study, FVC was reported ml higher in sitting vs. Six studies included patients with SCI [ 17 , 33 , 34 , 35 , 36 , 37 ].
The effect of body position on FVC depends on the level and extent of injury. Other studies [ 35 , 36 , 37 ] did not find significant differences in FVC for patients with SCI in a pooled group of all levels of injury for these positions. However, in patients with cervical SCI, as well as those with thoracic injury in one study [ 36 ], there was an increased FVC in the supine vs. The differences did not always reach statistical significance. Nevertheless, it is important to note that in these debilitated patients with SCI, even a small change in FVC is probably clinically significant.
Three studies evaluated patients with neuromuscular diseases [ 25 , 34 , 38 ]. In patients with myotonic dystrophy and in those with amyotrophic lateral sclerosis ALS , there was a clinically and statistically significant decrease in FVC from sitting to supine [ 25 , 34 , 38 ]. In subjects with obesity mean BMI In healthy subjects, FEV1 was reported to be higher in sitting vs.
One study [ 22 ] reported a decrease of ml in FEV1 from sitting to standing, which is statistically but not clinically significant. Among asthmatic patients, FEV1 was higher in the standing vs. Another study in asthmatic patients reported FEV1 to be higher in standing vs. Among obese asthmatic patients and those with COPD, there was no significant difference in FEV1 between standing and sitting [ 29 , 32 ].
In one study among all subjects with SCI, FEV1 was not significantly influenced by moving from sitting to supine [ 35 ], but patients with cervical injuries showed a tendency for increased FEV1 in the supine vs.
Along the same vein, another study [ 36 ] found an increase is FEV1 in the sitting vs. Although the differences between positions were not statistically significant, the effect of level of injury was statistically and clinically significant.
In another study [ 33 ], FEV1 was higher in supine vs. Another group [ 37 ] reported no significant change in FEV1 between the sitting and supine positions for a pooled group of patients with SCI, but in the subgroup of patients with incomplete motor injury and in those with incomplete thoracic motor injury there was a decrease in the supine position.
In patients with myotonic dystrophy, FEV1 decreased from sitting to supine [ 38 ]. Among those with obesity, FEV1 was higher in sitting vs. In another study among obese patients, there was no difference in FEV1 between standing and sitting [ 32 ]. LSL [ 19 ], and in standing vs. Other studies found no difference between sitting and supine [ 18 , 24 , 27 ] or standing, sitting, and supine [ 42 ]. The effect of body position on vital capacity was evaluated in six studies of healthy subjects [ 21 , 24 , 28 , 39 , 43 , 44 ].
In most studies no difference was reported between sitting and supine [ 21 , 24 , 28 , 43 ] or between sitting and RSL or LSL [ 21 ]. One study [ 39 ] found that VC was higher in the sitting vs. However, another study [ 44 ] found that VC was higher in the supine vs. In patients with spinal cord injury, VC was higher in the supine vs. In subjects with obesity, no difference in VC was reported between the sitting and supine positions [ 41 , 43 ]. PEF in different body positions was evaluated in 13 studies [ 3 , 22 , 23 , 24 , 31 , 33 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ].
Eight studies evaluated only healthy adults [ 3 , 22 , 23 , 24 , 45 , 48 , 50 , 51 ], three evaluated healthy subjects and patients with COPD or asthma [ 31 , 46 , 49 ], one included adult cystic fibrosis patients [ 47 ], and one included subjects with SCI [ 33 ].
Nine studies that compared standing or sitting positions vs. Three of six studies comparing the standing and sitting positions found higher PEF in standing [ 46 , 50 , 51 ] and one reported higher PEF in sitting [ 22 ]. However, it is most likely that none of the differences reported in PEF are clinically significant. FRC was evaluated using helium dilution in five studies [ 27 , 41 , 43 , 52 , 53 ]. Among healthy subjects, FRC was higher in standing [ 53 ] and in sitting [ 27 , 43 ] vs.
However, the difference in sitting vs. Another study [ 52 ] involving subjects with mild-to-moderate obesity mean BMI 32 , reported that FRC was significantly higher both statistically and clinically in sitting vs.
Two studies that evaluated TLC using helium dilution in healthy subjects [ 43 ] and in subjects with obesity [ 41 , 43 ] found no statistically significant difference between the sitting and supine positions. Two studies that evaluated RV using helium dilution in healthy subjects [ 43 ] and those with obesity [ 41 , 43 ] found no statistically significant difference between sitting and supine.
Six studies investigated the association between body position and PEmax in healthy subjects [ 3 , 28 , 39 , 46 , 54 , 55 ]. PEmax was higher in standing vs. RSL in patients with cystic fibrosis [ 47 ].
The differences were not clinically significant. In healthy subjects, PImax was improved in sitting vs. However, other studies found no difference in PImax in sitting vs. In subjects with chronic SCI, no significant change was seen in PImax between sitting and supine, with the exception of a subgroup of patients with complete thoracic motor paresis where there was statistically and clinically significant improvement in sitting [ 37 ].
Seven studies evaluated the effect of body position on diffusion capacity; six included healthy subjects [ 18 , 20 , 21 , 24 , 56 , 57 ], three included patients with CHF [ 18 , 21 , 58 ], and one included COPD patients [ 57 ]. Among healthy subjects, two studies [ 24 , 56 ] found statistically and clinically significant improvement in DLCO in supine vs. One study [ 18 ] found DLCO to be higher in the sitting vs.
One study [ 21 ] reported higher DLCO in sitting vs. Three studies investigated diffusion capacity in patients with CHF [ 18 , 21 , 58 ]. One study [ 58 ] found that postural changes from the supine to sitting positions induced different responses in diffusion capacity. In some patients diffusion capacity improved in the sitting position and others showed no change or a decline.
On the average no statistically significant difference was found between the two positions. The authors attributed the difference in responses to variations in pulmonary circulation pressures.
Another study [ 18 ] found no significant difference in diffusion capacity between the sitting and the supine positions. Side-lying was reported to reduce DLCO in comparison to sitting in the third study [ 21 ]. Most studies in this systematic review of 43 papers evaluating the effect of body position on pulmonary function found that pulmonary function improved with more erect posture in both healthy subjects and those with lung disease, heart disease, neuromuscular diseases, and obesity.
In patients with SCI, the effect is more complex and depends on the severity and level of injury. In contrast, diffusion capacity, as assessed by DLCO, increases in the supine position in healthy subjects while the effect in CHF patients is thought to depend upon pulmonary circulation pressure.
Decreased FVC in more recumbent positions may reflect both increased thoracic blood volume due to gravitational facilitation of venous return, which is more important in patients with heart failure, as well as cephalic displacement of the diaphragm due to abdominal pressure in the recumbent positions, which is more important in obese subjects [ 59 ]. In side-lying positions, even though only the dependent hemi-diaphragm is displaced, the effect on FVC appears to be similar to that observed in a supine position [ 59 ].
Other factors that may contribute to lower FVC values in side-lying positions include increased airway resistance and decreased lung compliance secondary to anatomical differences between the left and right lungs, as well as shifting of the mediastinal structures [ 20 ]. FEV1 was also higher in erect positions. Recumbent positions limit expiratory volumes and flow, which may reflect an increase in airway resistance, a decrease in elastic recoil of the lung, or decreased mechanical advantage of forced expiration, presumably affecting the large airways [ 20 ].
In asthmatic patients the increase in FVC while standing might be due to the increased diameter of the airways in this position [ 30 ]. In patients with CHF the lungs are stiff and heavy, and the heart is large and heavy, increasing the negative effects of lung-heart interdependence [ 60 ]. As cardiac dimension increases, lung volume, mechanical function, and diffusion capacity decrease [ 61 , 62 ]; thus, the heart weighs on the diaphragm while sitting and on one of the lungs while in a side-lying position.
This influences the ability of the lungs to expand laterally but allows the diaphragm to descend and the lungs to expand inferiorly. In side-lying positions, the heart weighs on one lung, compressing both the airways and lung parenchyma, leading to a reduction in FEV1 and FVC due to airway compression [ 21 ]. Both elastic reduced lung compliance and resistive loads are simultaneously increased in the supine position in CHF patients [ 63 ].
FVC is thus an important clinical tool for assessment of diaphragmatic weakness in patients with neuromuscular diseases [ 64 ]. In patients with ALS, supine FVC is a test of diaphragmatic weakness [ 65 ] that predicts orthopnea [ 25 ] and prognosis for survival [ 66 , 67 ]. The diaphragm increases its inspiratory excursion in the supine position because its muscle fibers are longer at end expiration, and they operate at a more effective point of their length-tension curve [ 69 , 70 , 71 ].
This mechanism is especially important in patients for whom the diaphragm is the main muscle for breathing, since their intercostal and abdominal muscles are inactive due to SCI. FRC was reported to increase in upright positions in healthy subjects [ 27 , 43 , 53 ] and in patients with mild-to-moderate obesity [ 41 , 52 ]. Changing from a supine to an upright position increases FRC due to reduced pulmonary blood volume and the descent of the diaphragm. This may change the point in which tidal breathing occurs in the volume-pressure curve, which leads to increased lung compliance, and thus an identical pressure change would produce a greater inspired volume if there is no change in respiratory drive [ 53 ].
Farha, K. Asosingh, D. Laskowski, L. Licina, H. Sekiguchi, H. Sekigushi, et al. Pulmonary gas transfer related to markers of angiogenesis during the menstrual cycle. J Appl Physiol , , pp. Donnelly, T. Yang, J. Peat, A. What factors explain racial differences in lung volumes?.
Eur Respir J, 4 , pp. Barone-Adesi, J. Dent, D. Dajnak, S. Beevers, H. Anderson, F. Kelly, et al. Long-term exposure to primary traffic pollutants and lung function in children: cross-sectional study and meta-analysis.
Tabak, A. Spijkerman, W. Verschuren, H. Does educational level influence lung function decline Doetinchem Cohort Study?. Eur Respir J, 34 , pp. Lange, J. Marott, J. Vestbo, T. Ingebrigtsen, B. COPD, 11 , pp. Bryngelsson, M. Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry.
Ups J Med Sci, , pp. Bowatte, C. Lodge, L. Knibbs, A. Lowe, B. Erbas, M. Dennekamp, et al. Traffic-related air pollution exposure is associated with allergic sensitization, asthma, and poor lung function in middle age. J Allergy Clin Immunol, , pp. Rice, W. Li, E. Wilker, D. Gold, J. Schwartz, P. Koutrakis, et al. Extreme temperatures and lung function in the Framingham Heart Study.
Kobayashi, M. Hanagama, S. Yamanda, H. Satoh, S. Tokuda, M. Kobayashi, et al. The impact of a large-scale natural disaster on patients with chronic obstructive pulmonary disease: the aftermath of the Great East Japan Earthquake. Respir Investig, 51 , pp. Dane, H. Lu, J. Dolan, C. Thaler, P. Ravikumar, K. Hammond, et al.
Lung function and maximal oxygen uptake in deer mice Peromyscus maniculatus bred at low altitude and re-acclimatized to high altitude.
Mehari, S. Afreen, J. Ngwa, R. Setse, A. Thomas, V. Poddar, et al. Obesity and pulmonary function in African Americans. Shan, J. Liu, Y. Luo, X. Xu, Z. Han, H. Relationship between nutritional risk and exercise capacity in severe chronic obstructive pulmonary disease in male patients.
Lazovic, S. Mazic, J. Suzic-Lazic, M. Djelic, S. Djordjevic-Saranovic, T. Durmic, et al. Respiratory adaptations in different types of sport. Eur Rev Med Pharmacol Sci, 19 , pp. Hoesein, P. Jong, J. Lammers, W. Mali, O. Mets, M. Schmidt, et al. Contribution of CT quantified emphysema, air trapping and airway wall thickness on pulmonary function in male smokers with and without COPD.
Vargas, M. Pharmacological treatment and impairment of pulmonary function in patients with type 2 diabetes: a cross-sectional study. Biomedica, 36 , pp. Ostrowski, W. Factors influencing lung function: are the predicted values for spirometry reliable enough?.
J Physiol Pharmacol, 57 , pp. Gouna, T. Rakza, E. Kuissi, T. Pennaforte, S. Mur, L. Positioning effects on lung function and breathing pattern in premature newborns. J Pediatr, , pp. Lung function, genetics and socioeconomic conditions. Eur Respir J, 45 , pp. Pugh, C. Jaramillo, K. Leung, P. Faverio, N.
Fleming, E. Mortensen, et al. Increasing prevalence of chronic lung disease in veterans of the wars in Iraq and Afghanistan. Mil Med, , pp. Aldrich, J. Gustave, C. Hall, H. Cohen, M. Webber, R. Zeig-Owens, et al. Lung function in rescue workers at the World Trade Center after 7 years. N Engl J Med, , pp. Galobardes, R. Granell, J. Sterne, R. Hughes, C. Mejia-Lancheros, G.
Davey Smith, et al. Childhood wheezing, asthma, allergy, atopy, and lung function: different socioeconomic patterns for different phenotypes. This neutral position was adopted to avoid extraneous stress on the upper airways. Anthonisen 32 reported that hyperextension of the neck results in an increase in FEV 1 , secondary to elongation and stiffening of the trachea, thereby facilitating air flow.
Conversely, the relaxed recumbent positions examined in our study may effectively shorten and increase the compliance of the airways, such that these positions limit rather than augment maximal forced expiratory effort. Key contributory factors include airway closure and increased pulmonary time constants, both of which are adversely affected in recumbent positions as well as with advancing age. Whether residual effects from a history of smoking affected intraregional differences in 10 subjects is unclear.
Statistically, our results do not support increased inhomogeneity of ventilation in a side-lying position, which would be predicted for an older age group. As described by Otis et al, 35 the concept of pulmonary time constants explains the variations in gas entry into independently ventilated lung units. Increased pulmonary time constants, caused by regional changes in airway resistance and compliance and leading to varying degrees of filling of lung units, can increase the inhomogeneity of ventilation.
Thus, the product of resistance and compliance ie, the pulmonary time constant was greater in a side-lying position than in a sitting position.
Michels et al 37 compared supine and sitting positions and found a similar position-dependent increase in resistance of the respiratory system in a group of adults without cardiopulmonary impairments aged 20 to 67 years. Furthermore, they found that, in a subgroup of young subjects, the increase was more marked in smokers than in nonsmokers.
In addition, the increase was more marked with aging, such that over the age of 50 years, both nonsmokers and smokers demonstrated position-dependent increases in resistance that were of the same magnitude. Behrakis et al 30 suggested that changes in geometry of the upper airways, the aperture of the glottis, or both may contribute to this effect. Michels et al 37 proposed that intrinsic narrowing of the peripheral airways of smokers may be more pronounced in recumbency than in a sitting position.
In light of these considerations, we would anticipate that, in comparison with the sitting position, both left and right side lying would reflect the effects of airway closure and increased pulmonary time constants in conjunction with increased inhomogeneity of ventilation. The fact that our results do not support the findings of other researchers suggests that the effect of body position on the inhomogeneity of ventilation is more variable than for the spirometric measures.
Further study is needed to elucidate differential effects between left and right side-lying positions in older people and whether this effect is accentuated further with factors such as pathology, smoking history, and obesity. The effect of recumbency on diffusing capacity is conflicting in the literature and may reflect age-related factors.
Furthermore, few investigators have targeted an older population for the study of position-related changes. Some authors have reported that DLCO decreases with increasing age. Georges et al 9 attributed the decrease to a decline in Dm the membrane component of DLCO after the age of 40 years and to a decrease in pulmonary capillary blood volume after the age of 60 years. In addition, the anatomic changes associated with aging that affect Dm and pulmonary capillary blood volume may account for the apparent differences in response to a position change as compared with a young population.
Brody and Thurlbeck, 33 for example, described a loss of alveolar surface area, a possible decrease in number of pulmonary capillaries, and an increase in the inner diameter of alveoli, which may affect the mixing of gases by diffusion, as morphologic changes accompanying aging. These changes may reduce the increase of pulmonary capillary blood volume from a sitting position to a recumbent position and may be reflected by a constancy of DLCO between positions. Further study of underlying mechanisms, however, is needed in light of reports that there is no difference in the distribution of pulmonary perfusion between older and younger individuals and little change in pulmonary capillary density.
The similarity of the results for left side lying and right side lying are in agreement with the results of the study by Behrakis et al, 30 one of the few studies comparing lung function in the side-lying positions. These investigators also reported no differences between the side-lying positions for VC, expiratory reserve volume, static and dynamic compliance of the lung, resistance of the lung, or pulmonary time constants in a young group of subjects.
In other studies of the side-lying positions, however, there was either the selection of only one of the side-lying positions, usually right side-lying, 43 — 46 or no reported differentiation between left and right side-lying positions. In younger adults without cardiopulmonary impairments, there is no reason to suspect a difference in lung function between left and right side-lying positions.
In an older population, however, the age-related variation in cardiopulmonary status eg, increase in weight and volume of the heart, 7 , 8 changes in mediastinal compliance may result in differences in function between left and right side-lying positions when compared with a sitting position. Furthermore, in the presence of cardiac or pulmonary conditions, position-related effects on cardiopulmonary status may be accentuated in left and right side-lying positions.
This effect was attributed to the smaller volume of the left lung and compression of the heart on the left lung in left side lying. The morphological changes in the lung that are associated with aging could have a similar effect if the changes are unequally distributed between the left and right lungs; however, there is no evidence to suggest that this is the case. Regional age-related changes in the lung have not been reported, except for a greater degree of emphysematous change considered as a normal part of the aging process in nonsmokers in the lower zones compared with the upper zones of the lung.
Physical therapists should anticipate the physiological effects of side-lying body positions when managing their patients, who may assume such positions for comfort and rest, may be placed in these positions to avoid the negative effects of static body positions, or may be placed in specific therapeutic body positions to augment arterial oxygenation or drain pulmonary secretions. Based on our results, we contend that physical therapists should consider the predictable reduction in lung volumes, lung capacities, and flow rates when placing patients in side-lying positions.
Furthermore, based on a comparison of findings in the literature, we believe that therapists should also consider the less predictable changes in diffusing capacity and homogeneity of ventilation. The adverse effects of recumbent positions can be accentuated by the following factors: cardiopulmonary pathology, age, smoking history, obesity, breathing at low lung volumes, sedation, anesthesia, oxygen, and other pharmacological agents. We believe it is essential that physical therapists be able to identify patients who are at risk to ensure that they are appropriately monitored and that upright positions are encouraged over recumbent positions as much as possible.
In our view, therapeutic recumbent positions should be prescribed judiciously between treatments, and early intervention should be instituted if necessary. In addition, body positioning should not be used injudiciously or without appropriate monitoring, even when administered routinely for comfort and for avoidance of the negative effects of prolonged static positioning. Without due precautions, a patient who is apparently at low risk can readily become a patient who is at high risk.
We believe that the results of studies evaluating interventions for patients with cardiopulmonary disorders eg, measures of lung function and gas exchange have been confounded by the effects of body positioning or body positioning in combination with mobilization , irrespective of the effect of airway clearance. Forced vital capacity and FEV 1 were decreased equally in left and right side-lying positions in older individuals without cardiopulmonary disorders, whereas no corresponding change was observed in diffusing capacity and inhomogeneity of ventilation in either side-lying position.
Conflicting reports in the literature suggest that, compared with spirometric measures, the effect of recumbency on diffusing capacity and homogeneity of ventilation is less predictable and that intervening variables need to be identified. Our results support the idea that body position has a profound effect on lung function and respiratory mechanics. In recumbency, factors contributing to impaired lung function may include external compression of the chest wall, impingement of the abdominal contents on the diaphragm, compression of airways and blood vessels by the heart, and the age-related increase in the mass and volume of the heart.
Further studies are warranted to elucidate the mechanisms of the apparent increase in air flow resistance and reduced lung compliance in side-lying positions. The absence of any change in diffusing capacity in older people without cardiopulmonary impairments supports the idea that side lying may not induce the comparable changes in pulmonary capillary blood volume and venous return that are reported in the literature and that are responsible for the associated increase in diffusing capacity in a supine position.
Although no increase in inhomogeneity of ventilation was observed in our study, this finding does not minimize the well-known detrimental effects of recumbency on functional residual capacity and associated arterial desaturation. Our results have implications for both routine and therapeutic positioning of hospitalized patients with or without cardiac or pulmonary conditions. The physical therapist needs a thorough knowledge of all factors that affect all steps in the oxygen transport pathway in order to prescribe this body positioning efficaciously ie, with maximal benefit and least risk.
This study was supported, in part, by funding from the Canadian Lung Association. We gratefully acknowledge the donation of equipment by Summit Technologies Inc for the study. Dean E. Effect of body position on pulmonary function. Phys Ther. Google Scholar. Ross J , Dean E. Body positioning. In: Zadai C , eds. Positional hypoxemia in unilateral lung disease. N Engl J Med. Body positional effect on gas exchange in unilateral pleural effusion.
The effect of lateral positions on gas exchange in pulmonary disease: a prospective evaluation. Am Rev Respir Dis. A systematic overview and meta-analysis. Zadai C. Pulmonary physiology of aging: the role of rehabilitation.
Topics in Geriatric Rehabilitation. Knudson RJ. Physiology of the aging lung. The Lung. The relationship of age to pulmonary membrane conductance and capillary blood volume.
Levitzky M. Pulmonary Physiology. For all the tests performed, the results for tests performed in the sitting position were consistently higher than those performed in standing or supine positions Table 2 Table 3.
Table 2 Data comparison for results obtained in spirometry while sitting vs. Table 3 Data comparison for results obtained for spirometry in sitting vs. The results show that the highest measurement of pulmonary functions was found when the subject had performed spirometry while sitting.
We had done sitting tests before the standing tests while study done by Pierson et al. However in a study done by Townsend et al. Vilke et al. Considering the significance of the differences found, however, patients who undergo spirometry will have a great chance of giving results susceptible to wrong interpretations, if done in the standing or supine position.
Our study has the limitation of being a cross-sectional study of fewer subjects, limited to healthy subjects between the ages of 19 and Larger studies that use a wider age range in a larger sample size including normal subjects as well as patients with respiratory diseases are further needed. Spirometry should be done in a position in which the reference values which we are using have been derived. Interpretation of spirometric values done in supine position should be done by reducing reference values according to local results after further correlation by larger studies on normal subjects and patients with respiratory diseases.
This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially. Withdrawal Guidlines. Publication Ethics. Withdrawal Policies Publication Ethics. Journal of.
0コメント