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Lira M, Fregonezi G, Marcelino AA, Sarmento A, Resqueti VR. Normal range of values for contractility and relaxation parameters of inspiratory muscles in healthy children: An exploratory study. Pediatr Pulmonol 2020; 55:1512-1520. [PMID: 32297707 DOI: 10.1002/ppul.24779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 04/01/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To estimate normal range of values for the contractility and relaxation parameters of inspiratory muscles and compare them by sex, age, nutritional status and level of physical activity in healthy children. WORKING HYPOTHESIS We hypothesized that healthy children present similar range of values for the contractility and relaxation parameters of inspiratory muscles. STUDY DESIGN Exploratory study conducted between 2017 and 2018. PATIENT-SUBJECT SELECTION Healthy children aged 6 to 11 years without history of respiratory, cardiac, cerebrovascular or neuromuscular disease as well as no nasal congestion, influenza or known septum deviation were included. METHODOLOGY Anthropometric, spirometry and respiratory muscle strength data were assessed. Maximum rate of pressure development (MRPD), maximum relaxation rate (MRR), time constant of decay curve (τ), contraction time (CT) and half-relaxation time (½ RT) were calculated from the nasal inspiratory pressure curve. RESULTS The sample was composed of 110 children (55 boys) with 1.045 as mean z-BMI-score. MRPD range of values was 8.09% to 10.86% rise/10 ms, MRR range of values was 8.09% to 10.86% fall/10 ms, τ range of values was 36.41 to 49.88 ms, CT range of values was 200 to 276 ms, ½ RT range of values was 117.5 to 148 ms and MRPD/MRR range of values was 0.71 to 1.04. The contractility and relaxation parameters did not present significant differences among children when compared by sex, age, nutritional status, or level of physical activity groups (P > .05). CONCLUSIONS The contractility and relaxation parameters present similar values among children and they are not influenced by age, sex, nutritional status or physical activity level.
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Affiliation(s)
- Maria Lira
- PneumoCardioVascular Lab/Hospital Universitário Onofre Lopes (HUOL), Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Laboratório de Inovação Tecnológica em Reabilitação, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Guilherme Fregonezi
- PneumoCardioVascular Lab/Hospital Universitário Onofre Lopes (HUOL), Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Laboratório de Inovação Tecnológica em Reabilitação, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Ana A Marcelino
- PneumoCardioVascular Lab/Hospital Universitário Onofre Lopes (HUOL), Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Laboratório de Inovação Tecnológica em Reabilitação, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Antonio Sarmento
- PneumoCardioVascular Lab/Hospital Universitário Onofre Lopes (HUOL), Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Laboratório de Inovação Tecnológica em Reabilitação, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
| | - Vanessa R Resqueti
- PneumoCardioVascular Lab/Hospital Universitário Onofre Lopes (HUOL), Empresa Brasileira de Serviços Hospitalares (EBSERH), Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil.,Laboratório de Inovação Tecnológica em Reabilitação, Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil
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Khurram OU, Fogarty MJ, Rana S, Vang P, Sieck GC, Mantilla CB. Diaphragm muscle function following midcervical contusion injury in rats. J Appl Physiol (1985) 2018; 126:221-230. [PMID: 30236045 DOI: 10.1152/japplphysiol.00481.2018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Midcervical spinal cord contusion injury results in tissue damage, disruption of spinal pathways, and motor neuron loss. Unilateral C4 contusion results in loss of 40%-50% of phrenic motor neurons ipsilateral to the injury (~25% of the total phrenic motor neuron pool). Over time after unilateral C4 contusion injury, diaphragm muscle (DIAm) electromyogram activity increases both contralateral and ipsilateral to the side of injury in rats, suggesting compensation because of increased activation of the surviving motor neurons. However, the impact of contusion injury on DIAm force generation is less clear. Transdiaphragmatic pressure (Pdi) was measured across motor behaviors over time after unilateral C4 contusion injury in adult male Sprague-Dawley rats. Maximum Pdi (Pdimax) was elicited by bilateral phrenic nerve stimulation at 7 days postinjury. We hypothesized that Pdimax is reduced following unilateral C4 contusion injury, whereas ventilatory behaviors of the DIAm are unimpaired. In support of our hypothesis, Pdimax was reduced by ~25% after unilateral C4 contusion, consistent with the extent of phrenic motor neuron loss following contusion injury. One day after contusion injury, the Pdi amplitude during airway occlusion was reduced from ~30 to ~20 cmH2O, but this reduction was completely reversed by 7 days postinjury. Ventilatory behaviors (~10 cmH2O), DIAm-specific force, and muscle fiber cross-sectional area did not differ between the laminectomy and contusion groups. These results indicate that the large reserve capacity for DIAm force generation allows for higher-force motor behaviors to be accomplished despite motor neuron loss, likely reflecting changes in motor unit recruitment. NEW & NOTEWORTHY Respiratory muscles such as the diaphragm generate the pressures necessary to accomplish a variety of motor behaviors ranging from ventilation to near-maximal expulsive behaviors. However, the impact of contusion injury on diaphragm pressure generation across behaviors is not clear. The present study shows that contusion injury impairs maximal pressure generation while preserving the ability of the diaphragm to accomplish lower-force motor behaviors, likely reflecting changes in diaphragm motor unit recruitment.
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Affiliation(s)
- Obaid U Khurram
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,School of Biomedical Sciences, The University of Queensland , St. Lucia, QLD , Australia
| | - Sabhya Rana
- Department of Neurobiology of Disease, Mayo Clinic , Rochester, Minnesota
| | - Pangdra Vang
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
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Kaminska M, Noel F, Petrof BJ. Optimal method for assessment of respiratory muscle strength in neuromuscular disorders using sniff nasal inspiratory pressure (SNIP). PLoS One 2017; 12:e0177723. [PMID: 28520769 PMCID: PMC5433762 DOI: 10.1371/journal.pone.0177723] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 05/02/2017] [Indexed: 11/30/2022] Open
Abstract
Background The ability to accurately determine respiratory muscle strength is vitally important in patients with neuromuscular disorders (NMD). Sniff nasal inspiratory pressure (SNIP), a test of inspiratory muscle strength, is easier to perform for many NMD patients than the more commonly used determination of maximum inspiratory pressure measured at the mouth (MIP). However, due to an inconsistent approach in the literature, the optimal technique to perform the SNIP maneuver is unclear. Therefore, we systematically evaluated the impact of performing the maneuver with nostril contralateral to the pressure-sensing probe open (SNIPOP) versus closed (SNIPCL), on determination of inspiratory muscle strength in NMD patients as well as control subjects with normal respiratory muscle function. Methods NMD patients (n = 52) and control subjects without respiratory dysfunction (n = 52) were studied. SNIPOP, SNIPCL, and MIP were measured during the same session and compared using ANOVA. Agreement and bias were assessed with intraclass correlation coefficients (ICC) and Bland-Altman plots. Results Mean MIP values were 58.2 and 94.0 cmH2O in NMD and control subjects, respectively (p<0.001). SNIPCL was greater than SNIPOP in NMD (51.9 ±31.0 vs. 36.9 ±25.4 cmH2O; p<0.001) as well as in controls (89.2 ±28.1 vs. 69.2 ±29.2 cmH2O; p<0.001). In both populations, the ICC between MIP and SNIPCL (NMD = 0.78, controls = 0.35) was higher than for MIP and SNIPOP (NMD = 0.53, controls = 0.06). In addition, SNIPCL was more often able to exclude inspiratory muscle weakness than SNIPOP. Conclusions SNIPCL values are systematically higher than SNIPOP in both normal subjects and NMD patients. Therefore, SNIPCL is a useful complementary test for ruling out inspiratory muscle weakness in individuals with low MIP values.
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Affiliation(s)
- Marta Kaminska
- Respiratory Division & Sleep Laboratory, McGill University Health Centre, Montreal, Quebec, Canada
- Respiratory Epidemiology and Clinical Research Unit, McGill University Health Centre, Montreal, Quebec, Canada
- Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- * E-mail:
| | - Francine Noel
- Respiratory Division & Sleep Laboratory, McGill University Health Centre, Montreal, Quebec, Canada
- Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Basil J. Petrof
- Respiratory Division & Sleep Laboratory, McGill University Health Centre, Montreal, Quebec, Canada
- Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Meakins Christie Laboratories, McGill University, Montreal, Quebec, Canada
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Laghi F, Langbein WE, Antonescu-Turcu A, Jubran A, Bammert C, Tobin MJ. Respiratory and Skeletal Muscles in Hypogonadal Men with Chronic Obstructive Pulmonary Disease. Am J Respir Crit Care Med 2005; 171:598-605. [PMID: 15591465 DOI: 10.1164/rccm.200412-1643oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Hypogonadism, found in about one-third of patients with chronic obstructive pulmonary disease (COPD), has potential for decreasing muscle mass and muscle performance. Compared with eugonadal patients, we hypothesized that hypogonadal patients with COPD have decreased respiratory and skeletal muscle performance. Nineteen hypogonadal and 20 eugonadal men with COPD (FEV(1) 1.14 +/- 0.08 and 1.17 +/- 0.11 L [standard error], respectively) were studied. Diaphragmatic contractility, assessed as transdiaphragmatic twitch pressure generated by phrenic nerve stimulation, was similar in hypogonadal and eugonadal patients: 20.6 +/- 2.2 and 19.8 +/- 2.5 cm H(2)O, respectively. During progressive inspiratory threshold loading, hypogonadal and eugonadal patients had similar respiratory muscle endurance times (302 +/- 29 and 313 +/- 48 seconds, respectively) and airway pressure sustained during the last minute of loading (38.2 +/- 3.0 and 40.5 +/- 4.7 cm H(2)O, respectively) (similar to predicted values in healthy subjects). Hypogonadal and eugonadal patients had equivalent limb muscle strength and endurance. During cycle exercise to exhaustion, exercise performance, gas exchange, and respiratory muscle recruitment (estimated by esophageal and gastric pressure swings during tidal breathing) were similar in both groups. In conclusion, hypogonadism does not decrease respiratory or limb muscle performance and exercise capacity in men with moderate-to-severe COPD who, for the most part, are not underweight.
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Affiliation(s)
- Franco Laghi
- Division of Pulmonary and Critical Care Medicine, Edward Hines Jr. VA Hospital, 111N 5th Avenue and Roosevelt Road, Hines, IL 60141, USA.
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Lewis MI, Fournier M, Da X, Li H, Mosenifar Z, McKenna RJ, Cohen AH. Short-term influences of lung volume reduction surgery on the diaphragm in emphysematous hamsters. Am J Respir Crit Care Med 2004; 170:753-9. [PMID: 15201133 DOI: 10.1164/rccm.200402-181oc] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
With emphysema, diaphragm length adaptation results in shortened fibers. We hypothesize that passive diaphragm stretch occurring acutely after lung volume reduction surgery (LVRS) results in fiber injury. Bilateral LVRS was performed in emphysematous hamsters. Studies were performed 1 (D1) and 4 (D4) days after LVRS, and compared with sham-treated groups. Sarcolemmal rupture was evident in 10.9% of fibers in LVRS-D1 and reduced to 1.6% in LVRS-D4. Ultrastructural analysis revealed focal abnormalities in both LVRS-D1 and LVRS-D4 animals in over one-third of fibers. Myofibrillar disruption was not observed in sham-treated animals. Diaphragm insulin-like growth factor-I (IGF-I) was increased in LVRS-D4 compared with other emphysematous groups. Increased IGF-I immunoreactivity was localized to types IIA and I fibers. The abundance of the splice variant of IGF-I mRNA sensitive to muscle stretch (IGF-IEb) increased 3.2-fold in LVRS D-4 diaphragms, compared with emphysema-sham animals. The main form of IGF-I mRNA was unchanged. Marked force deficit was observed in the LVRS-D1 diaphragm, compared with emphysema-sham and emphysema (no surgery) animals. These data highlight a markedly compromised ventilatory pump acutely after LVRS. Acute fiber stretch predisposes to muscle fiber injury and may also be a necessary mechanotransductive stimulus for fiber remodeling as the diaphragm adapts to reduced lung volume.
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Affiliation(s)
- Michael I Lewis
- Division of Pulmonary/Critical Care Medicine, Cedars-Sinai Medical Center, David Geffen School of Medicine at University of California, Los Angeles, CA 90048, USA.
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Laghi F, Cattapan SE, Jubran A, Parthasarathy S, Warshawsky P, Choi YSA, Tobin MJ. Is weaning failure caused by low-frequency fatigue of the diaphragm? Am J Respir Crit Care Med 2003; 167:120-7. [PMID: 12411288 DOI: 10.1164/rccm.200210-1246oc] [Citation(s) in RCA: 216] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Because patients who fail a trial of weaning from mechanical ventilation experience a marked increase in respiratory load, we hypothesized that these patients develop diaphragmatic fatigue. Accordingly, we measured twitch transdiaphragmatic pressure using phrenic nerve stimulation in 11 weaning failure and 8 weaning success patients. Measurements were made before and 30 minutes after spontaneous breathing trials that lasted up to 60 minutes. Twitch transdiaphragmatic pressure was 8.9 +/- 2.2 cm H2O before the trials and 9.4 +/- 2.4 cm H2O after their completion in the weaning failure patients (p = 0.17); the corresponding values in the weaning success patients were 10.3 +/- 1.5 and 11.2 +/- 1.8 cm H2O (p = 0.18). Despite greater load (p = 0.04) and diaphragmatic effort (p = 0.01), the weaning failure patients did not develop low-frequency fatigue probably because of greater recruitment of rib cage and expiratory muscles (p = 0.004) and because clinical signs of distress mandating the reinstitution of mechanical ventilation arose before the development of fatigue. Twitch pressure revealed considerable diaphragmatic weakness in many weaning failure patients. In conclusion, in contrast to our hypothesis, weaning failure was not accompanied by low-frequency fatigue of the diaphragm, although many weaning failure patients displayed diaphragmatic weakness.
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Affiliation(s)
- Franco Laghi
- Division of Pulmonary and Critical Care Medicine, Edward Hines Jr. Veterans Administration Hospital, Hines, Illinois 60141, USA.
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Bellemare F, Cordeau MP, Couture J, Lafontaine E, Leblanc P, Passerini L. Effects of emphysema and lung volume reduction surgery on transdiaphragmatic pressure and diaphragm length. Chest 2002; 121:1898-910. [PMID: 12065355 DOI: 10.1378/chest.121.6.1898] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVES To determine the effect of emphysema and lung volume reduction surgery (LVRS) on diaphragm length (Ldi) and its capacity to generate transdiaphragmatic pressure (Pdi). DESIGN Prospective clinical trial with a parallel group design. SETTING Laboratory investigations in normal volunteers recruited by advertisement and in emphysema outpatients being evaluated for elective LVRS. STUDY POPULATION Thirteen normal subjects and 13 emphysema patients matched for age and sex. Six emphysema patients underwent LVRS. MEASUREMENTS Ldi and maximal Pdi during static inspiratory efforts (PdiMax) were measured at three different lung volumes (LVs). Pdi during maximal bilateral phrenic nerve twitch stimulation (PdiTw) was measured at functional residual capacity (FRC). All measurements were repeated at 3, 6, and 12 months postoperatively. RESULTS Ldi, PdiMax, and PdiTw were lower in emphysema patients than in normal subjects at their respective LVs. PdiMax and PdiTw at FRC returned within the normal range after LVRS in emphysema patients. The relationships between PdiMax and LV or Ldi were shifted respectively to higher LV and shorter Ldi in emphysema patients relative to normal subjects, both before and after LVRS. LVRS effected craniad displacement of the diaphragm but no change in rib cage dimensions. Improvements in dyspnea and quality of life after LVRS correlated with changes in LV and Ldi but not with changes in airway caliber. CONCLUSION Adaptive mechanisms, consistent with sarcomere deletion, tend to restore diaphragm strength in emphysema patients at FRC, which are fully expressed after LVRS. Lung remodeling by LVRS may alter pleural surface pressure distribution, causing a sustained change in chest wall shape.
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Affiliation(s)
- François Bellemare
- Research Center, University of Montreal Health Center, Hôtel-Dieu, Montréal, PQ, Canada
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Polkey MI, Moxham J. Clinical aspects of respiratory muscle dysfunction in the critically ill. Chest 2001; 119:926-39. [PMID: 11243977 DOI: 10.1378/chest.119.3.926] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- M I Polkey
- Respiratory Muscle Laboratory, Royal Brompton Hospital, National Heart & Lung Institute, London, UK.
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McKenzie DK, Gorman RB, Tolman J, Pride NB, Gandevia SC. Estimation of diaphragm length in patients with severe chronic obstructive pulmonary disease. RESPIRATION PHYSIOLOGY 2000; 123:225-34. [PMID: 11007989 DOI: 10.1016/s0034-5687(00)00172-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In patients with advanced chronic obstructive pulmonary disease (COPD) diaphragm function may be compromised because of reduced muscle fibre length. Diaphragm length (L(Di)) can be estimated from measurements of transverse diameter of the rib cage (D(Rc)) and the length of the zone of apposition (L(Zapp)) in healthy subjects, but this method has not been validated in patients with COPD. Postero-anterior chest radiographs were obtained at total lung capacity (TLC), functional residual capacity (FRC) and residual volume (RV) in nine male patients with severe COPD (mean [S.D.]; FEV(1), 23 [6] %pred.; FRC, 199 [15] %pred.). Radiographs taken at TLC were used to identify the lateral costal insertions of the diaphragm (L(Zapp) assumed to approach zero at TLC). L(Di) was measured directly and also estimated from measurements of L(Zapp) and D(Rc) using a prediction equation derived from healthy subjects. The estimation of L(Di) was highly accurate with an intraclass correlation coefficient of 0.93 and 95% CI of approximately +/-8% of the true value. L(Di) decreased from 426 (64) mm at RV to 305 (31) mm at TLC. As there were only small and variable changes in D(Rc) across the lung volume range, most of the L(Di) changes occurred in the zone of apposition. Additional studies showed that measurements of L(Di) from PA and lateral radiographs performed at different lung volumes were tightly correlated. These results suggest that non-invasive measurements of L(Zapp) in the coronal plane (e.g. using ultrasonography) and D(Rc) (e.g. using magnetometers) can be used to provide an accurate estimate of L(Di) in COPD patients.
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Affiliation(s)
- D K McKenzie
- Department of Respiratory Medicine, Prince of Wales Hospital, Randwick, Sydney 2031, Australia.
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Abstract
Maximal static inspiratory pressure (P(IMAX)) generated at the mouth is one of the tests of inspiratory muscle strength in children. In adults, inspiratory muscle strength has also been assessed using sniff nasal inspiratory pressure (SNIP). This test is easier to perform than P(IMAX) and might therefore be applicable to children. To test this hypothesis, we measured P(IMAX) and SNIP in 116 children aged 4 to 11 years (54 girls, 62 boys). P(IMAX) was measured using a tube mouthpiece and SNIP using a tightly fitting plug in one nostril, while a sniff was performed through the other nostril. Both tests were performed from functional residual capacity (FRC). Pressure was measured with a differential pressure transducer and displayed in real time on a computer screen. Weight, standing height, sitting height, gender, and age were recorded. There was a significant difference (P < 0.01) in group mean (SD) data between SNIP (81.3 (27.4) cmH(2)O) and P(IMAX) (67.9 (28.1) cmH(2)O). Bland/Altman analysis demonstrated a mean difference of -13.5 cmH(2)O (SD 21.4) between the techniques. Regression analysis indicated highly significant relations (P < 0.01) between SNIP and P(IMAX), and between weight, standing and sitting height, and age for SNIP, and between weight, standing height, and age for P(IMAX). SNIP and P(IMAX) were greater in boys than girls (83.2 vs. 79.2 cmH(2)O SNIP; 72.9 vs. 62.0 cmH(2)O P(IMAX)), but this difference was only significant for P(IMAX) (P < 0.05). SNIP was significantly greater than P(IMAX) (P < 0.01) in both boys and girls. These data suggest that SNIP provides a simple, noninvasive additional test to P(IMAX) for assessing inspiratory muscle strength in children.
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Affiliation(s)
- G F Rafferty
- Department of Child Health, Guy's, King's, and St. Thomas' School of Medicine, King's College Hospital, London, UK
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Hodges PW, Butler JE, McKenzie DK, Gandevia SC. Contraction of the human diaphragm during rapid postural adjustments. J Physiol 1997; 505 ( Pt 2):539-48. [PMID: 9423192 PMCID: PMC1160083 DOI: 10.1111/j.1469-7793.1997.539bb.x] [Citation(s) in RCA: 191] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. The response of the diaphragm to the postural perturbation produced by rapid flexion of the shoulder to a visual stimulus was evaluated in standing subjects. Gastric, oesophageal and transdiaphragmatic pressures were measured together with intramuscular and oesophageal recordings of electromyographic activity (EMG) in the diaphragm. To assess the mechanics of contraction of the diaphragm, dynamic changes in the length of the diaphragm were measured with ultrasonography. 2. With rapid flexion of the shoulder in response to a visual stimulus, EMG activity in the costal and crural diaphragm occurred about 20 ms prior to the onset of deltoid EMG. This anticipatory contraction occurred irrespective of the phase of respiration in which arm movement began. The onset of diaphragm EMG coincided with that of transversus abdominis. 3. Gastric and transdiaphragmatic pressures increased in association with the rapid arm flexion by 13.8 +/- 1.9 (mean +/- S.E.M.) and 13.5 +/- 1.8 cmH2O, respectively. The increases occurred 49 +/- 4 ms after the onset of diaphragm EMG, but preceded the onset of movement of the limb by 63 +/- 7 ms. 4. Ultrasonographic measurements revealed that the costal diaphragm shortened and then lengthened progressively during the increase in transdiaphragmatic pressure. 5. This study provides definitive evidence that the human diaphragm is involved in the control of postural stability during sudden voluntary movement of the limbs.
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Affiliation(s)
- P W Hodges
- Prince of Wales Medical Research Institute, Sydney, Australia
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Kyroussis D, Mills GH, Polkey MI, Hamnegard CH, Koulouris N, Green M, Moxham J. Abdominal muscle fatigue after maximal ventilation in humans. J Appl Physiol (1985) 1996; 81:1477-83. [PMID: 8904556 DOI: 10.1152/jappl.1996.81.4.1477] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Abdominal muscles are the principal muscles of active expiration. To investigate the possibility of abdominal muscle low-frequency fatigue after maximal ventilation in humans, we stimulated the nerve roots supplying the abdominal muscles. We used a magnetic stimulator (Magstim 200) powering a 90-mm circular coil and studied six normal subjects. To assess the optimum level of stimulation and posture, we stimulated at each intervertebral level between T7 and L1 in the prone, supine, and seated positions. At T10, we used increasing power outputs to assess the pressure-power relationship. Care was taken to avoid muscle potentiation. Twitch gastric pressure (Pga) was recorded with a balloon-tipped catheter. Mean (+/-SD) baseline twitch Pga measured with the subjects in the prone position at T10 was 23.5 +/- 5.4 cmH2O. Within-occasion mean twitch Pga coefficient of variation was 4.6 +/- 1.1%. Twitch Pga was measured with the subjects in the prone position with stimulation over T10 before and after 2 min of maximal isocapnic ventilation (MIV). Twenty minutes after MIV, mean twitch Pga fell by 17 +/- 9.1% (P = 0.03) and remained low 90 min after MIV. We conclude that after maximal ventilation in humans there is a reduction of twitch Pga and, therefore, of low-frequency fatigue in abdominal muscles.
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Affiliation(s)
- D Kyroussis
- Kings College Hospital, London, United Kingdom
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Kyroussis D, Mills GH, Polkey MI, Hamnegard CH, Wragg S, Road J, Green M, Moxham J. Effect of maximum ventilation on abdominal muscle relaxation rate. Thorax 1996; 51:510-5. [PMID: 8711679 PMCID: PMC473596 DOI: 10.1136/thx.51.5.510] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND When the demand placed on the respiratory system is increased, the abdominal muscles become vigorously active to achieve expiration and facilitate subsequent inspiration. Abdominal muscle function could limit ventilatory capacity and a method to detect abdominal muscle fatigue would be of value. The maximum relaxation rate (MRR) of skeletal muscle has been used as an early index of the onset of the fatiguing process and precedes failure of force generation. The aim of this study was to measure MRR of abdominal muscles and to investigate whether it slows after maximum isocapnic ventilation (MIV). METHODS Five normal subjects were studied. Each performed short sharp expiratory efforts against a 3 mm orifice before and immediately after a two minute MIV. Gastric pressure (PGA) was recorded and MRR (% pressure fall/10 ms) for each PGA trace was determined. RESULTS Before MIV the mean (SD) maximum PGA MRR for the five subjects was 7.1 (0.8)% peak pressure fall/10 ms. Following MIV mean PGA MRR was decreased by 30% (range 25-35%), returning to control values within 5-10 minutes. CONCLUSIONS The MRR of the abdominal muscles, measured from PGA, is numerically similar to that described for the diaphragm and other skeletal muscles. After two minutes of maximal isocapnic ventilation abdominal muscle MRR slows, indicating that these muscles are sufficiently heavily loaded to initiate the fatiguing process.
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Affiliation(s)
- D Kyroussis
- Respiratory Muscle Laboratories, Royal Brompton and King's College Hospitals, London, UK
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Chan CC, Cheong TH, Wang YT, Poh SC. Transdiaphragmatic pressure in young adult Singaporean subjects--normal values and a comparison between different respiratory manoeuvres. AUSTRALIAN AND NEW ZEALAND JOURNAL OF MEDICINE 1996; 26:75-81. [PMID: 8775532 DOI: 10.1111/j.1445-5994.1996.tb02910.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Most published normal values for transdiaphragmatic pressure (Pdi) have been from Caucasian subjects and there is no universal agreement regarding the most appropriate manoeuvre for assessing Pdi. AIMS The aims of our study were to obtain normal values and to compare the different manoeuvres used to assess Pdi in normal young Singaporean adults. METHODS Twenty-four normal subjects (23 Chinese, one Indian) were studied by measuring Pdi during maximal sniffs from functional residual capacity (sniff Pdi), maximal inspiration to total lung capacity (Pdi TLC) and maximal static inspiratory efforts from residual volume (Pdi PImax). RESULTS Mean values +/- SD for sniff Pdi, Pdi TLC and Pdi PImax were 101.8 +/- 31.7, 46.8 +/- 26.4 and 83.5 +/- 35.5 cm H2O respectively. Sniff Pdi was significantly higher than Pdi TLC (p < 0.001) and Pdi PImax (p = 0.005). Pdi PImax was significantly higher than Pdi TLC (p < 0.001). Males had significantly higher values for sniff Pdi (p = 0.026) and Pdi PImax (p = 0.022) than females. There was a significant correlation between the different methods of recording Pdi. Sniff Pdi had the highest values, least between- and within-subject variation and most consistent pattern of respiratory muscle recruitment with the lowest proportion of negative gastric pressure (Pg) values (p < 0.001). CONCLUSIONS Therefore, sniff Pdi may be better than Pdi TLC and Pdi PImax in assessing diaphragm function. Also, our subjects seemed to have lower sniff Pdi and Pdi PImax, and higher Pdi TLC compared with Caucasian subjects.
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Affiliation(s)
- C C Chan
- Department of Respiratory Medicine, Tan Tock Seng Hospital, Singapore
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Abstract
BACKGROUND Inspiratory muscle strength is often better reflected by oesophageal pressure during a maximal sniff (sniff POES) than by maximal inspiratory pressure (PImax). Sniff POES can be estimated non-invasively by measuring the sniff nasal inspiratory pressure (SNIP). The aim was to establish maximal normal values for the SNIP and to compare them with PImax. METHODS One hundred and sixty healthy subjects (80 men) aged 20-80 years were recruited. All subjects had a forced vital capacity (FVC) of > 80%, a forced expiratory volume in one second (FEV1)/FVC of > 85% predicted value, and a body mass index of 18-31 kg/m2. Because PImax is known to be reduced in the supine posture, the SNIP was measured in both the sitting and the supine positions. PImax sustained over one second was measured from functional residual capacity (FRC) in the sitting position with a standard flanged mouthpiece during four manoeuvres. SNIP was measured from FRC in the sitting and supine positions using a catheter through a plug occluding one nostril during 10 maximal sniffs through the contralateral nostril. For each test the largest pressure measured in cm H2O was taken into account. RESULTS For both men and women maximal SNIP was negatively correlated with age, and was similar in the sitting and the supine positions. In the sitting position maximal SNIP was greater or equal to PImax in 107 of 160 subjects. The mean (SD) ratio SNIP/PImax was 1.08 (0.22) in men and 1.17 (0.29) in women. CONCLUSIONS Normal values of maximal SNIP can be predicted from age and sex. Maximal SNIP is similar in the sitting and the supine position and is significantly higher than PImax in healthy subjects. The low level of agreement between maximal SNIP and PImax indicates that the two manoeuvres are not interchangeable but complementary.
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Affiliation(s)
- C Uldry
- Division de Pneumologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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McKenzie DK, Bellemare F. Respiratory muscle fatigue. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 384:401-14. [PMID: 8585468 DOI: 10.1007/978-1-4899-1016-5_32] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ventilatory failure may accompany a variety of pulmonary and neuromuscular diseases. There has been much controversy about whether this failure is due to respiratory muscle fatigue at peripheral sites or a failure of drive at sites within the central nervous system. The chapter reviews this topic.
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Affiliation(s)
- D K McKenzie
- Department of Respiratory Medicine, University of New South Wales, Sydney, Australia
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McKenzie DK, Gandevia SC, Gorman RB, Southon FC. Dynamic changes in the zone of apposition and diaphragm length during maximal respiratory efforts. Thorax 1994; 49:634-8. [PMID: 8066555 PMCID: PMC475047 DOI: 10.1136/thx.49.7.634] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Clinical tests of diaphragmatic strength are limited by the wide normal variation in maximal pressure which result, in part, from changes in diaphragmatic length. During relaxation at different lung volumes diaphragmatic length (LDI) can be estimated from the length of the zone of apposition (LZapp) and the transverse diameter of the rib cage (DRC). A study was carried out in two subjects using sequential digital radiography at six frames/second to determine whether these relations apply during maximal respiratory efforts which distort the rib cage and diaphragm. METHODS The length of the anteroposterior contour of the diaphragm and DRC were determined by curve fitting. LZapp was measured with a millimetre rule. RESULTS A significant correlation was found between LDI and LZapp during both maximal inspiratory and expulsive manoeuvres (R2 = 0.88 and 0.52). LDI was estimated from the measurements of LZapp and DRC using a multiple regression equation derived from measurements during static relaxation. Despite the complex dynamic events at the onset of these "static" manoeuvres, actual LDI correlated strongly with derived LDI using all data for the two manoeuvres in each subject (R2 = 0.95 and 0.84). Measurements with ultrasonography (12 cm linear probe) and magnetometers confirmed the changes in LZapp and DRC during inspiratory and expulsive efforts. CONCLUSIONS Non-invasive measurements of LZapp and DRC can be used to derive an accurate estimate of diaphragmatic length under dynamic conditions.
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Affiliation(s)
- D K McKenzie
- Department of Respiratory Medicine, Prince Henry Hospital, University of New South Wales, Sydney, Australia
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