Crying Vital Capacity and Maximal Inspiratory Pressure as Clinical Indicators of Readiness for Weaning of Infants Less Than a Year of Age

Objectives: The purpose of this study was to prospectively evaluate sleep patterns and the presence of sleep-disordered breathing in children with myasthenia gravis. We further aimed to examine the relationship between sleep and daytime respiratory function using spirometry tests including upright and supine forced vital capacity, sniff nasal inspiratory pressure, and maximal inspiratory pressure. Methods: Eleven children between 3 and 18 years old with confirmed myasthenia gravis were recruited from The Hospital for Sick Children Neuromuscular Clinic in this prospective observational study. After informed consent was obtained, patients underwent a comprehensive clinical assessment with collection of anthropometric data. Following this, all subjects performed pulmonary function tests, overnight polysomnography and completed the Epworth Sleepiness Scale questionnaire. Results: Two of eleven children who reported no symptoms of sleep disordered breathing were diagnosed with mild to moderate obstructive sleep apnea. Pulmonary function tests showed abnormal maximal inspiratory pressure in 6 of 11 patients, whereas seated forced vital capacity as well as seated to supine forced vital capacity ratios were normal in the entire group. Conclusions: In our small group of pediatric myasthenia gravis subjects, there was an unexpected finding of obstructive sleep apnea in 2 of the 11 patients studied. Maximal inspiratory pressure appears to be a more sensitive method of detecting abnormalities compared to upright or seated forced vital capacity. A larger multicenter study is needed to validate our findings and to determine the impact of obstructive sleep apnea in the pediatric myasthenia gravis population as well as risk factors associated with sleep disordered breathing.

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Lung volume specificity of inspiratory muscle training

Journal of Applied Physiology ◽

10.1152/jappl.1994.77.2.789 ◽

1994 ◽

Vol 77 (2) ◽

pp. 789-794 ◽

Cited By ~ 17

Author(s):

G. E. Tzelepis ◽

D. L. Vega ◽

M. E. Cohen ◽

F. D. McCool

Keyword(s):

Lung Volume ◽

Vital Capacity ◽

Inspiratory Muscle ◽

Control Group ◽

Residual Volume ◽

Maximal Inspiratory Pressure ◽

Muscle Training ◽

Inspiratory Capacity ◽

Lung Volumes ◽

Before And After

We examined the extent to which training-related increases of inspiratory muscle (IM) strength are limited to the lung volume (VL) at which the training occurs. IM strength training consisted of performing repeated static maximum inspiratory maneuvers. Three groups of normal volunteers performed these maneuvers at one of three lung volumes: residual volume (RV), relaxation volume (Vrel), or Vrel plus one-half of inspiratory capacity (Vrel + 1/2IC). A control group did not train. We constructed maximal inspiratory pressure-VL curves before and after a 6-wk training period. For each group, we found that the greatest improvements in strength occurred at the volume at which the subjects trained and were significantly greater for those who trained at low (36% for RV and 26% for Vrel) than at high volumes (13% for Vrel + 1/2IC). Smaller increments in strength were noted at volumes adjacent to the training volume. The range of vital capacity (VC) over which strength was increased was greater for those who trained at low (70% of VC) than at high VL (20% of VC). We conclude that the greatest improvements in IM strength are specific to the VL at which training occurs. However, the increase in strength, as well as the range of volume over which strength is increased, is greater for those who trained at the lower VL.

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Maximal Inspiratory Pressure in Respiratory Failure

CHEST Journal ◽

10.1378/chest.97.3_supplement.97s ◽

1990 ◽

Vol 97 (3) ◽

pp. 97S ◽

Cited By ~ 1

Author(s):

T.K. Aldrich ◽

D.J. Prezant ◽

J.P. Karpel ◽

A.S. Multz ◽

J.M. Hendlen

Keyword(s):

Respiratory Failure ◽

Inspiratory Pressure ◽

Maximal Inspiratory Pressure

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Inspiratory muscle strength in subjects with tetraplegia: viability of evaluation through the measurement of maximal inspiratory pressure

Fisioterapia em Movimento ◽

10.1590/0103-5150.027.003.ao07 ◽

2014 ◽

Vol 27 (3) ◽

pp. 371-377

Author(s):

Marlene Aparecida Moreno ◽

Juliana Viana Paris ◽

Raphael do Nascimento Pereira ◽

Antonio Roberto Zamunér ◽

Tais Mendes de Camargo ◽

...

Keyword(s):

Muscle Strength ◽

Cross Sectional Study ◽

Inspiratory Muscle ◽

Inspiratory Pressure ◽

Maximal Inspiratory Pressure ◽

Cross Sectional ◽

Pressure Meter ◽

Predicted Values ◽

Inspiratory Muscle Strength ◽

Sniff Nasal Inspiratory Pressure

Objective To analyze the values of maximal inspiratory pressure (MIP) and sniff nasal inspiratory pressure (SNIP) and to verify the existence of concordance between the two evaluation methodologies, in subjects with tetraplegia. Materials and methods Cross-sectional study with 17 tetraplegic men, aged 30.42 ± 7.67 years, who underwent MIP and SNIP evaluation using a respiratory pressure meter. Results The MIP and SNIP values obtained showed no difference when compared to each other (88.42 ± 29.39 vs. 86.68 ± 25.40 cmH2O, respectively). They were, however, significantly lower compared to the predicted values (MIP = 128.92 ± 7.18; SNIP = 114.11 ± 3.19 cmH2O), with the MIP values presenting correlation (r2 = 0.94; p < 0.0001) and concordance with those of the SNIP. Conclusions Both the MIP and SNIP values obtained were lower than the predicted values, indicating a reduction in inspiratory muscle strength (IMS). Both techniques showed correlation and concordance, suggesting that MIP can be used as a noninvasive method for IMS evaluation in this population.

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P168 Agreement between sniff nasal inspiratory pressure and mouth maximal inspiratory pressure in patients surviving severe acute hypercapnic respiratory failure in the ICU

CHEST Journal ◽

10.1016/j.chest.2017.04.070 ◽

2017 ◽

Vol 151 (5) ◽

pp. A66

Author(s):

N. Glatz ◽

G. Krull ◽

P.M. Soccal ◽

J.-P. Janssens ◽

D. Adler

Keyword(s):

Respiratory Failure ◽

Inspiratory Pressure ◽

Maximal Inspiratory Pressure ◽

Hypercapnic Respiratory Failure ◽

Acute Hypercapnic Respiratory Failure ◽

Sniff Nasal Inspiratory Pressure

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Maximal inspiratory pressure: does reproducibility indicate full effort?

Thorax ◽

10.1136/thx.50.1.40 ◽

1995 ◽

Vol 50 (1) ◽

pp. 40-43 ◽

Cited By ~ 58

Author(s):

T K Aldrich ◽

P Spiro

Keyword(s):

Inspiratory Pressure ◽

Maximal Inspiratory Pressure

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Noninvasive measurement of the tension-time index in children with neuromuscular disease

Journal of Applied Physiology ◽

10.1152/japplphysiol.01087.2002 ◽

2003 ◽

Vol 95 (3) ◽

pp. 931-937 ◽

Cited By ~ 34

Author(s):

Laura T. Mulreany ◽

Daniel J. Weiner ◽

Joseph M. McDonough ◽

Howard B. Panitch ◽

Julian L. Allen

Keyword(s):

Respiratory Failure ◽

Muscle Fatigue ◽

Neuromuscular Disease ◽

Respiratory Muscle ◽

Forced Expiratory Volume ◽

Inspiratory Pressure ◽

Maximal Inspiratory Pressure ◽

Respiratory Muscle Fatigue ◽

Time Index ◽

Tension Time

Respiratory muscle weakness is common in children with neuromuscular disease (NMD). We hypothesized that weakness puts them at risk for respiratory muscle fatigue, a harbinger of chronic respiratory failure. We therefore measured a noninvasive index of respiratory muscle fatigue, the tension-time index of the respiratory muscles (TTmus), in 11 children with NMD and 13 control subjects. Spirometric flow rates and maximal inspiratory pressure were significantly lower in the NMD group than in controls (43 ± 23 vs. 99 ± 21 cmH2O, P < 0.001). The mean TTmus was significantly higher in the NMD group than in controls (0.205 ± 0.117 vs. 0.054 ± 0.021, P < 0.001). The increase in TTmus was primarily due to an increase in the ratio of average mean inspiratory pressure to maximal inspiratory pressure, indicating decreased respiratory muscle strength reserve. We found a significant correlation between TTmus and the residual volume-to-total lung capacity ratio ( r = 0.504, P = 0.03) and a negative correlation between TTmus and forced expiratory volume in 1 s ( r = -0.704, P < 0.001). In conclusion, children with NMD are prone to respiratory muscle fatigue. TTmus may be useful in assessing tolerance during weaning from mechanical ventilation, identifying impending respiratory failure, and aiding in the decision to institute therapies.

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