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Effects of diaphragmatic control on the assessment of sniff nasal inspiratory pressure and maximum relaxation rate.

Benício K, Dias FA, Gualdi LP, Aliverti A, Resqueti VR, Fregonezi GA - Braz J Phys Ther (2015)

Bottom Line: SNIP values were significantly different in maneuvers with and without diaphC [without diaphC: -100 (SD=27.1) cmH2O/ with diaphC: -72.8 (SD=22.3) cmH2O; p<0.0001], normalized MRR values were not statistically different [without diaphC: -9.7 (SD=2.6); with diaphC: -8.9 (SD=1.5); p=0.19].Without diaphC, 40% of the sample did not reach the appropriate sniff criteria found in the literature.However, there was no influence on normalized MRR.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.

ABSTRACT

Objective: To assess the influence of diaphragmatic activation control (diaphC) on Sniff Nasal-Inspiratory Pressure (SNIP) and Maximum Relaxation Rate of inspiratory muscles (MRR) in healthy subjects.

Method: Twenty subjects (9 male; age: 23 (SD=2.9) years; BMI: 23.8 (SD=3) kg/m²; FEV1/FVC: 0.9 (SD=0.1)] performed 5 sniff maneuvers in two different moments: with or without instruction on diaphC. Before the first maneuver, a brief explanation was given to the subjects on how to perform the sniff test. For sniff test with diaphC, subjects were instructed to perform intense diaphragm activation. The best SNIP and MRR values were used for analysis. MRR was calculated as the ratio of first derivative of pressure over time (dP/dtmax) and were normalized by dividing it by peak pressure (SNIP) from the same maneuver.

Results: SNIP values were significantly different in maneuvers with and without diaphC [without diaphC: -100 (SD=27.1) cmH2O/ with diaphC: -72.8 (SD=22.3) cmH2O; p<0.0001], normalized MRR values were not statistically different [without diaphC: -9.7 (SD=2.6); with diaphC: -8.9 (SD=1.5); p=0.19]. Without diaphC, 40% of the sample did not reach the appropriate sniff criteria found in the literature.

Conclusion: Diaphragmatic control performed during SNIP test influences obtained inspiratory pressure, being lower when diaphC is performed. However, there was no influence on normalized MRR.

No MeSH data available.


Study design.
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f01: Study design.

Mentions: This is a cross-sectional, quasi-experimental study. Subjects were submitted tooutpatient assessment at the PneumoCardioVascular Performance Laboratory and thePneumoCardioVascular Lab/HUOL/EBSERH, UFRN. After selection, individuals wereassessed on the same day for collection of anthropometric and spirometric data todetermine their eligibility. SNIP tests were conducted after a 20-minute rest, with aminimum 60-minute interval between the two assessments, followed by MIP measurement.SNIP assessment was conducted twice. On both occasions, the examiner carefullydemonstrated the maneuver and then asked the subject to repeat it for familiarizationpurposes18,19. In assessment A, subjects received onlythe basic instructions recommended by the American Thoracic Society/EuropeanRespiratory Society (ATS/ERS)16, whichsuggests that the sniff maneuver requires little explanation and practice. Subjectsexecuted 5 sniff maneuvers without activating the diaphragm muscle. They wereinstructed to sniff with maximum effort, followed by a slow, sustained expirationwithout holding their breath. In assessment B, individuals were trained to breathe ina slow diaphragmatic breathing pattern. They were asked to breathe deeply throughtheir nose, while simultaneously moving the abdominal wall outwards. A period of 5 to10 minutes was established for training to ensure patients could correctly executethe maneuver. Success was evaluated visually, with maneuvers considered satisfactorywhen the abdomen clearly expanded on inspiration20. After being trained in diaphragmatic breathing, subjects were asked toperform ballistic stomach movements to familiarize themselves with the speed requiredduring the sniff. Next, participants were instructed to perform five consecutivesniffs concomitant to abdominal motion (DiaphCtrl) following the same instructionsapplied in assessment A (rapid maximum effort, followed by slow and sustainedexpiration), but emphasizing diaphragm control during execution. In both assessments,the subjects were prompted by being asked to take a "hard sniff". MIP was measured atthe end of the test after a 30-minute rest to prevent the static effort required frominterfering in obtaining SNIP values. The sequence of measurements was not randomizedbecause, once a maneuver has been taught, it is impossible to ask individuals toexecute it without applying the pattern learned and be certain they are performing itas they would have done before training, which could hamper result interpretation.The flow chart is shown in Figure 1.


Effects of diaphragmatic control on the assessment of sniff nasal inspiratory pressure and maximum relaxation rate.

Benício K, Dias FA, Gualdi LP, Aliverti A, Resqueti VR, Fregonezi GA - Braz J Phys Ther (2015)

Study design.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835170&req=5

f01: Study design.
Mentions: This is a cross-sectional, quasi-experimental study. Subjects were submitted tooutpatient assessment at the PneumoCardioVascular Performance Laboratory and thePneumoCardioVascular Lab/HUOL/EBSERH, UFRN. After selection, individuals wereassessed on the same day for collection of anthropometric and spirometric data todetermine their eligibility. SNIP tests were conducted after a 20-minute rest, with aminimum 60-minute interval between the two assessments, followed by MIP measurement.SNIP assessment was conducted twice. On both occasions, the examiner carefullydemonstrated the maneuver and then asked the subject to repeat it for familiarizationpurposes18,19. In assessment A, subjects received onlythe basic instructions recommended by the American Thoracic Society/EuropeanRespiratory Society (ATS/ERS)16, whichsuggests that the sniff maneuver requires little explanation and practice. Subjectsexecuted 5 sniff maneuvers without activating the diaphragm muscle. They wereinstructed to sniff with maximum effort, followed by a slow, sustained expirationwithout holding their breath. In assessment B, individuals were trained to breathe ina slow diaphragmatic breathing pattern. They were asked to breathe deeply throughtheir nose, while simultaneously moving the abdominal wall outwards. A period of 5 to10 minutes was established for training to ensure patients could correctly executethe maneuver. Success was evaluated visually, with maneuvers considered satisfactorywhen the abdomen clearly expanded on inspiration20. After being trained in diaphragmatic breathing, subjects were asked toperform ballistic stomach movements to familiarize themselves with the speed requiredduring the sniff. Next, participants were instructed to perform five consecutivesniffs concomitant to abdominal motion (DiaphCtrl) following the same instructionsapplied in assessment A (rapid maximum effort, followed by slow and sustainedexpiration), but emphasizing diaphragm control during execution. In both assessments,the subjects were prompted by being asked to take a "hard sniff". MIP was measured atthe end of the test after a 30-minute rest to prevent the static effort required frominterfering in obtaining SNIP values. The sequence of measurements was not randomizedbecause, once a maneuver has been taught, it is impossible to ask individuals toexecute it without applying the pattern learned and be certain they are performing itas they would have done before training, which could hamper result interpretation.The flow chart is shown in Figure 1.

Bottom Line: SNIP values were significantly different in maneuvers with and without diaphC [without diaphC: -100 (SD=27.1) cmH2O/ with diaphC: -72.8 (SD=22.3) cmH2O; p<0.0001], normalized MRR values were not statistically different [without diaphC: -9.7 (SD=2.6); with diaphC: -8.9 (SD=1.5); p=0.19].Without diaphC, 40% of the sample did not reach the appropriate sniff criteria found in the literature.However, there was no influence on normalized MRR.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.

ABSTRACT

Objective: To assess the influence of diaphragmatic activation control (diaphC) on Sniff Nasal-Inspiratory Pressure (SNIP) and Maximum Relaxation Rate of inspiratory muscles (MRR) in healthy subjects.

Method: Twenty subjects (9 male; age: 23 (SD=2.9) years; BMI: 23.8 (SD=3) kg/m²; FEV1/FVC: 0.9 (SD=0.1)] performed 5 sniff maneuvers in two different moments: with or without instruction on diaphC. Before the first maneuver, a brief explanation was given to the subjects on how to perform the sniff test. For sniff test with diaphC, subjects were instructed to perform intense diaphragm activation. The best SNIP and MRR values were used for analysis. MRR was calculated as the ratio of first derivative of pressure over time (dP/dtmax) and were normalized by dividing it by peak pressure (SNIP) from the same maneuver.

Results: SNIP values were significantly different in maneuvers with and without diaphC [without diaphC: -100 (SD=27.1) cmH2O/ with diaphC: -72.8 (SD=22.3) cmH2O; p<0.0001], normalized MRR values were not statistically different [without diaphC: -9.7 (SD=2.6); with diaphC: -8.9 (SD=1.5); p=0.19]. Without diaphC, 40% of the sample did not reach the appropriate sniff criteria found in the literature.

Conclusion: Diaphragmatic control performed during SNIP test influences obtained inspiratory pressure, being lower when diaphC is performed. However, there was no influence on normalized MRR.

No MeSH data available.