Noninvasive determination of upper airway resistance and flow limitation

2004 ◽  
Vol 97 (5) ◽  
pp. 1840-1848 ◽  
Author(s):  
Khaled F. Mansour ◽  
James A. Rowley ◽  
M. Safwan Badr
Keyword(s):  
Airway Resistance ◽  
Accurate Determination ◽  
Upper Airway ◽  
High Sensitivity ◽  
Polynomial Equation ◽  
Flow Limitation ◽  
Flow Loop ◽  
Pressure Flow ◽  
Upper Airway Resistance

We have shown that a polynomial equation, F(P) = AP3 + BP2 + CP + D, where F is flow and P is pressure, can accurately determine the presence of inspiratory flow limitation (IFL). This equation requires the invasive measurement of supraglottic pressure. We hypothesized that a modification of the equation that substitutes time for pressure would be accurate for the detection of IFL and allow for the noninvasive measurement of upper airway resistance. The modified equation is F( t) = At3 + Bt2 + Ct + D, where F is flow and t is time from the onset of inspiration. To test our hypotheses, data analysis was performed as follows on 440 randomly chosen breaths from 18 subjects. First, we performed linear regression and determined that there is a linear relationship between pressure and time in the upper airway ( R2 0.96 ± 0.05, slope 0.96 ± 0.06), indicating that time can be a surrogate for pressure. Second, we performed curve fitting and found that polynomial equation accurately predicts the relationship between flow and time in the upper airway ( R2 0.93 ± 0.12, error fit 0.02 ± 0.08). Third, we performed a sensitivity-specificity analysis comparing the mathematical determination of IFL to manual determination using a pressure-flow loop. Mathematical determination had both high sensitivity (96%) and specificity (99%). Fourth, we calculated the upper airway resistance using the polynomial equation and compared the measurement to the manually determined upper airway resistance (also from a pressure-flow loop) using Bland-Altman analysis. Mean difference between calculated and measured upper airway resistance was 0.0 cmH2O·l−1·s−1 (95% confidence interval −0.2, 0.2) with upper and lower limits of agreement of 2.8 cmH2O·l−1·s−1 and −2.8 cmH2O·l−1·s−1. We conclude that a polynomial equation can be used to model the flow-time relationship, allowing for the objective and accurate determination of upper airway resistance and the presence of IFL.

Mathematical Determination of Inspiratory Upper Airway Resistance Using a Polynomial Equation

2003 ◽  
Vol 7 (4) ◽  
pp. 151-158 ◽  
Author(s):  
Khaled Mansour ◽  
M. Safwan Badr ◽  
Mahdi A. Shkoukani ◽  
James A. Rowley
Keyword(s):  
Airway Resistance ◽  
Upper Airway ◽  
Polynomial Equation ◽  
Upper Airway Resistance

A mathematical model to detect inspiratory flow limitation during sleep

2002 ◽  
Vol 93 (3) ◽  
pp. 1084-1092 ◽  
Author(s):  
Khaled F. Mansour ◽  
James A. Rowley ◽  
A. A. Meshenish ◽  
Mahdi A. Shkoukani ◽  
M. Safwan Badr
Keyword(s):  
Mathematical Model ◽  
Polynomial Function ◽  
Upper Airway ◽  
Correlation Coefficients ◽  
High Sensitivity ◽  
Inspiratory Flow ◽  
Flow Limitation ◽  
Pressure Flow ◽  
Objective Detection

The physiological significance of inspiratory flow limitation (IFL) has recently been recognized, but methods of detecting IFL can be subjective. We sought to develop a mathematical model of the upper airway pressure-flow relationship that would objectively detect flow limitation. We present a theoretical discussion that predicts that a polynomial function [F(P) = AP3 + BP2 + CP + D, where F(P) is flow and P is supraglottic pressure] best characterizes the pressure-flow relationship and allows for the objective detection of IFL. In protocol 1, step 1, we performed curve-fitting of the pressure-flow relationship of 20 breaths to 5 mathematical functions and found that highest correlation coefficients ( R 2) for quadratic (0.88 ± 0.10) and polynomial (0.91 ± 0.05; P < 0.05 for both compared with the other functions) functions. In step 2, we performed error-fit calculations on 50 breaths by comparing the quadratic and polynomial functions and found that the error fit was lowest for the polynomial function (3.3 ± 0.06 vs. 21.1 ± 19.0%; P < 0.001). In protocol 2, we performed sensitivity/specificity analysis on two sets of breaths (50 and 544 breaths) by comparing the mathematical determination of IFL to manual determination. Mathematical determination of IFL had high sensitivity and specificity and a positive predictive value (>99% for each). We conclude that a polynomial function can be used to predict the relationship between pressure and flow in the upper airway and objectively determine the presence of IFL.

The evaluation of physiologic decannulation readiness according to upper airway resistance measurement

2008 ◽  
Vol 139 (4) ◽  
pp. 535-540 ◽  
Author(s):  
Chunli Gao ◽  
Liang Zhou ◽  
Chunsheng Wei ◽  
Matthew R. Hoffman ◽  
Cai Li ◽  
...  
Keyword(s):  
Airway Resistance ◽  
Operating Characteristic ◽  
Upper Airway ◽  
High Sensitivity ◽  
Deep Breathing ◽  
Clinical Criteria ◽  
Receiver Operating Characteristic Curves ◽  
Upper Airway Resistance ◽  
Laryngeal Disease ◽  
Subglottal Pressure

Objective To measure the upper-airway resistance in patients with tracheostomies and determine the value representing decannulation readiness. Subjects and Methods Fifty-six patients with tracheostomies resultant to laryngeal disease participated in this study. Forty patients met clinical criteria for decannulation; 16 did not. Subglottal pressure was measured with a tube connected to the tracheostomy tube, and airflow was monitored simultaneously using a facemask. Upper-airway resistance measurements were recorded during shallow and deep breathing. Results During both shallow and deep breathing, the inspiratory and expiratory resistances were significantly higher for the group unsuitable for decannulation ( P < .0001). The areas under the receiver operating characteristic curves were 0.938 or greater for the four curves, indicating a high sensitivity and specificity of resistance measures for diagnosis. Conclusions Objective measurement of upper-airway resistance during shallow and deep breathing may be a useful parameter in determining decannulation readiness of tracheostomized patients.

391 Upper Airway Resistance Syndrome is associated with high Cyclic Alternating Pattern

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A155-A156
Author(s):  
Luciana Godoy ◽  
Letícia Soster ◽  
Clarissa Bueno ◽  
Sonia Togeiro ◽  
Dalva Poyares ◽  
...  
Keyword(s):  
Airway Resistance ◽  
Upper Airway ◽  
Sleep Fragmentation ◽  
Control Group ◽  
Flow Limitation ◽  
Upper Airway Resistance Syndrome ◽  
Arousal Index ◽  
Upper Airway Resistance ◽  
Cyclic Alternating Pattern ◽  
Cap Rate

Abstract Introduction Upper Airway Resistance Syndrome (UARS) is suspected in individuals with excessive daytime sleepiness, fatigue, and sleep fragmentation associated with increased respiratory effort. UARS can negatively impact daytime function. Conventional polysomnography parameters do not demonstrate significant abnormalities in UARS patients but increase in RERAs and arousal index. Cyclic alternating pattern (CAP) is a periodic electroencephalogram activity of non-REM sleep that expresses a condition of sleep instability. The objective of the study was to compare CAP components between UARS patients and health individuals. Methods Fifteen subjects with UARS and 15 age- and sex- matched controls had their sleep study blinded analyzed. UARS criteria were the presence of sleepiness (Epworth Sleepiness Scale – ESS - ≥ 10) and/or fatigue (Modified Fatigue Impact Scale ≥ 38) associated with an apnea/hypopnea index (AHI) ≤ 5 and a respiratory disturbance index (RDI) &gt; 5 events/hour of sleep, and/or flow limitation in more than 30% of total sleep time. Control group criteria were AHI &lt; 5 events/hour, RDI ≤ 5 events/hour and &lt; 30% of TST with flow limitation and ESS &lt; 10, without sleep, clinical, neurological, or psychiatric disorder. CAP electroencephalogram of both groups was analyzed. Results We found higher CAP rate (p = 0.05) and CAP index in N1 stage (p &lt; 0.001) and in N3 stage (p &lt; 0.001) in UARS patients compared to control group. Considering only CAP phase A1 analysis, UARS patients presented higher CAP rate (p = 0.05) and CAP index in N1 stage (p &lt; 0.001) as well as CAP index in N3 stage (p &lt; 0.001) compared to control group. Considering only CAP phase A2 analysis, UARS patients also presented higher number of CAP in N1 stage (p = 0.05). There was no significant difference for CAP phase A3 between groups. Conclusion Although UARS is associated with high arousal index, we found increase in CAP phase A1 and A2, which do not include necessarily AASM arousals, suggesting not only sleep fragmentation but also sleep instability. Support (if any) Associação Fundo de Incentivo à Pesquisa (AFIP) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP).

Motor responses to positive-pressure breathing in the developing opossum

1985 ◽  
Vol 58 (5) ◽  
pp. 1489-1495 ◽  
Author(s):  
J. P. Farber
Keyword(s):  
Airway Resistance ◽  
Upper Airway ◽  
Abdominal Muscle ◽  
Positive Pressure ◽  
Postnatal Life ◽  
Abdominal Muscles ◽  
Upper Airways ◽  
Motor Responses ◽  
Upper Airway Resistance ◽  
Upper Airway Muscles

The suckling opossum exhibits an expiration-phased discharge in abdominal muscles during positive-pressure breathing (PPB); the response becomes apparent, however, only after the 3rd-5th wk of postnatal life. The purpose of this study was to determine whether the early lack of activation represented a deficiency of segmental outflow to abdominal muscles or whether comparable effects were observed in cranial outflows to muscles of the upper airways due to immaturity of afferent and/or supraspinal pathways. Anesthetized suckling opossums between 15 and 50 days of age were exposed to PPB; electromyogram (EMG) responses in diaphragm and abdominal muscles were measured, along with EMG of larynx dilator muscles and/or upper airway resistance. In animals older than approximately 30 days of age, the onset of PPB was associated with a prolonged expiration-phased EMG activation of larynx dilator muscles and/or decreased upper airway resistance, along with expiratory recruitment of the abdominal muscle EMG. These effects persisted as long as the load was maintained. Younger animals showed only those responses related to the upper airway; in fact, activation of upper airway muscles during PPB could be associated with suppression of the abdominal motor outflow. After unilateral vagotomy, abdominal and upper airway motor responses to PPB were reduced. The balance between PPB-induced excitatory and inhibitory or disfacilitory influences from the supraspinal level on abdominal motoneurons and/or spinal processing of information from higher centers may shift toward net excitation as the opossum matures.

Sign in / Sign up

Export Citation Format

Share Document