scholarly journals Hemodynamic effects of the inspiratory flow rate in patients with septic shock

Critical Care ◽  
10.1186/cc829 ◽  
2000 ◽  
Vol 4 (Suppl 1) ◽  
pp. P109
Author(s):  
A Koroneos ◽  
J Kalomenidis ◽  
F Moraitou ◽  
P Polakis ◽  
G Leptidis ◽  
...  
Keyword(s):  
Septic Shock ◽  
Flow Rate ◽  
Inspiratory Flow ◽  
Hemodynamic Effects ◽  
Inspiratory Flow Rate

Relationship of inspiratory flow rate and volume on digit tip skin and ulnar artery vasoconstrictor responses in healthy adults

2005 ◽  
Vol 69 (1-2) ◽  
pp. 95-100 ◽  
Author(s):  
Einar Wilder-Smith ◽  
Linda Liu ◽  
Khin Thein Ma Ma ◽  
Benjamin K.C. Ong
Keyword(s):  
Flow Rate ◽  
Ulnar Artery ◽  
Inspiratory Flow ◽  
Healthy Adults ◽  
Inspiratory Flow Rate ◽  
Relationship Of

scholarly journals Efficacy of Pressure Support in Compensating for Apparatus Work

1993 ◽  
Vol 21 (1) ◽  
pp. 67-71 ◽  
Author(s):  
A. D. Bersten ◽  
A. J. Rutten ◽  
A. E. Vedig
Keyword(s):  
Endotracheal Tube ◽  
Flow Rate ◽  
Pressure Support ◽  
Work Of Breathing ◽  
Inspiratory Flow ◽  
Inspiratory Flow Rate ◽  
Respiratory Muscle Fatigue ◽  
Tube Size ◽  
Endotracheal Tubes ◽  
Endotracheal Tube Size

Breathing through an endotracheal tube, connector, and ventilator demand valve imposes an added load on the respiratory muscles. As respiratory muscle fatigue is thought to be a frequent cause of ventilator dependence, we sought to examine the efficacy of five different ventilators in reducing this imposed work through the application of pressure support ventilation. Using a model of spontaneous breathing, we examined the apparatus work imposed by the Servo 900-C, Puritan Bennett 7200a, Engstrom Erica, Drager EV-A or Hamilton Veolar ventilators, a size 7.0 and 8.0 mm endotracheal tube, and inspiratory flow rates of 40 and 60 l/min. Pressure support of 0, 5, 10, 15, 20 and 30 cm H2O was tested at each experimental condition. Apparatus work was greater with increased inspiratory flow rate and decreased endotracheal tube size, and was lowest for the Servo 900-C and Puritan Bennett 7200a ventilators. Apparatus work fell in a curvilinear fashion when pressure support was applied, with no major difference noted between the five ventilators tested. At an inspiratory flow rate of 40 l/min, a pressure support of 5 and 8 cm H2O compensated for apparatus work through size 8.0 and 7.0 endotracheal tubes and the Servo 900-C and Puritan Bennett 7200a ventilators. However, the maximum negative pressure was greater for the Servo 900-C. The added work of breathing through endotracheal tubes and ventilator demand valves may be compensated for by the application of pressure support. The level of pressure support required depends on inspiratory flow rate, endotracheal tube size, and type of ventilator.

Clinical Significance of Nasal Peak Inspiratory Flow Rate in Patients with Chronic Cough

1999 ◽  
Vol 46 (5) ◽  
pp. 654
Author(s):  
Chang Hyeok An ◽  
Byung Hun Lee ◽  
Yong Bum Park ◽  
Jae Chul Choi ◽  
Hyun Suk Jee ◽  
...  
Keyword(s):  
Clinical Significance ◽  
Flow Rate ◽  
Chronic Cough ◽  
Inspiratory Flow ◽  
Inspiratory Flow Rate ◽  
Peak Inspiratory Flow ◽  
Nasal Peak Inspiratory Flow ◽  
Peak Inspiratory Flow Rate

PREDICTORS OF SUBOPTIMAL PEAK INSPIRATORY FLOW RATE IN PATIENTS WITH COPD: ANALYSES FROM THE REVEFENACIN PHASE-3 PROGRAM

CHEST Journal ◽  
2019 ◽  
Vol 156 (4) ◽  
pp. A1171-A1172
Author(s):  
Jill Ohar ◽  
FCCP ◽  
Donald Mahler ◽  
Chris Barnes ◽  
Glenn Crater
Keyword(s):  
Flow Rate ◽  
Inspiratory Flow ◽  
Inspiratory Flow Rate ◽  
Phase 3 ◽  
Peak Inspiratory Flow ◽  
Peak Inspiratory Flow Rate

Influence of inspiratory flow rate and frequency on O2 cost of resistive breathing in humans

1988 ◽  
Vol 65 (2) ◽  
pp. 760-766 ◽  
Author(s):  
D. S. Dodd ◽  
P. W. Collett ◽  
L. A. Engel
Keyword(s):  
Flow Rate ◽  
Duty Cycle ◽  
Normal Subjects ◽  
Work Rate ◽  
Inspiratory Flow ◽  
Inspiratory Flow Rate ◽  
Contraction Frequency ◽  
Mouth Pressure ◽  
Resistive Breathing ◽  
Residual Capacity

We examined the combined effect of an increase in inspiratory flow rate and frequency on the O2 cost of inspiratory resistive breathing (VO2 resp). In each of three to six pairs of runs we measured VO2 resp in six normal subjects breathing through an inspiratory resistance with a constant tidal volume (VT). One of each pair of runs was performed at an inspiratory muscle contraction frequency of approximately 10/min and the other at approximately 30/min. Inspiratory mouth pressure was 45 +/- 2% (SE) of maximum at the lower contraction frequency and 43 +/- 2% at the higher frequency. Duty cycle (the ratio of contraction time to total cycle time) was constant at 0.51 +/- 0.01. However, during the higher frequency runs, two of every three contractions were against an occluded airway. Because VT and duty cycle were kept constant, mean inspiratory flow rate increased with frequency. Careful selection of appropriate parameters allowed the pairs of runs to be matched both for work rate and pressure-time product. The VO2 resp did not increase, despite approximately threefold increases in both inspiratory flow rate and contraction frequency. On the contrary, there was a trend toward lower values for VO2 resp during the higher frequency runs. Because these were performed at a slightly lower mean lung volume, a second study was designed to measure the VO2 resp of generating the same inspiratory pressure (45% maximum static inspiratory mouth pressure at functional residual capacity) at the same frequency but at two different lung volumes. This was achieved with a negligibly small work rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of changes in inspiratory flow rate on cough responses to inhaled capsaicin

1991 ◽  
Vol 81 (s25) ◽  
pp. 539-542 ◽  
Author(s):  
M. J. Barros ◽  
S. L. Zammattio ◽  
P. J. Rees
Keyword(s):  
Citric Acid ◽  
Confidence Interval ◽  
Flow Rate ◽  
Negative Relationship ◽  
Random Order ◽  
Inspiratory Flow ◽  
Inspiratory Flow Rate ◽  
Flow Rates ◽  
Cough Response ◽  
The Difference

1. Twelve non-smoking subjects inhaled capsaicin at three different inspiratory flow rates: 50, 100 and 150 litres/min. Capsaicin was delivered by a breath-actuated dosimeter; inhalations consisted of 0.21–13.6 nmol of capsaicin in doubling amounts given in random order. 2. The mean number of coughs per challenge decreased with increasing inspiratory flow rate. The difference in cough numbers were significant: 7.7 (95% confidence interval 2.5–12.8) for 50 versus 100 litres/min and 10.9 (95% confidence interval 5.0–16.9) for 100 versus 150 litres/min. 3. On a separate day, a cough threshold was measured by giving increasing doses of citric acid that were inhaled at 50 litres/min. There was a positive correlation between the sensitivity to capsaicin and the cough threshold to citric acid (r = 0.69, P = 0.01), and also between the cough latencies (r = 0.67, P = 0.02). 4. The negative relationship between the cough response and the inspiratory flow rate may be caused by increased laryngeal deposition at lower inspiratory flow rates. 5. These results are compatible with a similar anatomical distribution of cough receptors for capsaicin and citric acid. 6. These results suggest that changes in inspiratory flow rate may affect the results of cough challenges.

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