Relative tidal volume and respiratory airflow estimation using tracheal sound and movement during sleep

A nasal flowmeter suitable for preterm infants is described. It is made from a commercially available nasal cannula and 400-mesh stainless steel screen. Low dead space (0.35 ml) and low resistance (1.3 cmH2O . 100 ml-1 . s) are advantages. Light weight and compact design have eliminated the need for extensive restraint of the subject. Also, the investigator need not hold the flowmeter in place. These features make accurate measurement of respiratory airflow and tidal volume possible during polygraphic monitoring studies lasting several hours.

Download Full-text

Two-sidearm tracheal cannula for respiratory airflow measurements in small animals

Journal of Applied Physiology ◽

10.1152/jappl.1983.55.1.250 ◽

1983 ◽

Vol 55 (1) ◽

pp. 250-253 ◽

Cited By ~ 84

Author(s):

J. P. Mortola ◽

A. Noworaj

Keyword(s):

Tidal Volume ◽

Linear Response ◽

Flow Resistance ◽

Small Volume ◽

The Body ◽

Small Animals ◽

Newborn Rats ◽

Mean Flow ◽

Tracheal Cannula ◽

Respiratory Airflow

We have investigated the possibility of using a two-sidearm tracheal cannula for measurements of respiratory airflow. Measurements of mean flow and tidal volume using four such cannulas (0.7, 1.5, 1.8, and 2.5 mm ID) are described. They have a linear response up to flows of 6, 10, 12, and 28 ml X s-1, respectively, that correspond to 100 ml X s-1 X kg-1 or more, depending on the body size of the animals (15-350 g) in which they could be used. These characteristics, coupled with small volume and flow resistance, make the use of these cannulas as pneumotachographs a suitable and very practical way of measuring mean airflow and tidal volume in anesthetized small animals, ranging in size from newborn rats to newborn puppies.

Download Full-text

Increased cardiac microvascular permeability and activation of cardiac endothelial nitric oxide synthase in high tidal volume ventilation-induced lung injury

Asian Biomedicine ◽

10.2478/abm-2010-0004 ◽

2010 ◽

Vol 4 (1) ◽

pp. 27-36

Author(s):

Ming-Jui Hung ◽

Ming-Yow Hung ◽

Wen-Jin Cherng ◽

Li-Fu Li

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Lung Injury ◽

Tidal Volume ◽

Endothelial Nitric Oxide Synthase ◽

Microvascular Permeability ◽

Akt Phosphorylation ◽

Enos Phosphorylation ◽

Oxide Synthase ◽

Endothelial Nitric Oxide

Abstract Background: Positive pressure ventilation with large tidal volumes has been shown to cause lung injury via the serine/threonine kinase-protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS)-pathways. However, the effects of high tidal volume (VT) ventilation on the heart are unclear. Objectives: Evaluate the effect of VT ventilation on the cardiac vascular permeability and intracellular Akt and eNOS signaling pathway. Methods: C57BL/6 and Akt knock-out (heterozygotes, +/−) mice were exposed to high VT (30 mL/kg) mechanical ventilation with room air for one and/or five hours. Results: High VT ventilation increased cardiac microvascular permeability and eNOS phosphorylation in a timedependent manner. Serum cardiac troponin I was increased after one hour of high VT ventilation. Cardiac Akt phosphorylation was accentuated after one hour and attenuated after five hours of high VT ventilation. Pharmacological inhibition of Akt with LY294002 and high VT ventilation of Akt+/− mice attenuated cardiac Akt phosphorylation, but not eNOS phosphorylation. Conclusion: High VT ventilation increased cardiac myocardial injury, microvascular permeability, and eNOS phosphorylation. Involvement of cardiac Akt in high VT ventilation was transient.

Download Full-text