Biomaterial Database

Measurement of pulmonary capillary blood flow by a nitrous oxide rebreathing technique. 1986

T Stokke, and H Burchardi, and H Angerer, and I Hensel

Measurements of pulmonary capillary blood flow by a nitrous oxide rebreathing technique (QN2O) were performed in 21 anesthetized and artificially ventilated minipigs with normal lungs and in nine minipigs with thrombin-induced (75-150 U kg-1 h-1) lung pathology. QN2O was calculated with the Hook-Meyer-formula and compared to cardiac output measurements (thermodilution, QT, or direct Fick's principle, QFick). The coefficient of variation in double QN2O measurements was 0.05. If the tidal volume to dead space ration (VD/VT) is normal, the nitrous oxide method works well, but when the efficacy of ventilation worsens, this gas uptake method fails to detect the circulation of the poorly ventilated parts of the lung. The mean ratio QN2O/QFick in pigs with normal lungs (58 measurements) was 1.00 +/- 0.10 (mean +/- s.d.). During thrombin infusion, the mean ratio QN2O/QT was 0.84 +/- 0.17 (n = 49). After corrections for shunt perfusion (Qs), the mean ration QN2O/(QT-Qs) was 0.89 +/- 0.17 (n = 49). QN2O/QT-Qs) decreased with increasing VD/VT. In measurements during thrombin infusion with VD/VT less than 0.33, the mean ratio QN2O/(QT-Qs) was 0.97 +/- 0.11 (n = 21), with a VD/VT between 0.33 and 0.44, the mean ratio QN2O (QT-QS) was 0.90 +/- 0.08 (n = 20), and with a VD/VT greater than or equal to 0.45, this ratio was 0.62 +/- 0.18 (n = 8). In the presence of only moderate functional inhomogeneities, this noninvasive rebreathing method will offer reliable data on pulmonary perfusion.

UI	MeSH Term	Description	Entries
D008171	Lung Diseases	Pathological processes involving any part of the LUNG.	Pulmonary Diseases,Disease, Pulmonary,Diseases, Pulmonary,Pulmonary Disease,Disease, Lung,Diseases, Lung,Lung Disease
D008297	Male		Males
D008962	Models, Theoretical	Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Experimental Model,Experimental Models,Mathematical Model,Model, Experimental,Models (Theoretical),Models, Experimental,Models, Theoretic,Theoretical Study,Mathematical Models,Model (Theoretical),Model, Mathematical,Model, Theoretical,Models, Mathematical,Studies, Theoretical,Study, Theoretical,Theoretical Model,Theoretical Models,Theoretical Studies
D009609	Nitrous Oxide	Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.	Laughing Gas,Nitrogen Protoxide,Gas, Laughing,Oxide, Nitrous
D011652	Pulmonary Circulation	The circulation of the BLOOD through the LUNGS.	Pulmonary Blood Flow,Respiratory Circulation,Circulation, Pulmonary,Circulation, Respiratory,Blood Flow, Pulmonary,Flow, Pulmonary Blood,Pulmonary Blood Flows
D002196	Capillaries	The minute vessels that connect arterioles and venules.	Capillary Beds,Sinusoidal Beds,Sinusoids,Bed, Sinusoidal,Beds, Sinusoidal,Capillary,Capillary Bed,Sinusoid,Sinusoidal Bed
D002302	Cardiac Output	The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).	Cardiac Outputs,Output, Cardiac,Outputs, Cardiac
D005260	Female		Females
D000764	Anesthesia, Closed-Circuit	Inhalation anesthesia where the gases exhaled by the patient are rebreathed as some carbon dioxide is simultaneously removed and anesthetic gas and oxygen are added so that no anesthetic escapes into the room. Closed-circuit anesthesia is used especially with explosive anesthetics to prevent fires where electrical sparking from instruments is possible.	Anesthesia, Rebreathing,Closed-Circuit Anesthesia,Anesthesia, Closed Circuit,Anesthesias, Closed-Circuit,Anesthesias, Rebreathing,Closed Circuit Anesthesia,Closed-Circuit Anesthesias,Rebreathing Anesthesia,Rebreathing Anesthesias
D000768	Anesthesia, General	Procedure in which patients are induced into an unconscious state through use of various medications so that they do not feel pain during surgery.	Anesthesias, General,General Anesthesia,General Anesthesias