Biomaterial Database

Factors determining end-expiratory alveolar pressure after cardiac surgery. 1999

R Fletcher, and P Foster, and S Thornton

Central Manchester Hospitals NHS Trust, Manchester, UK.

Intrinsic positive end-expiratory pressure can occur when the sternum is closed following cardiac surgery, causing anaesthetic and surgical problems. We measured intrinsic positive end-expiratory pressure after sternal closure in two studies of patients undergoing coronary artery bypass grafting with the same anaesthetic regime. In one, patients were ventilated at 10 breaths min-1, in the other they were randomized to be ventilated at 10 or 20 breaths min-1. After sternal closure, intrinsic positive end-expiratory pressure increased significantly, especially in patients in whom it had been present before sternotomy. Multiple linear regressions with the pooled data from the studies showed that intrinsic positive end-expiratory pressure was positively correlated with ventilatory rate (P < 0.005), age (P < 0.005) and Body Mass Index (P < 0.0005), and negatively with FEV1, as percentage of predicted (P < 0.01). There was no correlation between intrinsic positive end-expiratory pressure and a history of smoking. As there was no difference in expiratory resistance between patients ventilated at the two different rates, any effect on intrinsic positive end-expiratory pressure of the higher ventilatory rates could have been due only to the shorter expiratory time.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D011183	Postoperative Complications	Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.	Complication, Postoperative,Complications, Postoperative,Postoperative Complication
D012121	Respiration, Artificial	Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).	Ventilation, Mechanical,Mechanical Ventilation,Artificial Respiration,Artificial Respirations,Mechanical Ventilations,Respirations, Artificial,Ventilations, Mechanical
D005260	Female		Females
D005541	Forced Expiratory Volume	Measure of the maximum amount of air that can be expelled in a given number of seconds during a FORCED VITAL CAPACITY determination . It is usually given as FEV followed by a subscript indicating the number of seconds over which the measurement is made, although it is sometimes given as a percentage of forced vital capacity.	Forced Vital Capacity, Timed,Timed Vital Capacity,Vital Capacity, Timed,FEVt,Capacities, Timed Vital,Capacity, Timed Vital,Expiratory Volume, Forced,Expiratory Volumes, Forced,Forced Expiratory Volumes,Timed Vital Capacities,Vital Capacities, Timed,Volume, Forced Expiratory,Volumes, Forced Expiratory
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000367	Age Factors	Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.	Age Reporting,Age Factor,Factor, Age,Factors, Age
D000368	Aged	A person 65 years of age or older. For a person older than 79 years, AGED, 80 AND OVER is available.	Elderly
D000403	Airway Resistance	Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.	Airway Resistances,Resistance, Airway,Resistances, Airway