Archive for the 'Heart Surgery' Category

15 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Conclusion

The relationship between Pres,w and V was curvilinear (Fig 2 and 3), showing an upward concavity in all patients before surgery. Similar data have been reported previously in animals and humans. Figure 3 shows that Rw decreases with increasing expiratory flow, and furthermore, it is very similar in both groups of patients. Indeed, according to […]

14 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Outcome

In the present study, the relationship between Pres,L and V was curvilinear (Fig 2), showing an upward concavity, in line with previous reports indicating that with increasing flow, pulmonary resistive pressure losses augment disproportionately. The mean a coefficient was statistically higher in valvular patients than in ischemic ones, whereas b was similar in both groups. These results would imply […]

13 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Heart disease

In the present study, we used the SBM in order to obtain the values of resistive pressures within the entire tidal range of expiratory flows. The study of the resistive behavior of the respiratory system, lung, and chest wall during passive expirations may be performed by fitting power or linear functions to the corresponding resistive […]

12 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Partitioning of Rrs

As previously reported, an increase in Ers after surgery was also observed. In ischemic patients, this was consequent to a significant rise in EL. On the other hand, in valvular subjects, EL did not change. The Ew remained unaffected in both groups. The increase in EL could be explained by some alterations associated with cardiac […]

11 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Discussion

Cardiac surgery under CPB is a condition that may affect lung and chest wall mechanics. However, studies in order to partition Ers and Rrs into their lung and chest wall components throughout relaxed expiration in this condition have not been reported hitherto. For this purpose, the SBM was, for the first time, applied to humans. […]

10 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Results

Table 2 shows the individual mean values (± SD) of five elastance determinations in all patients before and after surgery. Preoperatively, patients with valvular disease exhibited significantly higher values of Ers and EL than the corresponding values in those with ischemic heart disease. The Ew was similar in both groups. The Ers and Ew were […]

09 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Properties of respiratory system

After releasing the occlusion, the resistive properties of respiratory system, lung, and chest wall were computed throughout the ensuing relaxed expiration. Briefly, after the first moments of a relaxed expiration, accelerative pressures become negligible, and very nearly all the recoil pressure of the lungs and chest wall (Pel,rs) was available to overcome the total expiratory […]

08 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Data Analysis

All variables were registered on a pen recorder. Flow, Ptr, PL, and Pes signals were also fed through an eight-bit analog-to-digital converter (60 Hz sampling frequency) into a microcomputer. Volume (V) was obtained both by electronic integration (on the pen recorder) and by digital integration of the flow signal. All variables were stored on magnetic […]

07 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery: Material and Methods

Twelve randomly selected patients (24 to 68 years old) scheduled for elective cardiac surgery for either correcting valvular dysfunctions (six patients) or for coronary bypass were investigated. The research was approved by our institutional ethics committee and informed consent was obtained from all patients. Subjects’ characterization, preoperative hemodynamic data, CPB, and surgery times are shown […]

06 Oct

Expiratory Mechanics Before and After Uncomplicated Heart Surgery

Although several studies on respiratory mechanics related to cardiac surgery in humans have been reported, there are some important aspects still unexplored. Most of the previous works assessed total respiratory system mechanics and a comprehensive study in order to describe respiratory system, lung and chest wall mechanical properties during the entire relaxed tidal expiration has […]

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