RIGHT LUNGPEEP is an adjuvunt to the mode ventilation used in cases where the FRC is reduced. At the end of expiration, the PEEP exerts pressure to oppose passive emptying of the lung and to keep the airway pressure above the atmospheric pressure. The presence of PEEP opens up collapse or unstable alveoli and increases the FRC and surface area for gas exchange, thus reducing the size of the shunt. Thus, if a large shunt is found to exist based on the estimation from 100% FiO2 (see above), then PEEP can be considered and the FiO2 can be lowered (<60%), to maintain adequate PaO2, thus reducing the risk of oxygen toxicity.
In addition to treating a shunt, PEEP is also therapeutic in decreasing the work of breathing. In pulmonary physiology, compliance is a measure of the "stiffness" of the lung and chest wall. The mathematical formula for compliance (C) = change in volume / change in pressure. Therefore, a higher compliance means that only small increases in pressure can lead to large increases in volume, which means the work of breathing is reduced. As the FRC increases with PEEP, the compliance also increases, since the partially inflated lung takes less energy to inflate further.
Indications
PEEP is a cardiodepressant and can cause severe hemodynamic consequences through decreasing venous return to the right heart and decreasing right ventricular. As such, it should be judiciously used and is indicated in two circumstances.
If used, PEEP is usually set with the minimal positive pressure to maintain an adequate PaO2 with a safe FiO2. As PEEP increase intrathoracic pressure, there can be a resulting decrease in venous return and decrease in cardiac output. A PEEP of less than 10 cmH2O is usually safe if intravascular volume depletion is absent. Older literature recommended routine placement of a Swan-Ganz catheter if the amount of PEEP used is > 10 cmH2 for hemodynamic monitoring. More recent literature has failed to find outcome benefits with routine PA catheterization when compaired to simple central venous pressure monitoring.[2] If cardiac output measurement is required, minimally invasive techniques, such as esophageal doppler monitoring or arterial waveform contour monitoring may be sufficient alternatives.[3][4] PEEP should be withdrawn from a patient until adequate PaO2 can be maintained with a FiO2 < 40%. When withdrawing, it is decreased through 1-2 cmH2O decrements while monitoring hemoglobin-oxygen saturations. Any unacceptable hemoglobin-oxygen saturation should prompt reinstitution of the last PEEP level that maintained good saturation.
In active pulmonary TB, infiltrates or consolidations and/or cavities are often seen in the upper lungs with or without mediastinal or hilar lymphadenopathy. However, lesions may appear anywhere in the lungs. In HIV and other immunosuppressed persons, any abnormality may indicate TB or the chest X-ray may even appear entirely normal.
Old healed tuberculosis usually presents as pulmonary nodules in the hilar area or upper lobes, with or without fibrotic scars and volume loss. Bronchiectasis and pleural scarring may be present.
Nodules and fibrotic scars may contain slowly multiplying tubercle bacilli with the potential for future progression to active tuberculosis. Persons with these findings, if they have a positive tuberculin skin test reaction, should be considered high-priority candidates for treatment of latent infection regardless of age. Conversely, calcified nodular lesions (calcified granuloma) pose a very low risk for future progression to active tuberculosis.
Abnormalities on chest radiographs may be suggestive of, but are never diagnostic of, TB. However, chest radiographs may be used to rule out the possibility of pulmonary TB in a person who has a positive reaction to the tuberculin skin test and no symptoms of disease.
A medical examination is mandatory for all refugees coming to the U.S. and all applicants outside the U.S. applying for an immigrant visa. The purpose of the medical examination is to identify applicants with inadmissible health-related conditions such as active tuberculosis. Outside the U.S., medical examinations are performed by approximately 400 physicians (panel physicians) selected by United States Department of State consular officials. In the U.S., medical examinations are performed by approximately 3,000 physicians (civil surgeons) designated by district directors of the U.S. Citizenship and Immigration Services. Guidelines were developed by the Centers for Disease Control and Prevention (CDC).
The chest X-ray and classification worksheet is designed to group findings into categories based on their likelihood of being related to TB or non-TB conditions needing medical follow-up (either at the time of the chest X-ray or after resettlement).
These are films that are completely normal, with no identifiable cardiothoracic or musculoskeletal abnormality.aa
This category comprises all findings typically associated with active pulmonary TB. An applicant with any of the following findings must submit sputum specimens for examination. Infiltrate or consolidation—Opacification of airspaces within the lung parenchyma. Consolidation or infiltrate can be dense or patchy and might have irregular, ill-defined, or hazy borders.
This category includes findings that are suggestive of prior TB, that is inactive. It must be remembered that assessments of the activity of TB cannot be made accurately on the basis of a single radiograph alone. If there is any question of active TB, sputum smears must be obtained. Furthermore, if the applicant has any signs or symptoms of TB, sputum smears must be obtained. Obtaining sputum smears is necessary if there is any question of active TB. Therefore, any applicant might have findings grouped in this category, but still have active TB as suggested by
This category includes findings that suggest the need for a follow-up evaluation for non-TB conditions either at the time of the chest X-ray or after resettlement of the applicant in the United States.
This category includes findings that are minor and not suggestive of TB disease. These findings require no follow-up evaluation after resettlement of the applicant.
Additional X-ray images
These are links to pictures copyrighted by the websites...
