Ⓜ️NEMO #ANESTHESIA IMPLICATIONS IN SARCOIDOSIS: “SARC” 🔸🔸🔸🔸

Posted on July 28, 2017 by Dr Unnikrishnan Prathapadas

🔻'S ound box(=larynx)' involvement
🔻Arrhythmia, Altered PFT-ECG-ECHO are key points to be searched for
🔻R enal impairement
🔻C alcium increased , Cardiac & CNS involvement

▪️ADDITIONAL POINTS▪️

PULMONARY INVOLVEMENT
➖➖➖➖➖➖➖➖➖➖

🔑PFT may be impaired

🔑CXR may show bilateral hilar lymphadenopathy with increased reticular shadowing in the lung ﬁelds

🔑Look for evidence of pulmonary hypertension

🔑If there is widespread pulmonary involvement and the patient is symptomatic, lung function tests, including blood gases, should be performed.

HYPERCALCEMIA
➖➖➖➖➖➖

🔑It is secondary to the production of excess 1,25- dihydroxycholecalciferol. Nephrocalcinosis and renal failure may occur . So establish treatment for hypercalcemia

CARDIAC INVOLVEMENT
➖➖➖➖➖➖➖➖➖

🔑Cardiac involvement carries a poor prognosis and it's diagnosis is of anaesthetic importance. Cardiac disease may be unexpected, and can occur even in young, previously asymptomatic patients.

🔑The pathological lesions can be diffuse or focal. Localised granulomas and ﬁbrous scarring most commonly occur in the basal portion of the ventricular septum and left ventricular wall. These lesions will be asymptomatic unless they happen to involve the conducting system,in which case arrhythmias or conduction defects occur. Less commonly,the distribution of granulomas may be widespread,and they may coalesce to produce diffuse interstitial ﬁbrosis. The resulting hypokinesia and subsequent heart failure is clinically indistinguishable from other cardiomyopathies .

🔑Pericardial effusions may also occur.Myocardial imaging showed that the majority of these had an inﬁltrative cardiomyopathy.

🔑In those patients diagnosed as having cardiac involvement,the signs in order of frequency of presentation were:

🔹complete heart block
🔹ventricular ectopics or ventricular tachycardia
🔹myocardial disease causing heart failure
🔹sudden death
🔹ﬁrst-degree heart block or bundle branch block.

🔑In most of the patients with complete heart block and sarcoid the heart block was the ﬁrst sign of the disease

🔑The sudden onset of complete heart block during anaesthesia can occur

🔑Difficulties with pacemaker management can be a feature of cardiac sarcoidosis. Patients with advanced disease may have automatic implantable cardioverter deﬁbrillators inserted

🔑A preoperative ECG is essential, even in young patients. An ECHO also may be ordered. If there is evidence of a conduction defect, a temporary pacemaker should be inserted before anaesthesia.

CNS INVOLVEMENT
➖➖➖➖➖➖➖

🔑 Central nervous system sarcoid also carries a poor prognosis.

🔑 Presentation can vary widely and includes cranial nerve palsies,peripheral neuropathy,epilepsy,and cerebellar ataxia

AIRWAY INVOLVEMENT
➖➖➖➖➖➖➖➖

🔑 Laryngeal sarcoidosis : the commonest lesion reported is an oedematous, pale,diffuse enlargement of the supraglottic structures

🔑 Infiltration of the airway may cause obstructive sleep apnoea

🔑 So need for an ENT evaluation preoperatively should be considered

DIAGNOSIS :
➖➖➖➖

🔑 can be made on biopsy of a skin lesion,or lung and bronchial biopsy via a ﬁbreoptic bronchoscope.

🔑 The Kveim test has a high positivity in the active stages, but is lower in the chronic disease.

🔑 Serum angiotensin- converting enzyme (ACE) level is an indicator of sarcoid activity

🔑 serum calcium and 24-h urinary calcium levels may also be increased in active sarcoid.

🔑 Treatment of active disease may include corticosteroids, immunosuppressants, methotrexate,NSAIDS,and calcium chelating agents.

Reference: Medical disorders and anaesthetic problems , Rosemary Mason , Anesthesia Databook , A Perioperative and Peripartum Manual , 3/e

#sarcoidosis , #mnemonics , #MedicalMnemonics , #anaesthesia

RESPIRATORY PHYSIOLOGY IN THE ELDERLY 👴🏻

Posted on July 25, 2017 by Dr Unnikrishnan Prathapadas

🍃Ventilatory responses to hypoxia and hypercapnia are impaired secondary to reduced central nervous system activity.

🍃The respiratory depressant effects of benzodiazepines, opioids, and volatile anesthetics are exaggerated.

🍃These changes compromise the usual protective responses against hypoxemia after anesthesia and surgery in elderly patients.

🍃The loss of elastic recoil combined with altered surfactant production leads to an increase in lung compliance.

🍃Increased compliance leads to limited maximal expiratory flow and a decreased ventilatory response to exercise.

🍃Loss of elastic elements within the lung is associated with enlargement of the respiratory bronchioles and alveolar ducts, and a tendency for early collapse of the small airways on exhalation.

🍃There also is a progressive loss of alveolar surface area secondary to increases in size of the interalveolar pores of Kohn. This results in increased anatomic dead space, decreased diffusing capacity, and increased closing capacity all leading to impaired gas exchange.

🍃Loss of height and calcification of the vertebral column and rib cage lead to a typical barrel chest appearance with diaphragmatic flattening.

🍃The flattened diaphragm is mechanically less efficient, and function is impaired further by a significant loss of muscle mass associated with aging. Functionally, the chest wall becomes less compliant, and work of breathing is increased.

🍃Total lung capacity is relatively unchanged.

🍃Residual volume increases by 5% to 10% per decade.

🍃Vital capacity decreases.

🍃Closing capacity increases with age.

🍃Functional residual capacity (FRC) is determined by the balance between the inward recoil of the lungs and the outward recoil of the chest wall. FRC increases by 1%–3% per decade because at relaxed end expiration, the rate of decrease in lung recoil with aging exceeds that of the rate of increase in chest wall stiffness.

🍃In younger individuals, closing capacity is below functional residual capacity. At 44 years of age, closing capacity equals functional residual capacity in the supine position, and at 66 years of age, closing capacity equals functional residual capacity in the upright position.

🍃When closing capacity encroaches on tidal breathing, ventilation-perfusion mismatch occurs.

🍃When functional residual capacity is below closing capacity, shunt increases, and arterial oxygenation decreases. This results in impairment of preoxygenation. Increased closing capacity in concert with depletion of muscle mass causes a progressive decrease in forced expiratory volume in 1 second by 6% to 8% per decade.

🍃Increases in pulmonary vascular resistance and pulmonary arterial pressure occur with age and may be secondary to decreases in cross-sectional area of the pulmonary capillary bed. Hypoxic pulmonary vasoconstriction is blunted in elderly individuals and may cause difficulty with one-lung ventilation.

Ref: Geriatric Anesthesia 2/e , Miller’s Anesthesia 7/e

#Physiology , #Anesthesia , #Geriatrics