Intravenous Anaesthesia - Barbiturates, Benzodiazepines & Propofol MCQs

The principal clinical uses of thiopental (3–5 mg/kg IV) or methohexital (1–5 mg/kg IV) is for induction of anaesthesia (unconsciousness), which usually occurs in less than 30 seconds. Patients may experience a garlic or onion taste after administration. Barbiturates such as methohexital (20–30 mg/kg) may be administered per rectum to facilitate induction of anaesthesia in mentally challenged and uncooperative paediatric patients. When a barbiturate is administered with the goal of neuroprotection, an isoelectric EEG indicating maximal reduction of CMR O 2 has traditionally been used as the end point. Reference : LANG’ Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 25- General Anaesthetics by Dr. Helge Eilers,MD & Dr. Spencer Yost,MD. Page no. 442

Benzodiazepines commonly used in the perioperative period include midazolam, lorazepam, and less frequently, diazepam. Benzodiazepines are unique among the group of intravenous anaesthetics in that their action can readily be terminated by administration of their selective antagonist, flumazenil. Their most desired effects are anxiolysis and anterograde amnesia, which are extremely useful for premedication. Reference : LANG’ Basic & clinical pharmacology by Bertram G. Katzung, Susen B. Masters and Anthony J. Trevor 12 th edition. Chapter 25- General Anaesthetics by Dr. Helge Eilers,MD & Dr. Spencer Yost,MD. Page no. 442

Ischemic changes in leads II, III and aVF suggest right coronary artery disease, leads I and aVL monitor the circumflex artery distribution and leads V3 to V5 look at the distribution of the left anterior descending artery . Reference: objective anaesthesia review 4th edition pg 18

The pain of labour arises from Contraction of the myometrium against the resistance of the cervix and perineum , Progressive dilation of the cervix and lower uterine segment Stretching and compression of pelvic and perineal structures Pain during the first stage of labour is → primarily visceral pain resulting from uterine contractions and cervical dilation It is usually initially confined to the T11-T12 dermatomes during the → latent phase , but eventually involves the T10-L1 dermatomes as labour enters → the active phase . Reference: Anaesthesia Review a Comprehensive Texbook 5th Edition Chapter 12 Page No.110

Cardiovascular diseases are more prevalent in the geriatric than general population Still, it is important to distinguish between changes in physiology that normally accompany aging and the pathophysiology of diseases common in the geriatric population Changes in the cardiovascular system that accompany aging include Decreased vascular compliance Decreased myocardial compliance Decreased autonomic responsiveness Myocardial fibrosis Myocardial calcification of the valves Reference: Anaesthesia Review a Comprehensive Texbook 5th Edition Chapter 24 Page No 214.

Basal and maximal oxygen consumption declines with age After reaching peak weight at about age 60 years , most men and women begin losing weight ; the average elderly man and woman weigh less than their younger counterparts Heat production decreases , heat loss increases, and hypothalamic temperature-regulating centres may reset at a lower level. Reference: Anaesthesia Review a Comprehensive Texbook 5th Edition Chapter 24 Page No.217.

Measures to prevent perioperative hypoxia in elderly patients include a Longer Preoxygenation period prior to induction Increased inspired oxygen concentrations during anaesthesia Positive end-expiratory pressure Pulmonary toilet Reference: Anaesthesia Review a Comprehensive Texbook 5th Edition Chapter 24 Page No 222.

The elderly patient with diastolic dysfunction may poorly tolerate perioperative fluid administration, resulting in Elevated left ventricular end-diastolic pressure Pulmonary congestion. Diminished cardiac reserve in many elderly patients may be manifested as exaggerated drops in blood pressure during induction of general anesthesia Reference: Anaesthesia Review a Comprehensive Texbook 5th Edition Chapter 24 Page No. 214, 215 , 216.