Paediatric and Obstetric Anaesthesia MCQs

The symptoms described in this patient are consistent with severe dehydration. Thus, the vascular volume should be expanded initially with an isotonic saline solution or a colloid solution until the patient voids. When the urine output increases, potassium can be added to the IV fluids. Although glucose administration for long procedures may prevent hypoglycemia, D5W alone or with a crystalloid solution should not be used to replace fluid deficits. Reference: Davis: Smith's Anesthesia for Infants and Children, ed 8, pp 126-129.

Newborns with diaphragmatic hernia have significant respiratory difficulty. In addition to their hypoplastic lungs, persistent pulmonary hypertension is present, producing right-to-left shunting through the patent ductus arteriosus. To more appropriately administer the anesthetic, a preductal (ductus arteriosus) artery should be cannulated to monitor arterial blood gases and blood pressure. The right radial or temporal arteries arise from vessels that originate from the aorta proximal to the ductus arteriosus. The oxygen saturation monitors should be placed on the right arm as well. Reference: Hines: Stoelting's Anesthesia and Co-Existing Disease, ed 6, pp 595-596.

Cardiac stroke volume is relatively fixed by a noncompliant and immature left ventricle in neonates and infants The cardiac output is therefore very sensitive to changes in heart rate Although basal heart rate is greater than in adults Reference: E Book of Morgan and Mikhail’s 6th Edition Chapter 42 1521, 1522.

Compared with older children and adults, neonates and infants have Weaker intercostal muscles Weaker diaphragms (due to a paucity of type 1 fibres) Less efficient ventilation More horizontal and pliable ribs Protuberant abdomen Reference: E Book of Morgan and Mikhail’s 6th Edition Chapter 42 Page No 1520, 1521 .

The glottis of a premature newborn is at the level of C3, for the term newborn the level is C4, and in the adult the glottis is at the C5 level. The relatively high glottis makes intubation more difficult in the premature newborn (i.e., more tissue and less distance). Reference: Barash: Clinical Anesthesia, ed 7, p 1185; Davis: Smith's Anesthesia for Infants and Children, ed 8, p 351; Miller: Miller's Anesthesia, ed 8, pp 2757-2761.

Anesthesia for patients with EA and TEF can be safely induced with either an intravenous or volatile anesthetic. However, positive-pressure bag and mask ventilation should be avoided because it will force gas into the stomach, potentially making ventilation of the lungs more difficult. A frequently used technique to facilitate correct placement of the endotracheal tube is to advance the tube into a bronchus. While listening over the stomach, slowly withdraw the tube until breath sounds are heard over the stomach. Advance the tube until these sounds become diminished. Bronchoscopy is used by some anesthesiologists to make sure only one fistula is present and to help position the endotracheal tube. Reference: Davis: Smith's Anesthesia for Infants and Children, ed 8, pp 576-577; Hines: Stoelting's Anesthesia and Co-Existing Disease, ed 6, pp 597-598.

Correct tube size and appropriate cuff inflation is confirmed by easy passage into the larynx and the development of a gas leak at 15 to 25 cm H 2 O pressure.(which is acceptable as described in the case as leak above 20 cm of H20) No leak indicates an oversized tube or overinflated cuff that should be replaced or deflated to prevent postoperative edema, whereas an excessive leak may preclude adequate ventilation and contaminate the operating room with anesthetic gases. Reference: Morgan and Mikhail's clinical anesthesiology 6th edition, pg 914.

In infants and young children, there should be a small air leak around the endotracheal tube at peak inflation pressures of approximately 15 to 25 cm H2O. The leak test can be performed by slowly increasing the airway pressure and listening with a stethoscope over the larynx to hear when a leak develops. An air leak within this pressure range allows for adequate ventilation and reduces the incidence of postintubation croup. The most common cause of postintubation croup is a tight-fitting endotracheal tube without a leak at 30 to 40 cm H2O. Reference: Davis: Smith's Anesthesia for Infants and Children, ed 8, pp 356-357, 389-390.