Anatomy and Physiology Flashcard 1

C. Rationale: The survival reflex helps protect the vital organs from hypoxemia. Blood vessels to the extremities and nonessential organs will constrict in the presence of poor oxygenation to favor blood flow to the brain, heart, and kidneys.

D. Rationale: Robin sequence is a congenital disorder producing an underdeveloped mandible that forces the tongue to push posteriorly against the posterior hypopharynx and cause upper airway obstruction. It can be diagnosed by ultrasound during prenatal check-ups. The presence of Robin sequence should alert neonatal resuscitation teams to be ready to provide assisted ventilation to the patient.

C. Rationale: A newly born with trisomy 21 (Down syndrome) will typically have a large tongue, making it difficult to keep the airway patent without using an advanced airway. Early in the resuscitation sequence, a laryngeal mask is preferred rather than performing endotracheal intubation. The clinician should not use laryngeal masks in preterm neonates and those weighing < 2,000 grams.

D. Rationale: The preterm patient has profoundly limited glucose reserves that may lead to hypoglycemia even with minimal instances of stress.

D. Rationale: Medical conditions that can cause acute blood loss to the newly born can diminish the perfusion of blood to the myocardium, which will cause systolic dysfunction and lead to cardiac arrest. Epinephrine is given to strengthen cardiac contractility.

B. Rationale: Delayed cord clamping has beneficial effects such as increasing the blood volume and blood pressure to sustain the demands of the neonate, reduced incidence of intraventricular hemorrhage, less need for immediate postpartum blood transfusion, and decreased incidence of necrotizing enterocolitis.

C. Rationale: The positive end-expiratory pressure is the pressure remaining in the lungs between each breath during assisted ventilation. The peak inspiratory pressure is the highest pressure administered to the neonate within each breath. The plateau pressure is the air pressure applied to the alveoli at the end of inspiration, and the inspiratory time is the duration of the inspiratory phase with each assisted breath.

C. Rationale: The fetal circulation mainly involves the placenta for gas exchange to occur, and it does not involve the lungs. There are conduits or shunts in the heart that remain open (ductus arteriosus, ductus venosus, and the foramen ovale) so that fetal circulation bypasses the nonfunctioning lungs creating a right-to-left shunt. As the newly born takes its first breath, these shunts must close, causing a transition from right-to-left shunting to left-to-right shunting.

D. Rationale: The work of breathing is severely compromised in the preterm infant due to poor lung compliance. Lung compliance is the measure of the lung’s elasticity and its ability to stretch and expand. Low lung compliance means that the lungs are stiff. Preterm patients will present with underdeveloped accessory muscles for breathing, stiff ribs, and low surfactant levels. These are attributes of poor lung compliance.

A. Rationale: Preterm newborns are prone to hypothermia because they have less subcutaneous fat, thin skin, and slower metabolic responses.