-b. direct acting vasopressors should be used in MAO therapy. Phenylephrine is the only direct-acting drug of the listed choices.
c. 5 mcg/mL
Based on a system of grams per liter, a 1: 200,000 concentration is equal to 5 mcg/mL
-b. metoclopramide (reglan) to increase gastric emptying
Diabetic patients often have gastric atony; thus, a gastrokinetic agent such as reglan may be useful to ensure an empty stomach
-b. decreased ETco2
Venous air embolism, such as seen in sitting procedures, may be detected by a reduced end expired CO2, resulting from the ventilation/perfusion mismatch.
-b. dextrose and water
Glucose containing solutions are avoided in all neurosurgical patients because they can exacerbate ischemic damage and cerebral edema (glucose is hypertonic and will draw water to the site)
-c. hyperventilation reduces brain volume by decreasing cerebral blood flow through cerebral vasoconstriction. For every millimeter of mercury change, cerebral blood flow decreases by approximately 4%.
-c. Hyperventilation to tge PaCO2 of 25 to 30 mmHg is the mainstay of acute and subacute treatment for intracranial hypertension.
-c. nitrous oxide
Most inhalation anesthetics in the absence of a pathologic process have little effect on or decrease pulmonary vascular resistance. Nitrous oxide may increase resistance, especially in patients with pulmonary hypertension.
-a. pulse oximetry
The lambert beer law relates to the observation that oxygenated and reduced hemoglobin differ in their absorption of red and infrared light. Pulse oximetry monitoring is based on this principle.
-b. SV x HR
Cardiac output is equal to stroke volume times heart rate and is expressed in “liters/minute”. The normal range is 4 to 8
-c. CI = CO/BSA
Cardiac Index is derived from the cardiac output divided by the body surface area and is expressed as “liters/minute/meters squared”. normal range is 2.5 to 4
-a. 2.5-4.2 L/min
cardiac output is derived from the cardiac output divided by body surface area and is expressed as liters per minute per meter squared
-b SVR = (MAP-CVP) X 80/CO or (MAP-CVP /CO X 80
Systemic vascular resistance is calculated from this formula
-d. 1200-1500 dynes/sec/cm-5
that is the normal SVR
-a. erratic and inacurate readings
When proprely functioning venous catheters rarely give erratic and inacurate readings; however, the other complications are always possible
-c. carotid artery
Puncture of the carotid artery is especially prominent in left internal jugular cannulation. Using the right internal jugular is safer, with less likelihood of arterial puncture.
-c. place the patient in trendelenberg position
Air embolism can be avoidied by using the trendelenberg positon to increase venous pressure, which limits the possiblity of the entrance of air through the catheter.
-c. postoperative ventilatory failure
Although muscle strength frequently seems adequate early after anesthesia and surgery, many patients with myasthenia gravis experience deterioration and require ventilatory support after surgery.
-c. intraneuronal injection
Accidentally pinning a nerve against an ajacent structure increases the likelihood of intraneuronal injection. When this occurs, the injection should be stopped and the needle re-placed
-d. ketamine
Ketamine, by releasing catecholamines supports blood pressure. Patients with cardiac tamponade are decompensated and any cardiac depressant drug may cause precipitous hypotension.
-c. FRC (functional residual capacity)
Induction of anesthesia consistantly produces a 15-20% reduction in functional residual capacity beyond which occurs in supine position.
-a. compliance is reduced as abdominal contents push up against the diaphragm
Loss of diaphragmatic tone allows abdominal contents to rise up against the diaphragm. The higher position of the diaphragm decreases lung volumes.
-c. etomidate
etomidate inhibits the conversion of cholesterol to cortisone by inhibiting conversion enzymes. This results in adrenal suppression.
-a. lateral femoral cutaneous
The lateral femoral cutaneous nerve may be entrapped in the anetrior iliac spine under the inguinal ligament resulting in numbness in the thigh.