15- Post operative Explains Flashcards
What is the definition of postoperative cognitive dysfunction (POCD)?
Deterioration in performance in a battery of neuropsychological tests that would be expected in less than 3.5% of controls, or long-term, possibly permanent disabling deterioration in cognitive function following surgery.
What factors are associated with late POCD?
Increasing age, emboli, and biochemical disturbances.
What factors are associated with early POCD?
Increasing age, general anesthesia rather than regional anesthesia, longer duration of anesthesia, reoperation, and postoperative infection.
How are patients identified as malnourished according to NICE guidelines?
Patients with a BMI < 18.5 kg/m² or unintentional weight loss of > 10% over 3-6 months, or patients with a BMI < 20 kg/m² and unintentional weight loss of > 5% over 3-6 months.
Who is considered at risk of malnutrition according to NICE guidelines?
Patients who have eaten nothing or very little for more than 5 days and are likely to continue eating little for another 5 days, or patients with poor absorptive capacity, high nutrient losses, or high metabolism.
When should parenteral nutrition be considered according to NICE guidelines?
Parenteral nutrition should be considered in patients with unsafe or inadequate oral intake, or in patients with a non-functional gastrointestinal tract, perforation, or inaccessibility.
What is the recommended approach for feeding patients for less than 14 days?
Feeding via a peripheral venous catheter is recommended for patients needing parenteral nutrition for less than 14 days.
What is the recommended approach for feeding patients for more than 30 days?
A tunneled subclavian line is recommended for patients needing parenteral nutrition for more than 30 days.
In what situations is continuous administration of parenteral nutrition recommended?
Continuous administration is recommended for severely unwell patients.
When should a change from continuous to cyclical feeding be considered?
If parenteral nutrition is needed for more than 2 weeks, a change from continuous to cyclical feeding should be considered.
What is the recommended approach for unwell patients in the first 24-48 hours of parenteral nutrition?
Do not give more than 50% of the daily regimen to unwell patients in the first 24-48 hours.
What is the recommendation for perioperative parenteral feeding in surgical patients?
In malnourished surgical patients with an unsafe swallow or a non-functional gastrointestinal tract, perforation, or inaccessibility, perioperative parenteral feeding should be considered.
What is circulatory support in the context of critically ill patients?
Circulatory support is provided to patients who have impaired tissue oxygenation, often as a result of circulatory shock.
What are some methods of haemodynamic monitoring for patients requiring circulatory support?
Methods of haemodynamic monitoring include regular urine output measurements, blood pressure monitoring, ECG monitoring for cardiac arrhythmias, and pulse oximeter measurements for estimating hemoglobin oxygen saturation.
How is invasive arterial blood pressure monitoring performed?
Invasive arterial blood pressure monitoring is done using an indwelling arterial line, most commonly placed in the radial artery. Care should be taken not to cannulate end arteries.
What is central venous pressure (CVP) and how is it measured?
Central venous pressure represents right atrial filling pressure and volume status. It is measured using a CVP line typically placed in the superior vena cava via the internal jugular route. A fluid challenge can be used to assess response, with a prolonged rise in CVP indicating adequate intravascular volume.
What is the purpose of a Swan-Ganz catheter in circulatory support?
A Swan-Ganz catheter, traditionally inserted to monitor cardiac output, provides information on left ventricular preload, pulmonary artery occlusion pressure, left atrial pressure, stroke volume, systemic vascular resistance, pulmonary artery resistance, and oxygen delivery and consumption.
When would vasoactive drugs be considered in circulatory support?
Vasoactive drugs may be considered in patients with ongoing circulatory compromise despite adequate circulating volume. These drugs are typically administered via the central venous route.
What are some commonly used inotropes in circulatory support and their effects?
Commonly used inotropes include noradrenaline (α agonist with vasopressor action), adrenaline (α and β receptor agonist that increases cardiac output and peripheral vascular resistance), dopamine (β1 agonist that increases contractility and heart rate), dobutamine (β1 and β2 agonist that increases cardiac output and decreases systemic vascular resistance), and milrinone (phosphodiesterase inhibitor that improves muscular contractility and acts as a vasodilator).
What does the pulmonary artery occlusion pressure (PAOP) measure?
The pulmonary artery occlusion pressure is an indirect measure of the left atrial pressure and the filling pressure of the left heart.
How is the most accurate trace of the pulmonary artery occlusion pressure obtained?
The most accurate trace is obtained by inflating the balloon at the tip of the catheter and occluding the vessel.
What is the significance of the pulmonary artery end diastolic pressure measurement?
If it is not possible to occlude the vessel, the measurement obtained will be the pulmonary artery end diastolic pressure.
How is the pulmonary artery occlusion pressure interpreted?
A normal pulmonary artery occlusion pressure is 8-12 mmHg. A low pressure (<5 mmHg) indicates hypovolemia, while a low pressure with pulmonary edema indicates ARDS. A high pressure (>18 mmHg) suggests overload.
What additional measurements can help accurately classify patients when combined with the pulmonary artery occlusion pressure?
When combined with measurements of systemic vascular resistance and cardiac output, it is possible to accurately classify patients.