Ch. 16 Extrapulmonary Effects of Mechanical Ventilation

Flashcards about the extrapulmonary effects of mechanical ventilation

Name five areas of bodily function that can be affected by mechanical ventilation

Cardiovascular, pulmonary, neurological, renal, and gastrointestinal function

What are two factors that determine the extrapulmonary effects of mechanical ventilation?

The amount of pressure applied to the airways, and the patient’s cardiopulmonary status.

What happens to right ventricular preload during spontaneous inspiration?

Right ventricular preload is increased.

What happens to left ventricular preload during passive expiration?

It is decreased due to decreased venous return.

What two conditions can exacerbate the effects of positive pressure on cardiac output?

High positive pressure (>15 cm H2O) and volume depletion.

What are the possible results of the sympathetic response due to PPV?

An increase in sympathetic tone, systemic vascular resistance, and peripheral venous pressure, and peripheral shunting of blood away from the kidneys and lower extremities.

At what level of positive pressure should the respiratory therapist measure the blood pressure?

15 cm H2O

How can PPV improve stroke volume?

Venous return and thus preload to the heart is reduced, improving length-tension relationships and stroke volume.

What is the formula for calculating mean airway pressure?

½[PIP × (TI/TCT)]

What can high inspiratory flow rates cause?

Uneven ventilation.

What can a reverse I:E ratio do?

Significant increases in air trapping and hemodynamic complications.

What should a longer expiratory time be dependent on?

The severity of a patient’s lung disease.

What ventilator settings can be adjusted to affect hemodynamics?

Inspiratory flow and pattern, I:E ratio, inflation hold, PEEP, and ventilator mode.

Under what conditions will PEEP affect cardiac output?

It must transmit its pressure to the intrathoracic space and vessels to affect cardiac output.

What is the formula for calculating cerebral perfusion pressure (CPP)?

MABP – ICP

What is a clinical sign of increased ICP?

Jugular vein distention.

How does hyperventilation lower PaCO2?

It temporarily constricts cerebral vessels.

Name three humoral responses that occur with PPV.

Antidiuretic hormone (ADH), atrial natriuretic factor, and renin-angiotensin-aldosterone changes.

Which hormone's release is precipitated by blood pressure changes caused by PPV, resulting in oliguria?

Antidiuretic hormone.

What can result from the swallowing of air that leaks around the endotracheal tube cuff during PPV?

Gastric distention.

Why are seriously ill patients at risk for malnutrition?

Inadequate food intake and an increased metabolic rate.

How can complications be reduced?

Early recognition of the signs and symptoms of problems associated with PPV.