Chapt 1 & 2 (RTH 162)

Question 1

What is the most common cause of increased airway resistance?

Answer 1

COPD. 
(Chronic obstructive pulmonary disease like emphysema
chronic bronchitis 
chronic asthma and 
bronchiectasis)

Question 2

What is one of the most frequent use of mechanical ventilation?

Answer 2

Management of postoperative patients recovering from anesthesia and medications.

Question 3

Explain the Poiseuille’s law:

Answer 3

The work of breathing increases by a factor of 16 fold when the radius of the airway is reduced by half its original size.

Question 4

What is the normal airway resistance in healthy adults?

Answer 4

Between 0.5 and 2.5 cm H2O/liter/second

Question 5

Airway resistance :

Answer 5

Airway resistance varies directly with the length and inversely with the diameter of the airway or ET tube.

Question 6

What is the equation of airway resistance, how is it calculated?

Answer 6

Pressure change / flow

Airway resistance and flow in the equation are inversely related.

Question 7

What is the equation for pressure change?

Answer 7

Peak inspiratory pressure - plateau pressure.

Question 8

When does ventilatory failure occur?

Answer 8

When the patients minute ventilation cannot keep up with CO2 production.

Question 9

In the pressure/volume loop what does an increase bowing of the pressure/volume loop suggest?

Answer 9

And overall increase in airflow resistance.

Question 10

What is lung compliance?

Answer 10

Volume change (lung expansion) per unit pressure change (work of breathing)

C= volume change / pressure change

Question 11

What is the equation for static compliance?

Answer 11

Corrected tidal volume / (plateau pressure - peep)

Question 12

What is the equation for dynamic compliance?

Answer 12

Corrected tidal volume / (peak inspiratory pressure - Peep)

Question 13

What is a normal static compliance?

Answer 13

40 to 60 cm H2O

Question 14

What is normal dynamic compliance?

Answer 14

30 to 40 cm H2O

Question 15

In the pressure to volume slope what does a shift of the slope towards the pressure axis indicate?

Answer 15

A decrease in compliance.

Question 16

In the pressure to volume slope what does a shift towards the volume axis indicate

Answer 16

An increase in compliance.

Question 17

What is the critical percentage of shunting from one side of the heart to the other where it will require a mechanical ventilation?

Answer 17

Shunting of 15% or more blood will require a mechanical ventilation.

Question 18

White is hypoxia?

Answer 18

Decrease of oxygen in the organs and tissue.

Question 19

What is hypoxemia?

Answer 19

Reduced oxygen in the blood.

Question 20

Why could we have oxygen failure without CO2 failure?

Answer 20

CO2 diffuses through capillary beds 20 times faster than O2.

Question 21

What is the action of positive pressure ventilation on the intrathoracic pressure?

Answer 21

PPV causes an increase in intrathoracic pressure and compression of the pulmonary blood vessels.
And a decrease in ventricular output, stroke volume and pressure readings.

Question 22

What is oliguria?

Answer 22

Urine output

less than 400 mL in 24 hours or less than 160 mL in eight hours.

Question 23

What is the caloric cost of breathing for COPD patients?

Answer 23

About 10 times that of normal individuals

Normal = 38 to 72 cal per day COPD = 430 to 720 cal/Day

Question 24

What will a sustained hyperventilation of less than 24 hours cause?

Answer 24

Respiratory alkalosis
Reduced cerebral blood flow
Intracranial pressure

Question 25

What could be some causes of changes in patient's mental status?

Answer 25

Hypoxia Hypercapnia Acidosis

Question 26

What is one of the strategies to reduce airflow resistance?

Answer 26

During mechanical ventilation remove the secretion in the endotracheal tube.

Question 27

What do patients with COPD or chronic airway obstruction typically do to compensate or accommodate for the airflow resistance?

Answer 27

Use a breathing pattern that is deep and slow.

Question 28

On the pressure/volume loop what does an increase in Boeing of the inspiratory limb suggest?

Answer 28

In excessive inspiratory flow.

Question 29

What is the target and the variable in a pressure-controlled ventilation?

Answer 29

During pressure-controlled ventilation the pressure is preset and the volume delivered by the vent is a variable.

Question 30

In a volume -controlled ventilation which is preset and which one is the variable?

Answer 30

During volume-controlled ventilation the volume is preset and the pressure generated by the ventilator is variable.

Question 31

In addition to elimination of waste, what what do kidneys do?

Answer 31

Regulation of drug clearance fluid and electrolyte balance acid-base balance

Question 32

What could PPV cause in the kidneys?

Answer 32

During positive pressure ventilation, hypoperfusion of the kidneys may decrease the rate of drug clearance leading to a higher drug concentration in the circulation.

Question 33

Explain the action of peep on the liver.

Answer 33

The liver is perfused by about 15% of the total cardiac output, and this perfusion rate may be reduced when peep is added to positive pressure ventilation.

Question 34

What is a nutritional consideration when it comes to PPV?

Answer 34

Nutritional balance is vital in the management of critically ill patients because, MALNUTRITION may cause MUSCLE FATIGUE, where as excessive nutritional support may cause excessive CO2 production.

Question 35

Renal perfusion and PPV:

Answer 35

Blood flow to the kidneys is decreased when blood volume of cardiac output is low. When renal perfusion or perfusion to the glomeruli of the kidneys is decreased, filtration becomes less efficient. Subsequently, the urine output is decreased, as the kidneys try to correct the hypovolemic condition by retaining fluid.

Question 36

Hey Patrick or liver considerations with PPV and peep.

Answer 36

Hepatic perfusion accounts for about 15% of the total cardiac output. PPV alone does not alter the blood flow to the liver. When peep is added to mechanical ventilation, the blood flow to the liver is noticeably reduced.

Question 37

What are the indicators of liver dysfunction?

Answer 37

Impairment of liver function is likely when coagulation time is increased. Prothrombin time >4 seconds Bilirubin level is increased >50 mg/L Albumin level is decreased <20 g/L

Question 38

TPN (total parenteral nutrition):

Answer 38

A fat based TPN should be considered for patients with significant or persistent CO2 retention, as fat emulsion may provide maximum caloric intake with minimum CO2 production.

Question 39

What happens if hyperventilation is retained after 24 hours?

Answer 39

- Leftward shift of Oxyhemoglobin curve - increased 02 affinity for hemoglobin - reduced or two release to tissues - cerebral tissue hypoxia - neurologic dysfunction - Hypophosphatemia

Question 40

What are the components of mean arterial pressure?

Answer 40

- Inspiratory time - respiratory frequency - peak inspiratory pressure - peep

Question 41

What is ventilatory failure?

Answer 41

Failure of the respiratory system to remove CO2 from the body resulting in an abnormally high PaCO2.