NEWS2 and COVID

Question 1

How does COVID affect patients?

Answer 1

Range of symptoms - generally mild e.g. cough, fever, shortness of breath

May progress to a viral pneunomia and ultimately acute respiratory distress syndrome (ARDS)

Question 2

How can respiratory failure be divided into 2 categories?

Answer 2

Type 1. Lung failure - gas exchange failure manifested by hypoxaemia

Type 2. Pump failure - ventilatory failure manifested by hypercapnia (abnormally elevated CO2 levels in the blood)

Question 3

Considering the mechanism of COVID lung injury, assuming the person can physically ventilate as normal, which part of the lung function is affected?

Answer 3

Gas exchange

Question 4

Isolated gas-exchange problems tend to initially show up as hypoxia, rather than hypercapnia. Type I respiratory failure is an oxygenation problem and type II respiratory failure is a ventilation problem. What type of respiratory failure do you think is more common, at least in the initial stages of COVID lung injury?

Answer 4

Type I

Question 5

If someone has a gas-exchange problem, they will work harder to breathe/ventilate to compensate. If this continues too long, their respiratory muscles will eventually fatigue. The partial pressure of carbon dioxide in the blood is inversely proportional to ventilation per unit time.

What will happen to the person’s partial pressure of carbon dioxide if the respiratory muscles fatigue?

Answer 5

Increase

Question 6

What type of respiratory failure occurs when the respiratory muscles are fatiguing?

Answer 6

Type II - ventilation

Question 7

For what type of respiratory failure do you think oxygen without ventilation support is generally more appropriate?

Answer 7

Type I

Question 8

For what type of respiratory failure do you think ventilation support (likely with oxygen too) is generally more appropriate?

Answer 8

Type II

Question 9

Why may, for diseases like COVID, ventilation be required even for Type I respiratory failure?

Answer 9

Gas exchange failure may be so severe that no amount of supplemental oxygenation can adequately compensate e.g. due to reduced lung compliance and alveoli collapse

Ventilation = increased pressures to keep alveoli open

Question 10

According to the WHO, what differentiates moderate from severe COVID other than parameters which would show up in the NEWS2 score?

Answer 10

Respiratory Distress

Question 11

Let PaO2 = the partial pressure of oxygen in the blood in mmHg (typically around 80 mmHg in health).

Let FiO2 = the fraction of oxygen in the air/oxygen mix inspired by the patient (0.21 in room air).

Which of these ratios could give a measure of how well the patient is oxygenating relative to the amount of oxygen they are receiving?

PaO2/FiO2
FiO2/PaO2
PaO2 - FiO2
PaO2 + FiO2

Answer 11

PaO2/FiO2

Question 12

What are some signs of respiratory distress?

Answer 12

High RR
Colour changes - cyanosis
Grunting during exhalation
Nose flaring
Retractions - chest appears to sink in deeper
Sweating
Wheezing
Leaning forward

Question 13

What is the first step for an acutely unwell patient?

Answer 13

ABCDE