airway management, ventilation, oxygen...

OXYGEN THERAPY AND AIRWAY

MANAGEMENT, VENTILATOR

THERAPY

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Dr.Dhaher JS Al-habbo

FRCP London UK

Assistant Professor in Medicine

DEPARTMENT OF MEDICINE

OXYGEN CONTENT OF BLOOD The theoretical maximum oxygen carrying capacity is

1.39 ml O2/g Hb, but direct measurement gives a

capacity of 1.34 ml O2/g Hb.1.34 is also known as

Hüfner’s constant.

The oxygen content of blood is the volume of oxygen

carried in each 100 ml blood.

It is calculated by: (O2 carried by Hb) + (O2 in

solution) = (1.34 x Hb x SpO2 x 0.01) + (0.023 x

PaO2)

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OXYGEN DISSOCIATION CURVE (ODC)

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Myocardial infarction

Acute pulmonary

disorders

Sepsis

Drug overdose

Liver failure

Head trauma

CHF

Hypovolemic shock

Blunt chest trauma

Acute neuromuscular disease

Acute abdomen (splinting)

Acute pancreatitis

Spinal cord injury

CLINICAL CONDITIONS WITH INCREASED

RISK OF HYPOXIA

Tachypnea

Cyanosis

Restlessness

Disorientation

Cardiac arrhythmias

Slow bounding pulse

Tachycardia

Hypertension

Dyspnea

Coma

Labored breathing (use of accessory muscles, nasal flaring)

Lethargy

Tremors/seizure activity

INDICATIONS FOR OXYGEN THERAPY

OXYGEN THERAPY

“Generally speaking”, a patient who is

breathing less than 12 and more than 24

/minute needs oxygen of some kind

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OXYGEN THERAPY TO ENSURE SAFE AND

EFFECTIVE TREATMENT

Oxygen is required for the functioning and

survival of all body tissues and deprivation for

more than a few minutes is fatal.

In immediately life threatening situations oxygen

should be administered.

Hypoxaemia. Acute hypotension.

Breathing inadequacy. Trauma. Acute illness. CO

poisoning. Severe anaemia. During the peri-

operative period.

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OXYGEN THERAPY TO ENSURE SAFE AND

EFFECTIVE TREATMENT

Oxygen is a prescription drug.

Prescriptions should include – Flow rate.

Delivery system.

Duration.

Instructions for monitoring.

Monitoring resps oxygen sats not definitive tool

need to be looking at other things acccessory

muscles etc

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OXYGEN THERAPY

Oxygen therapy Humidification Is recommended

if more than 4 litres/min is delivered.

Helps prevent drying of mucous membranes.

Helps prevent the formation of tenacious

sputum.

Oxygen concentrations will be affected with all

delivery systems if not fitted correctly or tubing

becomes kinked and ports obstructed.

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METHODS OF OXYGEN DELIVERY

Most common methods of oxygen delivery

include

Nasal Cannula

Venturi Mask

100% Non-Rebreather Mask

Mechanical Ventilation

HYPERBARIC OXYGEN THERAPY

(HBOT)

Nasal Cannula

Comfortable, convenient, mouth breathing will not effect % of O2 delivered

Liters/min = %

2 l/m = 24-28%

3 l/m = 28-30%

4 l/m = 32-36%

5 l/m = 36-40%

6 l/m = 40-44%

Cannot administer > 6 liters/minute (44%)

OXYGEN DELIVERY METHODS

NASAL CANNULA

Provides limited oxygen concentration

Used when patients cannot tolerate mask

Prongs and other uses

Concentration of 24 to 44%

Flow rate set between 1 to 6 liters

For every liter per minute of flow delivered, the

oxygen concentration the patient inhales increases

by 4%

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OXYGEN THERAPY Simple facemask Easy to use.

Allows administration of variable concentration dependant on

flow of fresh gas up to 40%.

Nasal cannulae Easy to use. Well tolerated. Comfortable for long

periods. Patient can eat and talk easily.

Possible to deliver oxygen concentrations of 24-40% at flow rates

of 1-6 litres/min.

Flow rates in excess of 4 litres/min might cause discomfort

and drying of mucous membranes and are best avoided.

Flow Rate: 10 L/Min

O2 Conc.: 40 – 60 %

Use: moderate FiO2, mouth breathers

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VENTURI MASK

Mostly used in the

hospital setting for

COPD patients

Concerns

Tight seal is a must

Interferes with

eating/drinking

Condensation

collection

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FiO2 Delivery

Blue 24% Yellow 28%

White 31% Green

35%

Pink 40%

Provides precise

concentrations of oxygen

Entrainment valve to adjust

oxygen delivery

VENTURI MASK

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Red 40% 10/L/M Blue 24% 2/L/M Yellow 35% 8/L/M

White28% 4/L/M Green 60% 15/L/M

Orange 31% 6/L/M

Delivery percentages

6 l/min = 55 – 60 %

8 l/min = 60 – 80 %

10 l/min = 80 – 90 %

>12 l/min = 90 + %

Benefit:

Has a one way expiratory

valve that prevents re-

breathing expired gases

Concern

May lead to O2 toxicity


100% NON-REBREATHER

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100% NON-REBREATHER MASK partial rebreather Mask

OXYGEN THERAPY

Non-rebreathing mask Allows the delivery of high

concentrations of oxygen (85% at 15

litres/min).

Has a reservoir bag to entrain oxygen. One way

valves prevent room and expired air from

diluting the oxygen concentration. A tight seal

is essential.

Reservoir bag must be seen to expand freely.

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MECHANICAL VENTILATION

Allows administration of 100% oxygen

Controls breathing pattern for patients who are unable to maintain adequate ventilation

Is a temporary support that “buys time” for correcting the primary pathologic process

INDICATIONS FOR MECHANICAL

VENTILATION Mechanical Failure

Ventilatory Failure

Oxygenation Failure

General Anesthesia

Post-Cardiac Arrest


Two categories of ventilators

Negative pressure ventilators Iron lung

Cuirass ventilator

Positive pressure ventilators Two categories

Volume-cycled (volume-preset)

Pressure-cycled (pressure-preset)

Iron Lung

MECHANICAL VENTILATION PEEP

Description Maintains a preset positive airway pressure at the end of expiration

Increases PaO2 so that FiO2 can be decreased

Increases DO2 (amt of delivered O2 to tissue)

Maximizes pulmonary compliance

Minimized pulmonary shunting

Indications PaO2 < 60 on FiO2 > 60% by recruiting dysfunctional alveoli

Increases intrapulmonary pressure after cardiac surgery to decrease intrathoracic bleeding (research does not support this idea)

MECHANICAL VENTILATION PEEP

Advantages Improves PaO2 and SaO2 while allowing FiO2 to be

decreased Decreases the work of breathing Keeps airways from closing at end expiration (esp. in pts

with surfactant deficiency)

Disadvantages Increased functional residual capacity (increases risk for

barotrauma) Can cause increased dead space and increased ICP In pts with increased ICP, must assure CO2 elimination Contraindicated: hypovolemia, drug induced low cardiac

output, unilateral lung disease, COPD

MECHANICAL VENTILATION CPAP

Description

Constant positive pressure is applied throughout

the respiratory cycle to keep alveoli open

Indications

To wean without having to remove the ventilator

and having to connect to additional equipment

MECHANICAL VENTILATION CPAP

Advantages

Takes advantage of the ventilator alarm systems

providing psychological security of the ventilator being

there

Disadvantages

Patient may sense resistance as he breathes through the

ventilator tubing

Respiratory arrest from disconnection

Respiratory infection (VAP)

Acid-base imbalances

Oxygen toxicity

Pneumothorax

GI bleeding

Barotrauma

Decreased cardiac output


COMPLICATIONS

VENTILATOR WEANING

Vital Capacity at least 10 – 15 ml/kg

Tidal Volume > 5 ml/kg

Resting minute volume > 10 L per minute

ABG’s adequate on < 40% FiO2

Stable vital signs

Intact airway protective reflexes (strong cough)

Absence of dyspnea, neuromuscular fatigue, pain, diaphoresis, restlessness, use of accessory muscles


(HBOT)

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(HBOT) Hyperbaric Oxygen Therapy

Uses a special chamber, sometimes called a pressure chamber, to allow a person to get high levels of oxygen in the blood.

This means that the air inside the pressurized chamber is typically 2 1/2 times greater than normal atmospheric pressure.

This leads to make the blood carrying larger amounts of oxygen, and bringing this oxygen to organs and tissues in the body.

By doing so, wounds, particularly infected wounds, can heal more readily.

HBOT— WHAT IS IT USED FOR?

Decompression sickness

Arterial gas embolism

Carbon monoxide

poisoning

Osteomyelitis

Skin grafts

Burns

Necrotizing fascitis

Anemia

Gas gangrene

Chronic non-healing wounds

Sports injuries

and more…

Analysis Arterial Blood Gas results:

If you can remember the following pyramid points and

steps, you will be able to analyze any blood gas report.

Pyramid points: In acidosis, the PH is down.

In alkalosis, the PH is high.

The respiratory function indicator is the PCO2.

The metabolic function indicator is the HCO3.

Normal blood gas value: PH: 7.35-7.45

PCO2: 35-45 mmHg

HCO3: 22-27meq/liter

PO2 : 80-100

Analysis Arterial Blood Gas results

Pyramid steps:

Pyramid step 1:- look at the blood gas report. Look at the PH, is it up or

down; if it is up; it reflects alkalosis. If it is down; it reflects

acidosis.

Pyramid step 2:- look at the PCO2, is it up or down; if it reflects an

opposite response to the PH, then you know that the

condition is a respiratory imbalance.


If it does not reflect an opposite response to the PH; then move on

to pyramid step 3.

Pyramid step 3:- look at the HCO3. Does the HCO3 reflect a corresponding

response with the PH; if it does, then the condition is a metabolic

imbalance.

Pyramid step 4:-

Remember, compensation has occurred if the PH is in a normal

range of 7.35-7.45. If the PH is not within normal range, look at

the respiratory or metabolic function indicators.


Respiratory Imbalances :

if the condition is a respiratory imbalance look at the HCO3

to determine the state of compensation.

if the HCO3 is normal, then the condition is uncompensated.

if the HCO3 is abnormal, then the condition is partial

compensation.


Metabolic Imbalance :

If the condition is metabolic imbalance, look at the PCO2

to determine the state of compensation.

If the PCO2 is normal, then the condition is

uncompensated.

If the PCO2 is abnormal, then the is partial compensation.


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