Oxygen and Suctioning Flashcards
what percent of atmospheric gas is contained in oxygen?
21%
What is hypoxia?
Inadequate oxygen supply at the tissue/cellular level
what is hypoxemia?
Abnormally low levels of oxygen in the blood
How long can the brain function without adequate supply oxygen?
6 minutes
which organs are most sensitive to hypoxia?
Liver, heart and lungs
Oxygen is a drug, True or false?
True
What is involved in an oxygen prescription?
The physician determines the amount of oxygen that the patient needs, and the type of delivery device needed.
What is partial pressure?
- Partial pressure is a way of assessing the number of molecules of a particular gas in a mixture of gases.
- It is the amount of pressure a particular gas contributes to the total pressure
What happens when there is an excessive build up of carbon dioxide in the bloodstream?
the pH of the blood changes, often with dire physiologic affects
What is oxygen tension?
The amount of oxygen in air or arterial blood is called the oxygen tension (partial pressure) and is written as PaO2
What is hypoventilation?
poor expelling of CO2
What is hypercapnia?
increase in partial pressure of CO2
Respiratory acidosis?
- Inadequate ventilation by the lungs (hypoventilation) result in poor expelling of CO2.
- As a result, PaCO2 increases (hypercapnia).
- The increase inPaCO2in turn decreases the HCO3−/PaCO2ratio and decreases pH.
metabolic acidosis?
- Metabolic acidosisis a serious electrolyte disorder characterized by an imbalance in the body’s acid-base balance.
- This can be the result of drop in bicarbonate and cause respiratory acidosis.
What are arterial blood gases (ABG)?
The effectiveness of pulmonary function is most accurately measured by laboratory testing of arterial blood for the concentration of oxygen, carbon dioxide, HCO3-, acidity and the saturation of hemoglobin with oxygen (SaO2).
Normal ABG values
When PaO2 is below 60mm Hg or the hemoglobin saturation is below 90%, it can be assumed that the adequate oxygenation of blood is not taking place.
What is the fraction of inspired oxygen?
- Volumetric fraction of oxygen in inhaled air.
- Patients who have trouble breathing are provided with oxygen-enriched air, which means a higher-than-atmosphericFiO2.
Lab values for ABG
pH: 7.35 – 7.45
PaCO2: 35 – 45mm Hg
PaO2: 75 – 100mm Hg
HCO3-: 22 – 30 mmol/L
SaO2: 95 - 100%
What level is FiO2 typically maintained at?
below 0.5 even with mechanical ventilation to avoid oxygen toxicity
PaO2 to FiO2 ratio
- The ratio ofpartial pressure arterial oxygen and fraction of inspired oxygen, is a comparison between the oxygen level in the blood and the oxygen concentration that is breathed.
- This helps to determine the degree of any problems with how the lungs transfer oxygen to the blood.
what is known as theHorowitz indexorCarrico index?
The ratio ofpartial pressure arterial oxygen and fraction of inspired oxygen
normal breaths per minute for an adult?
15-20
Normal number of breaths per minute in a child (1-10 years)?
20-30
Normal number of breaths per minute in an infant (>1 year)?
30-60
What is pulse oximetry?
- Pulse oximeter is used to monitor the oxygen saturation of hemoglobin.
- Fast, non-invasive method of monitoring the patient for sudden changes in oxygen saturation, such as when a patient has just been removed from a ventilator.
how does a pulse oximeter work?
- Sensor is attached to the fingertip or ear lobe.
- A photodetector attached to the sensor can distinguish between oxygenated and deoxygenated hemoglobin in blood pulsing through the tissue at the location of the sensor.
Where is an ABG usually retrieved from?
- Radial artery at the wrist (common)
- Brachial artery
- Femoral artery at the groin
Who needs oxygen therapy?
Any patient with impaired O2 uptake:
- Trauma
- Shock
- Sleep apnea
- Acute anxiety with increased heart rate and shortness of breath (SOB)
what are diseases/illnesses that cause a patient to require oxygen therapy?
- Emphysema
- COPD (Chronic obstructive pulmonary disease)
- Pneumonia
- Asthma
- Lung tumours
In hospitals how is oxygen mostly utilized?
oxygen piped into patient rooms, emergency suites and diagnostic imaging departments
- wall outlets make it readily available
what is a flow meter?
- A flow meter is attached to each wall outlet to regulate flow.
- Flow rate of oxygen is measured in litres per minute (LPM).
- Flow rates – 0 – 15LPM
When reading a ball float flowmeter, which part of the ball do you use to read?
read from the middle of the ball
what is portable oxygen delivery?
- If oxygen is not piped in through wall outlets, it is available compressed and dispensed in tanks of varying sizes.
- A large, full tank contains 2000lb of pressure per square inch.
What are the 2 regulator valves on portable oxygen delivery?
one indicates how much oxygen is in the tank, the other measures the rate of flow through the delivery tubing
What meters do the regulators of the portable oxygen delivery have?
a flowmeter and pressure manometer
what is the universal colour for oxygen?
green
What cylinders must be used during MRI studies?
aluminum cylinders
What are low flow delivery systems?
- A low or variable-oxygen concentration device does not meet the entire inspiratory needs of the patient.
- An unknown amount of room air is entrained through the nose or mouth and mixes with the constant amount of 100% oxygen administered.
What are high flow delivery systems?
- A high flow device aka fixed or precise oxygen concentration device, does meet the inspiratory needs of the patient when the device is functioning properly.
- The inspired concentration of oxygen does not change with the altered breathing patterns.
- Room air gases are precisely mixed with 100% oxygen before reaching the patient.
- The constant ratios used in the mixing of gases (oxygen and room air) will provide the patient a precise oxygen percentage or FiO2, regardless of the breathing pattern
What is the nasal cannula?
- Cannula is held in place by looping the tube over the patient’s ears.
- Used in patients that do not require rigid control of respiration. Breathing range and depth is even.
- Well tolerated by patients as it does not interfere with talking, eating or sleeping.
is the nasal cannula a high flow or low flow device?
low flow
what rates of oxygen are provided through a nasal cannula?
- Oxygen flow rates of 1 – 4LPM are delivered, with concentration of oxygen ranges from 21 - 60%.
- Much lower rates for children (1/4 - 1/2LPM).
what is epitaxis?
nose bleed
nasal cannula and humidity?
- Higher rates will result in the drying of the nasal mucosa (and epistaxis) because of the position of the tube against the skin of the nostrils.
- Therefore, humidity is added to the nasal cannula delivery system when flows greater than 4LPM (up to 6LPM) are used.
When should you turn on a nasal cannula?
- Oxygen should be turned on and flowing at the desired rate before placing any low flow device on a patient.
- This prevents a sudden burst of oxygen into the patient’s nostrils when the regulator is first turned on.
cons for masks for oxygen delivery
- Not as well tolerated as nasal cannula.
- Can be hot because they are made of plastic and can stick to patient’s face.
- Need to be removed for eating.
- Can muffle speech
- Head straps may not fit well, and therefore, masks often become dislodges during sleep.
- Increase risk of aspiration if patient vomits.
why use oxygen masks?
They deliver accurate as well as high concentrations of oxygen.
What are simple face masks?
- Short term oxygen therapy
- Attached to oxygen supply and flow meter or oxygen tank
- Covers patient’s nose and mouth
- Because the mask does not fit tightly over the face, the concentration of oxygen delivered varies from 30 – 50%.
- No less than 5LPM (5-10LPM).
- Needed to flush the CO2 from within the mask when the patient exhales.
What is a non-rebreather mask?
- High flow system
- Reservoir bag fills with oxygen to provide constant supply.
- Valves prevent rebreathing of exhaled (prevents dilution)
- 15 LPM.
- Able to deliver higher concentrations of oxygen.
- If correctly used, may supply 100%, but close to 60 – 80% oxygen concentration
What is a partial rebreather mask?
- Delivers 60 – 90% oxygen concentration.
- 5 – 15 LPM.
- The rebreather mask has a 2-way valve between the mask and the bag therefore, the bag collects some of the exhaled air.
How does a partial rebreather mask work?
- Allows the first 1/3rd of the exhaled breath (which has a higher O2 concentration) to get into the reservoir bag.
- Patient rebreathing air held in dead air space in the trachea, therefore, uses less oxygen.
- Exhaled air flows into the reservoir bag and allows the patient to breathe a mixture of oxygen and carbon dioxide.
- When carbon dioxide enters the lungs, it stimulates breathing.
What is a nebulizer?
- Adrug delivery device used to administer medication in the form of a mist inhaled into the lungs.
- High flow device, precise oxygen concentrations (28 – 100%). At least 8LPM.
- Can be used with aerosol face masks, ETTs or tracheostomies
- Uses oxygen to break up solutions (of medication) and suspends it into small aerosol droplets that can be directly inhaled by the patient.
- Rx of cystic fibrosis, asthma, COPD etc.
What is a Venturi mask?
- air-entertainment mask
- limits oxygen to 24-60% by mixing room air and the oxygen in specific percentages
- delivers known oxygen concentration to patients on controlled oxygen therapy
Oxygen Tent/hood
- consists of a canopy placed over the head and shoulders, or over the entire body of a patient to provide oxygen at a higher than normal volume
- used when higher rate of humidity and concentration of O2 required is higher than present in the natural environment
where do you most commonly see oxygen tents/hoods
often seen in paediatrics - rarely adults
can you use an oxygen tent/hood with x-rays or electrical devices?
no
what is a transtracheal delivery system?
- for persons who require continuous therapy for long periods
- mechanical ventilator/respirator use
- controlled or partially controlled inspiration, expiration and FiO2
- radiographer most often encounters these patients during mobile radiography
- ET tube or tracheostomy tube
When is tracheostomy opted over the use of an ET tube?
if it needs to be used too long term
What are home oxygen delivery systems?
- Patients often use portable oxygen that may be delivered as compressed gas or liquid.
- Compressed oxygen come in tanks: smaller than hospital tanks but the system of delivery is similar.
- Liquid oxygen is liquefied gas that concentrates oxygen into a lightweight container the size of a thermos bottle. Conveniently portable and lasts longer than other forms of oxygen.
what are the hazards of oxygen administration?
- considered medication
- excessive oxygenation may produce toxic effects on the lungs and CNS or may depress ventilation
- Healthy patient can tolerate 50% FiO2 for 24-48 hours
Oxygen toxicity?
- may result from inhalation of high concentrations of oxygen
- Mild may result in reversible tracheobronchitis
- Severe may cause irreversible parenchymal lung injury
Risk of infection and bacteria in oxygen administration?
- Infection and bacteria thrive in oxygenated environments. Therefore, equipment used to deliver oxygen may be a potential source of infection
- Important to make sure tubing, cannula and masks for oxygen delivery are changed between patients
COPD
- Excessive oxygen may depress the respiratory drive and patient may stop breathing.
- Chronic lung disease results in chemoreceptors that no longer respond to CO2 stimulus.
- They may require some degree of hypoxemia as a respiratory stimulus.
- If they receive excessive oxygen, the hypoxia is no longer present and respiration ceases.
Oxygen delivery equipment for the imaging department?
- Oxygen Source: tank or in wall
- Sterile nasal cannula or simple face mask (packaged and unused). These are disposable items.
- Connecting tubing or an adapter to fit into a wall unit or tank.
- A humidifier, if indicated.
- A flow meter.
Suctioning?
- Patients who are unable to clear their throats or mouths of blood, secretions or vomit
- Prevent aspiration/pneumonia & respiratory arrest
suctioning units?
- Usually wall mounted units.
- Should be readily available.
- Discarded after each use and replaced immediately.
how is suctioning preformed?
- Performed through either oropharynx, nasopharynx or tracheostomy.
- By respiratory therapist, nurse or MD.
- Aseptic conditions used to prevent respiratory infections.
- In an emergency - not past larynx (unless specifically trained)
Contraindications to suctioning?
- Facial injuries – nasal deformity, occluded nasal passage
- Loose teeth, dentures, crowns
- Bleeding esophageal varices
- Recent nasal, oral or esophageal surgery
- Croup (laryngotracheobronchitis) – Swelling within trachea, severe bronchospasm, irritable airway
