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1. What are the three elements that must be present for an infection to spread?
- Three elements must be present for an infection to spread:
- 1. A source of pathogens
- 2. A susceptible host
- 3. A route of transmission
2. What are the three major routes for transmitting infection to the lungs?
- Three major routes:
- 1. Aspiration of oropharyngeal or gastric secretions
- 2. Inhalation of liquid aerosol droplets, droplet nuclei or dust
- 3. Blood-borne (hematogenous) infection spread from a distant site
3. What are the respiratory care equipment that is most likely to spread infection?
- Equipment most likely to spread pathogens
- 1. Large reservoir jet nebulizer
- 2. Ventilator circuits
- 3. Bag-valve-mask devices (manual resuscitators)
- 4. Oxygen therapy apparatus
- 5. Pulmonary function devices
- 6. Suction equipment
4. What is the single most important way to prevent the spread of infection?
5. What is the PPE, and which items you would use for the standard precautions and each of the isolation precautions?
- Standard- Gloves, gown, mask, and goggles
- Contact- Golves and gown
- Droplet- Gloves, gown, surgical mask
- Airborne- Gloves, gown, HEPA mask, goggles, or particulate respirator
6. What are the normal value for the partial pressure of oxygen and hemoglobin saturation, and the values that would demonstrate a documented hypoxemia (adults and neonates)?
- 1. Normal adult partial pressure of oxygen in arterial blood (PaO2) at sea level is 80 to
- 100 mmHg, saturation of oxygen in arterial blood (SaO2) of 97%
- 2. Documented hypoxemia is PaO2 less than 60 mmHg or SaO2 less than 90% breathing
- room air (FIO2 21%) or a PaO2 and/or a SaO2 below desirable range for specific clinical
- 3. In neonates, hypoxemia is a PaO2 less than 50 mmHg and/or a SaO2 less than 88% or
- capillary oxygen tension (PcO2) less than 40 mmHg.
7. What are the principles of operation for pulse oximetry?
A pulse oximeter combines the principles of spectrophotometry with photoplethysmography
8. What are the indications for pulse oximetry?
- 1. The need to quantitate the response of arterial oxyhemoglobin saturation to therapeutic
- intervention or to a diagnostic procedure.
2. The need to monitor the adequacy of arterial oxyhemoglobin saturation.
- 3. The need to comply with mandated regulations and recommendations by authoritative
9. What is a pulse oximetry reading value that is considered to be unreliable?
Most clinicians consider pulse oximetry readings unreliable at saturations of below 80%
10. What are the factors/limitations that affect the accuracy of pulse oximetry?
- Presence of HbCO
- Presence of high levels of metHb
- Presence of fetal hemoglobin
- Vascular dyes
- Elevated bilirubin
- Dark skin pigmentation
- Nail polish
- Ambient light
- Poor perfusion
- Motion artifact
11. Be able to calculate the ideal tidal volume to be delivered to a patient for IPPB therapy.
To Calculate Ideal Body Weight:
- Adult Male-106 + [ 6 (height in inches-60) ]
- Adult Female-105 + [ 5 (height in inches � 60) ]
Once IBW is obtained convert to Kg by dividing by 2.2
- Ex. A woman who is 5�3�� obtain IBW in Kg
- 105 + [ 5 (63-60)] = 120
- 120/2.2 = 54.5 may round if desired
- To obtain minimal accepted IPPB tidal volume:
- (for medication delivery)
10-15 mL/Kg of ideal body weight
- Ex. 5�3�� woman
- IBW in Kg = 54.5 or 55
- 55 X 10 = 550
- 55 X 15 = 825
- 30% of predicted Inspiratory Capacity
- Ex. 5�3�� woman
- IBW in Kg = 54.5 or 55
*Multiplying the IBW in Kg by 50 will give the predicted Inspiratory Capacity, you are looking for 30% of that volume.
55 X 50 X .30 = 825
- To obtain the Target Volume or Goal:
- (for hyperinflation)
- 75% of the predicted Inspiratory Capacity
- Ex. 5�3�� woman
- IBW in Kg = 54.5 or 55
*Multiplying the IBW in Kg by 50 will give the predicted Inspiratory Capacity, you are looking for 75% of that volume.
55 X 50 X .75 = 2063
12. The maximum liter flow that can be achieved with the air mix plunger in and out of the Bird Mk 7.
Peak flows of 80 L/min can be set by the flow rate control when the Venturi system (air mix plunger out) is used and about 50 L/min maximum when 100% source gas setting is used (air mix plunger in)
13. The function of the pneumatic expiratory timing device on the Bird Mk 7.
Operates using a timing cartridge, needle valve, and a timing arm. During inspiration the cartridge is pressurized with the gas source, and a spring opposite the inlet is compressed. When the operator opens the needle valve gas is allowed to leak from the cartridge into the pressure chamber. As the cartridge empties, the spring pushes the diaphragm to the right . The timing arm contacts the clutch plate and slides the ceramic switch to the open position beginning inspiration and the cycle is repeated.
- Is used to ventilate patients who are apneic, not used often. If operated during IPPB therapy it can cause asynchronous ventilation (when a patient breaths out and the machine delivers a breath.
- The needle valve regulates how fast the cartridge empties and therefore regulates the expiratory time and indirectly the respiratory rate
*By increasing the leak from the expiratory cartridge you will decrease the expiratory phase
14. The air mix control and its effect on FIO2 on the Bird Mk7.
- 1.When the air mix plunger is in the out position the FIO2 delivered is between 60 to 90 % (source gas 100% oxygen). The OUT position is considered to be air mix. The FIO2 and the flow of gas depend on the jet of the venturi, the entrainment of the venturi, and the source gas that goes to the nebulizer.
- 2. When the Air Mix control is in the IN position the FIO2 is 100% (source gas is 100% oxygen). During inspiration, on this setting, the venturi is bypassed and just source gas is fed through a bleed hole that sits at the back side of the plunger in the pressure chamber. The only other gas entering into the patients system comes from the nebulizer and is 100% source gas. This gives the following flow and pressure pattern for the delivered gases.
15. The controls that affect the inspiratory time and how.
- 1. Pressure control- if gas flows into a closed chamber at a constant rate it will take longer to reach a higher pressure than a low one
- 2. Flow rate- The closed chamber fills faster at a higher flow decreasing inspiratory time.
16. The controls that affect the tidal volume and how.
- One goal of IPPB is hyperinflation:
- 1. Pressure control- primary control, the higher the pressure the more gas is delivered before expiration
- 2. Flow rate- if the flow rate is high to the point of turbulent flow the pressure will build rapidly (lowers I-Time)
17. The differences and similarities of the Bird Mk7 and Mk 7A.
- Know the controls that are the same on both machines:
- Venturi, sensitivity selector, and pressure selector.
- Know the differences on the machines:
- The 7A has the apneustic flowtime control
- The 7 has an air mix control
18. The definition of IPPB.
- IPPB is a technique used to provide short-term or intermittent mechanical ventilation for the purpose of:
- augmenting lung expansion, delivering aerosol medication, or assisting ventilation.
19. The physiological effects of IPPB and their descriptions.
- 1. Positive intrathoracic pressure
- 2. Mechanical bronchodilation
- 3. Increased tidal volume
- 4. Decreased work of breathing
- 5. Decrease in PaCO2
- 6. Efficient ventilatory pattern
- 7. Removal of respiratory tract secretions
20. The adverse effects of IPPB and their descriptions.
- Adverse effects of Positive Pressure:
- 1. Pulmonary effects
- 2. Circulatory effects
- 1. Decreased venous return that leads to decreased cardiac output, hypotension and increased intracranial pressure
- 2. Physical and pharmacologic disturbance of the heart with arrhythmias and coronary insufficiency
- 3. Gastrointestinal effects
- 4. Effects on ABGs
- 5. Adverse effects of aerosols
- 6. General adverse effects
21. The contraindications for IPPB therapy.
1. Only absolute contraindication to IPPB is an untreated tension pneumothorax.
- 2. a. Intracranial pressure (ICP greater than 15 mmHg): IPPB can retard cerebral venous return and potentially increase intracranial pressure.
- b. Recent facial, oral, or skull surgery
- c. Hemodynamic instability (cardiovascular insufficiency: such as hypotension, hypovolemia, arrhythmias, coronary artery insufficiency).
- d. Tracheoesophageal fistula: IPPB can cause gastric insufflation and vomiting
- e. Recent esophageal surgery
- f. Active hemoptysis (pulmonary hemorrhage): massive active bleeding from pulmonary tissue is a medical emergency.
- g.Nausea: can lead to patient vomiting and aspiration
- h. Air swallowing: causing gastric insufflation
- i. Active untreated tuberculosis: IPPB may spread localized disease or potential to disrupt cavity lesions of advanced stages of untreated TB.
- j. Bullous lung disease (radiological evidence of bleb): IPPB should not be given if it results in evidence of air trapping, such as, dyspnea, feeling of hyperinflation, radiological changes, worsening of pulmonary function.
- k. Singulation (hiccups)
- l. Pulmonary air leak: can be persistent leak from an intubated pneumothorax or seen as subcutaneous emphysema.
- m. History of pneumothorax: spontaneous, or secondary to IPPB
- n. Recent lobectomy/pneumonectomy: may damage excision site and cause air leakage
- o. Subjective deterioration: if patient is unable to use IPPB correctly or if the treatment causes the patient distress
22. The indications for incentive spirometry.
- A. Any of the following diagnoses or conditions:
- 1. Atelectasis (sub-segmental, segmental, lobar or lung)
- a. Obesity
- b. Chest wall deformity
- c. Following upper abdominal or thoracic surgical procedures
- 2. Chronic obstructive lung disease (including asthma, emphysema, chronic bronchitis)
- a. Surgery in patient with COPD
- 3. Pneumonia
- 4. Bronchiectasis
- B. Reduced vital capacity, especially restrictive lung defect associated with quadriplegic and/or dysfunctional diaphragm
- C. Poor patient motivation to affect spontaneous deep breathing without a physical incentive
23. The contraindications for incentive spirometry.
- 1. Comatose patient
- 2. No patient cooperation
- 3. Patient unable to understand or demonstrate proper use of the device
- 4. Patient unable to deep breathe effectively (e.g., with vital capacity [VC] less than about 10 mL/kg or inspiratory capacity [IC] less than about one third of predicted)
24. The factors that are likely to lead to atelectasis.
- 1. Obesity
- 2. Neuromuscular disorders
- 3. Heavy sedation
- 4. Surgery near the diaphragm
- 5. Bed rest
- 6. Poor cough
- 7. History of lung disease
25. The modalities that IPV employs.
- IPV therapy is a combination of:
- Therapeutic aerosol (high density aerosol delivery to hydrate viscous mucous plugs)
- Volume oriented IPPB (positive end expiratory pressure to recruit alveolar lung units and assist in expiratory flow acceleration during a cough maneuver)
- Chest Physiotherapy (percussive oscillatory vibrations which loosen retained secretions)
26. The clinical outcomes associated with IPV therapy.
- Increased sputum production
- Improvement in breath sounds
- Improved lung and chest wall mechanics (compliance and resistance)
- Resolution of lung infiltrates and atelectasis as shown on chest x-ray
27. The uses for manual resuscitators.
- 1. CPR, both in and out of the hospital
- 2. Manual hyperinflation with high concentrations of O2; such as before and after suctioning.
- 3. During transport of critically ill patients.
- 4. Ventilator patients; any time they need to be off the ventilator such as during transport, medical procedures, ventilator tubing change, etc.
- 5. Stand-by for any procedure that may lead to respiratory arrest.
- 6. Coughing patients
28. How manual resuscitators are classified.
Manual resuscitators are generally classified by the type of nonrebreathing valve used. There are two main valves; a spring loaded mechanism and those relying on diaphragm valves. The diaphragm valves are further subdivided into duckbill or fishmouth and leaf type of valves.
29. The characteristics of non-self inflating (flow inflating) manual resuscitators.
- 1. Can deliver precise FIO2 (can guarantee 100% oxygen when used with oxygen source).
- 2. Can deliver a wide range of PEEP.
- 3. Can control peak inspiratory pressure.
- 1. Can deliver dangerously high pressures to a patient.
- 2. Not enough flow, patient will rebreathe their own gas.
- 3. Not enough flow, patient will not get adequate ventilatory volume
- Flow-inflating vs. self inflating manual resuscitators
- - Flow inflated bags have the disadvantage of always needing an adequate flow rate of gas to work
- - They have the advantage of being the easiest bag to feel changes inside the patient
- - Excessively high flow rates through the flow-inflated bags can raise the PEEP inadvertently
- - If the patient interface slips off the self-inflated bag, it will require a little time to re-inflate
- - The flow-inflated bag can deliver drugs
- - The self-inflated bag has less parts to malfunction or lose
30. The hazards of manual resuscitators.
- 1. Unrecognized equipment failure
- 2. Gastric distention with mask ventilation.
- 3. Pulmonary barotrauma/volutrauma
- These are the three most common problems when using self inflating manual resuscitations.
- Troubleshooting for these problems can prevent them from occurring.
31. The criteria an �acceptable� adult manual resuscitator should meet.
- The AARC Guidelines for manual resuscitator state that they must:
- 1. Have no pressure-relief valve for adults and children; infant devices must incorporate an in-line manometer.
- 2. Have a bag volume of approximately 1,600 ml for adults and children, and approximately 500 ml or less for infants.
- 3. Have minimal forward and back leak.
- 4. Have a standard patient valve connector of 15:22 mm (ID:OD).
- 5. Be impossible to misassemble.
- 6. Be easily sterilized or for single patient use.
- 7. Provide for measurement of exhaled tidal volume.
- 8. Be capable of providing an FDO2 of 1.0 even when large volumes are delivered.
- 9. Provide some indication that supplemental oxygen is being supplied (easily ascertained with bag reservoir but difficult with tube-type reservoir).
- 10. Be capable of being restored to proper function after being disabled with an obstruction (e.g. vomitus) within 20 sec.
- 11. Be able to be restored to proper function after being dropped from a height of 1 meter onto a concrete floor.
- 12. Be designed so that pressure generated at the patient connection port is less than 5 cm H2O during exhalation (at a flow of 5 L/min for patients weighing <10 kg and 50 L/min for all others).
- 13. Be designed so that pressure generated at the patient connection port does not exceed -5 cm H2O during inspiration (at a flow of 5 L/min for patients weighing <10 kg and 50 L/min for all others).
- 14. Be capable of providing a high FDO2 during spontaneous breathing with low inspiratory and expiratory resistance.
32. How to achieve high concentrations with manual resuscitators.
- When using a manual resuscitator we usually need high concentrations of oxygen (such as in CPR). We can increase the oxygen concentration delivered by a manual resuscitator unit in three ways:
- 1. Using the highest acceptable oxygen flow rate to the bag.
- 2. Adding a reservoir for oxygen collection.
- 3. Utilizing the longest possible bag refill time.
33. The various types of suctioning.
- 1. nasopharyngeal
- 2. nasotracheal
- 3. oropharyngeal
34. The hazards and complications of suctioning
- 1. Hypoxia/Hypoxemia
- Is the most common complication of suctioning.
- The complications listed below are from the AARC Clinical Guidelines:
- 1. Hypoxemia/Hypoxia
- 2. Cardiac dysrhythmias
- 3. Hypotension and Hypertension
- 4. Pulmonary atelectasis
- 5. Mucosal trauma
- 6. Contamination/Infection
- 7. Increased intracranial pressure
- 8. Bronchoconstriction/Bronchospasm
- 9. Laryngospasm, gagging/vomiting, and uncontrolled coughing
- 10. Cardiac arrest and death
35. The contraindications for suctioning.
- Most contraindications are relative to the patients risk of developing adverse reactions
- or worsening clinical conditions as the result of the procedure.
- 1. Patient doesn�t need airway suctioning.
- -Undue trauma can be done to the patient by suctioning without secretions. The negative pressure will adhere to the tracheal wall since there are no secretions.
- 2. Untrained personnel or improper equipment should not be used for airway suctioning on a patient.
- -They could cause the patient undue trauma and at worst cardiac arrest
- 3. An unstable cardiovascular status, especially with severe hypotension can cause the patient to go into cardiac arrest.
- -It would be best if the patient could be stabilized before suctioning, if needed.
- 4. Excessively high intercranial pressure should be lowered, if possible, before suctioning.
Make sure you know the following:
- 5. Upper airway complications/contraindications for nasotrachel suctioning include:
- -Occluded nasal passages
- -Nasal bleeding
- -Epiglottitis or Croup (this is an absolute contraindication) *******
- -Acute head, facial, or neck injury
- -Coagulopathy or bleeding disorder
- -Irritable airway
- -Upper respiratory tract infection
36. The proper positioning of the head during intubation.
- The head must be placed in the �sniffing� position,
- With the patient supine, place a pad under the patient�s head to flex the neck, and then extend the head by moving the chin up and back or pressing down on the forehead
37. The landmarks, in order of visualization, during intubation.
Tongue, uvula, glands, vallecula, epiglottis, arytenoids, vocal cords, glottis
38. The indications of oral tracheal intubation.
- 1. The relief of airway obstruction
- 2. The protection of the airway
- 3. The facilitation of tracheal suctioning
- 4. The facilitation of prolonged artificial ventilation or CPAP
- -According to the AARC Clinical Practice Guidelines The general conditions requiring airway management are impending or actual:
- 1. Airway compromise
- 2. respiratory failure (and to facilitate ventilation)
- 3. Need to protect the airway
39. The complications that can occur during intubation.
- Failure to establish a patent airway, to intubate the trachea, or recognize esophageal intubation
- Trauma to nose, mouth, tongue, pharynx, larynx, vocal cords, trachea, esophagus, spine, eyes, teeth
- Aspiration and/or infection (pneumonia, sinusitis, otitis media)
- ET tube problems (cuff, pilot balloons, kinking, occlusion, extubation)
- Autonomic or protective neural responses (hypo/hypertension, brady/tachycardia, dysrhythmias, laryngospasm, bronchospasm)
- Inadequate O2 delivery
- Hypoventilation or hyperventilation
- Gastric insufflation and/or rupture
- Reduced venous return
- Aspiration, vomiting
- Prolonged interruption of ventilation for intubation
- Movement of unstable cervical spine
40. The steps to follow immediately following oral endotracheal tube insertion.
- Step 8: Insert the Tube
- Once the tube is in place, stabilize the tube with one hand, using the other to remove the laryngoscope and the stylet.
- Be sure to note centimeter depth marking of the tube at the lip or teeth.
- At this time the cuff is inflated to MOV (minimal occluding volume).
- Immediately oxygenate and ventilate the patient.
41. How the straight (Miller) and curved (MacIntosh) blade work in relationship to the epiglottis.
- Step 7: displace the epiglottis
- The technique used to move the epiglottis depends on the type of blade used.
- The curved or MacIntosh blade lifts the epiglottis indirectly as the tip of the blade is advanced into the vallecula and the laryngoscope is lifted up and forward.
- The straight or Miller blade lifts the epiglottis directly as the tip of the blade is advanced beyond it and the laryngoscope is lifted up and forward.
42. The ideal position of the endotracheal tube above the carina.
2 to 5 cm (some references say 3 to 7) above carina, between the 2nd to 3rd intercostal space at the level of the aortic knob.
43. Extubation � the cuff leak test
It is a test designed to help predict the occurrence of glottic edema and/or stridor after extubation.
- Two ways to perform the same test:
- 1. For the spontaneously breathing patient, you totally deflate the tube cuff and then completely occlude the endotracheal tube.
- The presence of a peritubular leak during spontaneous breathing indicates no encroachment of the airway and a positive test. (This means that there is minimal risk for upper airway obstruction)
- A negative test is one where no peritubular leak is noted during breathing. This indicates a high potential for post extubation obstruction.
- 2. With positive-pressure ventilation, a peritubular leak is assessed during ventilation the same as with spontaneous ventilation.
44. The treatment of post extubation stridor.
If stridor due to glottic edema is noted a racemic epinephrine treatment may be needed.
- A cool aerosol is indicated post extubation to decrease swelling.
- NOTE: Heated mist may only increase swelling that normally occurs after extubation.
45. The weaning criteria for extubation.
- Weaning criteria
- 1. The capacity to maintain adequate arterial oxygenation
- 2. The capacity to maintain appropriate pH and pCO2 during spontaneous ventilation
- 3. Adequate respiratory muscle strenght
- 4. Maximum negative inspiratory pressure >30 cm H2O
- 5. Vital capacity >10 mL/kg ideal body weight
- 6. In adults, respiratory rate <35/min during spontaneous breathing
- 7. In adults, a rapid shallow breathing index of <98-130
- 8. Normal consciousness
- 9. Adequate airway protective reflexes
- 10. Easily managed secretions
46. The steps to perform prior to extubating a patient.
When removing the tube what do you need to do:
- 1. Suction oropharynx
- 2. Suction the endotracheal tube
- 3. Preoxygenate the patient
- Step 5: Suction the Endotracheal tube and pharynx to above the cuff.
- Step 6: Oxygenate the Patient after suctioning
- Step 7: Remove the tape or securing device.
- Step 8: Deflate the Cuff.
- Step 9: Remove the tube.
47. The ECG waveform and what each part of the waveform represents.
- P-Wave: represents atrial depolarization
- P-R Interval: represents the time it takes an impulse to travel from the atria through the AV node, bundle of His, and bundle branches to the Purkinje fibers.
- QRS Complex: represents ventricular depolarisation.
- T Wave: represents the repolarization of the ventricles.
- What is the hearts dominant pacemaker?
- SA node
48. The 4 hemodynamic pressures.
- CVP � central venous pressure
- MAP � mean arterial pressure
- PAP � pulmonary artery pressure
- PCWP � pulmonary capillary wedge pressure or PWP � pulmonary wedge pressure
49. What each hemodynamic pressure measurement represents and their normal values.
- CVP � indicates a right heart problem
- Normally measures 2-6 mmHg (4-12 cmH2O)
- The pressure of the blood in the right atrium or vena cava, where blood is returned to the heart from the venous system.
- Represents the end-diastolic pressure in the right ventricle (RVEDP)
- - reflects the right ventricular diastolic pressure or the ability of the right side of the heart to pump blood
- Reflects preload (filling volume) for the right ventricle.
- The CVP may also be referred to as:
- - Right atrial pressure
- - Right atrial filling pressure
- - Right side pre-load
- - Right ventricular filling pressure
- - Right ventricular end-diastolic pressure (RVEDP)
- - Mean � 90 mmHg (torr)
- - Normally 80-100 mmHg
- - Represents the average pressure during the cardiac cycle
- - It is the most of the arterial pressures and is an indicator of tissue perfusion
- - MAP <60 mmHg compromises function of vital organs
- PAP � indicates a lung problem
- - Normal values for PAP:
- Systolic 25 mmHg
- Diastolic 8 mmHg
- Mean 14 mmHg
- - The PAP monitors the blood moving into the lungs
- - The PAP can also be referred to as the �afterload� of the right ventricle
- - Is an important measurement in the care of critically ill patients with sepsis, ARDS, pulmonary edema, and myocardial infarction.
- PCWP � indicates a left heart problem
- - Normally 8 mmHg
- Range of 4 to 12 mm Hg
- - Also called pulmonary artery wedge pressure (PAWP)
- - Monitors the blood moving into the left heart
- The PCWP (wedge pressure) represents the pulmonary venous drainage back to the left heart and may be referred to as and will estimate:
- - Left atrial pressure
- - Left atrial filling pressure
- - Left side pre-load
- - Left ventricular filling pressure
- - Left ventricular end-diastolic pressure (LVEDP)
50.How the hemodynamic pressures are measured.
- CVP may be monitored with a Swan-Ganz catheter or from a separate CVP catheter.
- - The CVP catheter is connected to a water manometer, which reads the pressure in cmH2O.
- - Measuring the CVP with a Swan-Ganz catheter gives the pressure in mmHg.
- - Most popular catheter is 7 French with a triple lumen
- - The triple lumen allows infusion of medications and a port from which to obtain blood samples
- - The catheter is inserted through a peripheral vein and is located in the right atria
- The PAP is measured with a balloon-tip, flow directed, pulmonary artery catheter (Swan-Ganz) with the balloon deflated.
- The PA catheter has multiple lumens
- The balloon is used to float the catheter in place and to measure left ventricular filling pressures
- - The catheter is directed through the right side of the heart and is positioned in the pulmonary artery.
4 � channel Swan-Ganz catheter
- The Swan-Ganz catheter is a balloon-tipped catheter made of polyvinyl chloride that is used to measure:
- - Central venous pressure (CVP)
- - Pulmonary artery pressure (PAP)
- - Pulmonary capillary wedge pressure (PCWP)
- The catheter also allows for the aspiration of blood from the pulmonary artery for mixed venous blood gas sampling and injection of fluids to determine cardiac output.
- The distal channel (lumen) is used for the measurement of PAP and for obtaining mixed venous blood from the pulmonary artery.
- The proximal channel (lumen) is used for the measurement of CVP or right atrial pressure and for the injection of fluids to determine cardiac output.
- The balloon inflation channel controls the inflation and deflation of a small balloon, located about 1 cm from the distal tip of the catheter, and is used to measure PCWP.
- The fourth channel is an extra port for the continuous infusion of fluid when necessary.
- This catheter is also equipped with a computer connector to measure cardiac output using the thermodilution technique.
- Note: Some catheters are equipped with only two channels, the distal channel and the balloon inflation channel.