Unit 6: humidifiers and large volume aerosol generators

by Elizabeth Kelley Buzbee AAS, RRT-NPS, RCP

case studies

• CASE STUDY # 1 Mrs. JamaalMrs. Jamaal is a 45 y.o. Lebanese woman

who is s/p intracranial surgery for a brain tumor. She presents in the Recovery Room. The anesthesiologist wants to extubate her and after checking her spontaneous Ve and her IC, he elects to stop bagging her with 100% .

How do you want to assess this patient?

ANSWER:

• You want her VS: • HR is 115 and respiratory rate is 12 bpm

• You want her Sp02 on 100% bagging:• It is 95%

• If the 02 is less than 99% you would like to see an ABG to make a decision• It is pH 7.35 Pa02 320, PaC02 is 35 HC03- 24

• You want to hear bilateral breath sounds: • BBS without rhonchi, crackles or wheezes. BBS

in the bases are present.

• What device do you suggest we get this lady to oxygenate her through her endotracheal tube?

ANSWER:

• A t-tube attached to her endotracheal tube, powered by 02 running into a cool pneumatic aerosol generator

• What Fi02 do you need on the patient’s t-tube?

ANSWER:

• Based on the Fi02:Pa02 formula, we can give 30-40% to achieve a normal Pa02.

• You assemble a t-tube at an Fi02 35%, and you find a 5 inch flex hose. • Where does this part go on the circuit?• Why?

ANSWER:

• You place this 5 inch flex hose downstream from the Brigg’s adaptor to act as a reservoir for the Fi02 and for the mist

• How do you select the Fi02 35%?

ANSWER:

• You dial in the Fi02 on the entrainment device on the cool aerosol generator

• The aerosol generator has a suggested flow rate, can you exceed this flow rate? Can you do less? Why or why not?

ANSWER:

• You can exceed the flow rate if needed but the suggested flow rate is there to prevent you from setting too low a flow rate.

• If the total flow between the set flow and the entrained air is less than the patient’s need, she will entrain room air from around her t-tube so that her delivered Fi02 is less than the 35% she is supposed to get.

• Your patient has been on the t-tube for about 30 minutes and you return to the bedside. You see that the patient is dusky and diaphoretic, her respiratory rate is increased and her HR is faster. Her Sp02 is 78%.

• What do you do?

ANSWER:

Check her BS for wheezing, or for secretions [rhonchi]

she’s not.

Check the flow meter for proper function?

it’s been turned down to zero

Check every part of her t-tube for correct function?

everything is connected

• After you increase the flow rate back to the proper level you watch the patient’s response.

• She is still retracting, tachypnic and tachycardiac and her Sp02 rises to only 82% but no higher.

• What do you do?

ANSWER:

• increase her Fi02 until her Sp02 returns to normal--- and call the doctor

• Re-check her BBS• If that doesn’t work, bag her with

100% ---and call the doctor• Suggest an Arterial blood gas

• You have increased her Fi02 from 35% to 50% and her Sp02 is at 92%

• You get an ABG• Ph is acidic and that her PaC02 is 50 torr

and her Pa02 is 65 torr

• Why is her Pa02 down?• Why is her PaC02 up

answer

• her Pa02 is down because she had to entrain room air from the room so her delivered Fi02 is

• Her PaC02 is up because the entire circuit is now dead space and she’s been rebreathing her C02 all this time

Case study # 2Baby boy Phillip is a 12 hour-old

newborn, who presents with increased respiratory distress in the nursery.

How do you assess this baby?

answer

• VS• His respiratory rate is 66 bpm [fast]• His HR is 150 [fast]

• On inspection he has marked intercostal substernal retractions

• Check BS• He has crackles to all lobes and diminished BS

in the lower lobe

• Check the Sp02• It’s 84% on room air

• Check the ABG• The pH and the PaC02 are normal but the Pa02

is 43 torr

• You suggest what?

answer

• Give supplementary 02 to correct the Sp02 to 92%

• Reassess the VS and Sp02 to assure the 02 is effective

• What 02 device do you select for this patient?

answer

• Heated hood with a blender to mix an exact Fi02

• Your equipment tech delivers the following equipment:• Medium-sized hood• Aerosol hose• Large volume pneumatic aerosol

generator with entrainment control over Fi02.

• You do what?

answer

• The hood is ok, but we must have a heated humidifier to avoid [1] over hydration of the infant [2] to avoid cooling him off too much and dropping his core temperature

• We must have a blender because we need complete control over the Fi02, not just the few Fi02’s we can select on the entrainment device

• What is the problem with dropping a newborn’s core temperature?

answer

• Newborns cannot keep their temperatures up without using up their 02 inside their bodies so that cold can actually cause them to become hypoxic from hyper-metabolic hypoxemia

• They need to be maintained at a neutral thermal zone—• too high we increase their metabolism, • too low we increase their metabolism

Case study # 3Your patient is a 18 year old asthmatic

who presents in the ER with increased respiratory distress. Her X-ray shows evidence of pneumonia with consolidation, and atelectasis.

Because her secretions are thick, the doctor wants to order an ultrasonic nebulizer with saline to mobilize secretions.

You suggest?

answer

• The ultrasonic will cause bronchospasm

• If given alone, the normal saline will cause bronchospasm

• You suggest mobilizing her secretions with SVN with Beta II bronchodilators and normal saline

• Only if she cannot get IC of 10 ml/Kg suggest we administer these drugs with IPPB

• The doctor agrees, and we give her SVN with these drugs Q 2 hours x 3 then are able to drop back down to Q4 hours once she starts responding favorably to the drugs.

• To administer 02 to the patient you suggest a nasal cannula at 5 lpm.

• What type of device do we need to attach to the nasal cannula?

answer

• She needs a cool humidifier that can handle the low flows of the nasal cannula

• When you set up the humidifier, you note that the bubbles don’t rise from the bottom of the reservoir.

• To make sure the device is working correctly you do what?

answer

• If it is a bubble diffuser humidifier or a bubble humidifier or a jet diffuser you expect bubbles,

• If it is a jet humidifier, you will see no bubbles but will see a mist inside the bottle

• You check the [1] flow meter, [2] the connections between it and the humidifier

• You feel for flow out of the humidifier

• Three days later you are rounding up on the floors and you see that this patient has been placed on a face shield powered by a heated pneumatic aerosol.

• You suggest?

answer

• While a heated aerosol is better than cold, aerosols are all potential cholinergic stimulates and can trigger for bronchospasm.

• She need humidification, not a bland aerosol

Case study # 4Patient is Mr. Grant, a 38 year-old

who is status post tracheostomy for protection of his lower airways secondary to brain damage sustained during meningitis.

He is taken off the ventilator.What do you want to assess?

answer

• VS: HR 86 /RR 21 bpm

• BS: clear to all lobes

• X-ray: wnl [normal] with tracheostomy tube in correct position

• Sp02 on current 02: Sp02 95% on Fi02 30%

• ABG: ph 7.36 [wnl] Pa02 120 PaC02 35

• Inspection: no retractions, regular respirations with good chest excursion

• Percussion: wnl

• The doctor wants to put him on a t-tube at 30%

• What do you suggest?• Why?

answer

• He would be more comfortable with a tracheostomy collar than a t-tube

• The Fi02 is OK but may we decrease the Fi02 later once we get a ABG after 20 minutes off the ventilator.

• [NOTE: when he is coming off mechanical ventilation, we expect the WOB to increase so we keep the Fi02 the same or even increase it by 5-10%]

• What type of humidification device do we use with this?

• A trach collar can run off a heated humidifier or an aerosol generator

• Is there a history of wheezing?• Is there a problem with fluid over-

load?

• Your hospital has heated humidifiers so using an entrainment device from a mask, you set up the trach collar.

• What will you need in line in this device?

answer

• Because you are using a heater, you must have a thermometer at the end closest to the patient.

• Because you will have rainout you want to put a water trap into the lowest spot on the circuit.

• You enter the room and note that the humidifier is at the refill line. The nurse’s aid grabs the tube and lifts it so that the water runs back into the humidifier.

• Now there is plenty of water in the humidifier.

• You:

answer

• You tell the nurse’s aide that one must always drain the tube into the water trap or into the trash. Never back into the humidifier for infection control issues

• You, then, replace the humidifier.

• You are rounding and you see that the thermometer at the patient’s end is 29 degrees.

• You do what?

• Increase the heater control, and reassess the temperature in 20 -30 minutes

• You would like to see the temperature 32-34 degrees

• After you return to re check the temperature you see that it is 40 degrees. The patient is diaphoretic

• You do what?

answer

• Without burning yourself or the patient drain the overheated water from the reservoir and re-fill it with cool sterile water

• Reduce the heater and recheck the temperature again.