RESP 210 quiz 4 study guide

Patient Transport: think patient stability

• team

• what do they need to maintain

• risks

• Do not go on a transport unless

  • ALL members of the team are present

• Be sure that patient is able to maintain

  • hemodynamic stability during the transport

• If your patient is

  • hemodynamically unstable (2 – 3 + pressors)

  • and medically complicated

    • make sure the field trip benefits outweigh the risks

Patient Transport: Know when transporting a very unstable/high-PEEP patient may be unsafe. 

• If very high PEEP, be cautious about the transport

• use Kelly clamp between transition from ventilator to

  • AMBU bag

  • or transport circuit

    • don’t lose PEEP!

Patient Transport: battery

Sufficient battery – bring backup

Patient Transport: airway/emergency equipment

• equipment

  • Stethoscope

  • Self-inflating AMBU

  • Emergency airway supplies

  • O2 tanks

• transport vent

  • Portable vent circuit

  • PEEP capacity

  • Sufficient battery – bring backup

  • Vent w/alarms, pressure monitoring, Vt capacity *

  • Make sure vent at destination

Patient Transport: monitoring

• Pulse ox

• Heart rate monitor, ideally with vascular pressure capacity

• CO2 monitor (won’t always see but is recommended for pt safety)

• Do NOT get comfortable at any time during a patient transport

• Watch your patient and the monitoring screens at all times

  • on the way to the destination

  • at the destination

  • and the return back

• Bring portable suction if you don’t think your patient can make it to the destination without coughing up material that could compromise safety

• Be present and involved every time pt moves from bed to bed or onto the vennt set up at your location. This is a high-risk time

• For special transports (iNO, continuous neb, trache etc.), bring specialty supplies

Patient Transport: backup plan

• Bring back up oxygen and batteries in case things go wrong/get delayed

Be able to calculate whether an E-cylinder contains enough oxygen for transport, including an appropriate reserve. 

(Tank pressure - reserve x 0.28) / tank flow in LPM

• 500 PSI common reserve

  • dont use if it mentions how much is left

Know jet nebulizer vs. Aerogen on the ventilator:

• location

• flow, VT, pressure

• alarms

• medications left

• pulm deposition

• Jet nebs

  • Place on the inspiratory limb near the Wye

  • cheaper

  • add flow 6 – 10 LPM depending on the device

  • can change Vt, MV, pressures, triggering, alarms and FiO₂;

    • ↑

      • PIP

      • delivered Vt

      • MV

  • May

    • set off vent alarms

    • make it more difficult for pt to trigger a breath

    • alter the intended pattern of ventilation

  • Leaves substantial medication behind in the cup

  • lower less consistent pulm deposition

• Aerogen does not add flow

  • Place on dry side of the humidifier

  • more expensvie

  • Produces aerosol by vibrating medication through a microscopic mesh

  • Does not alter delivered Vt, pressures, or impact patient triggering

  • Can remain inline

    • no circuit disconnection needed for tx

  • Minimal medication remains in the reservoir

  • Can deliver scheduled or continuous nebulization

  • can be used for non-bronchodilator meds, like:

    • inhaled epoprostenol

    • TXA

    • heparin

  • higher more consistent pulm deposition

Know basic MDI administration through a ventilator circuit and how inspiratory flow/Ti affect delivery. 

• If pt has important home medication in MDI form, may need to give through a vent circuit

• Shake MDI first (prime if necessary) + remove HME

• Set MDI spacer in inspiratory limb of the circuit

• Temporarily ↓ inspiratory flow

• Temporarily ↑ Ti

• Coordinate MDI with precise start of inspiration

• Give one puff at a time

Suctioning: indications

• Patient’s inability to generate acough

• Deterioration of ABG or SpO2 values

• Decreased volume in pressure ventilation

• Increased PIP in volume ventilation

• Changes in monitored flow-volume graphics

Suctioning: monitoring

• Before, during, and after suctioning:

  • BS, RR, and pattern

  • O2 saturation and FiO2

  • Pulse, BP, ECG if available

  • Cough effort

  • Sputum (color, consistency, etc.)

  • ICP if indicated

Suctioning: complications

• Cardiac dysrhythmias

• Hypoxemia or hypoxia

• Airway trauma/bleeding

• Atelectasis or reduction of lung volume

• Increased intracranial pressure

• Bronchospasm

• Loss of PEEP/derecruitment

Do we preooxygenate before suctioning?

yes @100% FIO2

Understand the issues of decompensation when suctioning patient on high PEEP

Loss of PEEP/derecruitment

Know what SpO₂ measures

• SpO2 is a useful early warning system to detect hypoxemia in critically illpatients – keep in mind that SpO2 ≠ SaO2

  • Hypoxemic events in the ICU are associated with

    • apnea

    • airway obstruction

    • equipment failure

    • disconnection

    • sometimes incorrect gas flow settings

How pulse oximetry works

• To differentiate oxygenated Hb from deoxygenated Hb, two wavelengths of light are passed through the sampling site. (660 nm and 940 nm)

  • Deoxygenated Hb absorbs more of the

    • 660 nm (red light)

  • Oxygenated Hb absorbs more of the

    • 940 nm light (infrared)

• Pulse rate is determined from cyclic changes in light absorption:

  • Systole: arterial blood volume ↑ → absorption ↑ → transmitted light ↓

• Pulse oximetry provides continuous, non-invasive measurements of arterial oxygen saturation

• Sensor commonly placed on:

  • finger

  • earlobe

  • forehead

  • bridge of nose

• •Side note: In NICU, location matters.

  • Preductal vs postductal location

The basic relationship between SpO₂/SaO₂ and PaO₂ on the oxyhemoglobin dissociation curve

• SaO2 varies with PaO2 in a ‘sigmoidal’ or S-shaped manner

• When SaO2 is > 90%, PaO2 goes

  • up without much bump in SaO2

• Below 80% SaO2, the PaO2

  • falls more dramatically

• Although 97% is considered a normal adult SaO2, 90% or higher is acceptable for most adult patients

Know when pulse oximetry can lie or become unreliable

• poor perfusion

• motion

  • shivering, tremors, seizures, or patient movement

• probe/site problems

  • incorrect fit, or inappropriate site

• low saturations

• ambient light

• Nail polish, artificial nails, or tattoo ink

Does the SpO₂ fit the patient?

• Check the pleth and pulse agreement

• reposition or warm the site

• confirm with an ABG when clinically necessary

Know COHb vs. MetHb: CO can give a falsely reassuring SpO₂; significant MetHb tends toward ~85%;

• Carboxyhemoglobin (COHb)

  • A standard pulse oximeter cannot distinguish COHb from O₂Hb.

  • COHb may therefore produce a falsely reassuring SpO₂.

  • A normal SpO₂ does not rule out carbon monoxide poisoning.

• Methemoglobin (MetHb)

  • MetHb absorbs 660-nm red light and 940-nm infrared light nearly equally

  • As MetHb increases, the red-to- infrared absorption ratio approaches

  • As MetHb becomes significant, the displayed SpO₂ trends toward approximately 85% and no longer reliably reflects the true arterial saturation

    • suspected dyshemoglobinemia requires co-oximetry.

• Suspect COHb or MetHb? Order a blood gas with co-oximetry to directly measure O₂Hb, HHb, COHb, and MetHb

Review right and left shifts of the oxyhemoglobin dissociation curve and what happens to Hb-O₂ affinity.

• right shift

  • ↓

    • pH

  • ↑

    • CO2

    • 2-3 DPG

    • temp

    • affinity for Hb

• left shift

  • ↑

    • pH

  • ↓

    • CO2

    • 2-3 DPG

    • temp

    • affinity for Hb

Know the difference between capnometry, capnography, and a capnogram

• Capnometry

  • measurement of exhaled CO2

    • (numerically without a waveform)

• Capnography

  • continuous display of exhaled CO2 concentrations as a graphic waveform

• Capnogram

  • graphic waveform of CO2 against time

Major clinical uses of capnography—including ET tube verification, ventilation/CO₂ elimination, V/Q assessment, perfusion, and detecting rebreathing. 

• Monitoring V/Q relationships and response to therapy

• Verify ET tube placement

• Monitor adequacy of pulmonary and coronary blood flow

• Screening for pulmonary embolism

• Detection of CO2 rebreathing and effects of sedation/neuromuscular blockade

• Monitoring CO2 elimination

• Optimizing mechanical ventilation

Know the four phases of a normal capnogram, including where PETCO₂/ETCO₂ is measured, and recognize the normal waveform.

Phase 1 - the initial gas exhaled is from the conducting airways, which contain low levels of CO2 (mostly dead space).

Phase 2 - alveolar gas containing CO2 mixes with gas in the anatomical airways and the CO2 concentration increases.

Phase 3 - the curve plateaus as alveolar gas is exhaled (this phase is often referred to as the alveolar plateau). Note that the concentration of CO2 at the endof the alveolar phase (just before inspiration begins) is called the end-tidal PCO2 or PETCO2.

Phase 4 - Inspiration, the concentration falls to zero.

Capnogram: Phase 1

Phase 1 - the initial gas exhaled is from the conducting airways, which contain low levels of CO2 (mostly dead space).

Capnogram: Phase 2

Phase 2 - alveolar gas containing CO2 mixes with gas in the anatomical airways and the CO2 concentration increases.

Capnogram: Phase 3

where is PETCO₂/ETCO₂ measured?

Phase 3 - the curve plateaus as alveolar gas is exhaled (this phase is often referred to as the alveolar plateau). Note that the concentration of CO2 at the endof the alveolar phase (just before inspiration begins) is called the end-tidal PCO2 or PETCO2.

Capnogram: Phase 4

Phase 4 - Inspiration, the concentration falls to zero.

Know normal PETCO₂ (~35–38 mmHg) and its relationship to PaCO₂ (normally ~2–5 mmHg lower); understand why an increased PaCO₂–PETCO₂ gradient suggests increased dead space/V-Q problems such as pulmonary embolism. 

• The normal end-tidal value is approximately:

  • 35- 38 mmHg

  • or around 5% PETCO2.

  • Trends are more important than value.

• PETCO2 normal =

  • ~ 3 to 5mmHg less than PaCO2

• *Why would you have a wide gradient with your PaCO2 and your PETCO2? What could be the problem?

  • *Pulmonary embolism

    • Will have

      • low PETCO2

      • high PaCO2.

• *Other dead space issues

Be able to interpret changes in the capnogram/PETCO₂: sudden drop to zero

A sudden drop in CO2 to ZERO always indicates a problem such as:

• Kinked ET-tube

• CO2 analyzer defective

• Disconnection

• Ventilator defective

• Patient stopped breathing, circulatory arrest

• Condensation affecting sensor

• Embolism

• Sudden decrease in blood pressure

Be able to interpret changes in the capnogram/PETCO₂: sudden decrease, or sudden increase—and connect them to likely causes such as disconnection/airway problems, poor perfusion or compressions, ROSC, and changes in CO₂ production/metabolism.

A sudden decrease in CO2 but not to 0 may be caused by:

• Leakage in the respiratory system

  • (low airway pressure)

• Obstruction (high airway pressure)

• Poor compressions

Be able to interpret changes in the capnogram/PETCO₂: s sudden increase—and connect them to likely causes such as disconnection/airway problems, poor perfusion or compressions, ROSC, and changes in CO₂ production/metabolism.

A sudden increase in PETCO2 can be caused by:

• Injection of sodium bicarbonate

• Sudden release of tourniquet

• Sudden increase in blood pressure

• Achieved ROSC

Production of CO2 is determined by the metabolic rate

*Factors that INCREASE metabolic rate and CO2 production:

- Fever, sepsis, hyperthyroidism, seizures

*Factors that DECREASE metabolic rate and CO2 production:

- Hypothermia, starvation, sedation

Know how to read the basic pressure, flow, and volume vs. time waveforms and recognize what the patient/ventilator is doing.

y axis = flow

x axis = time

a-b = inspiration

b-c = expiration

d= peak insp flow

e= PEFR

Know how to read the basic flow waveforms

Be able to recognize air trapping/auto-PEEP and inadequate expiratory time, including what the flow waveform should do before the next breath begins. 

• not enough time to exhale

type of disease from graph?

Increase Ti on pt A, will you get more vol?

Use graphics to identify airway obstruction, changes in compliance, patient triggering/active exhalation, flow demand, and patient–ventilator synchrony.

type of breath?

mandatory breath

type of breath?

spontaneous breath

type of breath?

assisster breath

analyze graph: ACVC

static compliance line

Understand how changes in Pplat, PEEP, Vt and compliance relate to one another. Know Cstat = Vte/(Pplat − PEEP)

PATIENT A

• Vte 500 ml

• PEEP 5 cmH2O

• Pplat 20 cmH2O

PATIENT B

• Vte 500 ml

• PEEP 5 cmH2O

• Pplat 30 cmH2O

Without using a calculator, tell me who has the best static compliance?

• patient A

  • lower pPlat

overdistention graph

zone & inflection points on graphics

Be able to identify P-V loop compliance issues in volume mode

Be able to identify P-V loop compliance issues in pressure mode

Be able to identify LIP and place for optimal PEEP; be able to identify HIP and identify the dangers of that point; know how to make changes to the vent to solve overdistention or inadequate PEEP based on P-V loop

Be able to look at a graphic and determine the likely ventilator mode/problem and appropriate correction—not just name the waveform.

• Is the patient getting enough time to exhale?

  • → Air trapping / auto-PEEP

• Is it taking too long to get air out?

  • → Airway obstruction

• Did our treatment make a difference?

  • → Response to bronchodilator therapy

• Is the patient comfortable with the breath?

  • → Inspiratory flow demand & patient–ventilator synchrony

• What is the patient doing?

  • → Triggering effort & active exhalation