Oxygenation, Ventilation And Ventilator Management In The First 24 Hours

Oxygenation, Ventilation, Oxygenation, Ventilation, and Ventilator Management and Ventilator Management

in the First 24 Hoursin the First 24 Hours

Robert L. Huck, M.D.Robert L. Huck, M.D.

Financial disclosures: Up to my ___ in Financial disclosures: Up to my ___ in alligators, I’m just trying to help drain the swamp alligators, I’m just trying to help drain the swamp (i.e., none)(i.e., none)A “nuts and bolts” talk (more “nuts” than “bolts”?, A “nuts and bolts” talk (more “nuts” than “bolts”?, I’ll leave you to decide)I’ll leave you to decide)You getting my biases, and those of your local You getting my biases, and those of your local pulmonary support group (but no we are not a pulmonary support group (but no we are not a 12 step program)12 step program)Hopefully, knowing our thinking will smooth Hopefully, knowing our thinking will smooth transitionstransitions

Common In Hospital Etiologies for Common In Hospital Etiologies for Respiratory FailureRespiratory Failure

Excess narcotics or Excess narcotics or sedativessedatives

In hospital aspirationsIn hospital aspirations

Cardiopulmonary Cardiopulmonary arrestarrest

COPDCOPD

CHFCHF

PneumoniaPneumonia

Drug overdoseDrug overdose

AsthmaAsthma

PancreatitisPancreatitis

StrokeStroke

SepsisSepsis

Measures of OxygenationMeasures of Oxygenation

Arterial oxygen saturation (SaO2)Arterial oxygen saturation (SaO2)Arterial oxygen tension (paO2)Arterial oxygen tension (paO2)Alveolar to arterial oxygen difference (A-a Alveolar to arterial oxygen difference (A-a gradient) PAO2=(FIO2x[Patm-PH2O])-gradient) PAO2=(FIO2x[Patm-PH2O])-(PaCO2/R)(PaCO2/R)PAO2/FIO2PAO2/FIO2A/a oxygen ratioA/a oxygen ratioOxygenation index Oxygenation index ([{MAPxFIO2}/PaO2]x100)([{MAPxFIO2}/PaO2]x100)

Mechanisms of HypoxemiaMechanisms of Hypoxemia

HypoventilationHypoventilation

Ventilation/perfusion mismatchVentilation/perfusion mismatch

Right to left shuntRight to left shunt

Diffusion limitationDiffusion limitation

Decrease inspired oxygen tensionDecrease inspired oxygen tension

Monitoring of OxygenationMonitoring of Oxygenation

Clinical: subjective dyspnea, cyanosis, Clinical: subjective dyspnea, cyanosis, mental status changes (usually restless- mental status changes (usually restless- ness, agitation, or confusion, particularly in ness, agitation, or confusion, particularly in the elderly)the elderly)

Pulse oxymetry Pulse oxymetry

Arterial blood gasesArterial blood gases

Pulse OxymetryPulse Oxymetry

Arterial oxygen saturation is Arterial oxygen saturation is physiologically the more important numberphysiologically the more important number

O2 Content=(1.34 ml/gm x Hgb gm/dl x O2 Content=(1.34 ml/gm x Hgb gm/dl x SaO2) + (0.0031x PaO2)SaO2) + (0.0031x PaO2)

Accuracy:Accuracy: Best in normal or near normal rangeBest in normal or near normal range +/- 2% in Caucasians, +/- 4% in blacks+/- 2% in Caucasians, +/- 4% in blacks

Pulse OxymetryPulse Oxymetry

Potential sources of error:Potential sources of error: Abnormal hemoglobins: carboxyhemoglobin, Abnormal hemoglobins: carboxyhemoglobin,

methemoglobinmethemoglobin HypoperfusionHypoperfusion HypothermiaHypothermia AnemiaAnemia Venous congestionVenous congestion PigmentationPigmentation Nail polishNail polish Vital dyes (e.g. methylene blue)Vital dyes (e.g. methylene blue)

Monitoring Oxygenation Monitoring Oxygenation


Effected by temperatureEffected by temperature

Provides information on ventilation and Provides information on ventilation and acid base balance as well as oxygenationacid base balance as well as oxygenation

Relationship of PaO2 and SaO2: the Relationship of PaO2 and SaO2: the oxyhemoglobin dissociation curveoxyhemoglobin dissociation curve

Monitoring of VentilationMonitoring of Ventilation


End tidal CO2 monitors (a complicated End tidal CO2 monitors (a complicated subject but useful for trending)subject but useful for trending)

CO2 detectorsCO2 detectors Useful for confirming ET placementUseful for confirming ET placement Requires perfusionRequires perfusion

Indications for Mechanical Indications for Mechanical VentilationVentilation

Refractory hypoxemiaRefractory hypoxemia pO2 <55 on supplemental oxygen (usually 100% NRB mask)pO2 <55 on supplemental oxygen (usually 100% NRB mask) Alveolar to arterial oxygen gradient >450 on FIO2 =1.0Alveolar to arterial oxygen gradient >450 on FIO2 =1.0 paO2/pAO2 <0.15paO2/pAO2 <0.15

Inadequate ventilation and respiratory acidosis (pH<7.23 Inadequate ventilation and respiratory acidosis (pH<7.23 andand decreased level of consciousness) decreased level of consciousness)Non sustainable work of breathingNon sustainable work of breathing

Respiratory rate > 35-40 breaths per minuteRespiratory rate > 35-40 breaths per minute Marked use of accessory muscleMarked use of accessory muscle Metabolic acidosis, i.e. lactic acidosis (especially if due to Metabolic acidosis, i.e. lactic acidosis (especially if due to

respiratory muscle work (e.g. asthma with normal pCO2 and respiratory muscle work (e.g. asthma with normal pCO2 and decreased pH)decreased pH)

RR<10, NIFM < -30 cm H2O, Vital Capacity < 1L or < 10 ml/kgRR<10, NIFM < -30 cm H2O, Vital Capacity < 1L or < 10 ml/kg

Refractory Hypoxemia?Refractory Hypoxemia?

Remember 100% by NRB mask does Remember 100% by NRB mask does notnot equal 100% FIO2equal 100% FIO2

The true FIO2 depends on both flaps The true FIO2 depends on both flaps being in place, seal, and the patient’s being in place, seal, and the patient’s inspiratory flow rate and entrainment of inspiratory flow rate and entrainment of room air. You can try increasing the O2 room air. You can try increasing the O2 flow rate (“oxymask” or mask plus nasal flow rate (“oxymask” or mask plus nasal prongs) or O2 reservoirprongs) or O2 reservoir

Indications for Mechanical Indications for Mechanical VentilationVentilation

Refractory hypoxemiaRefractory hypoxemia pO2 <55 on supplemental oxygen (usually 100% NRB mask)pO2 <55 on supplemental oxygen (usually 100% NRB mask) Alveolar to arterial oxygen gradient >450 on FIO2 =1.0Alveolar to arterial oxygen gradient >450 on FIO2 =1.0 paO2/pAO2 <0.15paO2/pAO2 <0.15

Inadequate ventilation and respiratory acidosis (pH<7.23 Inadequate ventilation and respiratory acidosis (pH<7.23 andand decreased level of consciousness) decreased level of consciousness)Non sustainable work of breathingNon sustainable work of breathing

Respiratory rate > 35-40 breaths per minuteRespiratory rate > 35-40 breaths per minute Marked use of accessory muscleMarked use of accessory muscle Metabolic acidosis, i.e. lactic acidosis (especially if due to Metabolic acidosis, i.e. lactic acidosis (especially if due to

respiratory muscle work (e.g. asthma with normal pCO2 and respiratory muscle work (e.g. asthma with normal pCO2 and decreased pH)decreased pH)

RR<10, NIFM < -30 cm H2O, Vital Capacity < 1L or < 10 ml/kgRR<10, NIFM < -30 cm H2O, Vital Capacity < 1L or < 10 ml/kg

Indications for Mechanical Indications for Mechanical Ventilation Ventilation

Any of the indications above Any of the indications above andand you are you are thinking: “I can’t fix this any time soon.”, thinking: “I can’t fix this any time soon.”, think intubation and invasive mechanical think intubation and invasive mechanical ventilationventilationIf you are thinking: “I can fix this if I can If you are thinking: “I can fix this if I can just buy enough time.”, then think- “non just buy enough time.”, then think- “non invasive ventilation!” ( assuming no invasive ventilation!” ( assuming no contraindications to NIPPV)contraindications to NIPPV)

Indications for NIPPVIndications for NIPPV

NIPPV is primarily a temporizing measure NIPPV is primarily a temporizing measure for ventilatory support.for ventilatory support.

Buying time for other therapies (i.e. Buying time for other therapies (i.e. diuretics, bronchodilators, etc.) to workdiuretics, bronchodilators, etc.) to work

NIPPV generally augments, but does not NIPPV generally augments, but does not replace, spontaneous ventilatory effortsreplace, spontaneous ventilatory efforts

Indications for Non-Invasive Indications for Non-Invasive VentilationVentilation

Alert, cooperative patients not requiring Alert, cooperative patients not requiring emergent intubation with a need for relatively emergent intubation with a need for relatively short short term ventilatory supportterm ventilatory support

Problems known to respond to NIPPVProblems known to respond to NIPPV COPD exacerbations with moderate COPD exacerbations with moderate

hypercapnea(pCO2>45, <100 mmHg), and acidosis hypercapnea(pCO2>45, <100 mmHg), and acidosis (pH <7.3, >7.00-7.10)(pH <7.3, >7.00-7.10)

Acute cardiogenic pulmonary edemaAcute cardiogenic pulmonary edema Hypoxemic respiratory failure (other than ARDS)Hypoxemic respiratory failure (other than ARDS) Post-extubation respiratory failure Post-extubation respiratory failure

Contraindications to NIPPVContraindications to NIPPV

Cardiac or respiratory arrestCardiac or respiratory arrestInability to cooperate, protect airway, or clear Inability to cooperate, protect airway, or clear secretionssecretionsSignificantly impaired consciousness(except Significantly impaired consciousness(except possibly COPD) possibly COPD) Non respiratory organ failuresNon respiratory organ failuresFacial trauma, surgery or deformityFacial trauma, surgery or deformityHigh aspiration risk (e.g., the pregnant High aspiration risk (e.g., the pregnant asthmatic)asthmatic)Prolonged ventilatory support anticipatedProlonged ventilatory support anticipatedRecent esophageal anastomosisRecent esophageal anastomosis

NIPPV InterfacesNIPPV Interfaces

In acute care settings, generally start with a full In acute care settings, generally start with a full face maskface maskMost patients with acute respiratory failure are Most patients with acute respiratory failure are mouth breathers. Nasal ventilation results in a mouth breathers. Nasal ventilation results in a large oral air leaklarge oral air leakNormally the nasal airway contributes 50% of Normally the nasal airway contributes 50% of total airway resistancetotal airway resistanceFull face masks make monitoring and Full face masks make monitoring and management of aspiration more difficultmanagement of aspiration more difficultPatients on chronic CPAP or BiPAP may do Patients on chronic CPAP or BiPAP may do better with their usual kind of mask. better with their usual kind of mask.

NIPPV ModesNIPPV Modes

Mostly at this institution NIPPV equates to Mostly at this institution NIPPV equates to bilevel positive airway pressure with a bilevel positive airway pressure with a guaranteed back up respiratory rate.guaranteed back up respiratory rate.Can be used with assist control mode of a Can be used with assist control mode of a standard ICU ventilator (for greater standard ICU ventilator (for greater assurance of minute ventilation)assurance of minute ventilation)Can be used with pressure support Can be used with pressure support ventilation with ICU ventilator (for better ventilation with ICU ventilator (for better patient synchrony and comfort)patient synchrony and comfort)

NIPPV MonitoringNIPPV Monitoring

Monitor: Level of consciousness, vital Monitor: Level of consciousness, vital signs, and ABG’s.signs, and ABG’s.

Improvement should be apparent in the Improvement should be apparent in the first 30-120 miuntesfirst 30-120 miuntes

If no improvement, proceed to If no improvement, proceed to endotracheal intubationendotracheal intubation

Advantages of NIPPVAdvantages of NIPPV

Lower mortality in acute respiratory failure Lower mortality in acute respiratory failure (primarily COPD and CHF)-probable (primarily COPD and CHF)-probable selection bias for less severe patientsselection bias for less severe patients

Reduced nosocomial infectionReduced nosocomial infection

Decrease length of stayDecrease length of stay

Better patient comfortBetter patient comfort

Endotracheal IntubationEndotracheal Intubation

The patient is going down the tube, so you The patient is going down the tube, so you decide the tube is going down the patient.decide the tube is going down the patient.

How to intubate is another talkHow to intubate is another talk

Fast forward - the patient is intubated, now Fast forward - the patient is intubated, now what?what?

A couple of caveats from the intubation processA couple of caveats from the intubation process Do not use succinylcholine, a depolarizing Do not use succinylcholine, a depolarizing

neuromuscular blocker, for hyperkalemic patients or neuromuscular blocker, for hyperkalemic patients or patients with seizurespatients with seizures

Etomidate causes acute adrenal suppressionEtomidate causes acute adrenal suppression

Goals of Mechanical Ventilation: Goals of Mechanical Ventilation: Clinical Clinical

Relieve respiratory distressRelieve respiratory distressImprove hypoxemiaImprove hypoxemiaAlleviate respiratory acidosisAlleviate respiratory acidosisReverse ventilatory muscle fatigueReverse ventilatory muscle fatigueReduce systemic or myocardial oxygen Reduce systemic or myocardial oxygen consumptionconsumptionPermit sedation or neuromuscular blockadePermit sedation or neuromuscular blockadePrevent or improve atalectasisPrevent or improve atalectasisStabilize the chest wallStabilize the chest wall

Goals on Mechanical Ventilation: Goals on Mechanical Ventilation: Physiologic goalsPhysiologic goals

Support gas exchange: arterial Support gas exchange: arterial oxygenation and alveolar ventilationoxygenation and alveolar ventilation

Reduce metabolic cost of breathing by Reduce metabolic cost of breathing by unloading respiratory muscles.unloading respiratory muscles.

Avoid ventilator associated lung injuriesAvoid ventilator associated lung injuries

Ventilator Set UpVentilator Set Up

Things you need to specify:Things you need to specify:Ventilator mode (more on this coming)Ventilator mode (more on this coming)FIO2 – start with 100%, unless you are FIO2 – start with 100%, unless you are sure the patient’s lungs are normal, e.g. sure the patient’s lungs are normal, e.g. drug overdose, then 40% is OKdrug overdose, then 40% is OKRespiratory rateRespiratory rateEnd expiratory pressure.End expiratory pressure.Use the ventilator “bundle” order sheet. It Use the ventilator “bundle” order sheet. It will prompt you.will prompt you.

Ventilator Set Up: ModesVentilator Set Up: Modes

Poll: Volume control versus Pressure Poll: Volume control versus Pressure control?control?

Available modes:Available modes: Volume control: A/C, SIMV, CMV Volume control: A/C, SIMV, CMV Pressure control: PCVPressure control: PCV Flow limited: PSV (pressure support Flow limited: PSV (pressure support

ventilation)ventilation) Time limited: Home ventilatorsTime limited: Home ventilators


Each mode has things you need to specifyEach mode has things you need to specify

In general, use the mode you trained with, and In general, use the mode you trained with, and are comfortable usingare comfortable using

Our Bias: If you are starting volume controlled Our Bias: If you are starting volume controlled ventilation for acute respiratory failure, start with ventilation for acute respiratory failure, start with Assist Control Ventilation.Assist Control Ventilation. Advantage: Minimizes WOB. The patient only has to Advantage: Minimizes WOB. The patient only has to

trigger the ventilator.trigger the ventilator. Disadvantage: Every breath is a positive pressure Disadvantage: Every breath is a positive pressure

breath, which impairs venous return.breath, which impairs venous return.


SIMV: synchronized intermittent mandatory SIMV: synchronized intermittent mandatory ventilationventilation Allows spontaneous breaths between mandatory Allows spontaneous breaths between mandatory

machine breaths. Mandated breaths are machine breaths. Mandated breaths are “synchronized” to be delivered when the patient is “synchronized” to be delivered when the patient is trying to inspire.trying to inspire.

Originally this was a “weaning” modeOriginally this was a “weaning” mode Advantage: The patient can set minute ventilation in Advantage: The patient can set minute ventilation in

excess of set parameters, less muscle atrophyexcess of set parameters, less muscle atrophy Disadvantage: Patient does all the work of Disadvantage: Patient does all the work of

spontaneous breaths plus ventilator imposed workspontaneous breaths plus ventilator imposed work The acute concern is respiratory muscle fatigueThe acute concern is respiratory muscle fatigue


SIMV: synchronized intermittent SIMV: synchronized intermittent mandatory ventilationmandatory ventilation A/C vs. SIMV: If goal in the first 24 hrs is to A/C vs. SIMV: If goal in the first 24 hrs is to

reduce work of breathing and respiratory reduce work of breathing and respiratory muscle work and fatigue, A/C is superiormuscle work and fatigue, A/C is superior

Effect on work of breathing is really only Effect on work of breathing is really only different with SIMV if the patient breaths different with SIMV if the patient breaths above the set ventilator rate.above the set ventilator rate.


Volume controlled ventilation:Volume controlled ventilation: FIO2FIO2 Mode: A/C, SIMVMode: A/C, SIMV Tidal volume (usually 10ml/kg ideal weight, Tidal volume (usually 10ml/kg ideal weight,

realize normal spontaneous tidal volume is 5-realize normal spontaneous tidal volume is 5-6ml/kg)6ml/kg)

Respiratory rate Respiratory rate Positive end expiratory pressure.Positive end expiratory pressure.


Pressure control ventilation vs. Volume Pressure control ventilation vs. Volume controlled ventilationcontrolled ventilationVolume controlled ventilation delivers a set Volume controlled ventilation delivers a set minute ventilation, unless pressure limits are minute ventilation, unless pressure limits are exceeded, then some portion of the set minute exceeded, then some portion of the set minute volume is “dumped” (which takes time, so actual volume is “dumped” (which takes time, so actual airway pressure may exceed desired airway airway pressure may exceed desired airway pressures trying to deliver the preset volumes)pressures trying to deliver the preset volumes)How much volume actually gets delivered How much volume actually gets delivered depends on the patient’s airway resistance and depends on the patient’s airway resistance and lung compliance, theoretically minute ventilation lung compliance, theoretically minute ventilation is “guaranteed.”is “guaranteed.”


Volume controlled ventilation vs. Pressure Volume controlled ventilation vs. Pressure controlled ventilationcontrolled ventilation Pressure controlled ventilation increases airway Pressure controlled ventilation increases airway

pressure to the preset inspiratory pressure.pressure to the preset inspiratory pressure. The actual tidal volume delivered depends on the The actual tidal volume delivered depends on the

patient’s airway resistance and lung compliance. patient’s airway resistance and lung compliance. Actual minute volume delivered can vary as these Actual minute volume delivered can vary as these change.change.

Advantage: Limits peak airway pressures and Advantage: Limits peak airway pressures and possible barotraumapossible barotrauma

Disadvantage: Minute ventilation may be inadequate Disadvantage: Minute ventilation may be inadequate for metabolic demandsfor metabolic demands


Pressure support ventilation:Pressure support ventilation: Also originally a “weaning” modeAlso originally a “weaning” mode Requires a patient with intact respiratory drive Requires a patient with intact respiratory drive

and spontaneous breathing, i.e. will not and spontaneous breathing, i.e. will not ventilate an apneic patient.ventilate an apneic patient.

Augments spontaneous tidal volume, Augments spontaneous tidal volume, depending on the patients airway resistance depending on the patients airway resistance and lung complianceand lung compliance

Advantage: Less asynchrony with the Advantage: Less asynchrony with the ventilator and improved patient comfort ventilator and improved patient comfort


Time limited ventilation:Time limited ventilation: Delivers preset flow for preset time. Tidal volume Delivers preset flow for preset time. Tidal volume

depends on airway resistance and lung compliance.depends on airway resistance and lung compliance. Often used in home ventilators: rugged , cheap, Often used in home ventilators: rugged , cheap,

simple, dependable, but hospital RT’s (and pulmonary simple, dependable, but hospital RT’s (and pulmonary doc’s) are often not familiar with themdoc’s) are often not familiar with them

If home ventilated patient has respiratory problems on If home ventilated patient has respiratory problems on their ventilator, take them off theirs and put them on their ventilator, take them off theirs and put them on oursours

You probably will not see these patientsYou probably will not see these patients


Pressure control ventilation:Pressure control ventilation: FIO2FIO2 Inspiratory pressure (IPAP) (as in BiPAP)Inspiratory pressure (IPAP) (as in BiPAP) Expiratory pressure (EPAP) (EPAP =PEEP)Expiratory pressure (EPAP) (EPAP =PEEP) Delta P, the change in pressure. This Delta P, the change in pressure. This mustmust

equal IPAP-EPAPequal IPAP-EPAP Slope (how fast IPAP is achieved), Slope (how fast IPAP is achieved),

usually, .1-.3, determines I:E ratiousually, .1-.3, determines I:E ratio Respiratory rateRespiratory rate


Pressure control ventilation:Pressure control ventilation: Once ventilation is started, you need to Once ventilation is started, you need to

assess if the tidal volume and minute assess if the tidal volume and minute ventilation that results are reasonable for the ventilation that results are reasonable for the patient’s situation and metabolic demandspatient’s situation and metabolic demands

Check ABG’s to be sureCheck ABG’s to be sure


Issues you do not have to specify, but RT has to Issues you do not have to specify, but RT has to set or cope with that you need to be aware ofset or cope with that you need to be aware of Triggering sensitivity and relation to end expiratory Triggering sensitivity and relation to end expiratory

pressurepressure I:E ratioI:E ratio Inspiratory flow rates and patterns (square wave vs. Inspiratory flow rates and patterns (square wave vs.

accelerating or decelerating flow)accelerating or decelerating flow) These effect airway pressures and patient synchrony These effect airway pressures and patient synchrony

with the ventilatorwith the ventilator You need to You need to listenlisten, if RT says there is a problem with , if RT says there is a problem with

your ventilator settings (e.g., If the patient does not your ventilator settings (e.g., If the patient does not have adequate time to exhale between breaths you have adequate time to exhale between breaths you are headed for trouble)are headed for trouble)

Tips on Starting Mechanical Tips on Starting Mechanical VentilationVentilation

RememberRemember, the respiratory therapists and ICU nurses , the respiratory therapists and ICU nurses are your are your friendsfriends! They really do, do all this, all the time. ! They really do, do all this, all the time. ListenListen, to them! If you disagree, explain your reasoning, , to them! If you disagree, explain your reasoning, they they willwill (believe it or not) listen to you! If you can’t (believe it or not) listen to you! If you can’t articulate it, think again!articulate it, think again!CheckCheck thethe chestchest xray!xray! (The crisis is (The crisis is notnot “over” just “over” just because the tube is in!)because the tube is in!)Positive pressure ventilation initially reduces venous Positive pressure ventilation initially reduces venous return, cardiac output, and return, cardiac output, and bloodblood pressure!pressure! Be prepared! Be prepared! (especially, if the patient was possibly intravascularly (especially, if the patient was possibly intravascularly volume depleted prior to intubation). It is volume depleted prior to intubation). It is notnot necessarily necessarily “sepsis”, just because the blood pressure goes down “sepsis”, just because the blood pressure goes down after intubation. Start with IV fluids.after intubation. Start with IV fluids.

Respiratory Distress on Respiratory Distress on Mechanical VentilationMechanical Ventilation

The tools you need: a stethoscope, a The tools you need: a stethoscope, a chest xay, and your brainchest xay, and your brainDisconnect patient from ventilator and Disconnect patient from ventilator and assist ventilation with bagging.assist ventilation with bagging.If the patient is easy to ventilate with If the patient is easy to ventilate with bagging and this solves the distress = bagging and this solves the distress = ventilator problemventilator problemIf the patient hard to ventilate with bagging If the patient hard to ventilate with bagging and still in distress = patient problemand still in distress = patient problem

Respiratory Distress on Mechanical Respiratory Distress on Mechanical Ventilation: Ventilator ProblemsVentilation: Ventilator Problems

Inadequate ventilator settings:Inadequate ventilator settings: Inadequate inspiratory flow rate or pressure- Inadequate inspiratory flow rate or pressure-

previously the most common cause. Rarer now with previously the most common cause. Rarer now with modern ventilators with high flow rates and ability to modern ventilators with high flow rates and ability to meet patients inspiratory flow demands. Dyspneic meet patients inspiratory flow demands. Dyspneic patient have high inspiratory flow demands, even if patient have high inspiratory flow demands, even if their own spontaneous tidal volumes and minute their own spontaneous tidal volumes and minute ventilation are inadequate.ventilation are inadequate.

Can be suspected from ventilator graphic displays, Can be suspected from ventilator graphic displays, take your cues from the respiratory therapists. take your cues from the respiratory therapists.


Inadequate FIO2- should be obvious from oxygen Inadequate FIO2- should be obvious from oxygen saturation or ABG’ssaturation or ABG’sInadequate tidal volumes - The patient may want higher Inadequate tidal volumes - The patient may want higher than set tidal volumes. This is particularly true for than set tidal volumes. This is particularly true for neuromuscular patients and probably involves neuromuscular patients and probably involves intrapulmonary stretch receptors. Given the possibilities intrapulmonary stretch receptors. Given the possibilities of “volutrauma”, increasing tidal volume is not of “volutrauma”, increasing tidal volume is not necessarily good for them, but short term (i.e. a few necessarily good for them, but short term (i.e. a few hours) it is ok to increase the tidal volume until they are hours) it is ok to increase the tidal volume until they are satisfied (and call us in the morning, unless airway satisfied (and call us in the morning, unless airway pressures are excessive)pressures are excessive)


Incorrect positive end expiratory pressure, Incorrect positive end expiratory pressure, especially due to intrinsic PEEPespecially due to intrinsic PEEPIncorrect trigger sensitivity (the patient has to Incorrect trigger sensitivity (the patient has to work too hard to trigger the next breath)work too hard to trigger the next breath)Example: Intrinsic PEEP +10 cm with trigger Example: Intrinsic PEEP +10 cm with trigger sensitivity – 2cm (from atmospheric=0), patient sensitivity – 2cm (from atmospheric=0), patient effort to trigger next breath = -12cmeffort to trigger next breath = -12cmRemedy: Measure intrinsic PEEP, set ventilator Remedy: Measure intrinsic PEEP, set ventilator PEEP at 80% of intrinsic PEEP, and set trigger PEEP at 80% of intrinsic PEEP, and set trigger sensitivity at -2 cm below set PEEP ( in this case sensitivity at -2 cm below set PEEP ( in this case +6 cm relative to atmospheric. Patient effort to +6 cm relative to atmospheric. Patient effort to trigger next breath -4cmtrigger next breath -4cm

Respiratory distress on Mechanical Respiratory distress on Mechanical Ventilation: Ventilator factorsVentilation: Ventilator factors

Ventilator circuit leakVentilator circuit leak

Ventilator malfunctionVentilator malfunction

If the patient is OK off the ventilator, being If the patient is OK off the ventilator, being assisted with bagging, these are the RT’s assisted with bagging, these are the RT’s problems. Have them fix them or get a problems. Have them fix them or get a new ventilator.new ventilator.

Your problem: Solved!Your problem: Solved!

Respiratory Distress on Mechanical Respiratory Distress on Mechanical Ventilation: Patient ProblemsVentilation: Patient Problems

Airway problems (increased peak airway pressure – Airway problems (increased peak airway pressure – plateau pressure, meaning airway resistance has plateau pressure, meaning airway resistance has increased, parenchymal compliance is not changed) increased, parenchymal compliance is not changed) (i.e., the airways have a problem, the lung is no stiffer)(i.e., the airways have a problem, the lung is no stiffer)Pulmonary parenchymal problems-(peak airway Pulmonary parenchymal problems-(peak airway pressure- plateau pressure unchanged or decreased, pressure- plateau pressure unchanged or decreased, meaning air way resistance is unchanged, parenchymal meaning air way resistance is unchanged, parenchymal compliance has decreased) (i.e., more pressure required compliance has decreased) (i.e., more pressure required to create the same change in volume with no increase in to create the same change in volume with no increase in airway resistance = the lung is stiffer)airway resistance = the lung is stiffer)Extrapulmonary problems, i.e. the problem is around the Extrapulmonary problems, i.e. the problem is around the lungs but not in them.lungs but not in them.

Respiratory Distress on Mechanical Respiratory Distress on Mechanical Ventilation: Endotracheal Tube Ventilation: Endotracheal Tube

ProblemsProblemsAirway Problems:Airway Problems:Endotracheal tube: (It’s the tube, stupid!)Endotracheal tube: (It’s the tube, stupid!)

Patient is biting the tube (bite block, paralysis)Patient is biting the tube (bite block, paralysis) The tube is occluded with secretions, foreign body, or blood (try The tube is occluded with secretions, foreign body, or blood (try

forcing it out the distal end with a suction catheter or a stylette or forcing it out the distal end with a suction catheter or a stylette or “tube changer”, or calling for bronchoscopy. Extubate and “tube changer”, or calling for bronchoscopy. Extubate and reintubate, if the problem is acute, but you risk losing a secure reintubate, if the problem is acute, but you risk losing a secure airway)airway)

Cuff leak, deflation, or rupture (in this case airway resistance Cuff leak, deflation, or rupture (in this case airway resistance usually drops suddenly, but the air leak is usually obvious)usually drops suddenly, but the air leak is usually obvious)

Increased resistance from heat, moisture exchanger, or in line Increased resistance from heat, moisture exchanger, or in line CO2 monitor ( removing the patient from the ventilator and CO2 monitor ( removing the patient from the ventilator and bagging should indicate it is a ventilator circuit problem)bagging should indicate it is a ventilator circuit problem)


Airway Problems: If it is not the tube, the Airway Problems: If it is not the tube, the patient is the one with the problem.patient is the one with the problem.

Bronchospasm: (remember the Bronchospasm: (remember the stethoscope?)stethoscope?)

The lower airway is occluded with The lower airway is occluded with secretions, blood, or a foreign body (OK, secretions, blood, or a foreign body (OK, go ahead and call us for bronchoscopy go ahead and call us for bronchoscopy [{damn it!}])[{damn it!}])


Pulmonary parenchymal problems:Pulmonary parenchymal problems:

ET tube has migrated into the right ET tube has migrated into the right mainstem. (Oh, wait, there is that mainstem. (Oh, wait, there is that stethoscope again, and when that “fails” stethoscope again, and when that “fails” there is always a chest xray) (Oops, it the there is always a chest xray) (Oops, it the tube again, stupid!)tube again, stupid!)

OK, the tube is really OK, it’s the patient OK, the tube is really OK, it’s the patient that really has the problemthat really has the problem


True pulmonary parenchymal problems:True pulmonary parenchymal problems:

PneumoniaPneumonia

AtalectasisAtalectasis

Pulmonary edema (cardiogenic or non-Pulmonary edema (cardiogenic or non-cardiogenic)cardiogenic)

AspirationAspiration

Pulmonary EmbolismPulmonary Embolism


““Extrapulmonary Problems”:Extrapulmonary Problems”:Pneumothorax: (suspect with acute changes in Pneumothorax: (suspect with acute changes in oxygen saturation, and airway and plateau oxygen saturation, and airway and plateau pressures) (back to the stethoscope and chest pressures) (back to the stethoscope and chest xray again)xray again)Pleural effusionPleural effusionAbdominal distension: ascites, gastic distension, Abdominal distension: ascites, gastic distension, ileus, pancreatitis, obesity, etc.ileus, pancreatitis, obesity, etc.Delirium, pain, anxiety, fever, acute CNS event, Delirium, pain, anxiety, fever, acute CNS event, acidosis (increased respiratory drive)acidosis (increased respiratory drive)

Respiratory distress on the Respiratory distress on the Ventilator: ParalysisVentilator: Paralysis

Paralysis is Paralysis is notnot the same, or part of, sedation! the same, or part of, sedation!If you need paralysis to control agitation times If you need paralysis to control agitation times one, until other measures, (e.g. propofol) can one, until other measures, (e.g. propofol) can work, OK. work, OK. If you think paralysis is required to maintain If you think paralysis is required to maintain ongoing ventilatory support, you need to be ongoing ventilatory support, you need to be calling us. Paralysis to maintain ventilation is a calling us. Paralysis to maintain ventilation is a lastlast resort!resort!Paralysis (as opposed to sedation) is usually Paralysis (as opposed to sedation) is usually onlyonly required in ARDS (and maybe severe required in ARDS (and maybe severe asthma), where chest wall relaxation is required asthma), where chest wall relaxation is required to reduce inspiratory pressures. (my opinion)to reduce inspiratory pressures. (my opinion)

Respiratory Distress on the Respiratory Distress on the Ventilator: ParalysisVentilator: Paralysis

Be sure you know the patient’s ABG, ventilator Be sure you know the patient’s ABG, ventilator settings, and minute ventilation first!settings, and minute ventilation first!

Do not paralyze for agitation on an IMV of 2 bpm Do not paralyze for agitation on an IMV of 2 bpm

Do not paralyze for tachypnea with a pH of 7.00, Do not paralyze for tachypnea with a pH of 7.00, a pCO2 of 10, and a minute ventilation of 25 a pCO2 of 10, and a minute ventilation of 25 L/min in order to start or continue ventilator L/min in order to start or continue ventilator settings delivering a minute ventilation of 10 settings delivering a minute ventilation of 10 L/minL/min

… …you might need a pulmonologistyou might need a pulmonologist

I do not think I can ventilate this patient I do not think I can ventilate this patient unless I keep them paralyzed…unless I keep them paralyzed…The patient is asthmatic (or has COPD) The patient is asthmatic (or has COPD) with high airway pressures and inability to with high airway pressures and inability to ventilate (may need “permissive ventilate (may need “permissive hypercapnea”)…hypercapnea”)…You always use volume controlled You always use volume controlled ventilation, its not working, and and RT is ventilation, its not working, and and RT is suggesting possible PCV….suggesting possible PCV….


The patient is on the ventilator and you The patient is on the ventilator and you can not achieve adequate oxygenation…can not achieve adequate oxygenation…There is a problem with the endotracheal There is a problem with the endotracheal tube …tube …You think the patient is developing ARDS You think the patient is developing ARDS and airway pressures are high and and airway pressures are high and oxygenation is low…oxygenation is low…The patient is hemodynamically unstable, The patient is hemodynamically unstable, and is not responding to IV fluids …and is not responding to IV fluids …


I could go on (and on, and on, and on …), I could go on (and on, and on, and on …), but you get the ideabut you get the idea

We need (and love) our sleep, but if in We need (and love) our sleep, but if in doubt call us.doubt call us.

Thank you!Thank you!

Health & Medicine

Oxygenation, Ventilation And Ventilator Management In The First 24 Hours