copyright © 2006 by mosby, inc. slide 1 chapter 45 respiratory failure

Copyright © 2006 by Mosby, Inc.Slide 1

Chapter 45Chapter 45Respiratory FailureRespiratory Failure


Mechanical VentilationMechanical Ventilation

Mechanical ventilation may be delivered by:Mechanical ventilation may be delivered by: Endotracheal tube (most common)Endotracheal tube (most common)

Tracheostomy Tracheostomy

Face mask Face mask

Cuirass-type deviceCuirass-type device



Ventilator modes include:Ventilator modes include: Assist-control (A/C)Assist-control (A/C)

Synchronized intermittent mandatory ventilation Synchronized intermittent mandatory ventilation (SIMV)(SIMV)

• With or without pressure support (PS)With or without pressure support (PS)

Less commonly used modes include:Less commonly used modes include:

• SIMV aloneSIMV alone

• Inverse-rate ventilation (IRV)Inverse-rate ventilation (IRV)

• Airway pressure release ventilation (APRV)Airway pressure release ventilation (APRV)



The goal of mechanical ventilation is to totally The goal of mechanical ventilation is to totally or partially replace the gas exchange function or partially replace the gas exchange function of the lungs—with as few complications as of the lungs—with as few complications as possiblepossible



The objectives of mechanical ventilation The objectives of mechanical ventilation are to:are to: Improve and maintain alveolar ventilationImprove and maintain alveolar ventilation

To ensure adequate COTo ensure adequate CO22 and pH homeostasis, and pH homeostasis, oxygenation, and lung inflation oxygenation, and lung inflation

To reduce the work of breathingTo reduce the work of breathing



Achievement of these objectivesAchievement of these objectives Reverses acute respiratory acidosis with hypoxemiaReverses acute respiratory acidosis with hypoxemia

• Also called acute ventilatory failure with hypoxemiaAlso called acute ventilatory failure with hypoxemia

Relieves patient discomfortRelieves patient discomfort

Reverses or prevents atelectasisReverses or prevents atelectasis

Reverses muscle fatigueReverses muscle fatigue

Stabilizes the chest wallStabilizes the chest wall

Allows sedation and/or neuromuscular blockadeAllows sedation and/or neuromuscular blockade

Decreases systemic or myocardial oxygen Decreases systemic or myocardial oxygen consumptionconsumption


Etiology and PathogenesisEtiology and Pathogenesis

Four conditions that commonly require Four conditions that commonly require mechanical ventilationmechanical ventilation Acute respiratory failure (ARF)—74%Acute respiratory failure (ARF)—74%

• Also called acute ventilatory failure (AVF)Also called acute ventilatory failure (AVF)

Exacerbation of chronic obstructive pulmonary Exacerbation of chronic obstructive pulmonary disease (COPD)—16%disease (COPD)—16%

Coma—7%Coma—7%

Neuromuscular disease—3%Neuromuscular disease—3%



The causes of ARF include the following:The causes of ARF include the following: Postoperative complicationsPostoperative complications

Sepsis Sepsis

TraumaTrauma

PneumoniaPneumonia

Heart failureHeart failure

ARDSARDS

AspirationAspiration

Others (miscellaneous)Others (miscellaneous)



All of the clinical scenarios described in All of the clinical scenarios described in Chapter 9 may (and do, if left untreated) lead Chapter 9 may (and do, if left untreated) lead to respiratory failureto respiratory failure

It is crucial that the RCP be able to recognize It is crucial that the RCP be able to recognize the clinical scenarios caused by:the clinical scenarios caused by: The six most common anatomic alterations of the The six most common anatomic alterations of the

lungs (see Chapter 9), andlungs (see Chapter 9), and

The respiratory disorders that produce them (see The respiratory disorders that produce them (see Table 45-1) page 540Table 45-1) page 540


Figure 9-8. Alveolar consolidation clinical scenario.Figure 9-8. Alveolar consolidation clinical scenario.


Figure 9-9. Increased alveolar-capillary membrane thickness clinical scenario. Figure 9-9. Increased alveolar-capillary membrane thickness clinical scenario.


Figure 9-10. Bronchospasm clinical scenario (e.g., asthma). Figure 9-10. Bronchospasm clinical scenario (e.g., asthma).


Figure 9-11. Excessive bronchial secretions clinical scenario.Figure 9-11. Excessive bronchial secretions clinical scenario.


Figure 9-12. Distal airway and alveolar weakening clinical scenario.Figure 9-12. Distal airway and alveolar weakening clinical scenario.


Box 45-1. Conditions That May Develop in the Box 45-1. Conditions That May Develop in the Hospital and Complicate the Management of Hospital and Complicate the Management of

Patients Receiving Mechanical VentilationPatients Receiving Mechanical VentilationCC Cardiovascular eventsCardiovascular eventsAA Acute respiratory distress syndromeAcute respiratory distress syndromePP Pulmonary embolism/infarctionPulmonary embolism/infarction

PP PneumothoraxPneumothoraxNN Neuropsychiatric complicationsNeuropsychiatric complicationsEE Electrolyte and fluid imbalanceElectrolyte and fluid imbalanceUU Upper airway obstructionUpper airway obstructionMM MalnutritionMalnutritionOO Oxygen toxicityOxygen toxicityNN Nonsense dataNonsense dataII InfectionInfectionAA AtelectasisAtelectasis


Table 45-1. Table 45-1.


Table 45-1., cont.Table 45-1., cont.


Overview of the Cardiopulmonary Clinical Overview of the Cardiopulmonary Clinical Manifestations Associated withManifestations Associated with

ACUTE RESPIRATORY FAILUREACUTE RESPIRATORY FAILURE At the right side of each of the clinical At the right side of each of the clinical

scenarios (see Figures 9-7 though 9-12) is an scenarios (see Figures 9-7 though 9-12) is an overview of the signs and symptoms of the overview of the signs and symptoms of the various diseases that, when allowed to various diseases that, when allowed to proceed to their “worst case scenario,” end in proceed to their “worst case scenario,” end in acute respiratory failureacute respiratory failure

The following are clinical manifestations of The following are clinical manifestations of acute respiratory failure that are indications acute respiratory failure that are indications for mechanical ventilationfor mechanical ventilation


Clinical Manifestations ofClinical Manifestations ofAcute Respiratory FailureAcute Respiratory Failure

Somnolence proceeding to comaSomnolence proceeding to coma An indication of alveolar hypoventilationAn indication of alveolar hypoventilation

Severe and worsening hypoxemiaSevere and worsening hypoxemia

Excessive work of breathingExcessive work of breathing

Inadequate lung expansionInadequate lung expansion


Clinical IndicatorsClinical Indicators

Respiratory acidosis (acute ventilatory failure)Respiratory acidosis (acute ventilatory failure)

PaPaCOCO22, , pH, pH, PaO PaO22, , Sp SpOO22

Agitation, tachycardia, pulse >120, A-aOAgitation, tachycardia, pulse >120, A-aO22, ,

Pa PaOO22/FI/FIOO22, , shunt fraction, venous shunt fraction, venous

admixtureadmixture


Clinical IndicatorsClinical Indicators

Dyspnea, Dyspnea, ventilatory effect, ventilatory effect, physiologic physiologic dead space, dead space, respiratory rate, diaphoresis, respiratory rate, diaphoresis, use of accessory muscles, abdominal paradoxuse of accessory muscles, abdominal paradox

Atelectasis, Atelectasis, ventilatory capacity, ventilatory capacity, maximum maximum inspiratory pressure, inspiratory pressure, maximum voluntary maximum voluntary ventilationventilation


The Fifth Protocol—The Fifth Protocol—General ManagementGeneral Management

Do any contraindications to invasive Do any contraindications to invasive mechanical ventilation exist?mechanical ventilation exist? Patient’s wishes to the contraryPatient’s wishes to the contrary

Needless prolongation of the patient’s lifeNeedless prolongation of the patient’s life


Ventilator Management and Ventilator Management and Ventilator Weaning ModesVentilator Weaning Modes

More than 90% of patients requiring More than 90% of patients requiring ventilatory support in the United States are ventilatory support in the United States are ventilated with assist/control aloneventilated with assist/control alone Or in combination with PS ventilationOr in combination with PS ventilation

Initial tidal volume (VInitial tidal volume (VTT) settings) settings 6 to 10 ml/kg ideal body weight6 to 10 ml/kg ideal body weight

5 to 6 ml/kg for recent “lung protective strategies”5 to 6 ml/kg for recent “lung protective strategies”



In routine cases, 10 to 12 ml/kg is used In routine cases, 10 to 12 ml/kg is used routinelyroutinely

Tidal volumes as great as 16 ml/kg have Tidal volumes as great as 16 ml/kg have been used to minimize atelectasis in acute been used to minimize atelectasis in acute neuromuscular diseasesneuromuscular diseases

And initial PEEP setting of 5 cm HAnd initial PEEP setting of 5 cm H22O is used O is used in most casesin most cases However, PEEP should not be used in patients However, PEEP should not be used in patients

with acute brain injury, and cautiously in COPD with acute brain injury, and cautiously in COPD patientspatients



Except in patients with anoxic brain or Except in patients with anoxic brain or myocardial injuries, permissive hypercapnia myocardial injuries, permissive hypercapnia is allowedis allowed

VVTT and RR are adjusted to achieve the and RR are adjusted to achieve the predetermined pH and plateau pressure predetermined pH and plateau pressure goalsgoals

The inspiratory flow is set above spontaneous The inspiratory flow is set above spontaneous breathing patient demandbreathing patient demand



Use of other protocolsUse of other protocols Bronchopulmonary hygiene therapy protocolBronchopulmonary hygiene therapy protocol

Hyperinflation therapy protocolHyperinflation therapy protocol

Aerosolized medication protocolAerosolized medication protocol


Disorder: Normal Lung Mechanics —but Disorder: Normal Lung Mechanics —but Patient Has ApneaPatient Has Apnea

Disease characteristicsDisease characteristics Normal compliance and airway resistanceNormal compliance and airway resistance

Ventilator modeVentilator mode Volume ventilation in the AC or SIMV modeVolume ventilation in the AC or SIMV mode Or pressure ventilation—either PRVC or PCOr pressure ventilation—either PRVC or PC

Tidal volume and respiratory rateTidal volume and respiratory rate 10 to 12 ml/kg10 to 12 ml/kg 6 to 10 bpm6 to 10 bpm

• 6 to 10 bpm when SIMV mode is used6 to 10 bpm when SIMV mode is used

Table 9-3 Common Ventilatory Management StrategiesTable 9-3 Common Ventilatory Management Strategies


Normal Lung Mechanics, cont.Normal Lung Mechanics, cont. Flow rateFlow rate

60 to 80 L/min60 to 80 L/min

I:E ratioI:E ratio 1:21:2

FIOFIO22

Low to moderateLow to moderate

General goals and/or concernsGeneral goals and/or concerns Care to ensure plateau pressure of 30 cm HCare to ensure plateau pressure of 30 cm H22O or lessO or less

Smaller tidal volumes (<7 ml/kg) should be avoided Smaller tidal volumes (<7 ml/kg) should be avoided because atelectasis can developbecause atelectasis can develop

Table 9-3 Common Ventilatory Management Strategies, cont.Table 9-3 Common Ventilatory Management Strategies, cont.


Disorder: Chronic Obstructive Pulmonary Disorder: Chronic Obstructive Pulmonary Disease (COPD)Disease (COPD)

Disease characteristicsDisease characteristics High lung compliance and high airway resistanceHigh lung compliance and high airway resistance

Ventilator modeVentilator mode Volume ventilation in the AC or SIMV modeVolume ventilation in the AC or SIMV mode Or pressure ventilation—either PRVC or PCOr pressure ventilation—either PRVC or PC Noninvasive positive pressure ventilation (NPPV) is good Noninvasive positive pressure ventilation (NPPV) is good

alternativealternative

Tidal volume and respiratory rateTidal volume and respiratory rate Good starting point: 10 ml/kg and 10 to 12 bpmGood starting point: 10 ml/kg and 10 to 12 bpm A small tidal volume (5-8 ml/kg) and 8 to 10 bpm with A small tidal volume (5-8 ml/kg) and 8 to 10 bpm with

increased flow rates to allow adequate expiratory timeincreased flow rates to allow adequate expiratory time



COPD, cont.COPD, cont. Flow rateFlow rate

60 L/min60 L/min I:E ratioI:E ratio

1:2 or 1:31:2 or 1:3 FIOFIO22

Low to moderateLow to moderate General goals and/or concernsGeneral goals and/or concerns

Air-trapping and auto-PEEP can occur when Air-trapping and auto-PEEP can occur when expiratory time is too shortexpiratory time is too short

↑ ↑ Expiratory time to offset auto-PEEPExpiratory time to offset auto-PEEP May ↑ inspiratory flow up to 100 L/min to ↑ expiratory timeMay ↑ inspiratory flow up to 100 L/min to ↑ expiratory time May ↓ VMay ↓ VTT or rate to ↑ expiratory time or rate to ↑ expiratory time Do not overventilate COPD patients with chronically Do not overventilate COPD patients with chronically

high Pahigh PaCOCO22 levels levels



Disorder: Acute Asthmatic EpisodeDisorder: Acute Asthmatic Episode

Disease characteristicsDisease characteristics High airway resistanceHigh airway resistance

Ventilator modeVentilator mode SIMV mode is recommended—to offset air-trappingSIMV mode is recommended—to offset air-trapping

Tidal volume and respiratory rateTidal volume and respiratory rate Good starting point: 8 to 10 ml/kg Good starting point: 8 to 10 ml/kg

Rate of 10 to 12 bpmRate of 10 to 12 bpm

When air-trapping is extensive, a lower tidal volumeWhen air-trapping is extensive, a lower tidal volume(5-6 ml/kg) and slower rate may be required(5-6 ml/kg) and slower rate may be required



Acute Asthmatic Episode, cont.Acute Asthmatic Episode, cont. Flow rateFlow rate

60 L/min60 L/min

I:E ratioI:E ratio

1:2 or 1:31:2 or 1:3

FIOFIO22

Start at 100% and titrate downward per SpOStart at 100% and titrate downward per SpO22 and ABGs and ABGs

General goals and/or concernsGeneral goals and/or concerns In severe cases, the development of auto-PEEP may In severe cases, the development of auto-PEEP may

be inevitable be inevitable

With controlled ventilation, a small amount of PEEP to offset auto-With controlled ventilation, a small amount of PEEP to offset auto-PEEP may be cautiously appliedPEEP may be cautiously applied



Disorder: Acute Respiratory Distress SyndromeDisorder: Acute Respiratory Distress Syndrome

Disease characteristicsDisease characteristics Diffuse, uneven alveolar injuryDiffuse, uneven alveolar injury

Ventilator modeVentilator mode Volume ventilation in the AC or SIMV modeVolume ventilation in the AC or SIMV mode

Or pressure ventilation—PRVC or PCOr pressure ventilation—PRVC or PC

Tidal volume and respiratory rateTidal volume and respiratory rate Typically started at low tidal volumes and higher ratesTypically started at low tidal volumes and higher rates

• 8 ml/kg and adjusted downward to 6 ml/kg or 4 ml/kg8 ml/kg and adjusted downward to 6 ml/kg or 4 ml/kg

• Respiratory rate as high as 35 bpmRespiratory rate as high as 35 bpm



Acute Respiratory Distress Syndrome, Cont.Acute Respiratory Distress Syndrome, Cont. Flow rateFlow rate

60 to 80 L/min60 to 80 L/min I:E ratioI:E ratio

1:1 or 1:21:1 or 1:2 Do what is necessary to meet a rapid respiratory rateDo what is necessary to meet a rapid respiratory rate

FIOFIO22

Less than 0.6 if possibleLess than 0.6 if possible General goals and/or concernsGeneral goals and/or concerns

Goal is to limit transpulmonary pressuresGoal is to limit transpulmonary pressures 30 cm H30 cm H22O of less if possibleO of less if possible PEEP is usually needed to prevent atelectasisPEEP is usually needed to prevent atelectasis Permissive hypercapnia may be allowed Permissive hypercapnia may be allowed



Disorder: Postoperative Ventilatory SupportDisorder: Postoperative Ventilatory Support Disease characteristicsDisease characteristics

Often normal compliance and airway resistanceOften normal compliance and airway resistance

Ventilator modeVentilator mode SIMV with pressure support SIMV with pressure support Or AC volume ventilationOr AC volume ventilation Or pressure ventilation—either PRVC or PCOr pressure ventilation—either PRVC or PC

Tidal volume and respiratory rateTidal volume and respiratory rate Good starting point: 10 to 12 ml/kgGood starting point: 10 to 12 ml/kg Rate of 10 to 12 bpmRate of 10 to 12 bpm

• However, larger tidal volumes (12-15 ml/kg) and slower rates (6-10 However, larger tidal volumes (12-15 ml/kg) and slower rates (6-10 bpm) may be used to maintain lung volumebpm) may be used to maintain lung volume



Postoperative Ventilatory Support, Cont.Postoperative Ventilatory Support, Cont. Flow rateFlow rate

60 L/min60 L/min


FIOFIO22


General goals and/or concernsGeneral goals and/or concerns PEEP or CPAP of 3 to 5 cm HPEEP or CPAP of 3 to 5 cm H22O may be applied to O may be applied to

offset atelectasisoffset atelectasis



Disorder: Neuromuscular DisorderDisorder: Neuromuscular Disorder

Disease characteristicsDisease characteristics Normal compliance and airway resistanceNormal compliance and airway resistance

Ventilator modeVentilator mode Volume ventilation in the AC or SIMV modeVolume ventilation in the AC or SIMV mode

Or pressure ventilation—either PRVC or PCOr pressure ventilation—either PRVC or PC

Tidal volume and respiratory rateTidal volume and respiratory rate Good starting point: 12 to 15 ml/kgGood starting point: 12 to 15 ml/kg

Rate of 10 to 12 bpmRate of 10 to 12 bpm



Neuromuscular Disorder, cont.Neuromuscular Disorder, cont.

Flow rateFlow rate 60 L/min60 L/min


FIOFIO22


General goals and/or concernsGeneral goals and/or concerns PEEP of 3 to 5 cm HPEEP of 3 to 5 cm H22O may be applied to offset O may be applied to offset

atelectasisatelectasis



Classroom DiscussionClassroom DiscussionCase Study: Case Study:

Acute Respiratory FailureAcute Respiratory Failure

copyright © 2006 by mosby, inc. slide 1 chapter 45 respiratory failure

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