Respiratory Talk

Essentials of Essentials of Respiratory CareRespiratory Care

Paul Barraza RRT, RCPPaul Barraza RRT, RCPEducation Coordinator, Santa Clara Valley Medical Education Coordinator, Santa Clara Valley Medical

CenterCenter

Adjunct Faculty, Department of Biological Sciences, Adjunct Faculty, Department of Biological Sciences, Foothill CollegeFoothill College

ContentsContents Anatomy and Physiology of the Anatomy and Physiology of the

Respiratory SystemRespiratory System– Function of Respiratory SystemFunction of Respiratory System– Upper vs. Lower AirwayUpper vs. Lower Airway– Cellular Properties of the AlveolusCellular Properties of the Alveolus– Ventilation / RespirationVentilation / Respiration– Diffusion / PerfusionDiffusion / Perfusion

Basics of Acid-Base ImbalancesBasics of Acid-Base Imbalances

Arterial Blood Gas InterpretationArterial Blood Gas Interpretation

ContentsContents Mechanical VentilationMechanical Ventilation

– IndicationsIndications– GoalsGoals– MonitoringMonitoring– Basics of ventilationBasics of ventilation

Sedatives, Analgesics, and ParalyticsSedatives, Analgesics, and Paralytics Disease Specific ManagementDisease Specific Management

– PneumoniaPneumonia– Pulmonary EmbolusPulmonary Embolus– Chest TraumaChest Trauma– ARDSARDS

Anatomy and PhysiologyAnatomy and Physiology

Function Function

Primary function of the respiratory Primary function of the respiratory system is the continuous absorption system is the continuous absorption of Oof O22 and the excretion of CO and the excretion of CO22

– External RespirationExternal Respiration The exchange of gas from the atmosphere The exchange of gas from the atmosphere

and the bloodand the blood

– Internal RespirationInternal Respiration The exchange of gases between blood and The exchange of gases between blood and

the tissuesthe tissues

Upper vs. Lower Respiratory Upper vs. Lower Respiratory TractTract

Upper Respiratory TractUpper Respiratory Tract– All structures starting at the mouth or All structures starting at the mouth or

nose and extending down to the tracheanose and extending down to the trachea NoseNose

– Vestibule (hairs act as gross filter)Vestibule (hairs act as gross filter)– Concha (turbinates increase surface area of nose Concha (turbinates increase surface area of nose

to aid in filtration and humidification)to aid in filtration and humidification)

Oral CavityOral Cavity– Soft palate and uvula (control flow of air, fluid and Soft palate and uvula (control flow of air, fluid and

food during eating, drinking, sneezing and food during eating, drinking, sneezing and coughing)coughing)

Upper Respiratory Tract Cont.Upper Respiratory Tract Cont.– PharynxPharynx

Subdivided into:Subdivided into:– NasopharynxNasopharynx– OropharynxOropharynx– HypopharynxHypopharynx– LarynopharynxLarynopharynx

Primary function is to aid in filtration and in Primary function is to aid in filtration and in speechspeech


Upper Respiratory Tract Cont.Upper Respiratory Tract Cont.– LarynxLarynx

Formed by cartilage and muscleFormed by cartilage and muscle– ThyroidThyroid– CricoidCricoid– EpiglottisEpiglottis– Vocal CordsVocal Cords

Primary functionPrimary function– Protect the respiratory tract during eating and Protect the respiratory tract during eating and

drinkingdrinking– PhonationPhonation


Lower Respiratory TractLower Respiratory Tract– Conducting AirwaysConducting Airways

TracheaTrachea Right & Left Main BronchiRight & Left Main Bronchi LobarLobar SegmentalSegmental SubsegmentalSubsegmental BronchiBronchi Terminal bronchiTerminal bronchi Bronchioles (No cartilage)Bronchioles (No cartilage) Terminal Bronchioles (No cartilage)Terminal Bronchioles (No cartilage)

– Primary FunctionPrimary Function Airway conductionAirway conduction


Lower Respiratory TractLower Respiratory Tract– Respiratory AirwaysRespiratory Airways

Respiratory BronchiolesRespiratory Bronchioles Terminal Respiratory BronchiolesTerminal Respiratory Bronchioles Alveolar Ducts/SacsAlveolar Ducts/Sacs AlveoliAlveoli

– Primary FunctionPrimary Function Gas exchangeGas exchange


Estimates range from 270 to 790 Estimates range from 270 to 790 millionmillion

Average 480 millionAverage 480 million Number increase with height of subjectNumber increase with height of subject Average 0.2mm in diameter when at Average 0.2mm in diameter when at

FRCFRC Larger in apecies than in bases due to Larger in apecies than in bases due to

organ weightorgan weight

AlveoliAlveoli

Type I pneumocytes (extremely flat Type I pneumocytes (extremely flat squamous epithelia)squamous epithelia)– Covers 93% of alveolar surfaceCovers 93% of alveolar surface– Create patchwork like surface over the Create patchwork like surface over the

alveolar capillaries forming the gas alveolar capillaries forming the gas exchange surface of the alveolusexchange surface of the alveolus

Type II pneumocytes (cuboidal Type II pneumocytes (cuboidal epithelia)epithelia)– Cover 7% of the alveolar surfaceCover 7% of the alveolar surface– Manufacture surfactant and secretes it Manufacture surfactant and secretes it

onto the alveolar surfaceonto the alveolar surface

AlveoliAlveoli

MacrophagesMacrophages– Defensive cell that patrol alveolar region Defensive cell that patrol alveolar region

and phagocytize foreign particles and and phagocytize foreign particles and cells (bacteria)cells (bacteria)

Canals of LambertCanals of Lambert– Small openings that connect the alveoli to Small openings that connect the alveoli to

the respiratory bronchiolesthe respiratory bronchioles Pores of KohnPores of Kohn

– Small openings in the alveolar septa that Small openings in the alveolar septa that allow gas to flow from one alveolus to allow gas to flow from one alveolus to anotheranother

AlveoliAlveoli

Alveolar Capillary Alveolar Capillary MembraneMembrane

Surfactant Layer (outermost layer)Surfactant Layer (outermost layer) Type I cellType I cell Interstitial SpaceInterstitial Space

– Basement membranesBasement membranes– Matrix material connective tissue fibersMatrix material connective tissue fibers

Alveolar capillaryAlveolar capillary– PlasmaPlasma– ErythrocytesErythrocytes

Alveolar Capillary Alveolar Capillary MembraneMembrane

Ventilation vs. RespirationVentilation vs. Respiration

VentilationVentilation– The process of moving gas into and out The process of moving gas into and out

of the lungsof the lungs

RespirationRespiration– The process of getting oxygen into the The process of getting oxygen into the

body for tissue utilization and removal body for tissue utilization and removal of carbon dioxide into the atmosphereof carbon dioxide into the atmosphere

Diffusion/PerfusionDiffusion/Perfusion

The process whereby molecules move The process whereby molecules move from areas of high concentration to from areas of high concentration to areas of low concentrationareas of low concentration– Driven by kinetic energyDriven by kinetic energy

Gases have high kinetic energyGases have high kinetic energy

– Lighter gases diffuse more rapidly than Lighter gases diffuse more rapidly than heavy gasesheavy gases

– Increasing kinetic energy will increase Increasing kinetic energy will increase diffusiondiffusion HeatHeat Mechanical agitationMechanical agitation

Diffusion/PerfusionDiffusion/Perfusion

OO22 & CO & CO22 move between the lungs move between the lungs and the tissue via diffusionand the tissue via diffusion

OxygenOxygen– POPO2 2 ~ 159mmHg in atmosphere~ 159mmHg in atmosphere

– POPO22 ~ 40mmHg in capillaries ~ 40mmHg in capillaries

Carbon DioxideCarbon Dioxide– PCOPCO22 ~ 60mmHg in the cells ~ 60mmHg in the cells

– PCOPCO22 ~ 1mmHg in room air ~ 1mmHg in room air

Barriers to Barriers to Diffusion/PerfusionDiffusion/Perfusion

Alveolar Capillary MembraneAlveolar Capillary Membrane– Alveolar epitheliumAlveolar epithelium– Interstitial spaceInterstitial space– Capillary endotheliumCapillary endothelium

Erythrocyte MembraneErythrocyte Membrane

Diffusion/Perfusion Diffusion/Perfusion ImpairmentImpairment

Interstitial lung Disease (thickening Interstitial lung Disease (thickening of interstitiumof interstitium– Pulmonary FibrosisPulmonary Fibrosis– AsbestosisAsbestosis– SarcoidosisSarcoidosis

Emphysema (destruction of alveoli)Emphysema (destruction of alveoli) Pulmonary Vascular AbnormalitiesPulmonary Vascular Abnormalities

– Pulmonary hypertensionPulmonary hypertension– Pulmonary embolusPulmonary embolus

Ventilation/Perfusion Ventilation/Perfusion MismatchMismatch

Dead space (physiologic)Dead space (physiologic)– Areas ventilated but not perfusedAreas ventilated but not perfused– Anatomic dead spaceAnatomic dead space

The volume of the conducting airways ~ The volume of the conducting airways ~ 1ml/lb1ml/lb

– Alveolar dead spaceAlveolar dead space The volume of gas ventilating unperfused The volume of gas ventilating unperfused

alveolialveoli

ShuntShunt– Areas perfused but not ventilatedAreas perfused but not ventilated

Ventilation/Perfusion Ventilation/Perfusion MismatchMismatch

Basics of Acid-Base Basics of Acid-Base ImbalancesImbalances

Terminology Terminology AcidAcid: A substance that donates hydrogen ions: A substance that donates hydrogen ions BaseBase: A substance that accepts hydrogen ions: A substance that accepts hydrogen ions AcidemiaAcidemia: a condition of blood pH of less than : a condition of blood pH of less than

7.357.35 AlkalemiaAlkalemia: a condition of blood pH of greater : a condition of blood pH of greater

than 7.45than 7.45 AcidosisAcidosis: is the process of causing acidemia: is the process of causing acidemia AlkalosisAlkalosis: is the process of casing alkalemia: is the process of casing alkalemia CorrectionCorrection: is the process in which the system : is the process in which the system

that was not properly functioning is repaired and that was not properly functioning is repaired and hereby returns the pH toward the normal rangehereby returns the pH toward the normal range

TerminologyTerminology CompensationCompensation: is the process in which the system : is the process in which the system

that is still functioning properly is responsible for that is still functioning properly is responsible for returning the pH toward the normal range.returning the pH toward the normal range.

pHpH: power of hydrogen measures blood acidity and : power of hydrogen measures blood acidity and concentration of hydrogen ionsconcentration of hydrogen ions

PaOPaO22: tension of O: tension of O22 gas in the arterial blood gas in the arterial blood PaCOPaCO22 tension of CO tension of CO22 in the arterial blood in the arterial blood HCOHCO33

--: Blood bicarbonate. The principal buffer : Blood bicarbonate. The principal buffer against drastic changes in against drastic changes in pH that would occur pH that would occur with changes in PaCOwith changes in PaCO22. It is an indicator of . It is an indicator of metabolic/ kidney function.metabolic/ kidney function.

BufferBuffer: is a substance that resists change in H+ : is a substance that resists change in H+ concentration upon addition of a strong acid or baseconcentration upon addition of a strong acid or base

Normal Adult Blood Gas Normal Adult Blood Gas Values at Sea LevelValues at Sea Level

ArterialArterial VenousVenous

pHpH 7.40 (7.35-7.45)7.40 (7.35-7.45) 7.36 (7.31-7.41)7.36 (7.31-7.41)

PaOPaO22 80-100 mmHg80-100 mmHg 35-40 mmHg35-40 mmHg

PaCOPaCO22 40 mmHg (35-40 mmHg (35-

45)45)41-51 mmHg41-51 mmHg

SaOSaO22 95% or better95% or better 70-75%70-75%

HCOHCO33

-- 24 mEq/L 24 mEq/L ++ 2 2 24 mEq/L 24 mEq/L ++ 2 2

B.E.B.E. 0 0 ++ 2 2 0 0 ++ 2 2

Causes of Respiratory Causes of Respiratory AcidosisAcidosis

With normal lungsWith normal lungs– CNS depression--sedatives, CNS disease, CNS depression--sedatives, CNS disease,

obesity, hypoventilationobesity, hypoventilation– Neuromuscular diseaseNeuromuscular disease– TraumaTrauma– Severe restrictive disordersSevere restrictive disorders

With abnormal lungsWith abnormal lungs– COPDCOPD– Pneumonia Pneumonia – Pleural disease (pneumothorax)Pleural disease (pneumothorax)– Acute airway obstruction (asthma exacerbation)Acute airway obstruction (asthma exacerbation)

Signs & Symptoms of Signs & Symptoms of Respiratory AcidosisRespiratory Acidosis

TachypneaTachypnea HeadacheHeadache ConfusionConfusion DrowsinessDrowsiness ComaComa DysrhythmiasDysrhythmias

Causes of Respiratory Causes of Respiratory AlkalosisAlkalosis

With normal lungs With normal lungs With abnormal lungsWith abnormal lungs

AnxietyAnxiety Usually a respiratoryUsually a respiratory

Fever Fever response to hypoxia response to hypoxia

Stimulant drugsStimulant drugs Acute asthma Acute asthma exacerbation exacerbation

CNS lesion/trauma CNS lesion/trauma Pneumonia Pneumonia

Pain Pain Pulmonary edemaPulmonary edema

SepsisSepsis

High altitudeHigh altitude

Signs & Symptoms of Signs & Symptoms of Respiratory AlkalosisRespiratory Alkalosis

DizzinessDizziness Numbness & TinglingNumbness & Tingling Muscular weaknessMuscular weakness TwitchingTwitching Irregular heart rhythmIrregular heart rhythm

Causes of Metabolic AcidosisCauses of Metabolic Acidosis

Lactic acidosis (hypoxia)Lactic acidosis (hypoxia) Keto acidosis (diabetes)Keto acidosis (diabetes) Ingestion of base depleting drugsIngestion of base depleting drugs

– AspirinAspirin– AlcoholAlcohol

Renal failureRenal failure DiarrheaDiarrhea

Causes of Metabolic Causes of Metabolic AlkalosisAlkalosis

Excessive administration of steroidsExcessive administration of steroids– (K+depletion---incr. HCO3- reabsorption)(K+depletion---incr. HCO3- reabsorption)

Gastric suctioning/vomitingGastric suctioning/vomiting Hypochloremia (usually from Hypochloremia (usually from

vomiting)vomiting) HypokalemiaHypokalemia

– Several days of IV therapy w/o adequate Several days of IV therapy w/o adequate replacement of K+, diuretic therapy, diarrhea)replacement of K+, diuretic therapy, diarrhea)

Excessive administration /ingestion Excessive administration /ingestion of HCOof HCO33

-- (licorice) (licorice)

Acid-Base Disorders and Acid-Base Disorders and Parameter ChangesParameter Changes

pHpH PCOPCO22 HCOHCO

33-- KK++ ClCl--

Respiratory AcidemiaRespiratory Acidemia (ventilatory failure)(ventilatory failure)

acuteacute NN NN NN

chronicchronic NN NN

Respiratory AlkalemiaRespiratory Alkalemia (alveolar (alveolar

hyperventilation)hyperventilation)

acuteacute NN NN NN

chronicchronic NN



33-- KK++ ClCl--

Metabolic AcidemiaMetabolic Acidemia

acuteacute NN

partially partially compensatedcompensated

compensatedcompensated NN NN NN

Metabolic AlkalemiaMetabolic Alkalemia

acuteacute NN

partially partially compensatedcompensated

compensatedcompensated NN NN NN



33-- KK++ ClCl--

Combined Respiratory and Combined Respiratory and Metabolic AcidemiaMetabolic Acidemia

Combined Respiratory and Combined Respiratory and Metabolic AlkalemiaMetabolic Alkalemia

Compensatory Mechanisms for Compensatory Mechanisms for Acid - Base ImbalancesAcid - Base Imbalances

Respiratory AcidosisRespiratory Acidosis– Kidneys restore pH by reabsorbing HCOKidneys restore pH by reabsorbing HCO33

-- into the bloodinto the blood

Respiratory AlkalosisRespiratory Alkalosis– Kidneys restore pH by urinary Kidneys restore pH by urinary

elimination of HCOelimination of HCO33--


Metabolic AcidosisMetabolic Acidosis– The lungs restore the pH by eliminating The lungs restore the pH by eliminating

CO2CO2

Metabolic AlkalosisMetabolic Alkalosis– The lungs restore the pH by retaining CO2The lungs restore the pH by retaining CO2


Lungs compensate quickly for Lungs compensate quickly for metabolic acid-base abnormalities metabolic acid-base abnormalities because ventilation can change the because ventilation can change the COCO22 within seconds within seconds

Kidneys require more time to retain Kidneys require more time to retain or excrete HCOor excrete HCO33

-- therefore therefore compensation is much slowercompensation is much slower

PaOPaO22

Varies with ageVaries with age

Normal PaONormal PaO22 = 104 - (0.3 x age) = 104 - (0.3 x age)

HypoxemiaHypoxemia

NormalNormal PaOPaO22 80 - 100 mmHg80 - 100 mmHg

Mild hypoxemiaMild hypoxemia PaO PaO22 60-79 mmHg 60-79 mmHg

Moderate hypoxemiaModerate hypoxemia PaO PaO22 40-59 mmHg 40-59 mmHg

Severe hypoxemiaSevere hypoxemia PaO PaO22 <40 mmHg <40 mmHg

Arterial Blood Gas Arterial Blood Gas InterpretationInterpretation

Steps for InterpretationSteps for Interpretation

Step 1: Acidemic or AlkalemicStep 1: Acidemic or Alkalemic

Step 2: Is the primary disturbance Step 2: Is the primary disturbance respiratory or respiratory or

metabolicmetabolic

Step 3: Assess for compensationStep 3: Assess for compensation

Step 1: Acidemic or Step 1: Acidemic or AlkalemicAlkalemic

pHpH indicates the status of the body indicates the status of the body

pH > 7.45 is alkalinepH > 7.45 is alkaline

pH < 7.35 is acidpH < 7.35 is acid

The pH of the arterial blood gas measurement identifies The pH of the arterial blood gas measurement identifies the disorder as alkalemic or acidemic.the disorder as alkalemic or acidemic.

Step 1: Acidemic or Step 1: Acidemic or AlkalemicAlkalemic

Categorize pHCategorize pH

Determine whether it is:Determine whether it is:

AcidAcid BaseBase NormalNormal

7.257.25Acid_____Acid_____ Base_____ Normal___ Base_____ Normal___

Step 2: Primarily Step 2: Primarily Respiratory or MetabolicRespiratory or Metabolic

A respiratory disturbance alters the arterial A respiratory disturbance alters the arterial PaCOPaCO22 (normal value 40, range 35-45) (normal value 40, range 35-45)

– If PaCOIf PaCO22 < 35 respiratory acidosis is present < 35 respiratory acidosis is present

– If PaCOIf PaCO22 > 45, respiratory alkalosis is > 45, respiratory alkalosis is presentpresent

A metabolic disturbance alters the serum A metabolic disturbance alters the serum HCOHCO33

-- (normal value 24, range 22-26) (normal value 24, range 22-26)

– If HCOIf HCO33-- < 22, metabolic acidosis is present. < 22, metabolic acidosis is present.

– If HCOIf HCO33-- > 26, metabolic alkalosis is present > 26, metabolic alkalosis is present

PH 7.25 PH 7.25 Acid__ Base__ Normal__Acid__ Base__ Normal__

PaCOPaCO22 37 mmHg Acid__ Base__ Normal__ 37 mmHg Acid__ Base__ Normal__

HCOHCO33-- 17 mEq/l Acid__ Base__ Normal__ 17 mEq/l Acid__ Base__ Normal__

When either (or both) the lung or kidneys agree When either (or both) the lung or kidneys agree with the body it is the cause of the body’s with the body it is the cause of the body’s conditioncondition

Step 2: Primarily Step 2: Primarily Respiratory or MetabolicRespiratory or Metabolic

What if both PaCO2 & What if both PaCO2 & HCO3 are abnormal?HCO3 are abnormal?

Example: Example:

pH = 7.27 (low)pH = 7.27 (low)

PaCOPaCO22 = 27 mm Hg (low) = 27 mm Hg (low)

HCOHCO33-- = 10 mEq/L (low) = 10 mEq/L (low)

One represents the primary disorder; the other One represents the primary disorder; the other represents compensation. Which is which?represents compensation. Which is which?The value that is moving in the right abnormal The value that is moving in the right abnormal relationship is the primary problem.relationship is the primary problem.

Step 3: Assess for Step 3: Assess for CompensationCompensation

Whenever resp & metabolic conditions are in Whenever resp & metabolic conditions are in opposite directions compensation is presumed.opposite directions compensation is presumed.

When either the lungs or kidneys disagree with When either the lungs or kidneys disagree with the body it is a compensatory mechanism.the body it is a compensatory mechanism.

Compensation is complete when the pH is within Compensation is complete when the pH is within normal limits.normal limits.

Compensation is partial when the pH remains out Compensation is partial when the pH remains out of range (but closer to normal than if there was of range (but closer to normal than if there was no compensation.no compensation.

The body will never fully compensate.The body will never fully compensate.


Example 1Example 1

pH = 7.29 (low)pH = 7.29 (low)



Partially Compensated Metabolic AcidosisPartially Compensated Metabolic Acidosis


Example 2Example 2

pH = 7.36 (Normal)pH = 7.36 (Normal)



Compensated Metabolic AcidosisCompensated Metabolic Acidosis


Example 3Example 3

pH = 7.37 (Normal)pH = 7.37 (Normal)

PaCOPaCO22 = 60 mm Hg (high) = 60 mm Hg (high)

HCOHCO33-- = 30 mEq/L (high) = 30 mEq/L (high)

Compensated Respiratory AcidosisCompensated Respiratory Acidosis

Blood Gas Interpretation Blood Gas Interpretation PracticePractice

Practice 1Practice 1

pH = 7.25pH = 7.25

PaCOPaCO22 = 65 mmHg = 65 mmHg

PaOPaO22 = 55 mmHg = 55 mmHg

HCOHCO33-- = 28 mEq/L = 28 mEq/L

Respiratory Acidosis with moderate hypoxemiaRespiratory Acidosis with moderate hypoxemia



pH = 7.10pH = 7.10




Partially compensated respiratory acidosis Partially compensated respiratory acidosis with severe hypoxemiawith severe hypoxemia



pH = 7.55pH = 7.55




Uncompensated metabolic alkalosis Uncompensated metabolic alkalosis with hyperoxiawith hyperoxia

The Base ExcessThe Base Excess The amount of acid (in mmol) required The amount of acid (in mmol) required

to restore 1 litre of blood to its normal to restore 1 litre of blood to its normal pH, at a PCOpH, at a PCO22 of 40mmHg. of 40mmHg.

During the calculation any change in During the calculation any change in pH due to the PCOpH due to the PCO22 of the sample is of the sample is eliminated, therefore, the base excess eliminated, therefore, the base excess reflects only the metabolic component reflects only the metabolic component of any disturbance of acid base of any disturbance of acid base balance.balance.

The Base ExcessThe Base Excess If there is a metabolic alkalosis the base If there is a metabolic alkalosis the base

excess will be positive due to a gain of excess will be positive due to a gain of base or a loss of acid from non-respiratory base or a loss of acid from non-respiratory causescauses

However, if there is a metabolic acidosis, However, if there is a metabolic acidosis, the base excess is negative due to a loss the base excess is negative due to a loss of base or a gain of acid from non-of base or a gain of acid from non-respiratory causesrespiratory causes

Mechanical VentilationMechanical Ventilation

Iron LungIron Lung

Reasons for Mechanical Reasons for Mechanical VentilationVentilation

Respiratory Insufficiency/FailureRespiratory Insufficiency/Failure

Airway ProtectionAirway Protection

Inadequate Respiratory DriveInadequate Respiratory Drive

Surgical/ProceduralSurgical/Procedural

Respiratory Respiratory Insufficiency/FailureInsufficiency/Failure

Textbook Definition:Textbook Definition:– Respiratory activity is absent or is Respiratory activity is absent or is

insufficient to maintain adequate oxygen insufficient to maintain adequate oxygen uptake and carbon dioxide clearance uptake and carbon dioxide clearance Insufficiency – during exertionInsufficiency – during exertion Failure – at restFailure – at rest

Clinical Definition:Clinical Definition:– Inability to maintain arterial POInability to maintain arterial PO22, PCO, PCO22 and and

pH at acceptable levelspH at acceptable levels POPO22 < predicted normal for age on R/A < predicted normal for age on R/A

PCOPCO22 > 50mmHg and rising > 50mmHg and rising pH 7.25 and belowpH 7.25 and below

Signs & Symptoms of Signs & Symptoms of Respiratory Respiratory

Insufficiency/FailureInsufficiency/Failure


Indications for mechanical ventilationIndications for mechanical ventilation– ApneaApnea– Acute ventilatory failureAcute ventilatory failure– Impending acute ventilatory failureImpending acute ventilatory failure– Severe oxygenation deficitSevere oxygenation deficit


Clinical indications for mechanical Clinical indications for mechanical ventilationventilation– Primarily pulmonaryPrimarily pulmonary

ARDSARDS PneumoniaPneumonia Pulmonary EmboliPulmonary Emboli

– Mechanical abilityMechanical ability Ventilatory muscle fatigueVentilatory muscle fatigue Thoracic injury / abnormalitiesThoracic injury / abnormalities Pleural diseasesPleural diseases Neurological diseasesNeurological diseases Nutritional deficienciesNutritional deficiencies

Airway ProtectionAirway Protection

Obstruction of the airway Obstruction of the airway – SecretionSecretion– Mucosal edemaMucosal edema– BronchoconstrictionBronchoconstriction– Airway inflammationAirway inflammation– Foreign body obstructionForeign body obstruction

Inability to avoid aspirationInability to avoid aspiration– HIE (Hypoxic Ischemic Encephalopathy)HIE (Hypoxic Ischemic Encephalopathy)– Severe CNS defectsSevere CNS defects

Inadequate Respiratory Inadequate Respiratory DriveDrive

CNS disorders/injury CNS disorders/injury – HIEHIE– StrokeStroke– Structural Structural

Neuromuscular disordersNeuromuscular disorders– Amyotrophic lateral sclerosis (ALS)Amyotrophic lateral sclerosis (ALS)– Multiple sclerosis (MS)Multiple sclerosis (MS)– Muscular dystrophy (MD)Muscular dystrophy (MD)– Myasthenia gravis Myasthenia gravis – Spinal muscular atrophy (SMA)Spinal muscular atrophy (SMA)– Central Hypoventilation Syndrome AKA Central Hypoventilation Syndrome AKA

Ondyne’s CurseOndyne’s Curse

Surgical/ProceduralSurgical/Procedural

ParalysisParalysis Reduced drive due to pharmacologic Reduced drive due to pharmacologic

agentsagents– OpiatesOpiates

Cardiac or thoracic procedure Cardiac or thoracic procedure involving lung manipulationinvolving lung manipulation

Goal of Mechanical Goal of Mechanical VentilationVentilation

To provide the most appropriate To provide the most appropriate amount of support via the least amount of support via the least harmful and most comfortable harmful and most comfortable mannermanner

Goals of Mechanical Goals of Mechanical VentilationVentilation

Gently…….Gently……. Exchange of COExchange of CO22 (ventilation) and O (ventilation) and O22

(oxygenation)(oxygenation) Achieve goal pH rangeAchieve goal pH range Avoid baro/volutraumaAvoid baro/volutrauma Avoid hypo/hypercarbia, Avoid hypo/hypercarbia,

hypo/hyperoxiahypo/hyperoxia

Ventilation – Getting COVentilation – Getting CO22

OutOut Ventilation controls PaCOVentilation controls PaCO22 Determined by Minute (Alveolar) Determined by Minute (Alveolar)

Ventilation (MV) in liters/minuteVentilation (MV) in liters/minute MV – amount of gas in and out of the MV – amount of gas in and out of the

alveolialveoli MV = tidal volume (VMV = tidal volume (Vtt) x rate (RR); the ) x rate (RR); the

more gas exchange, the lower the more gas exchange, the lower the COCO22; the less gas exchanged, the ; the less gas exchanged, the higher the COhigher the CO22

Ventilation - Getting COVentilation - Getting CO22

OutOut Respiratory rate (RR) - directly setRespiratory rate (RR) - directly set Tidal volume (VTidal volume (Vtt): Goal 8-10 ml/kg): Goal 8-10 ml/kg

Can be directly set (volume ventilation) Can be directly set (volume ventilation) Or can be determined by the pressures Or can be determined by the pressures

used to ventilate (pressure ventilation)used to ventilate (pressure ventilation)

Oxygenation - Getting OOxygenation - Getting O22 In In

PaOPaO22 determined by determined by::

– FiOFiO22 – directly set – directly set

– Mean airway pressureMean airway pressure Mean airway pressure (MAP)Mean airway pressure (MAP)

– An average pressure across airway An average pressure across airway – Good estimate of alveolar pressureGood estimate of alveolar pressure– Determined by PEEP and PIPDetermined by PEEP and PIP– Also influenced by inspiratory time Also influenced by inspiratory time

(It)(It)

Oxygenation – Getting OOxygenation – Getting O22 In In

Mean Airway Pressure (MAP)Mean Airway Pressure (MAP)– In CMV majority of MAP is In CMV majority of MAP is

determined by PEEPdetermined by PEEP– As rate increases, larger As rate increases, larger

contribution from PIPcontribution from PIP– Too little, not enough open alveoli Too little, not enough open alveoli

(and thus lung); too much, inhibit (and thus lung); too much, inhibit pulmonary blood flowpulmonary blood flow

Inspiratory Time (IInspiratory Time (Itt))

Monitoring – How Are We Monitoring – How Are We Doing?Doing?

Physical examPhysical exam– Chest riseChest rise– ColorColor– Examination of the chest: Examination of the chest:

Breath soundsBreath soundsAir exchangeAir exchangeExtra sounds, i.e., crackles, Extra sounds, i.e., crackles, wheezes, rhonchi…wheezes, rhonchi…

Radiographic studiesRadiographic studies

Monitoring – How Are We Monitoring – How Are We Doing?Doing?

GassesGasses

– pH, POpH, PO22, PCO, PCO22, serum bicarbonate , serum bicarbonate (calculated)(calculated)

– TcCOTcCO22 monitoring monitoring

– In vivo monitoringIn vivo monitoring

Now Let’s Talk Now Let’s Talk About VentilationAbout Ventilation

Some TermsSome Terms

Peak End Expiratory Pressure (PEEP)Peak End Expiratory Pressure (PEEP)– Maintains open alveoliMaintains open alveoli– Distending pressure across airwaysDistending pressure across airways

Peak Inspiratory Pressure (PIP)Peak Inspiratory Pressure (PIP)– Highest pressure reached during Highest pressure reached during

breathbreath– Provides pressure to move gas into Provides pressure to move gas into

lungs in positive pressure ventilationlungs in positive pressure ventilation ∆∆P = PIP - PEEPP = PIP - PEEP

– In general, determines tidal volumeIn general, determines tidal volume

PEEPPEEP

PEEPPEEP

PEEP 0 5 12 20 PEEP 0 5 12 20

Modes of VentilationModes of Ventilation

Assist Control (A/C, CMV)Assist Control (A/C, CMV)

Synchronized Intermittent Mandatory Synchronized Intermittent Mandatory Ventilation (SIMV)Ventilation (SIMV)


Assist Control (A/C, CMV)Assist Control (A/C, CMV)– The ventilator has a number of preset The ventilator has a number of preset

machine breaths, at a set tidal volume machine breaths, at a set tidal volume or inspiratory pressure level (Vt or Ior inspiratory pressure level (Vt or IPP) ) each minute.each minute.

– The patient is capable of initiating their The patient is capable of initiating their own spontaneous breaths in between own spontaneous breaths in between machine breathsmachine breaths Spontaneous breaths will be equal to Spontaneous breaths will be equal to

preset ventilator breathspreset ventilator breaths

Synchronized Intermittent Mandatory Synchronized Intermittent Mandatory Ventilation (SIMV)Ventilation (SIMV)– The ventilator has a number of preset machine The ventilator has a number of preset machine

breaths, at a set tidal volume or inspiratory breaths, at a set tidal volume or inspiratory pressure level (Vt or Ipressure level (Vt or IPP) each minute.) each minute.

– The patient is capable of initiating their own The patient is capable of initiating their own spontaneous breaths in between machine spontaneous breaths in between machine breathsbreaths Spontaneous breath will be whatever size the Spontaneous breath will be whatever size the

patient wants to takepatient wants to take Used most often in conjunction with Pressure Used most often in conjunction with Pressure

Support (PS)Support (PS)


Breath Delivery TypesBreath Delivery Types

Volume ControlVolume Control Pressure ControlPressure Control Pressure Regulated Volume ControlPressure Regulated Volume Control Spontaneous Breath TypesSpontaneous Breath Types

– CPAP (Continuous Positive Airway CPAP (Continuous Positive Airway Pressure)Pressure)

– Pressure SupportPressure Support– Volume SupportVolume Support– BiPAP (Biphasic Positive Airway Pressure)BiPAP (Biphasic Positive Airway Pressure)

Breath Delivery typesBreath Delivery types

Volume ControlVolume Control– Preset Vt, Respiratory Rate and sometimes Preset Vt, Respiratory Rate and sometimes

flowflow– Peak Pressure (PIP) is variable while the Peak Pressure (PIP) is variable while the

volume remains constant.volume remains constant.

Breath Delivery Types Breath Delivery Types (cont)(cont)

Pressure Control Ventilation (PCV)Pressure Control Ventilation (PCV)– Preset RR, Inspiratory Time and Inspiratory PressurePreset RR, Inspiratory Time and Inspiratory Pressure– Vt is variable while pressure remains constantVt is variable while pressure remains constant

Breath Delivery Types Breath Delivery Types (cont)(cont)

Pressure Regulated Volume Control (PRVC)Pressure Regulated Volume Control (PRVC)– Preset RR, Inspiratory Time and VtPreset RR, Inspiratory Time and Vt– Pressure is variable yet limited while Vt remains Pressure is variable yet limited while Vt remains

constantconstant

Continuous Positive Airway Pressure Continuous Positive Airway Pressure (CPAP)(CPAP)– Preset level of pressure added to the Preset level of pressure added to the

circuit as the patient exhales.circuit as the patient exhales.– The patient does all the workThe patient does all the work– No set RR or tidal volumeNo set RR or tidal volume– Used most often with Pressure SupportUsed most often with Pressure Support

Spontaneous Breath Delivery Spontaneous Breath Delivery TypesTypes


Pressure Support (PS)Pressure Support (PS)– Preset level of pressure added to the Preset level of pressure added to the

spontaneous breath during inspiration onlyspontaneous breath during inspiration only– This helps augment the patients tidal volumeThis helps augment the patients tidal volume– Pressure is constant but tidal volume variesPressure is constant but tidal volume varies


Volume Support (VS)Volume Support (VS)– Variable pressure support added to the Variable pressure support added to the

ventilator during inspiration only, to ventilator during inspiration only, to deliver a preset Vtdeliver a preset Vt Tidal volume is constant but pressure Tidal volume is constant but pressure

variesvaries


Biphasic Positive Airway Pressure (BiPAP)Biphasic Positive Airway Pressure (BiPAP)– Preset level of pressure added to the circuit Preset level of pressure added to the circuit

during both inspiratory and expiratory during both inspiratory and expiratory phases.phases.

– Differing levels of inspiratory and expiratory Differing levels of inspiratory and expiratory supportsupport

– The patient does all the workThe patient does all the work– No set RR or tidal volumeNo set RR or tidal volume

The Alphabet GameThe Alphabet Game

Combined Modes of VentilationCombined Modes of Ventilation– PRVC (pressure regulated volume control)PRVC (pressure regulated volume control)– APRV (airway pressure release ventilation)APRV (airway pressure release ventilation)– BiVentBiVent– BiLevelBiLevel– VAPS (volume assured pressure support)VAPS (volume assured pressure support)– VS (volume support)VS (volume support)– AutomodeAutomode

Determination of Ventilator Determination of Ventilator SettingsSettings

ModeMode– Depends on patientDepends on patient

Breath Delivery TypeBreath Delivery Type– Depends on patientDepends on patient

VtVt– 6-10cc’s/kg6-10cc’s/kg

RRRR– 12 – 40 bpm’s (depending on age & desired Minute Ventilation)12 – 40 bpm’s (depending on age & desired Minute Ventilation)

FiO2FiO2– Usually start at 100% Usually start at 100% – Less if patient has been on a vent for a whileLess if patient has been on a vent for a while

PEEPPEEP– Depends on patientDepends on patient

PSPS– Depends on patientDepends on patient

Patient ConsiderationPatient Consideration

HumidificationHumidification– HMEHME– Heated (37Heated (37◦◦ C & 44mg/L Water Vapor) C & 44mg/L Water Vapor)

SuctioningSuctioning– SalineSaline

NutritionNutrition– Enteral (Gavage)Enteral (Gavage)– Parenteral (TPN)Parenteral (TPN)

Sedatives, Analgesics, and Sedatives, Analgesics, and ParalyticsParalytics

SedativesSedatives

BenzodiazepinesBenzodiazepines OpioidsOpioids NeurolepticsNeuroleptics

BenzodiazepinesBenzodiazepines Drugs of choice for treatment of anxietyDrugs of choice for treatment of anxiety

– Relatively low costRelatively low cost– Muscle-relaxingMuscle-relaxing– AnticonvulsantAnticonvulsant– Amnesiac effectsAmnesiac effects

May cause respiratory depression if May cause respiratory depression if administered to COPD patients on opioidsadministered to COPD patients on opioids

Minimal cardiovascular effects, BP Minimal cardiovascular effects, BP depression possible in hemodynamically depression possible in hemodynamically unstable patientsunstable patients

Most common benzos in Most common benzos in ICUICU

Generic Name (Trade Name) ½ lifeGeneric Name (Trade Name) ½ life Diazepam (Valium)Diazepam (Valium) 20- 120 hrs 20- 120 hrs

– Rapid onset Rapid onset Midazolam (Versed)Midazolam (Versed) 3 – 11 hrs 3 – 11 hrs

– Onset 2-3 minutesOnset 2-3 minutes Lorazepam (Ativan)Lorazepam (Ativan) 8 – 15 hrs 8 – 15 hrs

– Onset 5 – 20 minutesOnset 5 – 20 minutes

OpioidsOpioids

Primarily used for pain reliefPrimarily used for pain relief Secondarily used for as anxiolytic and Secondarily used for as anxiolytic and

sedationsedation Many serious side effectsMany serious side effects

– Respiratory DepressionRespiratory Depression– NauseaNausea– ConstipationConstipation– VomitingVomiting– Cardiovascular depressionCardiovascular depression– Reduced GI motilityReduced GI motility– ConvulsionsConvulsions– High physical dependenceHigh physical dependence

OpioidsOpioids

Recovery period lengthened in Recovery period lengthened in renal/hepatic insufficiencyrenal/hepatic insufficiency

May cause histamine release and May cause histamine release and bronchoconstrictionbronchoconstriction

Reversal medicationReversal medication– Naloxone Hydrochloride (Narcan)Naloxone Hydrochloride (Narcan)

30 minutes half life30 minutes half life May require IV infusion for opioid withdrawalMay require IV infusion for opioid withdrawal

Most common Opioids in Most common Opioids in ICUICU

Generic name (Trade name)Generic name (Trade name) Fentanyl Hydrochloride (Sublimaze)Fentanyl Hydrochloride (Sublimaze)

– SyntheticSynthetic– 1 - 4 hours duration with fast onset1 - 4 hours duration with fast onset– 100 – 150 times more potent than MS100 – 150 times more potent than MS– Less cardiac side effects than MSLess cardiac side effects than MS

Morphine Sulfate (Duramorph)Morphine Sulfate (Duramorph)– 1- 6 hours duration with slower onset1- 6 hours duration with slower onset– Preferred for lower costPreferred for lower cost

NeurolepticsNeuroleptics Used to treat extreme agitation and Used to treat extreme agitation and

delirium (increased in elderly and delirium (increased in elderly and burn patients)burn patients)

Side effectsSide effects– Decreased seizure thresholdDecreased seizure threshold– Cardiac dysrhythmiasCardiac dysrhythmias– Parkinson’s-type symptomsParkinson’s-type symptoms

Muscle rigidityMuscle rigidity LethargyLethargy DrowsinessDrowsiness

Most common Neuroleptic Most common Neuroleptic Drug in ICU:Drug in ICU:

Generic name (Trade name)Generic name (Trade name) Haloperidol (Haldol)Haloperidol (Haldol)

– 3 - 5 minute onset3 - 5 minute onset– 5 - 24 hours half-life5 - 24 hours half-life

AnestheticsAnesthetics Used for sedative, hypnotic & amnesiac Used for sedative, hypnotic & amnesiac

propertiesproperties NO analgesic effectsNO analgesic effects Many hemodynamic effectsMany hemodynamic effects

– Decreased SVRDecreased SVR– Decreased BPDecreased BP– BradycardiaBradycardia

Good for IC bleedsGood for IC bleeds– Neurosurgical patients = decreases ICPNeurosurgical patients = decreases ICP

Rapid “wake-up”… no hangoverRapid “wake-up”… no hangover Painful on injectionPainful on injection Used in OR, ICU Used in OR, ICU Lipid based solution prone to contamination Lipid based solution prone to contamination

AnestheticsAnesthetics

Generic name (Trade name)Generic name (Trade name) Diprivan (Propofol)Diprivan (Propofol)

– Onset 1 minute, Onset 1 minute, – Half-life <30 minuteHalf-life <30 minute– ExpensiveExpensive

ParalyticsParalytics Used to:Used to:

– Facilitate mechanical ventilationFacilitate mechanical ventilation– Treat extreme agitationTreat extreme agitation– Facilitate intubation and other proceduresFacilitate intubation and other procedures– Manage tetanusManage tetanus– Extreme hyperventilationExtreme hyperventilation– Reduction of OReduction of O22 consumption & CO consumption & CO22 production production

Can causeCan cause– Decreased BPDecreased BP– Cardiac dysrhythmiasCardiac dysrhythmias– Prolonged paralysis in patients with Prolonged paralysis in patients with

renal/hepatic insufficiencyrenal/hepatic insufficiency

ParalyticsParalytics

NO SEDATIVE EFFECTSNO SEDATIVE EFFECTS NO ANALGESIC EFFECTSNO ANALGESIC EFFECTS Essentially it paralyzes your patient - Essentially it paralyzes your patient -

MUST be given WITH analgesic and MUST be given WITH analgesic and sedative!!sedative!!

ParalyticsParalytics

Generic name (Trade name)Generic name (Trade name) Panacuronium (Pavulon) Panacuronium (Pavulon) ““Vec” Vecuronium (Norcuron)Vec” Vecuronium (Norcuron) ““Rock” Rocuronium (Zemuron) Rock” Rocuronium (Zemuron) ““Sux”Sux” Succinylcholine (Anectine)Succinylcholine (Anectine)

Respiratory DiseasesRespiratory Diseases

PneumoniaPneumonia PEPE ARDSARDS Chest TraumaChest Trauma

PneumoniaPneumonia Definition:Definition:

– Inflammation process that primarily Inflammation process that primarily effects the gas exchange area’s of the effects the gas exchange area’s of the lunglung

Etiology:Etiology:– Bacteria, viruses, fungi, TB, etc.Bacteria, viruses, fungi, TB, etc.

Clinical Manifestation:Clinical Manifestation:– Initially dry cough, turning productive with Initially dry cough, turning productive with

blood streaked sputum, crackles, rhonchi, blood streaked sputum, crackles, rhonchi, dyspnea, cyanosisdyspnea, cyanosis

Treatment:Treatment:– OO22 therapy, bronchial hygiene, therapy, bronchial hygiene,

bronchodilators, antibioticsbronchodilators, antibiotics

Pulmonary EmbolismPulmonary Embolism Definition:Definition:

– Complete or partial obstruction of the Complete or partial obstruction of the pulmonary artery blood flow to a distal portion pulmonary artery blood flow to a distal portion of the lung by a plug brought by the bloodof the lung by a plug brought by the blood

Etiology:Etiology:– Blood clots (blood stasis, vessel wall Blood clots (blood stasis, vessel wall

abnormalities, abnormal blood abnormalities, abnormal blood coagulation), Fat, Tumors, Aircoagulation), Fat, Tumors, Air

Clinical Manifestation:Clinical Manifestation:– Asymptomatic to death, dyspnea and Asymptomatic to death, dyspnea and

sharp chest pain most common,sharp chest pain most common, Treatment:Treatment:

– OO22 therapy, anticoagulation therapy, therapy, anticoagulation therapy, steroids, embolectomysteroids, embolectomy

ARDSARDS Definition:Definition:

– An acute restrictive disease of An acute restrictive disease of ↓ing↓ing FRC and FRC and severe hypoxia due to injury to the alveolar severe hypoxia due to injury to the alveolar capillary membrane resulting in capillary membrane resulting in ↓ed surfactant, ↓ed surfactant, atelectasis and ↓ingatelectasis and ↓ing compliance compliance

Etiology:Etiology:– Shock (severe hemorrhage, trauma, MI, CVA, Shock (severe hemorrhage, trauma, MI, CVA,

CABG)CABG)– Inhalation (OInhalation (O22, aspiration, near drowning, burns), aspiration, near drowning, burns)– Infection (viral pneumonia, sepsis)Infection (viral pneumonia, sepsis)– Over-hydration, chemical injury, blood infusion, Over-hydration, chemical injury, blood infusion,

etc.etc. Clinical Manifestation:Clinical Manifestation:

– Rapid onset, dyspnea, hypoxia, tachypnea, Rapid onset, dyspnea, hypoxia, tachypnea, tachycardia, tachycardia, ↓ed compliance, ↓ed compliance,

Treatment:Treatment:– Treat underline cause, OTreat underline cause, O22, PEEP, CPT, Sx, , PEEP, CPT, Sx,

diuretics, ventilatordiuretics, ventilator

Chest TraumaChest Trauma Account for ¼ of all trauma deathsAccount for ¼ of all trauma deaths Blunt TraumaBlunt Trauma

– Steering wheelsSteering wheels– FallsFalls

Penetrating TraumaPenetrating Trauma– Knife woundsKnife wounds– GunshotsGunshots

Primary concernPrimary concern– ABCABC– C-SpineC-Spine

Chest TraumaChest Trauma Fractures/Flail chestFractures/Flail chest

– High or low fx, watch for concurrent injuriesHigh or low fx, watch for concurrent injuries PneumothoraxPneumothorax

– Spontaneous or trauma, < or >20%, 2Spontaneous or trauma, < or >20%, 2ndndICS ICS MCL or 5MCL or 5ththICS MALICS MAL

HemothoraxHemothorax– Mild <300cc, Moderate b/w 300-1400cc, Mild <300cc, Moderate b/w 300-1400cc,

Severe >1400ccSevere >1400cc– Drain, surgery for >200cc/hr, transfusionsDrain, surgery for >200cc/hr, transfusions

Sucking chest woundSucking chest wound– Open flap in chest wall, sucking sound, Open flap in chest wall, sucking sound,

tension pneumo ?, sterile dressing over 3 tension pneumo ?, sterile dressing over 3 sidessides

Questions?Questions?

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