Mechanical

PATRICK GERARD L. MORAL, M.D.PATRICK GERARD L. MORAL, M.D.

IINTUBATIONNTUBATION• Prevention of upper airway Prevention of upper airway

obstructionobstruction• Protection against aspirationProtection against aspiration• Facilitating tracheobronchial toiletFacilitating tracheobronchial toilet• Providing a closed system for Providing a closed system for

mechanical ventilationmechanical ventilation

VENTILATORY VENTILATORY

FAILUREFAILURE

REDUCED REDUCED CENTRAL DRIVECENTRAL DRIVE

IMPAIRED INSPIRATORY IMPAIRED INSPIRATORY MUSCLE PERFORMANCEMUSCLE PERFORMANCE

EXCESSIVE EXCESSIVE RESPIRATORY RESPIRATORY WORKLOADWORKLOAD

OOBJECTIVESBJECTIVES

• To support pulmonary gas To support pulmonary gas exchangeexchange– alveolar ventilationalveolar ventilation– arterial oxygenationarterial oxygenation

• To increase lung volumeTo increase lung volume• To reduce or manipulate work of To reduce or manipulate work of

breathingbreathing

PHYSIOLOGICAL

OOBJECTIVESBJECTIVES• To reverse hypoxemiaTo reverse hypoxemia• To reverse acute respiratory acidosisTo reverse acute respiratory acidosis• To relieve respiratory distressTo relieve respiratory distress• To prevent / reverse atelectasisTo prevent / reverse atelectasis• To reverse ventilatory muscle fatigueTo reverse ventilatory muscle fatigue• To permit sedation / neuromuscular blockadeTo permit sedation / neuromuscular blockade• To decrease myocardial oxygen consumptionTo decrease myocardial oxygen consumption• To reduce intracranial pressureTo reduce intracranial pressure• To stabilize chest wallTo stabilize chest wall

CLINICAL

• 700 - 900 mL700 - 900 mL• 15 LPM (self-inflating)15 LPM (self-inflating)• augment VTaugment VT

AAMBUBAG VENTILATIONMBUBAG VENTILATION

MMODESODES• Assist - ControlAssist - Control• SIMVSIMV• PSVPSV• CPAPCPAP• Servo-controlled Servo-controlled

BBASICASIC

VVAA = V = VTT - V - VDD

VVAA = V = VEE - V - VDD VA

VT

• Hook to mechanical ventilator with Hook to mechanical ventilator with

the following set-up:the following set-up:– mode: assist - controlmode: assist - control– VT: 500 mLVT: 500 mL– BUR: 15/ minuteBUR: 15/ minute– FiO2: 100 %FiO2: 100 %

• ABG 30 minutes after hooking to MVABG 30 minutes after hooking to MV• In-line nebulization q 6In-line nebulization q 6

OORDERSRDERS

FiO2FiO2

• 100 %100 %• dependent on target PaO2, dependent on target PaO2,

hemodynamic status, MAP, PEEP hemodynamic status, MAP, PEEP levellevel

OOXYGEN CONTENT XYGEN CONTENT

CaO2 =CaO2 = 1.34 mL x Hgb x SaO2 + .OO3 mL O2 x 1.34 mL x Hgb x SaO2 + .OO3 mL O2 x

PaO2PaO2

TTIDAL VOLUMEIDAL VOLUME

• Physiologic: 5 - 7 mL / KgPhysiologic: 5 - 7 mL / Kg• MV: 10 - 15 mL / KgMV: 10 - 15 mL / Kg• alveolar distending pressure: 35 alveolar distending pressure: 35

cm Hcm H22OO

BBASICASIC

VVAA = V = VTT - V - VDD

VVAA = V = VEE - V - VDD VA VD

mechanical

anatomic

alveolar

CCARDIAC OUTPUTARDIAC OUTPUT

hyperinflation

Increased pulmonary vascular resistance

Increased RV afterload

Decreased RV output

Decreased LV preload

Decreased LV output

• 4 to 20 / minute4 to 20 / minute• 8 to 12 / minute8 to 12 / minute• dependent on:dependent on:

– delivered VTdelivered VT– metabolic ratemetabolic rate– target PaCO2target PaCO2– level of spontaneous ventilationlevel of spontaneous ventilation

RRESPIRATORY RATEESPIRATORY RATE

• 40 to 100 L/ minute40 to 100 L/ minute• determined by level of determined by level of

spontaneous breathing effortspontaneous breathing effort

FFLOW RATELOW RATE

• Inspiratory time: 0.8 to 1.2 sInspiratory time: 0.8 to 1.2 s• I:E 1:2 to 1:1.5I:E 1:2 to 1:1.5

IINSPIRATORY TIME / I:E RATIONSPIRATORY TIME / I:E RATIO

• Respiratory rate: 20 / minuteRespiratory rate: 20 / minute60 seconds / 20 = 3 seconds = T60 seconds / 20 = 3 seconds = Ttottot

at an I:E ratio of 1:2:at an I:E ratio of 1:2:TTII = 1 second = 1 secondTTEE = 2 seconds = 2 seconds


• Respiratory rate: 30 / minuteRespiratory rate: 30 / minute60 seconds / 30 = 2 seconds = T60 seconds / 30 = 2 seconds = Ttottot

at an I:E ratio of 1:1:at an I:E ratio of 1:1:TTII = 1 second = 1 secondTTEE = 1 second = 1 second


• -0.5 to 1.5 cm H20-0.5 to 1.5 cm H20• most sensitive level that prevents most sensitive level that prevents

self-cyclingself-cycling

SSENSITIVITYENSITIVITY

• High pressureHigh pressure• Low pressureLow pressure

PPRESSURE ALARMSRESSURE ALARMS

• Low pressureLow pressure– check connections between tubings check connections between tubings

and patientand patient– deflated cuff deflated cuff – extubationextubation


• High pressureHigh pressure– bronchoconstrictionbronchoconstriction– airway obstructionairway obstruction– barotraumabarotrauma– right main bronchus obstructionright main bronchus obstruction– kinked endotracheal tubekinked endotracheal tube


• Cascade humidifierCascade humidifier• heats carrier gas to 37 C heats carrier gas to 37 C • holds 44 mg H20 / L gasholds 44 mg H20 / L gas• water replacementwater replacement• increases volume and decreases increases volume and decreases

viscosity of the sputumviscosity of the sputum

HHUMIDIFICATIONUMIDIFICATION

• Chest radiographChest radiograph• Arterial blood gasArterial blood gas• OximetryOximetry• CapnographyCapnography

AANCILLARYNCILLARY

• BarotraumaBarotrauma• Oxygen toxicityOxygen toxicity• Patient-ventilator asynchronyPatient-ventilator asynchrony• CardiovascularCardiovascular• RenalRenal• GastrointestinalGastrointestinal

CCOMPLICATIONS OMPLICATIONS

Mechanical

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