MECHANICAL

VENTILATION

BASICS……?????Respiration-Ventilation 3D Medica

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MEANING

A mechanical ventilator is a positive- or negative-pressure breathing device that can maintain ventilation and oxygen delivery for a prolonged period

INDICATIONSProtection of airwayRespiratory arrest or rate < 8/minTachypnoea > 35/minInability to tolerate oxygen

mask/CPAP/NIV, e.g. agitation,confusion

Removal of secretionsHypoxaemia (Pa O2 < 8 kPa (<

60 mmHg); Sp O2 < 90%),despite CPAP with F iO2 > 0.6

Hypercapnia if conscious level impaired or risk of raised intracranial pressure

Worsening respiratory acidosisVital capacity falling below 1.2 L

in patients with neuromuscular disease

Removing the work of breathing in exhausted patients

CLINICAL CONDITIONSPost-operative

• e.g. After major abdominal or cardiac surgery

Respiratory failure ARDS Acute severe asthma Pneumonia Aspiration COPD Smoke inhalation, burns

Circulatory failure Low cardiac output: cardiogenic

shock Following cardiac arrestPulmonary oedema

Neurological diseaseComa of any cause Status epilepticus Drug overdoseRespiratory muscle failure (e.g. Guillain–Barré

syndrome, poliomyelitis, myasthenia gravis) Head injury: to avoid hypoxaemia and

hypercapnia, and reduce intracranial pressure

Bulbar abnormalities causing risk of aspiration (e.g. cerebrovascular accident, myasthenia gravis)

 Multiple trauma

TERMINOLOGYTRIGGERTIDAL VOLUMERESPIRATORY RATEPOSITIVE END EXPIRATORY

PRESSUREFLOW RATEINSPIRATORY TIME EXPIRATION

INVASIVE

IPPV

FULL SUPPORT

CMV

VOLUME CONTROL

PRESSURE CONTROL

PARTIAL SUPPORT

SIMV PSV

NON INVASIVE

+ve pressure via nasal or face mask

NIPPV BiPAP

-ve pressur

e

CURASS TANK

IRON LUNG

Intermittent positive pressure ventilation (IPPV)

Controlled mandatory ventilation (CMV)

Synchronised intermittent mandatory ventilation (SIMV)

Pressure-controlled ventilation (PCV)

Pressure support ventilation (PSV)/Assisted spontaneousbreathing (ASB)

Positive end-expiratory pressure (PEEP)

Continuous positive airways pressure (CPAP)

Bi-level positive airway pressure (BiPAP/BIPAP)

Non-invasive positive pressure ventilation (NIPPV/NIV)

Inverse ratio ventilation

High-frequency ventilation (hfv)

Liquid ventilation

INITIAL VENTILATOR SETTINGS

Assess the modeTidal volume and ratePatient or time triggered MINUTE VENTILATION=RATE X TIDAL

VOLUMEIMV AND SIMV

TOTAL MINUTE VENTILATION= MINUTE VOLUME MACHINE+ MINUTE VOLUME SPONTANEOUS

TOTAL MINUTEVOLUME= (MACHINE TIDAL VOLUME X MACHINE RATE )+ AVERAGE SPONATANEOUS TIDAL VOLUME X SPONATNEOUS RATE)

INSPIRATORY FLOW RATE= SET MINUTE VENTILATION/PERCENTAGE INSPIRATORY TIME X 0.01

AIRWAY RESISTANCE = INCREASING PEAK PRESSURE- PLATEAU PRESSURE/ INSPIRATORY FLOW(L/S)

FIO2 REQUIRED =

PaO2 DESIRED PaO2 /PAO2 PaCO2 X 12.5)

1PB- PH2O

INITIAL PaO2/FiO2 = DESIRED PaO2/FiO2

Optimal peepDO2 = QT X CAO2Alveolar ventilationVA =( VT – V D) FPaCO2 = 0.863X VCO2/ VA

INITIAL PaCO2 X VA= DESIRED PaCO2 X VA

INITIAL PACO2 X F = DESIRED PaCO2 X F

INITIAL PACO2 X VT = DESIRED PaCO2 X VT

ASSESSING THE EQUIPMENT

VENTILATOR

PROBLEMS

PATIENT PROBLEMS

COMPLICATIONS

MANAGEMENT

WEANINGVital capacity:10 to 15 mL/kg Maximum inspiratory pressure

(MIP) at least –20 cm H2O Tidal volume: 7 to 9 mL/kgMinute ventilation: 6 L/minRapid/shallow breathing index:

below 100 breaths/minute/L; PaO2 _60 mm Hg with FiO2 less than 40%

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NURSE WHAT YOU DO..???

REFERENCES Mason R.J, Braaddus V.C.Murray and Nadel`s :Textbook of

Respiratory Medicine. 5th edn. Philadelphia:Saunders;2010.

George R.B,Light R.W. Chestmedicine:Essentials of Pulmonary and Critical Care Medicine. 4th edn . Philadelphia:Lippincott;2000.

Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL, Jameson JL, et al., editors. Harrison’s principles of internal medicine. 17th ed. New York: McGraw Hill; 2008

Johnson J.Y.Brunner anD Suddharth`s:Textbook of Medical Surgical Nursing. 11th edn. Philadelphia:Lippincott;2008.

Black M.J, Hawks H.K. Medical Surgical Nursing. 7th edn. Missouri: Saunders;2005