MODES OF VENTILATION

MECHANICAL VENTILATIOR: MODESNISHA KAUSHIKMSC NURSING 1ST YEARMEDICAL SURGICAL NURSING

INTRODUCTION Over 60% of patients appropriately admitted to ICU require endotracheal intubation and mechanical ventilation.

Mechanical ventilator is a machine designed to mechanically move breatheable air into and out of the lungs, to provide the mechanism of breathing for a patient who is physically unable to breathe, or breathing insufficiently.

Mechanical ventiation is ventilation of the lungs by artificial means usually by a ventialtor.INDICATION OF MECHANICAL VENTILATORRespiratory failure Pneumonia, ARDS, COPD, acute severe asthma, aspirationCirculatory failureCardiac arrest, pulmonary edemaNeurological diseaseComa, status epilepticus, drug overdose, head injuryMultiple traumaCLASSIFICATION OF MECHANICAL VENTILATORSMECHANICAL VENTILATIONINVASIVE NON INVASIVEFULLSUPPORTPARTIALSUPPORTPOSITIVEPRESSURENEGATIVEPRESSURECMVSIMVPSVBiPAP

VOLUMECONTROLPRESSURECONTROLCPAPBiPAPNIPPVCUIRASSTANK" iron lung rocking bed5ABBREVATIONS USEDCMV -Continuous mandatory ventilationSIMV Synchronized intermittent mandatory ventilationPSV Pressure support ventilationBIPAP-Bi level positive airway pressureCPAP- Continuous positive airway pressureNIPPV- Non invasive intermittent positive pressure ventilation

MODES OF VENTILATORSThe variable method by which the patient and the ventilator interact to deliver effective ventilation are called MODES.

The ventilator mode selected is based on how much work of breathing (WOB) the patient ought to or can perform

OR

Mode of ventilator is determined by the patients ventilatory status, respiratory drive and ABGs values.

MODES OF MECHANICAL VENTILATIONInvasive Mechanical VentilatorIntermittent positive pressure ventilationFull support CMV (controlled mechanical ventilation)Partial supportSIMV, PSV, BiPAPNon Invasive Mechanical VentilatorPositive pressure CPAP, BiPAP, NIPPV Negative pressureCuirass Tank iron lung Rocking bed

CONTROLLED MANDATORY VENTILATION(CMV)

Pre-set rate and tidal volume.

Independent of patients ventilatory efforts.

It is used when patient has no drive to breath. SYNCHRONIZED INTERMITTENT MANDATORY VENTILATION (SIMV)Pre-set of mandatory breaths with pre-set tidal volume.

Allows spontaneous breaths between mandatory breaths.

Allows patient to settle on ventilator with less sedation.PRESSURE SUPPORT VENTILATION (PSV)Breaths are triggered by patient.

Provide positive pressure to augment patients breaths.

Useful for weaning.

Usually combined with CPAP; may be combined with SIMV

POSITIVE END EXPIRATORY PRESSURE (PEEP)Positive airway pressure applied during expiratory phase in patients receiving mechanical ventilation.

Improves oxygenation by recruiting atelectatic or odematous lung.

CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP)Positive airway pressure applied throughout the respiratory cycle, via either an endotracheal tube or a tight fitting facemask.

Deliver only one level of air pressure.

Helps in breathing by applying continuous pressure to the airways.

CPAP machine demand extra effort from the patient to get in and out of the air.

BI- LEVEL POSITIVE AIRWAY PRESSURE(BiPAP)Deliver two different levels of air pressure.

BiPAP exerts high pressure when the patient breath in and deliver low pressure when they breathe out.

BiPAP machine comes with dual pressure adjustments, it helps patients to get more air in and out without much effort. NON INVASIVE INTERMITTENT POSITIVE PRESSURE VENTILATION (NIPPV)Most modes of ventilation may be applied via a facemask or nasal mask.

Usually PSV/BiPAP (typically 15-20 cmH2O) often with back-up mandatory rate.

Indications include acute exacerbations of COPD.CUIRASS TANK IRON LUNG ROCKING BED

CUIRASS TANK IRON LUNG ROCKING BED Early negative pressure ventilators were known as iron lungs.The patients body was encased in an iron cylinder and negative pressure is generated.The use of negative-pressure ventilators is restricted in clinical practice.INNOVATION IN MECHANICAL VENTILATION MODESHIGH FREQUENCY VENTILATIONHFV involves delivery of a small tidal volume(usually 1 to 5 ml per kg of body weight)at rapid respiratory rates(100 to 300 breaths per minute) in an effort to recruit and maintain lung volume and reduce intrapulmonary shunting.

It is used in patients with acute respiratory distress syndrome.PARTIAL LIQUID VENTILATIONCurrently, clinical trials are investigating the use of perflurocarbon(Liqui vent) in partial liquid ventilation for patients with ARDS.

Perflurocarbon is trickled down a specially designed ET tube through a side port into the lungs of mechanically ventilated patient.

The amount used is usually equivalent to a patients functional residual capacity. 20PARTIAL LIQUID VENTILATIONPerflurocarbon evaporates quickly and must be replaced to maintain a constant level during the therapy(usually 3 to 5 days).

Patients receiving PLV need close observation. Frequent assessment of vital signs ,ABGs , and continuous SpO2 monitoring are required before, during and after PLV.

SUMMARY Mechanical ventilation is ventilation of the lungs by artificial means usually by a ventilator.Indication are pneumonia,COPD,ARDS,coma,head injury etc.Ventilator are of two types :invasive and non invasive.The variable method by which the patient and the ventilator interact to deliver effective ventilation are called MODES.Modes are CMV,SIMV,BIPAP,CPAP,PEEP,PSV,PLV and HFV.

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