Mechanical VentilationIntroduction & Application for Physical Therapists

Lindsey Montana Fan, PT, DPT, CCSNYPTA Greater District of New York

September 10th, 2014

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Objectives

Understand the premise & main indications for mechanical ventilation

Obtain/interpret information on settings & patient performance from ventilator screen

Become familiar with basic ventilator terminology & modes

Identify PT treatment indications for mechanically ventilated & weaning patients

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Why not wait until the patient is extubated?

Muscle Strength decreases 1.3-3% for each day the healthy individual spends on bedrest (Topp, et al. 2002)

Effects are even more profound in older individuals & those with critical illness (Yende, et al.

2006)

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Ventilation

Ventilation is the process by which gases are moved in & out of the lungs

Spontaneous Ventilation is a result of negative intrathoracic pressure being created by the inspiratory muscles Muscles contract & pull on pleura Pressure in the intrapleural space decreases Negative pressure gradient pulls air from the atmosphere into the

lungs

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Mechanical Ventilation

Mechanical Ventilation is the use of artificial means to support or replace spontaneous ventilation

Mechanical Ventilation must satisfy a patient’s respiratory needs without Damaging the lungs Impairing circulation Causing patient discomfort

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Indications Mechanical Ventilation

Hypoxemic Respiratory Failure Inadequate Gas Exchange Decrease in PaO2 Inability to maintain % oxygen

saturation

Hypoventilation V/Q mis-match Diffusion Impairment

Hypercapnic Respiratory Failure Increase in PaCO2 Inability to ventilate

Respiratory muscle fatigue Neuromuscular disorders CNS depression Musculoskeletal disorders

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Indications Mechanical Ventilation

Airway Protection Preventative Measure

Cardiac Arrest Life-saving measure

Management of ICP Creation of alkalosis --> vasoconstriction --> decreased cerebral blood flow/reduction of ICP

Airway Obstruction Maintenance of patent airway

Surgery or Trauma General Anesthesia

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Delivery

Endotracheal TubeNasal Endotracheal TubeTracheostomy

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Key Units of Measurement

Volume mL

Pressure cmH2O

Flow L/min

Rate Breaths/min

FiO2 %

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Types of Mechanical Ventilation

Pressure Ventilation Negative pressure ventilation

• Iron Lung• Chest Cuirass

Positive pressure ventilation• The application of positive pressure to the lungs to

improve gas exchange • The opposite of natural “spontaneous breathing”

Volume Ventilation The application of supplemental volume to the lungs to improve gas

exchange

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Screen Organization

Patient Performance Data

Clinician Entered Settings

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Modes: Assist-Control

Full Ventilatory SupportMandatory breaths delivered at set parameters

RateInspiratory Pressure or VolumeFiO2PEEP

Ventilator will also support any patient-triggered breaths at these set parameters

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Assist-Control Settings ViewMode

Pressure Control (PC)

Rate (f)

Inspiratory Pressure (PI)

FiO2 (O2 %)

PEEP

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Assist-Control Performance Data View

Type of Breath Delivered (A or C)

Respiratory Rate (fTOT)

Tidal Volume (VTE)

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Modes: Spontaneous

All breaths are initiated & terminated by the patient.

Ventilator assists the patient’s inspiratory efforts toOver-come airway resistance Augment tidal volumesDecrease work of breathing

Mode SettingsPressure SupportFiO2PEEP

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Spontaneous Settings View

Mode Spontaneous (SPONT)

Pressure Support (PS)

FiO2 (O2 %)

PEEP

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Spontaneous Performance Data View

Type of Breath Delivered (S)

Respiratory Rate (fTOT)

Tidal Volume (VTE)

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PEEP

Positive End Expiratory Pressure

Elevates baseline pressure at which inspiration is delivered

Increases alveolar recruitment & surface area available for gas exchange

Prevents alveolar collapse at end-expiration

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Alarms

Red AlarmsCircuit DisconnectApnea

Yellow AlarmsLow Tidal VolumeHigh Respiratory RateHigh Pressure

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Adverse Side-Effects Prolonged Exposure to Mechanical Ventilation

Impaired CirculationDecreased Cardiac Out-putVentilator-Induced Lung InjuryRespiratory Muscle AtrophyBarotraumaVentilator-Associated Pneumonia

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Application for Physical Therapists

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PT Considerations Call Respiratory Therapy

For status update, notification, & assistance Understand hospital policy

Schedule Assistant Time

Monitor Patient Performance Top of ventilator screen Vital signs

Suctioning Competency Ballard/Closed In-Line Suction

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ET Tube Placement

Placement indicator at level of teeth or lip

Confirm placement with RT or RN before & after mobilization

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Documentation

Assist-Control

ModeInspiratory Pressure or

VolumeSet RateFiO2PEEP

Spontaneous

ModePressure SupportFiO2PEEP

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Ventilator Weaning

Ventilatory discontinuance. The process of reducing ventilator support

Goal: Restoration of pt.’s ability to independently & adequately ventilate without the mechanical ventilator

Changing the modeChanging the settingsTrach collar trial/T-piece trial

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Weaning Considerations

VO2 increases with all forms of exercise Increase in cardiac out-put Increase O2 extraction across capillary beds

Spontaneous breathing trials Reduction of Ventilator support Pressure Support/Trach Collar

Can increase cardiovascular work-load

Tailor treatments accordingly Monitor patient tolerance Provide adequate rest periods

MORE vent support is BETTER For PT/OT during preliminary weaning trials Exercise clinical judgement

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Exercise Intolerance

In the setting of increasing workload...

Increasing respiratory rateDecreasing tidal volumesIncreasing accessory muscle use

Looks for the signs, know when to take a break!

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Safety & Feasibility---The Evidence Mobilization with Patients Receiving Mechanical Ventilation

One study conducted 1,449 activity events in 103 mechanically ventilated patients. Adverse activity-related events occurred in <1% No patients were extubated during activity (Bailey, et al. 2007)

Another study conducted PT & OT in 49 mechanically ventilated patients on a median of 1.5 days s/p intubation Therapy was provided on 90% of MICU days 89% of patients encountered had at least 1 potential barrier to

mobilization in addition to mechanical ventilation Therapy was interrupted prematurely in only 4% of all sessions (Pohlman, et al.

2010)

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Evidence Continued

Prospective, observational study 179 mobilization therapies with 63 critically ill patients

Patient level of mobilization achieved by Physical Therapists was significantly higher than that achieved by Registered Nurses (Garzon-Serrano, et. al 2011)

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Early Mobilization

A strategy for whole-body rehabilitation---consisting of interruption of sedation & physical & occupational therapy in the earliest days of critical illness

Safe & effectiveBetter functional outcomes at hospital dischargeShorter duration of deliriumMore ventilator-free days compared with standard of

careDecreased length of hospital stay (Schweickert, et al. 2009)

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References Bailey P, Thomsen G, Spuhler V, et al. Early activity is feasible and safe in respiratory failure patients. Crit Care Med. 2007(35): 139-145.

Frownfelter D, Dean E. Cardiovascular and Pulmonary Physical Therapy: Evidence and Practice. Missouri: Mosby Elsevier; 2006.

Garzon-Serrano J, Ryan C, Waak K, et al. Early mobilization in critically ill patients: patients’ mobilization level depends on healthcare provider’s profession. PM&R. 2011(3): 307-313.

Hillegass E, Fick A, Pawlik A, et al. Supplemental oxygen utilization during physical therapy interventions. Cardiopulmonary Physical Therapy Journal. 2014(25): 38-49.

Korupolu R, Gifford J, Needham D. Early mobilization of critically ill patients: reducing neuromuscular complications after intensive care. Contemporary Critical Care. 2009(6): 1-12.

Kress J. Clinical trials of early mobilization of critically ill patients. Crit Care Med. 2009(37):s442-s447.

Martin K. Mechanical ventilation: an overview. RC Educational Consulting Services, Inc. Apr 2000.

Patman S, Dennis D, Hill K. Exploring the capacity to ambulate after a period of prolonged mechanical ventilation. Journal of Critical Care Med. 2012(27): 542-548.

Pinsky M. Breathing as exercise: the cardiovascular response to weaning from mechanical ventilation. Intensive Care Med. 2000(26): 1164-1166.

Pohlman M, Schweickert W, Pohlman A, et al. Feasibility of physical and occupational therapy beginning from initiation of mechanical ventilation. Crit Care Med. 2010(38): 2089-2094.

Schweickert W, Pohlman M, Pohlman A, et al. Early physical and occupational therapy in mechanically ventilated, critically ill patients: a randomised controlled trial. Lancet. 2009(373): 1874-82.

Topp R, Ditmyer M, King K, et al. The effect of bedrest and potential of prehabilitation on patients in the intensive care unit. AACN Clin Issues. 2002(13): 263-276.

Wilkins R, Stoller J, Scanlan C. Egan’s Fundamentals of Respiratory Care. Missouri: Mosby; 2003.

Yende S, Waterer G, Tolley E, et al. Inflammatory markers are associated with ventilatory limitation and muscle dysfunction in obstructive lung disease in well functioning elderly subjects. Thorax. 2006(61): 10-16.

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