Mechanical Ventilation ศ.พ.ญ.ส ณ ร ตน คงเสร พงศ ภาคว ชาว ส ญญ ว ทยา คณะแพทยศาสตร ศ ร ราชพยาบาล

Mechanical Ventilation ศ.พ.ญ.ส ณ ร ตน คงเสร พงศ ภาคว ชาว ส ญญ ว ทยา คณะแพทยศาสตร ศ ร ราชพยาบาล

Goal of Mechanical Ventilation Mechanical ventilation is any means in which physical device or machines are used to assist or replace mechanical ventilation Maintaining alveolar ventilation necessary to meet metabolic needs for oxygen uptake and carbon dioxide removal

Indication for mechanical ventilation Need for high level of inspired oxygen (hypoxic respiratory failure) Need for assist or control ventilation (hypercapnic respiratory failure, surgery) Organ protection Intracranial hypertension Pulmonary hypertensive crisis, severe abdominal hypertension Decrease work of breathing : heart failure, severe metabolic acidosis

Ventilator Support Strategies Total support Full support Partial support Weaning

Type of Mechanical Ventilation Negative pressure ventilation Positive pressure ventilation

Negative Pressure Ventilation Decrease effect of positive pressure ventilation Eg. Pulmonary hypertension? Adequacy of ventilation Pressure effect

Iron Lung Chest Cuirass

Positive Pressure Ventilation Non invasive positive Invasive positive pressure ventilation

Non invasive Positive Pressure Ventilation

Initiation or Trigger Mechanism Time trigger Pressure trigger Flow trigger

Limiting Mechanism Volume limited Pressure limited Flow limited

Cycling Mechanism Volume cycled Pressure cycled Time cycled Flow cycled

Mechanical Function in Positive Pressure Ventilation Mode Initiation Limit Cycle Volume Preset CMV Time Volume Volume/Time Assist/control Pressure Volume Volume/Time IMV Time Volume Volume/Time SIMV Time/pressure Volume Volume/Time Pressure Preset PSV Pressure Pressure Flow PCV Time Pressure Time

Mode of Mechanical Ventilation Controlled Ventilation Assist -Control Ventilation Synchronized intermittent mandatory ventilation Pressure support ventilation

Control Ventilation Assist/Control Ventilation Intermittent Mandatory Ventilation Pressure Support Ventilation Continueous Positive Airway Pressure Ventilation

Flow Trigger

Volume Control Ventilation

Pressure Control Ventilation

Pressure Regulated Volume Control Adaptive Pressure Ventialtion ( APV) Inverse Ratio Ventialtion

BIPAP Biphasic Positive Airway Pressure

High Frequency..High Oscillator Ventialtion

Continuous Care During Mechanical Ventilation Ventilator parameter Humidification and temperature Sedation and analgesia Weaning

Ventilator Parameter Inspiratory pressure I:E ratio FiO2 Minute ventilation

Recommendation for monitoring during mechanical ventilatory support CXR after intubation or deterioration ABG after initial setting Vital sign Measure inspiratory plateau Pulse oxymeter Ventilator alarm

Obstructive airway disease Asthma, COPD Support oxygenation and ventilation until primary pathology has resolved May produced hyperinflation, auto-peep, secondary hypotension

Obstructive airway disease More attention to the balance of the cycle of inspire and expire time (I:E) Adequate expire time Adequate peak inspiratory pressure

Restrictive airway disease Scoliosis morbid obesity Low tital volume, high rate Maintain minute ventilation

Ventilator Management in heart disease Decrease the work of breathing Ensure adequate oxygen delivery to the heart Heart lung interaction

Ventilator Management in heart disease Cardiogenic pulmonary edema may benefit from mechanical ventilation induced increase in intrathoracic pressure which will decrease LV filling Lower pulmonary capillary pressure) and decrease LV after load (increase stroke volume)

Problems & Complications Associated with Mechanical Ventilation Complications associated with mechanic Volume trauma Barotruma Asynchony Oxygen toxicity Nonsynchrony Complication associated in the process of treatment - Ventilator associated pneumonia - Heart lung interaction

Hypotension associated with mechanical ventilation Tension pneumothorax Converse from negative to positive intrathoracic pressure Auto -PEEP Acute MI

Weaning FiO2 Rate, IMV Pressure support T piece