Question

what parameter do we evaluate to assess a patient ability to adequately ventilate? explain.

Answer 1

Ventilation is a life caring system, they support adequate lung function in patients they are critical condition or under general anaesthetic condition. The ventilator delivers gas to the lungs with either negative or positive pressure.

The basic parameters includes

Tidal volume

Respiratory rate

Minute ventilation

Lung pressures

-peak pressure

-platue pressure

Flow or inspiratory time

Flow pattern

Trigger

FiO2

PEEP

Tidal volume

It is the amount of air delivered with every breath. injured and uninjured lungs use of low tidal volume has been preferred over high tidal volume. The initial tidal volume is set between 6 and 8 ml/kg of predicted body weight. Tidal volume less than or equal to 6 ml/kg of predicted body weight have been recommended for acute respiratory distress syndrome patients.

Positive end expiratory pressure

PEEP is the the alveolar pressure should be higher than atmospheric pressure at the end of expiration. It applies through ventilation deliver the positive pressure at the end of expiration to prevent unstable lung units from collapsing. Low levels of PEEP are routinely used for the ventilation.

Respiratory rate

During mechanical ventilation, the respiratory rate should be adjustedbfor maintaining minute volume appropriate to the patient metabolic need. If higher respiratory rate , maintain carbon dioxide level in safe range. Inspiratory to expiratory ratio alters, leading to intrinsic PEEP due to short expiratory time.

Inspiratory airflow

It must be adjusted during ventilation. So it can cause lung damage. High inspiratory airflow cause high damage to the lung parenchyma. High inspiratory airflow is an indication for pulmonary stress.

Peak pressure

Maximum pressure measured at the end of inspiration. In normal persons airway resistance do not exceed 15-20 cm H2O/L/s under controlled mechanical ventilation. During ventilation pressure peak depends on tidal volume, respiratory rate, airflow.

Plateau pressure

It should measured during inspiratory pause. When the respiratory muscles relaxed and equal to alveolar pressure, the airflow is zero. Plateau pressure can be affected by changes in tidal volume and