how much is normal physiological dead space

Usually an ETCO2 above 45mmHg requires manual or mechanical ventilation assistance. ETCO2 can 'potentially' monitor PaCO2 without having to perform arterial blood gas sampling, but ideally an arterial blood gas sample should be obtained so that all respiratory information is available to the anesthetist. It is a good indicator of how well a patient is ventilating. A relationship exists between ETCO2 and PaCO2 - ETCO2 is usually 2- 5 points LOWER than PaCO2. Changes in ETCO2 will occur before decreases in SPO2. ETCO2 allows a noninvasive method of measuring patient ventilation during anesthesia.

These adaptors should be utilized when the diameter of the ET tube is the same or smaller than the pediatric ETCO2 adaptor.ĮTCO2 is the amount of CO2 expelled at the end of a breath. Pediatric ETCO2 adaptors should be utilized when available on small patients. Too many adaptors are present – use only one. Cracks are present in the breathing systemģ.

If inspiratory CO2 (inCO2) is not 0 than the O2 flow rate is increased until inCO2=0.Ģ. Flow rates are not adequate – sometimes an O2 flow rate of 1-2 L/min is not adequate in a non rebreathing system. Negative dead space is a very REAL possibility in small patients if:ġ. the volume of dead space is greater than tidal volume (10-15mls/kg). Negative dead space occurs when NO ventilation is taking place i.e. Negative dead space is a concern in patients under 6kgs (≈ 12lbs). parts of the bronchial and respiratory system that do not participate in O2 and CO2 exchange. Exhausted soda lime or non functioning one way valves can also cause increases in dead space.īoth 1 & 2 (anatomic and alveolar) make up physiological dead space i.e. Mechanical: includes endotracheal tube adaptors, 'Y' and elbow adaptors on anesthetic circuits, respiratory & ETCO2 adaptors. Alveolar: alveoli that do not participate in CO2 or O2 exchangeģ. Anatomic: the upper portion of the airway that does not participate in ventilation e.g. Oxygen and CO2 are moved by pressure gradients.ĭead Space is an area where mixing of inspired and expired gases occur in the absence of gas exchange. Air that is being replaced in the lung has a higher partial pressure of O2 but a lower partial pressure of CO2. Ventilation is the act or process of supplying fresh air and moving gas in and out of the alveoli.

How much is normal physiological dead space