how much is normal physiological dead space

Anatomic and instrument dead space are generally fixed.Alveolar dead space – dysfunctional alveoli which receive ventilation but don't exchange CO2 well (or at all).Instrument dead space – for intubated patients, this includes any tubing interposed between the patient's airway and the site of fresh gas insufflation.Anatomic dead space (e.g., trachea and large bronchi) – with each breath gas enters these areas, but doesn't participate in gas exchange.Dead space refers to inhaled gas that doesn't participate in carbon dioxide clearance.If the etCO2 curve doesn't reach a plateau, then the numeric value is less reliable. Both the numeric value and the shape of the etCO2 tracing are important.Waveform capnography should be monitored in all intubated patients and displayed on the monitor (as above).etCO2 is a measurement of the partial pressure of CO2 in gas expired at the end of exhalation (when exhaled gas will most closely resemble the alveolar CO2 concentration).

Understanding how to interpret etCO2 waveforms.

Understanding changes in etCO2 within the context of other data (especially trends in minute ventilation).

Paying attention to etCO2 values (e.g., noting them daily in reviews of the patient, along with other vital signs).

Within the next decade, continuous waveform capnography will likely become a universal standard of care across all well-resourced intensive care units.Īs the use of waveform capnography expands, we need to be thoughtful about integrating this into our practice. Capnography is increasingly recommended both to confirm endotracheal tube insertion and to subsequently monitor the patency and effectiveness of ventilation throughout the duration of intubation.

Capnography was pioneered in the operating room, but the safety implications for all critically ill patients are clear (the standard of safety monitoring in the ICU shouldn't be lower than in the operating room). Failure to use waveform capnography contributed to >70% of ICU-related airway deaths in the NAP4 audit. Waveform capnography is emerging as a standard monitoring tool to improve safety among intubated patients. Introduction – an emerging standard of care

How much is normal physiological dead space