towergift.blogg.se - Normal range of capnography

Professionals are able to identify potential breathing complications (such as airway obstruction, hyperventilation, hypoventilation, or apnoea) and respond accordingly with a change in clinical management.

The wider use of EtCO 2 monitoring in different clinical areas reflects its importance as a monitoring tool that gives indication into three crucial aspects: the patient’s airway patency, breathing adequacy and circulatory status. House of Delegates of ASA (2011) “During moderate or deep sedation, the adequacy of ventilation shall be evaluated by continual observation of qualitative clinical signs and monitoring for the presence of exhaled carbon dioxide unless precluded or invalidated by the nature of the patient, procedure, or equipment.” 7ĪAGBI (2015) “Continuous capnography should be used for all patients undergoing moderate or deep sedation, and should be available wherever any patients undergoing anaesthesia or moderate or deep sedation are recovered.” 8

Several guidelines have supported the use of capnography outside the theatre environment:ĪLS Guidelines (2015) mention “Waveform capnography must be used to confirm and continually monitor tracheal tube placement, and may be used to monitor the quality of CPR and to provide an early indication of return of spontaneous circulation (ROSC).” 6 The following image is taken from SedateUKĪlthough it has been historically used by anaesthetists during general anaesthesia, End Tidal CO 2 monitoring is becoming more common in other clinical areas like emergency environments, critical care, during sedation practice, in ambulatory settings and in post-operative recovery units. Phase IV: start of inhalation, CO 2 decreases to zero as atmospheric air enters the airway.This phase ends with a value of maximum CO 2 concentration Phase III: CO 2 concentration is relatively constant (reflects the concentration of CO 2 in the alveolar gas).Phase II: CO 2 increases rapidly as alveolar gas exits the airway.Phase I: start of exhalation, CO 2 concentration is initially zero.

There is a similar shape for subjects with normal lung function.

The width of the waveform depends on expiratory time.

The amplitude of the waveform depends on EtCO 2 concentration.

A maximum CO 2 is reached with each breath, corresponding to EtCO 2.

The waveform shape always starts at zero and returns to zero.

Whilst it is fairly easy to interpret numerical values for EtCO 2 and RR, interpretation of the waveform shape requires specific knowledge discussed below.Ī normal capnogram always has the following features: When monitoring End Tidal CO 2, there are 3 aspects to consider: the EtCO 2 value, the waveform shape and the respiratory rate (RR). The Microstream monitor has a rapid response time and may be used with both invasive and non-invasive ventilation. The newest type of EtCO 2 monitor is Microstream which uses molecular correlation spectrography for greater precision. But mainstream monitors increase mechanical dead space, depending on size of the chamber used to collect a gas sample, while adding weight on the airway, and can’t be used for non-invasive ventilation. This allows a more rapid response time and requires a smaller amount of sample gas than sidestream monitoring. Mainstream monitors have a sampling window which is inserted directly in-line with the ventilator circuit for CO 2 measurement. Sidestream monitors can be used with non-invasive ventilation. Gas samples are aspirated from exhaled gas flow via the ventilator circuit and are read at the monitor. Sidestream monitors rely on a separate monitor connected to the patient’s airway by a tube. There are 3 main types of End Tidal CO 2 monitors: sidestream, main¬stream, and Microstream.