Respiratory Gas Analysis - Revision history

Bara at 16:10, 25 January 2011

2011-01-25T16:10:44Z

Suzannah.stacey: /* Capnograph */

2010-09-08T10:50:14Z

Capnograph

Suzannah.stacey at 10:48, 8 September 2010

2010-09-08T10:48:33Z

Karag7: /* End-Tidal Carbon Dioxide */

2009-09-03T13:00:35Z

End-Tidal Carbon Dioxide

A.allison at 15:14, 1 September 2009

2009-09-01T15:14:17Z

Hstenning at 19:44, 11 April 2009

2009-04-11T19:44:16Z

Hstenning at 19:09, 11 April 2009

2009-04-11T19:09:24Z

Hstenning: New page: {{unfinished}} ==Introduction== Most patients undergoing a general anaesthetic are maintained on inhalation agents and therefore in a situation where they will be connected to an anaesthe...

2009-04-09T14:00:22Z

New page: {{unfinished}} ==Introduction== Most patients undergoing a general anaesthetic are maintained on inhalation agents and therefore in a situation where they will be connected to an anaesthe...

New page

{{unfinished}}

==Introduction==
Most patients undergoing a general anaesthetic are maintained on inhalation agents and therefore in a situation where they will be connected to an anaesthetic machine. This means that with the inhalation agent, oxygen or medical air will also be delivered as well as nitrous oxide in some cases. It is important, as in any anaesthetic, to monitor the respiratory function of the patient, including respiratory rate, rhythm, and effort, as well end-tidal carbon dioxide and anaesthetic agent levels if the equipment is available to do so.

==End-Tidal Carbon Dioxide==
End-tidal carbon dioxide is often measured via capnometry and capnorgraphy.
*''Capnometry'' is the numerical display of carbon dioxide levels in the respiratory gas throughout the cycle.
*''Capnography'' is the graphical display of carbon dioxide levels in the respiratory gas throughout the cycle.
Capnometers are either ''sidestream'' or ''mainstream''. In sidestream capnometers, a sample line is attached to a small connector which is placed between the endotracheal tube and breathing system. Mainstream capnometer sampling chambers are small enough that they can be fitted directly to the endotracheal tube between that and the breathing system. Readings are based on absorption of infrared light by carbon dioxide.

===Capnograph===
# Phase 1 is the inspiratory baseline and indicates inspired carbon dioxide, therefore should be zero.
# Phase 2 is the expiratory upstroke and indicates the alveoli and conducting airway carbon dioxide levels.
# Phase 3 is the expiratory plateau which indicates pure alveoli carbon dioxide levels.
# Phase 4 is the inspiratory downstroke indicating the start of inspiration.

===Increases in End Tidal Carbon Dioxide===
*Impaired alveolar ventilation.
*Increased metabolism.
*Increased cardiac output.
*Rebreathing.

===Decreases in End Tidal Carbon Dioxide===
*Hyperventilation.
*Low cardiac output.
*Pronounced hypothermia.
*Failing circulation and cardiac arrest.

==Inhaled and Exhaled Anaesthetic Agents==
With some of the monitors now available it is also possible to monitor the inhaled and exhaled anaesthetic agent concentration. This allows monitoring of dosing of inhalant anaesthetics (inhaled value) and the exhaled value indicates the concentration in the circulation and brain.

@@ Line 17: / Line 17: @@
 ===Capnograph===
-[[Image:Capnograph.JPG|left]]
+[[Image:Capnograph.JPG|left|300px]]
 <center>

@@ Line 1: / Line 1: @@
 {{toplink
 |linkpage =Anaesthesia
@@ Line 8: / Line 7: @@
 |pagetype=Clinical
 }}
 ==Introduction==
 Most patients undergoing a general anaesthetic are maintained on inhalation agents and therefore in a situation where they will be connected to an anaesthetic machine. This means that with the inhalation agent, oxygen or medical air will also be delivered as well as nitrous oxide in some cases. It is important, as in any anaesthetic, to monitor the respiratory function of the patient, including respiratory rate, rhythm, and effort, as well end-tidal carbon dioxide and anaesthetic agent levels if the equipment is available to do so.

@@ Line 11: / Line 11: @@
 ===Capnograph===
-[[Image:Capnograph.jpg|Center]]
+[[Image:Capnograph.JPG|left]]
 <center>
-{| border="1" cellpadding="6"
+{| border="0.5" cellpadding="6"
 |-style="background:#B0E0E6; color:black"
 !'''Stage'''
@@ Line 24: / Line 24: @@
 |- style="background:#F0F8FF; color:black"
 |<font color=#0C1A5D>'''B''' </font>
-|Start of phase 1 - The beginning of the respiratory upstroke.
+|Start of phase 1.
 |-
 |<font color=#0C1A5D>'''C''' </font>
-|End of phase 1 and the beginning of the expiratory plateau.
+|End of phase 1.
 |- style="background:#F0F8FF; colour:black"
 |<font color=#0C1A5D>'''D''' </font>
@@ Line 41: / Line 45: @@
 |}
 </center>
-# Phase 1 is the inspiratory baseline and indicates inspired carbon dioxide, therefore should be zero.
-# Phase 2 is the expiratory upstroke and indicates the alveoli and conducting airway carbon dioxide levels.
-# Phase 3 is the expiratory plateau which indicates pure alveoli carbon dioxide levels.
+* Phase 1 is the inspiratory baseline and indicates inspired carbon dioxide, therefore should be zero.
-# Phase 4 is the inspiratory downstroke indicating the start of inspiration.
+* Phase 2 is the expiratory upstroke and indicates the alveoli and conducting airway carbon dioxide levels.
 ===Increases in End Tidal Carbon Dioxide===

@@ Line 13: / Line 13: @@
 ==End-Tidal Carbon Dioxide==
-End-tidal carbon dioxide is often measured via capnometry and capnorgraphy.
+End-tidal carbon dioxide is often measured via capnometry and capnography.
 *''Capnometry'' is the numerical display of carbon dioxide levels in the respiratory gas throughout the cycle.
 *''Capnography'' is the graphical display of carbon dioxide levels in the respiratory gas throughout the cycle.