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ASA Standards for 2011 - Capnography

ASA Standards Revised for Ventiltion

Bhavani Shankar Kodali MD

American Society of Anesthesiologists (ASA) recently updated monitoring standards for ventilation that are defined below. Details of the 'Standards' can be found at the end of this document.



In October 2010, the ASA House of Delegates approved a change to the ASA "Standards for Basic Anesthetic Monitoring".  In order to give ASA members sufficient time to comply with this change, the House also approved that implementation be delayed until July 1, 2011. Specifically,  Standard 3.2.4  under VENTILATION, METHODS was changed to read:  "During regional anesthesia (with no sedation) or local anesthesia (with no sedation), the adequacy of ventilation shall be evaluated by continual observation of qualitative clinical signs. 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." The intent is that during moderate or deep sedation (regardless of location), the adequacy of ventilation be evaluated by both continual observation of qualitative clinical signs and by monitoring for the presence of exhaled carbon dioxide.  The House of Delegates recognized that there might be rare circumstances when it was not possible to accomplish this and added the following qualifier  "unless precluded or invalidated by the nature of the patient, procedure, or equipment."


Although this is the standard of care for all anesthesiologists, It is reasonable to believe that capnography should be used by all non anesthesiologists to monitor ventilation during sedation. This is because


  • Hypoxia follows hypoventilation, or apnea and therefore capnography can recognize hypoventilation, airway obstruction, or apnea. This will facilitate corrective measures to be undertaken before the onset of  hypoxia.  
  • Administration of oxygen maintains oxygenation for a longer interval after apnea and therefore might delay detection of apnea, or hypoventilation. 
  • Relying on pulse oximeter alone can decrease the margin of safety as corrective actions are taken only when pulse oximeter gives an alarm. 
  • Non anesthesiologists may not be as adept as anesthesiologists in assisting ventilation, or intubation, when required. 
  • Many sedation procedures are performed away from operating rooms and substantial time may be required before anesthesiologists arrives for help




Committee of Origin: Standards and Practice Parameters

(Approved by the ASA House of Delegates on October 21, 1986, and last amended on

October 20, 2010 with an effective date of July 1, 2011)

These standards apply to all anesthesia care although, in emergency circumstances, appropriate life support measures take precedence. These standards may be exceeded at any time based on the judgment of the responsible anesthesiologist. They are intended to encourage quality patient care, but observing them cannot guarantee any specific patient outcome. They are subject to revision from time to time, as warranted by the evolution of technology and practice. They apply to all general anesthetics, regional anesthetics and monitored anesthesia care. This set of standards addresses only the issue of basic anesthetic monitoring, which is one component of anesthesia care. In certain rare or unusual circumstances, 1) some of these methods of monitoring may be clinically impractical, and 2) appropriate use of the described monitoring methods may fail to detect untoward clinical developments. Brief interruptions of continual† monitoring may be unavoidable. These standards are not intended for application to the care of the obstetrical patient in labor or in the conduct of pain management.


Qualified anesthesia personnel shall be present in the room throughout the conduct of all general anesthetics, regional anesthetics and monitored anesthesia care.

1.1 Objective –

Because of the rapid changes in patient status during anesthesia, qualified anesthesia personnel shall be continuously present to monitor the patient and provide anesthesia care. In the event there is a direct known hazard, e.g., radiation, to the anesthesia personnel which might require intermittent remote observation of the patient, some provision for monitoring the patient must be made. In the event that an emergency requires the temporary absence of the person primarily responsible for the anesthetic, the best judgment of the anesthesiologist will be exercised in comparing the emergency with the anesthetized patient’s condition and in the selection of the person left responsible for the anesthetic during the temporary absence.


During all anesthetics, the patient’s oxygenation, ventilation, circulation and temperature shall be continually evaluated.

2.1 Oxygenation –

2.1.1 Objective –

To ensure adequate oxygen concentration in the inspired gas and the blood during all anesthetics. STANDARDS FOR BASIC ANESTHETIC MONITORING

2.2 Methods –

2.2.1 Inspired gas: During every administration of general anesthesia using an anesthesia machine, the concentration of oxygen in the patient breathing system shall be measured by an oxygen analyzer with a low oxygen concentration limit alarm in use.*

2.2.2 Blood oxygenation: During all anesthetics, a quantitative method of assessing oxygenation such as pulse oximetry shall be employed.* When the pulse oximeter is utilized, the variable pitch pulse tone and the low threshold alarm shall be audible to the anesthesiologist or the anesthesia care team personnel.* Adequate illumination and exposure of the patient are necessary to assess color.*


3.1 Objective –

To ensure adequate ventilation of the patient during all anesthetics.

3.2 Methods –

3.2.1 Every patient receiving general anesthesia shall have the adequacy of ventilation continually evaluated. Qualitative clinical signs such as chest excursion, observation of the reservoir breathing bag and auscultation of breath sounds are useful. Continual monitoring for the presence of expired carbon dioxide shall be performed unless invalidated by the nature of the patient, procedure or equipment. Quantitative monitoring of the volume of expired gas is strongly encouraged.*

3.2.2 When an endotracheal tube or laryngeal mask is inserted, its correct positioning must be verified by clinical assessment and by identification of carbon dioxide in the expired gas. Continual end-tidal carbon dioxide analysis, in use from the time of endotracheal tube/laryngeal mask placement, until extubation/removal or initiating transfer to a postoperative care location, shall be performed using a quantitative method such as capnography, capnometry or mass spectroscopy.* When capnography or capnometry is utilized, the end tidal CO2 alarm shall be audible to the anesthesiologist or the anesthesia care team personnel.*

3.2.3 When ventilation is controlled by a mechanical ventilator, there shall be in continuous use a device that is capable of detecting disconnection of components of the breathing system. The device must give an audible signal when its alarm threshold is exceeded.

3.2.4 During regional anesthesia (with no sedation) or local anesthesia (with no sedation), the adequacy of ventilation shall be evaluated by continual observation of qualitative clinical signs. 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. STANDARDS FOR BASIC ANESTHETIC MONITORING


4.1 Objective –

To ensure the adequacy of the patient’s circulatory function during all anesthetics.

4.2 Methods –

4.2.1 Every patient receiving anesthesia shall have the electrocardiogram continuously displayed from the beginning of anesthesia until preparing to leave the anesthetizing location.*

4.2.2 Every patient receiving anesthesia shall have arterial blood pressure and heart rate determined and evaluated at least every five minutes.*

4.2.3 Every patient receiving general anesthesia shall have, in addition to the above, circulatory function continually evaluated by at least one of the following: palpation of a pulse, auscultation of heart sounds, monitoring of a tracing of intra-arterial pressure, ultrasound peripheral pulse monitoring, or pulse plethysmography or oximetry.


5.1 Objective –

To aid in the maintenance of appropriate body temperature during all anesthetics.

5.2 Methods –

Every patient receiving anesthesia shall have temperature monitored when clinically significant changes in body temperature are intended, anticipated or suspected.

Note that "continual" is defined as "repeated regularly and frequently in steady rapid succession" whereas "continuous" means "prolonged without any interruption at any time."

* Under extenuating circumstances, the responsible anesthesiologist may waive the requirements marked with an asterisk (*); it is recommended that when this is done, it should be so stated (including the reasons) in a note in the patient’s medical record.


NPR news and capnography

[4 min 37 sec]
Howard Snitzer's heart stopped beating for 96 minutes last January. First responders didn't give up on him, thanks in part to capnography, a technology that let them know Snitzer still had a chance of coming back.
Enlarge May Clinic

Howard Snitzer's heart stopped beating for 96 minutes last January. First responders didn't give up on him, thanks in part to capnography, a technology that let them know Snitzer still had a chance of coming back.

August 22, 2011

Last January, a Minnesota man's heart stopped beating for an amazing 96 minutes. Emergency room doctors thought he was dead. But first responders who gave CPR on the scene decided not to give up, in part because of technology that allowed them to see their efforts were working.

It's called capnography, and it measures how much carbon dioxide is being expelled with each breath. This information helps doctors and emergency medical personnel determine whether a patient is hyperventilating or having a heart attack. It also helps them decide how to treat an asthma attack, or determine whether CPR is working.

How It Works

At a fire station in Brook Park, Ohio, medical officers put a tube in my nose and hook me up to the machine to show me how it works.

"OK, that last data stream there is the capnography. Now just breathe normal," Lt. Mark Lynch says, pointing at a graph on the screen that moves up and down when I breathe.

I watch the monitor as I inhale and exhale. "Every time I breathe out, it goes up," I remark.

"Yes. That's the exhalation. Right," Lynch confirms.

There is also a number on the screen that corresponds to the carbon dioxide I exhale — an estimate of carbon dioxide levels in my blood. As I change my breathing, the number changes, too. By breathing rapidly, I blow out carbon dioxide, and the number on the screen goes down. If I hold my breath, it goes up. Lynch explains that if I were unconscious and receiving CPR, the carbon dioxide levels would tell them how efficiently their chest compressions were pumping blood through my lungs and to my organs. Breathing normally, my number is 35.

"Now, during good CPR, this is probably going to be around 25 — if you keep this up in that 25 range, then there's circulation still going on. ... That's where you're going to get a positive outcome," Lynch says.

Capnography is not a new technology. In fact, it's been around for years, used by anesthesiologists to monitor a patient's breathing during surgery.

But these days, the technology is making its way out of hospital operating rooms and into portable devices that are helping first responders make critical — sometimes life-saving — decisions.

Knowing When Not To Quit

That was certainly the case for Howard Snitzer when he collapsed in front of a Minnesota grocery store one cold night last January. After he woke up days later, some of the emergency medical personnel who helped that night told him what had happened.

"They said, 'We were wondering what you remember about your heart attack.' And I said, 'Nothing.' And they said, 'Well, here's what we remember.' And they started telling this story, and I was just blown away," Snitzer recalls.

For more than an hour and a half, Snitzer had no pulse. Emergency room doctors said there was nothing more they could do. But one of the flight nurses who had come with the emergency helicopter had been trained in capnography. Snitzer's carbon dioxide levels suggested that blood was flowing to vital organs like the heart and brain, and the nurse thought Snitzer still had a chance.

The nurse "called the emergency room doctor, who told him that I was dead and that they should walk away," says Snitzer. "And he hung up and he said to the rest of the people in the room, 'Is anyone else here uncomfortable with walking away from this?' And they all said yes. And it was at that point that he called Dr. White."

That's Dr. Roger White, an anesthesiologist at Mayo Clinic. He's the one who finally came up with the solution to get Snitzer's heart beating normally again.

"We just continued believing that the measurement of carbon dioxide pressure said that if we can stop that fatal rhythm, Howard will be OK," White explains.

After shocking Snitzer's heart 12 times and administering intravenous drugs, they finally did manage to stop that fatal heart rhythm. When a pulse and a regular heartbeat had been restored, Snitzer was airlifted to the Mayo Clinic.

White says that before the use of capnography, the only way of assessing blood flow to vital organs was by feeling for a pulse or by looking for dilated pupils. He says those methods are very crude and can fail. Snitzer never had a pulse despite good carbon dioxide readings. Without the information from capnography, he says, it would have been reasonable to stop CPR — and Snitzer likely would have died.

"The lesson that I certainly learn from this is you don't quit — you keep trying to stop that rhythm as long as you have objective, measurable evidence that the patient's brain is being protected by adequate blood flow as determined by the capnographic data," says White.

Capnography is slowly becoming standard equipment for emergency responders. Next year, the fire department in Brook Park will have five new capnography machines — as opposed to the one they have now.

The American Heart Association added capnography to its 2010 guidelines for treating cardiac arrest patients — a sign, says White, that it's a technology that emergency medical teams can no longer do without.

Time for capnography - Everywhere

Time for capnography - everywhere

This title is based on the editorial by DR Whitaker in Anaesthesia 2011;66:544-9 titled "Time for Capnography - Everywhere" 

Anesthesiologists have adopted capnography as a standard of monitoring in operating rooms for 25 years. Despite proven value of capnography in operating rooms, its use in outside of the operating rooms has not matched that in the operating rooms. Anesthesiologists have understood the value of capnography and pulse oxymetry 25 years ago and did not wait for randomized control studies to prove their value in clinical practice before their introduction. Due credit should be given to the anesthesiology leadership at the American Society of Anesthesiologists, Anesthesiology Association of Holland, and Association of Anesthetists of Great Britain and Ireland to implement capnography as a standard of care based on predictive conclusions of retrospective analysis.  This has probably made anesthesia safer in the operating rooms.   What about outside of operating rooms? The reasons may be many. Instead of debating on the reasons why capnography has not become a standard outside of OR / OT, it is time to implement its use now everywhere outside of operating rooms, wherever, intubations, ventilations, and sedations take place. The current evidence, based on what can considered as a controlled study comparing the outcomes with and without capnography, should decisively go in favor of implementing capnography outside of OR /OT. The data from the studies show that in 2008-9 there were 16 airway deaths from the 3 million patients undergoing general anesthesia monitored with continuous capnography, giving a death rate of 1:180,000. Similarly, there were 18 deaths from a much smaller number of ICU patients receiving ventilation: 48000 during the study year, giving a death rate of 1 in 2700. This implies that it is 66 times more likely to have airway catastrophes in ICU where capnography is not used as compared to operating room where continual capnography is the standard of care. What is more alarming is the conclusion of the study group that 74% of ICU airway deaths could have likely been prevented had continuous capnography been used. This led to several recommendations to be implemented.

 British Journal of Anaesthesia 2011;106(5):632-42

In Intensive Care Unit: 

1.Capnography should be used for intubation of all critically ill patients irrespective of location.

2. Continuous capnography should be used in all ICU patients with tracheal tubes (including tracheostomy) who are intubated and ventilator-dependent. Cost and technical difficulties may be practical impediments to the rapid introduction of routine capnography. However, these need not prevent its implemenation.

3. Where capnography is not used, the reason should be documented in the chart.

4. Training of all clinical staff who work in ICU should include interpretation of capnography. Teaching should focus on identification of airway obstruction or displacement.  In addition, recognition of the abnormal (but not flat) capnograph trace during CPR should be emphasized.  

In Emergency Unit:

1.  Capnography should be used for all intubations in the ED

2. Capnography should be used for all anesthetized patients in ED

3. Capnography should be used for intubated patients during transfers from the ED to other departments.  



96 minute of CPR with capnography

During CPR, capnography does help to gauge the effectiveness of CPR. Effective CPR can facilitate enough cerebral and pulmonary circulation. The pulmonary circulation can be indirectly monitored by capnographic waveform and end tidal carbon dioxide values. The following video illustrates the values of capnography during CPR.





CPR and Capnography

Since the current guidelines of ACLS, and AAGBI recommend capnography during CPR, we have adapted the following. The movable stand is equipped with code box, capnograph, and a Video laryngoscope for unanticipated difficult intubation when called for a code


Bhavani Kodali MD CPR and capnography