Circulation 122,210 • Volume 34, No. 2 • October 2019   Issue PDF

Anesthetic Monitoring Recommendations: How Consistent Are They Across The Globe?

Jan Hendrickx, MD, PhD
The information provided is for safety-related educational purposes only, and does not constitute medical or legal advice. Individual or group responses are only commentary, provided for purposes of education or discussion, and are neither statements of advice nor the opinions of APSF. It is not the intention of APSF to provide specific medical or legal advice or to endorse any specific views or recommendations in response to the inquiries posted. In no event shall APSF be responsible or liable, directly or indirectly, for any damage or loss caused or alleged to be caused by or in connection with the reliance on any such information.

OR MonitoringMonitoring recommendations for patients during anesthesia care are intended to increase patient safety. Professional organizations develop these recommendations to provide guidance for safe anesthesia practice. One might expect recommendations across the world to be consistent because patient safety is a universal concern for all anesthesia professionals. There are, however, important differences in the approach to patient monitoring advocated by professional societies around the world.

We compared the monitoring standards of six different organizations (presented in alphabetical order):

  1. “Standards for basic anesthetic monitoring” (American Society of Anesthesiologists, ASA)1
  2. “Recommendations for standards of monitoring during anaesthesia and recovery” (Association of Anaesthesists of Great Britain and Ireland), AAGBI2
  3. “Recommendations for minimal monitoring during anaesthesia and recovery” (European Board of Anaesthesiology, EBA)3
  4. “Guidelines on monitoring in anaesthesia” (Hong Kong College of Anaesthesiologists, HKCA)4
  5. “Code of Ethics, Standards of Practice, Monitoring, and Education” (International Federation of Nurse Anesthetists, (IFNA)5
  6. “International standards for a safe practice of anesthesia” (World Health Organization and World Federation of Societies of Anaesthesiologists, WHO-WFSA)6

These organizations were selected as a cohort representative of standards in different parts of the world. The comparison between these organizations illuminates the differences that exist and potential for reconciliation. Other professional organizations throughout the world such as the American Association of Nurse Anesthetists (AANA), and Australia and New Zealand College of Anaesthetists (ANZCA) publish monitoring standards that offer important patient safety guidance to their constituents and should be included in any efforts to reconcile the standards.7,8

“Standards”—What’s in a name?

The ASA (Table 1), IFNA, WHO-WFSA, and AAGBI include the word “Standards” in their title whereas the EBA uses “Recommendations” and the HKCA uses “Guidelines.” Further evaluation of these documents reveals nuances of language that are important to the practitioner. In particular, it is important to understand what is considered an absolute monitoring requirement for every anesthetic, versus monitoring modalities that are useful but not essential and how these distinctions are determined. Reconciling the various approaches will require agreement on the implications of the terms used.

Table 1: The ASA Policy Statement on Practice Parameters Definitions9

  • Provide rules or minimum requirements
  • Are regarded as generally accepted principles of patient management
  • May be modified only under unusual circumstances
    Are supported by meta-analyses of findings from multiple clinical trials
  • Are agreed upon by all or nearly all expert consultants and surveyed ASA members
  • Most stringent recommendation
  • Failing to comply with a standard would constitute a practice breech and not only put the patient at risk, but expose the provider to liability that would be difficult to defend if an adverse event occurred
Evidence-based practice guidelines
  • Provide recommendations that describe a basic management strategy supported by meta-analyses of multiple clinical trials
  • Are agreed upon by a majority of expert consultants and surveyed ASA members
  • Not intended to be standards or minimum requirements
Evidence-based practice advisories
  • Provide statements to assist decision-making in areas of patient care where there is not a sufficient number of adequately controlled studies to permit meta-analysis
  • Not intended to be standards or minimum requirements
The ASA Committee on Standards and Practice Parameters is one committee that supervises the creation of new and revision of practice parameters.

The EBA document defines “core standards” for monitoring as those to “be used whenever a patient is anaesthetized.”3 The WHO-WFSA uses a tiered approach. A “highly recommended” standard is considered mandatory, which, if not met, means providing anesthesia for elective surgical procedures is unsafe and unacceptable. “Recommended” and “suggested” standards should be practiced “when resources allow and if appropriate for the health care being provided.”6

Inconsistent Monitoring Requirements

Keeping in mind the “semantic modifiers” alluded to in the previous paragraph, we provide a brief review of the recommendations contained in the “standards” from these different organizations. All societies require that every anesthetized patient be continuously attended by a qualified anesthesia professional and have requirements for clinical monitoring. All require alarms to be activated and audible, with limits properly applied. There are, however, differences in recommendations for individual parameters. For purposes of this discussion, the term standard will be used to indicate an absolute requirement.


Blood oxygenation monitoring by pulse oximetry is a universal standard among all organizations. Monitoring of the inspired O2 concentration accompanied by a low threshold alarm is a standard for all except the WHO-WFSA document where it is “recommended.” Monitoring skin color is a standard for all except the AAGBI and EBA where they state it “may be included as an appropriate clinical observation.”2,3


All organizations surveyed require end-expired CO2 to be detected after intubation or supraglottic airway placement, and all but the WHO-WFSA require end-expired CO2 to be monitored thereafter. WHO-WFSA cites cost and lack of robustness as the reasons for only “recommending” continuous CO2 monitoring.6 Qualitative assessment of ventilation (movement of chest and breathing bag, auscultation) is considered standard by WHO-WFSA, IFNA, and EBA, but not by ASA, AAGBI, HKCA. Monitoring inspired CO2 concentration and cuff pressure of airway devices is considered a standard by HKCA. Standards for monitoring during mechanical ventilation differ: ASA “strongly encourages” and WHO-WFSA “suggests” expired volume to be measured1,6; all but ASA, IFNA and WHO-WFSA consider airway pressure monitoring a standard; and a disconnection detector with alarm is a standard for all except the WHO-WFSA which “recommends” it.


Electrocardiogram (ECG), intermittent blood pressure measurements, and heart rate monitoring are consistent standards, except for the WHO-WFSA who only “recommends” ECG for rhythm monitoring. In the AAGBI and EBA guidelines, heart rate monitoring is present implicitly in the ECG and pulse oximetry monitoring requirement. All guidelines require confirmation of a pulse (i.e., mechanical activity resulting in cardiac output) in the form of at least one of these: 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. The AAGBI and HKCA standards require a stethoscope “be available.”


Temperature is not advocated as a standard to be adhered to throughout the entire procedure by any of the organizations. Recommendations are inconsistent and range from “a means to measure temperature has to be available” to “recommended” to “essential for procedures > 30 min,” to “when clinically significant changes in body temperature are intended, anticipated or suspected.”

Kidney function

Monitoring urine output is either not mentioned, or “suggested in appropriate cases” (WHO-WFSA, AAGBI).

Neuromuscular blockade monitoring after administration of muscle relaxants

Recommendations range from being a standard (AAGBI) to not being mentioned (ASA) to variations in between. For example, the WHO-WFSA “recommends” it, the EBA states that a nerve stimulator has to be available, and the HKCA states that “it should be used whenever the anesthetist is considering extubation following the use of non-depolarizing neuromuscular blockade.”3,4,6 The IFNA states that professionals should “measure, assess, and score neuromuscular function by a neuromuscular monitor (if available) when neuromuscular blocking agents are being used.”5

Concentration of inhaled anesthetics

Monitoring the end-expired concentration of inhaled anesthetic agents is a standard for the AAGBI, EBA, and the HKCA (the latter, in addition, requires automated agent detection). The WHO-WFSO “suggests” both inhaled and exhaled concentrations be measured.6 The IFNA recommends that both inspiratory and expiratory anesthetic concentrations of volatile agents be measured continuously “if possible.”5 The ASA standards do not mention inhaled anesthetic agent concentration monitoring.

Measure of drug effect on the central nervous system/unconsciousness

According to the HKCA, “equipment to monitor the anaesthetic effect on the brain should be applied, especially for patients at high risk of awareness, for example, those receiving total intravenous anaesthesia with a muscle relaxant.”4 The IFNA states that the application of an electronic device intended to measure cerebral function, particularly in cases with high risk of awareness under general anesthesia should be “considered.”5 The WHO-WFSA states that its “use… while not universally recommended or used, is suggested, particularly in cases at risk of awareness under general anesthesia or postoperative delirium.”6 The AAGBI recommends the “use of depth of anaesthesia monitors, for example processed EEG monitoring…when patients are anaesthetised with total intravenous techniques and neuromuscular blocking drugs, to reduce the risk of accidental awareness during general anaesthesia. However, there is no compelling evidence that routine use of depth of anaesthesia monitoring for volatile agent-based general anaesthetics reduces the incidence of accidental awareness when end-tidal agent monitoring is vigilantly monitored and appropriate low agent alarms are set.”2 According to the EBA, “their routine use has yet to be fully considered as part of our recommended minimum monitoring standards.”3 ASA does not consider EEG or EEG-derived indices in its Standards for Basic Anesthetic monitoring.

This brief review has identified a number of inconsistencies between the anesthesia monitoring recommendations promoted by professional organizations in different parts of the world. In general, monitoring standards for parameters that describe the cardiopulmonary system are mostly consistent. This is less true for other physiological systems or for other aspects of the anesthetic state like immobility or unconsciousness.

If safety is universal, why are recommendations not?

Published recommendations are developed by consensus within each organization, so it is not surprising that the results are different around the world. For the developing world, professional organizations are sensitive to resource limitations and are reluctant to impose requirements that are difficult to comply with. Nevertheless, the importance of patient safety does not change by geography. The WHO-WFSA has made a major effort to reconcile guidelines by different societies and develop practical recommendations that can be followed anywhere in the world. In the developed world, the differences in recommendations are more difficult to understand since the resource constraints are not as significant.

Which important recommendations might merit reconciliation?

The recommendations for end-expired agent monitoring and anesthetic depth monitoring are different from each organization yet can be important tools for assessing anesthetic effect and should be considered when thinking of aligning the various recommendations. During surgery under general anesthesia, the patient expects to be unconscious and to not experience pain.10 Both inhaled and intravenous agents are commonly employed to achieve that goal. When inhaled agents are used, end-expired anesthetic agent monitoring can insure that the inhaled anesthetic agent and appropriate dose are being delivered. As noted above however, only three organizations of those reviewed consider end-expired agent monitoring a standard. WHO-WFSA “suggests” that it be used whereas the ASA monitoring standard does not even mention inhaled agent monitoring. When intravenous agents are used, we cannot assess the serum concentration quantitatively so we are left with measures of drug effect such as processed EEG. Despite the technology limitations of processed EEG monitoring, more than one organization (but not all) advocates that it be used, especially for patients at high risk for awareness.

The primary responsibility of the anesthesia professional is to keep the patient safe. Resources, liability concerns, patient needs, and clinical scenarios all play a role in determining the monitoring needs for any given patient. Standards are essential to patient safety and we should seek to insure they provide common protections for all patients no matter where they live.


Across the globe, anesthetic monitoring standards for parameters that describe the cardiopulmonary system are mostly consistent. For other physiological systems or for other aspects of the anesthetic state like immobility or unconsciousness, this is less true. In related articles in this issue, Jin, Gan, and Feldman review the capabilities and limitations of EEG-based anesthetic depth monitoring to assess the potential for this technology to become a standard.


Drs. Philip and Hendrickx consider whether inhaled agent monitoring should be considered a standard.

Dr. Hendrickx is a staff anesthesiologist at OLV Hospital, Aais, Belgium.

Disclosure: Dr. Hendrickx has received lecture support, travel reimbursements, equipment loans, consulting fees, and meeting organizational support from AbbVie, Acertys, Air Liquide, Allied Healthcare, Armstrong Medical, Baxter, Dräger, GE, Getinge, Hospithera, Heinen & Lowenstein, Intersurgical, Maquet, MDMS, MEDEC, Micropore, Molecular, NWS, Philips, Piramal, Quantium Medical.


  1. Standards for basic anesthetic monitoring. Committee of Origin: Standards and Practice Parameters. Approved by the ASA House of Delegates on October 21, 1986, last amended on October 20, 2010, and last affirmed on October 28, 2015.
  2. Checketts MR, Alladi R, Ferguson K, et al. Recommendations for standards of monitoring during anaesthesia and recovery 2015: Association of Anaesthetists of Great Britain and Ireland. Association of Anaesthetists of Great Britain and Ireland. Anaesthesia. 2016;71:85–93.
  3. European Board of Anaesthesiology (EBA) recommendations for minimal monitoring during anaesthesia and recovery. UEMS Anesthesiology Section, European Board of Anaesthesiology (EBA). Accessed May 7, 2019.
  4. Guidelines on monitoring in anaesthesia. Version 5, May 2017. Document No. HKCA—P1—v5. Prepared by College Guidelines Committee. Endorsed by HKCA council. Next Review Date 2022. Accessed May 7, 2019.
  5. International Federation of Nurse Anesthetists (IFNA). Standards of education, practice, and monitoring. Accessed August 2, 2019.
  6. Gelb AW, Morriss WW, Johnson W, et al. World Health Organization-World Federation of Societies of Anaesthesiologists (WHO-WFSA) International Standards for a Safe Practice of Anesthesia. International standards for a safe practice of anesthesia workgroup. Can J Anaesth. 2018;65:698–708.
  7. American Association of Nurse Anesthetists (AANA). Standards for nurse anesthesia practice. Accessed June 10, 2019.
  8. Australia and New Zealand College of Anaesthetists (ANZCA). Recommendations on monitoring during anesthesia. PS 18, 2013. Accessed July 2, 2019.
  9. American Society of Anesthesiologists (ASA). Policy statement on practice parameters. Approved by the ASA House of Delegates on October 17, 2007, and reaffirmed on October 17, 2018. Accessed June 10, 2019.
  10. Tononi G. Consciousness, sleep, and anesthesia. John W. Severinghaus Lecture, ASA annual meeting, 2011. ASA Accessed May 24, 2019.