Technology and Anesthesia Outcome



Technology encompasses every part of our life and our profession is no exception. Technology has immensely influenced the growth of anaesthesia and contributed significantly to patient safety and quality of care. This article attempts to 1) review and summarize how the technology in and related to anaesthesia has advanced over the last several decades, 2) outline its effects on outcome of anaesthesia and 3) future directions of technology applications in anaesthesia.

October 16th demonstration of anesthetic effects of ether in 1846 can be considered as the birth of anaesthesia as a specialty. To begin with it was a very simple and primitive (at least as we see now) aspect of medical profession, being managed by non-doctor paramedical professionals (nurse anesthetists in USA) for several decades to follow. For long time (still probably continuing in some parts of the world), the surgeon himself used to anaesthesia and then operate. The professional work consisted of only few techniques and drugs. There was hardly any instrument-based monitoring. Anesthesia delivery began as a Schimmel Busch Mask and then the Boyles machine was introduced. It is interesting that the word “Boyles Machine” continues to be used for any anesthesia machine or even workstation by non-anesthesiologists including our own surgeon colleagues.

Practice of anaesthesia is both an art and science where a right mix of theory knowledge and technical proficiency is needed for best outcome in terms of safety and quality. Anaesthesia is not an exact science in the sense that several aspects of anaesthesia, especially how general anaesthesia is produced and maintained, are yet to be fully elucidated. Advances in surgery which enabled the surgeon to perform more and more variety and complex procedures on more sick patients for longer duration. Technology has a played vital role in enabling the anesthesiologist to deliver a better care and encompasses every aspect of profession.

The safety of patients, as demonstratable by lack of morbidity and mortality, providing ideal conditions for surgery and comfort of the patient are the important goals of anaesthesia, probably in the same order of importance. The care begins with preoperative period, continues during the surgery and ends in the postoperative period. Perioperative care includes the entire period of care from the preoperative phase to discharge from postoperative ward. This includes a) preoperative assessment b) preparation c) administration of anaesthesia (drugs, techniques), d) monitoring e) pain management f) anticipation, prevention recognition and management of complications and g) performing lifesaving procedures. In addition, modern anaesthesia practice involves adhering to protocols (institutional, departmental) and guidelines (national, international), processes, documentation etc.

 Today, and increasingly more in future, anaesthesiologist is likely to work as a member of a multidisciplinary team specializing in certain type of surgery or procedure his/her roles being extended to intensive care, pain management, trauma care, disaster management and resuscitation trainer. At every stage clinical knowledge and skills are important. Along with skills and knowledge technology has played a significant role in achieving the objectives of safe outcome. Technology has helped to identify high risk patients, monitor them better so that complications or susceptibility to complications can be detected early, manage complex high-risk patients and provide better care to patients.


Technology: what has changed over the decades?

Virtually every aspect of patient care has been influenced by technology, directly and indirectly. Direct benefit is in terms of various equipment (ranging from hypodermic needle to most advanced workstation or monitors) and indirect are through the development of supporting equipment, drugs, data, concepts, guidelines etc. Training and learning also have been benefitted by technology, starting from models to simulation. The development of new technology and refinement of existing technology has been consistent and has resulted in better quality, reliability and safety.

It is not possible, nor is the purpose of this article, to discuss individual new technology as it is worth of a complete textbook. The advancement of technology can be reviewed under the following categories:

Invasive monitoring to noninvasive (or minimally invasive) and intermittent to continuous.

Invasive monitoring, especially of hemodynamics like central venous pressure or pulmonary capillary wedge pressure, though have been very popular and considered as gold standard for many decades, is associated with disadvantages related to techniques, sterility, contraindications, difficulty in interpretation, delay in establishing the monitor leading to risk of complications in the patients.  

Noninvasive monitors have reduced or eliminated the risks of invasive techniques while progressively being more accurate and reliable. They are easy to set up, user friendly, painless and started pre induction. Continuous display of graphs and values help to minimize complications and reduce dependence of laboratory values

  1. Use of pulse oximetry and capnogram, often referred to as the “dynamic duo” of monitoring, is considered as inflection points in the development of anaesthesia practice. They have obvious and indirect influence on reducing complications and their applications have widened into all critical areas of patient care. The disadvantages of pulse oximetry have been overcome with cerebral oximetry and co oximetry. With the latter, carboxyhemoglobin and methemoglobin can be detected and monitored.
  2. Cardiac function can be monitored continuously by noninvasive techniques like advanced electrocardiogram, transesophageal echocardiography and cardiac output (CO) monitors. With conventional and 3D monitoring it possible to monitor valvular function, ventricular filling, myocardial contractility and other hemodynamic parameters real time.
  3. Neurological monitoring has been achieved by transcranial doppler, cerebral oximetry, more refined electroencephalogram and electrocorticogram (semi invasive), regional blood flow measurements, depth of anaesthesia (bispectral index and entropy) and evoked potential (motor and sensory) monitoring.
  4. Other noninvasive monitors include continuous hemoglobin monitoring, sedation monitors, acceleromyograph, thromboelastographic and continuous respiratory monitoring.
  5. Use of ultrasound for airway management and diagnosis of perioperative life-threatening complications like pneumothorax and for regional anaesthesia.

Fixed to customizability and portability

1)New monitors or equipment allow plenty of options and combination of parameters for the anaesthesiologist to choose from enabling management of patients with complex medical conditions. This has been possible by

  1. Modular concept: groups of specific parameters are presented as different modules (metabolic module, neuromuscular module, anesthesia gas module, etc.) enabling the user to choose the combination of parameters most suitable for the given patient.
  2. Better user interfaces with flexibility in monitored and set parameters, graphic and loop formats.
  3. Better battery backup and portability
  4. Slave monitors so that they can be kept in different locations
  5. Integration of monitors with the anaesthesia workstations
  6. Common platform for different equipment likes in case of C MAC video laryngoscope, Flexible Video Endoscope

2) Anesthesia workstations with choices regarding gases, modes of ventilation, integration with other equipment like infusion pumps, advanced sophisticated vaporizers, to name a few.

3) Decrease in the size of equipment to fit into palm or easy to carry equipment. Portability is also enhanced by use of battery as the power source.

Manual to Automation – “Complex inside, simple outside”

Manual settings though are relatively simple, keep anesthesiologists’ hands occupied. Automation has made the job of anaesthesiologist/technician easy as far as setting up of equipment and handling is concerned, easy. Automation includes calibration, integration of different values monitored, detection of malfunction and errors. All the modern anaesthesia workstations monitors and several other equipment have self-testing facility. Because of automation, even if the structure and software of the equipment are complex, at the user end it remains simple.

As early as in 1950, Bickford attempted automation to maintain anesthesia using an equipment utilizing summated electroencephalographic signals. Unfortunately, even after nearly 70 years later, the dream is far from being realized though there has been much progress. This is because there are multiple domains involved in the production (hypnosis, analgesia, muscle relaxation), maintenance and recovery from anaesthesia. Each of them individually must be understood and close loop systems and finally all the domains related close loop systems must be integrated into the designing of a machine.

Enhanced safety, reliability and accurate

Modern technology has reduced the errors and problems inherently associated with the equipment earlier. The values and parameters measured are more accurate and less subject to influence or interference by extraneous nonclinical factors. Reliability of function of equipment over a wide range of clinical situations. The accuracy measurement of equipment follows established standards. Examples:

  • Reduced impact of external light, motion, nail polish and poor perfusion on oximetry measurements
  • Micro stream capnogram
  • Anesthesia workstations : a) reliability over a wide range of age, weight and flow rates b) adequate and safe ventilation of patients with diseased lungs by choosing appropriate mode c)hypoxia prevention, even at low flows d) efficient and reliable closed circuit system e) Extensive but customizable alarm systems f) autocalibration and g) Advanced vaporizers delivering accurate output without being affected by temperature, pressure, fresh gas flow etc
  • Accurate measurement of depth of neuromuscular blockade, rapid set up of monitors and ultrasound devices and ability to differentiate between oxygen and carbon monoxide using oximetry.

Hands on learning to simulation-based learning

It’s impossible to train in all the techniques and complexities involved in the practice of anaesthesia on the patient. This is both because of ethical considerations and the potential risks for the patients. Rarity of certain lifesaving procedures and the need for them to be successful when required make the task more difficult.

Advantages of simulation-based learning

  1. No harm to patient and no ethical consideration
  2. Skill can be practiced to perfection, to achieve set target points
  3. No risk of infection
  4. Rarely performed procedures and skills can be learnt
  5. Teamwork and communication
  6. Accurate and objective assessment possible
  7. Training in crisis management
  8. Useful for training paramedical professionals as well

One specific purpose-oriented technology in simulation is a novel approach to learning anatomy using HoloLens. It is an augmented reality system in which the wearer interacts with a digital model which in this case is a w-D anatomical model. This was built using actual MRI data of real patients. It has enormous flexibility such as ability to add or remove tissue layers in a virtual environment and distance learning where the instructor could be far away from the location of training.

Handwritten documentation to paperless or electronic data base

Anaesthesia data is an important source of information and is a vital medicolegal document as well. Shifting to paperless electronic documentation leads to accuracy, indestructability, prevention of subsequent manipulation and remote accessibility. Patient records are important sources of medicolegal investigations and clinical research as well.

Data sharing and big data

Logical consequence of collection of enormous data in an electronic and digital form has been generation of a large pool of scientific data across the world. With the advances in software, it is possible to share these data and analyze them to recognize various pattern and extract lot of information about various aspects of anesthetic management including patient responses to medications, prediction of complications etc.

Clinical early warning algorithm is an example of use of big data, to detect early onset of clinical deterioration in anaesthesia.

Medication and blood management

Medication error is an important preventable error related to medicine in general and anaesthesia. Technology has helped in several ways in this regard.

  1. Bar coding of drugs
  2. Color coding of syringes
  3. Prefilled syringes
  4. Advanced infusion technologies like target-controlled infusion with various formula and algorithms and in-built safety mechanisms
  5. Recombinant drugs and blood components
  6. Drugs with novel pharmacokinetic and dynamic properties like atracurium, adenosine etc.



Table: Some exciting technologies that have been incorporated in anaesthesia practice (representational examples, affecting different aspects of anaesthesia practice)


Preoperative phase


1.       Virtual bronchoscopy

2.       Ultrasound for preoperative diagnosis, identifying difficult airway

3.       Cardiopulmonary testing and maximum oxygen consumption VO2

4.       Intranasal routes of drug delivery



Intraoperative phase


1.       Advanced anaesthesia workstations

2.       Airway devices: Video laryngoscopes, flexible video endoscopes, Blue Dolphin Cricothyrotomy sets, Jet ventilators, High Flow Nasal Oxygen delivery devices, Supraglottic airway devices, Micro cuff tubes

3.       Monitors: 3D Echo, co oximetry and cerebral oximetry, continuous hemoglobin and total oxygen content, cardiac output from the arterial line (Flowtrac), transthoracic doppler, transesophageal echo, somatosensory evoked potential monitoring, Cardiac enzyme monitoring, acceleromyograph, TOF Watch,  depth of anaesthesia and sedation monitoring

4.       Different types of catheters for regional anaesthesia, central neuraxial blockade

5.       Drug administration systems including infusion pumps and closed loop administration (Artificial pancreas)

6.        Drugs with novel properties like desflurane, sugammadex, atracurium, esmolol, remifentanil etc.

7.       Lifesaving equipment like implanted cardioverter devices, pacemakers, biphasic defibrillators, intraaortic balloon pump, ventricular assist devices, extracorporeal membrane oxygenators, cell savors





Data management and Artificial intelligence applications


1.       Electronic data bases like Anaesthesia Information Management System (AIMS). One of the components called Anesthesia H& P which can help in planning and conducting anesthesia with minimal risks.

2.       Digital support system (DSS) or clinical decision support system (DSS) works in conjunction with AIMS. It maintains balance and integrity of data in relation to perioperative care. Requires good networking for smooth functioning. It helps to minimize errors, of equipment and human errors and improves quality of service. Delay in feeding the data, omission of data, wrong entries and latency in management of data can significantly restrict the usefulness of data

3.       Multicenter Perioperative Outcomes Group and Anesthesia Quality Institute: A project to pool data from AIMS from multiple centers across the nation for research purposes with the final objective of improving anesthesia delivery systems.







Limitations of technology

Yes, technology has contributed to progress of our specialty and safety of patients undergoing surgical procedures. Yet, there are several limitations associated with adoption of technology.


In developed countries its essential to comply with the recommendations of professional bodies and federal agencies for the equipment or use of technology. This ensures uniform availability of technology across the country with assured quality. Equipment manufactures also must strictly adhere to quality standards.

Unfortunately, elsewhere worldwide, availability of advanced technology is limited and highly variable, both in type and variety of equipment and quality. This is supposedly due to financial considerations as anaesthesia dept is never considered as profit making (directly at least) and priority is accorded to surgical departments. Even in a developing country like others this is true.


Even if an equipment is available in institutions, it is not available to all those who would like to use, due to various reasons. This leads to reduced interest to use, and suboptimal utilization when it is occasionally used.


More advanced the equipment more likely the inability of a section of professionals to adopt to the same either because it requires additional training, repeated practice and processes like calibration, sterility etc. Or it can be simply due to aversion (“it is not technology but clinical experience which is more important”, “I don’t need all these” kind of attitudes) to technology.


Many equipment are prone for errors and artefacts. This puts a question mark on accuracy of the parameters. Use of ow quality hardware, connections, spurious software, complicated interfaces etc are some of the reasons.


False alarms, delay in booting or starting, long time gap for trouble shooting, repeated malfunction can result from poor quality hardware and software. Newer technology has reduced these problems significantly. Necessity for the equipment manufacturers to adhere accepted standards has also contributed to this positive change.

Human factors

Human factors can make a significant difference to the outcome of anesthetic management independent of the technology available. Dedication, interest in profession, knowledge and skills, good communication and team working (soft skills) and adherence to established rules of practice can improve outcome even when the technology used is not very advanced or sophisticated. A casual approach, failure to assess the patient, medication errors, burn out or fatigue, excessive stress, inadequate knowledge of equipment and poor soft skills can negatively affect outcome even in the presence of best of technology.


II Anaesthesia outcome

Outcome is an important parameter for individual professional, institutions, governments and the communities at large. Afterall, any surgery or anaesthesia is intended to improve the outcome. It is the measure of change that has taken place in individual’s physical emotional and mental status as a result of intervention. Anaesthesia mortality has been steadily coming down from 1in 1000 in 1940s to 1 in 10000 in 1970s to 1in 100000 in early 2000s. It is humanly impossible to achieve 0 mortality, but possible to reduce morbidity. It can be broadly stated that technology has contributed to better outcome after anaesthesia.

This has been achieved by

  • Improved preoperative assessment, risk stratification, rehabilitation and preparation of patients
  • Availability of safe (rather extremely safe) drugs
  • Use of versatile, reliable equipment for anesthesia administration and monitoring
  • Adjunct devices like warmers, infusion pumps, defibrillators, ventricular assist devices, extracorporeal membrane machines and other devices.
  • Use of technology at a larger level of integration of care, setting goals and objectives at the institutional, national and international levels
  • Protocols and guidelines to minimize the chance of errors and to be able to consider different options in a systematic way
  • Concepts like bloodless surgery and enhanced recovery after surgery (ERAS)
  • Reduction in transfusion related morbidity and mortality
  • Adoption of technology and developing processes to reduce medication errors
  • Automated anaesthesia information management system and clinical decision support systems
  • Multidisciplinary approach whenever required
  • Patient involvement in decision making and feedback
  • Improved postoperative care and intensive care support

Technology has played a significant role in each and every aspect mentioned above.

Types of outcome

  1. Mortality: Incidence, causes
  2. Morbidity: Type, pattern, incidence, causes
  3. Quality of care provided at the individual, department and organizational level
  4. Critical incidents
  5. Sentinel events
  6. Never events
  7. Medication errors
  8. Patient satisfaction

Outcome has also been viewed as process outcome (example: number of surgical patients rescheduled, duration of fasting, compliance with preoperative instructions etc.)  and clinical outcome (mortality, morbidity, adverse drug event).

Measuring the quality of medical care is the most complex and is further complicated by lack of agreement about terminology and definitions. Indicators of quality can be descriptive, prescriptive or proscriptive.

Sources of outcome data

1.Individual anaesthesia records, paper based or more advanced, electronic and digital data. Anaesthesia Information Management System (AIMS) is an example.

  1. Administrative records
  2. Mortality registers
  3. Data bases: Danish Airway Database (DAD), closed claims data base of ASA are some examples
  4. National registries

6.Clinical audits

When the data collected at different levels from different institutions over a long period of time becomes what is called Big Data. When used appropriately with proper statistical and epidemiological tools it becomes a good source of outcome studies.

Impact of outcome

Outcome study is used in different ways to finally achieve best and uniformly high-quality health care to all. This is possible only when the deficiencies at the various levels of healthcare are identified. The shift has been from centrally driven process targets like mortality and morbidity statistics to focus on delivering outcomes that matter most to people (Patient reported outcome measures, PROM).

Findings of outcome data can be used to improve patient care, frame/change guidelines and protocols, process and system improvements, develop training program and research among other innumerable potentials.




III Future of technology applications.

It is both exciting and challenging for the professional. Whatever technology comes to medical field slowly or rapidly enters anaesthesia as well.

1)Artificial intelligence (AI) and Machine learning (ML)

Artificial intelligence is classified as narrow or general or alternatively weak vs strong. Current AI systems are by and large week, meaning that their abilities are limited. Machine learning is a subtype of artificial intelligence whereby a computer is programmed in such a way that it gains the ability to learn the new information that it was not “explicitly programmed to learn and make changes to to its function based on what it has learned. Because of this, when the machine is given access to both the publications and real-time patient data, it can establish connection between the structured and unstructured data and able to use new data as it becomes available.

Clinical Decision Support (CDS) tools is one of the applications of ML. This along with further changes in Anaesthesia Information Management System (AIMS) are expected to further contribute to improvement in healthcare system.

2) Xenon, the future general anesthetic.  Xenon, with its unique physical and pharmacological properties comes to very close to be an ideal anesthetic for general anaesthesia. More widespread use is likely as the cost is reduced.

3)Smart Pumps and computer-controlled drug infusion delivery. These devices incorporate drug libraries and dose error reduction systems that intercept errors. Novel algorithm-based computer control has been found to reduce temporal lag in carrier and drug flows which have potential to cause clinical problems.

4) Integrated Information Displays of all the equipment like monitor, ventilator and infusion pumps could reduce the reaction time and the error of misinterpretation or chances of missing the information.

5) Smartphones and mobile devices

Applications include a pulse oximeter inbuilt into smart phone, different apps for specific purposes like patient feedback, ability to measure blood sugar non-invasively and smart phone electrocardiogram are examples. These are expected to be low cost high accuracy screening, monitoring and diagnostic tools which can be used remotely. Home screening of patients with sleep disordered breathing using smartphone incorporated pulse oximeter is an example.

Distraction of children during induction using smartphones was favorably compared with midazolam premedication in a study. Apps dealing with perioperative crisis resource management and education apps are also available online for download.

6) Tele anaesthesia

Tele anaesthesia is an emerging offshoot of telemedicine. It has been shown that communication between anesthesiologists using telecommunications among operating rooms can increase productivity according to a study in Anesthesia and Analgesia. A Japanese case report deals with using telemedicine to direct and guide anaesthesiologist in a remote island for anesthetic management using dedicated high-speed internet lines. Telemedicine, synchronous type enables stable high-speed transmission of data and exchange of information between medical professionals who are geographically far apart from each other. With further refinement in technology teleanaesthesia might help to improve quality of care in remote areas.


7) Robotic anaesthesia systems

It is a matter of time that robots will be able to assist anaesthesia management in various capacities though full conduct of anaesthesia process replacing anaesthesiologist is not realistic for next few decades at least. At present robotic intubation system using Pentax video laryngoscope, Kepler intubation system is under evaluation since 2012.Similarly first robotic ultrasound guided nerve blocks were performed using the Magellan system in 20

8) Serious gaming

This is a simulation related technology wherein entertainment and education simultaneously take place. Here multiple participants can interact from different places and performance is automatically scored without instructor being required.

An example of this approach to learning and training is American Society of Anesthesiologists Difficult Airway Algorithm and Rescue Cricothyrotomy (DAARC) game. Here multiple scenarios of airway management are built in including difficult and failed intubation. Participant can walk through these multiple scenarios and perform all the airway techniques and repeat them if required. The usefulness of this approach in its current format is yet to be clinically validated. A further refinement wherein this is combined with face to face interaction with instructor is expected to enhance the effectiveness of learning.

10) Artificial blood. Ever since blood transfusion started blood has been in short supply worldwide and there are significant potential risks of transfusion, as every anaesthesiologist is aware of. Efforts to develop an alternate to blood, primarily as oxygen carrier, were started more than 40 years ago. Still it has not reached a stage of universal acceptance and availability. Perfluorocarbon based solutions and hemoglobin-based solutions are two categories under consideration as oxygen carrier. Hemopure is a commercially available hemoglobin based oxygen carrier. So far around 2000 patients have been treated with this worldwide. Some clinical trials, however, have found hemopure to be associated with significant risk of renal and other organ toxicity.

Erythromer, is a artificial red blood cell with synthetic hemoglobin sourced from old blood. This can be freeze-dried and stored at room temperature to be reconstituted instantly when needed. Nanotechnology advances are behind the renewed interest and promising results in this field.

 10) Intravenous oxygen(IVO2) The search for an alternate to blood for oxygen delivery to tissues has not been clinically successful even after decades of research.  A novel method involving intravenous administration od a physiological solution in which oxygen is dissolved at hyperbaric concentrations. Future may see IVO2 becoming available clinically.




1) Technology has contributed significantly to the progress of anaesthesia

2) Human factors are often neglected and can contribute to problems even when the most advanced technology is used

3) Technology has affected the outcome measures, system working and integration as much as the individual care

4) Artificial Intelligence, machine learning and Big data

4.Future technologies look exciting and anaesthesiologist has responsibility to raise to the challenges and make best use of the same.




  • A low cost, customized anaesthesia information management system: An evolving process. Mridul Dhar et al, Indian Journal of Anaesthesia (2016), Vol 60: 7; 512-55
  • Anesthesiology, automation and artificial intelligence. Proceedings (Baylor University Medical Centre)
  • Advances in anesthesia technology are improving patient care, but many challenges remain. D. John Doyle et al, BMC Anesthesiology, 2018 18:39
  • Technological advances in anesthesia practice: Role of decision support system. Sukhminder Jith Singh Bajwa, Anesth Essays Res. 2014 Jan-Apr; 8(1): 117-118
  • Anesthesiology: From Patient Safety to Population Outcomes: The 49th Rovenstine Lecture Anestehsiology 4 2011. Vol. 114. 755-770
  • Measuring and recording outcome. P. J. Murphy British Journal of Anaesthesia Vol 109, Issue 1, July 2012, 92-98
  • Technology Advancing Perioperative Outcomes. Updates from the Society for Technology in Aaesthesia Annual Meeting 2017 Jonathan P Wanderer
  • Hemmerling TM,et al.First robotic tracheal intubation in humas uusing Kepler intubation system. Br J Anaesth. 2012; 108(60;1011-6
  • Hemmerling et al First robotic guided ultrasound nerve blocks in humans using the Magellan system.Anesth Analg.2013;116(2);491-4sss
  • Anesthesiology: From patient safety to population outcome. Kevin K. Tremper, The 49th Rovenstine Lecture. Anesthesiology, V 114.No 4


Leave a Reply

Your email address will not be published. Required fields are marked *