15 COVID-19 and Anesthesia




Introduction


The role of anesthetists in acute healthcare has expanded significantly in recent decades from being originally a theater-based specialty to one now that has a broader basis in provision of services in out-of-theater locations, e.g., radiology and cardiac suites as well as critical care and transport medicine.1 In spite of this, the role of the anesthetist is often underrecognized by the public and patients.24 Even within the healthcare environment, the differentiation between the anesthetist and the intensivist is often unclear.1,5 This is possibly due to the fact that these multiskilled clinicians often work in both these roles. The COVID-19 pandemic demanded many changes in the provision of anesthesia as well as where anesthetist provided their services. In this chapter we hope to provide the reader with insight into the changes on how anesthesia provision has changed during the pandemic as well as illustrate the role of anesthetists in these changes.


Anesthetists were required for safe and effective perioperative care of patients with COVID-19 as well as played significant roles in informing staff (AoA),6,7 patients (CPOC),8 and policy makers9 on how to deal with this pandemic and its aftermath.


Anesthesia nontechnical skills or similar systems1012 are now part of many training programs, providing anesthetists with tools and experience in situational awareness, decision-making, teamworking, and leadership abilities to manage the tasks and challenges of the COVID-19 pandemic.



Preoperative


Anesthetists as part of the perioperative team played a central role in the development of local and national escalation plans including updating those as new information became available (AoA).1315 Pathways for emergency, urgent, and elective surgery for COVID-19 positive (or unknown) and COVID-19 negative patients, frequently referred to as “red and green” pathways, were established. In many hospitals, states, and even countries nonurgent surgery was postponed during surges.15 This was to prevent unnecessary exposure of patients to the high-infection-risk hospital environment and to allow redeployment of staff for escalation capacity.


Information and advice provided to patients and relatives during preoperative assessments, often via phone or telemedicine, played a large role in ensuring adherence to preop isolation recommendations, screening guidelines, as well as relieve patient concerns around attending for surgery during the pandemic. This guidance was needed to protect patients from COVID-19-associated mortality, prevent transmission between patients, as well as protect staff so that services could be maintained.


An early meta-analysis revealed that perioperative mortality, complication, and rate of ICU admission among surgical COVD-19 patients were very high. Up to one death for every five COVID-19 patients undergoing surgical procedures were found.16


Strategies to decrease perioperative mortality included provision of lower risk anesthetic techniques and alternative management other than surgical procedures.



Intraoperative Management


The anesthetic management of patients during the COVID-19 outbreak had to adapt. Changes to routine practice included among others training in infection control and donning and doffing personal protective equipment (PPE), minimizing staff numbers in theaters, and performing procedures whenever possible under regional techniques.17 Specific changes to airway management with the aim to decrease aerosol generation were recommended.


Initial recommendations were based on experiences gained during SARS and MERS outbreaks which found an odds ratio between HCWs exposed to and not exposed to AGPs for risk of transmission of SARS-CoV-1 during tracheal intubation, tracheostomy, and suction before intubation to be as high as 6.6, 4.2, and 3.5, respectively.18


Throughout the COVID-19 pandemic the message has been that HCWs who perform airway management (e.g., bag-mask ventilation, tracheal intubation and extubation) are at risk of viral infection from contact, droplets, and aerosol spread.19


This as well as the limited supply of PPE resulted in clinicians designing and using physical barriers, e.g., plastic sheets or hard plastic intubation boxes in an attempt to provide an additional barrier to infection. Their use was short lived after Emergency Use Authorization by the U.S. FDA was withdrawn after concerns that these devices actually made intubation more difficult and that operating room airflow may be interrupted by these barriers.2022


Subsequent recommendations are continuously updated as more evidence becomes available.23,24 Recent publications of contrasting evidence about aerosol generation during airway management are generating considerable debate.25,26 The occupational risk has been found to be lower for those working in UK anesthesia and ICUs6 compared to other front-line workers.2729 There are many potential reasons for this and will require further research. Reasons put forward include availability of PPE, experience in infection control precautions, well-ventilated environments of theaters and ICUs, frequency of droplet and aerosol generation events on wards occurring more commonly than AGPs in operating theaters and ICUs, and the secretions of viable virus that rapidly decreases after 9 to 10 days.30


Initial data around protection afforded by vaccinations are encouraging but hasn’t yet resulted in significant change in recommendations.


Current advice continues to be based on social distancing, diligent compliance with hand washing, strict adherence to PPE protocols, as well as the use of intubation and extubation checklists.


Specific recommendations for airway management remain in place: insertion of HEPA filters at Y-piece of breathing circuits, optimal preoxygenation before induction with tight seal facemask to reduce risk of hypoxemia, positive pressure bag-mask ventilation after induction to be avoided unless the patient experiences oxygen desaturation, and minimize disconnections of breathing circuits. For optimal intubating conditions, patients should be anesthetized with full muscle relaxation. Videolaryngoscopy is recommended as first-line strategy for airway management. If emergent invasive airway access is indicated, a surgical technique such as scalpel-bougie-tube, rather than an aerosolizing generating procedure, such as transtracheal jet ventilation, is recommended.23 Additional recommendations for pediatric patients include administering anxiolytic medications, intravenous anesthetic inductions, tracheal intubation using cuffed tracheal tubes, use of inline suction catheters, and modifying workflow to recover patients from anesthesia in the operating room.19



Capacity Increase


The exponential growth in COVID-19 positive cases across the world followed by the associated increase in hospital attendances and admissions affected all levels of healthcare from community services, general practices, chronic and acute hospital services, i.e., emergency departments, diagnostic, medical, and surgical services all the way to intensive care.


Breaches of critical care capacity required surge capacity to be developed in nearly all acute hospitals. Areas that could function as escalation critical care areas were identified. Many factors had to be considered including medical gas supplies, ventilation, equipment, and staffing. Expanding the footprint of intensive care outside traditional intensive care units required staff to step up where the services of intensive care clinicians were overstretched. Operating theaters provided additional isolation capacity especially if negative pressure capability were present. These as well as postanesthesia care units were adjusted, equipped, and staffed to function as escalation intensive care spaces. Staff, from within the perioperative environment, were suitably skilled to be redeployed to temporarily increase capacity. The skills of anesthetists in airway management, mechanical ventilation, and sedation as well as training that most likely included rotations through critical care were natural fit to meet the demand. Resources and training for managing COVID-19 patients in these areas were forthcoming.31,32 Guidance on how anesthesia machines could be utilized as back-up ventilators, when there were insufficient ICU ventilators, was provided by manufacturers (ASAHQ-pdf).


Oxygen supply and demand capability should be carefully considered. The maximum flow per minute via central pipeline supply during periods of peak demand as well as volume capacity of liquid O2 supply or oxygen cylinder manifolds determined the number of patients that could be cared for as well as what type of ventilation could be offered. This was especially relevant where high-flow nasal cannula oxygen was provided to multiple patients.

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Jun 23, 2022 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on 15 COVID-19 and Anesthesia
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