Quantitative evaluation of aerosol generation from upper airway suctioning assessed during tracheal intubation and extubation sequences in anaesthetized patients.

BACKGROUND: Open respiratory suctioning is defined as an aerosol generating procedure (AGP). Laryngopharyngeal suctioning, used to clear secretions during anaesthesia, is widely managed as an AGP. However, it is uncertain whether upper airway suctioning should be designated as an AGP due to the lack of both aerosol and epidemiological evidence. AIM: To assess the relative risk of aerosol generation by upper airway suctioning during tracheal intubation and extubation in anaesthetized patients. METHODS: This prospective environmental monitoring study was undertaken in an ultraclean operating theatre setting to assay aerosol concentrations during intubation and extubation sequences, including upper airway suctioning, for patients undergoing surgery (N=19). An optical particle sizer (particle size 0.3-10 µm) sampled aerosol 20 cm above the patient's mouth. Baseline recordings (background, tidal breathing and volitional coughs) were followed by intravenous induction of anaesthesia with neuromuscular blockade. Four periods of laryngopharyngeal suctioning were performed with a Yankauer sucker: pre-laryngoscopy, post-intubation, pre-extubation and post-extubation. FINDINGS: Aerosol was reliably detected {median 65 [interquartile range (IQR) 39-259] particles/L} above background [median 4.8 (IQR 1-7) particles/L, P<0.0001] when sampling in close proximity to the patient's mouth during tidal breathing. Upper airway suctioning was associated with a much lower average aerosol concentration than breathing [median 6.0 (IQR 0-12) particles/L, P=0.0007], and was indistinguishable from background (P>0.99). Peak aerosol concentrations recorded during suctioning [median 45 (IQR 30-75) particles/L] were much lower than during volitional coughs [median 1520 (IQR 600-4363) particles/L, P<0.0001] and tidal breathing [median 540 (IQR 300-1826) particles/L, P<0.0001]. CONCLUSION: Upper airway suctioning during airway management was not associated with a higher aerosol concentration compared with background, and was associated with a much lower aerosol concentration compared with breathing and coughing. Upper airway suctioning should not be designated as a high-risk AGP.

Difficult Airway Management in Adult Coronavirus Disease 2019 Patients: Statement by the Society of Airway Management.

The coronavirus disease 2019 (COVID-19) disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), often results in severe hypoxemia requiring airway management. Because SARS-CoV-2 virus is spread via respiratory droplets, bag-mask ventilation, intubation, and extubation may place health care workers (HCW) at risk. While existing recommendations address airway management in patients with COVID-19, no guidance exists specifically for difficult airway management. Some strategies normally recommended for difficult airway management may not be ideal in the setting of COVID-19 infection. To address this issue, the Society for Airway Management (SAM) created a task force to review existing literature and current practice guidelines for difficult airway management by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. The SAM task force created recommendations for the management of known or suspected difficult airway in the setting of known or suspected COVID-19 infection. The goal of the task force was to optimize successful airway management while minimizing exposure risk. Each member conducted a literature review on specific clinical practice section utilizing standard search engines (PubMed, Ovid, Google Scholar). Existing recommendations and evidence for difficult airway management in the COVID-19 context were developed. Each specific recommendation was discussed among task force members and modified until unanimously approved by all task force members. Elements of Appraisal of Guidelines Research and Evaluation (AGREE) Reporting Checklist for dissemination of clinical practice guidelines were utilized to develop this statement. Airway management in the COVID-19 patient increases HCW exposure risk. Difficult airway management often takes longer and may involve multiple procedures with aerosolization potential, and strict adherence to personal protective equipment (PPE) protocols is mandatory to reduce risk to providers. When a patient's airway risk assessment suggests that awake tracheal intubation is an appropriate choice of technique, and procedures that may cause increased aerosolization of secretions should be avoided. Optimal preoxygenation before induction with a tight seal facemask may be performed to reduce the risk of hypoxemia. Unless the patient is experiencing oxygen desaturation, positive pressure bag-mask ventilation after induction may be avoided to reduce aerosolization. For optimal intubating conditions, patients should be anesthetized with full muscle relaxation. Videolaryngoscopy is recommended as a first-line strategy for airway management. If emergent invasive airway access is indicated, then we recommend a surgical technique such as scalpel-bougie-tube, rather than an aerosolizing generating procedure, such as transtracheal jet ventilation. This statement represents recommendations by the SAM task force for the difficult airway management of adults with COVID-19 with the goal to optimize successful airway management while minimizing the risk of clinician exposure.

A quantitative evaluation of aerosol generation during supraglottic airway insertion and removal.

Many guidelines consider supraglottic airway use to be an aerosol-generating procedure. This status requires increased levels of personal protective equipment, fallow time between cases and results in reduced operating theatre efficiency. Aerosol generation has never been quantitated during supraglottic airway use. To address this evidence gap, we conducted real-time aerosol monitoring (0.3-10-µm diameter) in ultraclean operating theatres during supraglottic airway insertion and removal. This showed very low background particle concentrations (median (IQR [range]) 1.6 (0-3.1 [0-4.0]) particles.l-1 ) against which the patient's tidal breathing produced a higher concentration of aerosol (4.0 (1.3-11.0 [0-44]) particles.l-1 , p = 0.048). The average aerosol concentration detected during supraglottic airway insertion (1.3 (1.0-4.2 [0-6.2]) particles.l-1 , n = 11), and removal (2.1 (0-17.5 [0-26.2]) particles.l-1 , n = 12) was no different to tidal breathing (p = 0.31 and p = 0.84, respectively). Comparison of supraglottic airway insertion and removal with a volitional cough (104 (66-169 [33-326]), n = 27), demonstrated that supraglottic airway insertion/removal sequences produced <4% of the aerosol compared with a single cough (p < 0.001). A transient aerosol increase was recorded during one complicated supraglottic airway insertion (which initially failed to provide a patent airway). Detailed analysis of this event showed an atypical particle size distribution and we subsequently identified multiple sources of non-respiratory aerosols that may be produced during airway management and can be considered as artefacts. These findings demonstrate supraglottic airway insertion/removal generates no more bio-aerosol than breathing and far less than a cough. This should inform the design of infection prevention strategies for anaesthetists and operating theatre staff caring for patients managed with supraglottic airways.

Comprehensive assessment of respiratory function, a step towards early weaning from the ventilator.

Methods for assessing diaphragmatic function can be useful in determining the functional status of the respiratory system and can contribute to determining an individual's prognosis, depending on their pathology. They can also be a useful tool for making objective decisions regarding mechanical ventilation weaning and extubation. Esophageal and transdiaphragmatic pressure measurement, diaphragm ultrasound, diaphragmatic excursion, surface electromyography (sEMG) and some serum biomarkers are of increasing interest and use in clinical and intensive care settings to offer a more objective process for withdrawing mechanical ventilation; especially in the situation that we are experiencing with the increased demand for mechanical ventilation to treat patients with Covid-19-associated viral pneumonia. In this literature review, we updated the clinical and physiological indicators with more evidence to improve ventilator withdrawal techniques. We concluded that, to ensure successful extubation in a way that is useful, cost-effective, practical for health personnel and non-invasive for the patient, further studies of novel techniques such as surface electromyography should be implemented.

Compassionate Removal of Heated High-Flow Nasal Cannula for End of Life: Case Series and Protocol Development.

Patients often receive burdensome care at the end of life in the form of interventions that may need to be removed. Heated high-flow oxygen delivered through a nasal cannula (HHFNC) is one such intervention that can be delivered in the hospital yet is rarely available outside of this setting. During the COVID-19 (coronavirus disease 2019) pandemic, health care systems continue to face the possibility of rationing critical life-sustaining equipment that may include HHFNC. We present a clinical protocol designed for weaning HHFNC to allow a natural death and ensuring adequate symptom management throughout the process. This was a retrospective chart review of 8 patients seen by an inpatient palliative care service of an academic tertiary referral hospital who underwent terminal weaning of HHFNC using a structured protocol to manage dyspnea. Eight patients with diverse medical diagnoses, including COVID-19 pneumonia, underwent terminal weaning of HHFNC according to the clinical protocol with 4 down-titrations of approximately 25% for both fraction of inspired oxygen and liter flow with preemptive boluses of opioid and benzodiazepine. Clinical documentation supported good symptom control throughout the weaning process. This case series provides preliminary evidence that the clinical protocol proposed has the ability to ensure comfort through terminal weaning of HHFNC.

Clinical outcomes of high-flow nasal cannula in COVID-19 associated postextubation respiratory failure. A single-centre case series.

INTRODUCTION: A high-flow nasal cannula (HFNC) is an alternative device for oxygena-tion, which improves gas exchange and reduces the work of breathing. Postextubation respiratory failure causes increased morbidity and mortality. HFNC has been widely employed during the COVID-19 pandemic. The purpose of this paper is to report a single-centre experience on the effectiveness and safety of HFNC in weaning COVID-19 patients. MATERIAL AND METHODS: Nine patients showed severe acute respiratory failure and interstitial pneumonia due to SARS-CoV-2. After mechanical ventilation (5 Helmet CPAP, 4 invasive mechanical ventilation), they were de-escalated to HFNC. Settings were: 34-37°C, flow from 50 to 60 L min-1. FiO2 was set to achieve appropriate SpO2. RESULTS: Nine patients (4 females; age 63 ± 13.27 years; BMI 27.2 ± 4.27) showed a baseline PaO2/FiO2 of 109 ± 45 mm Hg. After a long course of ventilation all patients improved (PaO2/FiO2 336 ± 72 mm Hg). Immediately after initiation of HFNC (2 hours), PaO2/FiO2 was 254 ± 69.3 mm Hg. Mean ROX index at two hours was 11.17 (range: 7.38-14.4). It was consistent with low risk of HFNC failure. No difference was observed on lactate. After 48 hours of HFNC oxygen therapy (day 3), mean PaO2/FiO2 increased to 396 ± 83.5 mm Hg. All patients recovered from respiratory failure after 7 ± 4.1 days. CONCLUSIONS: HFNC might be helpful in weaning COVID-19 respiratory failure. Effectiveness and comfort should be assessed between 2 and 48 hours. Clinical outcomes, oxygenation, and ROX index should be considered, to rule out the need for intubation. Further evidence is required for firm conclusions.

Comparison of Percentage Prolonged Times to Tracheal Extubation Between a Japanese Teaching Hospital and One in the United States, Without and With a Phase I Postanesthesia Care Unit.

BACKGROUND: Prolonged times to tracheal extubation are those from end of surgery (dressing on the patient) to extubation 15 minutes or longer. They are so long that others in the operating room (OR) generally have exhausted whatever activities can be done. They cause delays in the starts of surgeons' to-follow cases and are associated with longer duration workdays. Anesthesiologists rate them as being inferior quality. We compare prolonged times to extubation between a teaching hospital in the United States with a phase I postanesthesia care unit (PACU) and a teaching hospital in Japan without a PACU. Our report is especially important during the coronavirus disease 2019 (COVID-19) pandemic. Anesthesiologists with some patients undergoing general anesthetics and having initial PACU recovery in the ORs where they had surgery can learn from the Japanese anesthesiologists with all patients recovering in ORs. METHODS: The historical cohort study included all patients undergoing gynecological surgery at a US hospital (N = 785) or Japanese hospital (N = 699), with the time from OR entrance to end of surgery of at least 4 hours. RESULTS: The mean times from end of surgery to OR exit were slightly longer at the US hospital than at the Japanese hospital (mean difference 1.9 minutes, P < .0001). The mean from end of surgery to discharge to surgical ward at the US hospital also was longer (P < .0001), mean difference 2.2 hours. The sample standard deviations of times from end of surgery until tracheal extubation was 40 minutes for the US hospital versus 4 minutes at the Japanese hospital (P < .0001). Prolonged times to tracheal extubation were 39% of cases at the US hospital versus 6% at the Japanese hospital; relative risk 6.40, 99% confidence interval (CI), 4.28-9.56. Neither patient demographics, case characteristics, surgeon, anesthesiologist, nor anesthesia provider significantly revised the risk ratio. There were 39% of times to extubation that were prolonged among the patients receiving neither remifentanil nor desflurane (all such patients at the US hospital) versus 6% among the patients receiving both remifentanil and desflurane (all at the Japanese hospital). The relative risk 7.12 (99% CI, 4.59-11.05) was similar to that for the hospital groups. CONCLUSIONS: Differences in anesthetic practice can facilitate major differences in patient recovery soon after anesthesia, useful when the patient will recover initially in the OR or if the phase I PACU is expected to be unable to admit the patient.

Intraoperative Diagnosis of Coronavirus Disease 2019 in an Asymptomatic Patient: A Case Report.

Patients with coronavirus disease 2019 (COVID-19) with variable clinical presentations are encountered in the perioperative setting. While some have already been diagnosed and are symptomatic, others have undiagnosed, asymptomatic COVID-19. The latter group poses the greatest risk of transmission. Given limited capacities in most health care systems, diagnostic testing is mainly performed in symptomatic patients or those with relevant exposure. We report an intraoperative diagnosis of COVID-19 in an asymptomatic patient, prompted by clinical signs. To control a pandemic such as COVID-19, a high index of suspicion is pivotal when caring for asymptomatic patients in the perioperative setting.

Reducing Aerosol Generation During Ventilator Weaning in a Coronavirus Disease 2019 Patient Using a Supraglottic Airway: A Case Report.

We report weaning from mechanical ventilation with no coughing in a patient with coronavirus disease 2019 (COVID-19). Substituting the endotracheal tube for a supraglottic airway (SGA), which is less stimulating to the trachea, can reduce coughing with weaning from mechanical ventilation and extubation. Personal protective equipment is in short supply worldwide. Reducing spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is beneficial in terms of occupational health of health care workers.

Airway Management in the Operating Room and Interventional Suites in Known or Suspected COVID-19 Adult Patients: A Practical Review.

Current evidence suggests that coronavirus disease 2019 (COVID-19) spread occurs via respiratory droplets (particles >5 µm) and possibly through aerosol. The rate of transmission remains high during airway management. This was evident during the 2003 severe acute respiratory syndrome epidemic where those who were involved in tracheal intubation had a higher risk of infection than those who were not involved (odds ratio 6.6). We describe specific airway management principles for patients with known or suspected COVID-19 disease for an array of critical care and procedural settings. We conducted a thorough search of the available literature of airway management of COVID-19 across a variety of international settings. In addition, we have analyzed various medical professional body recommendations for common procedural practices such as interventional cardiology, gastroenterology, and pulmonology. A systematic process that aims to protect the operators involved via appropriate personal protective equipment, avoidance of unnecessary patient contact and minimalization of periprocedural aerosol generation are key components to successful airway management. For operating room cases requiring general anesthesia or complex interventional procedures, tracheal intubation should be the preferred option. For interventional procedures, when tracheal intubation is not indicated, cautious conscious sedation appears to be a reasonable approach. Awake intubation should be avoided unless it is absolutely necessary. Extubation is a high-risk procedure for aerosol and droplet spread and needs thorough planning and preparation. As updates and modifications in the management of COVID-19 are still evolving, local guidelines, appraised at regular intervals, are vital in optimizing clinical management.

Comparison of the Effectiveness of Different Barrier Enclosure Techniques in Protection of Healthcare Workers During Tracheal Intubation and Extubation.

The coronavirus disease 2019 (COVID-19; SARS-CoV-2) pandemic has created serious challenges to anesthesiologists. As hospitalized patients' respiratory function deteriorates, many will require endotracheal intubation. Airway management of infected patients risks aerosolization of viral-loaded droplets that pose serious hazards to the anesthesiologist and all health care personnel present. The addition of an enclosure barrier during airway management minimizes the hazard by entrapping the droplets and possibly the aerosols within an enclosed space adding additional protection for health care workers. The aim of this study was to compare the effectiveness of different barrier enclosure techniques during tracheal intubation and extubation.

Failure of early extubation among cases of coronavirus disease-19 respiratory failure: Case report and clinical experience.

RATIONALE: Extubation strategy for mechanically ventilated patients with Coronavirus Disease 19 is different from that for patients with other viral pneumonia. We reported 2 cases of Coronavirus Disease 19 receiving tracheal intubation twice during the hospitalization. PATIENT CONCERNS: Two elderly patients with onset of fever and upper respiratory tract infection were confirmed as Coronavirus Disease 19, 1 of whom had chronic obstructive pulmonary disease previously. With active antiviral and noninvasive respiratory supportive therapy, there was no improvement, thus mechanical ventilation (MV) was adopted. Combining with symptomatic and supportive treatment, their oxygenation recovered and then extubation was carried out. However, 96 hours later, they underwent endotracheal intubation again due to their Coronavirus Disease 19 progression. DIAGNOSIS: Critically ill Coronavirus Disease 19 requiring tracheal intubation owing to respiratory failure with lung.javascript. INTERVENTIONS: Initial Strategy for respiratory failure included endotracheal intubation, MV, antiviral treatment and cortisol in both cases. When extubation criteria were satisfied, early discontinuation of MV was conducted, then rehabilitation exercise and nutritional support followed. However, 96 hours later, the disease progressed leading to respiratory failure again, thus reintubation was performed. Later, veno-venous extracorporeal membrane oxygenation was performed owing to aggravation of respiratory failure, assisted by prone position treatment and sputum drainage, then status became stable and stepped into recovery stage. OUTCOMES: Both patients underwent reintubation, and their MV time and Intensive care unit residence time were prolonged. Through prone position treatment, sputum drainage and awake extracorporeal membrane oxygenation strategy, patient has been transferred to rehabilitation unit in Case 1, and patient in Case 2 has been in recovery stage as well with stable pulmonary status and was expected to receive evaluation in recent future. LESSONS: Course of Coronavirus Disease 19 is relatively longer, and failure rate of simple early extubation seemes higher. To reduce the likelihood of reintubation and iatrogenic injury, individualized assessment is recommended.

Safe extubation during the COVID-19 pandemic.

Extubation of patients with Coronavirus Disease 2019 (COVID-19) is a high risk procedure for both patients and staff. Shortages in personal protective equipment (PPE) and the high volume of contact staff have with COVID-19 patients has generated an interest in ways to reduce exposure that might be feasible especially during pandemic times and in resource limited healthcare settings. The development of portable barrier hood devices (or intubation/extubation boxes) is an area of interest for many clinicians due to the theoretical reduction in aerosolization of SARS-CoV-2, the causative virus for COVID-19. We present a review of the current literature along with recommendations concerning safe extubation during the COVID-19 pandemic. In addition, a focused summary on the use of portable barrier hood devices, during the recent surge of COVID-19 is highlighted.