Efficacy of Nasal Cannula Oxygen as a Preoxygenation Adjunct in Emergency Airway Management

Factors Associated With Desaturation in Prehospital Rapid Sequence Intubation in a Helicopter Emergency Medical Service

OBJECTIVE

Desaturation during prehospital rapid sequence intubation (RSI) is common and is associated with patient morbidity. Past studies have identified oxygen saturations at induction, the grade of laryngoscopy, and multiple attempts to intubate as being associated with desaturation. This study aimed to investigate whether there are other factors, identifiable before RSI, associated with desaturation.

METHODS

This was a study of a physician-paramedic critical care team operating as Aeromedical Operations, NSW Ambulance. Prehospital RSIs (using paralysis) were studied retrospectively via patient case notes, monitor data, and an airway database. The review occurred between April 1, 2016, and December 31, 2018. Desaturation was defined as monitor recordings of saturations ≤ 92%. Logistic regression was performed for factors likely to be associated with desaturation.

RESULTS

Desaturation occurred in 67 of 350 (19.1%) RSIs. Factors significantly associated with desaturation included male sex, a chest injury, increased weight, and lower saturations pre-RSI.

CONCLUSION

Increased weight, chest injuries, and lower oxygen saturations are associated with desaturation at RSI. The variable male sex may be a surrogate for other as-yet unidentified factors.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part I

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Preoxygenation: from hardcore physiology to the operating room

If we define the human body by the mass of the elements that compose it, we could say that we are oxygen and other elements. Oxygen, in addition to being fundamental in our composition, is an element that we constantly need to support cellular respiration and, therefore, life. Interestingly, despite its importance, humans have not developed mechanisms that allow us to store it and, therefore, we are unable to sustain life if we are deprived of ventilation, even for brief periods. Accordingly, the ability to induce the cessation of ventilation in a patient must be accompanied by different technical and non-technical skills that allow the patient's safety to be maintained in this highly vulnerable state. Through the use of basic mathematical tools and comparative physiology, we hereby propose to review the physiological foundations of preoxygenation to understand the reasons behind the clinical recommendations in this field.

Medium-Flow Oxygenation Through Facial Mask and Nasal Cannula in a Limited Resource Setting

Introduction: In centers with limited resources, a high flow nasal cannula is not available, thus we assess if preoxygenation with 15L flow of O2 available from anesthesia machines can prolong the safety period of induction of anesthesia before intubation and provide more time for securing the airway. Moreover, we compared the preoxygenation with standard 6L vs. 15L O2 through a facemask or a nasal cannula. Material and methods: Patients were allocated into four groups. Group I patients were preoxygenated with a nasal cannula on 6L of oxygen, patients in group II were preoxygenated with a nasal cannula on 15L of oxygen, patients in group III were preoxygenated with a facemask on 6L of oxygen, and patients in group IV were preoxygenated with a facemask on 15L of oxygen. The primary endpoint was time to desaturation and intubation. The secondary endpoints were PaO2, PaCO2, Sat% and ETCO2. Results: The groups with 15L preoxygenation had a statistically significant prolonged time to desaturation and intubation. Patients allocated to group II have a statistically significant greater PaO2 and lesser ETCO2 compered with group I. However, between patients in group III and IV there is a difference only in PaCO2, and although this effect is significant, both groups have values within the normal range. Conclusion: In centers with limited resources, preoxygenation with the maximum available oxygen flow from anesthesia machines (15L/min) are useful. This prolongs the safety period for securing the airway. We suggest the use of the maximum available amount of oxygen flow from anesthesia machines in clinical settings.

Comparison of High-flow Nasal Cannula (HFNC) and Conventional Oxygen Therapy in Obese Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-analysis

BACKGROUND/AIM

High-flow nasal cannula (HFNC), a new method for postoperative oxygenation, has increasingly received attention during postoperative care. However, its importance for obese patients undergoing cardiac surgery remains controversial. This systematic review and meta-analysis compared and evaluated HFNC and conventional oxygen therapy (COT) in this patient group.

MATERIALS AND METHODS

Literature was retrieved by searching eight public databases. Randomized controlled trials (RCTs) were selected. RevMan 5.3 was used to analyze the results and any potential bias. The primary outcome included atelectasis score at 24 h postoperatively. The secondary outcomes included PaO2/FiO2 (ratio), dyspnea score at 24 h postoperatively, intensive care unit (ICU) length of stay, and reintubation.

RESULTS

The search strategy yielded 382 studies after duplicates were removed. Finally, 3 RCTs with a total of 526 patients were included in the present study. Compared with COT, there was no significant difference in atelectasis score, dyspnea score, reintubation, and ICU length of stay.

CONCLUSION

For obese patients undergoing cardiac surgery, postoperative use of HFNC can maintain patient's oxygenation. Additional clinical studies are needed to investigate the role of HFNC in this patient group.

Airway Management in the Critically Ill Patient

Purpose of Review

This paper will evaluate the recent literature and best practices in airway management in critically ill patients.

Recent Findings

Cardiac arrest remains a common complication of intubation in these high-risk patients. Patients with desaturation or peri-intubation hypotension are at high risk of cardiac arrest, and each of these complications have been reported in up to half of all intubations in critically ill patient populations.

Summary

There have been significant advances in preoxygenation and devices available for performing laryngoscopy and rescue oxygenation. However, the risk of cardiovascular collapse remains concerningly high with few studies to guide therapeutic maneuvers to reduce this risk.

Evaluation and Management of the Physiologically Difficult Airway: Consensus Recommendations From Society for Airway Management

Multiple international airway societies have created guidelines for the management of the difficult airway. In critically ill patients, there are physiologic derangements beyond inadequate airway protection or hypoxemia. These risk factors contribute to the "physiologically difficult airway" and are associated with complications including cardiac arrest and death. Importantly, they are largely absent from international guidelines. Thus, we created management recommendations for the physiologically difficult airway to provide practical guidance for intubation in the critically ill. Through multiple rounds of in-person and telephone conferences, a multidisciplinary working group of 12 airway specialists (Society for Airway Management's Special Projects Committee) over a time period of 3 years (2016-2019) reviewed airway physiology topics in a modified Delphi fashion. Consensus agreement with the following recommendations among working group members was generally high with 80% of statements showing agreement within a 10% range on a sliding scale from 0% to 100%. We limited the scope of this analysis to reflect the resources and systems of care available to out-of-operating room adult airway providers. These recommendations reflect the practical application of physiologic principles to airway management available during the analysis time period.

Apnoeic oxygenation was associated with decreased desaturation rates during rapid sequence intubation in multiple Australian and New Zealand emergency departments

Apnoeic oxygenation (ApOx) has been demonstrated to reduce the incidence of desaturation, although evidence of benefit has been conflicting depending on the technique used. The aim of this study was to compare the incidence of desaturation between patients who received ApOx via conventional nasal cannula (NC) and those who did not, using a large, multicentre airway registry.

METHODS

This study is an analysis of 24 months of prospectively collected data in the Australia and New Zealand Emergency Department Airway Registry (June 2013-June 2015). The registry includes information on all intubated adults from 43 emergency departments. Patients intubated during cardiac arrest (n=393), those who received active ventilation prior to the first intubation attempt (n=486), and where the use of ApOx was not recorded either way (n=312) were excluded. The proportion of patients who desaturated (Sa0₂ <93) in the group that received ApOx and those that did not were compared. To evaluate the association of ApOx with patient desaturation, a logistic regression model based on factors expected to influence desaturation was performed.

RESULTS

Of 2519 patients analysed, 1669 (66.3%) received ApOx via NC while 850 (33.7%) did not. Desaturation in the cohort receiving ApOx was 10.4% compared with standard care (no ApOx) 13.7%. ApOx had a protective effect for desaturation (OR 0.71 95% CI 0.53 to 0.95). Single intubation attempt was associated with reduced risk of desaturation of (OR 0.10, 95% CI 0.06 to 0.17); this was increased on second attempt (OR 0.37, 95% CI 0.21 to 0.68). Desaturation was also associated with the physician recording that they had anticipated a difficult airway (OR 1.83, 95% CI 1.34 to 2.48).

CONCLUSION

This large multicentre registry study provides evidence that ApOx delivered through a conventional NC is associated with a lower incidence of desaturation in patients undergoing rapid sequence intubation.

TRIAL REGISTRATION NUMBER

ACTRN12613001052729.

Evolving oxygenation management reasoning in COVID-19

The initial phase of the SARS-CoV-2 pandemic in the United States saw rapidly-rising patient volumes along with shortages in personnel, equipment, and intensive care unit (ICU) beds across many New York City hospitals. As our hospital wards quickly filled with unstable, hypoxemic patients, our hospitalist group was forced to fundamentally rethink the way we triaged and managed cases of hypoxemic respiratory failure. Here, we describe the oxygenation protocol we developed and implemented in response to changing norms for acuity on inpatient wards. By reflecting on lessons learned, we re-evaluate the applicability of these oxygenation strategies in the evolving pandemic. We hope to impart to other providers the insights we gained with the challenges of management reasoning in COVID-19.

Emergency physician use of end-tidal oxygen monitoring for rapidsequence intubation

BACKGROUND

End-tidal oxygen (ETO2) monitoring is used by anesthesiologists to quantify the efficacy of preoxygenation before intubation but is generally not used in emergency departments (EDs). We have previously published our findings describing preoxygenation practices in the ED during blinded use of ETO2. The purpose of this investigation is to determine whether the unblinded use of ETO2 monitoring led to improvements in preoxygenation during rapid sequence intubation in the ED and also the oxygen device or technique changes that were used to achieve higher ETO2 levels.

METHODS

We conducted an interventional study at 2 academic EDs in Sydney, Australia and New York City, New York using ETO2 monitoring to investigate the preoxygenation process and effectiveness. We used data collected during a previous descriptive study for the control group, in which care teams in the same 2 EDs were blinded to the ETO2 value. In the study group, clinicians could utilize ETO2 to improve preoxygenation. Following an education process, clinicians were able to choose the method of preoxygenation and the techniques required to attempt to achieve an ETO2 level >85%. The primary outcome was the difference in ETO2 levels at the time of induction between the control and study group and the secondary outcome included the methods that were attempted to improve preoxygenation.

RESULTS

A convenience sample of 100 patients was enrolled in each group. The median ETO2 level achieved at the time of induction was 80% (interquartile range 61 to 86, overall range 73) in the control group and 90% in the study group (interquartile range 83 to 92, overall range 41); the median difference was 12 (95% confidence interval: 8, 16, P = < 0.001). The majority of oxygen device changes were from non-rebreather mask to bag-valve-mask (BVM) (15%, n = 15) and changes in technique from improvements in mask seal (54%, n = 34). The final device used in the study group was BVM in 87% of cases.

CONCLUSIONS

In 2 clinical studies of ETO2 in academic EDs, we have demonstrated that the use of ETO2 is feasible and associated with specific and potentially improved approaches to preoxygenation. A clinical trial is needed to further study the impact of ETO2 on the preoxygenation process and the rate of hypoxemia.

Intubation practices for children in emergency departments and intensive care units across Australia and New Zealand: A survey of medical staff

OBJECTIVE

Intubation of children in the emergency setting is a high-risk, low incidence event. Standardisation of clinical practice has been hampered by a lack of high-quality evidence to support one technique over another. The aim of the present study is to determine clinician preference in intubation practice of children in EDs and ICUs in Australia and New Zealand to provide baseline information to allow future targeted research focused on improving the safety and efficacy of paediatric emergency airway management.

METHODS

The present study was a voluntary questionnaire undertaken by medical staff at registrar level or above in EDs and ICUs associated with the Paediatric Research in Emergency Departments International Collaborative (PREDICT) and Australia and New Zealand Intensive Care Society Paediatric Study Group (ANZICS PSG) research networks. Respondents reported on their individual intubation practices, with a focus on pre-oxygenation and apnoeic oxygenation techniques, and the use of video laryngoscopy.

RESULTS

A total of 502 clinicians were invited to complete the survey between May and October 2018 with 336 (66.9%) responded. There was marked variation in practice between ED clinicians and ICU clinicians in the techniques used for pre-oxygenation, the frequency of use of apnoeic oxygenation and the reported use of video laryngoscopy.

CONCLUSIONS

Within Australia and New Zealand there is considerable variation in paediatric emergency airway clinical practice, in particular with respect to pre-oxygenation, apnoeic oxygenation and use of video laryngoscopy. Definitive clinical trials are required to best inform clinical practice in this area.

Time to Loss of Preoxygenation in Emergency Department Patients

BACKGROUND

In patients requiring emergency rapid sequence intubation (RSI), 100% oxygen is often delivered for preoxygenation to replace alveolar nitrogen with oxygen. Sometimes, however, preoxygenation devices are prematurely removed from the patient prior to the onset of apnea, which can lead to rapid loss of preoxygenation.

OBJECTIVE

We sought to determine the elapsed time, on average, between removing the oxygen source and the loss of preoxygenation among non-critically ill patients in the emergency department (ED).

METHODS

We conducted a prospective, crossover study of non-critically ill patients in the ED. Each patient received two identical preoxygenation trials for 4 min using a non-rebreather mask with oxygen flow at flush rate and a nasal cannula with oxygen flow at 10 L/min. After each preoxygenation trial, patients underwent two trials in random order while continuing spontaneous breathing: 1) removal of both oxygen sources and 2) removal of non-rebreather mask with nasal cannula left in place. We defined loss of preoxygenation as an end-tidal oxygen (exhaled oxygen percentage; EtO₂) value < 70%. We measured EtO₂ breath by breath until loss of preoxygenation occurred.

RESULTS

We enrolled 42 patients, median age was 43 years (interquartile range [IQR] 30 to 54 years) and 72% were male. Median time to loss of preoxygenation was 20 s (IQR 17-25 s, 4.5 breaths) when all oxygen devices were removed, and 39 s (IQR 21-56 s, 8 breaths) when the nasal cannula was left in place.

CONCLUSIONS

In this population of non-critically ill ED patients, most had loss of preoxygenation after 5 breaths if all oxygen devices were removed, and after 8 breaths if a nasal cannula was left in place. These data suggest that during ED RSI, preoxygenation devices should be left in place until the patient is completely apneic.

High-flow nasal oxygenation for anesthetic management

High-flow nasal oxygenation (HFNO) is a promising new technique for anesthesiologists. The use of HFNO during the induction of anesthesia and during upper airway surgeries has been initiated, and its applications have been rapidly growing ever since. The advantages of this technique include its easy set-up, high tolerability, and its abilities to produce positive airway pressure and a high fraction of inspired oxygen and to influence the clearance of carbon dioxide to some extent. HFNO, via a nasal cannula, can provide oxygen both to patients who can breathe spontaneously and to those who are apneic; further, this technique does not interfere with bag-mask ventilation, attempts at laryngoscopy for tracheal intubation, and surgical procedures conducted in the airway. In this review, we describe the techniques associated with HFNO and the advantages and disadvantages of HFNO based on the current state of knowledge.

Humidified versus nonhumidified low-flow oxygen therapy in children with Pierre-Robin syndrome: Study protocol for a randomised controlled trial

AIMS AND OBJECTIVES

To evaluate the necessity of oxygen humidification for low-flow oxygen therapy in children with Pierre-Robin syndrome.

BACKGROUND

Whether to carry out humidification or not in the low-flow oxygen delivery remains unclear, and currently, there is no published study on this issue in the population of children. Therefore, it is necessary to conduct more studies to elucidate this issue.

DESIGN

A randomised controlled trial.

METHODS

We attempt to report this randomised controlled trial to comply with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT). 188 children with Pierre-Robin syndrome will be expected to inclusion. The participants will be randomly divided into the humidified group (n = 94) and nonhumidified group (n = 94) at a ratio of 1:1. For humidified group, the oxygen will be routinely humidified with disposable bottle containing sterile water, whereas for nonhumidified group, the oxygen will not be humidified. Average arterial oxygen partial pressure (PaO₂ ) and carbon dioxide partial pressure (PaCO₂ ), incidence of ventilator-associated pneumonia (VAP), nasal cavity dryness, nasal mucosal bleeding and bacterial contamination of the humidified bottle, the cost of nasal oxygen therapy and duration of ICU stay are collected and analysed.

RESULTS

The study is planned to start in May 2019, and the results will be expected in July 2020.

CONCLUSIONS

This study is expected to provide a credible evidence on the necessity of routine oxygen humidification in low-flow oxygen delivery.

RELEVANCE TO CLINICAL PRACTICE

Understanding the role of oxygen humidification and no humidification for low-flow oxygen therapy in the population of children is beneficial to the nursing care of healthcare providers in clinical setting.

Addition of Nasal Cannula Can Either Impair or Enhance Preoxygenation With a Bag Valve Mask: A Randomized Crossover Design Study Comparing Oxygen Flow Rates

BACKGROUND

A critical safety component of emergency anesthesia is the avoidance of hypoxemia during the apneic phase of a rapid sequence intubation. Preoxygenation with a bag valve mask (BVM) or anesthetic circuit may be improved with supplemental oxygen by nasal cannula (NC) if there is a mask leak. In addition, NC is recommended for apneic oxygenation after induction and may be placed before preoxygenation. However, the optimum NC flow rate for preoxygenation or whether the presence of NC alone creates a mask leak remains unclear.

METHODS

We performed a randomized crossover study on healthy volunteers comparing BVM alone and BVM with NC flow rates of 0 (NC-0), 5 (NC-5), 10 (NC-10), and 15 (NC-15) liters per minute (lpm). Our primary outcome was end-tidal oxygen (ETO2) after 3-minute preoxygenation.

RESULTS

There was no difference in ETO2 between NC-15, NC-10, or BVM-only at 3 minutes. NC-0 and NC-5 recorded significantly lower ETO2 at all times compared with NC-15, NC-10, or BVM-only (least difference NC-5, -7% [95% confidence interval {CI}, -4% to -10%), NC-0, 16% [95% CI, 13%-19%]). There was a difference in ETO2 between NC-15 and BVM-only at 1 minute (7%; 95% CI, 5%-9%), but not at 2 or 3 minutes. There was no difference in ETO2 between NC-10 and NC-15.

CONCLUSIONS

Our study found that NC at 0 and 5 lpm with a BVM is deleterious to preoxygenation and should be avoided. In addition, a lack of difference between NC-10 and BVM-only demonstrates that NC at flows of at least 10 lpm should not impair the preoxygenation process. While NC-15 may offer a benefit by reaching maximal ETO2 at 1 minute, this would need to be balanced against patient comfort.

Evaluation and application of a method for estimating nasal end-tidal O2 fraction while administering supplemental O2

This paper describes a method for estimating the oxygen enhanced end-tidal fraction of oxygen (F_etO_e), the end-tidal fraction of oxygen (F_etO₂) that is raised by administering supplemental oxygen. The paper has two purposes: the first is to evaluate the method's accuracy on the bench and in volunteers; the second purpose is to demonstrate how to apply the method to compare two techniques of oxygen administration. The method estimates F_etO_e by analyzing expired oxygen as oxygen washes out of the lung. The method for estimating F_etO_e was first validated using a bench simulation in which tracheal oxygen was measured directly. Then it was evaluated in 30 healthy volunteers and compared to the bench simulation. Bland-Altman analysis compared calculated and observed F_etO_e/F_etO₂ measurements. After the method was evaluated, it was implemented to compare the F_etO_e obtained when administering oxygen using two different techniques (pulsed and continuous flow). A total of eighteen breath washout conditions were evaluated on the bench. F_etO_e estimates and tracheal F_etO₂ had a mean difference of - 0.016 FO₂ with 95% limits of agreement from - 0.048 to 0.016 FO₂. Thirteen breath washouts per volunteer were analyzed. Extrapolated and observed F_etO₂ had a mean difference of - 0.001 FO₂ with 95% limits of agreement from - 0.006 to 0.004 FO₂. Pulsed flow oxygen (PFO) achieved the same F_etO_e values as continuous flow oxygen (CFO) using 32.1% ± 2.27% (mean ± SD) of the CFO rate. This paper has demonstrated that the method estimates F_etO₂ enhanced by administering supplemental oxygen with clinically insignificant differences. This paper has also shown that PFO can obtain F_etO₂ similar to CFO using approximately one-third of the oxygen volume. After evaluating this method, we conclude that the method provides useful estimates of nasal F_etO₂ enhanced by supplemental oxygen administration.

Face mask leak with nasal cannula during noninvasive positive pressure ventilation: A randomized crossover trial

BACKGROUND

Nasal cannula can achieve apneic oxygenation during emergency intubation. However, pre-procedure nasal cannula placement may be difficult in patients undergoing non-invasive positive pressure ventilation (NPPV) prior to intubation. Our objective was to compare mask leak during NPPV with versus without simultaneous application of nasal cannula. We hypothesized mask leak would be no worse with concomitant use of nasal cannula (non-inferiority design).

METHODS

We performed a randomized crossover non-inferiority study of healthy volunteers. We randomized subjects undergoing 60s trials of NPPV (10cmH₂O continuous positive airway pressure) to either NPPV alone (NPPV-a) or NPPV with nasal cannula at 15L/min (NPPV-nc). After a brief rest period, all subjects underwent the alternative intervention. The primary outcome was time averaged mask leak over 60s (L/min). We defined a non-inferiority margin of 5L/min.

RESULTS

We enrolled 64 subjects. Mean time-averaged mask leak was 2.2L/min for NPPV-a versus 4.0L/min for NPPV-nc for a difference of 1.7L/min (one-sided 95% CI -∞ to 3.2L/min). NPPV-a resulted in higher mean minute volume received (13.5 versus 12.2L) and higher mean respiratory rates (14.8 versus 13.5 breaths per minute).

CONCLUSION

The addition of nasal cannula during NPPV does not significantly increase mask leak. The simultaneous application of nasal cannula with NPPV may be a useful strategy to streamline airway management among patients undergoing NPPV prior to intubation.

Republication: All India Difficult Airway Association 2016 Guidelines for Tracheal Intubation in the Intensive Care Unit

Tracheal intubation (TI) is a routine procedure in the Intensive Care Unit (ICU) and is often lifesaving. In contrast to the controlled conditions in the operating room, critically ill patients with respiratory failure and shock are physiologically unstable. These factors, along with under evaluation of the airway and suboptimal response to preoxygenation, are responsible for a high incidence of life-threatening complications such as severe hypoxemia and cardiovascular collapse during TI in the ICU. The All India Difficult Airway Association (AIDAA) proposes a stepwise plan for safe management of the airway in critically ill patients. These guidelines have been developed based on available evidence; Wherever, robust evidence was lacking, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the (AIDAA) and Indian Society of Anaesthesiologists. Noninvasive positive pressure ventilation for preoxygenation provides adequate oxygen stores during TI for patients with respiratory pathology. Nasal insufflation of oxygen at 15 L/min can increase the duration of apnea before hypoxemia sets in. High flow nasal cannula oxygenation at 60-70 L/min may also increase safety during intubation of critically ill patients. Stable hemodynamics and gas exchange must be maintained during rapid sequence induction. It is necessary to implement an intubation protocol during routine airway management in the ICU. Adherence to a plan for difficult airway management incorporating the use of intubation aids and airway rescue devices and strategies is useful.

All India Difficult Airway Association 2016 guidelines for the management of unanticipated difficult tracheal intubation in adults

The All India Difficult Airway Association (AIDAA) guidelines for management of the unanticipated difficult airway in adults provide a structured, stepwise approach to manage unanticipated difficulty during tracheal intubation in adults. They have been developed based on the available evidence; wherever robust evidence was lacking, or to suit the needs and situation in India, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the AIDAA and the Indian Society of Anaesthesiologists. We recommend optimum pre-oxygenation and nasal insufflation of 15 L/min oxygen during apnoea in all patients, and calling for help if the initial attempt at intubation is unsuccessful. Transnasal humidified rapid insufflations of oxygen at 70 L/min (transnasal humidified rapid insufflation ventilatory exchange) should be used when available. We recommend no more than three attempts at tracheal intubation and two attempts at supraglottic airway device (SAD) insertion if intubation fails, provided oxygen saturation remains ≥ 95%. Intubation should be confirmed by capnography. Blind tracheal intubation through the SAD is not recommended. If SAD insertion fails, one final attempt at mask ventilation should be tried after ensuring neuromuscular blockade using the optimal technique for mask ventilation. Failure to intubate the trachea as well as an inability to ventilate the lungs by face mask and SAD constitutes 'complete ventilation failure', and emergency cricothyroidotomy should be performed. Patient counselling, documentation and standard reporting of the airway difficulty using a 'difficult airway alert form' must be done. In addition, the AIDAA provides suggestions for the contents of a difficult airway cart.

The All India Difficult Airway Association 2016 guidelines for tracheal intubation in the Intensive Care Unit

Tracheal intubation (TI) is a routine procedure in the Intensive Care Unit (ICU) and is often life-saving. In contrast to the controlled conditions in the operating room, critically ill patients with respiratory failure and shock are physiologically unstable. These factors, along with a suboptimal evaluation of the airway and limited oxygen reserves despite adequate pre-oxygenation, are responsible for a high incidence of life-threatening complications such as severe hypoxaemia and cardiovascular collapse during TI in the ICU. The All India Difficult Airway Association (AIDAA) proposes a stepwise plan for safe management of the airway in critically ill patients. These guidelines have been developed based on available evidence; wherever robust evidence was lacking, recommendations were arrived at by consensus opinion of airway experts, incorporating the responses to a questionnaire sent to members of the AIDAA and the Indian Society of Anaesthesiologists. Non-invasive positive pressure ventilation during pre-oxygenation improves oxygen stores in patients with respiratory pathology. Nasal insufflation of oxygen at 15 L/min can increase the duration of apnoea before the occurrence of hypoxaemia. High-flow nasal cannula oxygenation at 60-70 L/min may also increase safety during TI in critically ill patients. Stable haemodynamics and gas exchange must be maintained during rapid sequence induction. It is necessary to implement an intubation protocol during routine airway management in the ICU. Adherence to a plan for difficult airway management incorporating the use of intubation aids and airway rescue devices and strategies is useful.

Applications of Nasal High-Flow Oxygen Therapy in Critically ill Adult Patients

The use of nasal high-flow oxygen therapy (NHFOT) has become increasingly common in hospitals across Europe, Asia, and North America. These high utility devices provide an efficient and comfortable access points for providing supplemental oxygen to patients with variety of respiratory disorders. They are relatively easy to set up, and clinicians and patients alike give very positive feedback about their ease of use and comfort for patients in the hospital setting. However, it remains uncertain whether NHFOT improves patient survival or even reduces respiratory complications. Outcome data in adult populations are few and frequently underpowered to guide physicians for their widespread use in hospital setting. In this article, we present a review of the current technology and available studies pertinent to NHFOT.