Noninvasive ventilation improves preoxygenation before intubation of hypoxic patients

Randomized Trial of Apneic Oxygenation during Endotracheal Intubation of the Critically Ill

RATIONALE

Hypoxemia is common during endotracheal intubation of critically ill patients and may predispose to cardiac arrest and death. Administration of supplemental oxygen during laryngoscopy (apneic oxygenation) may prevent hypoxemia.

OBJECTIVES

To determine if apneic oxygenation increases the lowest arterial oxygen saturation experienced by patients undergoing endotracheal intubation in the intensive care unit.

METHODS

This was a randomized, open-label, pragmatic trial in which 150 adults undergoing endotracheal intubation in a medical intensive care unit were randomized to receive 15 L/min of 100% oxygen via high-flow nasal cannula during laryngoscopy (apneic oxygenation) or no supplemental oxygen during laryngoscopy (usual care). The primary outcome was lowest arterial oxygen saturation between induction and 2 minutes after completion of endotracheal intubation.

MEASUREMENTS AND MAIN RESULTS

Median lowest arterial oxygen saturation was 92% with apneic oxygenation versus 90% with usual care (95% confidence interval for the difference, -1.6 to 7.4%; P = 0.16). There was no difference between apneic oxygenation and usual care in incidence of oxygen saturation less than 90% (44.7 vs. 47.2%; P = 0.87), oxygen saturation less than 80% (15.8 vs. 25.0%; P = 0.22), or decrease in oxygen saturation greater than 3% (53.9 vs. 55.6%; P = 0.87). Duration of mechanical ventilation, intensive care unit length of stay, and in-hospital mortality were similar between study groups.

CONCLUSIONS

Apneic oxygenation does not seem to increase lowest arterial oxygen saturation during endotracheal intubation of critically ill patients compared with usual care. These findings do not support routine use of apneic oxygenation during endotracheal intubation of critically ill adults. Clinical trial registered with www.clinicaltrials.gov (NCT 02051816).

Acute respiratory compromise on inpatient wards in the United States: Incidence, outcomes, and factors associated with in-hospital mortality

AIM

To estimate the United States' incidence and in-hospital mortality of acute respiratory events on inpatient wards and to identify factors associated with mortality.

METHODS

This is an analysis of prospectively collected data from the Get With the Guidelines(®) - Resuscitation registry. We included adult patients with index acute respiratory events on inpatient wards from January 2005 to December 2013. A negative binomial regression model was used to estimate the 2012 United States incidence and a multivariable logistic regression model was used to examine time trends and characteristics associated with in-hospital mortality.

RESULTS

There were 13,086 index events from 320 hospitals included in the analysis. Using 2012 data, the estimated number of events in the United States was 44,551 (95%CI: 25,170-95,371). The in-hospital mortality for the entire cohort was 39.4% (95%CI: 38.5, 40.2) and rose to 82.6% (95%CI: 79.9, 85.2) for events leading to cardiac arrest. There was a decrease in in-hospital mortality over time (48.3% in 2005 to 34.5% in 2013, p<0.001). Characteristics associated with mortality included agonal breathing, hypotension and septicemia.

CONCLUSIONS

Acute respiratory events on inpatient wards in the US is common with an associated in-hospital mortality of approximately 40% that has been decreasing over the past decade. Multiple factors were associated with in-hospital mortality.

The utility of noninvasive nasal positive pressure ventilators for optimizing oxygenation during rapid sequence intubation

OBJECTIVES

The objective of the study is to investigate the feasibility of noninvasive nasal positive pressure ventilation (NINPPV) for optimizing oxygenation during the rapid sequence intubation in critically ill patients.

METHODS

A prospective, observational study was performed in an emergency department. Noninvasive nasal positive pressure ventilation was applied in the preoxygenation step and maintained until successful intubation. A pulse oximetry (Spo2) was continuously monitored throughout the procedure and recorded 5 times. The degree of interfering was surveyed with 10-point Likert scale.

RESULTS

Thirty patients were enrolled. The most of enrolled patients were diagnosed as pneumonia, acute heart failure, and traumatic brain injury. The Spo2 was increased to 100% (98%-100%) at the time of starting endotracheal intubation with NINPPV and maintained as 97% (95%-100%) until successful intubation (P< .001). Total apnea duration was 195 seconds (190-196). The degree of interfering intubation was 1 (0-1).

CONCLUSIONS

Noninvasive nasal positive pressure ventilation would be useful for optimizing oxygenation during rapid sequence intubation.

Noninvasive Ventilation for the Emergency Physician

Noninvasive ventilation (NIV) improves oxygenation and ventilation, prevents endotracheal intubation, and decreases the mortality rate in select patients with acute respiratory failure. Although NIV is used commonly for acute exacerbations of chronic obstructive pulmonary disease and acute cardiogenic pulmonary edema, there are emerging indications for its use in the emergency department. Emergency physicians must be knowledgeable regarding the indications and contraindications for NIV in emergency department patients with acute respiratory failure as well as the means of initiating it and monitoring patients who are receiving it.

Assessment of Common Preoxygenation Strategies Outside of the Operating Room Environment

OBJECTIVES

Preoxygenation prior to intubation aims to increase the duration of safe apnea by causing denitrogenation of the functional residual capacity, replacing this volume with a reservoir of oxygen. In the operating room (OR) the criterion standard for preoxygenation is an anesthetic circuit and well-fitting face mask, which provide a high fractional inspired oxygen concentration (FiO2 ). Outside of the OR, various strategies exist to provide preoxygenation. The objective was to evaluate the effectiveness of commonly used preoxygenation strategies outside of the OR environment.

METHODS

This was a prospective randomized unblinded study of 30 healthy staff volunteers from a major trauma center emergency department (ED) in Sydney, Australia. The main outcome measure is fractional expired oxygen concentration (FeO2 ) measured after a 3-minute period of tidal volume breathing with seven different preoxygenation strategies.

RESULTS

The mean FeO2 achieved with the anesthetic circuit was 81.0% (95% confidence interval [CI] = 78.3% to 83.6%), bag-valve-mask (BVM) 80.1% (95% CI = 76.5% to 83.6%), BVM with nasal cannula (NC) 74.8% (95% CI = 72.0% to 77.6%), BVM with positive end-expiratory pressure valve (PEEP) 78.9% (95% CI = 75.4% to 82.3%), BVM + NC + PEEP 75.5% (95% CI = 72.2% to 78.9%), nonrebreather mask (NRM) 51.6% (95% CI = 48.8% to 54.4%), and NRM + NC 57.1% (95% CI = 52.9% to 61.2%). Preoxygenation efficacy with BVM strategies was significantly greater than NRM strategies (p < 0.01) and noninferior to the anesthetic circuit.

CONCLUSIONS

In healthy volunteers, the effectiveness of BVM preoxygenation was comparable to the anesthetic circuit (criterion standard) and superior to preoxygenation with NRM. The addition of NC oxygen, PEEP, or both did not improve the efficacy of the BVM device.

The effectiveness of nasal mask vs face mask ventilation in anesthetized, apneic pediatric subjects over 2 years of age: a randomized controlled trial

BACKGROUND

We hypothesized that anesthetized, apneic children could be ventilated equivalently or more efficiently by nasal mask ventilation (NMV) than face mask ventilation (FMV). The aim of this randomized controlled study was to test this hypothesis by comparing the expiratory tidal volume (Vte) between NMV and FMV.

METHODS

After the induction of anesthesia, 41 subjects, 3-17 years of age without anticipated difficult mask ventilation, were randomly assigned to receive either NMV or FMV with neck extension. Both groups were ventilated with pressure control ventilation (PCV) at 20 cmH2 O of peak inspiratory pressure (PIP) with positive end-expiratory pressure (PEEP) levels of 0, 5, and 10 cmH2 O. An additional mouth closing maneuver (MCM) was applied for the NMV group.

RESULTS

The Vte was higher in the FMV group compared with the NMV group (median difference [95% CI]: 8.4 [5.5-11.6] ml·kg(-1) ; P < 0.001) when MCM was not applied. NMV achieved less PEEP than FMV (median difference [95% CI]: 5.0 [4.3-5.3] cmH2 O at 10 cmH2 O; P < 0.001) though both groups achieved the set PIP level. In the NMV group, MCM markedly increased Vte (median increase [95% CI]: 5.9 [2.5-9.0] ml·kg(-1) ; P < 0.005) and PEEP (median increase [95% CI]: 5.0 [0.6-8.6] cmH2 O at 10 cmH2 O; P < 0.005); however, PEEP was highly variable and lower than that of FMV (median difference [95% CI]: 2.5 [0.8-8.5] cmH2 O at 10 cmH2 O; P < 0.05).

CONCLUSIONS

In anesthetized, apneic children greater than 2 years of age ventilated with an anesthesia ventilator and neck extension, FMV established a greater Vte than NMV regardless of mouth status. NMV could not maintain the set PEEP level due to an air leak from the mouth. The MCM increased the Vte and PEEP.

McGRATH MAC videolaryngoscope versus Macintosh laryngoscope for orotracheal intubation in intensive care patients: the randomised multicentre MACMAN trial study protocol

INTRODUCTION

Critically ill patients with acute respiratory, neurological or cardiovascular failure requiring invasive mechanical ventilation are at high risk of difficult intubation and have organ dysfunctions associated with complications of intubation and anaesthesia such as hypotension and hypoxaemia. The complication rate increases with the number of intubation attempts. Videolaryngoscopy improves elective endotracheal intubation. McGRATH MAC is the lightest videolaryngoscope and the most similar to the Macintosh laryngoscope. The primary goal of this trial was to determine whether videolaryngoscopy increased the frequency of successful first-pass intubation in critically ill patients, compared to direct view Macintosh laryngoscopy.

METHODS AND ANALYSIS

MACMAN is a multicentre, open-label, randomised controlled superiority trial. Consecutive patients requiring intubation are randomly allocated to either the McGRATH MAC videolaryngoscope or the Macintosh laryngoscope, with stratification by centre and operator experience. The expected frequency of successful first-pass intubation is 65% in the Macintosh group and 80% in the videolaryngoscope group. With α set at 5%, to achieve 90% power for detecting this difference, 185 patients are needed in each group (370 in all). The primary outcome is the proportion of patients with successful first-pass orotracheal intubation, compared between the two groups using a generalised mixed model to take the stratification factors into account.

ETHICS AND DISSEMINATION

The study project has been approved by the appropriate ethics committee (CPP Ouest 2, # 2014-A00674-43). Informed consent is not required, as both laryngoscopy methods are considered standard care in France; information is provided before study inclusion. If videolaryngoscopy proves superior to Macintosh laryngoscopy, its use will become standard practice, thereby decreasing first-pass intubation failure rates and, potentially, the frequency of intubation-related complications. Thus, patient safety should benefit. Further studies would be warranted to determine whether videolaryngoscopy is also beneficial in the emergency room and for prehospital emergency care.

TRIAL REGISTRATION NUMBER

NCT02413723; Pre-results.

The Physiologically Difficult Airway

Airway management in critically ill patients involves the identification and management of the potentially difficult airway in order to avoid untoward complications. This focus on difficult airway management has traditionally referred to identifying anatomic characteristics of the patient that make either visualizing the glottic opening or placement of the tracheal tube through the vocal cords difficult. This paper will describe the physiologically difficult airway, in which physiologic derangements of the patient increase the risk of cardiovascular collapse from airway management. The four physiologically difficult airways described include hypoxemia, hypotension, severe metabolic acidosis, and right ventricular failure. The emergency physician should account for these physiologic derangements with airway management in critically ill patients regardless of the predicted anatomic difficulty of the intubation.

Use of the Draeger Apollo to Deliver Bilevel Positive Pressure Ventilation During Awake Frontal Craniotomy for a Patient with Severe Chronic Obstructive Pulmonary Disease

In this case report, we describe the use of the Draeger Apollo anesthesia machine to deliver bilevel positive airway pressure (BiPAP) to a patient with severe chronic obstructive pulmonary disease and a history of lung resection undergoing frontal craniotomy for the removal of a brain tumor under moderate to deep sedation. BiPAP in the perioperative period has been described for purposes of preoxygenation and postextubation recruitment. Although its utility as a mode of ventilation during moderate to deep sedation has been demonstrated, it has not come into widespread use. We describe the intraoperative use of pressure support mode on the anesthesia machine to deliver noninvasive positive pressure ventilation through a standard anesthesia mask. Given its ease of access and effectiveness, it is our belief that intraoperative BiPAP may reduce hypoxemia and/or hypercarbia in patients with chronic obstructive pulmonary disease and obstructive sleep apnea undergoing moderate to deep sedation.

Non-invasive monitoring of oxygen delivery in acutely ill patients: new frontiers

Hypovolemia, anemia and hypoxemia may cause critical deterioration in the oxygen delivery (DO₂). Their early detection followed by a prompt and appropriate intervention is a cornerstone in the care of critically ill patients. And yet, the remedies for these life-threatening conditions, namely fluids, blood and oxygen, have to be carefully titrated as they are all associated with severe side-effects when administered in excess. New technological developments enable us to monitor the components of DO₂ in a continuous non-invasive manner via the sensor of the traditional pulse oximeter. The ability to better assess oxygenation, hemoglobin levels and fluid responsiveness continuously and simultaneously may be of great help in managing the DO₂. The non-invasive nature of this technology may also extend the benefits of advanced monitoring to wider patient populations.

Incidence and Duration of Continuously Measured Oxygen Desaturation During Emergency Department Intubation

STUDY OBJECTIVE

Desaturation during intubation has been associated with serious complications, including dysrhythmias, hemodynamic decompensation, hypoxic brain injury, and cardiac arrest. We seek to determine the incidence and duration of oxygen desaturation during emergency department (ED) rapid sequence intubation.

METHODS

This study included adult rapid sequence intubation cases conducted between September 2011 and July 2012 in an urban, academic, Level I trauma center ED. We obtained continuous vital signs with BedMasterEX data acquisition software. Start and completion times of rapid sequence intubation originated from nursing records. We defined oxygen desaturation as (1) cases exhibiting SpO2 reduction to less than 90% if the starting SpO2 was greater than or equal to 90%, or (2) a further reduction in SpO2 in cases in which starting SpO2 was less than 90%. We used multivariable logistic regression to predict oxygen desaturation during rapid sequence intubation.

RESULTS

During the study period, there were 265 rapid sequence intubation cases. The study excluded 99 cases for failure of electronic data acquisition, inadequate documentation, or poor SpO2 waveform during rapid sequence intubation, and excluded cases managed by anesthesia providers, leaving 166 patients in the analysis. After preoxygenation, starting SpO2 was greater than 93% in 124 of 166 cases (75%) and SpO2 was less than 93% in the remaining 46 cases. Oxygen desaturation occurred in 59 patients (35.5%). The median duration of desaturation was 80 seconds (interquartile range 40, 155). Multivariable analysis demonstrated that oxygen desaturation was associated with preintubation SpO2 less than 93% (odds ratio [OR] 5.1; 95% confidence interval (CI) 2.3 to 11.0), multiple intubation attempts (>1 attempt) (OR 3.4; 95% CI 1.4 to 6.1), and rapid sequence intubation duration greater than 3 minutes (OR 2.7; 95% CI 1.2 to 6.1).

CONCLUSION

In this series, 1 in 3 patients undergoing ED rapid sequence intubation experienced oxygen desaturation for a median duration of 80 seconds. Preintubation saturation less than 93%, multiple intubation attempts, and prolonged intubation time are independently associated with oxygen desaturation. Clinicians should use strategies to prevent oxygen desaturation during ED rapid sequence intubation.

Ventilator Strategies and Rescue Therapies for Management of Acute Respiratory Failure in the Emergency Department

Acute respiratory failure is commonly encountered in the emergency department (ED), and early treatment can have effects on long-term outcome. Noninvasive ventilation is commonly used for patients with respiratory failure and has been demonstrated to improve outcomes in acute exacerbations of chronic obstructive lung disease and congestive heart failure, but should be used carefully, if at all, in the management of asthma, pneumonia, and acute respiratory distress syndrome. Lung-protective tidal volumes should be used for all patients receiving mechanical ventilation, and FiO2 should be reduced after intubation to achieve a goal of less than 60%. For refractory hypoxemia, new rescue therapies have emerged to help improve the oxygenation, and in some cases mortality, and should be considered in ED patients when necessary, as deferring until ICU admission may be deleterious. This review article summarizes the pathophysiology of acute respiratory failure, management options, and rescue therapies including airway pressure release ventilation, continuous neuromuscular blockade, inhaled nitric oxide, and extracorporeal membrane oxygenation.

A Technique for Bronchoscopic Intubation During High-Flow Nasal Cannula Oxygen Therapy

Despite preoxygenation, critical hypoxemia can occur during intubation. We describe a technique of high-flow nasal cannula oxygen support during bronchoscopic intubation.

Use of high-flow nasal cannula oxygen therapy to prevent desaturation during tracheal intubation of intensive care patients with mild-to-moderate hypoxemia

OBJECTIVES

Tracheal intubation of ICU patients is frequently associated with severe hypoxemia. Although noninvasive ventilation reduces desaturation during intubation of severely hypoxemic patients, it does not allow for per-procedure oxygenation and has not been evaluated in mild-to-moderate hypoxemic patients for whom high-flow nasal cannula oxygen may be an alternative. We sought to compare pre- and per-procedure oxygenation with either a nonrebreathing bag reservoir facemask or a high-flow nasal cannula oxygen during tracheal intubation of ICU patients.

DESIGN

Prospective quasi-experimental before-after study (ClinicalTrials.gov: NCT01699880).

SETTING

University hospital medico-surgical ICU.

PATIENTS

All adult patients requiring tracheal intubation in the ICU were eligible.

INTERVENTIONS

In the control (before) period, preoxygenation was performed with a nonrebreathing bag reservoir facemask and in the change of practice (after) period, with high-flow nasal cannula oxygen.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was median lowest SpO2 during intubation, and secondary outcomes were SpO2 after preoxygenation and number of patients with saturation less than 80%. One hundred one patients were included. Median lowest SpO2 during intubation were 94% (83-98.5) with the nonrebreathing bag reservoir facemask versus 100% (95-100) with high-flow nasal cannula oxygen (p < 0.0001). SpO2 values at the end of preoxygenation were higher with high-flow nasal cannula oxygen than with nonrebreathing bag reservoir facemask and were correlated with the lowest SpO2 reached during the intubation procedure (r = 0.38, p < 0.0001). Patients in the nonrebreathing bag reservoir facemask group experienced more episodes of severe hypoxemia (2% vs 14%, p = 0.03). In the multivariate analysis, preoxygenation with high-flow nasal cannula oxygen was an independent protective factor of the occurrence of severe hypoxemia (odds ratio, 0.146; 95% CI, 0.01-0.90; p = 0.037).

CONCLUSIONS

High-flow nasal cannula oxygen significantly improved preoxygenation and reduced prevalence of severe hypoxemia compared with nonrebreathing bag reservoir facemask. Its use could improve patient safety during intubation.

High-flow nasal cannula oxygen during endotracheal intubation in hypoxemic patients: a randomized controlled clinical trial

PURPOSE

Intubation of hypoxemic patients is associated with life-threatening adverse events. High-flow therapy by nasal cannula (HFNC) for preoxygenation before intubation has never been assessed by randomized study. Our objective was to evaluate the efficiency of HFNC for preoxygenation, compared to high fraction-inspired oxygen facial mask (HFFM).

METHODS

Multicenter, randomized, open-labelled, controlled PREOXYFLOW trial (NCT 01747109) in six French intensive care units. Acute hypoxemic adults requiring intubation were randomly allocated to HFNC or HFFM. Patients were eligible if PaO2/FiO2 ratio was below 300 mmHg, respiratory rate at least 30/min and if they required FiO2 50% or more to obtain at least 90% oxygen saturation. HFNC was maintained throughout the procedure, whereas HFFM was removed at the end of general anaesthesia induction. Primary outcome was the lowest saturation throughout intubation procedure. Secondary outcomes included adverse events related to intubation, duration of mechanical ventilation and death.

RESULTS

A total of 124 patients were randomized. In the intent-to-treat analysis, including 119 patients (HFNC n = 62; HFFM n = 57), the median (interquartile range) lowest saturation was 91.5% (80-96) for HFNC and 89.5% (81-95) for the HFFM group (p = 0.44). There was no difference for difficult intubation (p = 0.18), intubation difficulty scale, ventilation-free days (p = 0.09), intubation-related adverse events including desaturation <80% or mortality (p = 0.46).

CONCLUSIONS

Compared to HFFM, HFNC as a preoxygenation device did not reduce the lowest level of desaturation.

High-flow nasal cannula oxygen therapy in adults

High-flow nasal cannula (HFNC) oxygen therapy comprises an air/oxygen blender, an active humidifier, a single heated circuit, and a nasal cannula. It delivers adequately heated and humidified medical gas at up to 60 L/min of flow and is considered to have a number of physiological effects: reduction of anatomical dead space, PEEP effect, constant fraction of inspired oxygen, and good humidification. While there have been no big randomized clinical trials, it has been gaining attention as an innovative respiratory support for critically ill patients. Most of the available data has been published in the neonatal field. Evidence with critically ill adults are poor; however, physicians apply it to a variety of patients with diverse underlying diseases: hypoxemic respiratory failure, acute exacerbation of chronic obstructive pulmonary disease, post-extubation, pre-intubation oxygenation, sleep apnea, acute heart failure, patients with do-not-intubate order, and so on. Many published reports suggest that HFNC decreases breathing frequency and work of breathing and reduces needs of escalation of respiratory support in patients with diverse underlying diseases. Some important issues remain to be resolved, such as its indication, timing of starting and stopping HFNC, and escalating treatment. Despite these issues, HFNC oxygen therapy is an innovative and effective modality for the early treatment of adults with respiratory failure with diverse underlying diseases.

Failed noninvasive positive-pressure ventilation is associated with an increased risk of intubation-related complications

BACKGROUND

Noninvasive positive-pressure ventilation (NIPPV) use has increased in the treatment of patients with respiratory failure. However, despite decreasing the need for intubation in some patients, there are no data regarding the risk of intubation-related complications associated with delayed intubation in adult patients who fail NIPPV. The objective of this study is to evaluate the odds of a composite complication of intubation following failed NIPPV compared to patients intubated primarily in the medical intensive care unit (ICU).

METHODS

This is a single-center retrospective cohort study of 235 patients intubated between 1 January 2012 and 30 June 2013 in a medical ICU of a university medical center. A total of 125 patients were intubated after failing NIPPV, 110 patients were intubated without a trial of NIPPV. Intubation-related data were collected prospectively through a continuous quality improvement (CQI) program and retrospectively extracted from the medical record on all patients intubated on the medical ICU. A propensity adjustment for the factors expected to affect the decision to initially use NIPPV was used, and the adjusted multivariate regression analysis was performed to evaluate the odds of a composite complication (desaturation, hypotension, or aspiration) with intubation following failed NIPPV versus primary intubation.

RESULTS

A propensity-adjusted multivariate regression analysis revealed that the odds of a composite complication of intubation in patients who fail NIPPV was 2.20 (CI 1.14 to 4.25), when corrected for the presence of pneumonia or acute respiratory distress syndrome (ARDS), and adjusted for factors known to increase complications of intubation (total attempts and operator experience). When a composite complication occurred, the unadjusted odds of death in the ICU were 1.79 (95% CI 1.03 to 3.12).

CONCLUSIONS

After controlling for potential confounders, this propensity-adjusted analysis demonstrates an increased odds of a composite complication with intubation following failed NIPPV. Further, the presence of a composite complication during intubation is associated with an increased odds of death in the ICU.

Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways

Emergency and difficult tracheal intubations are hazardous undertakings where successive laryngoscopy-hypoxaemia-re-oxygenation cycles can escalate to airway loss and the 'can't intubate, can't ventilate' scenario. Between 2013 and 2014, we extended the apnoea times of 25 patients with difficult airways who were undergoing general anaesthesia for hypopharyngeal or laryngotracheal surgery. This was achieved through continuous delivery of transnasal high-flow humidified oxygen, initially to provide pre-oxygenation, and continuing as post-oxygenation during intravenous induction of anaesthesia and neuromuscular blockade until a definitive airway was secured. Apnoea time commenced at administration of neuromuscular blockade and ended with commencement of jet ventilation, positive-pressure ventilation or recommencement of spontaneous ventilation. During this time, upper airway patency was maintained with jaw-thrust. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) was used in 15 males and 10 females. Mean (SD [range]) age at treatment was 49 (15 [25-81]) years. The median (IQR [range]) Mallampati grade was 3 (2-3 [2-4]) and direct laryngoscopy grade was 3 (3-3 [2-4]). There were 12 obese patients and nine patients were stridulous. The median (IQR [range]) apnoea time was 14 (9-19 [5-65]) min. No patient experienced arterial desaturation < 90%. Mean (SD [range]) post-apnoea end-tidal (and in four patients, arterial) carbon dioxide level was 7.8 (2.4 [4.9-15.3]) kPa. The rate of increase in end-tidal carbon dioxide was 0.15 kPa.min(-1) . We conclude that THRIVE combines the benefits of 'classical' apnoeic oxygenation with continuous positive airway pressure and gaseous exchange through flow-dependent deadspace flushing. It has the potential to transform the practice of anaesthesia by changing the nature of securing a definitive airway in emergency and difficult intubations from a pressured stop-start process to a smooth and unhurried undertaking.

Airway management in the critically ill

Successful first attempt intubation of the critically ill patient is of extreme importance. While these patients are anatomically and physiologically complicated, making intubation particularly risky, several important steps have recently been shown to improve the chances of a safe first attempt success. Proper evaluation, planning, positioning, preoxygenation, and in select patients the use of a neuromuscular blocking agent have all been shown to be useful for minimizing the difficult intubation and intubation- related complications. Additionally, although there is significant controversy regarding video laryngoscopy, the use of a video laryngoscope as the primary method of intubation has been shown in all cases to be at least as good as, and often more successful than, direct laryngoscopy.

Difficult intubation in obese patients: incidence, risk factors, and complications in the operating theatre and in intensive care units

BACKGROUND

Intubation procedure in obese patients is a challenging issue both in the intensive care unit (ICU) and in the operating theatre (OT). The objectives of the study were (i) to compare the incidence of difficult intubation and (ii) its related complications in obese patients admitted to ICU and OT.

METHODS

We conducted a multicentre prospective observational cohort study in ICU and OT in obese (BMI≥30 kg m(-2)) patients. The primary endpoint was the incidence of difficult intubation. Secondary endpoints were the risk factors for difficult intubation, the use of difficult airway management techniques, and severe life-threatening complications related to intubation (death, cardiac arrest, severe hypoxaemia, severe cardiovascular collapse).

RESULTS

In cohorts of 1400 and 11 035 consecutive patients intubated in ICU and in the OT, 282 (20%) and 2103 (19%) were obese. In obese patients, the incidence of difficult intubation was twice more frequent in ICU than in the OT (16.3% vs 8.2%, P<0.01). In both cohorts, risk factors for difficult intubation were Mallampati score III/IV, obstructive sleep apnoea syndrome, and reduced mobility of cervical spine, while limited mouth opening, severe hypoxaemia, and coma appeared only in ICU. Specific difficult airway management techniques were used in 66 (36%) cases of difficult intubation in obese patients in the OT and in 10 (22%) cases in ICU (P=0.04). Severe life-threatening complications were significantly more frequent in ICU than in the OT (41.1% vs 1.9%, relative risk 21.6, 95% confidence interval 15.4-30.3, P<0.01).

CONCLUSIONS

In obese patients, the incidence of difficult intubation was twice more frequent in ICU than in the OT and severe life-threatening complications related to intubation occurred 20-fold more often in ICU.

CLINICAL TRIAL REGISTRATION

Current controlled trials. Identifier: NCT01532063.

Development of a standard operating procedure and checklist for rapid sequence induction in the critically ill

INTRODUCTION

Rapid sequence induction (RSI) of critically ill patients outside of theatres is associated with a higher risk of hypoxia, cardiovascular collapse and death. In the prehospital and military environments, there is an increasing awareness of the benefits of standardised practice and checklists.

METHODS

We conducted a non-systematic review of literature pertaining to key components of RSI preparation and management. A standard operating procedure (SOP) for in-hospital RSI was developed based on this and experience from large teaching hospital anaesthesia and critical care departments.

RESULTS

The SOP consists of a RSI equipment set-up sheet, pre-RSI checklist and failed airway algorithm. The SOP should improve RSI preparation, crew resource management and first pass intubation success while minimising adverse events.

CONCLUSION

Based on the presented literature, we believe the evidence is sufficient to recommend adoption of the core components in the suggested SOP. This standardised approach to RSI in the critically ill may reduce the current high incidence of adverse events and hopefully improve patient outcomes.

How to preoxygenate in operative room: healthy subjects and situations "at risk"

Intubation is one of the most common procedures performed in operative rooms. It can be associated with life-threatening complications when difficult airway access occurs, in patients who cannot tolerate even a slight hypoxemia or when performed in patients at risk of oxygen desaturation during intubation, as obese, critically-ill and pregnant patients. To improve intubation safety, preoxygenation is a major technique, extending the duration of safe apnoea, defined as the time until a patient reaches an arterial saturation level of 88% to 90%, to allow for placement of a definitive airway. Preoxygenation consists in increasing the lung stores of oxygen, located in the functional residual capacity, and helps preventing hypoxia that may occur during intubation attempts. Obese, critically-ill and pregnant patients are especially at risk of reduced effectiveness of preoxygenation because of pathophysiological modifications (reduced functional residual capacity (FRC), increased risk of atelectasis, shunt). Three minutes tidal volume breathing or 3-8 vital capacities are recommended in general population, mostly allowing achieving a 90% end-tidal oxygen level. Recent studies have indicated that in order to maximize the value of preoxygenation (i.e, oxygenation stores) obese and critically-ill patients can benefit from the combination of breathing 100% oxygen and non-invasive positive pressure ventilation (NIV) with end-expiratory positive pressure (PEEP) in the proclive position (Trendelenburg reverse). Recruitment manoeuvres may be of interest immediately after intubation to limit the risk of lung derecruitment. Further studies are needed in the field of preoxygenation in pregnant women.

Video laryngoscopy versus direct laryngoscopy for orotracheal intubation in the intensive care unit: a systematic review and meta-analysis

PURPOSE

Single studies of video laryngoscopy (VL) use for airway management in intensive care unit (ICU) patients have produced controversial findings. The aim of this study was to critically review the literature to investigate whether VL reduces difficult orotracheal intubation (OTI) rate, first-attempt success, and complications related to intubation in ICU patients, compared to standard therapy, defined as direct laryngoscopy (DL).

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials, as well as prospective and retrospective observational studies, by searching PubMed, EMBASE, and bibliographies of articles retrieved. We screened for relevant studies that enrolled adults in whom the trachea was intubated in the ICU and compared VL to DL. We included studies reporting at least one clinical outcome of interest to perform a meta-analysis. We generated pooled odd ratios (OR) across studies. The primary outcome measure was difficult OTI. The secondary outcomes were first-attempt success, Cormack 3/4 grades, and complications related to intubation (severe hypoxemia, severe cardiovascular collapse, airway injury, esophageal intubation).

RESULTS

Nine trials with a total of 2,133 participants (1,067 in DL and 1,066 in VL) were included in the current analysis. Compared to DL, VL reduced the risk of difficult OTI [OR 0.29 (95% confidence interval (CI) 0.20-0.44, p < 0.001)], Cormack 3/4 grades [OR 0.26 (95% CI 0.17-0.41, p < 0.001)], and esophageal intubation [0.14 (95% CI 0.02-0.81, p = 0.03)] and increased the first-attempt success [OR 2.07 (95% CI 1.35-3.16, p < 0.001)]. No statistically significant difference was found for severe hypoxemia, severe cardiovascular collapse or airway injury.

CONCLUSIONS

These results suggest that VL could be useful in airway management of ICU patients.

Mechanical ventilation and clinical practice heterogeneity in intensive care units: a multicenter case-vignette study

BACKGROUND

Observational studies on mechanical ventilation (MV) show practice variations across ICUs. We sought to determine, with a case-vignette study, the heterogeneity of processes of care in ICUs focusing on mechanical ventilation procedures, and whether organizational patterns or physician characteristics influence practice variations.

METHODS

We conducted a cross-sectional multicenter study using the case-vignette methodology. Descriptive analyses were calculated for each organizational pattern and respondent characteristics. An Index of Qualitative Variation (IQV, from 0, no heterogeneity, to a maximum of 1) was calculated.

RESULTS

Forty ICUs from France (N = 33) and Switzerland (N = 7) participated; 396 physicians answered our case-vignettes. There was major heterogeneity of management processes related to MV within and across centers (mean IQV per center 0.51, SD 0.09). We observed the lowest variability (mean IQV per question < 0.4) for questions related to intubation procedure, ventilation of acute respiratory distress syndrome and the use of the semirecumbent position. We observed a high variability (mean IQV per question > 0.6) for questions related to management of endotracheal tube or suctioning, management of sedation and analgesia, and respect of autonomy. Heterogeneity was independent of respondent characteristics and of the presence of written procedures. There was a correlation between the processes associated with the highest variability (mean IQV per question > 0.6) and the annual volume of ICU admission (r = 0.32 (0.01 to 0.58)) and MV (r = 0.38 (0.07 to 0.63)). Within ICUs there was a large heterogeneity regarding knowledge of a local written procedure.

CONCLUSIONS

Large clinical practice variations were found among ICUs. High volume centers were more likely to have heterogeneous practices. The presence of a local written procedure or respondent characteristics did not influence practice variation.

Bronchoscopic intubation during continuous nasal positive pressure ventilation in the treatment of hypoxemic respiratory failure

Endotracheal intubation is difficult in patients with hypoxemic respiratory failure who deteriorate despite treatment with noninvasive positive pressure ventilation (NIPPV). Maintaining NIPPV during intubation may prevent alveolar derecruitment and deterioration in gas exchange. We report a case series of 10 nonconsecutive patients with NIPPV failure who were intubated via a flexible bronchoscope during nasal mask positive pressure ventilation. All 10 patients were intubated in the first attempt. Hypotension was the most frequent complication (33%). Mean decrease in oxyhemoglobin saturation during the procedure was 4.7 ± 3.1. This method of intubation may extend the benefits of preoxygenation throughout the whole process of endotracheal intubation. It requires an experienced operator and partially cooperative patients. A prospective trial is necessary to determine the best intubation method for NIPPV failure.

Video laryngoscopy improves intubation success and reduces esophageal intubations compared to direct laryngoscopy in the medical intensive care unit

Introduction

Tracheal intubation in the Intensive Care Unit (ICU) can be challenging as patients often have anatomic and physiologic characteristics that make intubation particularly difficult. Video laryngoscopy (VL) has been shown to improve first attempt success compared to direct laryngoscopy (DL) in many clinical settings and may be an option for ICU intubations.

Methods

All intubations performed in this academic medical ICU during a 13-month period were entered into a prospectively collected quality control database. After each intubation, the operator completed a standardized form evaluating multiple aspects of the intubation including: patient demographics, difficult airway characteristics (DACs), method and device(s) used, medications used, outcomes and complications of each attempt. Primary outcome was first attempt success. Secondary outcomes were grade of laryngoscopic view, ultimate success, esophageal intubations, and desaturation. Multivariate logistic regression was performed for first attempt and ultimate success.

Results

Over the 13-month study period (January 2012-February 2013), a total of 234 patients were intubated using VL and 56 patients were intubated with DL. First attempt success for VL was 184/234 (78.6%; 95% CI 72.8 to 83.7) while DL was 34/56 patients (60.7%; 95% CI 46.8 to 73.5). Ultimate success for VL was 230/234 (98.3%; 95% CI 95.1 to 99.3) while DL was 52/56 patients (91.2%; 95% CI 81.3 to 97.2). In the multivariate regression model, VL was predictive of first attempt success with an odds ratio of 7.67 (95% CI 3.18 to 18.45). VL was predictive of ultimate success with an odds ratio of 15.77 (95% CI 1.92 to 129). Cormack-Lehane I or II view occurred 199/234 times (85.8%; 95% CI 79.5 to 89.1) and a median POGO (Percentage of Glottic Opening) of 82% (IQR 60 to 100) with VL, while Cormack-Lehane I or II view occurred 34/56 times (61.8%; 95% CI 45.7 to 71.9) and a median POGO of 45% (IQR 0 to 78%) with DL. VL reduced the esophageal intubation rate from 12.5% with DL to 1.3% (P = 0.001) but there was no difference in desaturation rates.

Conclusions

In the medical ICU, video laryngoscopy resulted in higher first attempt and ultimate intubation success rates and improved grade of laryngoscopic view while reducing the esophageal intubation rate compared to direct laryngoscopy.

Techniques for the difficult airway

PURPOSE OF REVIEW

Management of the difficult airway is associated with significant morbidity and mortality in critically ill patients. An increasing array of advanced airway tools are available, but appropriate selection and application in the ICU remains poorly defined.

RECENT FINDINGS

Difficult airway incidence during emergent intubation is 10%, but complications of ICU airway management remain common. Training and equipment in many ICUs remain variable despite data that demonstrate that an 'intubation management bundle' and a systematic approach to teamwork and training can reduce life-threatening airway complications. A protocol employing an extraglottic airway (EGA) early in cases of inadequate ventilation has been associated with no episodes of prolonged hypoxemia in 12 225 consecutive intubations. Direct laryngoscopy with gum elastic bougie is the most commonly employed method to manage emergent difficult airways, and videolaryngoscopes also provide greater glottic visualization and a high rate of intubation success in patients with difficult airway risk factors or a failed airway.

SUMMARY

A systematic approach to intubation that emphasizes planning and teamwork can reduce intubation complications. Early use of an EGA or cricothyroidotomy may reduce complications when oxygenation is inadequate. Use of a gum elastic bougie or indirect optical device is also associated with a high rate of intubation success when oxygenation permits.

[High flow, humidified-reheated oxygen therapy: a new oxygenation technique for adults]

Currently conventional oxygen therapy is the first choice symptomatic treatment in the management of acute respiratory failure (ARF). However, conventional oxygen therapy has important limitations which have lead to the development of heated and humidified high-flow nasal oxygen therapy (HFNO). HFNO is an innovative technique that can deliver, through special nasal cannulae, up to 100% of the inspired fraction (FiO2) with heated and humidified oxygen at a maximum flow of 70L/min. The characteristics of this technique (overcoming the patient's spontaneous inspiratory flow, heated humidification,) and its physiological effects (no dilution of FiO2, positive end-expiratory pressure, pharyngeal dead-space washout, decrease in airway resistance), allow efficient optimization of oxygenation with better tolerance for patients. Current data, mainly observational, show that HFNO could be used particularly for the management of hypoxemic ARF, notably in the more severe forms. Indications for using HFNO, alone or in association with noninvasive ventilation, are potentially very broad and may involve different types of ARF (post-operative, post-extubation, palliative care) and even the practice of invasive technical procedures (bronchial fibroscopy). However, though current studies are very encouraging and promise a clinical benefit on patient outcomes, randomized trials are still needed to demonstrate that HFNO avoids the need for endotracheal intubation in the management of ARF.