Preoxygenation and prevention of desaturation during emergency airway management

Preoxygenation and apneic oxygenation using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange for emergency intubation

PURPOSE

Hypoxia is one of the leading causes of anesthesia-related injury. In response to the limitations of conventional preoxygenation, Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) has been used as a method of providing both preoxygenation and apneic oxygenation during intubation.

MATERIALS AND METHODS

In this prospective, observational study, THRIVE was introduced in a critical care unit (CCU), operating room (OR), and emergency department (ED) during emergency intubation of patients at high risk of hypoxia. Linear regression analysis tested for correlation between apnea time or body mass index and hemoglobin saturation (Spo₂).

RESULTS

Across 71 sequential patients, the interquartile range for apnea time and decrease in Spo₂ were 60 to 125 seconds and 0% to 3%, respectively. Significant desaturation occurred in 5 (7%) patients. There was no evidence of correlation between apnea time or body mass index and Spo₂ (R²=0.04 and 0.08 for CCU/ED and OR and 0.01 and 0.04 CCU/ED and OR, respectively). There were no complications reported from using THRIVE.

CONCLUSIONS

This study demonstrated that preoxygenation and apneic oxygenation using THRIVE were associated with a low incidence of desaturation during emergency intubation of patients at high risk of hypoxia in the CCU, OR, and ED. THRIVE has the potential to minimize the risk of hypoxia in these patient groups.

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).

First Pass Success Without Hypoxemia Is Increased With the Use of Apneic Oxygenation During Rapid Sequence Intubation in the Emergency Department

OBJECTIVES

The objective was to determine the effect of apneic oxygenation (AP OX) on first pass success without hypoxemia (FPS-H) in adult patients undergoing rapid sequence intubation (RSI) in the emergency department (ED).

METHODS

Continuous quality improvement data were prospectively collected on all patients intubated in an academic ED from July 1, 2013, to June 30, 2015. During this period the use of AP OX was introduced and encouraged for all patients undergoing RSI in the ED. Following each intubation, the operator completed a standardized data form that included information on patient, operator, and intubation characteristics. Adult patients 18 years of age or greater who underwent RSI in the ED by emergency medicine residents were included in the analysis. The primary outcome was FPS-H, which was defined as successful tracheal intubation on a single laryngoscope insertion without oxygen saturation falling below 90%. A multivariate logistic regression analysis was performed to determine the effect of AP OX on FPS-H.

RESULTS

During the 2-year study period, 635 patients met inclusion criteria. Of these, 380 (59.8%) had AP OX utilized and 255 (40.2%) had no AP OX utilized. In the AP OX cohort the FPS-H was 312/380 (82.1%) and in the no AP OX cohort the FPS-H was 176/255 (69.0%) (difference = 13.1%, 95% confidence interval [CI] = 6.2% to 19.9%). In the multivariate logistic regression analysis, the use of AP OX was associated with an increased odds of FPS-H (adjusted odds ratio = 2.2, 95% CI = 1.5 to 3.3).

CONCLUSIONS

The use of AP OX during the RSI of adult patients in the ED was associated with a significant increase in FPS-H. These results suggest that the use of AP OX has the potential to increase the safety of RSI in the ED by reducing the number of intubation attempts and the incidence of hypoxemia.

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.

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.

Apneic preoxygenation without nasal prongs: the "Hungarian Air Ambulance method"

The Hungarian Air Ambulance has recently adopted oxygen supplementation during laryngoscopy, also known as apneic preoxygenation, to prevent desaturation during rapid sequence intubation. Despite its simplicity the nasal cannula method has some limitations relevant to our practice. First, the cannula can dislodge if the head is manipulated during preparation or intubation, especially if nasopharyngeal airways are chosen to maximise preoxygenation. Second, the method is incompatible with continuous nasal suctioning required in severe maxillofacial trauma. Third, if only one oxygen source and one competent assistant is available, a situation common during prehospital missions, the extra tube swap needed for continuous oxygen supplementation makes the procedure more complex and prone to error. We report a new method that provides comparable oxygen supplementation to the nasal cannula method, but at the same time eliminates the problems mentioned above and is easier and quicker to perform. It requires the intubator to cut and insert the tubing of the non-rebreather mask into the nasopharyngeal airway, thus providing direct pharyngeal insufflation. The method is applicable to every patient who has at least one nasopharyngeal airway inserted at the time of laryngoscopy and it only requires a pair of scissors.

Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of difficult and failed tracheal intubation in obstetrics

The Obstetric Anaesthetists' Association and Difficult Airway Society have developed the first national obstetric guidelines for the safe management of difficult and failed tracheal intubation during general anaesthesia. They comprise four algorithms and two tables. A master algorithm provides an overview. Algorithm 1 gives a framework on how to optimise a safe general anaesthetic technique in the obstetric patient, and emphasises: planning and multidisciplinary communication; how to prevent the rapid oxygen desaturation seen in pregnant women by advocating nasal oxygenation and mask ventilation immediately after induction; limiting intubation attempts to two; and consideration of early release of cricoid pressure if difficulties are encountered. Algorithm 2 summarises the management after declaring failed tracheal intubation with clear decision points, and encourages early insertion of a (preferably second-generation) supraglottic airway device if appropriate. Algorithm 3 covers the management of the 'can't intubate, can't oxygenate' situation and emergency front-of-neck airway access, including the necessity for timely perimortem caesarean section if maternal oxygenation cannot be achieved. Table 1 gives a structure for assessing the individual factors relevant in the decision to awaken or proceed should intubation fail, which include: urgency related to maternal or fetal factors; seniority of the anaesthetist; obesity of the patient; surgical complexity; aspiration risk; potential difficulty with provision of alternative anaesthesia; and post-induction airway device and airway patency. This decision should be considered by the team in advance of performing a general anaesthetic to make a provisional plan should failed intubation occur. The table is also intended to be used as a teaching tool to facilitate discussion and learning regarding the complex nature of decision-making when faced with a failed intubation. Table 2 gives practical considerations of how to awaken or proceed with surgery. The background paper covers recommendations on drugs, new equipment, teaching and training.

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.

Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults

These guidelines provide a strategy to manage unanticipated difficulty with tracheal intubation. They are founded on published evidence. Where evidence is lacking, they have been directed by feedback from members of the Difficult Airway Society and based on expert opinion. These guidelines have been informed by advances in the understanding of crisis management; they emphasize the recognition and declaration of difficulty during airway management. A simplified, single algorithm now covers unanticipated difficulties in both routine intubation and rapid sequence induction. Planning for failed intubation should form part of the pre-induction briefing, particularly for urgent surgery. Emphasis is placed on assessment, preparation, positioning, preoxygenation, maintenance of oxygenation, and minimizing trauma from airway interventions. It is recommended that the number of airway interventions are limited, and blind techniques using a bougie or through supraglottic airway devices have been superseded by video- or fibre-optically guided intubation. If tracheal intubation fails, supraglottic airway devices are recommended to provide a route for oxygenation while reviewing how to proceed. Second-generation devices have advantages and are recommended. When both tracheal intubation and supraglottic airway device insertion have failed, waking the patient is the default option. If at this stage, face-mask oxygenation is impossible in the presence of muscle relaxation, cricothyroidotomy should follow immediately. Scalpel cricothyroidotomy is recommended as the preferred rescue technique and should be practised by all anaesthetists. The plans outlined are designed to be simple and easy to follow. They should be regularly rehearsed and made familiar to the whole theatre team.

Apneic Oxygenation during Rapid Sequence Intubation in Critically Ill Children

This prospective case series documented hypoxemia and potential complications associated with apneic oxygenation in critically ill pediatric patients during rapid sequence intubation. Forty-four patients received apneic oxygenation via nasal cannula at rates of 5, 10, and 15 L/min for ages <4, 4 to 12, and 12 to 18 years, respectively. Pre- and postintubation attempt mean Spo ₂ were 98.9 ± 2.95 and 90.7 ± 1.95%, respectively. Postintubation Spo ₂ < 80% were significantly less with one intubation attempt, compared with multiple attempts (p < 0.001). No serious complications were noted. Apneic oxygenation was well tolerated in critically ill children.

Prospective observational study of emergency airway management in the critical care environment of a tertiary hospital in Melbourne

The objective of this study is to describe the population of patients receiving emergency airway management outside operating theatres at our institution, a tertiary referral centre in Melbourne. A registry of all patients receiving emergency airway management in the emergency department, ICU and on the wards as part of Medical Emergency Response teams' care, was prospectively collected. There were 128 adults and one paediatric patient requiring emergency airway management recruited to the study. Data for analysis included patient demographics, pre-oxygenation and apnoeic oxygenation, staff, drugs, details of laryngoscopic attempts, adjuncts, airway manoeuvres, complications sustained and method of confirmation of endotracheal tube placement. Over a 12-month period, there were 139 intubations of 129 patients, requiring a total of 169 attempts. Respiratory failure was the most common indication for intubation. Intubation was successful on the first episode of laryngoscopy in 116 (83.5%) patients. Complications occurred in 48 patients. In the cohort of patients without respiratory failure, nasal cannulae apnoeic oxygenation significantly reduced the incidence of hypoxaemia (0 out of 31 [0.0%] versus 10 out of 60 [16.7%], P=0.016; absolute risk reduction 16.7%; number needed to treat: 6). Waveform capnography was used to confirm endotracheal tube placement in 133 patients and there were four episodes of oesophageal intubation, all of which were recognised immediately. In the critical care environment of our institution, emergency airway management is achieved with a first-attempt success rate that is comparable to overseas data. Nasal cannulae apnoeic oxygenation appears to significantly reduce the risk of hypoxaemia in patients without respiratory failure and the use of waveform capnography eliminates episodes of unrecognised oesophageal intubation.

A preprocedural checklist improves the safety of emergency department intubation of trauma patients

OBJECTIVES

Endotracheal intubation of trauma patients is a vital and high-risk procedure in the emergency department (ED). The hypothesis was that implementation of a standardized, preprocedural checklist would improve the safety of this procedure.

METHODS

A preprocedural intubation checklist was developed and then implemented in a prospective pre-/postinterventional study in an academic trauma center ED. The proportions of trauma patients older than 16 years who experienced intubation-related complications during the 6 months before checklist implementation and 6 months after implementation were compared. Intubation-related complications included oxygen desaturation, emesis, esophageal intubation, hypotension, and cardiac arrest. Additional outcomes included time from paralysis to intubation and adherence to safety process measures.

RESULTS

During the study, 141 trauma patients were intubated, including 76 in the prechecklist period and 65 in the postchecklist period. A lower proportion of patients experienced intubation-related complications in the postchecklist period (1.5%) than the prechecklist period (9.2%), representing a 7.7% (95% confidence interval = 0.5% to 14.8%) absolute risk reduction. Paralysis-to-intubation time was also lower in the postchecklist period (median = 82 seconds, interquartile range [IQR] = 68 to 101 seconds) compared to the prechecklist period (median = 94 seconds, IQR = 78 to 115 seconds; p = 0.02). Adherence to safety process measures also improved, with all safety measures performed in 69.2% in the postchecklist period compared to 17.1% before the checklist (p < 0.01).

CONCLUSIONS

Implementation of a preintubation checklist for ED intubation of trauma patients was associated with a reduction in intubation-related complications, decreased paralysis-to-intubation time, and improved adherence to recognized safety measures.

Anaesthesiologist-provided prehospital airway management in patients with traumatic brain injury: an observational study

Background

Guidelines recommend that patients with brain trauma with a Glasgow Coma Scale (GCS) score of less than 9 should have an airway established. Hypoxia, hypotension and hypertension as well as hypoventilation and hyperventilation may worsen outcome in these patients.

Objectives

The objectives were to investigate guideline adherence, reasons for nonadherence and the incidences of complications related to prehospital advanced airway management in patients with traumatic brain injury.

Materials and methods

We prospectively collected data from eight anaesthesiologist-staffed prehospital critical care teams in the Central Denmark Region according to the Utstein-style template.

Results

Among 1081 consecutive prehospital advanced airway management patients, we identified 54 with a traumatic brain injury and an initial GCS score of less than 9. Guideline adherence in terms of airway management was 92.6%. The reasons for nonadherence were the patient’s condition, anticipated difficult airway management and short distance to the emergency department. Following rapid sequence intubation (RSI), 11.4% developed oxygen saturation below 90%, 9.1% had a first post-RSI systolic blood pressure below 90 mmHg and 48.9% had a first post-RSI systolic blood pressure below 120 mmHg. The incidence of hypertension following prehospital RSI was 4.5%. The incidence of postendotracheal intubation hyperventilation was as high as 71.1%.

Conclusion

The guideline adherence was high. The incidences of post-RSI hypoxia and systolic blood pressure below 90 compare with the results reported from other physician-staffed prehospital services. The incidence of systolic blood pressure below 120 as well as that of hyperventilation following prehospital endotracheal intubation in patients with traumatic brain injury call for a change in our current practice.

Comparisons of the Pentax-AWS, Glidescope, and Macintosh Laryngoscopes for Intubation Performance during Mechanical Chest Compressions in Left Lateral Tilt: A Randomized Simulation Study of Maternal Cardiopulmonary Resuscitation

Purpose. Rapid advanced airway management is important in maternal cardiopulmonary resuscitation (CPR). This study aimed to compare intubation performances among Pentax-AWS (AWS), Glidescope (GVL), and Macintosh laryngoscope (MCL) during mechanical chest compression in 15° and 30° left lateral tilt. Methods. In 19 emergency physicians, a prospective randomized crossover study was conducted to examine the three laryngoscopes. Primary outcomes were the intubation time and the success rate for intubation. Results. The median intubation time using AWS was shorter than that of GVL and MCL in both tilt degrees. The time to visualize the glottic view in GVL and AWS was significantly lower than that of MCL (all P < 0.05), whereas there was no significant difference between the two video laryngoscopes (in 15° tilt, P = 1; in 30° tilt, P = 0.71). The progression of tracheal tube using AWS was faster than that of MCL and GVL in both degrees (all P < 0.001). Intubations using AWS and GVL showed higher success rate than that of Macintosh laryngoscopes. Conclusions. The AWS could be an appropriate laryngoscope for airway management of pregnant women in tilt CPR considering intubation time and success rate.

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.

Factors associated with oxyhemoglobin desaturation during rapid sequence intubation in a pediatric emergency department: findings from multivariable analyses of video review data

OBJECTIVES

In a video-based study of rapid sequence intubation (RSI) in a pediatric emergency department (PED), 33% of children experienced oxyhemoglobin desaturation (SpO2 < 90%). To inform targeted improvement interventions, we planned multivariable analyses to identify patient and process variables (including time-based data around performance of key RSI process elements uniquely available from video review) associated with desaturation during pediatric RSI.

METHODS

These were planned analyses of data collected during a retrospective, video-based study of RSI in a high-volume, academic PED. For variables with plausible associations with desaturation, multiple logistic regression and generalized estimating equations were used to identify those characteristics independently associated with desaturation at both the patient and the attempt levels.

RESULTS

The authors analyzed video data from 114 patients undergoing RSI over 12 months. Desaturation was more common in patients 24 months of age and younger (59%) than in patients older than 24 months of age (10%). Variables associated with desaturation in patients 24 months of age and younger were duration of attempts (both individual and cumulative), the occurrence of esophageal intubation, a respiratory indication for intubation, and young age. The receiver operating characteristics curve for the model had an area under the curve of 0.80 (95% confidence interval [CI] = 0.67 to 0.92). Forty-six percent of desaturations occurred after 45 seconds of laryngoscopy, and 82% after 30 seconds. The odds ratio for desaturation on individual attempts lasting longer than 30 seconds (vs. those 30 seconds or less) was 5.7 (95% CI = 2.26 to 14.36).

CONCLUSIONS

For children 24 months of age or younger undergoing RSI in a PED, respiratory indication for intubation, esophageal intubation, and duration of laryngoscopy (both individual and cumulative) were associated with desaturation; the number of attempts was not. Interventions to limit attempt duration in the youngest children may improve the safety of RSI.

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.

Mechanical ventilation of the anesthetized patient

Patients who require general anesthesia to undergo a surgical procedure often require mechanical ventilation during the perioperative period. Ventilators incorporated into modern anesthesia machines offer various options for patient management. The unique effects of general anesthesia and surgery on pulmonary physiology must be considered when selecting an individualized plan for mechanical ventilation during the perioperative period. In this article, the pulmonary effects of general anesthesia are reviewed and available options for mechanical ventilation of the anesthetized patient during the perioperative period are presented.

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.

The safety of general anaesthesia in paediatric patients undergoing the application of Biobrane® for small scalds

BACKGROUND

Each year more than 5000 children present to English and Welsh hospitals for the management of scalds; 60% of these are small scalds of less than 10% body surface area. There are no agreed UK care pathways for this injury. One method of management is to use a biosynthetic wound dressing after thorough wound cleaning. In children, this usually utilises general anaesthesia. This study investigates the incidence of adverse events during anaesthesia for the application of biosynthetic dressings in children with small-area scalds.

METHODS

The medical records of 500 consecutive admissions to a tertiary care paediatric burn centre between July 1st 2007 and June 30th 2012 were analysed. The primary outcome was any patient-related adverse event incurred as a result of the general anaesthesia. Secondary outcomes included delays in discharge and any recovery sequelae to the adverse events.

RESULTS

There were 21 (4.2%) documented adverse events associated with 500 episodes of anaesthesia. Of these, the majority (52%) were documented as self-resolving laryngospasm. All episodes were temporary with no recovery sequelae and did not delay discharge from the post-anaesthetic recovery area.

CONCLUSIONS

The use of general anaesthesia in this setting for the application of biosynthetic dressings in children with small-area scalds has a low incidence of anaesthesia-related complications with no associated long-term sequelae. This incidence is similar to that quoted for adverse events related to anaesthesia for other procedures and is lower than that reported for procedures using sedation.

Reintubation in critically ill patients: procedural complications and implications for care

Introduction

In critically ill patients, re-intubation is common and may be a high-risk procedure. Anticipating a difficult airway and identifying high-risk patients can allow time for life-saving preparation. Unfortunately, prospective studies have not compared the difficulty or complication rates associated with reintubation in this population.

Methods

We performed a secondary analysis of a prospective registry of in-hospital emergency airway management, focusing on patients that underwent multiple out-of-operating room intubations during a single hospitalization. Our main outcomes of interest were technical difficulty of intubation (number of attempts, need for adjuncts to direct laryngoscopy, best Cormack-Lehane grade and training level of final intubator) and the frequency of procedural complications (aspiration, arrhythmia, airway trauma, new hypotension, new hypoxia, esophageal intubation and cardiac arrest). We compared the cohort of reintubated patients to a matched cohort of singly intubated patients and compared each repeatedly intubated patient’s first and last intubation.

Results

Our registry included 1053 patients, of which 151 patients (14%) were repeatedly intubated (median two per patient). Complications were significantly more common during last intubation compared to first (13% versus 5%, P = 0.02). The most common complications were hypotension (41%) and hypoxia (35%). These occurred despite no difference in any measure of technical difficultly across intubations.

Conclusion

In this cohort of reintubated patients, clinically important procedural complications were significantly more common on last intubation compared to first.

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.

Preventing and Treating Hypoxia: Using a Physiology Simulator to Demonstrate the Value of Pre-Oxygenation and the Futility of Hyperventilation

INTRODUCTION

Insufficient pre-oxygenation before emergency intubation, and hyperventilation after intubation are mistakes that are frequently observed in and outside the operating room, in clinical practice and in simulation exercises. Physiological parameters, as appearing on standard patient monitors, do not alert to the deleterious effects of low oxygen saturation on coronary perfusion, or that of low carbon dioxide concentrations on cerebral perfusion. We suggest the use of HumMod, a computer-based human physiology simulator, to demonstrate beneficial physiological responses to pre-oxygenation and the futility of excessive minute ventilation after intubation.

METHODS

We programmed HumMod, to A.) compare varying times (0-7 minutes) of pre-oxygenation on oxygen saturation (SpO2) during subsequent apnoea; B.) simulate hyperventilation after apnoea. We compared the effect of different minute ventilation rates on SpO2, acid-base status, cerebral perfusion and other haemodynamic parameters.

RESULTS

A.) With no pre-oxygenation, starting SpO2 dropped from 98% to 90% in 52 seconds with apnoea. At the other extreme, following full pre-oxygenation with 100% O2 for 3 minutes or more, the SpO2 remained 100% for 7.75 minutes during apnoea, and dropped to 90% after another 75 seconds. B.) Hyperventilation, did not result in more rapid normalization of SpO2, irrespective of the level of minute ventilation. However, hyperventilation did cause significant decreases in cerebral blood flow (CBF).

CONCLUSIONS

HumMod accurately simulates the physiological responses compared to published human studies of pre-oxygenation and varying post intubation minute ventilations, and it can be used over wider ranges of parameters than available in human studies and therefore available in the literature.

The prehospital management of traumatic brain injury

Traumatic brain injury (TBI) is an important cause of death and disability, particularly in younger populations. The prehospital evaluation and management of TBI is a vital link between insult and definitive care and can have dramatic implications for subsequent morbidity. Following a TBI the brain is at high risk for further ischemic injury, with prehospital interventions targeted at reducing this secondary injury while optimizing cerebral physiology. In the following chapter we discuss the prehospital assessment and management of the brain-injured patient. The initial evaluation and physical examination are discussed with a focus on interpretation of specific physical examination findings and interpretation of vital signs. We evaluate patient management strategies including indications for advanced airway management, oxygenation, ventilation, and fluid resuscitation, as well as prehospital strategies for the management of suspected or impending cerebral herniation including hyperventilation and brain-directed hyperosmolar therapy. Transport decisions including the role of triage models and trauma centers are discussed. Finally, future directions in the prehospital management of traumatic brain injury are explored.

Endotracheal intubation in the pediatric emergency department

BACKGROUND AND OBJECTIVES

Prospective safety data on emergency department (ED) intubation in children are limited. We aimed to describe the practice and adverse events associated with endotracheal intubation in a large urban pediatric ED.

METHODS

Prospective observational study at a tertiary pediatric ED with an annual census of 82,000. The primary outcome measure was the adverse event rate. Secondary outcome measures were incidence of difficult laryngoscopy and first pass success rate without desaturation or hypotension.

RESULTS

Over a 12-month period in 2013, there were 71 intubations in 66 patients (9/10,000 ED visits). Median age was 3 years, with 25% in infants <1 year of age. Indications were as follows: trauma (21%) and medical conditions (79%); most frequently status epileptics (31%). Forty-four percent had cardiovascular compromise, 87% had respiratory compromise, and 70% had a GCS <9 prior to intubation. Adverse events occurred in 39%, the most common being hypotension (21%) and desaturation (14%). One anticipated and one unanticipated difficult laryngoscopy were encountered (both Cormack and Lehane grade 3). Overall first pass success rate was 78%, although first pass success without desaturation or hypotension was only 49%. Seven percent required more than two attempts for successful intubation.

CONCLUSION

Intubation of children in the ED is a low-frequency, high-risk procedure. The incidence of adverse events, particularly desaturation and hypotension, is high. The incidence of difficult laryngoscopy is low. First pass success rate without desaturation or hypotension is low. Strategies to avoid desaturation and hypotension in the peri-intubation setting should be prioritized.

A randomized trial on subject tolerance and the adverse effects associated with higher- versus lower-flow oxygen through a standard nasal cannula

STUDY OBJECTIVE

Experts advocate the use of a standard nasal cannula to provide oxygen at flow rates of up to 15 L/minute during emergency intubation. However, because of concerns about potential patient discomfort, some providers avoid providing nasal cannula oxygen at flow rates greater than 6 L/minute. This trial is designed to determine the participants' ability to tolerate 10 minutes of nasal cannula oxygen at higher flow rates.

METHODS

This was a prospective, randomized, crossover trial of healthy volunteers at an emergency department in New Zealand. Participants were randomized to first receive either higher-flow (15 L/minute) or lower-flow (6 L/minute) nasal cannula oxygen for 10 minutes. After a 1-hour washout period, they received the alternate flow rate for 10 minutes. The primary outcome was the ability to tolerate 10 minutes of the nasal cannula oxygen at each flow rate. The secondary outcome was the difference in discomfort between the flow rates as measured on a 100-mm visual analog scale.

RESULTS

All 77 of the participants (100%) were able to tolerate 10 minutes at both flow rates. Participants rated the higher-flow nasal cannula oxygen as a mean of 25 mm (SD 20 mm) more uncomfortable than the lower-flow nasal cannula oxygen. One minute after the oxygen was discontinued, the mean difference in discomfort between the flow rates was a clinically insignificant 9.8 mm (SD 17 mm) more uncomfortable. There were no adverse events.

CONCLUSION

Participants were able to tolerate higher-flow nasal cannula oxygen for 10 minutes without difficulty. Higher-flow nasal cannula oxygen at 15 L/minute was associated with some discomfort, but the discomfort quickly dissipated and caused no adverse events.

A dual-use laryngoscope to facilitate apneic oxygenation

BACKGROUND

In preoxygenated patients, time until oxygen saturation drops can be extended by insufflating oxygen into their airways, thus oxygenating them apneically.

OBJECTIVES

To compare different methods of apneic oxygenation.

METHODS

A noncommercial dual-use laryngoscope with an internal lumen in its blade was used to provide oxygen insufflation into a simulated laryngeal space during intubation. In this experimental study, oxygen insufflation via the dual-use laryngoscope was compared with no oxygen insufflation, with nasal oxygen insufflation, and with direct intratracheal oxygen insufflation. In a preoxygenated test lung of a manikin, oxygen percentage decrease was measured over a 20-min observation period for each method of oxygen application.

RESULTS

Oxygen percentage in the test lung dropped from 97% to 37 ± 1% in the control group (p < 0.001 compared to all other groups) and to 68 ± 1% in the nasal insufflation group (p < 0.001 compared to all other groups). Oxygen percentage remained over 90% in both the direct intratracheal insufflation group (96 ± 0%) and the laryngoscope blade insufflation group (94 ± 1%) (p < 0.01 between the latter two groups).

CONCLUSIONS

Simulating apneic oxygenation in a preoxygenated manikin, deep laryngeal oxygen insufflation via the dual-use laryngoscope kept oxygen percentage in the test lung above 90%, and was more effective than oxygen insufflation via nasal prongs.