Airway management in children: ultrasonography assessment of tracheal intubation in real time?

Ultrasound-Guided Selective Bronchial Intubation: A Feasibility Study in Pediatric Animal Model

Objective

Selective one-lung ventilation used to optimize neonatal and pediatric surgical conditions is always a demanding task for anesthesiologists, especially during minimally invasive thoracoscopic surgery. This study aims to introduce an ultrasound-guided bronchial intubation and exclusion technique in a pediatric animal model.

Methods

Seven rabbits were anesthetized and airway ultrasound acquisitions were done.

Results

Tracheal tube progression along the trachea to the right bronchus and positioning of the bronchial blocker in the left bronchus were successfully done with consistent ultrasound identification of relevant anatomical structures.

Conclusion

The study provided a new application of ultrasound in airway management. More advanced experimental studies are needed since this technique has the potential for translation to pediatric anesthesia.

Point-of-care ultrasound to confirm endotracheal tube cuff position in relationship to the cricoid in the pediatric population

BACKGROUND

Anatomically, the subglottic area and the cricoid ring are the narrowest portions of the larynx. To limit the potential for damage related to mucosal pressure injuries from the presence of an endotracheal tube, the cuff should be placed below the cricoid in children. Previously, no clinical or imaging method has been used in real time to determine the exact location of the endotracheal tube cuff after endotracheal intubation. Point-of-care ultrasound may provide an option as a safe and rapid means of visualizing the endotracheal tube cuff and its relationship to the cricoid ring thereby achieving ideal endotracheal tube cuff positioning-below the cricoid.

METHODS

In this prospective, nonrandomized trial, point-of-care ultrasound was used following endotracheal intubation in children to evaluate the position of the endotracheal tube cuff in relationship to the cricoid and tracheal rings. After anesthesia was induced and the trachea was intubated, the endotracheal tube cuff and its position in relation to the cricoid and tracheal rings were identified in the longitudinal plane using point-of-care ultrasound. With the patient's neck in a neutral position, the level of the proximal (cephalad) margin of the saline-filled cuff of the endotracheal tube was identified and recorded in relationship to the cricoid and tracheal rings. The ideal position is defined as the cephalad margin of the endotracheal tube cuff below the level of the cricoid.

RESULTS

The study cohort included 80 patients, ranging in age from 1 to 78 months. In all patients, the cuff of the ETT, cricoid, and tracheal rings were identified. The cephalad end of the endotracheal tube cuff was found at the level of the cricoid in 16.3% of patients, at the first tracheal ring in 27.5% of patients, at the second tracheal ring in 23.8% of patients, at the third tracheal ring in 17.5% of patients, and at below the fourth tracheal ring in 15% of patients. Initial endotracheal tube cuff position had no significant association with age, height, weight, endotracheal tube size, and endotracheal tube type.

CONCLUSION

Point-of-care ultrasound provides a rapid and effective means of identifying the position of the endotracheal tube cuff in relationship to the cricoid ring. The technique may have applications in the perioperative arena, emergency departments, and intensive care units.

The Role of Lung Ultrasound in the Management of the Critically Ill Neonate-A Narrative Review and Practical Guide

Lung ultrasound makes use of artifacts generated by the ratio of air and fluid in the lung. Recently, an enormous increase of research regarding lung ultrasound emerged, especially in intensive care units. The use of lung ultrasound on the neonatal intensive care unit enables the clinician to gain knowledge about the respiratory condition of the patients, make quick decisions, and reduces exposure to ionizing radiation. In this narrative review, the possibilities of lung ultrasound for the stabilization and resuscitation of the neonate using the ABCDE algorithm will be discussed.

Ultrasonography for airway management

Ultrasonography (USG) allows a new approach to the airway in anaesthesia and intensive care. USG visualises the airway from the mouth to the lungs. By exploring the entire airway, USG proposes new criteria (1) to assess the risk of difficult laryngoscopy, (2) to anticipate the management of a difficult airway, (3) to confirm the position of the endotracheal tube (ETT), and (4) to confirm that the lungs are effectively ventilated. Intraoperatively, USG may also help to resolve acute ventilatory problems such as pneumothorax, delayed selective bronchial intubation after patient positioning (Trendelenburg, prone or lateral position) or acute pulmonary oedema.

American Society of Regional Anesthesia and Pain Medicine expert panel recommendations on point-of-care ultrasound education and training for regional anesthesiologists and pain physicians-part I: clinical indications

Point-of-care ultrasound (POCUS) is a critical skill for all regional anesthesiologists and pain physicians to help diagnose relevant complications related to routine practice and guide perioperative management. In an effort to inform the regional anesthesia and pain community as well as address a need for structured education and training, the American Society of Regional Anesthesia and Pain Medicine (ASRA) commissioned this narrative review to provide recommendations for POCUS. The guidelines were written by content and educational experts and approved by the Guidelines Committee and the Board of Directors of the ASRA. In part I of this two-part series, clinical indications for POCUS in the perioperative and chronic pain setting are described. The clinical review addresses airway ultrasound, lung ultrasound, gastric ultrasound, the focus assessment with sonography for trauma examination and focused cardiac ultrasound for the regional anesthesiologist and pain physician. It also provides foundational knowledge regarding ultrasound physics, discusses the impact of handheld devices and finally, offers insight into the role of POCUS in the pediatric population.

Point-of-care ultrasound for the pediatric regional anesthesiologist and pain specialist: a technique review

Point-of-care ultrasound (PoCUS) has been well described for adult perioperative patients; however, the literature on children remains limited. Regional anesthesiologists have gained interest in expanding their clinical repertoire of PoCUS from regional anesthesia to increasing numbers of applications. This manuscript reviews and highlights emerging PoCUS applications that may improve the quality and safety of pediatric care.

In infants and children, lung and airway PoCUS can be used to identify esophageal intubation, size airway devices such as endotracheal tubes, and rule in or out a pulmonary etiology for clinical decompensation. Gastric ultrasound can be used to stratify aspiration risk when nil-per-os compliance and gastric emptying are uncertain. Cardiac PoCUS imaging is useful to triage causes of undifferentiated hypotension or tachycardia and to determine reversible causes of cardiac arrest. Cardiac PoCUS can assess for pericardial effusion, gross ventricular systolic function, cardiac volume and filling, and gross valvular pathology. When PoCUS is used, a more rapid institution of problem-specific therapy with improved patient outcomes is demonstrated in the pediatric emergency medicine and critical care literature.

Overall, PoCUS saves time, expedites the differential diagnosis, and helps direct therapy when used in infants and children. PoCUS is low risk and should be readily accessible to pediatric anesthesiologists in the operating room.

Endotracheal Tube Placement Confirmation with Bedside Ultrasonography in the Pediatric Intensive Care Unit: A Validation Study

Critically ill patients who are intubated undergo multiple chest X-rays (CXRs) to determine endotracheal tube position; however, other modalities can save time, medical expenses, and radiation exposure. In this article, we evaluated the validity and interrater reliability of ultrasound to confirm endotracheal tube (ETT) position in patients. A prospective study was performed on intubated patients with cuffed ETTs. The accuracy of ultrasound to confirm correct ETT placement in 92 patients was 97.8%. Sensitivity, positive predictive value, and agreement of 97.7, 93.3, and 91.3% were found on comparing ultrasound to CXR findings. Ultrasound is feasible, reliable, and has good interrater reliability in assessing correct ETT position in children.

Ultrasound guided tracheal intubation with a styleted tracheal tube in anticipated difficult airway

Ultrasonography is a simple, reliable, non-invasive technique which helps in real-time assessment of airway anatomy and contributes to safer airway management in various settings like operating rooms, intensive care units and emergency departments. It also helps us to plan the appropriate anesthetic technique especially in difficult airway cases. Here, we discuss the importance of styleted tracheal tube in improving the accuracy of ultrasound guided tracheal intubation in anticipated difficult airway.

Learning curve of ultrasound measurement of subglottic diameter for endotracheal tube selection in pediatric patients

BACKGROUND

Endotracheal tube size can be predicted according to ultrasound measurement of subglottic airway diameter. The learning curve for this method is not yet established. The aim was to evaluate the learning curve of anesthesiology residents in ultrasound measurement of subglottic airway diameter for prediction of endotracheal tube size using cumulative sum analysis.

METHODS

Sixteen anesthesiology residents measured transverse subglottic airway diameter in children undergoing general anesthesia with cuffed endotracheal intubation. Each resident performed 30 ultrasound examinations. Primary outcome was the successful prediction of endotracheal tube size according to ultrasound measurement. Cumulative sum analysis was performed with acceptable and unacceptable failure rates set as 20 and 40%, respectively.

RESULTS

Ten out of 16 residents (62.5%) were deemed successful as they were able to pass lower decision boundary, whereas six residents' CUSUM scores were between the decisions lines deeming them indeterminate. The overall success rate for determining the correct endotracheal tube size was 77.5%. Median number of attempts to cross lower decision boundary was 29 with minimum of 18 and maximum of 29 attempts among successful residents.

CONCLUSION

Learning curves constructed with cumulative sum analysis in this study showed that only 62.5% of residents were able to correctly predict cuffed endotracheal tube size with 80% success rate. Considerable variability in achieving competency necessitates objective follow-up of individual improvement.

Sonographic Assessment of Oropharynx Movement During Deep Breathing

To investigate the feasibility of ultrasonography in detecting the oropharynx movement during deep breathing and to quantitatively analyze oropharynx airway lumen changes during deep breathing. The motions of oropharynx were monitored, and sonographic measurements of airway lumen were obtained during deep breathing in 448 healthy volunteers. Adequate visualization of oropharynx movement was obtained on all healthy volunteers. The anterior-posterior (AP) diameters and AP/transverse (T) diameter ratios were greater at the end of deep inspiration than that at the end of deep expiration for each sex (p < 0.01). The anterior-posterior dimensional changes were greater than lateral airway dimensional changes each sex (p < 0.05). Ultrasonography could provide realistic impression of the process on the oropharynx movement during deep breathing and perform the quantitative analysis of the oropharynx airway lumen changes during deep breathing. The results were encouraging and supported the utility of ultrasonography in future studies.

Seeing Is Believing: Ultrasound in Pediatric Procedural Performance

Point-of-care ultrasound is currently widely used across the landscape of pediatric care. Ultrasound machines are now smaller, are easier to use, and have much improved image quality. They have become common in emergency departments, ICUs, inpatient wards, and outpatient clinics. Recent growth of supportive evidence makes a strong case for using point-of-care ultrasound for pediatric interventions such as vascular access (in particular, central-line placement), lumbar puncture, fluid drainage (paracentesis, thoracentesis, pericardiocentesis), suprapubic aspiration, and soft tissue incision and drainage. Our review of this evidence reveals that point-of-care ultrasound has become a powerful tool for improving procedural success and patient safety. Pediatric patients and clinicians performing procedures stand to benefit greatly from point-of-care ultrasound, because seeing is believing.

Diagnostic Accuracy of a 3-Point Ultrasound Protocol to Detect Esophageal or Endobronchial Mainstem Intubation in a Pediatric Emergency Department

OBJECTIVES

The aim of this study was to evaluate the diagnostic accuracy of the 3-point approach with ultrasonography for confirming endotracheal tube (ETT) placement in pediatric patients.

METHODS

This was a prospective study conducted at a tertiary care center in Japan between March 2014 and March 2016. Children aged 0 to 18 years requiring endotracheal intubation in our emergency department (ED) who underwent ultrasonography for confirming ETT placement were enrolled. Patients who had already undergone a tracheotomy or intubation before arrival at our ED or who had severe neck injuries hindering ultrasonography were excluded. Quantitative capnography and portable chest x-ray imaging were used as the reference standard for the confirmation of proper ETT placement. The main outcome was the diagnostic accuracy of the 3-point approach with ultrasonography for detecting inappropriate ETT placement.

RESULTS

In total, 68 patients were enrolled. The median age was 17 months (interquartile range, 8-40), and 51.4% were males. Three (4.4%) and 7 (10.3%) patients had esophageal and endobronchial mainstem intubation, respectively. The patients received emergency intubation due to a dysfunction of the central nervous system (45.6%) or respiratory failure (22.0%). The sensitivity and specificity of esophageal versus tracheal intubation was 100% (95% confidence interval [CI], 54.9%-100.0%) and 100% (95% CI, 97.9%-100.0%), respectively, whereas for endobronchial mainstem intubation versus tracheal intubation, the sensitivity and specificity was 85.7% (95% CI, 56.7%-96.0%) and 98.3% (95% CI, 94.8%-99.5%), respectively. Agreement between the reviewers was high (kappa coefficient, 0.78).

CONCLUSION

The 3-point approach with ultrasonography was a feasible method for detecting esophageal and endobronchial mainstem intubation in pediatric patients.

Confirmation of placement of endotracheal tube - A comparative observational pilot study of three ultrasound methods

Background and Aims

Confirmation of endotracheal tube (ETT) position is necessary to ensure proper ventilation. The present study was conducted with the aim to compare the efficacy of three ultrasonographic (USG) techniques in terms of time taken for confirmation of ETT position. The time taken by each USG technique was also compared with that for auscultation and capnography. The ability of the three USG techniques to identify tracheal placement of ETT was evaluated in all patients.

Material and Methods

Ninety adult American Society of Anesthesiologists (ASA) I/II patients requiring general anaesthesia with tracheal intubation were randomised into three groups (n = 30 each) depending upon the initial USG transducer position used to confirm tracheal placement of ETT: group T (tracheal), group P (pleural) and group D (diaphragm). The time taken for confirmation of tracheal placement of ETT by USG, auscultation and capnography was recorded for each of the groups. Subsequently, USG confirmation of ETT placement was performed with the other two USG techniques in all patients.

Results

The time taken for USG in group T was significantly less (3.8 ± 0.9 s) compared to group P (12.1 ± 1.6 s) and group D (13.8 ± 1.7 s); P < 0.001. USG was significantly faster than both auscultation and capnography in group T (P < 0.001), whereas in group P and group D, USG took longer time compared to auscultation (P = 0.014 and P < 0.001, respectively) but lesser time than capnography (P < 0.001 in both groups).

Conclusion

USG is a rapid technique for identification of ETT placement. All the three USG techniques are reliable in identifying the tracheal placement of ETT.

Avoid the Goose! Paramedic Identification of Esophageal Intubation by Ultrasound

OBJECTIVES

Rapid identification of esophageal intubations is critical to avoid patient morbidity and mortality. Continuous waveform capnography remains the gold standard for endotracheal tube (ETT) confirmation, but it has limitations. Point-of-care ultrasound (POCUS) may be a useful alternative for confirming ETT placement. The objective of this study was to determine the accuracy of paramedic-performed POCUS identification of esophageal intubations with and without ETT manipulation.

METHODS

A prospective, observational study using a cadaver model was conducted. Local paramedics were recruited as subjects and each completed a survey of their demographics, employment history, intubation experience, and prior POCUS training. Subjects participated in a didactic session in which they learned POCUS identification of ETT location. During each study session, investigators randomly placed an ETT in either the trachea or esophagus of four cadavers, confirmed with direct laryngoscopy. Subjects then attempted to determine position using POCUS both without and with manipulation of the ETT. Manipulation of the tube was performed by twisting the tube. Descriptive statistics and logistic regression were used to assess the results and the effects of previous paramedic experience.

RESULTS

During 12 study sessions, from March 2014 through December 2015, 57 subjects participated, evaluating a total of 228 intubations: 113 tracheal and 115 esophageal. Subjects were 84.0% male, mean age of 39 years (range: 22 - 62 years), with median experience of seven years (range: 0.6 - 39 years). Paramedics correctly identified ETT location in 158 (69.3%) cases without and 194 (85.1%) with ETT manipulation. The sensitivity and specificity of identifying esophageal location without ETT manipulation increased from 52.2% (95% confidence interval [CI], 43.0-61.0) and 86.7% (95% CI, 81.0-93.0) to 87.0% (95% CI, 81.0-93.0) and 83.2% (95% CI, 0.76-0.90) after manipulation (P<.0001), without affecting specificity (P=.45). Subjects correctly identified 41 previously incorrectly identified esophageal intubations. Paramedic experience, previous intubations, and POCUS experience did not correlate with ability to identify tube location.

CONCLUSION

Paramedics can accurately identify esophageal intubations with POCUS, and manipulation improves identification. Further studies of paramedic use of dynamic POCUS to identify inadvertent esophageal intubations are needed. LemaPC, O'BrienM, WilsonJ, St. JamesE, LindstromH, DeAngelisJ, CaldwellJ, MayP, ClemencyB. Avoid the goose! Paramedic identification of esophageal intubation by ultrasound. Prehosp Disaster Med. 2018;33(4):406-410.

Ultrasound measurement of anatomical parameters of the upper airway in adults

BACKGROUND

Most of the works on ultrasound airway anatomy are limited to a morphological description. A study was conducted in order to provide an objective normal range of measurements.

MATERIALS AND METHODS

Observational study to describe the ultrasound characteristics of the upper airway in adults without clinical difficult airway criteria, compared to cadaver dissection anatomical models.

RESULTS

The study included 45 volunteers (27 men and 18 women), and 3fresh cadavers. The quality of the examination was very good/good in 93% of the cases.

MEASUREMENTS

tracheal diameter (1.3±0.3cm), vocal cord (1.6±0.5cm), cricothyroid membrane (0.94±0.32cm), cricotracheal membrane (0.3±0.09cm), thickness of the muscles in the floor of the mouth (MFM) (1.5±0.26cm), sub-mandibular subcutaneous fat plus MFM (2.11±0.34cm), hyoid-mandible distance (5.35±0.69cm), palate-floor of the mouth distance (4.92±0.5cm), palate-anterior border of the mandible (5.51±0.7cm), and palate-pharynx angle (114±14). Observed differences: Males had a larger tracheal diameter than females (M: 1.4±0.3 vs. F: 1.2±0.2cm, p=0.014). Subject height showed a significant correlation with the tracheal diameter (R: 0.501, p<0.001), as well as the length of the vocal cord (R: 0.363, p=0.016), the thickness of MFM (R=0.299, p=0.046) as well as the hyoid-mandible (R: 0.556; p<0.001) and palate-mandible distances (R: 0.362; p=0.015).

CONCLUSIONS

Ultrasound allows the anatomy of upper airway to be evaluated, as well as to calculate distances between the anatomical structures. The study defines these distances in adult volunteers without clinical difficult airway criteria.

[Ultrasound guided airway access]

Ultrasound has increasingly growing applications in anesthesia. This procedure has proven to be a novel, non-invasive and simple technique for the upper airway management, proving to be a useful tool, not only in the operating room but also in the intensive care unit and emergency department. Indeed, over the years mounting evidence has showed an increasing role of ultrasound in airway management. In this review, the authors will discuss the importance of ultrasound in the airway preoperative assessment as a way of detecting signs of difficult intubation or to define the type and/or size of the endotracheal tube as well as to help airway procedures such as endotracheal intubation, cricothyrotomy, percutaneous tracheal intubation, retrograde intubation as well as the criteria for extubation.

Integration of Point-of-care Ultrasound during Rapid Sequence Intubation in Trauma Resuscitation

Introduction:

Airway and breathing management play critical role in trauma resuscitation. Early identification of esophageal intubation and detection of fatal events is critical. Authors studied the utility of integration of point-of-care ultrasound (POCUS) during different phases of rapid sequence intubation (RSI) in trauma resuscitation.

Methods:

It was prospective, randomized single-centered study conducted at the Emergency Department of a level one trauma center. Patients were divided into ultrasonography (USG) and clinical examination (CE) arm. The objectives were to study the utility of POCUS in endotracheal tube placement and confirmations and identification of potentially fatal conditions as tracheal injury, midline vessels, paratracheal hematoma, vocal cord pathology, pneumothorax, and others during RSI. Patient >1 year of age were included. Time taken for procedure, number of incorrect intubations, and pathologies detected were noted. The data were collected in Microsoft Excel spread sheets and analyzed using Stata (version 11.2, Stata Corp, Texas, U. S. A) software.

Results:

One hundred and six patients were recruited. The mean time for primary survey USG versus CE arm was (20 ± 10.01 vs. 18 ± 11.03) seconds. USG detected four pneumothorax, one tracheal injury, and one paratracheal hematoma. The mean procedure time USG versus CE arm was (37.3 ± 21.92 vs. 58 ± 32.04) seconds. Eight esophageal intubations were identified in USG arm by POCUS and two in CE arm by EtCO2 values.

Conclusion:

Integration of POCUS was useful in all three phases of RSI. It identified paratracheal hematoma, tracheal injury, and pneumothorax. It also identified esophageal intubation and confirmed main stem tracheal intubation in less time compared to five-point auscultation and capnography.

Predictive Value of Tracheal Rapid Ultrasound Exam Performed in the Emergency Department for Verification of Tracheal Intubation

BACKGROUND

Verification of the correct placement of the endotracheal tube (ETT) has been one of the most challenging issues of airway management in the field of emergency medicine. Early detection of oesophagal intubation through a reliable method is important for emergency physicians.

AIM

The aim of this study was to assess the diagnostic accuracy of tracheal rapid ultrasound exam (TRUE) to assess endotracheal tube misplacement during emergency intubation.

METHODS

This was an observational prospective study performed in the emergency department of the major tertiary referral hospital in the city. We included a consecutive selection of 100 patients. TRUE was performed for all these patients, and subsequently, quantitative waveform capnography was done. The later test is considered as the gold standard.

RESULTS

From our total 100 eligible patients, 93 (93%) participants had positive TRUE results (tracheal intubation) and 7 (7%) patients have negative TRUE results (esophageal intubation). Quantitative waveform capnography report of all 93 (100%) patients who had positive TRUE was positive (appropriate tracheal placement). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of TRUE for detecting appropriate tracheal placement of ETT were 98.9% (95% CI, 93.3% to 99.8%), 100% (95% CI, 51.6% to 100%), 100% (95% CI, 95.1% to 100%) and 85.7% (95% CI, 42% to 99.2%) respectively.

CONCLUSIONS

Performing TRUE is convenient and feasible in many emergency departments and pre-hospital settings. We would recommend emergency units explore the possibility of using TRUE as a method in the assessment of proper ETT placement.

Ultrasonography for endotracheal tube position in infants and children

Ultrasonography (US) has been shown to be effective for verifying endotracheal tube (ETT) position in adults but has been less studied in infants and children. We review the literature regarding US for ETT positioning in the pediatric population. A literature search was conducted using the Ovid and MEDLINE databases with search terms regarding US relating to ETT intubation and positioning in infants and children. Most studies in neonates and infants used the midsagittal suprasternal view. Studies reported >80% visualization of the ETT tip by US, and US interpretation of the ETT position correlated with the XR position in 73-100% of cases. Studies of older children used the suprasternal views, substernal views, and mid-axillary intercostal views. US appears comparable to XR and capnography in determining ETT position in this population.

CONCLUSION

US for ETT verification appears to be well tolerated in infants and children and may augment determination of proper ETT position in combination with other ETT verification modalities. Further studies are needed regarding technique and training. What is Known: • Point-of-care ultrasonography is realizing increased availability and use in several pediatric specialties. • Ultrasonography has been shown to be effective for verifying ETT position in adults but have been less studied in infants and children. What is New: • Ultrasonography for endotracheal tube verification appears to be well tolerated in infants and children. • Ultrasonography may augment determination of proper endotracheal tube position in combination with other verification modalities such as radiography and capnography in the pediatric population.

Design and application of model for training ultrasound-guided vascular cannulation in pediatric patients

Central vascular cannulation is not a risk-free procedure, especially in pediatric patients. Newborn and infants are small and low-weighted, their vascular structures have high mobility because of tissue laxity and their vessels are superficial and with small diameter. These characteristics, together with the natural anatomical variability and poor collaboration of small children, make this technique more difficult to apply. Therefore, ultrasound imaging is increasingly being used to locate vessels and guide vascular access in this population.

OBJECTIVE

(a) To present a model that simulates the vascular system for training ultrasound-guided vascular access in pediatrics patients; (b) to ultrasound-guided vascular cannulation in the model.

RESULTS

The model consisted of two components: (a) muscular component: avian muscle, (b) vascular component: elastic tube-like structure filled with fluid. 864 ecoguided punctures was realized in the model at different vessel depth and gauge measures were simulated, for two medical operators with different degree of experience. The average depth and diameter of vessel cannulated were 1.16 (0.42)cm and 0.43 (0.1)cm, respectively. The average number of attempts was of 1.22 (0.62). The percentage of visualization of the needle was 74%. The most frequent maneuver used for the correct location, was the modification of the angle of the needle and the relocation of the guidewire in 24% of the cases. The average time for the correct cannulations was 41 (35.8)s. The more frequent complications were the vascular perforation (11.9%) and the correct vascular puncture without possibility of introducing the guidewire (1.2%). The rate of success was 96%.

CONCLUSIONS

The model simulates the anatomy (vascular and muscular structures) of a pediatric patient. It is cheap models, easily reproducible and a useful tool for training in ultrasound-guided puncture and cannulation.

Ultrasound: A promising tool for contemporary airway management

Airway evaluation and its management remains an ever emerging clinical science. Present airway management tools are static and do not provide dynamic airway management option. Visualized procedures like ultrasound (US) provide point of care real time dynamic views of the airway in perioperative, emergency and critical care settings. US can provide dynamic anatomical assessment which is not possible by clinical examination alone. US aids in detecting gastric contents and the nature of gastric contents (clear fluid, thick turbid or solid) as well. US can help in predicting endotracheal tube size by measuring subglottic diameter and diameter of left main stem bronchus. US was found to be a sensitive in detecting rotational malposition of LMA in children. Also, US is the fastest and highly sensitive tool to rule out a suspected intraoperative pneumothorax. In intensive care units, US helps torule out causes of inadequate ventilation, determine the tracheal width and distance from the skin to predict tracheotomy tube size and shape and assist with percutaneous dilatational tracheostomy. US can help in confirming the correct tracheal tube placement by dynamic visualisation of the endotracheal tube insertion, widening of vocal cords (children), and bilateral lung-sliding and diaphragmatic movement. Thus, ultrasonography has brought a paradigm shift in the practise of airway management. With increasing awareness, portability, accessibility and further sophistication in technology, it is likely to find a place in routine airway management. We are not far from the time when all of us will be carrying a pocket US machine like stethoscopes to corroborate our clinical findings at point of care.

Defining the learning curve of point-of-care ultrasound for confirming endotracheal tube placement by emergency physicians

Background

Unrecognized esophageal intubations are associated with significant patient morbidity and mortality. No single confirmatory device has been shown to be 100 % accurate at ruling out esophageal intubations in the emergency department. Recent studies have demonstrated that point-of-care ultrasound (POCUS) may be a useful adjunct for confirming endotracheal tube placement; however, the amount of practice required to become proficient at this technique is unclear. The purpose of this study is to determine the amount of practice required by emergency physicians to become proficient at interpreting ultrasound video clips of esophageal and endotracheal intubations.

Methods

Emergency physicians and emergency medicine residents completed a baseline interpretation test followed by a 10 min online tutorial. They then interpreted POCUS clips of esophageal and endotracheal intubations in a randomly selected order. If an incorrect response was provided, the participant completed another practice session with feedback. This process continued until they correctly interpreted ten consecutive ultrasound clips. Descriptive statistics were used to summarize the data.

Results

Of the 87 eligible physicians, 66 (75.9 %) completed the study. The mean score on the baseline test was 42.9 % (SD 32.7 %). After the tutorial, 90.9 % (60/66) of the participants achieved proficiency after one practice attempt and 100 % achieved proficiency after two practice attempts. Six intubation ultrasound clips were misinterpreted, for a total error rate of 0.9 % (6/684). Overall, the participants had a sensitivity of 98.3 % (95 % CI 96.3–99.4 %) and specificity of 100 % (95 % CI 98.9–100 %) for detecting correct tube location. Scans were interpreted within an average of 4 s (SD 2.9 s) of the intubation.

Conclusions

After a brief online tutorial and only two practice attempts, emergency physicians were able to quickly and accurately interpret ultrasound intubation clips of esophageal and endotracheal intubations.

Electronic supplementary material

The online version of this article (doi:10.1186/s13089-015-0031-7) contains supplementary material, which is available to authorized users.

Ultrasonography for confirmation of endotracheal tube placement: a systematic review and meta-analysis

OBJECTIVE

This study aimed to undertake a systematic review and meta-analysis to summarize evidence on the diagnostic value of ultrasonography for the assessment of endotracheal tube placement in adult patients.

METHODS

The major databases, PubMed, EMBASE, and the Cochrane Library, were searched for studies published from inception to June 2014. We selected studies that used ultrasonography to confirm endotracheal tube placement. The search was limited to human studies, and had no publication date or country restrictions. Exclusion criteria included case reports, comments, reviews, guidelines and animal studies. Two reviewers extracted and verified the data independently. We summarized test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random effect models. Meta-regression analysis was performed to explore the source of heterogeneity. The methodological quality of individual studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool.

RESULTS

A total of 12 eligible studies involving adult patients and cadaveric models were identified from 1488 references. For detection of esophageal intubation, the pooled sensitivity was 0.93 (95% CI: 0.86-0.96) and the specificity was 0.97 (95% CI: 0.95-0.98). The area under the summary ROC curve was 0.97 (95% CI: 0.95-0.98). The positive and negative likelihood ratios were 26.98 (95% CI: 19.32-37.66) and 0.08 (95% CI: 0.04-0.15), respectively.

CONCLUSIONS

Current evidence supports that ultrasonography has high diagnostic value for identifying esophageal intubation. With optimal sensitivity and specificity, ultrasonography can be a valuable adjunct in this aspect of airway assessment, especially in situations where capnography may be unreliable.

Three-finger tracheal palpation to guide endotracheal tube depth in children

BACKGROUND

Accurate endotracheal tube (ETT) depth is critical, especially in children. The current tools used to guide appropriate ETT depth have significant limitations.

OBJECTIVES

To evaluate the utility of tracheal palpation in the neck to guide appropriate ETT placement in children.

METHODS

A prospective observational study with a convenience sample of 50 children was conducted. During intubation, an investigator palpated the trachea with three fingertips side-by-side extending upward from the suprasternal notch. The anesthesiologist advanced the ETT slowly until palpated at the sternal notch. The investigator stated ETT palpation certainty as 'strongly felt', 'weakly felt', or 'not felt.' Final ETT position was determined by bronchoscopy and categorized as 'ETT too shallow' (tip in proximal ¼ of trachea), 'ETT too deep' (tip in distal ¼ of trachea), or 'ETT placement satisfactory' (between those extremes).

RESULTS

Thirty boys and 20 girls undergoing dental surgery with nasal intubation were recruited (median age 4.4 years; range 2.0-10.8). The ETT (all ≥4 mm ID) was palpable at the sternal notch in all patients: 46 of 50 strongly palpable and 4 of 50 weakly palpable. The experimental methods led to satisfactory ETT placement in 49 of 50 patients, too deep in 1 of 50 patients. Compared with the Pediatrics Advanced Life Support (PALS) predictive formula, satisfactory placement would have been 41 of 50 patients (P < 0.008). Number needed to treat is 6.3 for improvement over the PALS method.

CONCLUSIONS

The use of tracheal palpation to guide ETT placement has excellent clinical performance and better guides appropriate ETT depth than the PALS formula in our study population.

Ultrasound: A novel tool for airway imaging

Context:

The scope of ultrasound is emerging in medical science, particularly outside traditional areas of radiology practice.

Aims:

We designed this study to evaluate feasibility of bedside sonography as a tool for airway assessment and to describe sonographic anatomy of airway.

Settings and Design:

A prospective, clinical study.

Materials and Methods:

We included 100 adult, healthy volunteers of either sex to undergo airway imaging systemically starting from floor of the mouth to the sternal notch in anterior aspect of neck by sonography.

Results:

We could visualize mandible and hyoid bone as a bright hyperechoic structure with hypoechoic acoustic shadow underneath. Epiglottis, thyroid cartilage, cricoid cartilage, and tracheal rings appeared hypoechoic. Vocal cords were visualized through thyroid cartilage. Interface between air and mucosa lining the airway produced a bright hyperechoic linear appearance. Artifacts created by intraluminal air prevented visualization of posterior pharynx, posterior commissure, and posterior wall of trachea.

Conclusions:

Ultrasound is safe, quick, noninvasive, repeatable, and bedside tool to assess the airway and can provide real-time dynamic images relevant for several aspects of airway management.

Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae

OBJECTIVES

To create a state-of-the-art overview of the new and expanding role of ultrasonography in clinical decision-making, intervention and management of the upper and lower airways, that is clinically relevant, up-to-date and practically useful for clinicians.

METHODS

This is a narrative review combined with a structured Medline literature search.

RESULTS

Ultrasonography can be utilised to predict airway difficulty during induction of anaesthesia, evaluate if the stomach is empty or possesses gastric content that poses an aspiration risk, localise the essential cricothyroid membrane prior to difficult airway management, perform nerve blocks for awake intubation, confirm tracheal or oesophageal intubation and facilitate localisation of tracheal rings for tracheostomy. Ultrasonography is an excellent diagnostic tool in intraoperative and emergency diagnosis of pneumothorax. It also enables diagnosis and treatment of interstitial syndrome, lung consolidation, atelectasis, pleural effusion and differentiates causes of acute breathlessness during pregnancy. Patient safety can be enhanced by performing procedures under ultrasound guidance, e.g. thoracocentesis, vascular line access and help guide timing of removal of chest tubes by quantification of residual pneumothorax size.

CONCLUSIONS

Ultrasonography used in conjunction with hands-on management of the upper and lower airways has multiple advantages. There is a rapidly growing body of evidence showing its benefits.

TEACHING POINTS

• Ultrasonography is becoming essential in management of the upper and lower airways. • The tracheal structures can be identified by ultrasonography, even when unidentifiable by palpation. • Ultrasonography is the primary diagnostic approach in suspicion of intraoperative pneumothorax. • Point-of-care ultrasonography of the airways has a steep learning curve. • Lung ultrasonography allows treatment of interstitial syndrome, consolidation, atelectasis and effusion.

Ultrasound for the anesthesiologists: present and future

Ultrasound is a safe, portable, relatively inexpensive, and easily accessible imaging modality, making it a useful diagnostic and monitoring tool in medicine. Anesthesiologists encounter a variety of emergent situations and may benefit from the application of such a rapid and accurate diagnostic tool in their routine practice. This paper reviews current and potential applications of ultrasound in anesthesiology in order to encourage anesthesiologists to learn and use this useful tool as an adjunct to physical examination. Ultrasound-guided peripheral nerve blockade and vascular access represent the most popular ultrasound applications in anesthesiology. Ultrasound has recently started to substitute for CT scans and fluoroscopy in many pain treatment procedures. Although the application of airway ultrasound is still limited, it has a promising future. Lung ultrasound is a well-established field in point-of-care medicine, and it could have a great impact if utilized in our ORs, as it may help in rapid and accurate diagnosis in many emergent situations. Optic nerve sheath diameter (ONSD) measurement and transcranial color coded duplex (TCCD) are relatively new neuroimaging modalities, which assess intracranial pressure and cerebral blood flow. Gastric ultrasound can be used for assessment of gastric content and diagnosis of full stomach. Focused transthoracic (TTE) and transesophageal (TEE) echocardiography facilitate the assessment of left and right ventricular function, cardiac valve abnormalities, and volume status as well as guiding cardiac resuscitation. Thus, there are multiple potential areas where ultrasound can play a significant role in guiding otherwise blind and invasive interventions, diagnosing critical conditions, and assessing for possible anatomic variations that may lead to plan modification. We suggest that ultrasound training should be part of any anesthesiology training program curriculum.

Electrical impedance tomography for verification of correct endotracheal tube placement in paediatric patients: a feasibility study

BACKGROUND

Endotracheal tubes (ETTs) are frequently used in paediatric anaesthesia. Correct placement is crucial. The aim of this study was to evaluate electrical impedance tomography (EIT) for guiding and confirmation of paediatric ETT placement. In a retrospective analysis of stored EIT data, distribution of ventilation between left and right lung was used to verify correct paediatric ETT placement.

METHODS

Left and right lung ventilation was studied by EIT in 18 paediatric patients (median age: 53 months) requiring anaesthesia and endotracheal intubation. EIT was recorded before induction of anaesthesia, during mask ventilation, during ETT placement (including deliberate mainstem intubation), and after ETT repositioning according to the formula: ETT intubation depth (cm) = 3× ETT internal diameter (mm) or the mainstem intubation method (withdrawing the ETT 2 cm). Final ETT position was confirmed by fluoroscopy.

RESULTS

Following deliberate mainstem intubation, distribution of ventilation to the right lung was unequivocally demonstrated by EIT. Homogeneous distribution of ventilation between left and right lung monitored with EIT correlated in each patient with correct endotracheal ETT placement. The distribution of left and right lung ventilation differed significantly (P < 0.05) between the initial two-lung ventilation and subsequent right one-lung ventilation, and between right one-lung and subsequent two-lung ventilation according to auscultation and the final ETT position, respectively. In one patient, ETT was misplaced within the oesophagus which was also obvious from the EIT record.

CONCLUSION

This study demonstrates that EIT enables non-invasive recognition of correct ETT placement. Homogeneous right-left-lung ventilation is an indicator for correct ETT placement.

Ingested foreign bodies: a case series demonstrating a novel application of point-of-care ultrasonography in children

In an era of recognizing the risks of radiation exposure, it is important to develop alternatives to radiographs. Bedside ultrasound has become an important adjunct to clinical diagnoses and procedural guidance in the emergency department. We present a case series of two patients who presented to a pediatric emergency department after witnessed coin ingestions. Point-of-care ultrasonography was able to accurately identify the location of each of the coins, at the thoracic inlet and in the stomach, as confirmed by chest radiography. To our knowledge, point-of-care ultrasonography has not been previously utilized to detect and localize esophageal foreign bodies in the emergency department.

Ultrasound of the airway

Currently, the role of ultrasound (US) in anaesthesia-related airway assessment and procedural interventions is encouraging, though it is still ill defined. US can visualise anatomical structures in the supraglottic, glottic and subglottic regions. The floor of the mouth can be visualised by both transcutaneous view of the neck and also by transoral or sublinguial views. However, imaging the epiglottis can be challenging as it is suspended in air. US may detect signs suggestive of difficult intubation, but the data are limited. Other possible applications in airway management include confirmation of correct endotracheal tube placement, prediction of post-extubation stridor, evaluation of soft tissue masses in the neck prior to intubation, assessment of subglottic diameter for determination of paediatric endotracheal tube size and percutaneous dilatational tracheostomy. With development of better probes, high-resolution imaging, real-time picture and clinical experience, US has become the potential first-line noninvasive airway assessment tool in anaesthesia and intensive care practice.