Auscultation versus Point-of-care Ultrasound to Determine Endotracheal versus Bronchial Intubation

Perioperative Point-of-Care Ultrasound

This clinical focus review targets all anesthesiologists and seeks to highlight the following aspects of perioperative point-of-care ultrasound: clinical utility, technology advancements, training/certification, education, reporting/billing, and limitations.

Tracheal Ultrasound for the Accurate Confirmation of the Endotracheal Tube Position in Obese Patients

OBJECTIVES

Obesity is a serious disorder that may lead to numerous difficulties in endotracheal tube (ETT) management. This study investigated the potential of tracheal ultrasound (TUS) for the accurate confirmation of the ETT position in obese patients.

METHODS

A total of 68 obese patients undergoing tracheal intubation were enrolled in this study from January 2017 to June 2018. All patients received auscultation and TUS to evaluate the ETT position, which was ultimately verified by bronchoscopy. A correct position of the ETT was defined as placement at the trachea, whereas placement at the right/left main bronchus was classified as an incorrect position.

RESULTS

We found 58 correct placements of the ETT at the trachea, 8 incorrect placements at the right main bronchus, and 2 incorrect placements at the left main bronchus. Compared with auscultation, TUS showed higher accuracy (85.29% versus 67.65%; P = .005), sensitivity (84.48% versus 67.24%; P = .005), and specificity (90.00% versus 70.00%; P < .001), as well as lower rates of false-positive (10.00% versus 30.00%; P < .001) and false-negative (15.52% versus 32.76%; P = .005) results for detecting the correct placement of the ETT, defined as placement at the trachea.

CONCLUSIONS

Tracheal ultrasound is highly sensitive and specific in confirming the ETT position in obese patients.

Basic point-of-care ultrasound framework based on the airway, breathing, and circulation approach for the initial management of shock and dyspnea

Ultrasound (US) carried out and interpreted by clinicians at the bedside is now called point‐of‐care US (POCUS). Clinical studies on POCUS have been carried out based on the ideas of “creation”, “extraction”, and “combination”. “Creation” refers to findings for the upper airway and lung being obtained at the bedside. “Extraction” refers to findings suitable for POCUS being extracted from comprehensive US, including echocardiography, abdominal US, and whole‐leg US. “Combination” refers to these POCUS applications being combined for the comprehensive assessment of patients with trauma, shock, or dyspnea. Emergency and critical care physicians have many opportunities to encounter trauma or non‐trauma patients with shock, dyspnea, or both. Furthermore, the scope of POCUS includes many diseases and injuries that present with both shock and dyspnea. Therefore, we propose a basic POCUS framework based on the systematic airway, breathing, and circulation approach for the initial management of shock and dyspnea in adult patients. In this article, we update and review each application of POCUS and their combination in this framework. Furthermore, we propose the practical usage of the framework based on clinical presentations to improve the management of shock and dyspnea.

A Formula for Estimating the Appropriate Tube Depth for Intubation

An estimation of the appropriate tubing depth for fixation is helpful to prevent inadvertent endobronchial intubation and prolapse of cuff from the vocal cord. A feasible estimation formula should be established. We measured the anatomical length of the upper-airway tract through the oral and nasal pathways on cephalometric radiographs and tried to establish the estimation formula from the height of the patient. The oral upper-airway tract was measured from the tip of the incisor to the vocal cord. The nasal upper-airway tract was measured from the tip of the nostril to the vocal cord. The tracts were smoothly traced by using software. The length of the oral upper-airway tract was 13.2 ± 0.8 cm, and the nasal upper-airway tract was 16.1 ± 0.9 cm. We found no gender difference ( p > .05). The correlations between the patients' height and the length of the oral and nasal upper-airway tracts were 0.692 and 0.760, respectively. We found that the formulas (height/10) - 3 (in cm) for oral upper-airway and (height/10) + 1 (in cm) for nasal upper-airway tract are the simple fit estimation formulas. The average error and standard deviation of the estimated values from the measured values were 0.50 ± 0.66 cm for the oral tract and 0.39 ± 0.63 cm for the nasal tract. Thus, considering the length of the intubation marker of each product (DM), we would like to propose the length of tube fixation as (height/10) + 1 + DM for nasal intubation and (height/10) - 3 + DM for oral intubation. In conclusion, the estimation formulas of (height/10) - 3 + DM and (height/10) + 1 + DM for oral and nasal intubation, respectively, are within almost 1 cm error in most cases.

Ultrasound for airway management: An evidence-based review for the emergency clinician

BACKGROUND

Airway management is a common procedure performed in the Emergency Department with significant potential for complications. Many of the traditional physical examination maneuvers have limitations in the assessment and management of difficult airways. Point-of-care ultrasound (POCUS) has been increasingly studied for the evaluation and management of the airway in a variety of settings.

OBJECTIVE

This article summarizes the current literature on POCUS for airway assessment, intubation confirmation, endotracheal tube (ETT) depth assessment, and performing cricothyroidotomy with an emphasis on those components most relevant for the Emergency Medicine clinician.

DISCUSSION

POCUS can be a useful tool for identifying difficult airways by measuring the distance from the skin to the thyrohyoid membrane, hyoid bone, or epiglottis. It can also predict ETT size better than age-based formulae. POCUS is highly accurate for confirming ETT placement in adult and pediatric patients. The typical approach involves transtracheal visualization but can also include lung sliding and diaphragmatic elevation. ETT depth can be assessed by visualizing the ETT cuff in the trachea, as well as using lung sliding and the lung pulse sign. Finally, POCUS can identify the cricothyroid membrane more quickly and accurately than the landmark-based approach.

CONCLUSION

Airway management is a core skill in the Emergency Department. POCUS can be a valuable tool with applications ranging from airway assessment to dynamic cricothyroidotomy. This paper summarizes the key literature on POCUS for airway management.

Tracheal, Lung, and Diaphragmatic Applications of M-Mode Ultrasonography in Anesthesiology and Critical Care

Today, proficiency in cardiopulmonary ultrasound is considered essential for anesthesiologists and critical care physicians. Conventional 2-dimensional images, however, do not permit optimal characterization of specific conditions (eg, diaphragmatic paralysis, major atelectasis, and pneumothorax) that may have relevant clinical implications in critical care and perioperative settings. By contrast, M-mode (motion-based) ultrasonographic imaging modality offers the highest temporal resolution in ultrasonography; this modality, therefore, can provide important information in ultrasound-driven approaches performed by anesthesiologists and intensivists for diagnosis, monitoring, and procedural guidance. Despite its practicability, M-mode has been progressively abandoned in echocardiography and is often underused in lung and diaphragmatic ultrasound. This review describes contemporary applications of M-mode ultrasonography in the practice of critical care and perioperative medicine. Information presented for each clinical application includes image acquisition and interpretation, evidence-based clinical implications in critically ill and surgical patients, and main limitations. The article focuses on tracheal, lung, and diaphragmatic ultrasound. It reviews tracheal ultrasound for procedural guidance during endotracheal intubation, confirmation of correct tube placement, and detection of esophageal intubation; lung ultrasound for the confirmation of endotracheal and endobronchial (selective) intubation and for the diagnosis of pneumothorax, alveolar-interstitial syndrome (cardiogenic v noncardiogenic pulmonary edema), pulmonary consolidation (pneumonia v major atelectasis) and pleural effusion; and diaphragmatic ultrasound for the diagnosis of diaphragmatic dysfunction and prediction of extubation success.

Improved diagnostic accuracy of pathology with the implementation of a perioperative point-of-care ultrasound service: quality improvement initiative

Introduction

The utility of perioperative point-of-care ultrasound (P-POCUS) is rapidly growing. The successful implementation of a comprehensive P-POCUS curriculum, Focused PeriOperative Risk Evaluation Sonography Involving Gastro-abdominal, Hemodynamic, and Trans-thoracic Ultrasound (FORESIGHT), has been demonstrated. This project sought to further evaluate the utility of P-POCUS with the following aims: (1) to assess the ability to train the FORESIGHT curriculum via a free, open-access, online platform; (2) to launch a P-POCUS clinical service as a quality improvement (QI) initiative; (3) to evaluate the diagnostic accuracy of the P-POCUS examinations to formal diagnostic studies; and (4) to compare the P-POCUS diagnostic accuracy with the diagnostic accuracy of traditional assessment (TA).

Methods

This study was launched as a QI project for the implementation of a P-POCUS service. A group of attending and resident anesthesiologists completed P-POCUS training supported by an online curriculum. After training, a P-POCUS service was launched. The P-POCUS service was available for any perioperative event, and specific triggers were also identified. All examinations were documented on a validated datasheet. The diagnostic accuracy of the two index tests, P-POCUS and TA, were compared with formal diagnostic testing. TA was defined as a combination of the anesthesiologist’s bedside assessment and physical examination. The primary outcome marker was a comparison in the accuracy of new diagnosis detected by P-POCUS service versus the TA performed by the primary anesthesiologist.

Results

A total of 686 P-POCUS examinations were performed with 466 examinations having formal diagnostic studies for comparison. Of these, 92 examinations were detected as having new diagnoses. Performance for detection of a new diagnosis demonstrated a statistically higher sensitivity for the P-POCUS examinations (p<0.0001). Performance comparison of all P-POCUS examinations that were matched to formal diagnostic studies (n=466) also demonstrated a significantly higher sensitivity. These findings were consistent across cardiovascular, pulmonary and abdominal P-POCUS categories (p<0.01). Additionally, multiple pathologies demonstrated complete agreement between the P-POCUS examination and the formal study.

Conclusion

A P-POCUS service can be developed after training facilitated by an online curriculum. P-POCUS examinations can be performed by anesthesiologists with a high degree of accuracy to formal studies, which is superior to TA.

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.

Cardiac and lung point-of-care ultrasound in pediatric anesthesia and critical care medicine: Uses, pitfalls, and future directions to optimize pediatric care

Point-of-care ultrasound (POCUS) has found many relevant applications in pediatric anesthesia and critical care medicine. Specifically, the cardiac and pulmonary POCUS examinations provide a wealth of information from physical examination assistance to diagnostic evaluation and assessment of treatment response. However, as with any adjunct, potentially dangerous pitfalls exist when POCUS is performed, interpreted, and applied by the novice sonographer. Using case illustrations, we highlight the clinical application of POCUS in addition to potential dangers. Additionally, suggestions for learning POCUS, assessing competency and credentialing are reviewed.

Point-of-care lung ultrasound to evaluate lung isolation during one-lung ventilation in children: A case report

Minimally invasive thoracic surgical techniques require effective lung separation using one-lung ventilation (OLV). Verification of lung isolation may be confirmed by auscultation, visual confirmation using fiberoptic bronchoscopy, or more recently, point-of-care ultrasound (POCUS). We describe anecdotal experience with POCUS to guide OLV during robotic-assisted thoracic surgery in a child. Techniques to confirm thoracic separation are reviewed and potential advantages of POCUS discussed.

Getting to know a familiar face: Current and emerging focused ultrasound applications for the perioperative setting

Ultrasound technology is available in many pediatric perioperative settings. There is an increasing number of ultrasound applications for anesthesiologists which may enhance clinical performance, procedural safety, and patient outcomes. This review highlights the literature and experience supporting focused ultrasound applications in the pediatric perioperative setting across varied disciplines including anesthesiology. The review also suggests strategies for building educational and infrastructural systems to translate this technology into clinical practice.

A controlled trial to investigate whether the orientation of the bevel and angle of approach determine the side of endobronchial intubation in an adult manikin

One of the commonest complications of endotracheal intubation occurs when the tip of the endotracheal tube passes distal to the carina and enters one of the main bronchi. The perioperative practitioner may observe high airway pressures, hypoxia or even pneumothorax. The most common reason given for the high incidence of right endobronchial intubation is that the right main bronchus comes off the trachea at a more acute angle from the midline. We sought, however, to explore two other factors which may explain this phenomenon – the angle of the tube’s bevel and its trajectory of approach. We conducted a prospective controlled trial in which doctors from our department intubated the trachea of an adult manikin in three distinct sets using standard tube, reversed tubes and reversed laryngoscope blades. We found that the angle of the bevel and trajectory of approach determines the side of endobronchial intubation in an adult manikin.

Is prehospital endobronchial intubation a risk factor for subsequent ventilator associated pneumonia? A retrospective analysis

More than half of patients under mechanical ventilation in the intensive care unit (ICU) are field-intubated, which is a known risk factor for ventilator associated pneumonia (VAP). We assessed whether field endobronchial intubation (EBI) is associated with the development of subsequent VAP during the ICU stay. This retrospective, nested case-control study was conducted in a cohort of field-intubated patients admitted to an ICU of a teaching hospital during a three-year period. Cases were defined as field-intubated patients with EBI and controls corresponded to field-intubated patients with proper position of the tracheal tube on admission chest X-ray. Primary endpoint was the development of early VAP. Secondary endpoints included the development of early ventilator associated tracheo-bronchitis, late VAP, duration of mechanical ventilation, length of stay and mortality in the ICU. A total of 145 patients were studied (mean age: 54 ± 19 years; men: 74%). Reasons for field intubation were predominantly multiple trauma (49%) and cardiorespiratory arrest (38%). EBI was identified in 33 patients (23%). Fifty-three patients (37%) developed early or late VAP. EBI after field intubation was associated with a nearly two-fold increase of early VAP, though not statistically significant (30% vs. 17%: p = 0.09). No statistically significant difference was found regarding secondary outcomes. The present study suggests that inadvertent prehospital EBI could be associated with a higher incidence of early-onset VAP. Larger studies are required to confirm this hypothesis. Whether strategies aimed at decreasing the incidence and duration of EBI could reduce the incidence of subsequent VAP remains to be determined.

Determining correct tracheal tube insertion depth by measuring distance between endotracheal tube cuff and vocal cords by ultrasound in Chinese adults: a prospective case-control study

OBJECTIVES

Unrecognised malposition of the endotracheal tube can lead to severe complications in patients under general anaesthesia. The purpose of this study was to verify the feasibility of using ultrasound to measure the distance between the upper edge of saline-inflated cuff and the vocal cords.

DESIGN

Prospective case-control study.

SETTING

A tertiary hospital in Beijing, China.

METHODS

In this prospective study, 105 adult patients who required general anaesthesia were enrolled. Prior to induction, ultrasound was used to identify the position of the vocal cords. After intubation, the endotracheal tube (ETT) was fixed at a depth of 23 cm at the upper incisors in men and 21 cm in women. The depth of intubation was verified by video-assisted laryngoscopy. The distance between the upper edge of the saline-inflated cuff and the vocal cords was measured by ultrasound; the ideal distance was considered to be 1.9-4.1 cm.

RESULTS

Among the 105 cases, two cuffs were too close to the vocal cords and one too far away from the vocal cords. These diagnoses were made by ultrasound and were in agreement with results from direct laryngoscopy. The overall accuracy of ultrasound in identifying malposition of the cuff was 100.0% (95% CI: 96.6% to 100%). The sensitivity, specificity, positive predictive value and negative predictive value of ultrasound were, respectively, 100% (95% CI: 96.5% to 100%), 100% (95% CI: 29.2% to 100%), 100% (95% CI: 96.5% to 100%) and 100% (95% CI: 29.2% to 100%).

CONCLUSION

Identification of the upper edge of the saline-inflated cuff and the vocal cords by ultrasound to assess the location of the ETT is a reliable method. It can be used to avoid malposition of the ETT cuff and reduce the incidence of vocal cords injury after intubation.

TRIAL REGISTRATION NUMBER

ChiCTR-DDD-17011048.

The Use of Point-of-Care Ultrasonography in Trauma Anesthesia

Caring for the trauma patient requires an in-depth knowledge of the pathophysiology of trauma, the ability to rapidly diagnose and intervene to reverse the derangements caused by shock states, and an aptitude for the use of advanced monitoring techniques and perioperative point-of-care ultrasonography (P-POCUS) to assist in diagnosis and delivery of care. Historically, anesthesiology has lagged behind in wholly embracing this technology. P-POCUS has the potential to allow the trauma anesthesiologist to diagnose numerous injuries, quickly guide the placement of central vascular catheters and invasive monitors, and assess the efficacy of interventions.

Changes in nasotracheal tube depth in response to head and neck movement in children

BACKGROUND

A tracheal tube is often inserted via the nasal cavity for dental surgery. The position of the tube tip is important, given that the head position sometimes changes during surgery. Head movement induces changes in the length of the trachea (t-length) and/or the distance between the nare and the vocal cords (n-v-distance). In this study, we investigated the changes in t-length and n-v-distance in children undergoing nasotracheal intubation.

METHODS

Eighty patients aged 2-8 year undergoing dental surgery were enrolled. After nasotracheal intubation with an uncuffed nasotracheal tube (4.5-6.0 mm), the tube was fixed at the patient's nares. The distance between the tube tip and the first carina was measured using a fibrescope with the angle between the Frankfort plane and horizontal plane set at 110°. The location of the tube in relation to the vocal cords was then checked. These measurements were repeated at angles of 80° (flexion) and 130° (extension). The t-length and n-v-distance were then calculated using these measurements.

RESULTS

On flexion, the t-length shortened significantly from 87.5 ± 10.4 mm to 82.9 ± 10.7 mm (P = 0.017) and the n-v-distance decreased from 128.1 ± 10.7 mm to 125.6 ± 10.4 mm (P = 0.294). On extension, the t-length increased significantly from 87.5 ± 10.4 mm to 92.7 ± 10.1 mm (P = 0.007) and the n-v-distance increased from 128.1 ± 10.7 mm to 129.4 ± 10.7 mm (P = 0.729). The change in t-length was significantly greater than that in the n-v-distance.

CONCLUSION

A change in the position of the tracheal tube tip in the trachea depends mainly on changes in t-length during paediatric dental surgery.

Point-of-care ultrasound versus auscultation in determining the position of double-lumen tube

This study was designed to assess the accuracy of point-of-care ultrasound in determining the position of double-lumen tubes (DLTs).A total of 103 patients who required DLT intubation were enrolled into the study. After DLTs were tracheal intubated in the supine position, an auscultation researcher and ultrasound researcher were sequentially invited in the operating room to conduct their evaluation of the DLT. After the end of their evaluation, fiberscope researchers (FRs) were invited in the operating room to evaluate the position of DLT using a fiberscope. After the patients were changed to the lateral position, the same evaluation process was repeated. These 3 researchers were blind to each other when they made their conclusions. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were obtained by statistical analysis.When left DLTs (LDLTs) were used, the accuracy of ultrasound (84.2% [72.1%, 92.5%]) was higher than the accuracy of auscultation (59.7% [45.8%, 72.4%]) (P < .01). When right DLTs (RDLTs) were used, the accuracy of ultrasound (89.1% [76.4%, 96.4%]) was higher than the accuracy of auscultation (67.4% [52.0%, 80.5%]) (P < .01). When LDLTs were used in the lateral position, the accuracy of ultrasound (75.4% [62.2%, 85.9%]) was higher than the accuracy of auscultation (54.4% [40.7%, 67.6%]) (P < .05). When RDLT were used, the accuracy of ultrasound (73.9% [58.9%, 85.7%]) was higher than the accuracy of auscultation (47.8% [32.9%, 63.1%]) (P < .05).Assessment via point-of-care ultrasound is superior to auscultation in determining the position of DLTs.

Prehospital Echocardiography During Resuscitation Impacts Treatment in a Physician-Staffed Helicopter Emergency Medical Service: an Observational Study

BACKGROUND

Patients in cardiac arrest must receive algorithm-based management such as basic life support and advanced (cardiac) life support. International guidelines dictate diagnosing and treating any factor that may have caused the arrest or may be complicating the resuscitation. Ultrasound may be of potential value in this process and can be used in a prehospital setting. The objective is to evaluate the use of prehospital ultrasound during traumatic and non-traumatic CPR and determine its impact on prehospital treatment decisions in a Dutch helicopter emergency medical service (HEMS).

METHODS

We conducted an observational study in cardiac arrest patients, of any cause, in whom the Nijmegen HEMS performed CPR with concurrent echocardiography. The participating physicians had to adhere to Advanced Life Support protocols as per standard operating procedure. Simultaneous with the interruptions of chest compressions to allow for heart rhythm analysis, ultrasound-trained HEMS physicians performed echocardiography according to study protocol. The HEMS nurse and physician recorded patient data and data on impacted (supported or altered) patient treatment decisions.

RESULTS

From February 2014 through November 2016, we included 56 patients who underwent 102 ultrasound examinations. Sixty-two (61%) ultrasound examinations impacted 78 treatment decisions in 49 patients (88%). The impacted treatment was related to termination of CPR in 32 (57%), fluid management (14%), drugs selection and doses (14%), and choice of destination hospital (5%). Causes of cardiac arrest included trauma (48%), cardiac (21%), medical (14%), asphyxia (9%), and other (7%).

CONCLUSION

Prehospital echocardiography has an impact on patient treatment and may be a useful tool to support decision-making during CPR in a Dutch HEMS.

Neurocognitive assessment in patients with a minor traumatic brain injury and an abnormal initial CT scan: Can cognitive evaluation assist in identifying patients who require surveillance CT brain imaging?

BACKGROUND

Evidence for repeat computed tomography (CT) in minor traumatic brain injury (mTBI) patients with intracranial pathology is scarce. The aim of this study was to investigate the utility of clinical cognitive assessment (COG) in defining the need for repeat imaging.

METHODS

COG performance was compared with findings on subsequent CT, and need for neurosurgery in mTBI patients (GCS 13-15 and positive CT findings).

RESULTS

Of 152 patients, 65.8% received a COG (53.0% passed). Patients with passed COG underwent fewer repeat CT (43.4% vs. 78.7%; p = .001) and had shorter LOS (8.7 vs. 19.5; p < .05). Only 1 patient required neurosurgery after a passed COG. The negative predictive value of a normal COG was 90.6% (95%CI = 81.8%-95.4%).

CONCLUSION

mTBI patients with an abnormal index CT who pass COG are less likely to undergo repeat CT head, and rarely require neurosurgery. The COG warrants further investigation to determine its role in omitting repeat head CT.

Point-of-care ultrasound (POCUS) of the upper airway

Airway management is a critical skill in the practice of several medical specialities including anesthesia, emergency medicine, and critical care. Over the years mounting evidence has showed an increasing role of ultrasound (US) in airway management. The objective of this narrative review is to provide an overview of the indications for point-of-care ultrasound (POCUS) of the upper airway. The use of US to guide and assist clinical airway management has potential benefits for both provider and patient. Ultrasound can be utilized to determine airway size and predict the appropriate diameter of single-lumen endotracheal tubes (ETTs), double-lumen ETTs, and tracheostomy tubes. Ultrasonography can differentiate tracheal, esophageal, and endobronchial intubation. Ultrasonography of the neck can accurately localize the cricothyroid membrane for emergency airway access and similarly identify tracheal rings for US-guided tracheostomy. In addition, US can identify vocal cord dysfunction and pathology before induction of anesthesia. A rapidly growing body of evidence showing ultrasonography used in conjunction with hands-on management of the airway may benefit patient care. Increasing awareness and use of POCUS for many indications have resulted in technologic advancements and increased accessibility and portability. Upper airway POCUS has the potential to become the first-line non-invasive adjunct assessment tool in airway management.

Measuring Endotracheal Tube Depth by Bedside Ultrasound in Adult Patients in an Intensive Care Unit: A Pilot Study

The aim of the study described here was to evaluate the feasibility and accuracy of measuring endotracheal tube (ETT) depth with ultrasound in adult patients in an intensive care unit (ICU). The distance between the upper margin of the cuff and the upper margin of the aortic arch (Duc-ua) of 67 ICU patients was measured by ultrasound, and the time of measurement was recorded. The level of agreement between the distance between the tip of the ETT and the carina (Dtt-c) measured by ultrasound (U-Dtt-c) and Dtt-c measured by bronchoscopy (B-Dtt-c) was assessed using linear regression and a Bland-Altman plot. There was a significant correlation between B-Dtt-c and U-Dtt-c (r = 0.844, p < 0.001). Also, the Bland-Altman plot revealed strong agreement between B-Dtt-c and U-Dtt-c. The time it took to measure ETT depth by ultrasound was 33.91 ± 5.43 s. In conclusion, bedside ultrasound provides a novel and convenient method for measuring the depth of ETT in ICU patients.

Preoxygenation using invasive ventilator in volume control mode in patients with emergency intubation can shorten the time of preoxygenation and improve the quality of preoxygenation: A retrospective study

Preoxygenation can rapidly improve oxygenation and enhance the security of endotracheal intubation, so it is very essential before endotracheal intubation. The conventional preoxygenation method self-inflating bag (SIB) is not very effective in case of emergency. So our study aims to find a more effective method of preoxygenation in a critical situation.We retrospectively analyzed data of 105 patients in this study. A total of 49 patients with preoxygenation with invasive ventilator in volume control mode (VCM) and 56 patients with preoxygenation with SIB were included. No significant differences were detected in the baseline data of the 2 groups (P > 0.05). Time of preoxygenation (95%) was 174 (168-180) seconds in group VCM and 205 (199-212) seconds in group SIB (P < 0.05), and multifactor linear regression showed that its main risk factors were the methods of preoxygenation and PO2 before preoxygenation (P < 0.05). Immediate SPO2 after preoxygenation was 91 (89-92)% in group VCM and 85 (83-86)% in group SIB (P < 0.05). Total time of preoxygenation and intubation was 266 (252-280) seconds in group VCM and 318 (298-338) seconds in group SIB (P < 0.05). The 24-hour and overall survival rate in group SIB were lower than in group VCM (P > 0.05). Cox regression showed that SaO2 at 5 minutes after intubation was the major risk factor for the survival rate.Invasive ventilator with volume control mode can shorten the time of preoxygenation and improve the quality of preoxygenation in patients with emergency intubation and may be a better method of preoxygenation in a critical situation.