Upper airway ultrasound is a valuable, non-invasive, simple, and portable point of care ultrasound (POCUS) for evaluation of airway management even in anatomy distorted by pathology or trauma. Ultrasound enables us to identify important sonoanatomy of the upper airway such as thyroid cartilage, epiglottis, cricoid cartilage, cricothyroid membrane, tracheal cartilages, and esophagus. Understanding this applied sonoanatomy facilitates clinician to use ultrasound in assessment of airway anatomy for difficult intubation, ETT and LMA placement and depth, assessment of airway size, ultrasound-guided invasive procedures such as percutaneous needle cricothyroidotomy and tracheostomy, prediction of postextubation stridor and left double-lumen bronchial tube size, and detecting upper airway pathologies. Widespread POCUS awareness, better technological advancements, portability, and availability of ultrasound in most critical areas facilitate upper airway ultrasound to become the potential first-line non-invasive airway assessment tool in the future.
BackgroundIn emergency settings, verification of endotracheal tube (ETT) location is important for critically ill patients. Ignorance of oesophageal intubation can be disastrous. Many methods are used for verification of the endotracheal tube location; none are ideal. Quantitative waveform capnography is considered the standard of care for this purpose but is not always available and is expensive. Therefore, this feasibility study is conducted to compare a cheaper alternative, bedside upper airway ultrasonography to waveform capnography, for verification of endotracheal tube location after intubation.MethodsThis was a prospective, single-centre, observational study, conducted at the HRPB, Ipoh. It included patients who were intubated in the emergency department from 28 March 2012 to 17 August 2012. A waiver of consent had been obtained from the Medical Research Ethics Committee. Bedside upper airway ultrasonography was performed after intubation and compared to waveform capnography. Specificity, sensitivity, positive and negative predictive value and likelihood ratio are calculated.ResultsA sample of 107 patients were analysed, and 6 (5.6%) had oesophageal intubations. The overall accuracy of bedside upper airway ultrasonography was 98.1% (95% confidence interval (CI) 93.0% to 100.0%). The kappa value (Κ) was 0.85, indicating a very good agreement between the bedside upper airway ultrasonography and waveform capnography. Thus, bedside upper airway ultrasonography is in concordance with waveform capnography. The sensitivity, specificity, positive predictive value and negative predictive value of bedside upper airway ultrasonography were 98.0% (95% CI 93.0% to 99.8%), 100% (95% CI 54.1% to 100.0%), 100% (95% CI 96.3% to 100.0%) and 75.0% (95% CI 34.9% to 96.8%). The likelihood ratio of a positive test is infinite and the likelihood ratio of a negative test is 0.0198 (95% CI 0.005 to 0.0781). The mean confirmation time by ultrasound is 16.4 s. No adverse effects were recorded.ConclusionsOur study shows that ultrasonography can replace waveform capnography in confirming ETT placement in centres without capnography. This can reduce incidence of unrecognised oesophageal intubation and prevent morbidity and mortality.Trial registrationNational Medical Research Register NMRR11100810230.
Aims
Non-invasive ventilation represents an established treatment for acute cardiogenic pulmonary oedema (ACPO) although no data regarding the best ventilatory strategy are available. We aimed to compare the effectiveness of helmet CPAP (hCPAP) and high flow nasal cannula (HFNC) in the early treatment of ACPO.
Methods and results
Single-centre randomized controlled trial of patients admitted to the emergency department due to ACPO with hypoxemia and dyspnoea on face mask oxygen therapy. Patients were randomly assigned with a 1:1 ratio to receive hCPAP or HFNC and FiO2 set to achieve an arterial oxygen saturation >94%. The primary outcome was a reduction in respiratory rate; secondary outcomes included changes in heart rate, PaO2/FiO2 ratio, Heart rate, Acidosis, Consciousness, Oxygenation, and Respiratory rate (HACOR) score, Dyspnoea Scale, and intubation rate. Data were collected before hCPAP/HFNC placement and after 1 h of treatment. Amongst 188 patients randomized, hCPAP was more effective than HFNC in reducing respiratory rate [−12 (95% CI; 11–13) vs. −9 (95% CI; 8–10), P < 0.001] and was associated with greater heart rate reduction [−20 (95% CI; 17–23) vs. −15 (95% CI; 12–18), P = 0.042], P/F ratio improvement [+149 (95% CI; 135–163) vs. +120 (95% CI; 107–132), P = 0.003] as well as in HACOR scores [6 (0–12) vs. 4 (2–9), P < 0.001] and Dyspnoea Scale [4 (1–7) vs. 3.5 (1–6), P = 0.003]. No differences in intubation rate were noted (P = 0.321).
Conclusion
Amongst patients with ACPO, hCPAP resulted in a greater short-term improvement in respiratory and hemodynamic parameters as compared with HFNC.
Trial registration
Clinical trial submission: NMRR-17-1839-36966 (IIR). Registry name: Medical Research and Ethics Committee of Malaysia Ministry of Health. Clinicaltrials.gov identifier: NCT04005092. URL registry: https://clinicaltrials.gov/ct2/show/NCT04005092.
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