Upper Airway Ultrasound Evaluation
Trial statusRecruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18-99
SponsorUniversity of Ioannina
About this trial
Current guidelines support the use of predictive clinical tests in the evaluation of difficult airway, meaning either difficult bag and mask ventilation, conventional laryngoscopy and/or endotracheal intubation. However, despite the clinical use of these predictive tests, unpredictive difficult laryngoscopy complicates 1.5-13% of cases. Life threatening scenarios may be encountered in patients with difficult or impossible bag and mask ventilation.
Anaesthesiologists are familiar with the use of ultrasound, with peripheral nerve blockade and central vascular access representing the most popular applications during the last decades. The ultrasound provides real time and accurate images. According to the current literature, there are only a handful of studies relevant to the application of point of care ultrasound (POCUS), as a new tool in the upper airway evaluation. It is a new field of research with high interest.
This is a prospective observational study to investigate if specific ultrasound measurements of the anterior neck can serve as predictors of difficult airway. The ultrasound parameters will be measured preoperatively, during the preanaesthetic evaluation, along with standard clinical prognostic tools, like the mallampati score. The ultrasound parameters to be investigated are:
1. the distance from thyroid isthmus to skin surface, 2. the distance from the hyoid bone to the skin surface, 3. the distance from the anterior commissure of vocal cords to the skin surface, 4. the distance from skin to the trachea at the level of jugular notch, 5. the distance from skin to epiglottis corresponding to half of the distance between thyroid cartilage and hyoid bone, 6. and the angle between glottis and epiglottis. After the induction in anaesthesia, the Cormack Lehane score (grading of the laryngoscopy view) and the Han scale (grading of the degree of difficulty of bag and mask ventilation) will also be recorded.
The goal of this study is the investigation of the role of POCUS in the evaluation of difficult bag and mask ventilation and difficult intubation. The primary endpoint is the incidence of difficult bag and mask ventilation and the incidence of difficult laryngoscopy and intubation. Secondary endpoints are the correlations between clinical prognostic tools of difficult airway and the POCUS parameters under investigation.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
None
Disqualifiers
obstetric surgeries,
pregnancy,
non elective surgeries,
patients with previous surgeries involving the anterior surface of the neck (i.e., thyroid surgery),
Trial population
General surgical population.
Trial design
Design model
Cohort
Time perspective
Prospective
Treatments tested in this trial
point of care ultrasound
Diagnostic testPoint of care ultrasound for upper airway evaluation.
Treatment groups
No treatment groups listed
Trial outcomes
Primary outcomes
1
Incidence of difficult intubation
Difficult intubation is defined as requirement of more than three attempts with conventional laryngoscopy.
Time frame
From the beginning of the pre-oxygenation period up to securing the airway, with either up to 3 attempts of conventional laryngoscopy/intubation, or non-conventional intubation, or waking up the patient, whichever comes first.2
Incidence of difficult bag and mask ventilation
Difficult mask ventilation is defined as the inability of an unassisted anesthesiologist to maintain the measured oxygen saturation as measured by pulse oximetry \> 92% or to prevent or reverse signs of inadequate ventilation during positive-pressure mask ventilation under general anesthesia.
Time frame
From the beginning of the pre-oxygenation period up to securing the airway, with either up to 3 attempts of conventional laryngoscopy/intubation, or non-conventional intubation, or waking up the patient, whichever comes first.Secondary outcomes
1
Cormack-Lehane classification
Classifies laryngoscopy views obtained by direct laryngoscopy based on the structures seen (Grade I: visualization of the entire laryngeal aperture; Grade II: visualization of only the posterior commissure of the laryngeal aperture; Grade III: visualization of only the epiglottis; Grade IV: visualization of only the soft palate).
Time frame
From the beginning of the pre-oxygenation period up to the first, second or third attempt of conventional laryngoscopy, whichever comes first.2
Han scale classification
Classifies the difficulty in bag and mask ventilation (Grade I: easy mask ventilation, Grade II: needs oral airway or adjuvant with or without neuromuscular blocking agents, Grade III: difficult - inadequate or unstable or requiring two care providers, with or without neuromuscular blocking agents, Grade IV: impossible - unable to mask ventilate with or without neuromuscular blocking agents).
Time frame
From the beginning of the pre-oxygenation period up to securing the airway, with either up to 3 attempts of conventional laryngoscopy/intubation, or non-conventional intubation, or waking up the patient, whichever comes first.3
Distance from thyroid isthmus to skin surface
Ultrasound measurement of the distance from thyroid isthmus to skin surface with the probe in the transverse axis.
Time frame
24 hours before elective surgery and general anaesthesia needing endotracheal intubation, during the pre-anesthetic visit.4
Distance from hyoid bone to skin surface
Ultrasound measurement of the distance from hyoid bone to skin surface with the probe in the transverse axis.
Time frame
24 hours before elective surgery and general anaesthesia needing endotracheal intubation, during the pre-anesthetic visit.Sponsors and contacts
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Source ClinicalTrials.gov