General Anesthesia, Pulmonary Aspiration
Conditions
Keywords
Laryngeal mask airway, Paratracheal esophageal pressure, Cricoid pressure
Brief summary
Laryngeal mask airway is inserted into the oral cavity and seals the upper esophagus and the surrounding tissue, effectively securing airway. Laryngeal mask airway has been widely adopted in the clinical practice. On the other hand, cricoid pressure has been used to reduce the risk of pulmonary aspiration of gastric contents during induction of general anesthesia. However, cricoid pressure might impede placement of the laryngeal mask airway, thereby preventing effective ventilation. Recently, left paratracheal pressure was introduced as an alternative to cricoid pressure and reported to be more effective than cricoid pressure in the prevention of gastric air insufflation during positive-pressure ventilation by facemask. Since this method compresses low left paratracheal level, it may affect the successful insertion of laryngeal mask airway. In this study, the investigators aimed to evaluate the effect of paratracheal esophagus pressure on the insertion of laryngeal mask airway compare to conventional cricoid pressure.
Interventions
PROCEDUREParatracheal pressure
To apply paratracheal pressure, the thumb was placed over the left side of the trachea cephalad to the clavicle and medial to the sternocleidomastoid muscle.
PROCEDURECricoid pressure
To apply cricoid pressure, the cricoid cartilage is compressed by 30N force with a single-handed three finger maneuvre towards the vertebral bodies.
Sponsors
Ajou University School of Medicine
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
The group assignments were sealed in opaque envelopes by a research assistant not involved in the study.
Intervention model description
Randomized double blinded clinical trial
Eligibility
Sex/Gender
ALL
Age
19 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Patients who are undergoing surgery under general anesthesia where supraglottic airway management will be appropriate * American Society of Anesthesiologists Classification 1-2
Exclusion criteria
* Body mass index \> 35 kg/m2 * High risk of regurgitation (hiatus hernia, gastro-esophageal reflux disease, non-fasting status) * Criteria for difficult airway (limitation of mouth opening/neck extension, Mallampati class IV),
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The success rate of device insertion | During induction of anesthesia, an average of 60 seconds | Successful insertion of laryngeal mask airway in a maximum of three attempts |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| The time for successful insertion of the device | : During induction of anesthesia, an average of 60 seconds | The total time is measured from the removal of the face mask until bilateral chest rise with the first capnogram upstroke. |
| Peak inspiratory pressure | At 5 minute after insertion of laryngeal mask airway | Peak inspiratory pressure is recorded from mechanical ventilator. |
| The ease of insertion of device | During induction of anesthesia, an average of 60 seconds | The ease of placement was assessed using a subjective scale of 1-4 (1= no resistance, 2 = moderate resistance, 3 = high resistance, 4 = inability to place the device |
| The number of attempts at insertion of device | During induction of anesthesia, an average of 60 seconds | The number of attempts for successful insertion of laryngeal mask airway |
| The grade of fiberoptic bronchoscopic view | During induction of anesthesia, an average of 5 minutes | The fiberoptic bronchoscopic view is defined as Grade 1, larynx only seen; Grade 2, larynx and epiglottis posterior surface seen; Grade 3, larynx, and epiglottis tip or anterior surface seen-visual obstruction of epiglottis to larynx: \< 50%; Grade 4, epiglottis down-folded, and its anterior surface seen-visual obstruction of epiglottis to larynx: \> 50%; Grade 5, epiglottis downfolded and larynx cannot be seen directly. |
| Incidence of intraoperative complications | During the surgery, an average of 2 hours after anesthesia induction | Intraoperative complications including coughing, laryngospasm, bronchospasm, hypoxia (SpO2 \< 90%), regurgitation, aspiration, blood staining of the device. |
| Incidence of postoperative complications | An average of 2 hours after extubation | Postoperative complications including sore throat, hoarseness/dysphonia, jaw, neck or ear pain, persistent cough, tachypnea, stridor, hypoxia (SpO2 \< 90%), nausea and vomiting. |
| The presence of gastric air insufflation after induction of anesthesia | During induction of anesthesia, an average of 5 minutes | The presence of gastric air insufflation is defined as an increase in antral cross-sectional area and/or presence of air artifacts in the antrum (comet tail, posterior acoustic shadow) confirmed by ultrasound. |
| Success rate in first attempt | : During induction of anesthesia, an average of 60 seconds | Successful insertion of laryngeal mask airway in a first attempt |
Countries
South Korea
Outcome results
None listed