Atomization vs. Nebulization for Airway Topicalization During Awake Nasotracheal Fiberoptic Intubation

  • STATUS
    Recruiting
  • participants needed
    52
  • sponsor
    Zagazig University
Updated on 24 June 2022

Summary

Intubation of difficult airway is a challenge for anesthetist. There many causes of difficult airway, and previous studies concluded that awake fiber-optic intubation (AFOI) is the gold standard for the management of these patients. Several studies showed that airway nerve blocks provide rapid and deep airway anesthesia, however, due to their several disadvantages, topicalization of the airway represents a promising alternative to them. Some studies revealed that nebulization and atomization of the airway provide adequate anesthesia for AFOI. In the present study, we try to find out which is more effective for topicalization of the airway during nasotracheal AFOI; nebulization or atomization.

Description

Site of the Study: Zagazig university surgical hospitals.

Type of the Study: Prospective randomized double-blinded clinical trial.

Sample Size:

The sample size is calculated to be 52 cases (26 for each group), using open epi program with confidence level of 95% and power of test 80%, assuming that the mean ± standard deviation of intubation time among patients undergoing nebulization and atomization techniques is 200.4 ± 24.4 and 184.9 ± 13.3, respectively.

Withdrawal Criteria:

The patient has the right to withdraw from the study at any time without any negative consequences on medical or surgical treatment plan.

Randomization

Group I: will receive Nebulization with lidocaine, Group II: will receive Atomization with lidocaine.

Computer-generated randomization numbers will be used to randomly assign patients into 2 groups using sealed opaque envelopes that will be randomly selected by each patient and contained a group number in which patient was enrolled. Once enrolled in the study, patients will be randomly assigned into 2 groups; Both the anesthesiologist performing the fibroscopy and the data collector will be blind to group assignment.

Type of the Study: Prospective randomized double-blinded clinical trial.

Steps of Performance:

Preoperative Assessment:

A complete preoperative evaluation including a thorough airway evaluation (mouth opening, Mallampati grade, thyromental distance (TM) and neck movements) will be performed.

All patients will be assessed by history taking, clinical examination and laboratory investigations, which will include; Complete blood count (CBC), Prothrombin time and concentration (PT and PC), Partial thromboplastin time (PTT), International normalized ratio (INR), liver and kidney function tests. Other investigations (e.g., electrocardiography, echocardiography, and chest x-ray) will be done according to patient's medical condition.

Preoperative Preparation:

Procedure explanation will be done the day before surgery, and informed written consent will be obtained from patients after discussing with them the cause of performing the procedure, its benefits and possible complications that may occur. Standard fasting guidelines will be also explained to the patients.

In the Procedure Area:

Premedication, nasal preparation and topicalization technique will be performed by independent anesthesiologist in the procedure area, where patient's vital signs are monitored, then the patient will be shifted to the operating room where fibroscopy and intubation will be performed by another blinded anesthesiologist. The procedure area is equipped for emergency management and close monitoring of the patient.

  1. Monitoring:

Monitoring will be applied and maintained throughout the procedure, including 5- lead electrocardiogram (ECG), non-invasive arterial blood pressure, pulse oximeter, and capnography. Hemodynamic parameters heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and oxygen saturation (SpO2) will be recorded, as control recordings before sedation and after Ramsay sedation score 2.

B. Premedication:

After ensuring of working 18 gauge intravenous (IV) line, IV fluids will be administered. All patients will receive IV bolus doses of the following; Atropine 0.5 mg IV as anti-sialagogues. Midazolam (20 - 50 μg/kg) as sedative. Fentanyl (0.5- to 1.5-µg/kg) as analgesic and antitussive. Midazolam and fentanyl doses will be titrated according to the patient's level of sedation with target to obtain a cooperative, oriented and tranquil patient (Ramsay sedation score of 2).

C. Nasal Preparation:

All patients' nostrils will be instilled with Xylometazoline 1% nasal drops (2-3 drop for each nostril). Anesthesia of the nasal mucosa will be achieved by application of 3 cotton swabs soaked in 2 mL of 2% lidocaine solution. The cotton swabs will be introduced into the preferred nostril, one at a depth of 1.5 cm superiorly (to block the branches of ethmoidal nerves), and two at a depth of 2-2.5 cm (to block the sphenopalatine ganglion and branches of the maxillary division of the trigeminal nerve). The swabs will be kept in place for 3 min.

The preferred nostril for FOI will be then progressively dilated with silicone nasopharyngeal airway starting 6.5 up to 7.5 mm smeared with 2% lidocaine jelly. The nasopharyngeal airway will be removed immediately before fibroscopy. This method allows for lubrication of the nasal passages and also ensures that these passages are patent and likely large enough for the ETT.

D. Topicalization Technique:

After ensuring adequate nasal preparation, the patient's envelope which contains the number of group will be opened and it will be recorded in the data collection sheet as a number of group because the data collector will be blind to the intervention which will be done to the patient, only the anesthetist knows each number will be referring to which intervention.

Group I: will receive Nebulization with lidocaine. Group II: will receive Atomization with lidocaine. To ensure investigator blinding, nebulization and atomization will be administered by an independent anesthesiologist, and the patient will be then moved from the procedure area to the operating room where, after recording the vital signs, another blinded senior anesthesiologist, with previous experience in FOI, will perform the procedure.

  1. Nebulization Technique:

A face mask nebulizer with oxygen flow rate of 8 L/min will be used to deliver 10 mL of 2% lidocaine. Patients will be encouraged to inhale deeply to facilitate entrainment of nebulized LA into their airway. Adequate topical anesthesia will be confirmed by heaviness or numbness of the tongue.

2. Atomization Technique (McKenzie Technique):

A 20-gauge cannula will be attached to oxygen bubble tubing via a three-way tap. The other end of bubble tubing will be then attached to an oxygen source, which will turned on to deliver a flow of 8 L/min. a 10-mL syringe filled with 2% lidocaine will be attached to the top port of the cannula.

As LA is slowly atomized as a jet-like spray, the cannula will be directed towards the soft palate and posterior pharynx in a controlled fashion during patients' inspiration to topicalize the airway. Patients will be asked to take full vital capacity breaths of atomized LA contained oxygen to anaesthetize the pharynx, glottis and subglottic structures. Adequate topical anesthesia will be confirmed by heaviness or numbness of the tongue.

In the Operating Room:

  1. Monitoring:

The same monitoring as in the procedure area will be applied and maintained throughout the procedure, including 5- lead electrocardiogram (ECG), non-invasive arterial blood pressure, pulse oximeter, and capnography.

Hemodynamic parameters heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and oxygen saturation (SpO2) will be recorded, as follows:

  1. At the beginning of the fibroscopy. 2. After entry of the FOB in the trachea.
  2. After advancing the ETT through the nasopharynx. 4. Immediately post-intubation. 5. 1, 3 and 5 min. post-intubation. Hemodynamic monitoring will be concluded after 5 min post-intubation.
  3. Fibroscopy & Intubation:

After ensuring adequate sedation and optimal topical anesthesia, a fiberoptic scope (Pentax® FI-16BS, 5.2mm; Japan) loaded with an appropriate size ETT (size 7.0-7.5 mm internal diameter for male patients and size 6.5-7.0 mm for female patients) will be inserted nasally into the chosen nostril after removal of the nasopharyngeal airway.

Supplemental oxygen (2 L/min) will be delivered through the working channel of the FOB for oxygenation and prevention of mucosal webbing of the tip of the instrument. Any hypoxic episode (SPO2 < 90%) during intubation will be recorded.

Supplemental LA will be given as 2 ml aliquots of 2% lidocaine through the working channel of FOB by spray-as-you-go technique (next aliquot given only after waiting for 30-60 sec.).

Bronchoscopy-guided intubation time will be calculated as the time from passing the flexible fiberoptic bronchoscope tip through the nostril to the first reading obtained by the capnograph after endotracheal intubation.

Once the position of the fiberscope in the trachea is confirmed, the tracheal tube will be railroaded and positioned approximately 3 cm above the carina and secured. After the confirmation of ETT position by auscultation and capnography, GA will be administered with Propofol 2 mg/ kg and Rocuronium 0.6 mg/kg IV were administered and the patient will be connected to the ventilator.

Total LA Dose:

The total dose of lidocaine administered will be limited to 6 mg/kg which is lesser than the maximum recommended dose. For example, for 70 kg patient, the following LA doses will be used in each step; Nasal Preparation; 2 mL of 2% lidocaine (40 mg), 2% lidocaine jelly (100 mg), Nebulization or Atomization; 10 mL of 2% lidocaine (200 mg) SAYGO; 2 mL + 2 mL of 2% lidocaine (80 mg), Total Dose; 420 mg

Assessment of the Quality of AFOI:

The quality of AFOI will be measured using intubating condition score, vocal cord position score, intraoperative patient comfort score and postoperative patient satisfaction score, as shown below.

Intubating Condition Score:

  1. Optimal; No hold-up or collision of tracheal tube with vocal cords.
  2. Suboptimal; Hold-up relieved by one rotation of the tube.
  3. Difficult; Hold-up requiring more than one rotation of the tube.
  4. Failure; Failed attempt at awake fiberoptic intubation.

Vocal Cord Position Score:

1; Relaxed, 2; Partially Relaxed and 3; Adducted.

Intraoperative Patient Comfort Score:

  1. Cough & Gag Severity:

1; None, 2; Minimal coughing or gagging (< 3 times) like "clearing throat", 3; Mild coughing or gagging lasting < 1 min., and 4; Persistent coughing or gagging.

B. Comfort during Intubation:

1; No reaction, 2; Slight grimacing, 3; Severe grimacing, 4; Verbal objection, and 5; Defensive movements of head, hands, or feet.

C. Post-intubation Assessment:

1; Cooperative, 2; Restless/minimal resistance, and 3; Severe resistance/ requirement for immediate general anesthesia.

Postoperative Patient Satisfaction Score:

1; Excellent, 2; Good, 3; Fair and 4: Poor.

Parameters including intubating condition and vocal cord position will be recorded by the anesthesiologist performing the fiberoptic bronchoscopy-guided intubation, while intubation time, patient comfort and vital signs will be recorded by another independent observer who will be blinded to group assignment.

Measured Parameters:

  1. Hemodynamics; Vital signs including; heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and oxygen saturation (SpO2) will be recorded, as follows:
  2. Control recordings before sedation. 2. After Ramsay sedation score 2. 3. At the beginning of the fibroscopy. 4. After entry of the FOB in the trachea.
  3. After advancing the ETT through the nasopharynx. 6. Immediately post-intubation. 7. 1, 3 and 5 min. post-intubation. Hemodynamic monitoring was concluded after 5 min. post intubation.
  4. Bronchoscopy-guided Intubation Time; will be measured as the time from passing the flexible fiberoptic bronchoscope tip through the nostril to the first reading obtained by the capnograph after endotracheal intubation.
  5. Quality of AFOI; will be measured by intubating condition score, vocal cord position score, intraoperative patient comfort score and postoperative patient satisfaction score.
    Complications

Hoarseness, sore throat or any signs of lidocaine toxicity such as tinnitus, perioral tingling, seizures or cardiovascular collapse, will be recorded.

Details
Condition Awake Fiberoptic Intubation
Treatment Nebulization with lidocaine, Atomization with lidocaine
Clinical Study IdentifierNCT05320731
SponsorZagazig University
Last Modified on24 June 2022

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