الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Difficulties that occur during airway management are usually related to the intubator not being able to achieve an adequate view of the glottic opening to allow insertion of an endotracheal tube.
Fiberscopic intubation is a valuable technique in securing the airway in predicted difficult intubation scenarios, compromised airway, airway pathology and when neck extension is to be avoided.
In awake fiberscopic intubation using intravenous (IV) sedation, patient should remain calm and follow verbal commands. An ideal sedation regimen should provide patient comfort, cooperation, amnesia, haemodynamic stability, blunt airway reflexes, and maintain a patent airway with spontaneous ventilation.
Dexmedetomidine, an α2-adrenoreceptor agonist, is a valuable drug for fiberoptic intubation as it induces sedation and analgesia without depressing respiratory function. In addition, xerostomia is commonly reported by patients. These two effects make dexmedetomidine highly desirable for awake fiberscopic nasotracheal intubation.
The aim of this study was to compare the conditions of awake fiberscope guided nasotracheal intubation using intravenous versus nebulized dexmedetomidine as regards intubation conditions, effects of dexmedetomidine on haemodynamics, degree of sedation and the occurrence of drug related complications.
After approval of the Ethical Committee of Faculty of Medicine, Alexandria University and having an informed consent from every patient included in the study, the present study was carried out in Alexandria University Hospitals on thirty adult patients belonging to ASA physical status classification class I, II or III with anticipated difficult intubation and scheduled for elective surgery under general anaesthesia.
The sample size was approved to be sufficient by the Department of Statistics, High Institute of Public Health, University of Alexandria.
Patients were randomly allocated into two equal groups (fifteen patients each) using the closed envelope method:
group I (IV. Dex): Fifteen minutes before the fiberscope- guided nasal intubation, patients received loading dose of dexmedetomidine (1μg/kg) in 100 ml normal saline over 10 minutes intravenously then a maintenance dose of dexmeditomidine 0.1μg/kg/hr was infused intravenously till the end of the procedure. Nebulized lidocaine (1 mg/kg) using oxygen flow at 6L/min till the end of nebulized solution (15 minutes).
group II (Neb. Dex): Fifteen minutes before the fiberscope- guided nasal intubation, patients received 100 ml of normal saline over 10 minutes intravenously. An equal volume of normal saline will be infused intravenously after the loading dose and to be stopped at the end of the procedure. Nebulized dexmedetomindine (1μg/kg) with nebulized lidocaine (1mg/kg) using oxygen flow at 6L/min till the end of nebulized solution (15 minutes).
On arrival to the operating room, each patient was attached to a multi-channel monitor, cannulated with a 20 –gauge cannula and given oxygen 100% at 4 L/min through a nasal catheter.
Five minutes before the study, all patients received 50μg fentanyl IV, Xylometazoline nasal drops 0.1% (2 drops in each nostril). Two puffs of 10% lignocaine were instilled in each nostril and translaryngeal (or trans-tracheal) airway block was done. Then fiberscopic nasal intubation was performed.
Assessment of hemodynamic parameters, intubation conditions, depth of Sedation, any complications and the need of additional doses of propofol to increase the depth of sedation were measured.
There was no statistically significant differences as regards the sex, age & weight distribution in both studied groups.
Regarding heart rate changes, intravenous dexmeditomoidine did not result in any statistically significant changes after its administration (before nasal fiberscopy), in group I, releative to the baseline reading. However, the mean heart rate increased significantly after intubation. This was not the case in group II where the heart rate was statistically significantly higher than the baseline reading both after nebulization (before nasal fibersocpy) and after intubation. Comparing the two groups, there was a statistically significantly lower mean heart rate in group I than group II after administration of the drug by the assigned different route in each group. This significantly lower heart rate in group I may indicate a more deeper depth of sedation in this group.
Regarding the arterial blood pressure changes, in the intravenous group, the systolic and mean arterial blood pressure increased statistically significantly relative to the basic reading and the diastolic blood pressure increased statistically significantly relative to the baseline values only after intubation. In the nebulized group, only the diastolic and the mean arterial blood pressure increased significantly relative to the basic reading after intubation. Comparing the two groups, statistically significant decrease in the systolic, diastolic and mean arterial blood pressure were detected in group I relative to group II after drug administration through the different routes.
No ECG changes were detected in the two studied groups all over the study period.
Comparing the two groups, there was no statistically significant difference in the mean oxygen saturation before starting of sedation, before the start of fiberoscopy and immediately after intubation.
In the present study, several parameters were studied to evaluate the overall conditions during the intubation procedure. These were the duration of the procedure, number of trials, vocal cord movement score and coughing score.
Despite higher percent of cases ( 14 cases) (93.3%) being intubated from the first trail in group I relative to only 10 cases (66%) in group II, this was not statistically significant. In addition, there was no significant difference between the two groups in the duration needed for successful intubation.
Vocal cord movements during intubation showed a statistical variation between the two groups, where zero percentage of cases in group I and 73.3% of cases (11 cases) in group II scored 1. The score was 2 in 80% of cases in group I (12 cases) and 26.7% (4 cases) in group II. The score was 3 in 20% of cases (3 cases) in group I and zero% of cases in group II. None of the cases in both groups scored 4.
Coughing during intubation showed no statistical variation between the two groups, where the score was 1 in 66.7 % of cases (10 cases) in group I and 53.3 % of cases in group II (8 cases). The score was 2 in 6.7% of cases in group I (single case) and 33.3% in group II (5 cases). The score was 3 in 20% of cases in group I (3 cases) and 6.7% of cases in group II( single case). 6.7 % the cases in both groups scored 4 (single case in each group).
All cases in both groups were successfully intubated.
Regarding the depth of sedation, it was assessed by the Ramsey sedation score and patient tolerance (facial grimace) score.
There was wide variation between the two groups, where the score was 1 in 13.3% of cases in group I and 80% of cases in group II. The score was 2 in 86.7% of cases in group I and 20% in group II. None of the cases in both groups scored 3, 4 or 5. The score showed a statistically significant difference between the two groups with a p value of <0.001.
Regarding the patient tolerance score ,the score was 1 in 6.7 % of cases in both groups I & II. The score was 2 in 73.3% of cases in group I and 46.7% in group II. The score was 3 in 13.3% of cases in group I and 13.3% of cases in group II and the score was 4 in 6.7% of the cases of group I and 33.3% of the cases in group II. None of the cases in both groups scored 5 or 6. The score showed no statistically significantly difference between the two groups with a p value of 0.268.
Some complications were encountered during the study. In group I hypotension, postoperative hoarseness of the voice, nasal trauma & bronchospasm. In group II nasal trauma, desaturation and bradycardia and hypotension 5 minutes after the end of fiberoscopy with no statistically significant difference between both groups.
Additional doses of propofol where needed in two cases in group I and a single case in group II.