|ORIGINAL ARTICLE - INTERVENTION PULMONOLOGY
|Year : 2020 | Volume
| Issue : 2 | Page : 358-363
Assessment of the efficacy of nebulized local anesthesia using continuous positive airway pressure during fibroptic bronchoscopy
Adel M Saeed, Haytham S Diab, Mayada A.H Abdel Hakim
Department of Chest Diseases, Ain Shams University, Cairo, Egypt
|Date of Submission||04-Jun-2019|
|Date of Decision||26-Jul-2019|
|Date of Acceptance||04-Aug-2019|
|Date of Web Publication||14-May-2020|
Haytham S Diab
Source of Support: None, Conflict of Interest: None
Background The administration of nebulized lidocaine before fiberoptic bronchoscopy (FOB) is preferred than conventional lidocaine spray methods in reducing complications, reducing the need for additional lidocaine doses, and decreasing the incidence of lidocaine adverse effects. The use of nebulized lidocaine through continuous positive airway pressure (CPAP) seems to be superior owing to rapid and deep deposition of the anesthetic agent. The aim of this research is to study if the use of nebulized lidocaine through CPAP is superior to the conventional methods of lidocaine spray before FOB.
Patients and methods An observational prospective cohort study was performed in the Chest Department at Ain Shams University hospitals on 40 patients subjected to FOB. They were randomly divided into two groups: group A included 20 patients who underwent FOB using nebulized lidocaine through CPAP, and group B included 20 patients who underwent FOB using conventional lidocaine spray. After doing FOB, we noticed the need for additional doses of lidocaine to complete FOB, duration of FOB, easy entry of the FOB, and incidence of complications.
Results Interestingly, patients in group A needed less additional doses of lidocaine spray to complete FOB. Moreover, they had less incidence of coughing and occurrence of gag reflex during FOB, and also less patients’ discomfort, but both duration of FOB and easy entry of the FOB are the same in both groups.
Conclusion Administration of nebulized lidocaine through CPAP before FOB leads to decreased use of lidocaine with less incidence of its adverse effects when compared with conventional method of lidocaine spray, and also it has better patient acceptance than lidocaine spray owing to its unpleasant taste. So it should be recommended for use before FOB on a wider scale.
Keywords: continuous positive airway pressure, fiberoptic bronchoscopy, nebulized lidocaine, lidocaine spray
|How to cite this article:|
Saeed AM, Diab HS, Abdel Hakim MA. Assessment of the efficacy of nebulized local anesthesia using continuous positive airway pressure during fibroptic bronchoscopy. Egypt J Chest Dis Tuberc 2020;69:358-63
|How to cite this URL:|
Saeed AM, Diab HS, Abdel Hakim MA. Assessment of the efficacy of nebulized local anesthesia using continuous positive airway pressure during fibroptic bronchoscopy. Egypt J Chest Dis Tuberc [serial online] 2020 [cited 2020 Aug 3];69:358-63. Available from: http://www.ejcdt.eg.net/text.asp?2020/69/2/358/284293
| Introduction|| |
Fiberoptic bronchoscopy (FOB) appeared first in 1966, and the indications of FOB have changed over the years. It involves examination of tracheobronchial tree. FOB is used for many diagnostic (bronchoalveolar lavage and endobronchial and transbronchial biopsies) and therapeutic (foreign body removal, mucus plugs, blood clots, and treating central airway obstruction with stents positioning) indications. FOB is safe and simple . Rigid bronchoscope needs general anesthesia, whereas FOB can be performed under local anesthesia, with avoidance of complications of general anesthesia. Furthermore, FOB can be done as an outpatient procedure without the need for hospitalization. Moreover, FOB can be used to examine upper lobes and bronchial subsegments that cannot be examined by a rigid bronchoscope .
FOB is a vital manoeuver for the diagnostic workup and management of different chest diseases. It is done with local anesthesia and sedatives to improve patient tolerability, as recommended by recent guidelines .
Cocaine, benzocaine, tetracaine, and lidocaine all are effective, but lidocaine is the most common local anesthetic agent used owing to its good safety profile . There are many lidocaine preparation and different methods of delivery. Lidocaine maintains the nerves’ cell membrane, so preventing the induction of action potentials. Local lidocaine applied to upper respiratory tract through the bronchoscopy channel decreases the occurrence of cough and stridor and the need for sedative drugs .
Incidence of lidocaine adverse effects increases when blood serum exceeds 5 mg % in patients with hepatic dysfunction or 8 mg % in normal persons. Lidocaine toxicity can lead to arrhythmias, convulsions, cardiorespiratory arrest, and uncommon death .
Spraying lidocaine has unpleasant taste and smell to the patients, as it may lead to difficulty and pain during swallowing .
Lidocaine can be administered by nebulization. Its dose is small and effective for bronchoscopy as it may be less than oral spraying. Nebulized lidocaine delivers the drug deeply to airways in a small and safe doses for anesthetic effect, so FOB becomes comfortable and uneventful for patients .
The ideal effect of lidocaine is associated with the amount, more than lidocaine concentration. A randomized study using lidocaine spray technique compared different concentrations of lidocaine 1% and 2% with the same volume, applied to tracheobronchial tree, and revealed the same effects of cough suppression . Moreover, many recent studies revealed the same concept .
In this limited research, we explored whether the use of nebulized lidocaine through continuous positive airway pressure (CPAP) (which is not studied before) is superior to the conventional methods of lidocaine delivery (lidocaine spray) before FOB.
| Patients and methods|| |
An observational prospective cohort study was performed in the Chest department at Ain Shams University hospitals on 40 patients subjected to FOB from September 2018 to April 2019. All the included patients in the present study were randomly categorized into two groups: group A comprised twenty patients who underwent FOB using nebulized local anesthesia (lidocaine) through CPAP, and group B comprised twenty patients who underwent FOB using local anesthesia (lidocaine) with the conventional method (lidocaine spray 10%, 6–8 puffs). Patients with the following criteria were excluded from the study: presence of emphysematous bullae, excess respiratory secretions and risk of aspiration, maxillo-facial deformities preventing mask fitting, disapproval of participation, and poor patient co-operation.
Informed consent was attained from all patients or the relatives with respect to confidentiality and respect for their privacy. The study was accepted by the institutional research and ethics committee in June 2018.
Study end points
Primary end point was to reveal the additional doses of administered lidocaine during FOB in both studied groups.
Secondary end points were to reveal occurrence of complications during FOB such as cough frequency, occurrence of gag reflex, and patients’ discomfort, in addition to determine how the easiness of the FOB entry and to compare the duration of FOB in both studied groups.
All the procedures were done by an experienced physician. Continuous monitoring of oxygen saturation and blood pressure was done regularly during FOB. Oxygen was given at 3 l/min by nasal cannula to all patients. If oxygen level decreased less than 90%, oxygen flow rate was elevated to 6 l/min.
The following parameters were recorded before, during, and after the FOB: initial and lowest oxygen saturation and maximum oxygen flow, initial blood pressure and after the end of FOB, initial and highest heart rate, monitored ECG changes and any occurrence of arrhythmia, and additional lidocaine doses.
During and after doing FOB, the following inquiries were identified: need for additional doses of lidocaine to complete FOB, duration of FOB, easy entry of the FOB, coughing during FOB, occurrence of gag reflex, and patients’ discomfort during FOB.
Continuous positive airway pressure
Special modification was done by an expert technician on CPAP device to introduce a nebulizer stream together with CPAP airflow in a ‘Y’ manner before the CPAP mask to allow delivery of the nebulized lidocaine within airflow of the CPAP device to patients of group A. Nebulized lidocaine solution 4 ml (1 ml/20 mg) diluted in 2-ml sterile isotonic saline was given through CPAP over 15 min immediately before FOB with applied pressure ranging from 7 to 9 cmH2O. CPAP used in the study was RESmart CPAP system (BMC medical Co. Ltd, Beijing, China).
FOB was done through nose with the patients in the semisetting position. FOB used in the study was PENTAX Medical Fiber Bronchoscopes FB-15V (New Jersey, USA).
Lidocaine spray 10% was given to the patients of group B through oropharynx and nose: approximately 6–8 puffs according to patients’ body weight as advised by the BTS guidelines (8.2 mg/kg) .
During the bronchoscopy in both studied groups, 2-ml lidocaine (20 mg/ml) was given by spray-as-you-go technique through the working channel of FOB when needed depending on patient tolerance. Vocal cords, trachea, and main carina were the commonest areas that needed lidocaine instillation.
Lidocaine administered during the FOB was determined as additional lidocaine doses, which were given at the discretion of the bronchoscopists and recorded for each patient as required.
Data entry, processing, and statistical analysis were carried out using SPSS program version 20. Quantitative variables were described as mean, SD, and range. Qualitative variables were described as number and percentage. Chi-square and Fisher’s exact tests were used for comparison.
The comparison between two independent groups with quantitative data was done by using independent t test. The confidence interval was set to 95% and the margin of error accepted was set to 5%. The P value less than 0.05 was considered significant.
| Results|| |
A total of 40 patients were enrolled in the current study, who were divided into two groups, with seven females and thirteen males in each group. The mean age and range were 54.10 and 20–77, respectively, in groups A 44.95 and 20–80, respectively, in group B. Mean patients’ weight was 77.45 and 80.25 in groups A and B, respectively.
There was a statistically significant difference between both groups regarding smoking as incidence of smoking was more in group A in comparison with group B, as shown in [Table 1]. There was a statistically significant difference between both groups regarding initial oxygen saturation, being higher in group B in comparison with group A, as shown in [Table 2].
|Table 1 Comparison between groups A and B regarding comorbid diseases, allergy to xylocaine, and smoking|
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|Table 2 Comparison between groups A and B regarding initial and lowest oxygen saturation, maximum oxygen flow, initial blood pressure and after fiberoptic bronchoscopy, initial heart rate and highest heart rate during fiberoptic bronchoscopy|
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Moreover, there was a highly statistically significant difference between both groups regarding initial blood pressure and initial heart rate, being higher in group A. Moreover, there was a statistically significant difference between both groups regarding initial oxygen saturation on 2 l/min, being higher in group B, as shown in [Table 2].
Interestingly, patients in group A had statistically significant difference between them and patients in group B, as the former group needed less additional doses of lidocaine to complete the procedure, whereas there is a nonsignificant difference between both groups regarding duration of FOB, as shown in [Table 3].
|Table 3 Comparison between groups A and B regarding duration of fiberoptic bronchoscopy and additional doses of xylocaine during fiberoptic bronchoscopy|
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There was a highly statistically significant difference between both groups regarding coughing during FOB, occurrence of gag reflex, and patients’ discomfort during FOB, being more commonly occurred in patients in group B in comparison with patients of group A. However, there was a nonsignificant difference between both groups regarding easiness of entry of FOB, as shown in [Table 4].
|Table 4 Comparison between groups A and B regarding entry of fiberoptic bronchoscopy, coughing during fiberoptic bronchoscopy, occurrence of gag reflex, and discomfort during fiberoptic bronchoscopy|
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| Discussion|| |
Data on the effectiveness of nebulized lignocaine during FOB is limited; some studies have small sample size, whereas others have used opioids, which can mask the effects of local anesthetic agent on cough suppression.
Local anesthesia for FOB can be done in different methods, such as lidocaine administration by tracheal injection, by nebulizer, or oropharyngeal spray of lidocaine. Alternatively, nebulization has the same anesthetic effects compared with oropharyngeal spray of lidocaine, but with a considerable lower blood serum lidocaine level. Moreover, patients prefer the nebulized route .
The use of lidocaine before FOB is recommended by guidelines to reduce gag reflex and coughing and to allow proper visualization of tracheobronchial tree ,.
The current study compared two different methods of lidocaine administration before FOB to monitor the need of additional doses of lidocaine, incidence of complications, and patients’ tolerability during FOB.
Our results showed that administration of nebulized lidocaine by CPAP led to reduced consumption of additional lidocaine doses with subsequent favorable safety profile owing to smaller dose of lidocaine given by nebulizer route compared with lidocaine administration via spray.
These results were matched with Dreher et al. , who studied the effect of nebulized lidocaine in comparison with conventional lidocaine administration via syringe through the working channel of FOB and consumption of sedative drugs on 30 patients in two groups; they found less additional doses of lidocaine and less sedative drug in the group of patients with nebulized lidocaine.
Furthermore, Foster and Hurewitz  revealed that lidocaine use by nebulization can limit the need for additional doses of lidocaine administered during FOB. Similarly, Gjonaj and his colleagues  studied different concentrations of nebulized lidocaine in children before FOB, and they showed that 50% of the examined children who received nebulized lidocaine at different concentrations did not need additional lidocaine doses.
Moreover, Müller et al. , in a study performed to assess consumption of lidocaine and sedative drugs (midazolam and propofol) among 60 patients who underwent FOB, showed the results coincided with our findings regarding additional doses of lidocaine, being lower in the group of nebulized lidocaine in comparison with conventional method.
Moreover, in a randomized double-blind study performed by Younus et al. , on 80 patients in two groups, comparing the effect of nebulized lidocaine with placebo group, the authors revealed that the use of nebulized lidocaine was associated with lower additional doses of lidocaine during FOB, which was matched with the results of our study.
In contrast to the results of the current study, Stolz et al.  revealed that the proof for use of nebulized lidocaine is contradictory. In a randomized controlled trial (150 patients) of nebulized 4% lidocaine in comparison with saline placebo, they declared no benefit to nebulized lidocaine regarding additional doses of lidocaine in patients received midazolam and hydrocodone. Actually, the group of patients with nebulized lidocaine received more additional doses of lidocaine than the placebo group.
The results of the current study revealed that there was a nonsignificant difference between the studied groups regarding duration of FOB, which was not matched with Gove et al. , who had demonstrated that nebulized lidocaine resulted in a shorter FOB duration than sprayed lidocaine in a study performed on 52 patients in two groups comparing nebulized lidocaine versus lidocaine spray.
Our results revealed that there was a nonsignificant difference between both studied groups regarding lowest SpO2 and maximum oxygen flow. In contrast to our results, Muller et al.  showed mean SpO2 was significantly higher in patients who received lidocaine by nebulizer compared with the group of patients who received lidocaine spray (P=0.0072). Moreover, they found the mean oxygen flow rate needed to maintain SpO2 at more than 95% was significantly higher in group of lidocaine spray versus nebulizer group. In the same content, Dreher et al.  revealed in their study higher mean SpO2 in the nebulizer group compared with the conventional group (P=0.0889), and the needed oxygen flow rate was lower in nebulizer group (3.53±2.15 l/min) when compared with conventional group (4.36±1.81 l/min) (P=0.0736).
Our results revealed that administration of nebulized lidocaine by CPAP was associated with less incidence of complications (coughing during FOB, occurrence of gag reflex, and patients’ discomfort during FOB). This is in agreement with Muller et al.  and younus et al. , who found that the complication rate during FOB was lower in the group of patients who received nebulized lidocaine in comparison with patients who received lidocaine spray.Inconsistent with our results, Stolz et al.  stated that the nebulized lidocaine administration before FOB did not markedly ameliorate patients comfort or decrease cough and was not efficient as local anesthesia in a study comparing nebulized lidocaine versus placebo saline in patients who received midazolam and hydrocodone.
Interestingly, all the previously mentioned research studies examined the effect of nebulized lidocaine versus lidocaine spray using 4 ml of 4% lidocaine solution (160 mg of lidocaine) or more by nebulizer to complete the FOB. This dose is subtherapeutic as guided by British Thoracic Society (8.2 mg/kg) . In our study, we used 4 ml of 2% nebulized lidocaine solution (80 mg of lidocaine) through CPAP. This small dose (80 mg of lidocaine) is half the usually used lidocaine dose by nebulizer in the aforementioned studies, with a resultant excellent outcomes regarding less need for additional doses of lidocaine, less incidence of complications, and more comfortable to patients during FOB.
To our knowledge, no studies have been done to assess the benefits of using nebulized lidocaine through CPAP, which seems to be superior to nebulized lidocaine alone owing to deep and rapid deposition of the anesthetic agent and decreased dose of lidocaine used, obviating its adverse effects.
In conclusion, administration of nebulized lidocaine through CPAP before FOB is associated with diminished use of lidocaine with less incidence of its adverse effects when compared with conventional method of lidocaine spray. Moreover, it has better patient acceptance than lidocaine spray owing to its unpleasant taste. So, it should be recommended for use before FOB on a wide scale.
Furthermore, bronchoscopists should calculate all lidocaine doses used at different sites during FOB and remain alert for symptoms of lidocaine toxicity, especially owing to variant lidocaine absorption and metabolism in different individuals.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]