|Year : 2016 | Volume
| Issue : 1 | Page : 23-26
Effect of lidocaine instillation into endotracheal tube on intraocular pressure during extubation
Ahmed Hassanein MD 1, Josef Zekry1, Hosam Moharram2
1 Department of Anesthesiology, Minia University, Minia, Egypt
2 Department of Ophthalmology, Minia University, Minia, Egypt
|Date of Submission||09-Jun-2015|
|Date of Acceptance||11-Sep-2015|
|Date of Web Publication||17-Mar-2016|
Department of Anesthesiology, Minia University, Minia
Source of Support: None, Conflict of Interest: None
The aim of this study was to investigate the effect of lidocaine instillation into the endotracheal tube before extubation on intraocular pressure (IOP) and hemodynamics.
Patients and methods
A total of 60 patients of ASA physical status I and II between 18 and 40 years of age who were scheduled for elective unilateral ocular surgery (cataract, squint, or ptosis) were included in the study. Patients were randomly classified into two groups of 30 patients each: the lidocaine group, which received 1 mg/kg of lidocaine into the endotracheal tube before extubation, and the control group, which received saline into the endotracheal tube. IOP, systolic blood pressure, diastolic blood pressure, and heart rate were all measured before and after extubation.
There was a significant increase in IOP in the control group at 2, 5, and 10 min after extubation (P < 0.01) compared with baseline value (2 min before extubation). The elevation in IOP in the lidocaine group at 2 min was significantly lower than that in the control group (P < 0.05). The readings of IOP at 5 and 10 min were lower in the lignocaine group compared with the control group. Both groups showed a significant increase in systolic blood pressure and diastolic blood pressure after extubation compared with baseline (2 min before extubation), and the elevation in the lidocaine group was significantly lower than that in the control group (P = 0.0001).
Instillation of lidocaine into the endotracheal tube before extubation attenuates IOP after extubation.
Keywords: endotracheal tube, extubation, intraocular pressure, lidocaine
|How to cite this article:|
Hassanein A, Zekry J, Moharram H. Effect of lidocaine instillation into endotracheal tube on intraocular pressure during extubation
. Ain-Shams J Anaesthesiol 2016;9:23-6
|How to cite this URL:|
Hassanein A, Zekry J, Moharram H. Effect of lidocaine instillation into endotracheal tube on intraocular pressure during extubation
. Ain-Shams J Anaesthesiol [serial online] 2016 [cited 2022 Jul 5];9:23-6. Available from: http://www.asja.eg.net/text.asp?2016/9/1/23/178875
| Introduction|| |
Increase in intraocular pressure (IOP) may have few adverse effects in patients with healthy eyes but has dangerous effects on a diseased or an injured eye. Efforts must be taken to maintain intraocular tension at or below normal levels  . The stress response to tracheal intubation and extubation is associated with elevation of IOP mainly due to increased sympathetic stimulation , . The lower pharynx, epiglottis, and larynx contain numerous sensory receptors that respond to chemical, thermal, and mechanica1 stimuli. The mechanoreceptors are abundant, especially in the lower pharyngeal wall, epiglottis, and vocal cords. Stimulation of these mechanoreceptors during intubation or extubation can produce reflex motor responses such as cough and hiccup, and also reflex sympathetic stimulation and cardiovascular presser response  and release of catecholamines from the adrenal medulla into the circulation  . Such adrenergic outflow may cause vasoconstriction, tachycardia, and an increase in central venous pressure, which has a closer relationship with IOP compared with systemic pressure  . This can produce an acute increase in IOP by increasing the resistance to the outflow of aqueous humor in the trabecular meshwork between the anterior chamber and Schlemm's canal  .
Although intubation is a frequently adopted and well-studied procedure, especially when there is a problem in the airways, extubation of patients has not been considered a lot. Anesthesia specialists know that the short time period after extubation is very harmful and causes several events such as laryngospasm, aspiration, lack of perfect opening of airways, and lack of enough pulmonary rehabilitation and may result in marked increase in IOP and development of myocardial ischemia, especially in patients suffering from coronary artery disease  . Four urgent drugs, including epinephrine, lidocaine, naloxone, and atropine, are injected into the tracheal tube and are absorbed from the endotracheal membrane because of its abundant vessels ,,, . For avoidance of these complications, it is important to maintain IOP and cardiovascular condition at the end of general anesthesia. Therefore, the aim of this study was to determine the effect of lidocaine instillation into the endotracheal tube before extubation on IOP and hemodynamics.
| Patients and methods|| |
The study was conducted in Al-Minia University Hospital from April 2014 to February 2015. After approval from ethical committee and obtaining informed consent from patients, the study was carried out on 60 ASA grade I and II patients of either sex aged from 18 to 40 years taken up for elective ophthalmic surgeries (unilateral cataract, squint, or ptosis). Patients were divided into two equal groups (n = 30 each group) by means of simple random sampling. Patients with a history of glaucoma, suspected difficult airway, uncontrolled hypertension, diabetes mellitus, and obesity were excluded. Monitoring included ECG, heart rate (HR), pulse oximetry, end tidal carbon dioxide measurement, and noninvasive blood pressure using the monitor (Spacelabs monitor; model 90364, USA). An intravenous access was secured in the operation room and all patients received fentanyl 1.0 μg/kg intravenously, followed by induction of anesthesia with thiopentone sodium (5-7 mg/kg) until loss of eyelash reflex, and atracurium bromide 0.5 mg/kg was given for neuromuscular (NM) blockade. Lungs were mask ventilated for 3 min with 100% oxygen with isoflurane, and then the endotracheal tube was inserted with Macintosh laryngoscope and was fixed using adhesive tapes to the skin over the maxilla and the mandible. The patients were then connected to mechanical ventilation using positive intermittent mandatory ventilation. Patients in whom more than one attempt was required for correct placement of the tube were excluded from the study. Anesthesia was maintained using isoflurane and atracurium top ups for NM blockade. Near the end of surgery, we asked the surgeon to inform us 5 min before finishing the surgery, so as to instill 1.0 mg/kg lidocaine (2%) inside the endotracheal tube in lidocaine group patients. At the end of the surgery, isoflurane was stopped and the residual NM blockade was antagonized with neostigmine and atropine in appropriate dosages. Lidocaine spray (10%, 10 mg/dose) was sprayed two times (20 mg) inside the pharyngeal cavity 1 min before extubation in patients of the two groups. Extubation was performed when the patient was able to open his healthy eye in reply to verbal orders and after instillation of 0.5 mg/kg of lidocaine (2%) inside the endotracheal tube in lidocaine group patients. IOP was measured in the nonoperated eye (previously prepared with lubricant eye drops) 2 min before extubation, and subsequently three times at 2, 5, and 10 min after extubation using a Schiotz tonometer (The Diagnostic Company: Riester, Germany). After 2 min, the majority of patients can tolerate the use of the tonometer, but some patients may roll up their eyes and the ophthalmologist may have to gently retract the globe during IOP measurement. Hemodynamic parameters, which included HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP), were recorded simultaneously at the time of measuring IOP. These measurements were recorded by an assistant anesthetist who was blinded to the study groups.
On the basis of our pilot study on five patients in each group, a sample size of 30 patients per group was required to achieve a power of 80% with an α-error of 5%, to detect a change in IOP of 35% from baseline value after extubation in the control group versus an IOP of 6% in the lidocaine group.
For statistical analysis, Statistical Package for the Social Sciences (SPSS), version 16.0 (SPSS Inc., Chicago, Illinois, USA) software, was used. Continuous quantitative data were expressed as mean, SD, median, and range. Qualitative data were presented as number and proportion and analyzed using the χ2 -test or Fischer's exact test, as appropriate. The normality test was used to identify a distribution as not normal when the distribution was skewed. Nonparametric data were compared using the Mann-Whitney test to compare independent groups and using the Wilcoxon test to compare related groups. A P-value less than 0.05 was considered to be significant and a P-value less than 0.01 was considered highly significant.
| Results|| |
In our study, 60 young adult patients of ASA class I and II were divided into two equal groups (30 patients each) to study the effects of lignocaine instillation into the endotracheal tube before extubation on IOP and hemodynamics. The two study groups were comparable with respect to weight, age, sex, and surgical procedures [Table 1]. As regards hemodynamic changes [Table 2], both groups showed a significant increase in SBP at 2 and 5 min after extubation when compared with baseline (2 min before extubation), and the elevation in the lidocaine group at 2 min was significantly lower than that in the control group (P = 0.0001). Both groups showed a significant increase in DBP at 2 min after extubation when compared with baseline (2 min before extubation), and the elevation in the lidocaine group at 2 and 5 min was significantly lower than that in the control group (P = 0.002 and P = 0.003, respectively). HR showed nonsignificant differences neither within each group nor between the two groups.
|Table 2 Comparison of hemodynamic changes before and after tracheal extubation in the studied groups|
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As regards IOP changes [Table 3], there was a significant increase in the readings of IOP in the control group at 2, 5, and 10 min after extubation (P < 0.01) when compared with baseline value (2 min before extubation). IOP showed a significant increase in the lidocaine group at 2 min after extubation (P < 0.05). The elevation in IOP in the lidocaine group at 2 min was significantly lower than that in the control group (P < 0.05). The readings of IOP at 5 and 10 min were lower in the lidocaine group compared with the control group.
|Table 3 Comparison of intraocular pressure changes before and after tracheal extubation in the studied groups|
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| Discussion|| |
We must avoid the increase in ocular congestion or increase in IOP during intraocular surgery because of undesirable and possibly dangerous effects, such as expulsion of vitreous humor from the open eye. Therefore, an ideal anesthetic technique for intraocular surgery should produce a moderate reduction in IOP at near normal values and avoid marked fluctuations during surgery. We select the nonoperated eye during intraocular and extraocular surgery to execute our study. The main advantage of our result was the avoidance of rise in IOP during open eye surgery. In our study, we selected the young adult age (18-40 years), as airway reflexes are attenuated by age, and these reflexes are prominent in these middle ages than in old ages  . Intratracheal injection of lidocaine markedly attenuated the rise in IOP during the short period after extubation. All IOP measurements (2, 5, and 10 min) after extubation were significantly lower in the lidocaine than in the placebo group. We prefer instillation of lidocaine inside the tube to intravenous lidocaine, as in the study by Bidwaski and Stanely  , in which it was distinct that laryngospasm (severe and long reaction to laryngeal closure reflex) decreases in patients who received 2% lidocaine locally in the larynx region and above it, the same as patients who received intravenous lidocaine, with the difference that anesthesia and sleeping time does not increase in this state. Moreover, in the study by Gefke et al.  , an intratube injection of lidocaine did not cause an increase in dizziness and anesthesia time as that occurred with intravenous lidocaine. The hemodynamic responses in these times showed attenuation in the lidocaine group when compared with the placebo group. SBP was significantly lower at 2 min, and DBP was significantly lower at 2 and 5 min after extubation. HR readings were lower in the lidocaine than in the placebo group. In the study by Ebrahim, the IOP readings were elevated after intubation and extubation. The highest level of IOP was at first minute after intubation and extubation. The increase in IOP was greater after extubation than after intubation. The time passed after extubation until return of IOP to near baseline level was 10 min  . Moreover, similar observation was made by Pandya Malti and Agarwal  , who compared the effect of endotracheal tube versus laryngeal mask on IOP. They showed that IOP increased after extubation. The previous studies coincide with our finding that extubation stress elevates IOP. We tried to avoid or attenuate this rise in IOP after extubation by instilling lidocaine inside the endotracheal tube before extubation, and we found reduction and attenuation in this rise in the lidocaine group.
Bidwaski and Stanly examined the effects of lidocaine on blood pressure and HR in response to extubation. They injected 1.5 ml of lidocaine into the tracheal tube 3 to 5 min before extubation and then they instilled 1 ml (4%) of lidocaine just before extubation. They showed no increase in blood pressure and HR during 1-5 min after extubation  . Tavakkol et al.  studied the effect of lidocaine injection into the endotracheal tube on the incidence of cough and laryngospasm. In the test group 100 mg (5 ml) of lidocaine 2% and the same volume of placebo (normal saline) in the control group was injected into the endotracheal tube. The use of anesthetic drugs was discontinued 5-10 min before end of the surgery, and after ending the operation extubation was performed. The number of coughs and laryngospasm were assessed, recorded, and compared. The number of coughs was higher in the control group and the difference between the two groups was significant. We decided to test this abolishing effect of lidocaine on IOP as it increased during intubation and extubation. The pharyngeal use of lidocaine suppresses the supraglottic origin of stress reflexes, but endotracheal lidocaine instillation attenuates manly infraglottic reflexes during extubation.
| Conclusion|| |
Lidocaine instillation into the endotracheal tube before extubation can attenuate and prevent marked rise in IOP. It can be beneficial especially in open eye surgery.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]