|Year : 2018 | Volume
| Issue : 2 | Page : 386-391
Comparative evaluation of sevoflurane, propofol, and combination of sevoflurane and propofol on insertion characteristics of reusable classic laryngeal mask airway
Yamini Gupta1, Tek Chand Kriplani2, Vansh Priya3
1 Department of Cardiac Anaesthesia, L. P. S. Institute of Cardiology, GSVM Medical College, Kanpur, India
2 Department of Anaesthesia and Critical Care, NSCB Medical College, Jabalpur, Madhya Pradesh, India
3 Department of Anaesthesia, T. S. Misra Medical College, Lucknow, Uttar Pradesh, India
|Date of Web Publication||14-Jun-2018|
Dr. Vansh Priya
3/279, Vishwas Khand, Gomti Nagar, Lucknow - 226 010, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background and Aim: Adequate depth of anaesthesia is needed for successful placement LMA.under lighter plane of anaesthesia inadequate mouth opening,coughing,body movements can lead to rejection of LMA and may be associated with breath holding and bronchospasm. Use of propofol in doses which allow adequqate jaw relaxation and prevent patient reaction to LMA commonly results in hypotension and prolonged apnoea.Apart from minimal respiratory irritant properties sevoflurane as compared to propofol has the advantage of providing better hemodynamic stability and a smoother transition to the maintainance phase without a period of apnea.However sevoflurane is associated with delayed jaw relaxation and a longer time for the insertion of the LMA.Our hypothesis is that induction of anaesthesia with the combination of sevoflurane and small dose of propofol may optimize the insertion conditions of LMA and decrease the side effects of individual drugs. Methods: 90 patients aged 18-65 yrs ASA physical status I and II undergoing elective procedures were randomly allocated into 3 groups of 30 patients each. No patient had been given any premedication.Patients in group P were induced with iv inj propofol 3 mg/kg. Patients in group S an SP were induced with tidal volume breathing induction technique using sevoflurane 8% along withN20: 02: 67:33 @ 6L/MIN In addition, in group SP after loss of eye lash reflex patients were given IV propofol 1.5 mg/kg.An independent observer assessed insertion characteristics. Results: our results showed that induction of anesthesia using the combination of sevoflurane and propofol resulted in the most frequent successful LMA insertion at first attempt as compared with induction of anesthesia with either sevoflurane or propofol alone.
Keywords: Classic laryngeal mask airway, propofol, sevoflurane
|How to cite this article:|
Gupta Y, Kriplani TC, Priya V. Comparative evaluation of sevoflurane, propofol, and combination of sevoflurane and propofol on insertion characteristics of reusable classic laryngeal mask airway. Anesth Essays Res 2018;12:386-91
|How to cite this URL:|
Gupta Y, Kriplani TC, Priya V. Comparative evaluation of sevoflurane, propofol, and combination of sevoflurane and propofol on insertion characteristics of reusable classic laryngeal mask airway. Anesth Essays Res [serial online] 2018 [cited 2020 Apr 7];12:386-91. Available from: http://www.aeronline.org/text.asp?2018/12/2/386/228950
| Introduction|| |
Propofol is a preferred induction agent for laryngeal mask airway (LMA) insertion due to its propensity of suppressing oropharyngeal and cough reflexes. Adequate jaw relaxation is an absolute prerequisite for successful LMA placement. However, use of propofol in dosages (usually >2.5 mg/kg) required for adequate jaw relaxation and adequate depth of anesthesia for LMA insertion may result in arterial hypotension, apnea, and collapse of upper airways.,,,
Sevoflurane is a nonpungent inhalation anesthetic agent which can be used as an induction agent. Its nonpungent odor with minimal respiratory irritant properties makes it suitable for inhalation induction of anesthesia and insertion of the LMA while preserving spontaneous ventilation. Sevoflurane as compared to propofol has the advantage of providing better hemodynamic stability and a smoother transition to the maintenance phase without a period of apnea. However, sevoflurane is associated with delayed jaw relaxation and a longer time for the insertion of the LMA., This study was based on our hypothesis that induction of anesthesia with the combination of sevoflurane and small dose of propofol may optimize the insertion conditions of LMA while reducing the incidence of associated side effects of individual drugs.
In this prospective randomized study, a comparative evaluation of anesthesia induction with combination of sevoflurane and propofol, sevoflurane alone, or propofol alone on insertion characteristics of reusable silicone classic LMA (CLMA) (LMA North America, Inc.) in adult patients undergoing elective surgery. We also compared the incidence of side effects such as gagging, coughing, and laryngospasm and the incidence of duration of apnea.
| Patients and Methods|| |
After institutional ethics committee approval and written informed consent from patients, ninety adult American Society of Anesthesiologists Physical Status I–II patients aged 18–65 years undergoing elective general surgery, orthopedics, and plastic or gynecologic procedures were studied over a period of 1 year.
- Patients with a history of difficult intubation or anticipated difficult intubation
- Allergy or sensitivity to volatile anesthetics or to propofol
- Body mass index >1.5 times normal
- Heavy smokers (>20 cigarettes/day)
- Patients with diabetes, hypertension, cardiovascular disease, ischemic heart disease, liver disease, and renal impairment.
Routine preoperative preparation was followed. In the morning of the surgery, patients were examined and blood pressure, pulse rate, and respiratory rate were recorded for further comparison.
The patients were then randomly allocated to the following three groups by computer-generated slips.
- Group S – Patients were induced with circuit primed with sevoflurane 8%, nitrous oxide and oxygen (67%:33%) at fresh gas flow (FGF) rate 8 L/min by tidal volume breathing (TVB) technique
- Group SP – Patients were induced with circuit primed with sevoflurane 8%, nitrous oxide and oxygen (67%:33%) at FGF 8 L/min by TVB technique and injection intravenous (IV) propofol (1.5 mg/kg)
- Group P – Patients were induced with IV injection propofol only (3 mg/kg).
All the CLMA insertion were performed by the same anesthesia consultant well versed with LMA placement (LMA classic >1000 procedures). All the patients in Group S and Group SP were induced with inhalation anesthetic mixture comprising sevoflurane 8% and N2O:O267%:33% and FGF at 8 L/min employing TVB technique through Bain's circuit. The patients were instructed to continue breathing normally through face mask during induction of anesthesia. The start of the induction was taken as the time at which patient starts breathing from the circuit (time zero). Patients were further instructed to open their eyes every 10 s. Failure to do so was taken as loss of consciousness, further confirmed by testing for loss of eyelash reflex. In Group S, 90 s into inhalation induction, the ease of mouth opening was assessed as adequate or inadequate. If mouth opening was inadequate, attempts were made every 30 s up to a maximum of 4. In between attempts, depth of anesthesia was maintained with sevoflurane at 8% in 67%:33% ratio of N2O-O2 at 8 L/min.
Patients in Group SP were induced with TVB technique similar to that used in Group S. Time to loss of consciousness was determined as it has been for Group S. In addition, at the loss of eyelash reflex, the patients were given IV propofol (1.5 mg/kg) over 15 s. Thirty seconds after completion of propofol induction, ease of mouth opening was assessed. If inadequate, attempt every 30 s up to a maximum of four were made, each time preceded by IV propofol bolus of 0.5 mg/kg. In between attempts, depth of anesthesia was maintained with sevoflurane at 8% in 67%:33% ratio of N2O-O2 at 8 L/min.
Patients in Group P were induced with IV propofol 3 mg/kg given over 30 s. Midway through induction at 15 s, the patients were asked if they were feeling any pain from the injection. Loss of consciousness was assessed as for Group S and Group SP. Time to loss of consciousness was calculated from the time of start of injection of propofol until loss of eyelash reflex and inability to open eyes upon verbal command. Thirty seconds after the completion of propofol induction, i.e., 60 s after the start of propofol injection, ease of mouth opening was assessed. If inadequate, attempts every 30 s up to a maximum of four were made, each time preceded by IV propofol bolus of 0.5 mg/kg. In case of apnea during induction, ventilation was assisted manually between LMA insertion attempts. Additional propofol was given if there was any adverse response such as movement, gagging, coughing, or laryngospasm. Noninvasive arterial blood pressure, oxygen saturation, and heart rate were recorded every minute for 5 min. An independent observer recorded:
- Time taken to loss of eyelash reflex
- Time taken to jaw relaxation
- Time taken to completion of successful insertion of LMA
- Successful insertion of LMA at first attempt
- Apnea duration
- Incidence of apnea.
The presence of complications related to anesthetic induction was noted namely:
- Excitatory movements during induction
- Hiccup and insertion of the LMA were noted.
The presence of complications during LMA insertion was noted namely:
Subsequent to CLMA placement, IV vecuronium was administered and anesthesia was maintained on sevoflurane and intermittent IV bolus of fentanyl.
Once fully awake, the patients were asked by a blinded investigator for induction experience, sore throat, nausea, and vomiting.
Postoperative assessment instead of post operative interview:
- Presence of sore throat (yes or no)
- Pleasant induction (yes or no)
- Repeat same technique (yes or no)
- Postoperative nausea and vomiting (PONV) (yes or no).
The sample size was calculated after a pilot study of 20 patients and was based on a difference of 20% between the groups for insertion characteristics for a type 1 error of 0.05 and a power of 0.8. Data analysis was done with the help of SPSS Software Version 15 (IBM, Chicago, USA) and Sigma Plot Version 12 12 (windows 8, Richmond, Washington, USA). Quantitative data were presented with the help of mean and standard deviation. Comparison among the study groups was done with the help of unpaired t-test and Mann–Whitney test as per the results of normality test. Qualitative data were presented with the help of frequency and percentage table. Association among the study groups was assessed with the help of Chi-square test. P< 0.05 was considered statistically significant.
| Results|| |
All the three groups were comparable with respect to age, sex, and weight [Table 1]. The induction endpoint (loss of eyelash reflex) was 47.63 ± 6 s, 35.67 ± 5.85 s, and 44.93 ± 8.737 s in Group SP, Group P, and Group S, respectively. The difference between time taken for loss of eyelash reflex between the three groups was found to be statistically insignificant (P > 0.05) [Table 2]. In all the groups, hemodynamic parameters were comparable at baseline and thereafter every 60 s during induction and insertion of CLMA [Table 3] and [Table 4].
|Table 1: The age- and sex-wise distribution of the cases in studied groups|
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|Table 3: Mean heart rate in various groups after start of induction including laryngeal mask airway insertion (/min)|
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|Table 4: Mean blood pressure (mmHg) in various groups after start of induction including laryngeal mask airway insertion (/min)|
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Time taken for jaw relaxation was observed to be shortest in Group P (68.67 ± 17.2 s) which was statistically significant when compared to Group SP (96.73 ± 7.10) and Group S (145.93 ± 53.075 s) [Table 5]. Similarly, time to CLMA insertion was shortest in Group P (93.50 ± 31.92 s) which was statistically significant when compared to Group SP (115.73 ± 10.863 s) and Group S (202.7 ± 20.405 s) [Table 6].
First pass success rate of CLMA insertion was found to be highest in Group SP (90%), which was statistically significant when compared to Group P (56.7%) and Group S (13%) [Table 7].
|Table 7: Incidence of insertion of laryngeal mask airway at first attempt|
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There was no significant difference between incidence of laryngospasm and cough during induction between the three groups. Group P was found to have the highest incidence of apnea during induction (73.3%) followed by Group SP (16.7%) and least in Group S (6.71%). Duration of apnea was found to be longest in Group P (178.23 ± 42.29 s), followed by Group SP (40.16 ± 7.05 s) and least in Group S (41.33 ± 10.07 s). No statistically significant difference was found between the three groups with respect to patient acceptance to induction technique.
83.3% in Group SP, 76.7% in Group P, and 83.3% in Group S remarked their respective induction technique as pleasant [Table 8].
93.3% patients in Group SP, 76.67% in Group P, and 73.3% patients in Group S preferred repeating the same induction technique [Table 9].
73.43% in Group SP, 80% patients in Group P, and Group S had postoperative sore throat.
Incidence of PONV was highest in Group S (33.3%), followed by Group SP (30%) and least in Group P (10%).
| Discussion|| |
Majority of studies evaluating LMA insertion characteristics using sevoflurane or propofol have employed the use of CLMA and in the pediatric population. Limited evidence in the form of literature is available regarding CLMA insertion characteristics using sevoflurane or propofol in adults, thereby making this study unique. Chavan et al. in their study on sixty patients compared CLMA insertion characteristics using sevoflurane or propofol. Insertion time in this study in sevoflurane group was significantly shorter when compared to our study, albeit the method of induction was similar. Reduced insertion time in sevoflurane group in this study could be attributed to the use of vital capacity breath (VCB) during inhalation induction as compared to TVB method of inhalation induction in our study. The study also concluded that the first pass success rate of CLMA insertion was high and comparable in both sevoflurane and propofol group which is in marked contrast to our study.
Shao and Zhang in their study on 90 elderly patients evaluated CLMA insertion characteristics by comparing IV induction by propofol with inhalation induction using 8% sevoflurane VCB technique or using 8% sevoflurane TVB technique. Their observation that inhalation induction using 8% sevoflurane TVB technique provides a stable hemodynamic profile, a prolonged CLMA insertion time concurs well with our study. Further incidence of apnea was more in propofol group when compared to sevoflurane groups which further cement our observation.
Siddik-Sayyid et al. on comparing combination of sevoflurane (8% by VCB induction technique) and IV propofol (1.5 mg/kg) with sevoflurane or propofol (2.5 mg/kg) in terms of insertion characteristics of CLMA, observed results similar to our study.
Insertion characteristics may be influenced by both induction agent, method of induction, and type of LMA. Therefore, “ease of insertion” is a highly subjective, operator-dependent assessment and thus subject to bias. Consequently, the first insertion success rate and time taken to insert the LMA are considered as surrogate markers of “ease of insertion.”
Molloy et al. observed that anesthetic induction with sevoflurane requires longer time to jaw relaxation and even causes jaw tightness. Dwivedi et al. also reported jaw tightness after sevoflurane anesthetic induction, which resulted in failure to insert the LMA in several patients. However, in our study, LMA was successfully inserted in all patients.
In a meta-analysis comparing anesthetic induction between sevoflurane and propofol, Joo and Perks found that sevoflurane induction was associated with more patient dissatisfaction and increased PONV which is akin to our observation.
Smith and Thwaites compared target-controlled infusion of propofol with large initial concentration of sevoflurane for LMA insertion. Inhalation induction was associated with more PONV (30% versus 3%) with delayed discharge; in our study, patients in Group S and Group SP had more frequent PONV than patients in Group P. This could be attributed to antiemetic property of propofol, initial large concentration of sevoflurane, or swallowing of air and gases during inhalation induction.
| Conclusion|| |
In accordance with other similar studies, propofol owing to its quick onset is an excellent agent for LMA insertion. Rapidity and ease of insertion it affords are better than sevoflurane or its combination with propofol. Propofol was also associated with reduced incidence of nausea and vomiting. However, the incidence and duration of apnea appear to be much more longer with propofol induction.
Induction with sevoflurane was observed to be more time-consuming as compared to propofol and was associated with an increased number of attempts. Its use was also associated with increased incidence of nausea and vomiting.
The combination of sevoflurane and propofol appears to be a better choice as it confers advantages of either agent. Although time required for induction is considerably more with combination, the first attempt success rate is significantly more when compared to either agent alone. The combination is associated with reduced incidence of apnea although it is associated with nausea and vomiting. Our study did not observe any statistically significant variation in hemodynamic variables among the three groups.
We did not measure the depth of anesthesia and this stands out as a limitation of our study as we employed two different methods of induction. Other limitation of this study is that we did not evaluate the three groups in terms of cost incurred.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9]