|Year : 2015 | Volume
| Issue : 4 | Page : 511-515
I-gel versus cuffed endotracheal tube in elective cesarean section (double-blind randomized study)
Farahat I Ahmed MD , Ali M Hasan
Department of Anesthesia and Intensive Care, Faculty of Medicine, Zagazig University, Zagazig, Egypt
|Date of Submission||20-Oct-2014|
|Date of Acceptance||07-Apr-2015|
|Date of Web Publication||29-Dec-2015|
Farahat I Ahmed
41 El-Sahabah St., Hadyek Al-koppah, Cairo
Source of Support: None, Conflict of Interest: None
The role of supraglottic airway devices in general anesthesia for cesarean section (CS) has been controversial, although there is increasing evidence for their use in the difficult obstetric airway, especially in those with esophageal drains as the I-gel.
The aim of this study was to evaluate safety of the I-gel as an effective airway compared with the traditional use of cuffed endotracheal tube (ETT) in elective CS.
Materials and methods
Eighty parturient women, ASA I-II, scheduled for elective CS were randomly selected in this study. Under general anesthesia, the I-gel was compared with ETT as regards ease of insertion, insertion time, and success rate of insertion after first attempt, bucking at the end of surgery, and complications, which included trauma and laryngeal spasm. Other measurements included regurge and/or aspiration and air lack during ventilation using I-gel.
I-gel was significantly better compared with ETT in terms of the ease of insertion (P = 0.016), success rate after first attempt (P = 0.044), bucking before removal (P = 0.043), laryngeal spasm (P = 0.044), and postoperative complications, which included sore throat and trauma (P = 0.003).
I-gel is an easy, safe, and effective alternative airway device compared with the traditional use of cuffed ETT in elective CS
Keywords: elective cesarean section, endotracheal tube, I-gel
|How to cite this article:|
Ahmed FI, Hasan AM. I-gel versus cuffed endotracheal tube in elective cesarean section (double-blind randomized study). Ain-Shams J Anaesthesiol 2015;8:511-5
|How to cite this URL:|
Ahmed FI, Hasan AM. I-gel versus cuffed endotracheal tube in elective cesarean section (double-blind randomized study). Ain-Shams J Anaesthesiol [serial online] 2015 [cited 2019 Sep 21];8:511-5. Available from: http://www.asja.eg.net/text.asp?2015/8/4/511/172672
| Introduction|| |
It is known that the risk of aspiration in parturients is high because of the anatomical and physiological changes that occur during pregnancy. Therefore, high precautionary measures were followed during induction and recovery. One such precautionary measure is the use of rapid sequence induction (RSI) and endotracheal tube (ETT).
Most centers still use RSI in general anesthesia, which is not without its disadvantages, especially in the obstetric population in which there is an increased incidence of difficult and failed intubation  . The subsequent development of hypoxia leads to deleterious consequences for both the mother and the fetus, thus leading to guidelines that place an emphasis on oxygenation and ventilation over intubation. This is because it has been shown that multiple attempts at intubation may lead to increasing difficulty in ventilation and, ultimately, complete airway obstruction  .
The use of supraglottic airway devices (SADs) such as the classic laryngeal mask airway (cLMA) in cesarean section (CS) has traditionally been limited to failed intubation because cLMA was not designed to protect the lower airways from aspiration in this at-risk obstetric population. There was an evidence that the risk of aspiration is overestimated in the obstetric population  ; moreover, the incidence of aspiration with the cLMA for elective surgery is comparable to that with tracheal intubation, and the incidence of reflux is rare with cLMA even in at-risk patients  .
The I-gel is one of the second generation SADs [Figure 1] (Intersurgical, Wokingham, Berkshire, UK), which was introduced into clinical practice in 2007. It is made of a latex-free thermoplastic elastomer, soft gel-like substance  . This disposable device is designed to fit the perilaryngeal and hypopharyngeal structures without the use of an inflatable cuff, in contrast to other SADs  , and has the advantages of easier insertion, minimal tissue compression, and fewer positional changes after cuff inflation as in other SADs. Moreover, it was designed with a drainage tube, principally to separate the respiratory and gastrointestinal passages, thus minimizing the risk of aspiration. It also enables the creation of a greater seal pressure compared with the first generation SADs  .
To date, no randomized controlled trial has been performed comparing SADs with the ETT in elective CS. There have been case reports, case series, as well as cohort studies, on SADs being used in CS with great efficacy, but further studies are required to establish the safety profile of these devices  .
The current study was designed to evaluate one of these second generation SADs (I-gel) as an effective and safe airway in elective CS.
| Materials and methods|| |
After obtaining written consent from patients and after medical and ethical committee approval of Zagazig University Hospital, this prospective, randomized, double-blind study was completed. The study was carried out during six consecutive months, starting from February 2014. Eighty pregnant women, ASA physical status I and II, were enrolled for elective CS. Cases that had been operated under general anesthesia were randomly allocated into two groups (using a computer-generated random number assignment in sealed opaque envelopes): the I-gel group (group-I = 40) and the cuffed endotracheal group (group-T = 40). Each group included 40 cases. Airway management was carried out using either the I-gel (group-I) or cuffed ETT (group-T). All cases were made to fast for at least 6 h before the operation. Exclusion criteria included morbid obesity (BMI>40), known esophageal reflux, and compromised or abnormal airway (e.g. mouth opening<2.5 cm). All patients received premedication of ranitidine 50 mg and metoclopramide 10 mg intravenously 30 min before surgery.
Standard monitoring was applied, which included ECG, noninvasive blood pressure, and oximetry. Induction of anesthesia was carried out by means of RSI technique using intravenous thiopental 7 mg/kg, followed by rocuronium 0.8 mg/kg. Gentle mask ventilation with a tidal volume of 5 ml/kg and cricoid pressure for a time less than 1 min was applied until adequate relaxation. Thereafter, cricoid pressure was released after insertion of either I-gel or ETT. Correct placement of the device was confirmed by observation of proper chest expansion, square shape of end-tidal CO 2 waveform, and absence of audible leak sounds.
In group-I, the I-gel device was carefully selected according to the manufacturer's recommendations. For patients weighing 50-90 kg, size 4 was used, and for patients weighing above 90 kg size 5 was appropriate. Proper preparation in the form of lubrication with a water-soluble lubricant was carried out. The I-gel was inserted by continuous introduction into the mouth against the hard palate until resistance was felt, as recommended by the manufacturer. In case the airway and ventilation were not established properly, gentle pushing, pulling, head extension, jaw thrust, or neck flexion manipulations were tried before considering failed attempt. Gastric tube was lubricated and inserted down the gastric drainage port of the I-gel.
The lungs were ventilated using volume-controlled ventilation with a tidal volume of 6-8 ml/kg, provided the peak airway pressure did not exceed 35 cmH 2 O, respiratory rate was 12 breaths/min, and I/E ratio was 1 : 3 using Penlon ventilator. Side stream end-tidal CO 2 monitoring was mounted. Maintenance of anesthesia was carried out with isoflurane/oxygen mixture and rocuronium titration if needed. All cases were given nalbuphine 0.15 mg/kg intravenous after delivery of the baby.
Data recorded included weight, insertion time (from the time of insertion until auscultation of adequate lung ventilation), ease of insertion (which was graded into four grades as follows: 1 = very easy, 2 = easy, 3 = difficult, and 4 = very difficult)  , and success rate after first attempt of insertion, which is considered successful if there is adequate lung ventilation without air leak. The data recorded also included peak airway pressure before delivery of the baby, auscultation of audible air leakage, regurge of gastric contents, bucking, and laryngeal spasm at removal of the device. Complications occurring during insertion and removal were noted for each patient, such as airway trauma, sore throat, coughing, gastric distension (by auscultation of epigastrium), and hoarseness of voice, and were evaluated after recovery.
Data were statistically described in terms of mean ± SD, median, frequencies (number of cases), and percentages when appropriate. Data were entered and analyzed using Microsoft Excel software. Data were then imported into Statistical Package for the Social Sciences ((SPSS Inc., Chicago, IL, USA) (Statistical Package for the Social Sciences) software for analysis. On the basis of the type of data, the following tests were used to test differences for significance. Differences between frequencies (qualitative variables) in groups were compared using the c2 -test. Differences between means (quantitative variables) in two parametric groups were compared using Student's t-test. A P value was set at less than 0.05 for significant results and at less than 0.001 for high significant result.
| Results|| |
As shown in [Table 1], it was noted that there was a statistically significant difference between the I-gel and ETT, where the insertion time was less in group-I compared with group-T. Ease of insertion and success rate after first attempt were better in I-gel (group-I) than in tracheal tube (group-T) (P < 0.05). In group-T, there were four cases of difficult intubation; of which, three of them needed intubating stylet and/or external laryngeal manipulation for successful intubation; however, in one, the intubation was failed after two trials and the I-gel was inserted successfully. Only one case (2.5%) of audible air leak after I-gel insertion, which was corrected by pushing and gentle twisting of the device, was met. Otherwise, there was no leak even during fundal pressure during which the airway pressure exceeded the leak pressure. However, the peak airway pressure before delivery of the fetus was significantly higher in group-I compared with group-T, but clinically insignificant as the peak airway pressure was still less than 35 cmH 2 O. Moreover, no regurge, airway trauma, bucking laryngeal spasm, sore throat, dysphagia, or hoarseness were noted postoperatively in I-gel cases.
|Table 1 Comparison between group-I and group-T as regards various parameters|
Click here to view
In group-T, bucking occurred in eight (20%) cases, laryngeal spasm in four (10%) cases, and postoperative mild temporary self-limited complications such as coughing and sore throat were noted.
| Discussion|| |
The role of SADs in elective CS for low-risk pregnancies has been debated at length. SADs have characteristics that favor its use in elective surgery, such as similar risk of aspiration between patients who are ventilated with SADs and patients who are intubated with the ETT in elective surgery, ease of insertion, reduced orodental trauma, lower incidence of sore throat, and possibly higher patient satisfaction scores; these studies have also demonstrated SADs to be efficacious  .
This randomized study that compared I-gel with ETT in general anesthesia in elective CS showed the efficacy and safety of the I-gel. In I-gel, the insertion was better compared with cuffed ETT. Moreover, there was better seal pressure and no leak, with a tidal volume of 6-8 ml/kg and airway pressure range 25-30 cmH 2 O, which increased with fundal pressure.
No complications were noted with I-gel in terms of gastric distension, regurge, and aspiration despite the increased gastric pressure, which may exceed 65 mmHg during fundal pressure  . Moreover, there were no cases of orodental trauma in which blood was seen on the device on removal. Only four (10%) cases suffered sore throat that was mild and did not need treatment.
Studies that were conducted on CS cases did not use the I-gel but used other SADs. One such study was conducted by Han and colleagues, who investigated the use of the cLMA for the ventilation of 1067 selected women undergoing general anesthesia for elective CS. An effective airway was achieved in 1060 (99%) patients: in 1051 (98%) patients at the first attempt and in nine (1%) patients at the second or third attempt. Air leakage or partial airway obstruction occurred in 22 (2.1%) patients, and seven (0.7%) required intubation. There were no episodes of hypoxia (SpO 2 < 90%), aspiration, regurgitation, laryngospasm, bronchospasm, or gastric insufflation. This study concluded that the cLMA is effective and probably safe for elective CS in healthy, selected patients when managed by experienced cLMA users  .
In addition, Halaseh and colleagues studied 3000 parturients undergoing general anesthesia for CS, with the use of the ProSeal laryngeal mask airway (PLMA). This study showed that the insertion of PLMA was successful in all patients, although eight (0.3%) required reinsertion with PLMA of a larger size to prevent excessive leakage. The blood pressure and heart rate remained within 25% of the baseline in all cases. However, there was one case of regurgitation of gastric contents after insertion of the PLMA and gastric tube, which occurred during application of fundal pressure at the delivery of the neonate. This problem highlights the need to limit fundal pressure if SADs are utilized. There was no evidence of aspiration from the episode. The study also found a low incidence of sore throat and dysphagia (0.3%) compared with tracheal intubation (>25%)  .
Yao and colleagues conducted an observational study involving 700 parturients, due for both elective (fasting time more than 6 h) as well as urgent CS (fasting time more than 4 h), who were at low risk of aspiration. In their study, all attempts at insertion of supreme laryngeal mask airway were successful, with 686 (98%) inserted on the first attempt and with a time to effective airway of 19.5 s. They were able to ventilate the patients with a good seal and there was no evidence of aspiration. Eighteen (2.6%) cases had blood on the supreme laryngeal mask airway on removal and 24 (3.4%) had sore throat. Results were similar in both elective and urgent cases  .
Moreover, there were other multiple studies for the use of I-gel compared with other SADs and also ETT in non-CS. Kini and colleagues compared I-gel and PLMA, especially as regards time taken for insertion, number of attempts, effectiveness of seal, and occurrence of postoperative sore throat apart from other parameters of their efficacy. They concluded that ease and shorter times to successful insertion were observed with I-gel. PLMA had higher airway leak pressure, which may be better suited for controlled ventilation. Both devices are comparable with respect to fiberoptic view of larynx, ease of Ryle's tube insertion, and incidence of sore throat  .
Moreover, another study had reported the efficacy of I-gel in protection of the lower airways from aspiration when there are large amounts of gastric contents  . Moreover, others have shown that the insertion of the I-gel was significantly easier when compared with insertion of other SADs  . In addition, the fiberoptic view was better in I-gel than in PLMA in pediatric anesthesia  .
As regards the leak pressure, one study reported that the average leak pressure for I-gel was 28 (20-35) cmH 2 O with both auscultation and manometer stabilization methods  , but another concluded that airway leak pressure for I-gel was 25-27 cmH 2 O using the same methods  . Ibrahim et al.  tested the I-gel as an effective airway in conventional ETT. They suggested that I-gel can be used as an alternative device to ETT during volume controlled ventilation in laparoscopic cholecystectomy, provided the peak pressure does not exceed leak pressure.
The airway sealing pressure was tested using one of the following four methods: detection of audible noise by listening over the mouth: detection of exhaled carbon dioxide by placing a gas sampling line for the capnograph inside the mouth; detection of a steady value airway pressure while occluding the expiratory valve of the circle system; and detection of an audible noise using a stethoscope placed just lateral to the thyroid cartilage  .
The effective airway leak pressure is essential especially when using SADs in patients with increased respiratory resistance, chronic obstructive pulmonary disease, cardiopulmonary resuscitation, and obese patients.
| Conclusion|| |
From the previous studies and our randomized study, we can conclude that the I-gel is one of the SADs that is more appropriate in cases where aspiration is a concern because of their greater seal pressure and the advantage of allowing for suctioning of gastric contents. Therefore, it can be used safely in elective CS. Moreover, it has the advantages of rapid, easy, and successful insertion. In addition, there are little hemodynamic changes, high patient satisfaction, and it is nontraumatizing during insertion. This will open the door for more studies for its routine use in elective CS cases that preferred general anesthesia instead of ETT.
| Acknowledgements|| |
Conflicts of interest
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