|Year : 2016 | Volume
| Issue : 1 | Page : 11-15
To evaluate the use of ProSeal laryngeal mask airway in patients undergoing elective lower segment cesarean section under general anesthesia: A prospective randomized controlled study
Shalini Saini1, Sharmila Ahuja2, Kiran Guleria3
1 Department of Anaesthesiology, Pain and Palliative Care, BRAIRCH, All India Institute of Medical Sciences, New Delhi, India
2 Department of Anesthesiology and Critical Care, University College of Medical Sciences, New Delhi, India
3 Department of Gynecology and Obstetric, University College of Medical Sciences, New Delhi, India
|Date of Web Publication||22-Apr-2016|
Dr. Shalini Saini
H. No. 80, Ward No. 25, Mazid Mohalla, Bahadurgarh - 124 507, Haryana
Source of Support: None, Conflict of Interest: None
Background: Anaesthesia for caesarean section poses challenges unique to the obstetric patient due to changes in the airway and respiratory system. The choice of anaesthesia for caesarean section depends on various factors; however, general anaesthesia (GA) is necessary in certain situations. Supraglottic airway devices are an emerging method to secure the airway, especially in difficult situations. Of these devices, ProSeal laryngeal mask airway (PLMA) is designed to provide better protection of the airway. Use of PLMA has been reported to be successful as a rescue device in difficult intubation situations and in patients undergoing elective caesarean section without any complications. Hence, this prospective randomized study was designed to compare the use of PLMA with endotracheal tube (ETT) in patients undergoing elective lower segment caesarean section (LSCS).
Material and Methods: Patients undergoing LSCS under GA belonging to the American Society of Anaesthesiologists (ASA) grades 1 and 2 were included. Patients with history of less than 6 h of fasting, known/predicted difficult airway, obesity, gastro-esophageal reflux disease, and hypertensive disorder were excluded. A standard anaesthesia protocol was followed. All patients received aspiration prophylaxis. The airway was maintained with either PLMA or ETT. The parameters including ease of insertion, adequacy of ventilation, hemodynamic changes at insertion and removal of device, and incidence of regurgitation and aspiration were noted.
Statistical analysis: The data were analyzed by unpaired t-test, chi-square/Fisher's test.
Results: Findings of the study indicated that PLMA was easy to insert (20.67 ± 6.835 s) with comparable insertion time to ETT (18.33 ± 4.971, P = 0.136) and adequate ventilation was achieved with very minimal hemodynamic changes seen with PLMA as compared to ETT at the insertion and removal of devices (P = 0.01). There was no incidence of regurgitation with the use of PLMA. The incidence of postoperative sore throat was minimal (6.7%) with PLMA (P < 0.05).
Conclusion: PLMA appears to be a safe alternative to ETT for selected obstetric patients undergoing elective LSCS. A further study with a large group of patients is required to establish the safety of PLMA in obstetric patients.
Keywords: Cesarean section, general anesthesia (GA), ProSeal laryngeal mask airway (PLMA)
|How to cite this article:|
Saini S, Ahuja S, Guleria K. To evaluate the use of ProSeal laryngeal mask airway in patients undergoing elective lower segment cesarean section under general anesthesia: A prospective randomized controlled study. J Obstet Anaesth Crit Care 2016;6:11-5
|How to cite this URL:|
Saini S, Ahuja S, Guleria K. To evaluate the use of ProSeal laryngeal mask airway in patients undergoing elective lower segment cesarean section under general anesthesia: A prospective randomized controlled study. J Obstet Anaesth Crit Care [serial online] 2016 [cited 2019 Sep 23];6:11-5. Available from: http://www.joacc.com/text.asp?2016/6/1/11/181059
| Introduction|| |
Pregnancy is a physiological state with changes in various body systems. The challenges presented by a parturient requiring anesthesia or analgesia or both make the role of the obstetric anesthesiologist challenging. Anesthesia for cesarean section poses challenges unique to the obstetric patient due to the plethora of anatomical and physiological changes associated with pregnancy. Of these, changes in the airway and respiratory system are of primary concern to the anesthesiologist.  The choice of anesthesia for cesarean section depends on the indication for surgery, degree of urgency, maternal status, and desire of the patient. Although neuraxial anesthesia has been advocated for cesarean section, general anesthesia (GA) is necessary for the management of certain situations.  The challenges of GA include the possibility of difficult obstetric airway with failed intubation and risk of aspiration of gastric contents. The standard technique involves use of an endotracheal tube (ETT) by rapid sequence induction (RSI) method.  However, disadvantage of ETT is difficulty in placement due to various anatomical changes during pregnancy. Supraglottic airway devices are an emerging method to secure the airway in difficult situations. Of these devices, the ProSeal laryngeal mask airway (PLMA) is designed to provide better protection of the airway.  It has also been used as a rescue device in difficult intubation situations. ,, To date, there are limited studies to evaluate the use of PLMA in obstetric patients. A search of the literature revealed limited information comparing the use of PLMA to ETT in obstetric patients. Therefore, this study was planned with the objective of evaluating insertion characteristics, hemodynamic changes, and complications associated with use of PLMA versus ETT in obstetric patients undergoing elective LSCS.
After obtaining approval of the institutional ethical committee and written informed consent, 60 pregnant women scheduled for elective cesarean section under GA were enrolled in this prospective randomized study. Patients belonging to the American Society of Anesthesiologists (ASA) physical statuses I and II were included in the study. Patients with history of less than 6 h of fasting, known/predicted difficult airway, symptoms of pharyngeal reflux or gastroesophageal reflux disease, body mass index >30 kg/m 2 , and history of hypertensive disorder were excluded from the study. A standard anesthesia protocol was followed. Patients were administered intravenous ranitidine 50 mg and intravenous metoclopramide 10 mg 30 min prior to induction of anesthesia. In the operating room, the patient was placed in a supine position with lateral tilt for left uterine displacement. Routine monitoring including electrocardiogram (ECG), noninvasive blood pressure, temperature, and pulse oximetry was done. Patients were randomly assigned to two groups using computer-generated random numbers. Anesthesia was induced by RSI technique with intravenous thiopentone 5 mg/kg, and succhinylcholine 1.5 mg/kg. The airway was secured with either ETT or PLMA as per the randomized group. Secured airway was confirmed with auscultation for bilateral equal air entry and demonstration of a square wave capnograph. Anesthesia was maintained with 50% O 2 and 50% N 2 O in 1-1.5% isoflurane with vecuronium bromide (0.08 mg/kg) for neuromuscular blockade. Following delivery of the baby, oxytocin 20 units was given over 15-20 min to contract the uterus and morphine (0.1 mg/kg) was given for analgesia. Neuromuscular blockade was reversed with intravenous neostigmine (0.05 mg/kg) and intravenous glycopyrrolate (0.08 mg/kg) after skin closure. The airway device was then removed after the patient was awake and spontaneous breathing was achieved. The presence or absence of any clear or bile-stained fluid or blood was checked upon removal of the device. The insertion characteristics were defined as "easy" where the insertion at first attempt was within 30-40 s, "difficult" where more than one attempt was required, and "failed" where the airway could not be secured by the device even after two attempts. , Other parameters noted were time taken to secure the airway (defined as time from insertion of airway device to obtaining a square wave capnogram), adequacy of ventilation (yes/no) reflected by oxygen saturation (>98%), mean arterial pressure (MAP), and heart rate (HR) at the time of insertion of airway device, and then every 5 min for 10 min. Changes in MAP and HR of >20%, if any, were noted. In the PLMA group, additional observations included observing fluid in the airway/drain tube by intraoral examination and later, on removal of the mask, supracuff soiling was checked for any secretion. Soiling of the bowl of the cuff was tested for pH with litmus paper. A pH <2.5 was considered to be gastric aspirate. In case aspiration was suspected, an x-ray of the chest was planned postoperatively. Changes in hemodynamic parameters were also noted at the time of removal of either airway devices. Postoperatively, an incidence of sore throat was obtained on direct questioning of the patient after 24 h (yes/no), and any other airway complication was noted.
The data was analyzed using Statistical Package for the Social Sciences (SPSS, version 17.0; SPSS Inc., IBM, Chicago, IL, USA). The recorded parameters including age, weight, and time of insertion were evaluated by unpaired t-test. The intergroup comparison of rest of the parameters was done using chi-square test/Fisher's exact test. P value <0.05 was considered to be significant.
| Results|| |
The demographic profiles in terms of age and weight were comparable and are shown in [Table 1].
Indications for cesarean section
Indications for cesarean section are given in the following table [Table 2] and were comparable for both the groups.
The insertion was noted to be difficult in one patient in the PLMA group and was easy in the rest of the patients. In the ETT group, it was difficult to intubate the trachea in two patients (6.7%) while it was easy in the remaining patients. However, this difference was not found to be statistically significant (P = 1.00).
The time of insertion for the placement of both the devices was comparable. Patients were adequately ventilated with bilateral equal air entry and square wave capnography.
During tracheal intubation or PLMA placement, in the PLMA group, only one patient (3.2%) showed a rise in MAP of more than 20% while this was observed in all the patients in the ETT group. This difference was found to be statistically significant (P = 0.01). Only one patient (3.3%) in the PLMA group showed a rise in HR of more than 20% while it was seen in all the patients (100%) in the ETT group (P = 0.01). All patients in both the groups maintained saturation at and above 98%.
During extubation or device removal, in the PLMA group none of the patients showed any change in MAP of more than 20% while it was observed in all the patients in the ETT group (p = 0.01). All patients in the ETT group showed such a rise in HR while it was observed only in one patient (3.3%) in the PLMA group (P = 0.01).
Regurgitation was not observed in any of the patients in the PLMA group. At removal of PLMA, no solid particle was observed in the oral cavity except oral secretions. No soiling was observed on examination of the bowl of cuff. The pH of the secretions present in the bowl of the cuff was checked to rule out gastric secretion and this was noted to be in the range of 6-7. There were two patients in each group with minimal blood on the device. Since there was no case of regurgitation or suspected aspiration, x-ray was not required in any patient.
In the postoperative period, none of the patients complained of nausea or vomiting in either group. Two patients (6.7%) in the PLMA group complained of sore throat while 22 patients (73.3%) had sore throat in the ETT group (P = 0.00). Patients were followed up for 24 h for any other respiratory sequelae but none were present in either group.
| Discussion|| |
The obstetric anesthesiologist faces a unique situation while providing anesthesia for cesarean sections where they have to provide care for both the mother and the unborn baby. Although spinal anesthesia is the preferred technique for cesarean section, GA at times becomes imperative under certain circumstances due to its specific advantages. During GA, the airway of a patient is usually secured with ETT after RSI technique.  However, failed intubation remains a dreaded entity in this subset of patients due to various anatomical and physiological changes in pregnancy. Thus, the need for a safe and easy-to-use airway device has been recognized and supraglottic airway devices have been under consideration by researchers to fill in this void. PLMA has been used successfully by various anesthesiologists across the world when failed intubation was encountered during induction of anesthesia in obstetric patients. ,, These authors opined that PLMA was the preferred airway device as it offers several advantages such as protection against aspiration when correctly positioned and a gastric drain tube through which fluid and air can be suctioned out. The significance of PLMA can also be judged by its ability to gain a role in difficult airway algorithm.  Based on these reports, this study was planned to evaluate the role of PLMA as a safe airway device as compared to an ETT. Han et al.  prospectively studied the use of classic laryngeal mask airway (cLMA) in ASAI-II patients presenting for elective cesarean section who preferred GA. The cLMA provided an effective airway with no episode of hypoxia, aspiration, regurgitation, laryngospasm, bronchospasm, or gastric insufflation. There was no clear or bile-stained fluid following removal. However, absence of a gastric drain port may put the patient's safety at risk. More recently, in 2010 Halaseh et al.  reported the successful use of PLMA in 3,000 cases of ASAI-II patients undergoing elective cesarean section who preferred GA. PLMA was successfully inserted in all patients with no adverse event. These findings are in accordance with the results of our study where successful insertion of PLMA was achieved in all patients. Although there are studies comparing the efficacy of PLMA with ETT in the nonobstetric population, ,, a search of the literature failed to reveal studies comparing PLMA to ETT in obstetric patients undergoing cesarean section. It is imperative that the supraglottic device is inserted and placed correctly to achieve effective and quick control of the airway. Insertion characteristics were graded in accordance with earlier studies with supraglottic devices. , In this study, successful insertion at first attempt was possible in all patients except one in the PLMA group. This patient had modified Mallampati Grade of 1 at preoperative assessment with no other indicator of difficult placement except that the patient had a large tongue. The probable reason could be difficulty in manipulating PLMA through the oral cavity. In the ETT group, two patients were difficult to intubate with normal preoperative airway assessment and the reason was difficult layngoscopy in both the patients. Time taken to secure the airway was less than 30 s for both the groups, which is acceptable with RSI technique. Hemodynamic stability is another important issue in obstetric patients with comorbidities such as pregnancy-induced hypertension, eclampsia, antepartum hemorrhage, or cardiovascular diseases. Excessive rise or fall in MAP or HR in these groups of patients can lead to devastating consequences. Halaseh et al.  reported that none of their patients had fluctuations of blood pressure in excess of 25% on insertion of PLMA. In this study, hemodynamic changes remained insignificant with PLMA with insertion or removal. However, statistically significant changes were observed in the ETT group. Risk of aspiration still remains a concern in obstetric patients. However, the risk may have been overestimated as reported earlier by various authors, viz., Ezri et al., Kranz et al. and Olsson et al., ,, and Han et al.  reported that there was no evidence of clear, or bile-stained fluid on removal of cLMA in their patients. Halaseh et al.  in their series of 3,000 cases reported only one case of regurgitation but no evidence of aspiration was seen. In this study, no evidence of regurgitation or aspiration was observed in the PLMA group. Association of any postoperative morbidity in patients undergoing cesarean section has an implication on discharge of the patient as well as affects the patient psychologically by delaying an immediate bonding with the newborn. There was no complaint of nausea and vomiting in either group. The incidence of sore throat however, was high (73.3%) in the ETT group while it was significantly low (6.7%) in the PLMA group. This finding was in accordance with the findings of other authors. All patients made an uneventful recovery and no complication was noted in the postoperative period. From the findings of this preliminary study, it can be concluded that PLMA appears to be a safe alternative to ETT for obstetric patients undergoing elective LSCS. However, more prospective trials with a larger number of patients will be required to further validate these findings.
| Conclusions|| |
The findings of our study indicate that PLMA was easy to insert with an insertion time comparable to ETT and adequate ventilation was achieved with minimal hemodynamic change. No incidence of regurgitation was noted with use of PLMA. The incidence of sore throat was minimal as compared to ETT and all patients made an uneventful recovery, thereby suggesting that PLMA may be considered as a safe alternative to ETT in obstetric patients.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]