|Year : 2016 | Volume
| Issue : 1 | Page : 1-2
Routine use of laryngeal mask airway for cesarean section: Is it time to reconsider?
Anjan Trikha, Dalim Kumar Baidya
Department of Anaesthesiology, Pain Medicine and Critical Care, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||22-Apr-2016|
Dr. Dalim Kumar Baidya
Department of Anaesthesiology, Pain Medicine and Critical Care, All India Institute of Medical Sciences, Room No - 5011, 5th Floor, Teaching Block, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Trikha A, Baidya DK. Routine use of laryngeal mask airway for cesarean section: Is it time to reconsider?. J Obstet Anaesth Crit Care 2016;6:1-2
|How to cite this URL:|
Trikha A, Baidya DK. Routine use of laryngeal mask airway for cesarean section: Is it time to reconsider?. J Obstet Anaesth Crit Care [serial online] 2016 [cited 2019 Dec 10];6:1-2. Available from: http://www.joacc.com/text.asp?2016/6/1/1/181053
The unique physiology of airway in pregnancy and labor including increased intra-abdominal pressure, delayed gastric emptying, and reduced lower esophageal sphincter pressure effectively amounting to a full stomach imparts a strong risk of regurgitation and aspiration during general anesthesia, when administered for a cesarean section. Although, neuraxial anesthesia is considered to be the gold standard technique for such cases; general endotracheal anesthesia is still recommended for category 1 cesarean section for its rapidity of onset,  though maternal morbidity from failed intubation and aspiration remains the biggest concern with general anesthesia. The use of laryngeal mask airway (LMA) for failed intubation is considered acceptable in all difficult airway situations including cesarean sections; and with the introduction of second generation LMAs, administration of general anesthesia with a LMA has become the gadget of choice in such scenarios. , Of late, enthusiastic use of LMAs in elective cesarean sections has been reported in large patient groups and these authors have produced acceptable results as far as their efficacy and safety is concerned. ,, In the current issue, one of the first randomized controlled trials comparing Proseal LMA (PLMA) with endotracheal tube (ETT) for elective cesarean sections in 60 parturients has been published.  The authors have concluded that "PLMA may be considered a safe alternative to endotracheal tube in obstetric patients." The point that needs to be stressed is that PLMA is an alternative to endotracheal intubation in this subgroup of patients. But is a device that is a supposedly safe alternative be recommended as a part of a standard technique?
There are several advantages that a LMA provides over an ETT that have led to its popularity in elective and emergency anesthesia practice. Foremost of these are - Less expertise required for insertion with an easy learning curve and less time required for its insertion. This has led to it being accepted as the most useful rescue device in failed intubation scenarios. Moreover, it is associated with lesser incidence of postextubation sore throat, hoarse voice, laryngospasm, and coughing as compared to an ETT.  However, the safety profile of this device needs to be carefully evaluated and considered before its use may be made more liberal in special "at-risk" populations such as term parturients. Few critical questions remain unanswered - Should the LMA be regularly used for all elective cesarean sections or only in cases of failed intubation? If used electively, what should be the selection criteria of such parturients? Most importantly, does its use provide any worthwhile benefit over endotracheal intubation other than decreased incidence of sore throat. It is common knowledge that the possibility of aspiration remains higher when an LMA is being used as compared to an ETT in an event of regurgitation.
Han et al. used classic LMA in a series of 1,067 carefully selected parturients and found no incidence of hypoxia, regurgitation, or aspiration. Effective airway was obtained in the first attempt in 99% patients and only seven patients (0.7%) required intubation.  This would imply that in 10 parturients, the placement of LMA was difficult and a removal of the device was required with a repeat insertion. Further, in their series, seven patients required intubation which itself is a very high number. In case only an ETT based anesthesia was planned, all this could have been prevented.
Halaseh et al. evaluated PLMA for cesarean section in 3,000 mothers over a period of 6 years from 2004 to 2009 and observed only one case of regurgitation. Effective airway in the first attempt was established in 99.7% patients and the change of LMA size was required in 0.3% only. In the only case of regurgitation, it occurred during the application of fundal pressure. However, aspiration was avoided as defined by pH of inner mask of the PLMA not less than 4 and no radiological evidence as seen in simple chest X-ray after 24 h.  Yao et al. studied the use of LMA Supreme in 700 parturients with a mean body mass index (BMI) of 25 kg/m 2 and reported no case of regurgitation or aspiration. Effective airway in the first attempt was obtained in 98% cases in a mean time of 19 s.  However, all these studies are non-randomized single-center experiences and, therefore, the results should be interpreted with caution. Although, their prospective nature and large sample size provides good evidence and makes a case for use of such devices, especially PLMA or supralaryngeal airway devices with separate conduit for esophagus drainage in cesarean sections. It must be noted that the use of PLMA was preferred among the majority of staff anesthesiologists and senior house officers (SHOs) for failed intubation in surveys conducted in the UK. 
It is very difficult to plan randomized controlled trials (RCTs) among parturients due to ethical concerns. But with increasing evidence citing safe use of PLMA in cesarean sections, ethical concerns associated with conducting such kind of studies may fade over time. The number of subjects studied by Saini, et al.  are few (n = 60) and a RCT including many more subjects is required before any recommendations regarding this technique can be made.
If at all supralaryngeal devices are considered for routine use in cesarean sections, careful patient selection and adherence to strict protocols are necessary to ensure safety. Existing literature demonstrates that the elective use of PLMA is safe only in nonobese parturients (BMI < 30 Kg/m 2 ) who are made to fast for at least 6-8 h and do not have a difficult airway or a history of gastroesophageal reflux disease ,, . All patients should undergo a rapid sequence induction technique using thiopentone or propofol and suxamethonium or rocuronium (all studies mentioned earlier have used a muscle relaxant to get a good placement of LMA ,, ). In addition, it is advisable that cricoid pressure should be applied till proper LMA placement is confirmed. Han et al. further advocated continued application of cricoid pressure till the delivery of baby, as elevated abdominal pressure till delivery can pose a risk of aspiration.  These authors had used classic LMA in their study where the use of cricoid pressure seems logical till delivery. With the use PLMA or LMA Supreme, the relevance of continued cricoid pressure is debatable. Moreover, doubtful reliability of cricoid pressure in effectively preventing aspiration and its deleterious consequences should regurgitation occur with LMA in place makes this practice more questionable.
Anesthesiologists with adequate experience in using various LMAs should only venture using such a device for cesarean section in elective situations. Han et al. in their study, maintained inclusion criteria of at least 7 years of experience in using LMA for the performing anesthesiologists.  Adequate expertise in managing difficult airway is of utmost importance in such situations, as prompt decision has to be taken in favor of intubation in cases of leak, inability to maintain normoxia, or normocarbia with LMA. Inability to intubate or delay in intubation for want of adequate help from senior colleagues may turn fatal. Continued vigilance is additionally required throughout surgery, as regurgitation may occur anytime later. Strict criteria to diagnose regurgitation and aspiration should be included in the protocol during the initial phase of implementation.
In conclusion, there is still not enough evidence that the ETT can be replaced by a LMA or PLMA for use in general anesthesia for cesarean sections. However, if they are used at all, careful patient selection and an expert anesthesiologist are essential.
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