Mirkov M: Letter to the Editor; Use of LMA's. The Internet Journal of Anesthesiology 1998; Vol2N2: http://www.ispub.com/journals/IJA/Vol2N2/letter.htm ; Published April 1, 1998; Last Updated April 1, 1998.

Dear Sir:

I am anesthesiologist working in Kuwait and since 7 to 8 months reading the journal where you are Editor-in-chief. It's interesting and informative. Last time I found the quite amazing story of Mr. Hyner regarding his experience as a patient receiving ether anesthesia. This encouraged me also to write something which, I believe, is interesting, although not at all related to Mr. Hyner's story.

As everybody nowadays I am a regular user of LMA (laryngeal mask airway) in OT. Although maybe not in all patient's positions as Dr. Brain, the inventor of LMA, shows in his publications and videos, I regularly use it for patients in lateral decubitus positions. Commonly these are cases of short or medium duration procedures where alternative techniques like local infiltration or regional anesthesia are refused by the patient. Here we talk of surgeries for dorsal PNS (pilo-nidal sinus) not rarely infected, lipoma, atheroma, carbuncle, sebaceous cyst situated on the back, dorsal surface of the neck or head of the patient. Sometimes these are cases for short surgical cleaning or dressing of lesions on the lower extremities where again lateral position of the patient is required by the surgeon. In all these or similar cases if regional or local anesthesia is refused by the patient or not possible due to infected skin close to the place of eventual anesthesia, general anesthesia is the alternative. Generally two techniques are possible:

1. Mask anesthesia on a spontaneously breathing patient or
2. General anesthesia on an intubated patient with control of it's breathing.

The known inconvenience of a mask technique is the difficulty to maintain patent airway in this position especially in obese patients hence eventual hypoxia and hypercapnia, which could be rather dangerous. Remember that many of these patient suffer additional medical problems like a combination of DM, HTN, IHD with or without renal impairment. Another drawback is the hypoventilation accompanying the deep levels of inhalational anesthesia or TIVA. Mask anesthesia does not protect the patient against eventual vomiting, regurgitation and possible aspiration during the procedure. A technique with endotracheal intubation solves these problems but carries the well known possible inconveniences like postoperative sore throat and irritation of the larynx, risk of one lung hypoventilation due to displacement of the ET, increasing of BP, HR, ICP due to the laryngoscopy and intubation itself. The technique is more complicated and risky especially if the laryngoscopy reveals a patient difficult for ETI (endotracheal intubation).

In the last 10 years LMA's increasingly became a good alternative to ET (endotracheal tubes). They do not protect against possible aspiration and could be ineffective in allowing IPPV in some cases due to leak or high resistance in the airways. However, they have the advantage to be very easy for use, less traumatic and secure the airway in most cases where ETI is impossible. LMA's have been recently included in the algorithm for difficult ETI of the ASA.

The usual way of insertion of LMA is in supine well anesthetized patient. After proper fixation and testing of the ventilation the positioning required for the surgery is accomplished. In my personal experience with every day use of LMA since 1992 there are some critical points for successful use of LMA.

• First: the position of patient's head. I always prefer slight neck extension by shifting the patient's pillow a bit down below the shoulders.
• Second: patients head has to be strictly in the midline and the black line of the LMA's tube has also to be strictly in the midline.
• Third: observation of the movement of the larynx during LMA insertion.
• Forth: Nobody else but the anesthetist himself or herself has to inflate the LMA after introducing it. I don't believe that overinflation helps to overcome a possible leak.
• Fifth: fixation of the LMA sometimes easily displaces it. Changing of the patient's position is also critical regarding eventual displacement of the mask. This could be quite a difficult problem in an already paralyzed obese or heavy patient. Having in mind all this and being sometimes unsatisfied using the LMA, I started inserting LMA's in patients already in lateral decubitus position.

Although this could sound to somebody risky or unwise, the technique appears to me to be easy, reliable and with advantages and I've been using it since more than one year. I use this for patients from all ASA groups going to have elective procedures, in lateral decubitus position, surely fasting for the last night. Patients with possible high airway resistance such as COPD receive alternative techniques of anesthesia. The patients have their usual medications and premedication in the ward and if it is not included in the premedication they receive methoclopramide iv prior to induction except if it's contraindicated (Parkinson's disease). After fixation of an iv line and the monitors (ECG, SpO2, NIBP) patients are asked to take lateral position. Then the induction starts usually including xylocaine, alfentanyl, propofol, 100% O2 and an inhalational agent via Magill's circuit. The goal is slow, smooth induction with preserved spontaneous breathing. Even if the breathing is depressed this doesn't create any problem since the LMA insertion is immediate and very easy. We just extend the head of the patient with one hand while inserting the mask with the other. Sometimes a help from assistant in extending or supporting the head is important. Fixation of the LMA as usual and afterwards muscle relaxant if indicated for IPPV. LMA we tend to and are usually removed in the Recovery Room, from an awake, cooperative patient who is still in lateral decubitus position.

Moreover, most of these patients prefer to be on their side to avoid possible pain from pressing the wound when lying supine. Advantages of LMA insertion in patient already in lateral decubitus position for me are:

• you don't need anybody to help in positioning the patient especially if patients are shy or due to religious reasons don't like to be touched by persons from the opposite sex;
• you don't need to position an already anesthetized patient with depressed vital functions due to the induction;
• you avoid possible displacement of an already fixed LMA in paralyzed, eventually obese or heavy patient during it's turning to lateral position;
• you have much more secure airway compare to simple mask technique and facilities to properly assist or control patients ventilation if it becomes necessary in the middle of the procedure;
• less possible regurgitation in left lateral decubitus due to increase angle of the GE junction.

Possible disadvantage could be the difficulties to control a leak around LMA. We haven't faced such a situation until now and possible solution could be fast repositioning in supine position and securing patient's airway. As already mentioned I've used this technique since more than a year without problems and recently even helped to colleagues interested to do it for similar cases. I've not red something similar in the literature and kindly ask for your opinion and comment.

Sincerely yours

Miroslav Mirkov M.D.
Specialist in Anesth.&ICU
Al Amiri Hospital
Kuwait

E-mail address: leglo@hotmail.com

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