THE laryngeal tube-S™ (LTS™; VBM Medizintechnik, Sulz, Germany) is a new supraglottic airway-management device introduced into the European market in 2002 (fig. 1). It is a newer generation of laryngeal tube which is fitted with a second lumen serving for suctioning, and free gastric drainage. This case report describes the use of the LTS™ for emergency airway management of a parturient after failed attempted tracheal intubation.
A 27-yr-old parturient was brought to the operating theatre for urgent Cesarean section due to prolonged rupture of the amniotic membrane. Her medical history was unremarkable. She had eaten nothing for about 12 h and didn’t have any symptoms of gastro-esophageal reflux. Upper-airway examination revealed score II of Mallampati,1an interincisor gap of about 4 cm, and a thyromental distance of about 2.5 finger breadths. She had limited (less than 30°) extension of the neck. General anesthesia was chosen due to the patient’s refusal of regional anesthesia. After preoxygenation, the patient was anesthetized with a rapid sequence induction: using 450 mg of sodium thiopental and 120 mg of succinylcholine. The Sellick maneuver was applied as recommended by an assistant. A grade III view of the larynx was obtained using a size-3 blade McIntosh laryngoscope. Two attempts at intubation, at the optimal sniffing position by the clinical-anesthesia 3-year resident, without and with a stylet, failed. Release of cricoid pressure didn’t improve the view, and the pressure was applied again. A senior anesthetist was called. The oxygen saturation decreased to less than 50%. Two-person manual bag and mask ventilation with 100% oxygen was difficult and resulted in only a modest increase in oxygen saturation (60–70%). A size-4 LTS™ was blindly inserted about 5 min after induction, and its cuff inflated with about 80 ml of air. The patient could be ventilated easily and the oxygen saturation increased to 97% using manual ventilation with 100% oxygen. The patient regained consciousness and as she started breathing she began to move her eyelids. Regurgitation of yellowish stomach contents began with the LTS™ in place but it was drained by the suctioning lumen of the LTS™ and no change in oxygen saturation was detected. A nasogastric tube was inserted and about 30 ml of fluid drained from the stomach. At this time the patient was alert and cooperative. She was reassured and the LTS™ was removed in the presence of the consultant anesthetist. Examination of its cuff showed no blood traces. The obstetrician was asked if it was possible to administer regional anesthesia and she agreed after she assessed the fetal heart sound with a sonicaid. Afterwards, there was no evidence of aspiration at any stage of the procedure. Spinal anesthesia was administered and a healthy girl was delivered (weight, 3900 g; APGAR scores 9 and 10 after 1 and 5 min, respectively). A full explanation of the events was given to the patient and her husband. The patient and her baby were discharged from the hospital in good condition 2 and 4 days later, respectively.
Difficult or failed tracheal intubation is an important cause of anesthetic-related maternal morbidity and mortality.2Regurgitation is a rare but significant cause of morbidity and mortality after failed tracheal intubation.3
Considering our management the following should be noted.
Omission of antacid premedication was an error.
The selected dose of succinylcholine was relatively high.4
Release of the Sellick maneuver after failed intubation and difficult ventilation are controversial and not routinely recommended.5
It was quite possible that the patient could have been intubated successfully, if another size or type of laryngoscope blade had been used. However, these issues are not the focus of this case report.
Although the Laryngeal Mask Airway ™ (LMA ™; Laryngeal Mask Company Limited, San Diego, CA) has been successfully used and promoted for management of failed obstetric intubations6–8it is not effective in all patients.9The LMA ™ may yield in unsuccessful ventilation and gastric inflation due to low median airway-seal pressure and it does not reliably protect against aspiration of regurgitated stomach contents.10A recent case report regarding the use of the ProSeal ™ laryngeal mask airway (PLMA ™; Laryngeal Mask Company Limited) for emergency airway management after failed tracheal intubation during Cesarean section has been published.11Also there are a few reports describing prevention of aspiration of gastric contents with the PLMA ™in situ .12–15These reports suggest the effectiveness of the PLMA ™ to maintain the airway and prevent aspiration in elective and emergency situations. However, in our case a PLMA ™ was not ready to use.
The LTS™ may be a good choice for emergency airway management.16–18It may provide a higher airway seal than the LMA ™: an airway pressure as high as 40 cm of H2O would be achievable without gastric inflation and its insertion time is also comparable with that of the LMA ™.19,20Appropriate positioning of the LTS™ has been verified with fiberoptic endoscopy in all patients.20
In contrast to the combitube, the LTS™ has only one adapter that may be connected with a ventilation device, whereas the remaining connector can only be connected to a suction adapter. This may provide additional patient safety in order to prevent an inexperienced user inadvertently attaching the Y-piece to the esophageal tubing.
The LTS™ has encountered some minor problems, so that some may consider it a suboptimal device. Firstly, there are few controlled trials comparing the LTS™ with other similar supraglottic devices such as the PLMA ™, LMA ™, and combitube. Secondly, it has never been tested in hypoxic and/or hypercarbic patients, as in our presented case. Thirdly, there may be concerns, although unlikely, that the LTS™ may induce dangerous effects like the esophageal obtorator. Fourthly, there may be dangerously high cuff pressures when the device is used in an emergency situation to secure the patient’s airway. This is not a major problem, since the cuff pressure of the LTS™ (80 cm of H2O) has been reported to be much lower than that of the combitube (80–300 cm of H2O) and the LMA ™ (100–250 cm of H2O).20,21
In conclusion, in the future, the LTS™ may have a role in emergency obstetric airway management.
Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran. email@example.com