Hiccup is frequently triggered by the induction agent, face mask ventilation or airway device insertion and is notoriously difficult to treat with systemically applied drugs. It is associated with lower oesophageal reflux with one author noting a frequency as high as 40% . The risk of hiccup-related aspiration is unknown, although in principle it could be reduced by use of an airway device that isolates the respiratory tract from the gastrointestinal tract. Perhaps patients who develop hiccup should be paralyzed and intubated, but non-depolarizing muscle relaxants take 2-3 min to take effect, potentially leaving the patient at risk during this period. The ProSeal™ laryngeal mask airway (PLMA) is a relatively new laryngeal mask device that isolates the respiratory from the gastrointestinal tract, has a drain tube for venting-regurgitated fluid and does not require muscle relaxants for insertion . We describe three cases where the PLMA may have prevented hiccup-related aspiration of gastric contents.
A 53-yr-old, 61 kg female presented for a knee arthroscopy. She had no history of gastro-oesophageal reflux, took no medication and had been fasted for 8 h. The airway management plan was to use a size 4 classic laryngeal mask airway (LMA). Following induction of anaesthesia with propofol 180 mg and commencement of face mask ventilation, she developed hiccups. A size 4 PLMA was easily inserted using the digital technique and while the cuff was being inflated approximately 30 mL of bile-stained fluid was vented from the drain tube. Slight pressure was applied along the airway tube to increase the efficacy of the seal with the upper oesophagus. A gastric tube was inserted via the drain tube and 20 mL of bile-stained fluid was suctioned from the stomach. The PLMA was fixed to the face with tape. Fibreoptic inspection of the pharyngolarynx and proximal trachea revealed no evidence of pharyngeal regurgitation or aspiration, respectively. The hiccups were refractory to treatment with atropine, but ceased spontaneously after 10 min. The case was completed uneventfully with the PLMA.
A 58-yr-old, 128 kg male presented for a laparoscopic cholecystectomy. He had a history of twice weekly gastro-oesophageal reflux, which was controlled by omeprazole 40 mg, and he had been fasted for 6 h. The airway management plan was to perform laryngoscope-guided tracheal intubation. Following induction of anaesthesia with alfentanil 1.5 mg and propofol 300 mg and commencement of face mask ventilation, he developed hiccups. A size 5 PLMA was easily inserted using the digital technique, the cuff inflated with 20 mL air, ventilation established and the PLMA fixed to the face. Rocuronium 50 mg was administered. However, before the onset of muscle relaxation approximately 20 mL of clear fluid was vented from the drain tube. A gastric tube was inserted and 10 mL of clear fluid was suctioned from the stomach. Fibreoptic inspection of the pharyngolarynx and proximal trachea revealed no evidence of pharyngeal regurgitation or aspiration, respectively. The oropharyngeal leak pressure was greater than 50 cmH2O and the case was completed uneventfully with the PLMA.
A 49-yr-old, 94 kg male presented for a laminectomy. He had no history of gastro-oesophageal reflux, took no medication and had been fasted for 6 h. The air-way management plan was to use a size 5 PLMA. Following induction of anaesthesia with alfentanil 1 mg and propofol 250 mg the PLMA was easily inserted with the patient in the supine position using a laryngoscope-guided, gum elastic bougie-guided technique; however, hiccupping was triggered by cuff inflation. Slight pressure was applied along the airway tube as the PLMA was fixed into position. Just as a gastric tube was about to be inserted, 15 mL of bile-stained fluid was vented from the drain tube. Gastric tube placement was rapidly completed and 100 mL of bile-stained fluid was removed from the stomach. Hiccups were refractory to atropine, but responded to metoclopramide 10 mg. Fibreoptic inspection of the pharyngolarynx and proximal trachea revealed no evidence of pharyngeal regurgitation or aspiration, respectively. The case was completed uneventfully with the PLMA.
These cases illustrate that the PLMA can prevent aspiration of regurgitated gastric contents associated with hiccup. One of the main advantages of the PLMA over the classic LMA is that it provides better protection against regurgitation, as it has a drain tube, forms a better seal with the upper oesophageal sphincter and malposition is more easily detected . There is evidence from clinical studies that the correctly positioned PLMA isolates the gastrointestinal tract from the respiratory tract, and evidence from a cadaver study that the efficacy of seal with the oesophagus is 50-80 cmH2O .
In Cases 1 and 2, the PLMA was inserted after the onset of hiccup to provide airway protection. The PLMA offers advantages over laryngoscope-guided tracheal intubation in this situation, as insertion can take place without waiting for muscle relaxation. A possible disadvantage is that the PLMA might increase the severity of hiccup-related reflux. However, once the distal cuff is correctly positioned it should protect the airway, as in the current cases. If necessary, the patient can be intubated once hiccup has subsided and the stomach emptied with a gastric tube. We elected not to intubate any of our patients, as the PLMA was functioning adequately. Also, there is always some risk when exchanging one airway device for another. In principle, other extraglottic airway devices with drain tubes, such as the laryngeal tube suction and the Elisha airway, might also be useful in this situation.
In Case 3, the PLMA was inserted before the onset of hiccup, which was triggered by cuff inflation. The overall incidence of hiccup with the classic LMA is about 1.4% and it is more common in the placement phase than the maintenance or emergence phases. Stretching pharyngeal mechanoreceptors in cats and upper oesophageal receptors in human beings causes hiccup and is the probable mechanism of hiccup with extraglottic devices. Hiccup may be associated with transient relaxation of the lower oesophageal sphincter after LMA insertion. Skinner and colleagues , in a 1998 study of 40 adults undergoing gynaecological laparoscopy with the LMA, noted that lower oesophageal reflux occurred in the only patient in whom hiccup occurred. Roberts and Goodman  reported a similar finding for intubated patients.
Borromeo and colleagues  reported a similar case of regurgitation without aspiration in a 40-yr-old female in whom hiccup commenced after PLMA insertion. The authors hypothesized that during hiccup fluid accumulated in the lower oesophagus until sufficient pressure built up to allow sudden escape through the drain.
In the first and third cases, we applied force along the shaft of the PLMA to increase the efficacy of seal and to ensure that there would be no displacement of the distal cuff from the hypopharynx prior to fixation. Stix and colleagues , in 2002, noted that securing the PLMA with moderate longitudinal force along the airway tube improved the seal with the hypopharynx, but provided no supporting data.
Pharmacological treatment for hiccup is based on empirical findings rather than being ‘evidence-based’. Kanaya and colleagues  reported the successful use of atropine to treat hiccups in three patients after LMA insertion. In contrast, we found that hiccup was resistant to atropine. We also found that hiccup responded to metoclopramide in one case, although this may have been co-incidental.
We conclude that the PLMA can protect the airway from regurgitation associated with hiccups. The PLMA may be a useful alternative to laryngoscope-guided tracheal intubation in preventing hiccup-related aspiration triggered by the induction agent or face mask ventilation.
1Department of Anaesthesia and Intensive Care, James Cook University, Cairns Base Hospital, Australia.
2Department of Anaesthesia and Intensive Care Medicine, Leopold-Franzens University, Innsbruck, Austria.
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