Prolonged use of the ProSeal laryngeal mask in ICU

EDITOR: The ProSeal laryngeal mask airway (PLMA) (Intavent Orthofix, Maidenhead, UK) provides a better laryngeal seal than the classic laryngeal mask airway (LMA) [1]. The PLMA incorporates a drainage tube in order to enhance the safety of the device, especially when used with positive pressure ventilation [2,3]. We report a case in which a PLMA was inserted as rescue airway in a failed tracheal intubation, and left in place for 40 h in the intensive care unit (ICU). A 52-yr-old male patient was admitted for endoscopic polypectomy of the left colon. His height was 175 cm, weight 80 kg and body mass index 26. He was otherwise healthy. The occurrence of severe post-polypectomy rectal bleeding required the patient to be transferred to the regular surgery ward. The patient underwent another endoscopy and the source of bleeding was found at level of the vascular axis of the large excised polyp, 38 cm from the anus. As the endoscopic attempt to control bleeding was unsuccessful an urgent open operation was necessary. On preoperative examination he was found to have a thick short neck with pronounced neck rigidity, micrognathia, macroglossia and Mallampati Class III. Anaesthesia was induced with fentanyl 100 μg and propofol 1.5 mg kg−1. The ability to maintain the airway was established but it was not possible to visualize the larynx during direct laryngoscopy and conventional tracheal intubation was impossible. After further preoxygenation, a size 4 PLMA was easily inserted at the first attempt using the recommended technique [1]. Anaesthesia was maintained with sevoflurane in oxygen-air mixture and cisatracurium for muscle relaxation. Volume-controlled intermittent positive pressure ventilation was instituted through a circle system with a tidal volume of 6 mL kg−1, an I:E ratio of 1:2 and a rate of 11 min−1. Peak airway pressure was 14–16 cmH2O, and a normal capnographic wave was obtained. A 14-G gastric tube was inserted via the PLMA drain tube. The patient required continuous fluid resuscitation, 8 units of packed red cells and 5 units of fresh plasma within a few hours due to the severe haemorrhagic shock. Haemostasis was successfully obtained during the open operation and at the end of surgery, which lasted 3 h 20 min, the patient was transferred to the ICU with the PLMA in situ. A fibreoptic bronchoscopic guided intubation through the channel of the PLMA with a 6.5 mm tracheal tube failed because the tube could not be passed into the trachea. In the ICU, the patient was sedated (propofol and remifentanil infusion), paralyzed (cisatracurium infusion) and mechanically ventilated (positive end expiratory pressure (PEEP) of 5 cmH2O) using the PLMA. The periodic evaluation of inspiratory-expiratory tidal ratio and auscultation at lateral sides of the neck assured us about the optimal cuff patency and absence of an air leak. A further 9 units of fresh plasma were transfused within a 12-h period in order to improve the patient's coagulation status. After the normalization of coagulation we decided to remove the PLMA in the operating room. After a bronchoscopic toilet the PLMA was removed with the patient completely awake and breathing spontaneously achieving a SPO2 of 96%. He returned to the ward a few days later. This is the first report of the use of the PLMA for 40 h without causing excessive pressure and likely mucosal damage to the hypopharynx. We delayed the decision to attempt a further fibreoptic bronchoscope guided intubation or a tracheostomy, because of the severe coagulopathy following the haemorrhagic shock. In our case report the successful time course of ventilation allowed a return to a safer coagulation status. As described in other clinical investigation the use of a laryngeal mask was exclusively confined as a bridge to subsequent percutaneous tracheostomy [4–6] or to facilitate a delayed extubation [7,8]. Recently, a case of lingual nerve injury has been reported associated with use of the PLMA [9] whilst other case reports of hypoglossal palsies were associated with use of the classic LMA [10,11]. Even though these complications are extremely rare, the frequency of cranial nerve injuries can be reduced by avoiding insertion trauma, using appropriate sizes and minimizing cuff volume [9]. It is advisable to limit airway pressures to less than 20 cmH2O during lung inflation and to use small tidal volumes (6–10 mL kg−1). Even though the PLMA is likely to be a safer device in preventing pulmonary aspiration than the classic LMA, because of its drain tube and improved airway seal, nevertheless the potential danger of its prolonged use is of concern [12,13]. When ventilation is controlled through the PLMA, the degree of gastric distension and, therefore, the risk of aspiration will theoretically increase with time. Our intention is not to encourage the routinary use of the PLMA in critically ill patients but only of reporting that the PLMA was an excellent airway ‘rescue’ device for prolonged use in our case. We wish to emphasize some recommendations to further improve the efficacy and safety of the PLMA in ICU. When the PLMA is used for prolonged periods, the respiratory function should be closely monitored and intracuff pressures should be checked periodically and maintained lower than 60 cmH2O. Meticulous attention to correct insertion technique, cuff inflation and fixation are all critical when using such device for positive pressure ventilation. Close evaluation of the inspiratory-expiratory volumes ratio ensuring that the peak inspiratory pressures are below 20 cmH2O when using volume control mode of mechanical ventilation. Finally, the risk of gastric inflation should be actively excluded by listening over the neck and abdomen with a stethoscope [14]. C. Di Iorio T. Cafiero P. Varriale R. Spatola R. Mannelli R. M. Di Minno 1Department of Anaesthesia, Postoperative Intensive Care, Burn Center and Hyperbaric Center, A. Cardarelli Hospital, Napoli, Italy