This case clearly demonstrated the SJOV via WNJ could effectively maintain adequate oxygenation/ventilation during long time fiberoptic intubation in an apnea patient with morbid obesity and OSA after partial failure of two hand pressured mask ventilation, without obvious complications. This may provide a new effective approach for difficult airway management in these patients.
According to the world health organization (WHO) standards established 1989, body mass index (BMI) ≧28 is defined as obesity, BMI≧40 is defined as morbid obesity . Adipose tissue accumulated in pharyngeal can make patient’s pharyngeal cavity narrow and make the oropharyngeal muscles and soft tissue collapse, obstructing the airway [12, 13]. Obviously, this increases the patient’s workload of breathing and reducing functional residual capacity, causing ventilation/perfusion mismatch,eventually hypoxia and intolerance of hypoxia . The incidence of difficult intubation in morbid obesity patients during general anesthesia induction undergoing abdominal surgery can be as high as 24% , and the awake intubation may be required in about 8% of patients . The potential upper respiratory tract obstruction in OSA patient contribute to its high perioperative complication rate at about 19.6% . The incidence of failed intubation in OSA patients is10 times higher than normal , while the incidence of intubation failure about patients with morbid obesity and OSA increases to 100 times [17, 18]. We discussed awake intubation with this patient on pre-anesthesia visit, but the patient was nervous and could not be comforted and refused the plan. In addition, the patient’s large neck circumference makes it difficult to identify the cricothyroid membrane. Since we underestimated the difficulty of this patient’s airway, and this patient was very nervous and unwilling to be stimulated, we did not choose awake intubation or awake look. Even though this case was an unanticipated difficult airway, we were able to maintain and improve oxygenation using WEI nasal jet tube for supraglottic jet oxygenation and ventilation,because we have some experiences applying this device on obese patients. We have completed a randomized controlled study(Registration number, ChiCTR 1,800,017,028) of supraglottic jet ventilation to improve oxygenation in obesity patients, and the results revealed that Nasal Jet tube could prevent patients suffering from desaturation during propofol-remifentanil protocol undergoing hysteroscopy. We are in the process of writing a paper.
The most important features of supraglottic airway is most characteristic of the patient with pathological obesity and OSA is serious airway collapse after anesthesia due to hypertrophy of the patient’s tongue,epiglottis and supraglottic muscles . Airway collapse make supraglottic airway narrower, making the air flow of the mask pressurized ventilation difficult to pass the narrow area . WNJ can pass the narrow airway and support the collapse and resolve the ventilation problem. WNJ is designed to be soft to void injury of nasal mucosa damage and bleeding. The evaluation of nasal cavity and the use of the lubricant also ease its insertion and minimizing nose bleeding. In our case, nasal jet tube maintained this patient’s oxygenation. According to the “Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults” , muscle relaxant can make tracheal intubation easier, and prevent laryngospasm, so we administered rocuronium. Succinylcholine should be a better choice in this case, but we don’t have it in our department. With quick and short-acting effect, rocuronium could exert muscle relaxant effect 60 s after administration, which is equivalent with succinylcholine.
The capacity of tolerance to hypoxia in pathological obese patients with OSA is reduced significantly. It is critical in this case to have an effective method to maintain the patient’s oxygenation during intubation because of the shorter Oxygen Saturation Falling Time (OSFT) . The definition of OSFT is the time of the patient’s SpO2 dropped to 90% after full oxygenation 100% oxygen inhaled and removed nitrogen [22, 23]. The obese patient’s OSFT is only 163 s due to the increased oxygen consumption and the changes in the airway described above,but the average of a normal adult is 526 s [22,23,24]. So it is almost impossible to complete this fiberoptic intubation without maintaining effective oxygenation using SJOV via WNJ for 7 min in this anesthetized and paralyzed morbid obese patient with OSA. This patient didn’t reach “can’t intubate and can’t ventilate”(CICV) so that LMA placement was not tried, nor did the emergent tracheotomy was considered.
In combination with previous publications [1, 7,8,9,10,11], It seems that SJOV has following advantages compared to the transtracheal jet ventilation (TTJV) recommended by American Society of Anesthesiologists (ASA) guidelines for the management of difficult airway. First,SJOV via WNJ is less invasive than TTJV which may increase the incidence of barotrauma barotrauma [7, 19]. Secondly, it usually take longer time to perform effective TTJV than placement of WNJ in the nose and could be very difficult to achieve successful TTJV in obese patient with thick neck. Thirdly, it is convenient to monitor ventilation using the built-in port for PetCO2 monitoring in WNJ. Forth and most importantly, SJOV maintain the open feature of airway during jet ventilation, minimizing or preventing the severe barotrauma, often seen during the use of TTJV, especially in emergent difficult airway management .
In summary, SJOV via WNJ seems to be an effective new approach to maintain adequate oxygenation/ventilation during difficult airway management in an apnea patient with morbid obesity and OSA.