To our knowledge, this is the first report that elucidates the difference of LMA and ETT in retinoblastoma nucleation surgery. This retrospective study shows that LMA intubation provides more stable perioperative conditions and reduces the use of inhaled anesthetics during the procedure. Based on the above findings, LMA intubation is recommended for children undergoing eye enucleation surgery.
Retinoblastoma is a rare eye cancer found in children. Although systemic chemotherapy and radiation therapy can be used in the treatment of retinoblastoma; in some circumstances, the doctors have to conduct enucleation as prophylactic means for distant metastases and recurrence [7]. The functional anatomy of the airway in children is important for enucleation because the airway changes in size, shape and position throughout its development from the neonate to the adult. In the larynx, the cricoid cartilage occupies the narrowest part. A rapid phase of growth occurs in the first three years of life, and the unique anatomical features in children contribute to loss of upper airway space and poor visibility during intubation [8]. Although fiberoptic evaluation and high-resolution computed tomography can provide important messages, pediatric airway management remains a great challenge [9–10]. The laryngeal mask airway and endotracheal tube are the classic tools to management the airway of children receiving general anesthesia. In a systematic review and meta-analysis covering 1,433 patients undergoing laparoscopic surgery, LMA was found to permit more stable perioperative haemodynamic parameters and less stress than endotracheal intubation [11]. For ophthalmic surgery in pediatric patients, the use of an LMA is also beneficial for less fluctuation in intraocular pressure [12]. However, endotracheal intubation is criticized because it induces more undesirable stress responses and hemodynamic alterations due to an elevation in serum cortisol [13]. Similarly, in our research, the heart rate before skin incision was significantly lower in the patients with LMA placement in Group B than in those receiving endotracheal intubation in Group A, suggesting less adverse effect on the circulation. LMA, as a supraglottic ventilation device, has no glottic exposure during intubation and no harm to airway with little cardiovascular stress. Thus, children might have better accessibilities for general anesthesia with LMA.
As we know, the strong influence induced by tracheal intubation might interfere with circulation and respiratory systems due to the release of stress hormones, such as endothelin and thromboxane A2, in response to the stimulus [15]. Compared to LMA, endotracheal intubation is less endurable at the same anesthesia depth so that sevoflurane is commonly used to minimize the stimulus of the endotracheal intubation. In our research, 45.71% of the patients received the inhaled anesthetic drug (sevoflurane) when using endotracheal intubation while in the LMA group, only 8.70% of the patient received sevoflurane. The application of sevoflurane could increase the risk of memory impairment. Especially for children who had undertaken repeated and long-term general anesthesia, the harmful effects were more susceptible and accumulated [17]. LMA intubation decreases the application of inhaled drugs in children undergoing eye enucleation surgery and thus decreases the risk of memory impairment.
Perioperative complications may occur during the process of endotracheal intubation or LMA place, such as laryngeal spasm after extubation, ocularcardiac reflex, desaturation, arrythmia, and oral injuries (teeth, lower lip, tongue, soft tissue, vocal cord, etc). Laryngospasm is most commonly seen in the post-extubation phase of anaesthesia [18]. In the majority of cases, laryngospasm is self-limiting. However, sometimes laryngospasm persists and if not appropriately treated, it may result in serious complications that may be life-threatening. In our study, one child experienced laryngospasm (1/58, 1.72%) during general anesthesia as manifested by stridor and back to normal spontaneously. We also witnessed in one case a second attempt of LMA insertion due to poor alignment of laryngeal mask, and LMA was successfully reentered after retreating and adjust the LMA. Ocular cardiac reflex is another common perioperative complication during enucleation [22]. In our research, the occurrence of ocular cardiac reflex was relatively higher in those receiving LMA than those receiving endotracheal intubation while the proportion of patients using retrobulbar block was comparable.