[Evaluation of a protocol for predicting difficult airway in routine practice: interobserver agreement]. / Evaluación de un protocolo de predicción de vía aérea difícil en la práctica habitual: estudio de concordancia.

OBJECTIVES: To evaluate a protocol for routine assessment of potential risk factors for difficult airway intubation in an anesthesia department, by measuring interobserver agreement and the behavior of the factors in a predictive model. MATERIAL AND METHODS: A cross-sectional study group of 320 consecutive patients undergoing major surgery requiring orotracheal intubation was assessed for possible difficult airway. We calculated interrater agreement for recording of the Mallampati score, thyromental distance less than 6 cm, thick neck, kyphosis, small mouth, macroglossia, and dental prosthesis during the preanesthesia examination (by an anesthetist) and on the day of the operation (by an anesthetist and a resident). We constructed a model to predict difficult intubation (requiring 3 or more attempts). RESULTS: The kappa indices of agreement between the anesthetists at the preoperative examination and in the operating room or the resident were all less than 0.6. Factors like thyromental distance, small mouth, and kyphosis had kappa indices less than 0.21. The kappa index between the resident and the anesthetist in the operating room was over 0.55. The only factor that had a different level of agreement was the presence or not of a dental prosthesis. None of the studied individual factors, nor these factors in association with the Mallampati score, achieved significance in a bivariate regression model to predict difficult intubation. CONCLUSIONS: There is poor interobserver agreement on factors for predicting difficult airway in comparisons between preoperative and operating room assessment by an anesthetist or a resident. The individual predictive factors and their association with the Mallampati score did not prove useful for predicting difficult intubation.

[Supreme laryngeal mask airway vs the I-gel supraglottic airway in patients under general anesthesia and mechanical ventilation with no neuromuscular block: a randomized clinical trial]. / Estudio comparativo entre las mascarillas laríngeas Supreme e I-gel en pacientes con anestesia general sin bloqueo neuromuscular, con ventilación mecánica.

OBJECTIVE: The Supreme Laryngeal Mask Airway (SLMA) and the I-gel Supraglottic Airway (IGSA) are recently introduced devices incorporating a gastric channel. This study assessed the ease of insertion of the devices and their efficacy in mechanical ventilation. MATERIAL AND METHODS: Eighty-five patients undergoing major outpatient surgery under general anesthesia were randomized to 2 groups for intubation using the SLMA or the IGSA. After induction of general anesthesia, the assigned mask was inserted and positioning was checked with a fiberoptic scope. Ease of insertion was evaluated. Seal pressure was measured and the following ventilatory parameters were recorded 10, 30, and 60 minutes after the start of surgery: peak pressure, mean pressure, compliance, and the ratio of tidal volume to respiratory frequency. Conditions at the moment of inserting the nasogastric tube were also noted. RESULTS: First-attempt placement of the airway was possible in 95.2% of patients using the SLMA and in 86% using the IGSA (P = .147). The mean times required for placement were 27.1 seconds for the SLMA and 32.5 seconds for the IGSA (P = .195). The nasogastric tube was inserted on the first attempt in 97.6% of patients with an SLMA and in 85.7% of patients with an IGSA. The mean times required for tube insertion were 9.5 seconds through the SLMA and 22.1 seconds through the IGSA (P < .001). Seal pressure and compliance were similar in the 2 groups at the start of surgery and at 10, 30, and 60 minutes. The incidences of complications during surgery and at 90 minutes were likewise similar (P = .945 and P = .698, respectively). CONCLUSIONS: The SLMA and the IGSA are easy to put into position on the first attempt. It is easier to insert the nasogastric tube through the gastric channel of the SLMA. Both devices provide an effective seal and the incidences of complications were similar for both in the patients we studied.

[Air seepage from endotracheal tube cuffs during anesthetic procedures. How to solve this problem without changing tubes? An experimental model using human tracheas]. / Pérdida de aire en los manguitos de los tubos endotraqueales durante el procedimiento anestésico. Cómo solucionar este problema sin cambiar el tubo? Modelo experimental con tráqueas humanas.

OBJECTIVES: To demonstrate by an experimental model that a continuous medicinal airflow system giving a pressure of 30 cmH2O effectively stops leakage from endotracheal tubes. MATERIAL AND METHODS: Ten tracheas with their main bronchi were removed from cadavers with no pulmonary disease. The tracheas were placed vertically and tubes previously perforated with increasing caliber needles were inserted and connected to a continuous flow system. The flow of medicinal air generated in the cuff was monitored with a flow meter and pressure was measured with a manometer. When a pressure of 30 cmH2O was reached, the trachea was filled with saline. We then observed the moment at which, when pressure fell, the saline began to leak from the bronchi. The levels observed were expressed as arithmetic means and standard deviations. RESULTS: No leakage was observed when the flow produced pressures above 10 cmH2O for 25 G caliber holes, above 15 cmH2O for 24 G holes, or above 20 cmH2O for 25 G, 21 G, 20 G, 18 G or 16 G holes. For 14 G holes, a flow producing pressures over 25 cmH2O were needed. Pressure up to 80 cmH2O was required to stop leakage from a scalpel cut. CONCLUSIONS: We found that adjusting flow and pressure is a valid way to stop leakage from small holes. The method does not control leakage from large holes or cuts.