Evaluation of a new technique for Macintosh oral intubation

ABSTRACT

Laryngoscopic view grades, according to modified Cromack and Lehane [C and L], I and possibly IIA denote easy while IIB, III and IV difficult intubation. Over the last three years, using Macintosh blade [MCB] for oral intubation in adults, the author found that by manipulating the proximal end of the tube with your fingers, the distal end moves facilitating intubation. The aim of this study is to evaluate a new technique invented by the author, which is called the manual tube control [MTC] technique, during MCB oral intubation in adults. The technique depends mainly on control of the proximal end of the endotracheal tube [ETT] between the thumb, the index and the middle fingers of the intubator's right hand and manipulating according to the laryngoscopic view. Material and In a prospective single blind randomized clinical study, oral tracheal intubation using MCB size 4 was evaluated in 100 adult patients scheduled for elective surgery under general anesthesia, according to the tube holding technique. Inclusion criteria are American Society of Anesthesiologists [ASA] I adult patients who showed Mallampati III and IV during preoperative airway assessment and then initial laryngoscopic view [C and L] III and IV [without external laryngeal pressure] after general anesthesia. The study excluded cases that showed limited mouth opening [less than 2 fingers], problems related to mouth, teeth, pharynx, cervical spine, gastric reflux, sleep apnea and cases of pregnancy or bad anesthetic history. 7 cm height foam pillows were put under the patient's head, neck and shoulders and the initial laryngoscopic view was improved with external laryngeal pressure. The patients were divided into two groups according to the method of ETT holding during intubation group U 50 patients where the ETT was held in the usual way, and group M 50 patients where the MTC technique was used. Patients who could not be intubated after two trials in the same group would be shifted to the other group. If the patients still could not be intubated after two trials in the other group, LMA FastrachT [intubating laryngeal mask airway] would be used. Both groups were comparable as regards demographic data, operative procedures and airway variables P>0.05. In group U, it was easy to intubate all cases of view I [C and L] in the first trial and only 4 cases [57%] of group IIA in the second trial while all other cases were shifted to group M where they were successfully intubated. All group M cases were successfully intubated in the same group. The total number of successful intubations using the group M technique was more than that using the group U technique with a highly significant difference P<0.001. LMA FastrachT was not needed in any case and no complications were recorded. The MTC technique is an efficient way for adult oral tracheal intubation using MCB size 4 even in cases of difficult laryngoscopic views