Evaluation of Glottic Visualization and Ease of Intubation at Induction of General Anesthesia

Aim: To compare the frequency of better glottic visualization and ease of tracheal intubation in Macintosh versus McCoy blades. Study design: An observational analytical study. Settings: Department of Anesthesia, Lahore Medical and Dental College/Ghurki trust teaching hospital, Lahore. Study duration: Six months (2nd September 2017 to 1st March 2018) Methods: After approval from research, education and clinical audit department, we selected 60 patients for elective procedures under general anesthesia of age ranges from 20-40 years including both males and females. Patients were randomized by lottery method into two groups I & II. Laryngoscopy was performed with McCoy in group I and with Macintosh in group II and the best possible view of the glottis was obtained. After achieving best possible glottis view of each patient, vocal cord visualization was determined according to Grade-I to IV. Ease of tracheal intubation was also noted. Results: The demographic data was comparable in both groups. In this study, we have found better glottic visualization in 60.0% of patients with Macintosh blade (group II) and with McCoy blade (group I), it was 83.33% (p-value = 0.045). Ease of intubation was 73.33% with Macintosh blade (group II) and with McCoy blade (group I), it was 93.33% (p-value = 0.038). Conclusion: We concluded that frequency of better glottic visualization and ease of tracheal intubation with McCoy blade is higher as compared to Macintosh blade. Keywords: Endotracheal intubation, Glottic visualization, McCoy blades, Macintosh blades.

Effectiveness Comparison of Using Macintosh Blade and Mccoy Blade For Endotracheal Intubation In Anesthesia Residents

Introduction: Laryngoscopy is one of the critical points in the intubation process and a mechanical trauma that provides noxious stimulation, affecting cardiovascular, respiratory, and intracranial changes. Practitioner competence is a significant factor that supports laryngoscope intubation procedures. That can influence the intubation duration and amount of mechanical trauma besides caused by laryngoscope type. Objective: To analyze the effectiveness of using Macintosh blade compared to McCoy blade in intubation laryngoscopy by Anesthesia Residents. Materials and Methods: This research is an experimental study in adult patients who underwent elective surgery at GBPT Dr. Soetomo Hospital. Intubation did by Anesthesia Residents at levels 5-9 using Macintosh or McCoy Laryngoscope and chosen randomly. The data of laryngeal visualization (Cormack Lehane), hemodynamics (blood pressure, pulse), pain scale (qNOX), intubation time length, and pain scale data (VAS) after extubation were taken during intubation laryngoscope. Result and Discussion: The study was conducted on 28 samples that met the criteria. Anesthesia Resident's competence levels based on the semester in both groups laryngoscopes were not different (p 0.868). Based on laryngeal visualization data laryngoscopy, the McCoy's blade had better visualization with CL 1 at 85.7% of the samples and p-value 0.020. This good visualization makes it possible to speed up the laryngoscope-intubation in the McCoy blade group with a significant difference of time compared to the Macintosh blade group. Hemodynamic parameters, there were significant differences for hemodynamics increase. In the Macintosh blade group, the blood pressure and pulse were significantly increased after laryngoscopy intubation. The pain scale during the intubation procedure, which was rated based on the qNOx score, showed a significant increase in the Macintosh blade group with a p-value of 0.003. The postoperative pain scale (VAS) was smaller in the McCoy blade group compared to the Macintosh group (p-value <0.001). Conclusion: The ability to use both laryngoscopes at some levels of Anesthesia residents was equally good, and the use of McCoy Blade is more effective than Macintosh Blade in the intubation laryngoscopy procedure.

To compare the haemodynamic stress response of direct laryngoscopy and oro-tracheal intubation using McCoy and Macintosh blade in general anaesthesia

Background: Direct Laryngoscopy and intubation lead to extensive stress response and sympathetic stimulation in the body which can be critical for some patient subsets like cardiac ischemia, raised intracranial tension, cerebral aneurysm, open globe injury, glaucoma etc. Hence reduction of the intense stress response is of utmost importance for a stable and safe hemodynamics in those patients. Aims and Objectives: 1. To find out the hemodynamic stress response exerted by the Macintosh blade and McCoy blade. 2. To compare the hemodynamic stress responses between the two blades. Materials and Methods: In this study we had selected 60(male and female in equal number) ASA grade-1 and grade- 2 patients posted for elective general surgery. They were randomly divided into two groups - group 1(laryngoscopy done by McCoy blade)and group 2(laryngoscopy done by Macintosh blade). Systolic Blood Pressure, Diastolic Blood Pressure , Mean Blood Pressure and Heart Rate were recorded before and after anaesthesia induction, just after intubation and one, three and six minutes after orotracheal intubation. Results: The results were compared over time between the two groups. Mean values of Systolic Blood Pressure, Diastolic Blood Pressure, Mean Blood Pressure and heart rate were significantly higher in group 2 as compared to group 1(with p values as 0.009, 0.008, 00.004 and 0.000 respectively). Conclusion: Thus we conclude that the stress response was significantly higher when laryngoscopy was done with Macintosh blade as compared with McCoy blade. We would also like to stress that the art of laryngoscopy should just not be mastered but all anaesthesiologists should think of and practise techniques which would make laryngoscopy smooth and less stressful for our patients. Intubation with McCoy laryngoscope blade is one such technique.

A Comparison of a Standard Macintosh Blade Laryngoscope, Pentax-AWS Videolaryngoscope and Intubrite Videolaryngoscope for Tracheal Intubation in Manikins in Sitting and Prone Positions: A Randomized Cross-Over Study

Background: Intubation of a patient in different positions may be done not only in emergency settings, but also in routine anesthesia (e.g., prone position for lumbar spine surgery). Methods: The aim of the study was to compare the classic Macintosh blade laryngoscope with two videolaryngoscopes: the Pentax-AWS and the Intubrite in a simulated scenario of a manikin placed in a sitting and prone position. Additionally, intubation with the use of all three devices was performed in a standard supine position as the control group. The time of intubation and the pressure exerted on the tongue was assessed. The ANOVA Friedman (analysis of variance) and Wilcoxon with Bonferroni correction tests were used for statistical analysis. Results: The time of intubation in a prone position was significantly shorter for the Pentax-AWS videolaryngoscope compared to the Macintosh and the Intubrite. There were no significant differences in the obtained results of the evaluated devices in sitting and standard positions. The lowest pressure exerted on the tongue was with the Pentax-AWS, followed by the Intubrite and the Macintosh laryngoscopes. Conclusions: The use of the Pentax-AWS was associated with faster tracheal intubation, creating lower pressure on tongue when compared with standard Macintosh and Intubrite laryngoscopes in both prone and sitting positions.

Hemodynamic responses to laryngoscopy and intubation using Macintosh, Miller and McCoy blades

Background: Direct Laryngoscopy and endotracheal intubation are essential components of administration of general anaesthesia but trigger major stress response, in the form of in­creased catecholamines leading to tachycardia and hypertension. This study is designed to compare the haemodynamic stress response with the Macintosh, McCoy and Miller blades. Methods: This prospective comparative study was conducted in 150 ASA grade I and II pa­tients, undergoing laparoscopic cholecystectomy under general anaesthesia from March 2017, were randomly divided into three groups using Macintosh, McCoy and Miller blade for endotracheal intubation respectively. Results: The groups were also comparable in respect to gender, mean age, ASA grade, Cor­mack and Lehane grade, Laryngoscopic intubation time, baseline heart rate, heart rate before laryngoscopy, baseline mean arterial pressure and Mean Arterial Pressure before laryngos­copy. The mean heart rates at end of 1, 3 and 5 minute were 93.58±13.11, 88.28±11.57 and 83.64±10.94 bpm with Macintosh blade; 93.08±12.09, 94.54±11.87 and 87.50±10.72 bpm with McCoy blades; 108.20±13.94, 95.18±12.75 and 93.22±12.32 bpm with Miller blades. Rise in heart rate as well as mean arterial pressure following intubation was greatest with Miller blade, followed by Macintosh blade and least with McCoy blade and was statistically significant (P< 0.01). Conclusions: Miller blade produced maximum haemodynamic stress response, followed by Macintosh blade and McCoy blade produced the least haemodynamic response, hence the latter is preferable when less haemodynamic response is desired.

Comparing Four Video Laryngoscopes and One Optical Laryngoscope with a Standard Macintosh Blade in a Simulated Trapped Car Accident Victim

Background. Tracheal intubation still represents the “gold standard” in securing the airway of unconscious patients in the prehospital setting. Especially in cases of restricted access to the patient, video laryngoscopy became more and more relevant. Objectives. The aim of the study was to evaluate the performance and intubation success of four different video laryngoscopes, one optical laryngoscope, and a Macintosh blade while intubating from two different positions in a mannequin trial with difficult access to the patient. Methods. A mannequin with a cervical collar was placed on the driver’s seat. Intubation was performed with six different laryngoscopes either through the driver’s window or from the backseat. Success, C/L score, time to best view (TTBV), time to intubation (TTI), and number of attempts were measured. All participants were asked to rate their favored device. Results. Forty-two physicians participated. 100% of all intubations performed from the backseat were successful. Intubation success through the driver’s window was less successful. Only with the Airtraq® optical laryngoscope, 100% success was achieved. Best visualization (window C/L 2a; backseat C/L 2a) and shortest TTBV (window 4.7 s; backseat 4.1 s) were obtained when using the D-Blade video laryngoscope, but this was not associated with a higher success through the driver’s window. Fastest TTI was achieved through the window (14.2 s) when using the C-MAC video laryngoscope and from the backseat (7.3 s) when using a Macintosh blade. Conclusions. Video laryngoscopy revealed better results in visualization but was not associated with a higher success. Success depended on the approach and familiarity with the device. We believe that video laryngoscopy is suitable for securing airways in trapped accident victims. The decision for an optimal device is complicated and should be based upon experience and regular training with the device.

Prospective Trial to Compare Direct and Indirect Laryngoscopy Using C-MAC PM® with Macintosh Blade and D-Blade® in a Simulated Difficult Airway

Objective. Evaluation of C-MAC PM® in combination with a standard Macintosh blade size 3 in direct and indirect laryngoscopy and D-Blade® in indirect laryngoscopy in a simulated difficult airway. Primary outcome was defined as the best view of the glottic structures. Secondary endpoints were subjective evaluation and assessment of the intubation process. Methods. Prospective monocentric, observational study on 48 adult patients without predictors for difficult laryngoscopy/tracheal intubation undergoing orthopedic surgery. Every participant preoperatively received a cervical collar to simulate a difficult airway. Direct and indirect laryngoscopy w/o the BURP maneuver with a standard Macintosh blade and indirect laryngoscopy w/o the BURP maneuver using D-Blade® were performed to evaluate if blade geometry and the BURP maneuver improve the glottic view as measured by the Cormack-Lehane score. Results. Using a C-MAC PM® laryngoscope, D-Blade® yielded improved glottic views compared with the Macintosh blade used with either the direct or indirect technique. Changing from direct laryngoscopy using a Macintosh blade to indirect videolaryngoscopy using C-MAC PM® with D-Blade® improved the Cormack-Lehane score from IIb, III, or IV to I or II in 31 cases. Conclusion. The combination of C-MAC PM® and D-Blade® significantly enhances the view of the glottis compared to direct laryngoscopy with a Macintosh blade in patients with a simulated difficult airway. Trial Registration Number. This trial is registered under number NCT03403946.