The changes of endotracheal tube intracuff pressures after ear and head and neck surgery-related positions: a prospective observational study / Alterações na pressão intracuff do tubo endotraqueal após posições cirúrgicas nas cirurgias de orelha e cabeça e pescoço: estudo observacional prospectivo

Abstract Introduction The cuff of an endotracheal tube seals the airway to facilitate positive-pressure ventilation and reduce subglottic secretion aspiration. However, an increase or decrease in endotracheal tube intracuff pressure can lead to many morbidities. Objective The main purpose of this study is to investigate the effect of different head and neck positions on endotracheal tube intracuff pressure during ear and head and neck surgeries. Methods A total of 90 patients undergoing elective right ear (Group 1: n = 30), left ear (Group 2: n = 30) or head and neck (Group 3: n = 30) surgery were involved in the study. A standardized general anesthetic was given and cuffed endotracheal tubes by the assistance of video laryngoscope were placed in all patients. The pilot balloon of each endotracheal tube was connected to the pressure transducer and standard invasive pressure monitoring was set to measure intracuff pressure values continuously. The first intracuff pressure value was adjusted to 18.4 mmHg (25 cm H2O) at supine and neutral neck position. The patients then were given appropriate head and neck positions before related-surgery started. These positions were left rotation, right rotation and extension by under-shoulder pillow with left/right rotation for Groups 1, 2 and 3, respectively. The intracuff pressures were measured and noted after each position, at 15th, 30th, 60th, 90th minutes and before the extubation. If intracuff pressure deviated from the targeted value of 20-30 cm H2O at anytime, it was set to 25 cm H2O again. Results The intracuff pressure values were increased from 25 to 26.73 (25-28.61) cm H2O after left neck rotation (p = 0.009) and from 25 to 27.20 (25.52-28.67) cm H2O after right neck rotation (p = 0.012) in Groups 1 and 2, respectively. In Group 3, intracuff pressure values at the neutral position, after extension by under-shoulder pillow and left or right rotation were 25, 29.41 (27.02-36.94) and 34.55 (28.43-37.31) cm H2O, respectively. There were significant differences between the neutral position and extension by under-shoulder pillow (p < 0.001), and also between neutral position and rotation after extension (p < 0.001). However, there was no statistically significant increase of intracuff pressure between extension by under-shoulder pillow and neck rotation after extension positions (p = 0.033). Conclusion Accessing the continuous intracuff pressure value measurements before and during ear and head and neck surgeries is beneficial to avoid possible adverse effects/complications of surgical position-related pressure changes.

Resumo Introdução O manguito ou cuff de um tubo endotraqueal sela as vias aéreas para facilitar a ventilação com pressão positiva e reduzir a aspiração de secreção subglótica. Entretanto, o aumento ou diminuição da pressão intracuff do tubo endotraqueal pode levar a muitas morbidades. Objetivo Investigar o efeito de diferentes posições da cabeça e pescoço da pressão intracuff do tubo endotraqueal durante cirurgias de orelha e cabeça e pescoço. Método Participaram do estudo 90 pacientes submetidos à cirurgia eletiva na orelha direita (Grupo 1: n = 30), orelha esquerda (Grupo 2: n = 30) ou cabeça e pescoço (Grupo 3: n = 30). Um anestésico geral padronizado foi administrado e o tubo endotraqueal com cuff foi colocado em todos os pacientes através de videolaringoscopia. O balão-piloto de cada tubo endotraqueal foi conectado ao transdutor de pressão e o monitoramento-padrão da pressão invasiva foi estabelecido para medir continuamente os valores da pressão intracuff. O primeiro valor de pressão intracuff foi ajustado para 18,4 mmHg (25 cm H2O) na posição supina e neutra do pescoço. Em seguida, os pacientes foram colocados nas posições cirúrgicas apropriadas de cabeça e pescoço antes do início da cirurgia. Essas posições foram rotação esquerda, rotação direita e extensão por rotação esquerda/direita com almofada sob o ombro, para os grupos 1, 2 e 3, respectivamente. As pressões intracuff s foram medidas e anotadas após cada posição, aos 15, 30, 60, 90 minutos e antes da extubação. Se a pressão intracuff saísse do valor desejado de 20 ~ 30 cm H2O a qualquer momento, ela era definida em 25 cm H2O novamente. Resultados Os valores de pressão intracuff aumentaram de 25 para 26,73 (25-28,61) cm H2O após a rotação do pescoço para a esquerda (p = 0,009) e de 25 a 27,20 (25,52-28,67) cm H2O após rotação do pescoço para a direita (p = 0,012) nos grupos 1 e 2, respectivamente. No Grupo 3, os valores da pressão intracuff na posição neutra, após extensão com almofada sob o ombro e rotação para a esquerda ou direita, foram 25, 29,41 (27,02-36,94) e 34,55 (28,43-37,31) cm H2O, respectivamente. Houve diferenças significativas entre a posição neutra e a extensão com almofada sob o ombro (p < 0,001) e também entre a posição neutra e a rotação após a extensão (p < 0,001). Entretanto, não houve aumento estatisticamente significante da pressão intracuff entre extensão com almofada sob o ombro e rotação do pescoço após as posições de extensão (p = 0,033). Conclusão As medições contínuas do valor da pressão intracuff antes e durante cirurgias de orelha e cabeça e pescoço são benéficas para evitar possíveis efeitos adversos/complicações de alterações de pressão relacionadas à posição cirúrgica.

Effect of nitrous oxide on cuff pressure of ProSeal laryngeal mask airway during pediatric anesthesia / 上海第二医科大学学报

Objective To evaluate the effect of nitrous oxide(N2O) on the cuff pressure of ProSeal laryngeal mask airway(PLMA) in pediatric anesthesia. Methods Thirty-two pediatic patients were enrolled and divided into two groups randomly.PLMA cuffs were inflated with air(Group A) or 50% N2O/oxyen(Group N) to 20 mmHg as initial pressure.The intracuff pressure was monitored during anesthesia with 50% N2O in oxygen. Results Intracuff pressure increased to(40.6?9.3) mmHg in Group A and slightly decreased in Group N.Deflation volume in Group A was much more than that in Group N[(4.4?2.3) mL vs(2.6?1.0) mL,P

Clinical Survey of Appropriate Cuff Volume and Pressure during General Anesthesia in Pediatric Patients / 대한구급학회지

BACKGROUND: Uncuffed endotracheal tubes are commonly used in pediatrics even when the risk of gastric aspiration is significant. But cuffed endotracheal tubes effectively protect the risk of pulmonary aspiration and completely seal the airway. This study was designed to determine the appropriate cuff volume and pressure with low risk of ischemic injury to children's airway. METHODS: We intubated cuffed endotracheal tube (internal diameter 4.5, 5.0, 5.5 mm) in 90 surgical pediatric patient from 16 to 118 months of age. After intubation, initial cuff volume and pressure were measured at the level of complete sealing in each group. Each group was administrated 50% nitrous oxide and 67% nitrous oxide and measured cuff pressure at 20 minutes, 40 minutes. RESULTS: 1) The mean initial cuff volume and pressure of 4.5 ID tube were 0.59 +/- 0.16 ml and 14.5 +/- 0.31 cmH2O (n=30). 2) The mean initial cuff volume and pressure of 5.0 ID tube were 1.00 +/- 0.38 ml and 14.3 +/- 3.55 cmH2O (n=30). 3) The mean initial cuff volume and pressure of 5.5 ID tube were 1.06 +/- 0.26 ml and 14.28 +/- 2.01 cmH2O (n=30). 4) The cuff pressure increased significantly in the course of time, but no pressure in three groups was above 30 cmH2O. CONCLUSIONS: We could determine the appropriate cuff volume of cuffed endotracheal tube in pediatric patients. Also we concluded that nitrous oxide concentration affect little intracuff pressure in brief operation.

The Study of Appropriate Sizes in Large-Volume, Low-Pressure Cuffed Tubes in Adults under General Anesthesia: With special reference to intracuff pressure changes / 대한마취과학회지

Although cuffed tracheal tubes are available in various sizes(ranging from 5 to 11 mm I.D.), many anesthesiologists are apt to use a limited range of sizes in adult patients. In making a selection, we prefer the ease of insertion of a smaller tube and the better gas flow characteristics of a larger tube. However, when the tube in small perimeter of cuff or over-large cuffed tube is selected to seal the trachea, intracuff pressure exceeds tracheal capillary perfusion pressure and results in tracheal complication during prolonged general anesthesia with N2O-O2 mixture. This study was performed to determine the appropriate size of tubes for men(Group A, n=30) and women(Group B, n=30), using the large-volume, low-pressure cuffed tubes(Portex-Blue Line Tubes, U.K.) during prolonged general anesthesia with N2O-O2 mixture. They were subdivided into A-l(7.5 mm I.D.), A-2(8.0 mm I.D.), A-3(8.5 mm I.D.) in men and B-l(6.5 mm I.D.), B-2(7.0 mm I.D.), B-3(7.5 mm I.D.) in women. Each subgmup included 10 patients in number. They were compared in several factors; residual volume of each tube, sealing volume, sealing pressure and the intracuff pressure changes with time. The results were as follows 1) There were no significant differences in age, height, and weight among the subgroups in men and women respectively. 2) There were significant changes of intracuff pressure every 20 minutes in both groups and the changes of slope of pressure were significantly steep in 7.5 mm I.D. in men and 6.5 mm I.D. in women. 3) Although the values of sealing pressure of all groups were less than 22 mmHg, the intracuff pressure were increased and maintained over 22 mmHg after 100 minutes in 7.5 mm I.D. in men and 20 minutes in 6.5 mm I.D. in women. 4) The changes in volumes(delta V) after 2 hours among 6 subgroups were not statistically significant, but the changes in pressures(delta P) were higher in 7.5 mm I.D.in men and 6.5 mm I.D. in women. 5) According to Spearman's Correlation Coeffients, the smaller the residual volume of tube, the higher the sealing pressure to seal the trachea and the larger the pressure changes to volume changes. In conclusion, intracuff pressure of 7.5 mm I.D. in men and that of 6.5 mm 1.D. in women can easily exceed the tracheal capillary perfusion pressure during prolonged general anesthesia with N2O-O2 mixture and when considering the changes of intracuff pressure alone, it seems that 8.0, 8.5 mm I.D. in men and 7.0, 7.5 mm I.D. in women are preferable to seal the trachea.

Endotracheal Tube Cuff Volume and Pressure Changes in the Use of Nitrous Oxide / 대한마취과학회지

The development of endotracheal tubes with high-volume and low-pressure cuffs has decreas ed the incidence of associated tracheal injury. If room air used for inflation of the cuff during general anesthesia using N2O-O2, mixtures, however, endotracheal tube cuff result in distention and potential pressure changes. Therefore, tracheal pressure injury may occur during long general anesthesia(especially, head and neck surgery). For the prevention of this problems and the determination of proper methods, we performed this study relating to nitrous oxide diffusion into a gas filled endotracheal tube cuff.

Regulation of Endotracheal Cuff Pressure / 대한마취과학회지

A few postulated methods of regulating cuff pressure (filling anesthetic gas in the cuff, filling saline in the cuff, connecting cuff to a pressure regulating device) were compared each other after determining compliance curve of cuffs. Although there were no significant difference among slopes of linear regression curve of compliance curves of each condition, pressure range, standard deviation were most acceptable with the use of a pressure regulating device.