Cuffed Tracheal Tubes in Children - Myths and Department of Anaesthesia University Children s Hospital Zurich Switzerland
PRO Reduced gas leak, low fresh gas flow Decreased atmospheric pollution Constant controlled ventilation Improved efficiency of ventilation Reliable monitoring of endtidal co 2 and anaesthetic gases Improved accuracy of tidal volume and lung compliance monitoring
Cuffed Tracheal Tubes In Children PRO Compensation for different sized tracheas Compensation for different shaped tracheas Reduction in the requirement to change the tube Decreased risk of pulmonary aspiration Decreased use of too large uncuffed tubes Decreased pressure exerted on the cricoid
PRO Tracheal Tube cuffed uncuffed Post-operative operative Croup 2.4 % 2.9 % Tube Exchange 1 % 23 % FGF > 2 liter/min 1 % 11 % N2O > 10 ppm 0 % 37 % Khine HK - Anesthesiology 1997
CON No Cuff Required In Children < 8 years Laryngo-tracheal injuries Inadvertent Cuff Over-Inflation Inadequate Designed Paediatric Tube Cuffs Smaller Internal Tube Diameter Increased Costs Not The (G)old Standard!
Yes or No? Democratic Medicine (APA 2002) 2/3 Con 1/3 Pro Hatch 2002: It Is Not Forbidden To Use Cuffed Endotracheal Tubes in Children... Not Evidence-Based Medicine!!!
Myths Cuffed Tubes Are Not Needed in Children Because The Circular Cricoid Seals The Tracheal Tube
Myths and Adult Larynx
Myths and Infantile Larynx Eckenhoff JE - Anesthesiology 1954
Myths Cuffed Tracheal Tubes In Children Are A Major Reason For Airway Injurys
Reasons for Airway Injury in Children Too Large Endotracheal Tube Traumatic Intubation Repeated Intubation Attempts Repeated Tracheal Tube Exchange
Reasons for Airway Injury in Children Prolonged Intubation Inadequate Tube Fixation (oral/nasal) Inadequate Sedation Insufficient Tissue Perfusion Local Infection
Free Air Cuff Hyperinflation Free air inflation results in variable cuff pressure with hyperinflation in 39% of cases. Free inflation of the tracheal tube cuff, controlled only by the palpation of the pilot balloon, is not reliable and results in extremely variable (and sometimes very high) initial cuff pressures in children. Felten ML - Anesth Analg 2003
Nitrous Oxide and Cuff Hyperinflation time (min) 50 45 40 35 30 25 20 15 10 5 0 A/B C Gas Removal for Cuff Pressure Release During Nitrous Oxide Exposure (Set 20 cm H 2 O / Limit 25 cm H 2 O) A/B A/B 1 2 3 4 5 gas removal (No) A/B A/B Dullenkopf A, Gerber AC, Weiss M - Canadian Journal of Anesthesia 2004
Myths Cuffed Tracheal Tubes Are Inadequately Designed
Inadequate Depth marks Ho AMH, Aun CST, Karmakar MK. The margin of safety associated with the use of cuffed paediatric tracheal tubes. Anaesthesia 2002; 57: 169-182 Goel S, Lim SL. The intubation depth marker: the confusion of the black line. Paediatric Anaesthesia 2003; 13: 579-583 Wallace CJ, Bell Graham TB. Tracheal tube markings. Pediatric Anesthesia 2004; 14: 283-285
Outer diameter (OD) Cuffed Tracheal Tubes In Children Inadequate Design ID Tracheal tube brand No Cuff 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 (mm) Sheridan Tracheal Tube uncuffed Murphy 1-3.6 (3.6) 4.3 (4.2) 4.9 (4.9) 5.5 (5.5) 6.2 (6.2) 6.8 (6.8) 7.5 (7.5) 8.2 (8.2) 8.8 (8.8) 9.6 (9.6) Sheridan Tracheal Tube cuffed Murphy 2 + NA 4.2 (4.2) 4.9 (4.9) 5.5 (5.5) 6.2 (6.2) 6.8 (6.8) 7.5 (7.5) 8.2 (8.2) 8.8 (8.8) 9.6 (9.6) Sheridan Tracheal Tube cuffed Magill 3 + NA 4.3 (4.2) NA 5.5 (5.5) NA 6.9 (6.8) NA 8.1 (8.2) 8.9 (8.8) 9.4 (9.6) Mallinckrodt TT Contour 4-3.7 (3.6) 4.4 (4.3) 5.0 (4.9) 5.7 (5.6) 6.2 (6.2) 6.9 (6.9) 7.6 (7.5) 8.1 (8.2) 8.8 (8.9) 9.6 (9.6) Mallinckrodt TT High Contour Murphy 5 + NA 4.4 (4.3) 4.9 (4.8) 5.7 (5.6) 6.3 (6.2) 7.0 (6.9) 7.6 (7.5) 8.2 (8.2) 8.9 (8.8) 9.5 (9.6) Mallinckrodt TT High Contour Murphy P-Serie 6 + NA 4.3 (4.3) 5.0 (4.9) 5.7 (5.6) 6.4 (6.2) 6.7 (6.9) 7.7 (7.5) 8.1 (8.2) 8.9 (8.8) 9.4 (9.6) Mallinckrodt TT Lo Contour Magill 7 + NA 4.5 (4.3) 4.9 (4.8) 5.7 (5.6) 6.2 (6.2) 6.9 (6.9) 7.5 (7.5) 8.3 (8.2) 9.0 (8.8) 9.8 (9.6) Mallinckrodt TT Lo Contour Murphy 8 + NA 4.4 (4.3) 5.0 (4.8) 5.6 (5.6) 6.2 (6.2) 7.0 (6.9) 7.5 (7.5) 8.2 (8.2) 8.8 (8.8) 9.4 (9.6) Mallinckrodt TT Hi-Lo Murphy 9 + NA NA NA NA NA 6.9 (6.9) 7.5 (7.5) 8.1 (8.2) 8.8 (8.8) 9.4 (9.6) Mallinckrodt TT Safety Flex 10 + NA 5.2 (5.0) 5.5 (5.2) 6.2 (6.2) 6.7 (6.7) 7.2 (6.9) 7.9 (7.5) 8.5 (8.2) 9.2 (8.8) 9.8 (9.6) Portex TT - Blue Line, Magill, uncuffed 11-3.4 (3.5) 4.2 (4.2) 4.8 (4.8) 5.5 (5.5) 6.1 (6.2) 6.8 (6.9) 7.5 (7.6) 8.2 (8.2) 9.0 (8.9) 9.7 (9.6) Portex TT - Profile Soft Seal Cuff, Murphy 12 + NA NA NA NA NA 7.0 (6.9) 7.6 (7.6) 8.3 (8.2) 8.8 (8.9) 9.6 (9.6) Rüsch Ruschelit Safety Clear 13-3.4 (3.3) 4.0 (4.0) 4.8 (4.7) 5.3 (5.3) 6.0 (6.0) 6.7 (6.7)** 7.3 (7.3) 8.0 (8.0) 8.8 (8.9) 9.4 (9.3) Rüsch Ruschelit Super Safety Clear Magill 14 + 4.0 (4.0) 5.1 (5.0) 5.3 (5.3) 5.9 (6.0) 6.2 (6.3) 6.7 (6.7)** 7.2 (7.3) 8.0 (8.0) 8.7 (8.7) 9.0 (9.0) Rüsch Ruschelit Super Safety Clear Murphy 15 + NA NA NA NA NA 6.7 (6.7) 7.3 (7.3) 8.0 (8.0) 8.8 (8.7) 9.2 (9.0) ID (mm) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Tracheal diameters and PCETT ID Age related PCETT ID according to the formula of Khine 4 Age related 95 % range of internal tracheal diameter (mm) 20,21 Age related 95 % range of internal tracheal diameter (mm) 20,22 Age related PCETT ID according to the formula of Motoyama 19 Age related 95 % range of internal tracheal diameter (mm) 20,21 Age related 95 % range of internal tracheal diameter (mm) 20,22 Premature Neonate Premature Neonate Fullterm Neonate 3.6-7.8 3.5 8.2 Fullterm Neonate 3.6 7.8 3.5 8.2 1 year 3 years 5 year 7 years 9 years 11 years 13 years 15 years 4.1 8.3 3.9 8.8 5.2 9.5 4.7 9.9 6.3 10.6 5.5 11.1 7.4 11.7 6.3 12.2 8.5 12.8 7.1 13.3 9.6 13.9 7.9 14.5 10.8 15.0 8.7 15.6 11.9 16.3 9.5 16.7 1 year 2 year 4 year 6 years 8 years 10 years 12 years 14 years 4.1 8.3 3.9 8.8 4.7 8.9 4.3 4.9 5.8 9.8 5.1 10.5 6.9 11.1 5.9 11.6 8.0 12.2 6.7 12.8 9.1 13.3 7.5 13.9 10.2 14.4 8.3 15.0 11.3 15.5 9.1 16.2 Weiss M - British Journal of Anaesthesia 2004
Distances A/C/D (mm) Tracheal diameters and PCETT ID Inadequate Design ID Tracheal tube brand No Cuff 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Sheridan Tracheal Tube uncuffed Murphy 1 -/-/21 -/-/22 -/-/24 -/-/27 -/-/29 -/-/31 -/-/31 -/-/35 -/-/37 -/-/41 Sheridan Tracheal Tube cuffed Murphy 2 + NA 12/25/- 13/32/- 13/32/- 15/35/- 20/42/- 20/46/- 21/48/- 23/55/- 25/60/- Sheridan Tracheal Tube cuffed Magill 3 + NA 10/23/- NA 10/27/- NA 12/35/- NA 14/40/- 14/47/- 16/50/- Mallinckrodt TT Contour 4 -/-/30 -/-/30 -/-/30 -/-/30 -/-/30 -/-/29 -/-/30 -/-/29 -/-/31 -/-/31 Mallinckrodt TT High Contour Murphy 5 + NA 14/26/- 13/26/- 16/30/- 19/37/- 20/40/- 20/44/- 21/51/- 21/49/- 26/54/- Mallinckrodt TT High Contour Murphy P-Serie 6 + NA 13/24/42 16/29/50 17/30/49 22/39/57 20/37/59 22/43/62 18/40/60 24/49/67 19/46/67 Mallinckrodt TT Lo Contour Magill 7 + NA 11/21/- 11/23/- 12/27/- 12/29/- 12/43/- 17/50/- 17/50/- 17/50/- 19/60/- Mallinckrodt TT Lo Contour Murphy 8 + NA 14/24/- 16/27/- 15/29/- 18/36/- 19/49/- 21/53/- 21/54/- 24/57/- 26/66/- Mallinckrodt TT Hi-Lo Murphy 9 + NA NA NA NA NA 19/46/- 19/47/- 18/48/- 19/51/- 20/53/- Mallinckrodt TT Safety Flex 10 + NA 10/21/42 11/26/44 11/26/47 12/30/53 17/45/68 15/50/70 18/50/70 18/52/72 18/56/80 Portex TT - Blue Line, Magill, uncuffed 11 - -/19/22 -/21/27 -/21/32 -/22/37 -/21/42 -/22/47 -/21/52 -/22/59 -/-/- -/-/- Portex TT - Profile Soft Seal Cuff, Murphy 12 + NA NA NA NA NA 20/42/76 21/45/79 23/53/84 22/51/85 24/58/92 Rüsch Rüschelit Safety Clear 13 - -/-/20 -/-/20 -/-/21 -/-/30 -/-/30 -/-/40 -/-/39 -/-/40 -/-/41 -/-/- Rüsch Rüschelit Super Safety Clear Magill 14 + 9/21/36 12/28/40 11/30/44 14/33/47 13/32/48 17/42/70 16/42/70 16/48/79 18/52/80 18/54/84 Rüsch Rüschelit Super Safety Clear Murphy 15 + NA NA NA NA NA 21/47/76 20/47/76 22/55/82 23/57/84 25/63/88 ID (mm) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Age related PCETT ID according to the formula of Khine 4 Age-related 95 % range of tracheal length (mm) 20,21 Tracheal length (mm) 23 Age related PCETT ID according to the formula of Motoyama 19 Age-related 95 % range of tracheal length (mm) 20,21 Tracheal length (mm) 23 Premature Neonate Premature Neonate Fullterm Neonate 39.4-60.5 40 Fullterm Neonate 39.4-60.5 40 1 year 3 year 5 year 7 years 9 years 11 years 12 years 15 years 43.0 65.8 45 50.2 76.4 53 57.4 87.1 56 64.6 97.7 59 71.8 108.3 61 78.9-119 86.1 129.6 93.3 140.2 1 year 2 year 4 year 6 years 8 years 10 years 12 years 14 years 43.0 65.8 45 46.6 71.1 50 53.8 81.8 54 61.0 92.4 57 68.2 103.0 60 75.4 113.7 63 82.5 124.5 89.7 134.9
Inadequate Design ID Tracheal Tube Brand No Cuff 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Cuff diameter (mm) at 20 H 2 O cuff pressure Cross-sectional cuff area (mm 2 )at 20 cm H 2 O cuff pressure Tracheal diameters and PCETT ID Sheridan Tracheal Tube cuffed Murphy 2 + NA 7.0 (7.3) 8.8 (8.9) 8.8 (8.9) 11 (11) 13 (13) 16 (16) 16 (16) 19 (19) 19 (19) Sheridan Tracheal Tube cuffed Magill 3 + NA 7.1 (7.3) NA 8.5 (8.9) NA 13 (13) NA 16 (16) 18 (19) 18 (19) Mallinckrodt TT High Contour Murphy 5 + NA 6 (6) 7 (7) 8 (8) 11 (11) 20 (18) 21 (21) 23 (22) 24 (23) 28 (25) Mallinckrodt TT High Contour Murphy P-Serie 6 + NA 6.5 (6) 7 (7) 8 (8) 12 (12) 20 (18) 22 (21) 23 (22) 24 (23) 28 (25) Mallinckrodt TT Lo Contour Magill 7 + NA 6 (6) 7 (7) 8 (8) 11 (11) 17 (17) 19 (19) 21 (21) 22 (22) 24 (24) Mallinckrodt TT Lo Contour Murphy 8 + NA 6 (6) 7 (7) 8 (8) 11 (11) 17 (17) 19 (19) 21 (21) 22 (22) 24 (24) Mallinckrodt TT Hi-Lo Murphy 9 + NA NA NA NA NA 20.5 (20) 21 (21) 23 (23) 25 (25) 28 (28) Mallinckrodt TT Safety Flex 10 + NA 7 (6) 8 (7) 9 (8) 11 (11) 17 (17) 19 (19) 21 (21) 22 (22) 24 (24) Portex TT - Profile Soft Seal Cuff, Murphy 12 + NA NA NA NA NA 16 (17) 17 (17) 23 (23) 23 (23) 30 (30) Rüsch Rüschelit Super Safety Clear Magill 14 + 8 (8) 8 (8) 8 (8) 10 (10) 10 (11) 12 (13) 14.5 (16.5) 16.5 (18.5) 18.5 (20.5) 24 (24) Rüsch Rüschelit Super Safety Clear Murphy 15 + NA NA NA NA NA 11 (13) 16.5 (16.5) 16 (18.5) 20.5 (20.5) 23 (24) Sheridan Tracheal Tube cuffed Murphy 2 + NA 42 62 62 95 133 201 201 283 283 Sheridan Tracheal Tube cuffed Magill 3 + NA 42 NA 62 NA 133 NA 201 283 283 Mallinckrodt TT High Contour Murphy 5 + NA 28 38 50 95 254 346 380 415 491 Mallinckrodt TT High Contour Murphy P-Serie 6 + NA 28 38 50 113 254 346 380 415 491 Mallinckrodt TT Lo Contour Magill 7 + NA 28 38 50 95 227 283 346 380 452 Mallinckrodt TT Lo Contour Murphy 8 + NA 28 38 50 95 227 283 346 380 452 Mallinckrodt TT Hi-Lo Murphy 9 + NA NA NA NA NA 314 346 415 490 615 Mallinckrodt TT Safety Flex 10 + NA 28 38 50 95 227 283 346 380 452 Portex TT - Profile Soft Seal Cuff, Murphy 12 + NA NA NA NA NA 201 227 415 415 707 Rüsch Rüschelit Super Safety Clear Magill 14 + 8 (50) 50 50 79 95 133 214 269 330 452 Rüsch Rüschelit Super Safety Clear Murphy 15 + NA NA NA NA NA 133 214 269 330 452 ID ( mm) 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Age related PCETT ID according to the formula of Khine 4 Premature Neonate Neonate to 1 st birthday 1 to 3 rd birthday 3 to 5 th birthday 5 to 7 th birthday 7 to 9 th birthday 9 to 11 th birthday 11 to 13 th birthday 13 to 15 th birthday Maximal (95%) age-related internal tracheal diameter (mm) 20,21 8.3 9.5 10.6 11.7 12.8 13.9 15.0 16.3 17.3 Maximal (95%) age-related cross-sectional tracheal area (mm 2 ) 20,22 Age related PCETT ID according to the formula of Motoyama 19 Premature Neonate 15 to 16 th birthday 47.1 63.6 81.7 102.0 124.6 149.5 176.6 206.0 234.9 Neonate to 1 st birthday 1 to 2 nd birthday 2 to 4 th birthday 4 to 6 th birthday 6 to 8 th birthday 8 to 10 th birthday 10 to 12 th birthday 12 to 14 th birthday Maximal (95%) age-related internal tracheal diameter (mm) 20,21 8.3 8.9 10 11.1 12.2 13.3 14.4 15.7 17.3 Maximal (95%) age-related cross-sectional tracheal area (mm 2 ) 20,22 14 to 16 th birthday 47.1 55.4 72.3 91.6 113.0 136.8 162.8 191.0 234.9
Injury Due To Wrong Tube Cuff Design 11 months old boy Cardiac surgical procedure with cpb Tracheal intubation: ruesch tt id 4.0 cuffless Unacceptable high air leak around the tube Tracheal intubation: ruesch tt id 4.0 with cuff Tight fit - small leak with active deflated cuff
Injury Due To Wrong Tube Cuff Design Cicu: : ventilation with active deflated cuff (2 days) Transfer to picu uch Cuff pressure set to ambient pressure Extubation 3 rd postoperative day Postextubation stridor Increasing oxygen requirements
Ideal Design of Cuffed Pediatric Tubes Cuff-Free Subglottic Tube Shaft No Murphy Eye Short High Volume - Low Pressure Cuff (HVLP) Adequately Positioned Depth Marking Minimal Thickness of The Cuff-Membrane Automatic Cuff Pressure Release Valve Recommendations for Age-Related Use
Ideal Design of Cuffed Pediatric Tubes Internal tube diameter (ID; mm) Age group (years) Smallest tracheal diameter of age group (mm) Outer tube diameter (OD; mm) Cuff diameter (mm) at 20 cm H2O cuff pressure Cross-sectional cuff area (mm 2 ) Largest internal tracheal area cross-sectional of age group (mm 2 ) Ratio of cuff-to-largest trachea lcross-sectional area (%) 3.0 Full term neonates to 1 st birthday year 3.6 4.1 10 78.5 35.3 222.4 3.5 1 year to 2 nd birthday 4.1 4.8 12 113.0 46.8 241.5 4.0 2 years to 4 th birthday 4.7 5.4 12 113.0 70 161.5 4.5 4 years to 6 th birthday 5.8 6.1 14 153.9 93.1 165.3 5.0 6 years to 8 th birthday 6.9 6.7 16 201.0 116.2 172.9 5.5 8 years to 10 th birthday 8 7.3 16 201.0 139.4 144.2 6.0 10 years to 12 th birthday 9.1 8.0 18 254.3 162.5 156.5 6.5 12 years to 14 th birthday 10.2 8.7 20 314.0 185.7 169.1 7.0 14 years to 16 th birthday 11.3 9.3 22 379.9 234.9 161.7 Weiss M, Dullenkopf, Gerber AC - Anaesthesist 2004
Microcuff Pediatric Tracheal Tube Mean Mean Mean Mean Mean Mean Mean Mean Mean ID Age Height Weight Leak P Seal P Lips Tip-Carina D Trachea L % Trachea Tube yrs cm kg cmh2o cmh2o cm dm cm % 3 0.4 60.9 6.7 12.4 9.9 10.0 2.3 4.7 51.3 3.5 1.4 78.8 10.5 12.5 9.8 11.6 2.8 5.5 50.1 4 2.9 93.9 13.9 8.6 10.0 12.9 3.1 6.1 49.8 4.5 4.9 107.9 17.6 8.6 9.7 13.7 3.3 6.7 51.9 5 6.9 120.8 23.6 8.0 9.6 14.9 3.3 7.1 54.4 5.5 8.9 131.3 27.6 8.8 9.7 15.7 3.6 8.1 55.8 6 11.0 144.5 39.0 7.2 9.6 16.4 3.9 8.9 56.7 6.5 13.0 153.8 44.7 7.8 9.5 17.4 4.3 9.7 56.5 7 15.0 165.3 56.9 6.1 9.6 18.4 5.1 10.9 53.9 Dullenkopf A, Gerber AC, Weiss M - European Journal of Anaesthesiology 2004; in press
Microcuff Pediatric Tracheal Tube Patients (%) 50 45 40 35 30 25 20 15 10 5 0 Frequency Distribution of Leak Pressures < 5 < 10 < 15 < 20 > 20 > 25 > 35 Leak Pressure Groups (cm H 2 O) All (%) Boys (%) Girls (%) Dullenkopf A, Gerber AC, Weiss M - Anesthesiology; submitted
Microcuff Pediatric Tracheal Tube Frequency Distribution of Sealing Pressures 40 35 All (% ) 30 25 20 15 Boys (%) Girls (%) 10 5 0 n Patients (%) 0 2 4 6 8 10 12 14 16 18 20 Sealing Pressures (cm H 2 O) Dullenkopf A, Gerber AC, Weiss M - Anesthesiology; submitted
Microcuff Pediatric Tracheal Tube Tracheal Tube Insertion based on Intubation Depth Marks (Children 0-16 years) 8 6 4 2 0-2 0 2 4 6 8 10 12 14 16 18 Age (years) Distance Tube Tip to Carina (cm) Dullenkopf A, Gerber AC, Weiss M - British Journal of Anaesthesia; submitted
Microcuff Pediatric Tracheal Tube Oral Tube Insertion Depth Correction to cm = 12 + (Age/2) (Children > 2 years) 8 6 4 2 0-2 0 2 4 6 8 10 12 14 16 18 Age (years) PD Dr. Markus Dullenkopf Weiss A, Gerber AC, Weiss M - British Journal of Anaesthesia; submitted Tube Tip Correction / Distance Tube Tip to Carina (cm)
Microcuff Pediatric Tracheal Tube Microcuff ID 4.0 mm Mallinckrodt ID 4.0 mm Rüesch ID 4.0 mm Sheridan ID 4.0 mm Picture: Comparison of 4 tracheal cuffed pediatric tubes Dullenkopf A, Gerber AC, Weiss M - Pediatric Anesthesia 2004
Microcuff Pediatric Tracheal Tube High Volume - Low Pressure Cuff Sealing Characteristics
Myths Smaller Diameters in Cuffed Tracheal Tubes Increase Work of Breathing and Cause Difficulties With Tracheal Suctioning
Smaller Diameters Not A Problem During IPPV or Pressure Support Rare Suctioning During Anaesthesia Problems In The ICU Problems In Tubes Sizes ID 3.0 and 3.5 mm
Myths Cuffed Tracheal Tubes Cause Increased Costs
Increased Costs 2-44 Times More Expensive Than Uncuffed Tubes Reduced Overall Costs by: Less Tube Exchange ( up to 28 % ) Less Fresh Gas Flow Consumption Less Volatile Anaesthetic Consumption No Enviromental Pollution (Health!) Other Advantages (ETCO2 Monitoring, Oxygenation, Loss of Time by Tube Exchange,... )
Myths There Is Limited Experience With Cuffed Tracheal Tubes In Small Children
Experience Large Experience from Single Centers Paris Zurich Lund Pittsburgh Limited Multi-Centre Experience Limited Randomised Prospective Studies
Myths Uncuffed Tracheal Tubes Are The GOLD Standard For Children Below 8 Years Of Age
Uncuffed Tracheal Tubes Becomes The OLD Standard For Children Below 8 Years Of Age
Conclusions Cuffed Tracheal Tubes Can Be Safely Used in Children: Air Leak Control (<20 cm H 2 0) Cuff Pressure Control (<20 cm H 2 0) Adequate Designed Cuffed Tubes