Background
Methods
Search strategy
Study selection
Inclusion criteria |
• Experimental and clinical studies |
• Intervention arm with high-volume, low-pressure (HVLP) polyurethane (PU)-cuffed endotracheal tube |
• Control group with HVLP conventional polyvinyl chloride (PVC)-cuffed endotracheal tube |
• Studies evaluating either fluid leakage or intubation-related respiratory infection (early-postoperative pneumonia, ventilator-associated tracheobronchitis, ventilator-associated pneumonia) |
• Article written in English or Dutch |
Exclusion criteria |
• Descriptive studies |
• Studies without a control group |
• Evidence of confounders in one of the study arms, such as the use of additional measures to reduce the risk of microaspiration (e.g., subglottic secretions drainage, taper-shaped cuff, gel lubrication of the cuff, positive end-expiratory pressure) or use of measures to prevent pneumonia (e.g., hand hygiene promotion, head-of-bed elevation) in only one of the study arms. Differences in cuff shape other than conical (taper-shaped) were not considered an exclusion criterion. As such, comparisons of cylindrical PU cuff vs. globular PVC cuffs were accepted. |
• Not original research (reviews, systematic reviews, meta-analysis, editorials, letters) |
• No full text available |
Data extraction and quality assessment
Results and discussion
Author, year | Materials tested | Experimental settings | Pcuff
| Fluid and leakage measurement | Experiment repetition | Main results |
---|---|---|---|---|---|---|
In vitro studies | ||||||
Dullenkopf, 2003 [8] | • 1 PU-cuffed ETT (MICROCUFF HVLP ICU; Microcuff GmbH, Heidelberg, Germany) • 4 PVC-cuffed ETTs (Portex Profile Soft Seal, SIMS Portex Ltd., Hythe, UK; Rüschelit Super Safety Clear, Rüsch GmbH, Kernen, Germany; Mallinckrodt Hi-Lo, Mallinckrodt Medical, Athlone, Ireland; Sheridan/CF, Hudson Respiratory Care, Temecula, USA) • ID all ETTs 7.5 mm | • Vertical PVC trachea model (ID 20 mm) • Unlubricated and lubricated cuffs • No ventilatory simulation | • 10, 15, 20, 25, 30, 60 cmH2O • Controlled by manometer | • Colored water (5 ml) • Amount of leaked fluid passed through tube cuff within 5, 10, and 60 minutes | 4 repetitions of 2 tubes of each brand | • Fluid leakage occurred in all PVC cuffs at Pcuff 10–60 cmH2O. In the PU cuff, leakage was recorded only at Pcuff 10 cmH2O (<5 minutes) and at Pcuff 15 cmH2O (<60 minutes) • PU cuffs sealed significantly better at conventional Pcuff (20–30 cmH2O) than with all types of PVC cuffs; while no leak was observed in PU cuffs, >90 % of the test fluid (>4.5 ml) passed through cuff in all PVC cuffs |
Lucangelo, 2008 [14] | • PU-cuffed ETT (Mallinckrodt SealGuard, Mallinckrodt Medical, Cornamady, Anthlone County, Ireland) • PVC-cuffed ETT (Mallinckrodt Hi-Lo, Mallinckrodt Medical, Cornamady, Anthione County, Ireland) • ID all ETTs 7.5 mm | • Room temperature • Vertical Pyrex cylindertrachea model, ID 25 mm • Unlubricated cuffs • 5-, 7.5-, and 10-cm PEP randomly applied • PEP removed after 30 minutes • Experiment lasted 1 h | • 30 cmH2O • Controlled by aneroid manometer | • Evans blue (1 ml) diluted with normal saline (1 ml) | Triplicate experiments with new ETTs | • 10 minutes after PEP removal (40 minutes after Evans blue dye application on top of cuffs), all liquid had passed through PVC cuffs • No leakage in PU cuffs |
Dave, 2010 [24] | • PU-cuffed ETTs (standard SealGuard, Covidien, Athlone, Ireland; MICROCUFF, Kimberley Clark, Zaventem, Belgium) • 3 PVC-cuffed ETT (Hi-Lo, Covidien, Athlone, Ireland; Portex Profile Soft Seal, SIMS Portex Ltd., Hythe, UK; Rüschelit Super Safety Clear, Rüsch GmbH, Kernen, Germany) ID all ETTs 7.5 mm | • Room temperature • Artificial PVC trachea model with variable ID 16, 20, 22 mm • Unlubricated cuffs • No ventilatory simulation, no PEEP | • 25 cmH2O • Controlled by digital automated manometer | • Clear water (5 ml) • Leakage measured at 5 minutes and 60 minutes | 8 tubes tested of each ETT type | PVC cuffs leaked considerably more than PU cuffs • At 5 minutes: - ID 16 and 20 mm: 0.03–1.62 ml (PU) vs. 4.27–4.67 ml (PVC) - ID 22 mm: 0–4.85 ml (PU) vs. 4.65–4.71 ml (PVC) • At 60 minutes: - ID 16 and 20 mm: 0.90–4.58 ml (PU) vs. 4.61–4.69 ml (PVC) - ID 22 mm: 0–4.85 ml (PU) vs. 4.65–4.75 ml (PVC) |
Dave, 2011 [13] | • PU-cuffed ETT (SealGuard, Covidien, Athlone, Ireland) • PVC-cuffed ETT (Hi-Lo, Covidien, Athlone, Ireland) ID all ETTs 5 mm | • Vertical artificial PVC trachea model, ID 22 mm • Unlubricated cuffs • Test lung attached to trachea model • Pressure-controlled ventilation with PIP 15, 20, 25 cmH2O • PEEP 5 and 10 cmH2O • Closed tracheal suction system attached with variable suction pressure (-20000 or -30000 Pa) during 5, 10, 15, and 20 seconds | • 25 and 50 cmH2O • Controlled by digital automated manometer | • Clear water (10 ml) | 4 tubes tested of each ETT type | PU cuffs leaked less (range 0–0.12 ml) than PVC cuffs (range 0.05–6.28 ml) at all Pcuff levels (p < 0.001) and at all negative suction pressures tested (p < 0.001) |
Kolobow, 2011 [27] | • 2 PU-cuffed ETTs (prototype tube with Lycra PU cuff, MICROCUFF, Kimberly-Clark, Kimberly-Clark Health Care, Roswell, Georgia, USA) • PVC-cuffed ETT (Hi-Lo, Mallinckrodt/Covidien, Boulder, Colorado, USA) ID all ETTs 8 mm | • Vertical acrylic tube trachea model, ID 20 mm • Cuffs not lubricated • No ventilatory simulation, no PEEP | • 20 cmH2O • Controlled by aneroid manometer | • Methylene blue-colored water (15 ml) • Leak time observation 24 h • Leakage expressed as milliliters per hour | 6 tubes tested of each ETT type | • No leakage in Lycra PU prototype ETT • The other PU cuff (MICROCUFF) allowed less leakage (1.2 ± 0.4 ml/h) than PVC cuff (1.2 ± 1.3 ml/h) (p < 0.001) |
Ouanes, 2011 [25] | • PU-cuffed ETTs (MICROCUFF, Kimberly-Clark, Zaventem, Belgium) • PVC-cuffed ETT (Rüschelit Super Safety Murphy, Rüsch GmbH, Kernen, Germany) ID ETTs 7.5 and 8 mm | • Vertical artificial Plexiglas trachea model, ID 18 mm • Cuffs not lubricated • Ventilatory settings 10 cmH2O PSV driven by active inspiration with trigger sensitivity at 2 L/minute and respiratory rate at 20 breaths/minute. Three effort intensities (occlusion pressure at 0.1 second): low = 2 cmH2O, moderate = 5 cmH2O, and high = 10 cmH2O • Experiments performed with PEEP 0 and 5 cmH2O | • 30 cmH2O • Controlled by manual manometer every 3 h | • Methylene blue (1 ml) diluted with 4 ml normal saline • Leak time observation 1 h • Leakage expressed as milliliters per hour | 3 tubes tested of each ETT type | At all inspiratory levels tested, significantly less leakage occurred with PU cuffs: mean 0.5 (SD 0.5) ml/h vs. 36.8 (SD 31.6) ml/h (p < 0.001) |
Zanella, 2011 [15] | • PU-cuffed ETTs (MICROCUFF, Kimberly-Clark, GA, USA) • 3 PVC-cuffed ETT (Mallinckrodt Hi-Lo, Mallinckrodt, NY, USA; Mallinckrodt High-Contour, Kimberly-Clark, Zaventem, Belgium; Portex Ivory, Smiths Medical, UK) ID all ETTs 8 mm | • Vertical PVC cylinder as trachea model, ID 20 mm • Cuffs not lubricated • Ventilatory settings: CPAP simulation with 4 levels of PEEP randomly applied (0, 5, 10, and 15 cmH2O) | • 30 cmH2O • Continuously controlled by water seal valve providing continuous positive pressure into pilot balloon | • Methylene blue-dyed water added above the cuff to make water column 10 cm • Leak time camera observation 24 h with picture taken every 60 seconds • Leakage expressed as water column above cuff (cm) • Leakage detected by blinded observer | 5 tubes tested of each ETT type, at PEEP 5–15 cmH2O 5 new ETTs tested at PEEP 0 | Leakage observed after 24 h: • PU cuff: - No leakage at PEEP levels 5, 10, and 15 cmH2O - Minor leak without PEEP (about 2 cm) • 3 types of PVC cuffs: -No leak at PEEP 15 cmH2O - Minor leak at PEEP 10 cmH2O (about 2 cm) - Major leak at PEEP 5 cmH2O (>8 cm) - Maximum leak without PEEP (10 cm) |
Li Bassi, 2013 [11] | • 8 HVLP ETTs with various cuff characteristics, among which were: PU-cuffed ETT (Kimvent MICROCUFF, Kimberly-Clark Health Care, Roswell, GA, USA) PVC-cuffed ETTs (Rüschelit Safety Clear Plus, Teleflex, Limerick, PA, USA; Hi-Lo, Covidien-Nellcore and Puritan Bennett, Boulder, CO, USA) • ID 7, 7.5, 8 mm | • Artificial trachea model (ID 18, 20, and 22 mm) oriented 30 degrees above horizontal • Cuffs not lubricated • No ventilatory simulation • Short-term fluid sealing capacity (1 h): 3 ETT IDs at 4 Pcuff levels • Long-term fluid sealing capacity (24 h) with 4 best-performing ETTs at 1 h; experiment performed with 7.5 mm ID ETTs and Pcuff 30 cmH2O • Measurement: multivariate analysis in which leakage rate was evaluated considering several other cuff characteristics: Pcuff, cuff OD, cuff length, PU cuff, taper-shaped cuff, ratio cuff OD/trachea model ID, ratio cuff OD/cuff length, cuff compliance, and trachea model ID | • 15, 20, 25, 30 cmH2O • Controlled by automated manometer | • Oropharyngeal secretion simulant (viscosity 3 cP at shear rate 75/second) • Leakage recorded as milliliters per hour • Leak time observation 1 h and 24 h | 3 tubes tested of each ETT type | PU cuffs leaked substantially less than PVC cuffs: • Short-term mean fluid leakage rates (1 h): - PU cuff (MICROCUFF): 0.09 ± 0.06 ml/h - PVC cuff (Rüschelit): 4.46 ± 3.47 ml/h - PVC cuff (Mallinckrodt Hi-Lo): 2.24 ± 1.93 ml/h • Long-term mean fluid leakage rates (24 h): - PU cuff (MICROCUFF): 0.69 ± 0.36 ml/h - PVC cuff (Mallinckrodt Hi-Lo): 114.74 ± 16.79 ml/h • In multivariate analysis (considering 8 types of ETTs with various cuff characteristics), internal Pcuff, cuff OD, and cuff length were independently associated with lower leakage rates; cuff material did not reach statistical significance in this model |
Lau, 2014 [23] | • PU-cuffed ETTs (Kimvent MICROCUFF, Kimberly-Clark Health Care, US) • PVC-cuffed ETT (Portex, Smiths Medical International Ltd., UK) ID all ETTs 8 mm | • Silicone cylinder trachea model (ID 20 mm) oriented 35 degrees above horizontal • Cuffs not lubricated • Ventilatory settings: 5 simulated mechanical ventilation scenarios, including different PEEP levels and disconnection with and without spontaneous breathing effort. Each scenario was tested under 3 Pcuff levels and then repeated with application of continuous suction force (−200 cmH2O for 3 minutes) | • 10, 20, 30 cmH2O • Maintained by automated device | • Clear water (20 ml) • Leakage observation time 20 minutes. • Leakage was video-recorded and expressed as cumulative amount of leakage (ml) | 2 ETTs of each type, and each ETT tested 4 times (8 measurements for each ETT per scenario and Pcuff) | PU cuffs consistently demonstrated best protection against fluid leakage; clinical situations associated with greater leakage were mechanical ventilation without PEEP, circuit disconnection with spontaneous breathing, application of suction, and low Pcuff (10 cmH2O) |
In vivo study | ||||||
Li Bassi, 2015 [26] | • PU-cuffed ETTs (KimVent MICROCUFF, Halyard Health, USA) • PVC-cuffed ETT (Rüschelit Safety Clear Plus, Teleflex Incorporated, Limerick, PA, USA) ID ETTs not reported | • Large White-Landrace pigs (37.3 ± 3.6 kg) randomized to be intubated with either of the test ETTs • 5 pigs in PU group • 4 pigs in PVC group • Intubated, ventilated, and anesthetized for 76 h • After 52 and 73 h, pigs were placed in prone, bed oriented 30 degrees above horizontal, and PEEP reduced to 0 | • 28 cmH2O • Maintained by automated device | • Methylene blue (2 ml) and phosphate-buffered solution (3 ml) with 1.5 μl of 2.0-μm Invitrogen fluorescent microspheres (Life Technologies, Carlsbad, CA, USA) • 1 h from instillation, leakage estimated by presence of methylene blue and quantification of microspheres in tracheal secretions quantified by calculating percentage of recovered microspheres per gram of tracheal secretions per total amount of instilled microspheres | 1 ETT per animal | • Methylene blue was never found in tracheal secretions • Percentage of aspirated microspheres was not significantly lower with PU cuffs (0.06 ± 0.05 %) than with PVC cuffs (0.12 ± 0.06 %) |
Author, year | Materials tested | Study design | Pcuff
| Outcomes | Main results |
---|---|---|---|---|---|
Lucangelo, 2008 [14] | • PU-cuffed ETT, cylindrical shape (Mallinckrodt SealGuard, Mallinckrodt Medical, Cornamady, Anthlone County, Ireland) • PVC-cuffed ETT, spindle-like shape (Mallinckrodt Hi-Lo, Mallinckrodt Medical, Cornamady, Anthlone County, Ireland) | • RCT • 2 groups of 20 ICU patients requiring immediate orotracheal intubation and mechanical ventilation because of deterioration of consciousness (GCS score ≤8) • Ventilatory settings: VC ventilation with VT 8–9 ml/kg and respiratory rate to maintain normocapnia, and PEEP (5 cmH2O) • 5 h postintubation, PEEP was removed • Oral and tracheal secretions were not aspirated during experiment | • 30 cmH2O • Controlled with aneroid manometer | • Evans blue (1 ml) diluted in normal saline (1 ml) • Bronchoscopic evaluation to detect blue dye in trachea at 1 h and 5 h postintubation (with PEEP) and hourly thereafter until 12 h postintubation (without PEEP) • As soon as blue spot was seen on trachea caudal to ETT tip, experiment was finished | • 5 h postintubation, leakage observed in 2 patients in PVC group • At 6th hour (1 h after PEEP removal), leakage observed in all patients in PVC group • In the PU group, first leakage occurred after 8 h; at end of experiment (12th hour), fluid leakage absent in 3 patients • Difference between the 2 groups (log-rank test on Kaplan-Meier survival curves) was statistically significant (p < 0.001) |
Poelaert, 2008 [30] | • PU-cuffed ETT, cylindrical shape (SealGuard, Covidien, Mansfield, Mass, USA) • PVC-cuffed ETT, cylindrical shape (standard Mallinckrodt, Mallinckrodt Inc. Hazelwood, Mo, USA) • Female patients: ID 8 mm • Male patients: ID 9 mm | • RCT, single-blind • 2 groups of 67 patients scheduled for cardiac surgery • Intraoperative antibiotic prophylaxis with cefazolin 2 g 3 times daily for 24 h | • 20–26 cmH2O • Controlled immediately after intubation, at closure of sternum, on arrival at ICU, and every 4 h during postoperative course | • Early postoperative pneumonia (until 7 days postoperatively) • Nosocomial pneumonia was defined as all of the following: - New/evolving infiltrate on chest x-ray - Temperature > 38.2 °C - Leukocytosis (>12000 cells/mm3) - Presence of purulent sputum/endotracheal aspirate - Increase in C-reactive protein for 2 consecutive postoperative days - Deterioration in PaO2/FiO2 ratio ≥20 % • Diagnosis: assessor blinded | • Rate of postoperative pneumonia in PU group significantly lower than PVC group (23 % vs. 42 %; p = 0.026) • In multivariate regression analysis, use of PU-cuffed ETTs appeared to be protective for early postoperative pneumonia (OR 0.31, 95 % CI 0.13–0.77) |
Nseir, 2010 [40] | • PU-cuffed ETT, cylindrical shape (MICROCUFF, Kimberly-Clark, Zaventem, Belgium) • PVC-cuffed ETT, cylindrical shape (Mallinckrodt Hi-Lo Lanz, Mallinckrodt Medical, Athlone, Ireland) | • Prospective, observational trial in ICU patients • PVC group (patients included in first 6 months of study, n = 26); PVC group (patients included in second period of 6 months, n = 22) • Patients observed during 24 h with continuous monitoring of Pcuff
• After 24 h, tracheal suctioning to obtain aspirate sample for pepsin measurement • Pepsin levels considered positive at 200 ng/ml | • 25 cmH2O • Manually adjusted every 8 h | • Pepsin in tracheal secretions (ng/ml) used as proxy for microaspiration of gastric contents • Recorded 24 h postintubation | • No difference in Pcuff variation observed between groups • Pepsin levels lower among patients with PU-cuffed ETTs (217 ± 126 ng/ml) than in PVC group (408 ± 282 ng/ml) • Pepsin levels >200 ng/ml more common in PVC group (69 % vs. 27 %; p = 0.008) • Pepsin levels >300 ng/ml more common in PVC group (61 % vs. 22 %; p = 0.009) |
Miller, 2011 [32] | • PU-cuffed ETT, cylindrical shape (MICROCUFF, Kimberly-Clark Corporation, Roswell, GA, USA) • PVC-cuffed ETT, cylindrical shape (conventional type) | • Before-after study with interrupted time-series analysis • 1 hospital, 5 ICUs • Retrospective comparison of VAP rates in respective periods • 1 year of observation with PVC-cuffed tubes before intervention • 1 year of observation with PU-cuffed ETTs • 3 months postintervention observation (return to conventional PVC-cuffed ETTs) | Not reported | • VAP rates expressed per 1000 ventilation days • VAP diagnosed on basis of clinical or microbiologic criteria, based on CDC’s National Healthcare Safety Network standard definition [29] | • Baseline year of observation (PVC-cuffed ETT): 37 VAP episodes (5.3/1000 ventilation days) • Intervention year (PU-cuffed ETT): 21 VAP episodes (2.8/1000 ventilation days) (p = 0.0138) • After return to PVC-cuffed ETTs, 6 episodes in 3 months (3.5/1000 ventilation days) • Incidence risk ratio of VAP during intervention year 0.57 (95 % CI 0.34–0.96) |
Philippart, 2015 [31] | • PU-cuffed ETT, cylindrical shape (MICROCUFF, Kimberly-Clark, Irving, Tx, USA) • PVC-cuffed ETT, cylindrical shape (Hi-Lo, Covidien, Dublin, Ireland) • PU-cuffed ETT, conical shape (SealGuard, Covidien, Dublin, Ireland) • PVC-cuffed ETT, conical shape (TaperGuard, Covidien, Dublin, Ireland) • ID 7.5 or 8 mm | • Multicenter RCT, 4 study arms • PU cylindrical group (n = 123) • PVC cylindrical group (n = 129) • PU conical group (n = 153) • PVC conical group (n = 129) At study inclusion, no important differences between groups were observed | • 25–30 cmH2O • Manually controlled with manometer every 6 h • Airway management standardized across study sites | • Primary endpoint: bacterial colonization of the trachea (103 CFU/ml) at days 1, 2, 3, 7 • Secondary endpoint: cumulative VAP rate during ICU stay, defined on basis of clinical, biological and radiological patterns [41]; bacterial cultures sampled in all patients suspected of having VAP and confirmed if quantitative culture was at least 104 CFU/ml | • No differences in tracheal colonization (at >103, >104, >105, or >106 CFU/ml) were observed 48 h postintubation (p > 0.05, p value indicates difference across 4 groups) • VAP rate between PU cylindrical and PVC cylindrical group not different (resp. 17.1 % vs. 10.8 %; p = 0.202) • VAP rate between PU conical and PVC conical group not different (respectively 16.3 % vs. 13.2 %; p = 0.505) • No difference in VAP rate observed when both PU groups and both PVC groups were pooled (respectively 16.6 % vs. 12.0 %; p = 0.140) |