Interrupting gel layer between Double cuffs prevents fluid leakage past tracheal tube cuffs

An endotracheal tube providing "pressurized sealing" prevents fluid leakage in mechanically ventilated critically ill patients: a pilot study

Microaspiration of bacteriologically contaminated oropharyngeal secretions alongside the cuff of an endotracheal tube (ETT) is a key mechanism for development of ventilator-associated pneumonia. We have constructed a prototype double-cuffed ETT equipped with a supplemental port in-between the cuffs through which continuous positive airway pressure (CPAP) is delivered. Pressure in the intercuff space propels secretions upwards and produces 100% tracheal sealing in an in vitro model. We conducted a 24 h study to investigate the sealing effect of this ETT in 12 critically ill mechanically ventilated patients. Methylene blue, instilled through a bronchoscope on top of the proximal cuff, was used as leakage tracer. Fiberoptic visualisation of the trachea was performed 1 h and 24 h thereafter. Leakage was confirmed if blue dye was detected on the tracheal mucosa beyond the tip of the ETT. In no patient, dye passed by the cuffs during the study period. Presence of the ETT did not interfere with ventilator settings, patient mobilization, physiotherapy, and technical acts. Overall, pressures in the intercuff space remained between 10 and 15 cmH₂O. Excessive pressure swings were swiftly corrected by the CPAP system. A double-cuffed ETT, offering “pressurized sealing” of the trachea, safely and effectively prevented leakage during 24 h mechanical ventilation.

Devising negative pressure within intercuff space reduces microaspiration

Background

Microaspiration past the tracheal tube cuffs causes ventilator-associated pneumonia. The objective of the current study was to evaluate whether creating negative pressure between the tracheal double cuffs could block the fluid passage past the tracheal tube cuffs.

Methods

A new negative pressure system was devised between the double cuffs through a suction hole in the intercuff space. Blue-dyed water was instilled above the cuff at negative suction pressures of − 54, − 68, − 82, − 95, − 109, − 122, and − 136 cmH₂O, and the volume leaked was measured in an underlying water trap after 10 min. Leakage tests were also performed during positive pressure ventilation, and using higher-viscosity materials. The actual negative pressures delivered at the hole of double cuffs were obtained by placing microcatheter tip between the intercuff space and the artificial trachea.

Results

No leakage occurred past the double cuff at − 136 cmH₂O suction pressure at all tracheal tube cuff pressures. The volume leaked decreased significantly as suction pressure increased. When connected to a mechanical ventilator, no leakage was found at − 54 cmH₂suction pressure. Volume of the higher-viscosity materials (dynamic viscosity of 63–108 cP <cP> and 370–430 cP) leaked was small compared to that of normal saline (0.9–1.1 cP). The pressures measured in the intercuff space corresponded to 3.8–5.9% of those applied.

Conclusions

A new prototype double cuff with negative pressure in the intercuff space completely prevented water leakage. The negative pressure transmitted to the tracheal inner wall was a small percentage of that applied.

Role of Swallowing Function of Tracheotomised Patients in Major Head and Neck Cancer Surgery

INTRODUCTION

Tracheotomy is a frequent procedure in extended head and neck cancer surgery and known to be a risk factor for prolonged hospitalization. The authors hypothesized that the clinical course and delayed decannulation of patients are not only influenced by airway narrowing, but also by a compromised postoperative swallowing function.

MATERIAL AND METHODS

The investigators implemented a retrospective cohort study. The sample was composed of a tertiary care center patients who underwent major head and neck cancer surgery, each receiving a tracheostomy. Data collected include general clinical data as well as endoscopical evaluation of swallowing function and aspiration rate. Descriptive and bivariate statistics were computed and the P value was set at.05.

RESULTS

The sample was composed of 96 patients with an average age of 64.2 and sex ratio of 1.4:1 (m:f). There was a strong statistically significant relation between swallowing function and timing of decannulation (P < 0.001) and duration of hospitalization (P < 0.001). Age (P = 0.55), sex (P = 0.54), tumor size (P = 0.12), general diseases (P = 0.24), distant metastases (P = 0.15), or extent of neck dissection (P = 0.15) were not significantly associated to swallowing function. Permanent cannulation was significantly correlated to a primary cancer of the soft palate or base of the tonge (P < 0.001).

CONCLUSION

The results of this study confirm the importance of the evaluation of swallowing function before the removal of the tracheotomy cannula in head and neck cancer patients.

Orotracheal tube as a risk factor for lower respiratory tract infection: preliminary data from a randomised trial

PURPOSE

The aim of the study was to investigate whether polyurethane (PU) endotracheal tubes, continuous measurements of cuff pressure and aspiration of the subglottic space as a bundle of parameters could reduce patients' risk for developing ventilator associated pneumonia (VAP).

METHODS

Two groups of patients that differed only in terms of endotracheal tubes and intubation intervention were compared. Group A was ventilated using PU tubes a with conical cuff; they also had continuous cuff pressure measurement and continuous subglottic aspiration. Group B was ventilated using PVC tubes with a cylindrical cuff; the patients underwent intermittent cuff pressure measurement and intermittent subglottic aspiration.

RESULTS

Seven patients in group A (13.2%) and 18 in group B (36.0%) out of 103 were diagnosed with VAP. VAP patients were in general older, stayed longer in the ICU and were ventilated significantly longer compared with the patients with no VAP. Eight more patients in group B died compared with group A. Moreover, subjects in group A survived longer. Patient age, hours on mechanical ventilation, and days on an ICU were all positively associated with the occurrence of VAP.

CONCLUSIONS

Prevention parameters in ventilation (PU cuff, conical cuff, continuous subglottic drainage and continuous cuff pressure measurement) could prevent the incidence of VAP in ICU patients.