BACKGROUND: The investigators developed a fiber-optic-guided endotracheal suction catheter (visual sputum suctioning system or VSSS), which the investigators previously tested in vitro and animals. It integrates a 0.9-mm micro-imaging fiber into a 3.7-mm double-lumen catheter.

PURPOSE: The purpose of this study was to investigate the safety and efficacy of sputum suctioning system in mechanical ventilated patients in respiratory intensive care unit (RICU). The investigators compare the weight of secretions collected, vital signs, and tracheal wall injury between two groups of patients randomized to have VSSS combined with closed system suction (CSC) suction and patients having CSC suction alone.

HYPOTHESIS: The investigators theorized that the VSSS collected more sputum and caused less change of vital signs than conventional CSC.

Study design: This is a randomized controlled trial study, including patients ventilated in one respiratory intensive care unit (RICU). Two suction systems (The novel VSSS and conventional CSS alone) will be compared at time point before (baseline), immediately after, 3 min after, and 5 min after suctioning.

Background: Sputum suctioning is a routine clinical procedure that is crucial for keeping the airway open, to reduce the incidence of respiratory-tract infections. In most circumstances, a conventional catheter with a single-lumen channel is used for sputum suctioning. However, this procedure Involves blind manipulation of the catheter on the part of the clinician and thus depends largely on the clinician's skills and experience. Therefore, complications occur in some patients, especially on the changes of the parameters of the heart-lung system. In addition, because clinicians cannot directly target sputum in the trachea, the efficiency of the procedure may be reduced.

Recently, a visual sputum suctioning system (VSSS) was developed in our research group. It integrates a 0.9-mm micro-imaging fiber into a 3.7-mm double-lumen catheter.

In vitro tests investigators found that the ability to visualize the airway allows targeting of sputum, which compensates for the smaller lumen and makes the suctioning procedure more efficient overall. In addition, in animal tests investigators found that the VSSS collected more sputum and caused less tracheal mucosa damage than conventional suctioning.

Purpose: The present study investigated the safety and efficacy of sputum suctioning system with this double-lumen catheter in mechanical ventilated patients in respiratory intensive care unit (RICU). The purpose of this study was to compare the weight of secretions collected, vital signs, and tracheal wall injury between two groups of patients randomized to have VSSS combined with closed system suction (CSC) suction and patients having CSC suction alone. investigators theorized that the VSSS collected more sputum and caused less change of vital signs than conventional CSC.

Registry procedure: All requested information will be recorded on case report forms and explanation will be reported for any missing data. False data will be clearly corrected, and signed by investigator or authorized person.

Monitoring will be realized by the co-investigator in association with the clinical research associate.

Sample size assessment: Number of subjects: 40 patients. Three months should be necessary to include these patients.

Statistical analysis: Investigators determined that 20 patients per group would provide a power of 95%, with a α level of 5%.

Results will be expressed as means ± Standard Deviation. SPSS 10.0 (Chicago, Illinois, USA) for the statistical calculation was used. P values < 0.05 were considered statistically significant. Investigators used the nonparametric t test for normally distributed data, and the nonparametric Wilcoxon-Mann-Whitney rank test for other data.Investigators used repeated-measures analysis of variance at four time points (before suctioning, immediately after suctioning, 3 min after suctioning, and 5 min after suctioning) to analyze changes and differences in PaO2, heart rate, and mean arterial pressure.

Inclusion Criteria:

• Patients admitted to RICU
• 18 years old or more
• Ventilated more than 24 hours mechanical ventilation
• Patients with stability (MAP>70 mmHg, HR<130 b/min)
• Signed informed consent

Exclusion Criteria:

• Current or past participation in another intervention trial conflicting with the present study patients with stupor and coma
• Any clinical events or practitioner interventions within 15 min prior to study enrollment (eg, a change in ventilator settings, hemodynamic instability [DBP >100 mmHg; ↑or 20mmHg in PaO2; ↑20 b/min in HR]; sever hypoxemia [SpO2<85%, PaO2<50mmHg])
• Had heart or lung or heart transplantation.
• Had massive hemoptysis.
• Pregnant women