Open Suction Research Articles

Ventilator-associated pneumonia with a closed versus an open endotracheal suction system

Ventilator-associated pneumonia with a closed versus an open endotracheal suction system

Hypoxaemia during tracheal suctioning; comparison of closed versus open techniques at varying PEEP

Suctioning of artificial airways is a necessary procedure but is not without risk. Hypoxaemia is a recognised complication. Several small studies have suggested that closed suction catheters offer benefits over open suction because disconnection from the ventilator circuit is not required [1], thereby maintaining ventilation, FIO2 and PEEP. Other studies have sought to prove the maintenance of lung volume and cardiovascular stability with closed suction [2]. There is little evidence that closed suction systems offer clinical advantage over open suction in terms of arterial oxygenation. No published study had compared changes in PaO2/FIO2 post suction. We performed a study in critically ill adults to identify any differences in PaO2/FIO2 between closed and open suction for a given PEEP.

Chest X-ray quiz.

Endotracheal suctioning (ETS) is one of the most common procedures performed in the paediatric intensive care. The two methods of endotracheal suctioning used are known as open and closed suction, but neither method has been shown to be the superior suction method in the Paediatric Intensive Care Unit (PICU).The primary purpose was to compare open and closed suction methods from a physiological, safety and staff resource perspective.All paediatric intensive care patients with an endotracheal tube were included. Between June and September 2011 alternative months were nominated as open or closed suction months. Data were prospectively collected including suction events, staff involved, time taken, use of saline, and change from pre-suction baseline in heart rate (HR), mean arterial pressure (MAP) and oxygen saturation (SpO2). Blocked or dislodged ETTs were recorded as adverse events.Closed suction was performed more often per day (7.2 vs 6.0, p < 0.01), used significantly less nursing time (23 vs 38 min, p < 0.01) and had equivalent rates of adverse events compared to open suction (5 vs 3, p < 0.23). Saline lavage usage was significantly higher in the open suction group (18% vs 40%). Open suction demonstrated a greater reduction in SpO2 and nearly three times the incidence of increases in HR and MAP compared to closed suction. Reductions in MAP or HR were comparable across the two methods.In conclusion, CS could be performed with less staffing time and number of nurses, less physiological disturbances to our patients and no significant increases in adverse events.

Lung volume and oxygenation changes with a closed suction system (CSS) in patients undergoing volume controlled ventilation (VCV)

We wished to measure changes in lung volume (Δ LV), airway pressures, and oxygenation during tracheal suctioning performed with a CSS and with an open suction system (OSS). We enrolled 7 adult patients, sedated and paralyzed, VCV ventilated by a SERVO 900C ventilator (Siemens, Sweden) with PEEP ≥ 5 cmH2O and FiO2 ≥ 0.4. Keeping all remaining ventilarory settings unchanged, we set trigger sensitivity at -2 cmH2O, inspiratory time at 25%, inspiratory pause at 10%. We performed four suctioning manouvers at 20 min intervals using alternatively a CSS and an OSS. With both systems, we used 12 F size catheters. We performed no pre-oxygenation manouvers. Suction was applied for 20 s at a pressure of 100 cmH2O. We continuously recorded signals of respiratory inductance pletismography (RIP. Respitrace Plus. NIMS, FL), arterial oxygen saturation (O2Sat) by pulse oxymetry, and airway pressures. We obtained Δ LV as the change in the RIP signal measured during VCV and during suction. We measured Respiratory Rate (RR), peak inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), and mean airway pressure(MAP) during VCV and during suction with the CSS.

The Design of a Twin-screw Compressor Based on a New Rotor Profile

SUMMARY This paper describes the design of a high-efficiency twin-screw compressor with new rotor profiles. A well-proven mathematical model of the compression process within positive displacement machines was used to determine the optimum rotor size and speed, the volume ratio, and the oil injection position and jet diameter. In addition, modern design concepts such as an open suction port and early exposure of the discharge port were included, together with improved bearing and seal specification, to maximize the compressor efficiency. The prototype was tested and compared with the best compressors currently on the market. Its minimum measured specific power input at a delivery pressure of 8 bar (abs) was 5.6 kW m-3 min-1. This is less than the published value for any other equivalent compressor currently manufactured. Both the predicted advantages of the new rotor profile and the superiority of the design procedure were thereby confirmed.