The effect of saline instillation during physiotherapy (SIP) in the intensive care unit - a randomized crossover trial

Insertion of an artificial airway for respiratory failure, either endotracheal, nasotracheal or tracheostomy, inhibits normal mucociliary clearance, thus increasing the risk of secretion retention and pneumonia. Suctioning of the artifical airway is one of the most common procedures in the intensive care unit and high dependency wards: the aim is to remove respiratory tract secretions, thus maintaining airway patency, and prevent complications of secretion retention. Normal saline instillation is defined as delivery of 2 to 10 cc of normal saline solution (0.9%) into an artificial airway prior to suctioning. This technique is utilised by many health practitioners and is believed to increase sputum yield by diluting and loosening secretions, stimulating a cough and lubricating the suction catheter. However, there are conflicting views about the safety and efficacy of this procedure. To date studies have investigated saline instillation as a stand alone technique and not as part of a respiratory physiotherapy regimen. The aim of this trial is to examine the effects of normal saline instillation on sputum clearance, haemodynamic parameters, oxygenation and respiratory mechanics during physiotherapy in patients with an artificial airway. Design Prospective, single blinded, randomised, cross-over design where patients act as their own controls. Patients will be randomised using a computer generated sequence. Those allocated to group A will have saline instillation prior to suction during physiotherapy on day one, day two no saline will be used. The reverse will happen for those patients allocated to group B. Investigator collecting outcome measures will be blinded to group allocation. Participants Adults >18 years, expected to be mechanically ventilated for >48 hours. Outcome measures The primary outcome measure is sputum weight. Sputum will be collected during physiotherapy.Secondary outcome measures include airway resistance, oxygenation, blood pressure and heart rate which will be calculated at various times pre and post procedure. Significance This study would add to the body of knowledge regarding the efficacy and safety of saline instillation during physiotherapy in the intensive care unit.