In-line Suction Catheters May Impede Aerosol Delivery to Patients Receiving Mechanical Ventilation

Abstract

To the Editor:A recent article suggests that closedin-line suction catheters are used frequently in patientsreceiving intubation and /or mechanical ventilation.1Paul-Allen J Ostrow CL Survey of nursing practices with closed-system suctioning.Am J Crit Care. 2000; 9: 9-17PubMed Google Scholar Wehave been concerned that some of these devices trap aerosolizedmedications, preventing them from reaching the airways of our patients. Some in-line suction catheters include a potentiallyturbulence-creating 90° adapter that becomes moist during use. Theoretically, these attributes could impede the delivery oftherapeutic aerosols to patients’ airways.2Dhand R Tobin MJ Inhaled bronchodilator therapy in mechanically ventilated patients.Am J Respir Crit Care Med. 1997; 156: 3-10Crossref PubMed Scopus (165) Google ScholarWe informally examined the effectiveness of a nebulized bronchodilatorwhen administered with an in-line suction catheter left in place, vshaving it removed from the patient-ventilator circuit. The Steri-Cath(SIMS Portex; Keene, NH) is a closed-suction system used for allpatients receiving intubation and /or mechanical ventilation in ourhospital. This system consists of a 57-cm, 14F (4.7-mm outer diameter)catheter wrapped in plastic foil, connected in a straight line with theendotracheal tube (ETT) via a three-way connector. The inner diameterof the orifice connecting to the ETT is 15 mm. The ventilator wye-piececonnects at 90° to the ETT-suction catheter axis via the thirdaperture (inner diameter, 12 mm) of the three-way connector.Two sequential nebulized albuterol treatments of 2.5 mg in 3 m, L weregiven to three patients at intervals of 20 to 30 min, one with thesuction catheter in the circuit, and one with the suction catheter and three-way connector out (wye connected directly to the ETT). Airwaypressures (peak and plateau) were measured with constant inspiratoryflow rates of 60 L/min, before and 20 min following treatments. Thesuction catheter was in-line during measurements, but the catheter waswithdrawn into its plastic sheath (outside the three-way connector). Noendotracheal suctioning occurred between sets oftreatments/measurements. Airway resistance was computed as thedifference between peak and plateau airway pressure. Fourrounds of treatments/measurements were performed in three patients whowere receiving nebulized treatments in our ICU; three of four caseswere treated first with the catheter in the system during nebulization, followed by a second treatment with the catheter and connector removedfrom the system. One patient received two rounds of measurements (bothwith the catheter in the system for the first albuterol treatment).With the catheter in the system during treatments, airway resistancewas 19.0 ± 1.5 cm H2O/L/s before and 18.1 ± 1.9 cm, H2O/L/s (p = 0.24) after 2.5 mg of nebulized albuterol. Airway resistance decreased significantly from 19.4 ± 2.8 to14.4 ± 2.6 cm H2O/L/s (p = 0.01) after 2.5 mg ofalbuterol administered with the suction catheter out of (removed from)the system.Because treatments were not randomized and because there were onlyeight observations, we drew no conclusions from these findings. Nonetheless, these data suggest that the closed in-linesuction catheter used in our hospital prevented aerosolized medicationfrom reaching the airways of these intubated patients receivingmechanical ventilation. We suspect that the 90°, three-way connectorbetween the ETT and the wye trapped aerosolized particles. Importantly, aerosolized bronchodilators were effective when administered withanother brand of in-line closed suction device3Dhand R Jubran A Tobin MJ Bronchodilator delivery by metered-dose inhaler in ventilator-supported patients.Am J Respir Crit Care Med. 1995; 151: 1827-1833Crossref PubMed Scopus (80) Google Scholar ( Rajiv Dhand, MD; personal communication; March 2000). Either bench trials orprospective, randomized clinical studies are required to answer thisquestion for each device on the market.Physicians and respiratory therapists should be aware that some brandsof closed in-line suction catheters, used by 93% of nurses caring foradult patients,1Paul-Allen J Ostrow CL Survey of nursing practices with closed-system suctioning.Am J Crit Care. 2000; 9: 9-17PubMed Google Scholar may impede delivery of therapeuticaerosols. When aerosolized bronchodilator treatments fail to reduceairway resistance, and elevated resistance increases risk to thepatient (eg, significant dynamic hyperinflation and /orweaning failure), clinicians should consider removing the suctioncatheter during treatment to determine if removal leads to the desiredeffect (bronchodilation). To reduce the risk of infection tohealth-care workers and patients, closed-suction systems are now usedin the majority of critically ill patients receiving mechanicalventilation. Not infrequently, new devices are introduced to theclinical are na with the best of intentions, but without thoroughconsideration of potential negative effects. We should have learnedfrom the available data that, in aerosol delivery, “the devil is inthe details.” Seemingly trivial changes in the patient-ventilatorcircuit can significantly reduce the effectiveness of thesetreatments.4Newhouse MT Fuller HD Rose is a rose is a rose? Aerosol therapy in ventilated patients: nebulizers versus metered dose inhalers; a continuing controversy.Am Rev Respir Dis. 1993; 148: 1444-1446Crossref PubMed Google Scholar To the Editor: A recent article suggests that closedin-line suction catheters are used frequently in patientsreceiving intubation and /or mechanical ventilation.1Paul-Allen J Ostrow CL Survey of nursing practices with closed-system suctioning.Am J Crit Care. 2000; 9: 9-17PubMed Google Scholar Wehave been concerned that some of these devices trap aerosolizedmedications, preventing them from reaching the airways of our patients. Some in-line suction catheters include a potentiallyturbulence-creating 90° adapter that becomes moist during use. Theoretically, these attributes could impede the delivery oftherapeutic aerosols to patients’ airways.2Dhand R Tobin MJ Inhaled bronchodilator therapy in mechanically ventilated patients.Am J Respir Crit Care Med. 1997; 156: 3-10Crossref PubMed Scopus (165) Google Scholar We informally examined the effectiveness of a nebulized bronchodilatorwhen administered with an in-line suction catheter left in place, vshaving it removed from the patient-ventilator circuit. The Steri-Cath(SIMS Portex; Keene, NH) is a closed-suction system used for allpatients receiving intubation and /or mechanical ventilation in ourhospital. This system consists of a 57-cm, 14F (4.7-mm outer diameter)catheter wrapped in plastic foil, connected in a straight line with theendotracheal tube (ETT) via a three-way connector. The inner diameterof the orifice connecting to the ETT is 15 mm. The ventilator wye-piececonnects at 90° to the ETT-suction catheter axis via the thirdaperture (inner diameter, 12 mm) of the three-way connector. Two sequential nebulized albuterol treatments of 2.5 mg in 3 m, L weregiven to three patients at intervals of 20 to 30 min, one with thesuction catheter in the circuit, and one with the suction catheter and three-way connector out (wye connected directly to the ETT). Airwaypressures (peak and plateau) were measured with constant inspiratoryflow rates of 60 L/min, before and 20 min following treatments. Thesuction catheter was in-line during measurements, but the catheter waswithdrawn into its plastic sheath (outside the three-way connector). Noendotracheal suctioning occurred between sets oftreatments/measurements. Airway resistance was computed as thedifference between peak and plateau airway pressure. Fourrounds of treatments/measurements were performed in three patients whowere receiving nebulized treatments in our ICU; three of four caseswere treated first with the catheter in the system during nebulization, followed by a second treatment with the catheter and connector removedfrom the system. One patient received two rounds of measurements (bothwith the catheter in the system for the first albuterol treatment).With the catheter in the system during treatments, airway resistancewas 19.0 ± 1.5 cm H2O/L/s before and 18.1 ± 1.9 cm, H2O/L/s (p = 0.24) after 2.5 mg of nebulized albuterol. Airway resistance decreased significantly from 19.4 ± 2.8 to14.4 ± 2.6 cm H2O/L/s (p = 0.01) after 2.5 mg ofalbuterol administered with the suction catheter out of (removed from)the system. Because treatments were not randomized and because there were onlyeight observations, we drew no conclusions from these findings. Nonetheless, these data suggest that the closed in-linesuction catheter used in our hospital prevented aerosolized medicationfrom reaching the airways of these intubated patients receivingmechanical ventilation. We suspect that the 90°, three-way connectorbetween the ETT and the wye trapped aerosolized particles. Importantly, aerosolized bronchodilators were effective when administered withanother brand of in-line closed suction device3Dhand R Jubran A Tobin MJ Bronchodilator delivery by metered-dose inhaler in ventilator-supported patients.Am J Respir Crit Care Med. 1995; 151: 1827-1833Crossref PubMed Scopus (80) Google Scholar ( Rajiv Dhand, MD; personal communication; March 2000). Either bench trials orprospective, randomized clinical studies are required to answer thisquestion for each device on the market. Physicians and respiratory therapists should be aware that some brandsof closed in-line suction catheters, used by 93% of nurses caring foradult patients,1Paul-Allen J Ostrow CL Survey of nursing practices with closed-system suctioning.Am J Crit Care. 2000; 9: 9-17PubMed Google Scholar may impede delivery of therapeuticaerosols. When aerosolized bronchodilator treatments fail to reduceairway resistance, and elevated resistance increases risk to thepatient (eg, significant dynamic hyperinflation and /orweaning failure), clinicians should consider removing the suctioncatheter during treatment to determine if removal leads to the desiredeffect (bronchodilation). To reduce the risk of infection tohealth-care workers and patients, closed-suction systems are now usedin the majority of critically ill patients receiving mechanicalventilation. Not infrequently, new devices are introduced to theclinical are na with the best of intentions, but without thoroughconsideration of potential negative effects. We should have learnedfrom the available data that, in aerosol delivery, “the devil is inthe details.” Seemingly trivial changes in the patient-ventilatorcircuit can significantly reduce the effectiveness of thesetreatments.4Newhouse MT Fuller HD Rose is a rose is a rose? Aerosol therapy in ventilated patients: nebulizers versus metered dose inhalers; a continuing controversy.Am Rev Respir Dis. 1993; 148: 1444-1446Crossref PubMed Google Scholar