Reducing Ventilator Alarms Through Decreased Rainout in Ventilator Circuits: A Bench Study

Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity settings such as intensive care, surgery, and emergency departments. Alarms are triggered by various devices such as anesthesia machines, ventilators, patient monitors or humidifiers. Heated humidifiers (HH) used with mechanical ventilators, while necessary to prevent other complications associated with mechanical ventilator, may cause condensation in the ventilator circuit, prompting occlusion alarms indicating a risk for the patient. Technological advances in heated humidifier (HH) circuits may reduce rainout and therefore occlusion alarms. Methods:Bench experiments measured alarms and rainout of two commercially available humidifiers (AirLife DuoTherm™ and Fisher & Paykel MR850) and four different pediatric and adult patient’s breathing. The tests examined condensation accumulation after 24 hours of low-, nominal-, or high-flow rates of gas at low-, nominal-, and high-ambient temperature settings. Dual-limb designs of adult- and neonate-sized circuits underwent evaluation. Data on alarms was collected for each system.Results:Low temperature and occlusion alarms were statistically significantly lower in DuoTherm vs. MR850 HH circuits (6 vs. 68 alarms, respectively; p<nn). DuoTherm products accumulated significantly less rainout for all three circuit sizes at all ambient temperatures. In general, the set flow rate did not dramatically affect the amount of rainout for adult and infant circuits, but low versus high ambient temperatures yielded increased rainout for all circuit types (p < 0.02). Conclusions:The DuoTherm HH device and patient circuits developed significantly less alarms due to rainout and low temperatures compared to those from MR850 under all the conditions tested. Such reduction in patient alarms should help reduce alarm fatigue among healthcare workers in critical care settings.

Reducing Ventilator Alarms Through Decreased Rainout in Ventilator Circuits: A Bench Study

Background:Alarm fatigue is a significant problem in healthcare, particularly in high acuity settings such as intensive care, surgery, and emergency departments. Alarms are triggered by various devices such as anesthesia machines, ventilators, patient monitors or humidifiers. Heated humidifiers (HH) used with mechanical ventilators, while necessary to prevent other complications associated with mechanical ventilator, may cause condensation in the ventilator circuit, prompting occlusion alarms indicating a risk for the patient. Technological advances in heated humidifier (HH) circuits may reduce rainout and therefore occlusion alarms. Methods:Bench experiments measured alarms and rainout of two commercially available humidifiers (AirLife DuoTherm™ and Fisher & Paykel MR850) and four different pediatric and adult patient’s breathing. The tests examined condensation accumulation after 24 hours of low-, nominal-, or high-flow rates of gas at low-, nominal-, and high-ambient temperature settings. Dual-limb designs of adult- and neonate-sized circuits underwent evaluation. Data on alarms was collected for each system.Results:Low temperature and occlusion alarms were statistically significantly lower in DuoTherm vs. MR850 HH circuits (6 vs. 68 alarms, respectively; p<nn). DuoTherm products accumulated significantly less rainout for all three circuit sizes at all ambient temperatures. In general, the set flow rate did not dramatically affect the amount of rainout for adult and infant circuits, but low versus high ambient temperatures yielded increased rainout for all circuit types (p < 0.02). Conclusions:The DuoTherm HH device and patient circuits developed significantly less alarms due to rainout and low temperatures compared to those from MR850 under all the conditions tested. Such reduction in patient alarms should help reduce alarm fatigue among healthcare workers in critical care settings.

Quantifying Delivered Dose with Jet and Mesh Nebulizers during Spontaneous Breathing, Noninvasive Ventilation, and Mechanical Ventilation in a Simulated Pediatric Lung Model with Exhaled Humidity

Acutely ill children may transition between spontaneous breathing (SB), noninvasive ventilation (NIV), and mechanical ventilation (MV), and commonly receive the same drug dosage with each type of ventilatory support and interface. This study aims to determine the aerosol deposition with jet (JN) and mesh nebulizers (MN) during SB, NIV, and MV using a pediatric lung model. Drug delivery with JN (Mistymax10) and MN (Aerogen Solo) was compared during SB, NIV, and MV using three different lung models set to simulate the same breathing parameters (Vt 250 mL, RR 20 bpm, I:E ratio 1:3). A heated humidifier was placed between the filter and test lung to simulate exhaled humidity (35 ± 2 °C, 100% RH) with all lung models. Albuterol sulfate (2.5 mg/3 mL) was delivered, and the drug deposited on an absolute filter was eluted and analyzed with spectrophotometry. Aerosol delivery with JN was not significantly different during MV, NIV, and SB (p = 0.075), while inhaled dose obtained with MN during MV was greater than NIV and SB (p = 0.001). The delivery efficiency of MN was up to 3-fold more than JN during MV (p = 0.008), NIV (p = 0.005), and SB (p = 0.009). Delivered dose with JN was similar during MV, NIV, and SB, although the delivery efficiency of MN differs with different modes of ventilation.

Delivered dose with jet and mesh nebulisers during spontaneous breathing, noninvasive ventilation, and mechanical ventilation using adult lung models

What is the delivered dose with jet (JN) and mesh nebulizers (MN) during spontaneous breathing (SB), noninvasive ventilation (NIV), and mechanical ventilation (MV) using an adult lung model with exhaled humidity (EH)? Albuterol sulfate (2.5 mg·3 mL−1) delivery with JN (Mistymax10) and MN (AerogenSolo) was compared during SB, NIV, and MV using breathing parameters (Vt=450 mL, RR=20 bpm, I:E=1:3) with three lung models simulating EH. A manikin was attached to a sinusoidal pump via a filter at the bronchi to simulate an adult with SB. A ventilator (V60) was attached via a facemask to a manikin with a filter at the bronchi connected to a test lung to simulate an adult receiving NIV. A ventilator-dependent adult was simulated through a ventilator (Servo i) operated with a heated humidifier (Fisher&Paykel) attached to an ETT with a heated-wire circuit. The ETT was inserted into a filter (RespirgardII). A heated humidifier was placed between the filter and test lung to simulate EH (35±2° C, 100% RH). Nebulizers were placed at the Y-piece of the inspiratory limb during MV and positioned between the facemask and the leak-port during NIV. A mouthpiece was used during SB. The delivered dose was collected in an absolute filter that was attached to the bronchi of the mannequin during each aerosol treatment and measured with spectrohoptometry. Drug delivery during MV was significantly greater than NIV and SB with MN (p=0.0001) but not with JN (p=0.384). Delivery efficiency of MN was greater than JN during MV (p=0.0001), NIV (p=0.0001), and SB (p=0.0001). Drug delivery with MN was greater and differed between MV, NIV, and SB, while deposition was low with JN and similar between the modes of ventilation tested.