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.

Preparation of Dräger Atlan A350 and General Electric Healthcare Carestation 650 anesthesia workstations for malignant hyperthermia susceptible patients

Background Patients at risk of malignant hyperthermia need trigger-free anesthesia. Therefore, anesthesia machines prepared for safe use in predisposed patients should be free of volatile anesthetics. The washout time depends on the composition of rubber and plastic in the anesthesia machine. Therefore, new anesthesia machines should be evaluated regarding the safe preparation for trigger-free anesthesia. This study investigates wash out procedures of volatile anesthetics for two new anesthetic workstations: Dräger Atlan A350 and General Electric Healthcare (GE) Carestation 650 and compare it with preparation using activated charcoal filters (ACF). Methods A Dräger Atlan and a Carestation 650 were contaminated with 4% sevoflurane for 90 min. The machines were decontaminated with method (M1): using ACF, method 2 (M2): a wash out method that included exchange of internal parts, breathing circuits and soda lime canister followed by ventilating a test lung using a preliminary protocol provided by Dräger or method 3 (M3): a universal wash out instruction of GE, method 4 (M4): M3 plus exchange of breathing system and bellows. Decontamination was followed by a simulated trigger-free ventilation. All experiments were repeated with 8% desflurane contaminated machines. Volatile anesthetics were detected with a closed gas loop high-resolution ion mobility spectrometer with gas chromatographic pre-separation attached to the bacterial filter of the breathing circuits. Primary outcome was time until < 5 ppm of volatile anesthetics and total preparation time. Results Time to < 5 ppm for the Atlan was 17 min (desflurane) and 50 min (sevoflurane), wash out continued for a total of 60 min according to protocol resulting in a total preparation time of 96-122 min. The Carestation needed 66 min (desflurane) and 24 min (sevoflurane) which could be abbreviated to 24 min (desflurane) if breathing system and bellows were changed. Total preparation time was 30-73 min. When using active charcoal filters time to < 5 ppm was 0 min for both machines, and total preparation time < 5 min. Conclusion Both wash out protocols resulted in a significant reduction of trace gas concentrations. However, due to the complexity of the protocols and prolonged total preparation time, feasibility in clinical practice remains questionable. Especially when time is limited preparation of the anesthetic machines using ACF remain superior.

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.

Comparing Ventilation Parameters for COVID-19 Patients Using Both Long-Term ICU and Anesthetic Ventilators in Times of Shortage

In the first months of the COVID-19 pandemic in Europe, many patients were treated in hospitals using mechanical ventilation. However, due to a shortage of ICU ventilators, hospitals worldwide needed to deploy anesthesia machines for ICU ventilation (which is off-label use). A joint guidance was written to apply anesthesia machines for long-term ventilation. The goal of this research is to retrospectively evaluate the differences in measurable ventilation parameters between the ICU ventilator and the anesthesia machine as used for COVID-19 patients. In this study, we included 32 patients treated in March and April 2020, who had more than 3 days of mechanical ventilation, either in the regular ICU with ICU ventilators (Hamilton S1), or in the temporary emergency ICU with anesthetic ventilators (Aisys, GE). The data acquired during regular clinical treatment was collected from the Patient Data Management Systems. Available ventilation parameters (pressures and volumes: PEEP, Ppeak, Pinsp, Vtidal), monitored parameters EtCO2, SpO2, derived compliance C, and resistance R were processed and analyzed. A sub-analysis was performed to compare closed-loop ventilation (INTELLiVENT-ASV) to other ventilation modes. The results showed no major differences in the compared parameters, except for Pinsp. PEEP was reduced over time in the with Hamilton treated patients. This is most likely attributed to changing clinical protocol as more clinical experience and literature became available. A comparison of compliance between the 2 ventilators could not be made due to variances in the measurement of compliance. Closed loop ventilation could be used in 79% of the time, resulting in more stable EtCO2. From the analysis it can be concluded that the off-label usage of the anesthetic ventilator in our hospital did not result in differences in ventilation parameters compared to the ICU treatment in the first 4 days of ventilation.

The repurposed use of anesthesia machines to ventilate critically ill patients with coronavirus disease 2019 (COVID-19)

Background The surge of critically ill patients due to the coronavirus disease-2019 (COVID-19) overwhelmed critical care capacity in areas of northern Italy. Anesthesia machines have been used as alternatives to traditional ICU mechanical ventilators. However, the outcomes for patients with COVID-19 respiratory failure cared for with Anesthesia Machines is currently unknow. We hypothesized that COVID-19 patients receiving care with Anesthesia Machines would have worse outcomes compared to standard practice. Methods We designed a retrospective study of patients admitted with a confirmed COVID-19 diagnosis at a large tertiary urban hospital in northern Italy. Two care units were included: a 27-bed standard ICU and a 15-bed temporary unit emergently opened in an operating room setting. Intubated patients assigned to Anesthesia Machines (AM group) were compared to a control cohort treated with standard mechanical ventilators (ICU-VENT group). Outcomes were assessed at 60-day follow-up. A multivariable Cox regression analysis of risk factors between survivors and non-survivors was conducted to determine the adjusted risk of death for patients assigned to AM group. Results Complete daily data from 89 mechanically ventilated patients consecutively admitted to the two units were analyzed. Seventeen patients were included in the AM group, whereas 72 were in the ICU-VENT group. Disease severity and intensity of treatment were comparable between the two groups. The 60-day mortality was significantly higher in the AM group compared to the ICU-vent group (12/17 vs. 27/72, 70.6% vs. 37.5%, respectively, p = 0.016). Allocation to AM group was associated with a significantly increased risk of death after adjusting for covariates (HR 4.05, 95% CI: 1.75–9.33, p = 0.001). Several incidents and complications were reported with Anesthesia Machine care, raising safety concerns. Conclusions Our results support the hypothesis that care associated with the use of Anesthesia Machines is inadequate to provide long-term critical care to patients with COVID-19. Added safety risks must be considered if no other option is available to treat severely ill patients during the ongoing pandemic. Clinical trial number Not applicable.

Descripción y seguimiento de pacientes COVID-19 en ventilación mecánica en unidades convertidas dirigidas por anestesiólogos: Clínica Alemana de Santiago

Introduction: The high demand for critical care beds and the need for mechanical ventilation generated by the pandemia of COVID-19 led the Ministry of Health of Chile to authorize both the conversion of beds and the use of anesthesia machines to mechanically ventilate COVID-19 patients. At Clínica Alemana de Santiago (CAS), these converted units were managed by non-intensivist anesthesiologists with technical support from the Intensive Care Unit (ICU). The objective of this study was to compare the survival rate of patients managed at converted and traditional ICU units. The secondary objective was to analyze the factors that may affect morbidity and mortality of these patients. Method: This prospective observational study included mechanically ventilated COVID-19 patients in both traditional and converted units. Patients were followed for 90 days starting at intubation day. Survival rate was determined at 30 and 90 days. A survival analysis was then performed. Results: 41 and 42 patients were admitted to CAS trough converted and traditional ICU units, respectively, between May 24 and June 30, 2020. There was not significant difference in survival rate between converted and traditional ICU units. Age (HR 1.1 per year) and SOFA (HR 1.4 per point) were associated with survival. Conclusions: At CAS, the survival of COVID-19 patients who required mechanical ventilation in converted units was not different as in those patients treated in traditional ICU units. Both age and SOFA were variables that can inform about prognosis of these patients.

The repurposed use of anesthesia machines to ventilate critically ill patients with Coronavirus Disease 2019 (COVID-19)

BackgroundThe surge of critically ill patients due to the coronavirus disease-2019 (COVID-19) overwhelmed critical care capacity in areas of northern Italy. Anesthesia machines have been used as alternatives to traditional ICU mechanical ventilators. However, the outcomes for patients with COVID-19 respiratory failure cared for with Anesthesia Machines is currently unknow. We hypothesized that COVID-19 patients receiving care with Anesthesia Machines would have worse outcomes compared to standard practice.MethodsWe designed a retrospective study of patients admitted with a confirmed COVID-19 diagnosis at a large tertiary urban hospital in northern Italy. Two care units were included: a 27-bed standard ICU and a 15-bed temporary unit emergently opened in an operating room setting. Intubated patients assigned to Anesthesia Machines (AM group) were compared to a control cohort treated with standard mechanical ventilators (ICU-VENT group). Outcomes were assessed at 60-day follow-up. A multivariable Cox regression analysis of risk factors between survivors and non-survivors was conducted to determine the adjusted risk of death for patients assigned to AM group.ResultsComplete daily data from 89 mechanically ventilated patients consecutively admitted to the two units were analyzed. Seventeen patients were included in the AM group, whereas 72 were in the ICU-VENT group. Disease severity and intensity of treatment were comparable between the two groups. The 60-day mortality was significantly higher in the AM group compared to the ICU-vent group (12/17 vs. 27/72, 70.6% vs. 37.5%, respectively, p = 0.016). Allocation to AM group was associated with a significantly increased risk of death after adjusting for covariates (HR 4.05, 95% CI: 1.75–9.33, p = 0.001). Several incidents and complications were reported with Anesthesia Machine care, raising safety concerns.ConclusionsOur results support the hypothesis that care associated with the use of Anesthesia Machines is inadequate to provide long-term critical care to patients with COVID-19. Added safety risks must be considered if no other option is available to treat severely ill patients during the ongoing pandemic.Clinical Trial NumberNot applicable

Successful anesthetic management of separation surgery for pygopagus conjoined twins: a case report

Background Conjoined twins are an extremely rare congenital occurrence, and anesthetic management for surgical separation presents unique challenges for anesthesiologists. Case presentation Five-month-old male pygopagus conjoined twins underwent separation surgery. We performed anesthesia induction in the supine position and surgery in the prone position. This presented a challenge because the transition from supine to prone position reversed the positional relationship between the two babies, resulting in crossing of the respiratory circuits and monitors. To solve the problem, we used anesthesia machines and monitors on the opposite side of each baby during anesthesia induction. The positional relationship between the twins and anesthesia machines and monitors normalized after the change to the prone position. Following the separation surgery, the twins were discharged without any complications. Conclusions Our method of using opposite side anesthetic machines and monitors for anesthesia induction was useful for the safe anesthetic management of pygopagus conjoined twins.

The method of automated adjustment and controlled maintenance of surgical stage of anesthesia in modern anesthesia machines

The method of automatical adjustment controlled maintenance of the surgical stage of anesthesia of patient during general anesthesia by means of volatile anesthetic dosage regulation depending on BIS level is described and explained. There was conducted a theoretical analysis of possibilities and perspectives of anesthesia depth’s automatical adjustment during general anesthesia by bispectral index individual monitoring depending on volatile anesthetic dosage and individual patient’s condition along with extent of surgical intervention. The possibilities of currently available medical devices allowing to implement the method into the practice have been analyzed. The technical explanation of interaction between modern volatile anesthetic vaporizer and bispectral index monitoring by feedback from integrated microprocessor, breathing circuit and multiple gas monitor of anesthesia machine and microprocessor of vaporizer has been presented.