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.

Coronavirus Disease 2019: Anesthesia Machine Circuit Pressure During Use as an Improvised Intensive Care Unit Ventilator.

BACKGROUND: Use of anesthesia machines as improvised intensive care unit (ICU) ventilators may occur in locations where waste anesthesia gas suction (WAGS) is unavailable. Anecdotal reports suggest as much as 18 cm H2O positive end-expiratory pressure (PEEP) being inadvertently applied under these circumstances, accompanied by inaccurate pressure readings by the anesthesia machine. We hypothesized that resistance within closed anesthesia gas scavenging systems (AGSS) disconnected from WAGS may inadvertently increase circuit pressures. METHODS: An anesthesia machine was connected to an anesthesia breathing circuit, a reference manometer, and a standard bag reservoir to simulate a lung. Ventilation was initiated as follows: volume control, tidal volume (TV) 500 mL, respiratory rate 12, ratio of inspiration to expiration times (I:E) 1:1.9, fraction of inspired oxygen (Fio2) 1.0, fresh gas flow (FGF) rate 2.0 liters per minute (LPM), and PEEP 0 cm H2O. After engaging the ventilator, PEEP and peak inspiratory pressure (PIP) were measured by the reference manometer and the anesthesia machine display simultaneously. The process was repeated using prescribed PEEP levels of 5, 10, 15, and 20 cm H2O. Measurements were repeated with the WAGS disconnected and then were performed again at FGF of 4, 6, 8, 10, and 15 LPM. This process was completed on 3 anesthesia machines: Dräger Perseus A500, Dräger Apollo, and the GE Avance CS2. Simple linear regression was used to assess differences. RESULTS: Utilizing nonparametric Bland-Altman analysis, the reference and machine manometer measurements of PIP demonstrated median differences of -0.40 cm H2O (95% limits of agreement [LOA], -1.00 to 0.55) for the Dräger Apollo, -0.40 cm H2O (95% LOA, -1.10 to 0.41) for the Dräger Perseus, and 1.70 cm H2O (95% LOA, 0.80-3.00) for the GE Avance CS2. At FGF 2 LPM and PEEP 0 cm H2O with the WAGS disconnected, the Dräger Apollo had a difference in PEEP of 0.02 cm H2O (95% confidence interval [CI], -0.04 to 0.08; P = .53); the Dräger Perseus A500, <0.0001 cm H2O (95% CI, -0.11 to 0.11; P = 1.00); and the GE Avance CS2, 8.62 cm H2O (95% CI, 8.55-8.69; P < .0001). After removing the hose connected to the AGSS and the visual indicator bag on the GE Avance CS2, the PEEP difference was 0.12 cm H2O (95% CI, 0.059-0.181; P = .0002). CONCLUSIONS: Displayed airway pressure measurements are clinically accurate in the setting of disconnected WAGS. The Dräger Perseus A500 and Apollo with open scavenging systems do not deliver inadvertent continuous positive airway pressure (CPAP) with WAGS disconnected, but the GE Avance CS2 with a closed AGSS does. This increase in airway pressure can be mitigated by the manufacturer's recommended alterations. Anesthesiologists should be aware of the potential clinically important increases in pressure that may be inadvertently delivered on some anesthesia machines, should the WAGS not be properly connected.

Time to adapt in the pandemic era: a prospective randomized non -inferiority study comparing time to intubate with and without the barrier box.

BACKGROUND: The challenges posed by the spread of COVID-19 disease through aerosols have compelled anesthesiologists to modify their airway management practices. Devices such as barrier boxes are being considered as potential adjuncts to full PPE's to limit the aerosol spread. Usage of the barrier box raises concerns of delay in time to intubate (TTI). We designed our study to determine if using a barrier box with glidescope delays TTI within acceptable parameters to make relevant clinical conclusions. METHODS: Seventy-eight patients were enrolled in this prospective non-inferiority controlled trial and were randomly allocated to either group C (without the barrier box) or the study group BB (using barrier box). The primary measured endpoint is time to intubate (TTI), which is defined as time taken from loss of twitches confirmed with a peripheral nerve stimulator to confirmation of end-tidal CO 2. 15 s was used as non-inferiority margin for the purpose of the study. We used an unpaired two-sample single-sided t-test to test our non- inferiority hypothesis (H 0: Mean TTI diff ≥15 s, H A: Mean TTI diff < 15 s). Secondary endpoints include the number of attempts at intubation, lowest oxygen saturation during induction, and the need for bag-mask ventilation. RESULTS: Mean TTI in group C was 42 s (CI 19.2 to 64.8) vs. 52.1 s (CI 26.1 to 78) in group BB. The difference in mean TTI was 10.1 s (CI -∞ to 14.9). We rejected the null hypothesis and concluded with 95% confidence that the difference of the mean TTI between the groups is less than < 15 s (95% CI -∞ to 14.9,p = 0.0461). Our induction times were comparable (67.7 vs. 65.9 s).100% of our patients were intubated on the first attempt in both groups. None of our patients needed rescue breaths. CONCLUSIONS: We conclude that in patients with normal airway exam, scheduled for elective surgeries, our barrier box did not cause any clinically significant delay in TTI when airway manipulation is performed by well-trained providers. The study was retrospectively registered at clinicaltrials.gov (NCT04411056) on May 27, 2020.

Use of Anesthesia Machines in a Critical Care Setting During the Coronavirus Disease 2019 Pandemic.

The coronavirus disease 2019 (COVID-19) pandemic created an unprecedented need for mechanical ventilation in critically ill patients. To meet this increased demand, some facilities were forced to use anesthesia gas machines (AGMs) as intensive care unit (ICU) ventilators. While an off-label use, AGM manufacturers, the Anesthesia Patient Safety Foundation, and the American Society of Anesthesiologists have guidelines for AGM use in the ICU, however, there is scant literature describing their use. This article describes our experiences at New York University Langone Medical Center using AGMs in the ICU for ventilating critically ill COVID-19 patients.