Influence of varying inspired oxygen tensions on the pulmonary venous admixture (shunt) of mechanically ventilated patients

Abstract Background Mechanically ventilated patients with COVID-19 have a mortality of 24–53%, in part due to distal mucopurulent secretions interfering with ventilation. DNA from neutrophil extracellular traps (NETs) contribute to the viscosity of mucopurulent secretions and NETs are found in the serum of COVID-19 patients. Dornase alfa is recombinant human DNase 1 and is used to digest DNA in mucoid sputum. Here, we report a single-center case series where dornase alfa was co-administered with albuterol through an in-line nebulizer system. Methods Demographic and clinical data were collected from the electronic medical records of five mechanically ventilated patients with COVID-19—including three requiring veno-venous extracorporeal membrane oxygenation—treated with nebulized in-line endotracheal dornase alfa and albuterol, between March 31 and April 24, 2020. Data on tolerability and response were analyzed. Results The fraction of inspired oxygen requirements was reduced for all five patients after initiating dornase alfa administration. All patients were successfully extubated, discharged from hospital and remain alive. No drug-associated toxicities were identified. Conclusions Results suggest that dornase alfa will be well-tolerated by patients with severe COVID-19. Clinical trials are required to formally test the dosing, safety, and efficacy of dornase alfa in COVID-19, and several have been recently registered.

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Knobmanship: Dialing Up Understanding of VAE Triggers

Antimicrobial Stewardship & Healthcare Epidemiology ◽

10.1017/ash.2021.158 ◽

2021 ◽

Vol 1 (S1) ◽

pp. s80-s81

Author(s):

Kelly Cawcutt ◽

Mark Rupp ◽

Lauren Musil

Keyword(s):

Chart Review ◽

Clinical Care ◽

Trigger Points ◽

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Review Period ◽

Fraction Of Inspired Oxygen ◽

Provider Bias ◽

Inspired Oxygen ◽

Ventilated Patients

Background: Mechanical ventilation is a lifesaving therapy for critically ill patients. Hospitals perform surveillance for the NHSN for ventilator-associated events (VAE) by monitoring mechanically ventilated patients for metrics that are generally thought to be objective and preventable and that lead to poor patient outcomes. The VAE definition is met in a stepwise manner; initially, a ventilator-associated condition (VAC) is triggered with an increase in positive end-expiratory pressure (PEEP, >3 cm H2O) or fraction of inspired oxygen (FIO2, 0.20 or 20 points) after a period of stability or improvement on the ventilator. We believe that many reported VAEs could be avoided by provider and respiratory therapy attention to “knobmanship.” We define knobmanship as knowledge of the VAE definition and trigger points combined with appropriate clinical care for mechanically ventilated patients while avoiding unnecessary triggering of the VAE definition by avoiding small unneeded changes in PEEP or FIO2. Methods: We performed a chart review of 283 patients who had a reported VAE to the NHSN between January 1, 2019, and December 31, 2020. We collected data including type of VAE, VAE triggering criteria, and clinical course. Results: Of the 283 VAEs, 59 were triggered by a PEEP increase from 5 to 8 with stable or decreasing FIO2. Of the 59 VAEs, 33 were VACs, 18 were infection-related ventilator- associated complications (IVACs), and 8 were possible ventilator-associated pneumonia (PVAP). Most of these transient changes in PEEP were deemed clinically unnecessary. A 21% reduction of VAEs reported to the NSHN over the 2-year review period could have been avoided by knobmanship. Conclusions: The VAE definition may often be triggered by provider bias to the ventilator settings rather than what the patient’s clinical-condition requires. Attention to knobmanship may result in substantial decrease in reported VAE.Funding: NoDisclosures: None

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On the Transition from Control Modes to Spontaneous Modes during ECMO

Journal of Clinical Medicine ◽

10.3390/jcm10051001 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1001

Author(s):

Krista Stephens ◽

Nathan Mitchell ◽

Sean Overton ◽

Joseph E. Tonna

Keyword(s):

Respiratory Rate ◽

Multivariate Regression ◽

Arterial Oxygen ◽

High Fidelity ◽

Positive End Expiratory Pressure ◽

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Fraction Of Inspired Oxygen ◽

Inspired Oxygen ◽

Ventilated Patients

The transition from control modes to spontaneous modes is ubiquitous for mechanically ventilated patients yet there is little data describing the changes and patterns that occur to breathing during this transition for patients on ECMO. We identified high fidelity data among a diverse cohort of 419 mechanically ventilated patients on ECMO. We examined every ventilator change, describing the differences in >30,000 sets of original ventilator observations, focused around the time of transition from control modes to spontaneous modes. We performed multivariate regression with mixed effects, clustered by patient, to examine changes in ventilator characteristics within patients, including a subset among patients with low compliance (<30 milliliters (mL)/centimeters water (cmH2O)). We found that during the transition to spontaneous modes among patients with low compliance, patients exhibited greater tidal volumes (471 mL (364,585) vs. 425 mL (320,527); p < 0.0001), higher respiratory rate (23 breaths per minute (bpm) (18,28) vs. 18 bpm (14,23); p = 0.003), greater mechanical power (elastic component) (0.08 mL/(cmH2O × minute) (0.05,0.12) vs. 0.05 mL/(cmH2O × minute) (0.02,0.09); p < 0.0001) (range 0 to 1.4), and lower positive end expiratory pressure (PEEP) (6 cmH2O (5,8) vs. 10 cmH2O (8,11); p < 0.0001). For patients on control modes, the combination of increased tidal volume and increased respiratory rate was temporally associated with significantly low partial pressure of arterial oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio (p < 0.0001). These changes in ventilator parameters warrant prospective study, as they may be associated with worsened lung injury.

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Association Between Peripheral Blood Oxygen Saturation (SpO2)/Fraction of Inspired Oxygen (FiO2) Ratio Time at Risk and Hospital Mortality in Mechanically Ventilated Patients

The Permanente Journal ◽

10.7812/tpp/19.113 ◽

2020 ◽

Cited By ~ 1

Keyword(s):

Hospital Mortality ◽

Oxygen Saturation ◽

Peripheral Blood ◽

Blood Oxygen ◽

Blood Oxygen Saturation ◽

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Fraction Of Inspired Oxygen ◽

Inspired Oxygen ◽

Ventilated Patients

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The effects of manual hyperflation using self-inflating manual resuscitation bags on arterial oxygen tensions and lung compliance - Ameta-analysis of the literature

South African Journal of Physiotherapy ◽

10.4102/sajp.v56i1.545 ◽

2000 ◽

Vol 56 (1) ◽

pp. 7-16 ◽

Cited By ~ 4

Author(s):

M. Barker ◽

C. J. Eales

Keyword(s):

Meta Analysis ◽

Lung Compliance ◽

Arterial Oxygen ◽

Mean Values ◽

Mechanically Ventilated ◽

Mechanically Ventilated Patients ◽

Therapeutic Value ◽

The Mean ◽

Oxygen Tensions ◽

Ventilated Patients

The self-inflating manual resuscitation bag (MRB) is a modality which is commonly used by physiotherapists to manually hyperinflate the lungs of mechanically ventilated patients. There is limited scientific evidence to support its therapeutic use and the literature is not in agreement as to the effects of manual hyperinflation. A meta-analysis of the current research on humans has been conducted to investigate the effects of this modality on arterial oxygen tensions and lung compliance. All published studies evaluating the effects of manual hyperinflation (or bagging) on arterial oxygen tensions and/or lung compliance on mechanically ventilated patients have been retrieved. Only studies which reported results in terms of mean values and standard deviation or standard error of the mean could be used in this analysis. Eleven studies were identified between the time period 1968 -1995. Seven of these studies fitted the inclusion criteria. The mean and standard error of the mean values for arterial oxygen tensions (Pa02) and lung compliance (CL) have been used to calculate the 95% confidence intervals and these results were plotted on a graph. A comparative analysis has been performed on the results of the seven studies. A generally non-significant association between bagging and the Pa02 and CL values was demonstrated. Great discrepancies were identified in the designs of the seven included studies. Since the seven studies included in this meta-analysis show an overall non-significant association, it is reasonable to assume that the therapeutic value of the self-inflating manual resuscitation bag is questionable. The studies presented such divergent designs that they do not offer conclusive evidence. More standardized, multi-centre studies are required to clarify the therapeutic value of this modality. Other methods of recruiting the lungs of critically ill patients during and after physiotherapy intervention, need to be explored.

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