External Dead Space in Ventilated COVID-19 Patients

Influence of External Dead Space on Volumetric Capnography Derived Parameters in Mechanically Ventilated COVID-19 Patients

The objective is to investigate the efficacy of volumetric capnography to detect changes in dead space, CO2 elimination and shape factor parameters before and after disconnection of external dead space in ventilated COVID-19 patients.

Study Overview

• Status: Completed
• Conditions: Coronavirus; ARDS, Human
• Intervention / Treatment: Other: Removal of dead space filter

Detailed Description

Covid-19 patients under mechanical ventilation are currently managed with a lung protective strategy derived from ARDSnet recommendations. In order to minimize the risk of spread of coronavirus, filters and associated respiratory tubing are incorporated to the breathing circuit, thus increasing apparatus dead space with subsequent increase in dead space ventilation. Considering the already often compromised ability for these patients to adequately clear carbon dioxide (VCO2), adding an external dead space can potentially have a substantial impact on CO2 homeostasis. The study will use volumetric capnography (Vcap) to investigate the influence of external dead space on VCO2 and calculated alveolar dead space.

Objective: 1) To investigate the efficacy of Vcap to detect changes in dead space, VCO2 and shape factor parameters before and after disconnection of external dead space.

2) To register the external dead space impact on arterial carbon dioxide tension (PaCO2).

3) To calculate the alveolar dead space based on Vcap data and arterial blood gas analysis results.

Design and setting: Prospective observational study in an intensive care center for Covid-19 patients in a university hospital.

Patients: Covid-19 positive patients of all age groups under mechanical ventilation. Exclusion criteria is ongoing ECMO treatment

Measurements and results: Vcap and Tcap parameters will be registered during mechanical ventilation and correlated to an arterial blood gas sample. Part of the apparatus dead space will then be reduced via removal of the heat and moister exchange filter (HME) with added tubing resulting in a reduction in volume of approximately 80 ml (i.e. the known volume of the HME filter and associated tubing). After the apparatus dead space is removed, the Vcap will be recorded for approximately 15 minutes and an arterial blood gas will be drawn at the end of the period. The HME and associated tubing will then be reattached to the breathing circuit and Vcap and Tcap parameters will be recorded for approximately 30 minutes and an arterial blood gas will be drawn. Vcap data will be analyzed for dead space, slope of phase III, VCO2 and associated shape factor parameters and compared with Tcap parameters. Changes in Vcap parameters will be tested for statistical significance using one and two-way ANOVA for repeated measures and Bland-Altman analysis will be used for comparison.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Stockholm, Sweden, 171 76
    • Karolinska University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

Covid-19 positive patients of all age groups under mechanical ventilation

-

Exclusion Criteria:

• Exclusion criteria is ongoing ECMO treatment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: dead space removal; external dead space will be removed and Vcap parameters (VCO2, PaCO2 and alveolar dead space) recorded before and after.	Other: Removal of dead space filter; Dead space filters will be removed and Vcap parameters (VCO2 ml/min, PaCO2 kPa, alveolar dead space in ml) recorded before and after removal

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in carbon dioxide elimination (VCO2) i.e. ml CO2 eliminated/minute	VCO2 is expected to increase after removal of the external dead space	60 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in alveolar dead space (a Vcap derived parameter)	Removing the external dead space is expected to decrease alveolar dead space (ml)	60 minutes
Changes in arterial carbon dioxide tension (PaCO2).	Removal of external dead space is expected to decrease PaCO2 (kPa).	60 minutes

Collaborators and Investigators

• Sponsor: Karolinska Institutet
• Collaborators: Region Stockholm
• Investigators: Study Director: Björn Persson, MD PhD, Karolinska University

Study record dates

Study Major Dates

• Study Start (Actual): June 9, 2020
• Primary Completion (Actual): June 25, 2020
• Study Completion (Actual): May 27, 2021

Study Registration Dates

• First Submitted: June 7, 2020
• First Submitted That Met QC Criteria: June 8, 2020
• First Posted (Actual): June 9, 2020

Study Record Updates

• Last Update Posted (Actual): May 28, 2021
• Last Update Submitted That Met QC Criteria: May 27, 2021
• Last Verified: May 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Lung Diseases; Respiratory Distress Syndrome
• Other Study ID Numbers: Karolinska

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No