The Diagnostic Value of End-Tidal CO2 in Patients Diagnosed With Pneumothorax

The Diagnostic Value of End-Tidal CO2 in Patients Diagnosed With Pneumothorax in the Emergency Department and Its Role in Predicting Patient Outcomes

Pneumothorax (PTX) is defined as the accumulation of air in the pleural space. PTX can cause a disruption in the perfusion of lung tissue in the affected area and increase intrathoracic pressure, potentially leading to obstruction of venous return and, consequently, posing a life-threatening condition. Therefore, PTX requiring urgent intervention is a significant concern in emergency departments.

End-tidal carbon dioxide (ETCO2) provides insight into carbon dioxide levels resulting from lung perfusion and serves as a respiratory parameter informing the prognosis of various critical illnesses. One of the most important factors determining lung perfusion is the effective lung area. Among the crucial issues for emergency departments are PTX cases, which typically regress following urgent intervention, leading to the establishment of an effective lung area. Hypotheses have been proposed in the literature suggesting that ETCO2 may be affected in PTX cases due to the relationship between effective lung area and ETCO2.

In this study, investigetors aimed to investigate changes in ETCO2 levels following tube thoracostomy applied to PTX cases.

Study Overview

• Status: Completed
• Conditions: Pneumothorax
• Intervention / Treatment: Procedure: End-tidal CO2 monitor

Detailed Description

In the study, a GE brand patient monitor (GE Medical Systems Information Technologies, Germany) was used for vital parameters, and a Medtronic brand Capnostream 35 respiratory monitor device (Oridion Medical 1987 Ltd., Israel) was used for ETCO2 measurement. Patients' ETCO2 measurements were performed using a device that measures ETCO2 levels in breaths delivered through the mouth and nose (sidestream measurement). ETCO2 values were measured before tube thoracostomy placement and at 2 and 4 hours after placement. The diagnosis of pneumothorax was confirmed by chest X-ray. Tube thoracostomy was performed by chest surgeons or emergency physicians. Indications for tube thoracostomy were determined by chest surgery doctors.

Patients' age, gender, height, weight, vital signs, smoking history, pneumothorax causes, lateral and apex collapse amount (in mm), procedures performed, ETCO2 values before and after tube insertion at 2 and 4 hours, hemogram, biochemistry, and blood gas values were recorded on case report forms. Additionally, patients' lengths of stay were recorded using archive numbers through the hospital automation system.

On chest X-ray, a distance greater than 2 cm between the parietal and visceral pleura at the hilum level according to British guidelines or a distance greater than 3 cm from the apex according to American guidelines was defined as a large pneumothorax. Additionally, the percentage of PTX volume for patients was calculated using the Collins method. The PTX percentage was calculated using the formula "%Collins = '4.2 + 4.7(a + b + c)'", where 'a' is the maximum apical interpleural distance, 'b' is the interpleural distance at the midpoint of the upper half of the lung, and 'c' is the interpleural distance at the midpoint of the lower half of the lung.

Neutrophil Lymphocyte Ratio (NLR) and Platelet Lymphocyte Ratio (PLR) calculations were performed.

The initial ETCO2 (ETCO2-0) was defined as the ETCO2 measured at the emergency department visit. PaCO2 was defined as the partial pressure of carbon dioxide measured with the first blood gas analysis taken at the emergency department visit. After lung expansion, ETCO2 was defined as the average value of ETCO2 measured 2 to 4 hours after tube thoracotomy (ETCO2-1/ETCO2-2, respectively). The increase in ETCO2 after expansion was defined as the increase in ETCO2 after closed tube thoracotomy (ETCO2 increase after drainage = ETCO2 after tube thoracotomy - initial ETCO2). The change from ETCO2-0 to ETCO2-1 was determined as deltaETCO2-1 (ΔETCO2-1), and the change from ETCO2-0 to ETCO2-2 was determined as ΔETCO2-2.

• Study Type: Observational
• Enrollment (Actual): 43

Contacts and Locations

Study Locations

• Turkey
  • Çankaya
    • Ankara, Çankaya, Turkey, 06170
      • Ankara Bilkent Şehir Hastanesi

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

The study included patients aged 18 and over, without any comorbidities, diagnosed with spontaneous or traumatic pneumothorax, who underwent tube thoracostomy, and had no other organ damage or injury.

Description

Inclusion Criteria:

• Patients aged 18 and over
• Individuals without comorbidities
• Those diagnosed with spontaneous or traumatic pneumothorax
• Patients who underwent tube thoracostomy
• Individuals without other organ damage or injury

Exclusion Criteria:

• Patients under 18 years of age or over 65 years of age
• Patients who refuse to participate in the study
• Pregnant women
• Individuals diagnosed with acute/chronic lung disease
• Those with a history of advanced heart failure
• Individuals with advanced systemic disease
• Patients with a history of malignancy (cancer)
• Individuals with chronic liver disease
• Those using sedative and analgesic neuro-psychiatric drugs
• Patients with a history of psychological or neurological disorders
• Individuals with acute organ damage or failure

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ETCO2-0	It was defined as the end-tidal CO2 (ETCO2) measured at the emergency department visit.	Five minutes have passed since the emergency room application.
ΔETCO2-1	The change in ETCO2-1 compared to ETCO2-0.	Two hours after the emergency room application.
ΔETCO2-2	The change in ETCO2-2 compared to ETCO2-0.	Four hours after the emergency room application.
ETCO2-1	End-tidal CO2 measured 2 hours after emergency department admission.	Two hours after the emergency room application.
ETCO2-2	End-tidal CO2 measured 2 hours after emergency department admission.	Four hours after the emergency room application.

Collaborators and Investigators

• Sponsor: Ankara City Hospital Bilkent

Publications and helpful links

General Publications

• Lee GM, Kim YW, Lee S, Do HH, Seo JS, Lee JH. End-Tidal Carbon Dioxide Monitoring for Spontaneous Pneumothorax. Emerg Med Int. 2021 Jun 14;2021:9976543. doi: 10.1155/2021/9976543. eCollection 2021.

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2023
• Primary Completion (Actual): February 6, 2024
• Study Completion (Actual): February 13, 2024

Study Registration Dates

• First Submitted: February 15, 2024
• First Submitted That Met QC Criteria: February 22, 2024
• First Posted (Estimated): February 26, 2024

Study Record Updates

• Last Update Posted (Estimated): February 26, 2024
• Last Update Submitted That Met QC Criteria: February 22, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Pleural Diseases; Pneumothorax
• Other Study ID Numbers: E1-23-3870 ptx endtidalco2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Not currently planned.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No