Respired Gases in Patients Post Cardiac Surgery

NCT05531253 | Completed

• 2 other identifiers: 16070IRAS 306400
• Study Type: observational
• Target: 25
• Locations: 1 country
• Sites: 1

Brief Summary

Certain diseases relating to the heart can only be definitively treated with surgery. When untreated, these can lead to heart failure with a lack of supply of oxygen-rich blood to the tissues, leading to damage to other organs. Adults who undergo heart surgery vary greatly in terms of age and relative health. This has significant implications when predicting outcomes in the aftermath of surgery. For example, a 90-year-old man with a variety of comorbidities such as diabetes and high cholesterol who requires a heart valve replacement may have an unfavourable chance of surviving the postoperative period when compared to an 18-year-old woman with no significant medical history undergoing the same procedure. Almost invariably, patients are admitted to an Intensive Care Unit (ICU) following heart surgery. This is done to facilitate close monitoring of the patients' vital organ functions and to also provide organ support if needed. For the heart, this can include the administration of drugs to help a heart pump forcibly, cause blood vessels to contract and increase blood pressure. Patients who have undergone heart surgery have been placed on a mechanical ventilator, following a tube placed in their windpipe. This form of ventilation often continues in ICU for a period of time, depending on the patient's condition. One specific type of ICU level monitoring that occurs in patients who have undergone heart surgery is cardiac output monitoring. This involves a thin tube, called a pulmonary artery catheter, that extends from the skin to the heart, via large blood vessels. Cardiac output monitoring is essential in this patient group to guide organ support and to provide information of how well the heart is functioning. In this observational study, the investigators wish to study patients who have undergone cardiac surgery, are receiving mechanical ventilation and have pulmonary artery catheters inserted. The investigators will collect cardiopulmonary data in these patients and compare these data with values of exhaled and inhaled gases (oxygen and carbon dioxide) over the same time period. This will enable the investigators to investigate the link between cardiopulmonary data and respired gas values. A better understanding of this link between cardiopulmonary function and oxygen/carbon dioxide values will then inform future studies aiming to determine the effect of various interventions in similar patient groups.

Conditions

Critically Ill; Cardiac Disease; Mitral Valve Disease

Keywords

pulmonary artery catheter; cardiac output; mixed venous oxygen saturation; oxygen consumption; Fick

Outcome Measures

Primary Outcomes (2)

• Oxygen (O2)

  Measured from the OGA

  Up to 12 hours

• Carbon dioxide (CO2)

  Measured from the OGA

  Up to 12 hours

Secondary Outcomes (2)

• Mixed venous oxygen saturation

  Up to 12 hours

• Cardiac output

  Up to 12 hours

Study Arms (1)

Main cohort

Patients undergoing cardiac surgery who will have a pulmonary artery catheter in-situ at the time of admission to cardiac intensive care postoperatively.

Other: Data collection using the Optical Gas Analyser

Interventions

Data collection using the Optical Gas Analyser OTHER

To allow the OGA to acquire certain physiological data during the study it will be necessary to slightly vary the tension of oxygen and carbon dioxide for short periods. The changes involved will be of a lesser magnitude than those often seen due to natural variation over time in critically ill patients. The FiO2 will be increased by around 20% from baseline for several minutes; this is a far more modest increase than is seen with the practice of pre-oxygenation - a transitory increase in fraction of inspired oxygen ( FiO2) to 100% - performed regularly in ICU patients to make certain routine interventions safer. The end-tidal CO2 level will also briefly (1-2 min) be altered by around 1 kPa by transient adjustment of the ventilator settings.

Main cohort

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adult patients receiving mechanical ventilation following cardiac surgery

You may qualify if:

• Participant is willing and able to give informed consent for participation in the study.
• Male and female, aged 18 years or above
• Receiving mechanical ventilation via an endotracheal tube in ICU, directly after cardiac surgery
• Have a pulmonary artery catheter in-situ or receive non-invasive cardiac output monitoring

You may not qualify if:

• Patient is receiving palliative care

Sponsors & Collaborators

• University of Oxford: lead

Study Sites (1)

John Radcliffe Hospital

Oxford, Oxfordshire, OX3 9DU, United Kingdom

Location

Related Publications (16)

• Bersten A. Oh's intensive care manual. Elsevier; 2014.

  BACKGROUND

• National Institute for Cardiovascular Outcomes Research, 2020. National Adult Cardiac Surgery Audit (NACSA) 2020 Summary Report (2016/17-2018/19 data). Healthcare Quality Improvement Partnership.

  BACKGROUND

• Savino JS, Hanson CW 3rd, Gardner TJ. Cardiothoracic intensive care: operation and administration. Semin Thorac Cardiovasc Surg. 2000 Oct;12(4):362-70. doi: 10.1053/stcs.2000.20513.

  PMID: 11154731 BACKGROUND

• Rodriguez Ziccardi M, Khalid N. Pulmonary Artery Catheterization. 2023 Aug 28. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from http://www.ncbi.nlm.nih.gov/books/NBK482170/

  PMID: 29489212 BACKGROUND

• Cummings B, Hamilton ML, Ciaffoni L, Pragnell TR, Peverall R, Ritchie GA, Hancock G, Robbins PA. Laser-based absorption spectroscopy as a technique for rapid in-line analysis of respired gas concentrations of O2 and CO2. J Appl Physiol (1985). 2011 Jul;111(1):303-7. doi: 10.1152/japplphysiol.00119.2011. Epub 2011 Apr 21.

  PMID: 21512147 BACKGROUND

• Ciaffoni L, O'Neill DP, Couper JH, Ritchie GA, Hancock G, Robbins PA. In-airway molecular flow sensing: A new technology for continuous, noninvasive monitoring of oxygen consumption in critical care. Sci Adv. 2016 Aug 10;2(8):e1600560. doi: 10.1126/sciadv.1600560. eCollection 2016 Aug.

  PMID: 27532048 BACKGROUND

• Mountain JE, Santer P, O'Neill DP, Smith NMJ, Ciaffoni L, Couper JH, Ritchie GAD, Hancock G, Whiteley JP, Robbins PA. Potential for noninvasive assessment of lung inhomogeneity using highly precise, highly time-resolved measurements of gas exchange. J Appl Physiol (1985). 2018 Mar 1;124(3):615-631. doi: 10.1152/japplphysiol.00745.2017. Epub 2017 Oct 26.

  PMID: 29074714 BACKGROUND

• Magor-Elliott SRM, Fullerton CJ, Richmond G, Ritchie GAD, Robbins PA. A dynamic model of the body gas stores for carbon dioxide, oxygen, and inert gases that incorporates circulatory transport delays to and from the lung. J Appl Physiol (1985). 2021 May 1;130(5):1383-1397. doi: 10.1152/japplphysiol.00764.2020. Epub 2021 Jan 21.

  PMID: 33475459 BACKGROUND

• Pugsley J, Lerner AB. Cardiac output monitoring: is there a gold standard and how do the newer technologies compare? Semin Cardiothorac Vasc Anesth. 2010 Dec;14(4):274-82. doi: 10.1177/1089253210386386. Epub 2010 Nov 7.

  PMID: 21059611 BACKGROUND

• De Maria AN, Raisinghani A. Comparative overview of cardiac output measurement methods: has impedance cardiography come of age? Congest Heart Fail. 2000 Mar-Apr;6(2):60-73. doi: 10.1111/j.1527-5299.2000.80139.x.

  PMID: 12029189 BACKGROUND

• Wilkes AR. Heat and moisture exchangers and breathing system filters: their use in anaesthesia and intensive care. Part 2 - practical use, including problems, and their use with paediatric patients. Anaesthesia. 2011 Jan;66(1):40-51. doi: 10.1111/j.1365-2044.2010.06564.x. Epub 2010 Nov 30.

  PMID: 21118189 BACKGROUND

• Davis K Jr, Evans SL, Campbell RS, Johannigman JA, Luchette FA, Porembka DT, Branson RD. Prolonged use of heat and moisture exchangers does not affect device efficiency or frequency rate of nosocomial pneumonia. Crit Care Med. 2000 May;28(5):1412-8. doi: 10.1097/00003246-200005000-00026.

  PMID: 10834688 BACKGROUND

• Djedaini K, Billiard M, Mier L, Le Bourdelles G, Brun P, Markowicz P, Estagnasie P, Coste F, Boussougant Y, Dreyfuss D. Changing heat and moisture exchangers every 48 hours rather than 24 hours does not affect their efficacy and the incidence of nosocomial pneumonia. Am J Respir Crit Care Med. 1995 Nov;152(5 Pt 1):1562-9. doi: 10.1164/ajrccm.152.5.7582295.

  PMID: 7582295 BACKGROUND

• Thomachot L, Vialet R, Viguier JM, Sidier B, Roulier P, Martin C. Efficacy of heat and moisture exchangers after changing every 48 hours rather than 24 hours. Crit Care Med. 1998 Mar;26(3):477-81. doi: 10.1097/00003246-199803000-00018.

  PMID: 9504575 BACKGROUND

• Thomachot L, Leone M, Razzouk K, Antonini F, Vialet R, Martin C. Randomized clinical trial of extended use of a hydrophobic condenser humidifier: 1 vs. 7 days. Crit Care Med. 2002 Jan;30(1):232-7. doi: 10.1097/00003246-200201000-00033.

  PMID: 11902268 BACKGROUND

• Bujang MA, Baharum N. Sample size guideline for correlation analysis. World Journal of Social Science Research . 2016;3(1):37-46

  BACKGROUND

MeSH Terms

Conditions

Critical Illness; Heart Diseases

Condition Hierarchy (Ancestors)

Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Cardiovascular Diseases

Study Officials

• Peter A Robbins, MBBS DPhil

  University of Oxford

  STUDY DIRECTOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: August 13, 2022
• First Posted: September 7, 2022
• Study Start: October 30, 2022
• Primary Completion: December 10, 2024
• Study Completion: March 1, 2025
• Last Updated: March 30, 2025

Record last verified: 2024-05

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)