Hemodynamic Effects of Apnoeic Oxygenation With High-flow Nasal Oxygen in Adults Undergoing Laryngeal Surgery (CAPOX)

Hemodynamic Effects of Apnoeic Oxygenation With High-flow Nasal Oxygen in Adults Undergoing Laryngeal Surgery - a Randomised Study

During apnoeic oxygenation there is a continuous raise in carbon dioxide with subsequent respiratory acidosis. The hypercapnia and respiratory acidosis have several dose-related effects on both the systemic and the pulmonary circulation and the heart that ultimately, if unrecognised, can result in cardiovascular collapse and fatal arrhythmias. In our knowledge, no studies have investigated the haemodynamic effects of apnoeic oxygenation with HFNO.

The general purpose of this project is to investigate haemodynamic alternations during apnoeic oxygenation with HFNO compared to mechanical ventilation in relatively healthy patients under general anaesthesia during laryngeal surgery.

Study Overview

• Status: Completed
• Conditions: Laryngeal Disease
• Intervention / Treatment: Device: Apnoeic oxygenation with high-flow nasal oxygen; Other: Mechanical ventilation

Detailed Description

This study aims to investigate and observe the circulatory effects in a patient undergoing apnoeic oxygenation with HFNO during shorter elective laryngeal surgery over time and compared to mechanical ventilation. 20 patients scheduled for elective laryngeal surgery, eligible for apnoeic oxygenation at the Karolinska University Hospital, will be recruited. If eligible, the patient will receive oral and written study information by one of the investigators well in advance of the planned surgery. After a signed consent, the subject will be enrolled and randomised to either apnoeic oxygenation with HFNO or mechanical ventilation.

Patient characteristics such as age, sex, weight, height, ASA classification, other comorbidities and airway-related parameters will be documented. A preoperative transthoracic echocardiographic examination and routine perioperative monitoring, will be performed together with a 12-lead ECG. Preoperatively, an arterial catheter will be inserted in the radial artery and an arterial blood gas, measuring PaCO2, PaO2, pH, HCO3 and blood samples of stress markers including catecholamines and other cardiac biomarkers will be collected. The FloTrac system will be connected to the arterial catheter and baseline values will be registered. A peripheral venous catheter is placed prior to anaesthesia and the patient is placed supine.

In the apnoeic oxygenation group the HFNO nasal prongs (Optiflow, Fisher & Paykel Healthcare, Auckland, New Zealand) is placed in the nostrils and used for pre-oxygenation, 100 % O2, 40 L/min during 3 min. Thereafter, anaesthesia is induced by intravenous Propofol and Remifentanil administration. Rocuronium for full neuromuscular blockade is administered and a jaw thrust is used to keep an open airway. The start of apnoea is noted, defined as 1 minute after Rocuronium administration. The airway will be kept patent throughout the procedure using a suspension laryngoscope, placed by the ENT surgeon.

During apnoea the flow of oxygen is increased to 70 L/min, 100% O2. Apnoea will be discontinued if any of the criteria SpO2 < 90%, PaCO2 >11 kPa, pH <7.15 or arrhythmias with haemodynamic effects occur. In the mechanical ventilation group pre-oxygenation is performed by a tight-fitting facemask, 100 % O2, for three minutes. After anaesthesia induction using intravenous Propofol and Remifentanil and Rocuronium for full neuromuscular blockade, tracheal intubation is performed and mechanical ventilation is started. The start of apnoea is noted. The ventilator is set to PEEP 5 cmH2O, tidal volume (TV) 7 ml/kg ideal body weight, FiO2 0.4, and the respiratory frequency adjusted to reach a PaCO2 of 5,0 -5,3 kPa. Standard perioperative monitoring will be registered (peripheral oxygen saturation, heart rate and MAP). Arterial blood gases will be collected and ECG performed repeatedly. Data from the FloTrac system will be monitored throughout the procedure. Transthoracic echocardiography will be performed regularly. Blood samples to analyse stress markers including catecholamines and cardiac biomarkers will be collected at specific timepoints.

At the end of the procedure, any neuromuscular blockade is reversed by Sugammadex. The end of apnoea is defined as reoccurrence of spontaneous breathing or start of mask ventilation. In the mechanically ventilated group, subjects are extubated when awake and responsive.

After the procedure and when fully awake, the patient is transferred to the post-operative unit. The FloTrac monitoring will be continued during the postoperative period and the TTE, ECG evaluation, arterial blood gases, stress markers including catecholamines and cardiac biomarkers will be repeated during the post-operative period. Routine postoperative monitoring will be performed for a minimum of 60 minutes.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Sweden
  • Stockholm, Sweden
    • Karolinska Universitetssjukhuset Huddinge

Participation Criteria

Eligibility Criteria

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

Description

Inclusion criteria

• Adult, ≥18 years old
• ASA 1-2
• BMI < 30
• Planned for elective laryngeal surgery

Exclusion criteria

• NYHA-class >1
• Pregnancy
• Severe gastric reflux
• Neuromuscular disease
• Any pulmonary disease
• Smokers or former smoker, last finished 6 months before inclusion
• Not capable of understanding study information and signing a written consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Apnoeic oxygenation with High-flow nasal oxygen; In the apnoeic oxygenation group the HFNO is used for pre-oxygenation,100 % O2, 40 L/min during 3 min. Thereafter, anaesthesia is induced by intravenous Propofol and Remifentanil. Rocuronium for full neuromuscular blockade is administered and a jaw thrust is used to keep an open airway. The airway will be kept patent throughout the procedure using a suspension laryngoscope, placed by the ENT surgeon. During apnoea oxygen will be increased to 70 L/min, 100% O2. Apnoea will be discontinued if any of the criteria SpO2 < 90%, PaCO2 >11 kPa, pH <7.15 or arrhythmias with haemodynamic effects occur.	Device: Apnoeic oxygenation with high-flow nasal oxygen; The subjects in the intervention group will be oxygenated with HFNO during the surgical procedure.
Active Comparator: Mechanical ventilation; In the mechanical ventilation group pre-oxygenation is performed by a tight-fitting facemask, 100 % O2, for three minutes. After anaesthesia induction and full neuromuscular blockade, tracheal intubation is performed and mechanical ventilation is started.	Other: Mechanical ventilation; Study subjects in the comparator group will be tracheally intubated and mechanically ventilated

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Significant haemodynamic effects during apnoeic oxygenation with HFNO	Significant haemodynamic effects such as significant increase in mPAP and/or new echocardiographic signs of right ventricular strain or failure compared to baseline, during and up to 2 hours after apnoeic oxygenation with HFNO or mechanical ventilation.	3 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Alterations in FloTrac derived central haemodynamic parameters	Alterations in FloTrac derived central haemodynamic parameters such as MAP, SV, SVRI and CI, during and up to 2 hours after apnoeic oxygenation with HFNO or mechanical ventilation.	3 hours
Alterations in Electrocardiogram	Alterations in electrocardiogram during and up to 2 hours after apnoeic oxygenation with HFNO or mechanical ventilation.	3 hours
Alterations in arterial carbon dioxide, oxygen and pH	Alterations in arterial carbon dioxide, oxygen and pH during and up to 2 hours after apnoeic oxygenation with HFNO or mechanical ventilation.	3 hours
Alterations in blood catecholamines and cardiac biomarkers	Alterations in blood catecholamines and cardiac biomarkers during and up to 2 hours after apnoeic oxygenation with HFNO or mechanical ventilation.	3 hours

Collaborators and Investigators

• Sponsor: Region Stockholm
• Collaborators: Karolinska Institutet
• Investigators: Principal Investigator: Malin Jonsson Fagerlund, Region Stockholm

Study record dates

Study Major Dates

• Study Start (Actual): March 25, 2024
• Primary Completion (Actual): November 26, 2024
• Study Completion (Actual): January 31, 2025

Study Registration Dates

• First Submitted: March 12, 2024
• First Submitted That Met QC Criteria: March 12, 2024
• First Posted (Actual): March 18, 2024

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: November 1, 2024

More Information

Terms related to this study

• Keywords: Pulmonary hypertension; Apnoeic oxygenation; Right ventricular function; High-flow nasal oxygen
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Respiratory Tract Diseases; Lung Diseases; Otorhinolaryngologic Diseases; Hypertension; Hypertension, Pulmonary; Laryngeal Diseases; Therapeutics; Airway Management; Resuscitation; Emergency Treatment; Respiratory Therapy; Respiration, Artificial
• Other Study ID Numbers: 2023-

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
• product manufactured in and exported from the U.S.: No