A Structured Approach to Extubation in Mechanically Ventilated Rats

Summary

This study proposes a structured extubation approach tailored to rat models of mechanical ventilation (MV). The approach facilitates a smooth transition from MV to spontaneous breathing while minimizing extubation-related complications. Standardization of weaning, airway management, and post-extubation care enhances the reliability and reproducibility of experimental studies.

Abstract

Mechanical ventilation (MV) is widely used in critical care but is associated with various complications that affect both short- and long-term outcomes, including ventilator-induced lung injury, ventilator-induced diaphragm dysfunction, and ventilator-associated brain injury. These are key components of post-intensive care unit syndrome (PICS). Rodent models are vital for investigating the prolonged impacts and underlying mechanisms of MV, yet standardized post-extubation models remain limited. Extubation is a critical transition step that is often inconsistently performed in existing rat models, leading to failures and complications. This study presents a four-step structured extubation approach for Sprague-Dawley rat models of MV, designed to optimize the transition from MV to spontaneous breathing while minimizing extubation-related complications. The approach involved: (1) initiating weaning by reducing propofol sedation to 50% and assessing readiness via respiratory rate, chest displacement, arterial blood gases, and reflexes; (2) preparing for extubation through airway clearance and maintenance of oxygenation; (3) executing extubation with maintained sedation and controlled tube removal; and (4) providing post-extubation care involving continuous monitoring and oxygen support. Validated through 20 successful extubations following initial failures, this model offers a valuable platform for studying the long-term effects of MV, particularly in the context of PICS. This approach is optimized for 6 h of MV and is assumed to be extendable to other strains and longer ventilation durations, although such adaptations require careful validation and monitoring to ensure reliability and animal welfare.

Introduction

Mechanical ventilation (MV) remains a cornerstone of critical care, providing essential respiratory support for acute respiratory failure and serving as a vital adjunct during anesthesia for surgical procedures¹. However, MV is associated with a range of complications, such as ventilator-induced lung injury², ventilation-induced diaphragm and expiratory muscles dysfunction^3,4,5,6, and ventilator-associated brain injury^7,8. These complic....

Protocol

The study focused on post-extubation behavioral testing and was approved by the Animal Experiments and Experimental Animal Welfare Committee of Capital Medical University (No. AEEI-2024-391). All rats aged 8 weeks (SD, male, 200-250 g) were acclimatized in the animal facility at Capital Medical University for 3 days prior to the experiment. The rat was housed under a controlled environment, including a 12-h light/dark cycle beginning at 8:00 AM, a temperature of 25 °C ± 1 °C, and humidity maintained at 50% ± 10 %. Food and water were provided ad libitum. All procedures involving anesthesia, suctioning, and blood handling were performed wit....

Results

This structured extubation approach was developed on four failed extubations and 20 subsequent successful extubations. In the first four attempts, extubation was performed based on the experience or individual judgment. Reasons for the four rats' failed extubation included agitation during extubation(n = 2), post-extubation respiratory insufficiency (n = 1), and airway obstruction by secretions (n = 1). These failures highlighted that optimal sedation, a clear airway, and sufficient oxyge.......

Discussion

In this study, a structured APEC extubation approach was established for a rat model of MV, inspired by the first four failed extubations and the underlying causes. All 20 rats extubated using this approach succeeded and completed subsequent behavioral testing within the following three days. The approach, consisting of four key steps -- Approaching weaning, Preparing extubation, Executing extubation, and Post-extubation care -- was designed to ensure a smooth transition from mechanical to spontaneous breathing while min.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
16G Endotracheal Tube	NJKEWBIO	NA	Endotracheal tube
Blood Gas Analyzer	Epocal Inc	EPOC reader	Monitor blood gases
Intravenous Catheter	Introcan Safety	4254074B	Indwelled in the arteries and veins
Micro-syringe Pump	SLGO Medical Technology	CP-1000	Infusion of drugs
Pet Oxygen Concentrator	Beijing zhongshidichuang Science and technology development Co.,Ltd	ZS-MV	Supply of oxygen
Small Animal Heating Blanket	Beijing zhongshidichuang Science and technology development Co.,Ltd	ZS-T	Maintain temperature
Small Animal Ventilator	NJKEWBIO	KW-100	Provide breathing