https://doi.org/10.5061/dryad.3n5tb2rv6

Description of the data and file structure

Prior to general anesthesia (0) as well as immediately after recovery (R) and 1, 3, 5 and 7 days after general anesthesia videoendoscopy of the trachea was performed with sedation. The videoendoscope was passed through the ventral meatus of the nasal passages, down the trachea to the carina and the images were recorded while moving the videoendoscope orally. Screenshots of the endoscopy included the 15 cm segment of the trachea where measurements indicated location of the distal end of the endotracheal tube as well as the cuff of the endotracheal tube. These pictures were then uploaded anonymized into a PowerPoint file in randomized order for offline analysis.

All pictures were analyzed by three different evaluators (ECVAA boarded anesthetist, ECEIM boarded internist, ECVS boarded surgeon) scoring the degree of redness, hemorrhage, secretion and build-up, mucosal erosion and mucous membrane replacement (Table 1).

Anesthesia protocol and tracheal intubation

Prior to anesthesia, a complete physical exam and a CBC were performed for a baseline health status assessment.

Horses received systemic antimicrobial agents and systemic nonsteroidal anti-inflammatories (NSAIDs) based on the procedure performed.

Sedation [0.6-1 mg/kg xylazine (Xylavet®, Vetoquinol GmbH, Germany) IV], anesthesia induction [0.05 mg/kg diazepam (DiazepamAbZ® 10mg, AbZ Pharma GmbH, Germany) and 2.2 mg/kg ketamine (Narketan®, Vetoquinol GmbH, Germany) IV] and maintenance of anesthesia with isoflurane (Isofluran® CP, CP-Pharma, Germany) in oxygen were identical in all horses. Lactated Ringer’s solution was administered at a rate of 5 ml/kg/h and dobutamine (Dobutamin-ratiopharm® 250mg, ratiopharm GmbH, Germany) was given to effect to maintain a mean arterial blood pressure (MAP) above 60 mmHg during anesthesia.

Arterial blood pressure, heart rate, respiratory rate, arterial saturation via pulse oximetry, expired CO2concentration via capnography, inspired oxygen concentration and expiratory isoflurane concentration were monitored and recorded continuously with an anesthetic multi-parameter monitor (Cardiocap/5, Datex-Ohmeda GmbH, Germany).

Following the induction of anesthesia horses were orotracheally intubated in lateral recumbency using a blind technique. The head and neck were extended in a straight line and the mouth was opened using a mouth gag. A lubricated high volume, low pressure Cook silicone endotracheal tube was inserted past the arytenoid cartilages. Number of intubation attempts were recorded and horses that had a difficult intubation needing more than a single intubation attempt were excluded from further analysis to reduce the bias of injury by the intubation itself. Breath sounds and capnography confirmed correct placement. Horses with a bodyweight of 400 kg to 500 kg were intubated using a 26 mm inner diameter tube and horses with a bodyweight of 500 kg to 600 kg were intubated using a 30 mm inner diameter endotracheal tube. The endotracheal tube cuff was then inflated via the pilot balloon until a pressure of 40 cmH2O was confirmed via manometer. Pulse oximetry, capnography, and direct blood pressure measurements were continuously monitored. Airway pressures were maintained within safe clinical limits, and the 40 cmH2O endotracheal tube cuff pressure was maintained to provide effective ventilation and minimize pressure on the tracheal wall.

The horses were then positioned on a surgery table in lateral or dorsal recumbency and a pressure limited and pressure cycled large animal ventilator (Vet.-Tec. Model JAVC 2000 J.D. Medical Distributing Company Phoenix, USA) was used for mechanical ventilation. Tidal volume and respiratory rate were standardized to reduce inter-patient variability. The peak inspiratory pressure (PIP) was maintained between 25 and 30 cmH2O and the frequency was adjusted to maintain the expiratory CO2 concentration between 35 and 45 mmHg. At the end of anesthesia, the vaporizer setting was turned to zero and mechanical ventilation was stopped. Horses were ventilated by squeezing the re-breathing bag every 30 seconds until spontaneous breathing commenced. The horses were disconnected from the circuit and were placed into a padded recovery stall in lateral recumbency. Once swallowing the endotracheal tube cuff was deflated and the endotracheal tube was removed. Oxygen was insufflated through the nostrils with a flow rate of 15 L min-1 and horses were sedated with 0.1-0.2 mg/kg xylazine and assisted during recovery using head-and-tail rope support.

Complete physical exams including monitoring of respiratory rate and pattern as well as coughing and nasal discharge were performed every 6 hours for the first three days post anesthesia and then every 12 hours until discharge from the hospital.

Endoscopic Evaluation

Tracheal evaluations were performed using flexible endoscopyprior to general anesthesia (0) as well as immediately after recovery (R) and 1, 3, 5 and 7 days after general anesthesia. Lesions severity was scored on a scale from 0 (no lesions) to 4 (severe lesions). The segments assessed included a 15 cm region proximal to the carina and a 25 cm region distal to the larynx.

Access information

Other publicly accessible locations of the data:

• none

Data was derived from the following sources:

• n.a.