INDICATIONS, MANAGEMENT AND OUTCOME OF LONG TERM POSITIVE PRESSURE VENTILATION IN DOGS AND CATS: 152 CASES (1991–2001)

Abstract

Objective: To retrospectively evaluate the indications, management and outcome of 152 cases of long‐term positive pressure ventilation (PPV).Methods: Medical records of patients maintained on PPV for 24 hours or longer, from 1991 to 2001 were reviewed. All cases were categorized into 3 groups according to the reason they required PPV: animals with pulmonary parenchymal disease that were not adequately oxygenating (1), animals with neuromuscular or large airway disease that were not adequately ventilating (2), or animals with both inadequate oxygenation and ventilation (3).Results: A total of 152 ventilator episodes were identified represented by 124 dogs and 24 cats. The median duration of ventilation was 49 hours (range 24–356 hours). Overall, 41.4% of cases were weaned, and 27% of cases survived to discharge. There were 78 cases with inadequate oxygenation (Group 1), of which 37.2% were weaned and 20.5% survived to discharge. There were 62 cases with inadequate ventilation (Group 2), of which 50% were weaned and 38.7% survived to discharge. In Group 3, 10 cases were identified; 25% were weaned and 8.3% survived to discharge. Arterial blood gases were collected in 61.2% of cases prior to PPV. Venous blood gases were collected in 10.5% of cases and an SpO2 was recorded on 2% of cases. In 26.3% of cases, no blood gas or SpO2 measurements were performed prior to PPV. The mean PaCO2 prior to PPV was 46.9±15.5 mmHg in Group 1, 72.6±26.9 mmHg in Group 2, and 64.3±14.1 mmHg in Group 3. In Groups 1, 2 and 3, the mean PaO2/FIO2 ratio was 101.7±67.6, 262.6±210.9 and 115.7±75.9, respectively. Pentobarbital, with or without diazepam, was the most common induction (28.9%) and maintenance (61.8%) agent utilized. Most cases (91.4%) were initially stabilized with volume or pressure control. Of the animals weaned from PPV, synchronous intermittent mandatory ventilation was used in 46% of cases and continuous positive airway pressure was used in 22.2%. Complications included pneumothorax (6.6%), oral ulceration (5.9%), and corneal ulceration (3.9%).Conclusion: Long‐term PPV can be both practical and successful in veterinary medicine. Patients that require PPV due to pulmonary parenchymal disease had lower weaning and survival rates than those without.