The role of the upper airway in contributing to respiratory responses during experimental seizures in piglets

• Published in: Pediatric research Vol. 38; no. 1; pp. 61 - 66
• Main Authors: TERNDRUP, T. E, GREGORY, M. E, FORDYCE, W. E
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.07.1995
• Subjects: Analysis of Variance; Animals; Biological and medical sciences; Electroencephalography; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Respiration - physiology; Seizures - chemically induced; Seizures - physiopathology; Swine; Trachea - physiopathology; Tracheostomy; Nervous system diseases; Pathophysiology; Upper respiratory tract; Respiratory disease; Epilepsy; Cerebral disorder; Pig; Vertebrata; Mammalia; Lung function; Weaned animal; Central nervous system disease; Complication; Ventilation; Tracheostomy; Artiodactyla; Ungulata; Comparative study
• ISSN: 0031-3998; 1530-0447
• DOI: 10.1203/00006450-199507000-00011

Recent data demonstrating stimulation of respiration during seizures are at odds with the frequent clinical finding of respiratory impairment in patients with generalized seizures. To determine the role of the upper airway in contributing to these clinical observations, a study was performed in 12 weanling piglets. An arterial catheter and epidural electrodes were placed in ketamine-anesthetized piglets. In intact piglets, all airflow was measured through a snug-fitting nasal mask whereas pressure was measured with a subglottic catheter. Tracheostomized piglets had airflow and pressure measured at the trachea. Seizures were induced with i.v. injections of pentylenetetrazol. Peak inspiratory flow resistance was calculated by averaging three epochs of five to seven consecutive breaths. Epochs of greater than 20 s in duration with a tidal volume of < 10 mL were termed apnea. Apnea was considered central when airway pressure was > -2 cm H2O and obstructive when < -10 cm H2O. After 20 min of untreated seizures, intact piglets had significant respiratory and metabolic acidosis, whereas tracheostomized piglets had significant increases in Ve and mild metabolic acidosis. Apnea and obstruction were observed frequently in intact piglets. Resistance was unchanged during seizures in tracheostomized piglets, whereas a nearly 4-fold increase in inspiratory resistance was observed in intact piglets. We conclude that upper airway patency and resistances are important determinants of respiratory responses during generalized seizures in piglets.