Glottal Patency during Experimental Seizures in Piglets

Terndrup, Thomas E.; Kadison, Alan S.; Woo, Peak

doi:10.1203/00006450-199512000-00017

Cited by 7 publications

(8 citation statements)

References 11 publications

(16 reference statements)

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“…Dr. Terndrup and various coauthors described in the late 1980s and mid‐1990s the use of assorted chemoconvulsants, most notably subcortical PCN injection, to demonstrate physiologic changes in vital signs occurring during convulsive activity in pigs (Terndrup et al., 1993, 1994, 1995, 1999; Terndrup & Fordyce, 1995; Leaming et al., 1999). In addition, due to easy glottal access, several glottal parameters were investigated in relation to clinical events (Terndrup et al., 1995; Leaming et al., 1999). Interestingly, the cortical seizure activity was not assessed beyond its presence by a single tungsten wire electrode; therefore, the spatial and temporal variability has not been understood.…”

Section: Discussionmentioning

confidence: 99%

Swine model for translational research of invasive intracranial monitoring

et al. 2011

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Summary Focal cortical epilepsy is currently most effectively studied in humans. However, improvement in cortical monitoring and investigational device development is limited by lack of an animal model mimicking human acute focal cortical epileptiform activity under epilepsy surgery conditions. Therefore, we assessed the swine model for translational epilepsy research. Swine were used due to their cost effectiveness, convoluted cortex, and comparative anatomy similar to humans. Focal subcortical injection of benzyl-penicillin produced clinical seizures correlating with epileptiform activity demonstrating temporal and spatial progression. Swine were evaluated under 5 different anesthesia regimens. Of the 5 regimens, conditions similar to human intraoperative anesthesia, including continuous fentanyl with low dose isoflorane, was the most effective for eliciting complex, epileptiform activity after benzyl-penicillin injection. The most complex epileptiform activity (spikes, and high frequency activity) was then repeated reliably in 9 animals, utilizing 14 swine total. There were 20.1 ± 10.8 (95% CI: 11.8–28.4) epileptiform events with greater than 3.5 hertz activity occurring per animal. Average duration of each event was 46.3 ± 15.6 (95% CI: 44.0 to 48.6) seconds, ranging from 20 to 100 seconds. In conclusion, the acute swine model of focal cortical epilepsy surgery provides an animal model mimicking human surgical conditions with a large brain, gyrated cortex, and is relatively cheap among animal models. Therefore, we feel this model provides a valuable, reliable, and novel platform for translational studies of implantable hardware for intracranial monitoring.

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Section: Discussionmentioning

confidence: 99%

Swine model for translational research of invasive intracranial monitoring

et al. 2011

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“…14,15 The present study provides additional data to assist in understanding the mechanisms of upper-airway obstruction during experimental seizures. Our prior studies in intact animals used systemic chemoconvulsants, which are known to produce direct respiratory stimulation as well as seizures, complicating the respiratory interpretation of those studies.…”

Section: Discussionmentioning

confidence: 89%

“…Our prior studies in intact animals used systemic chemoconvulsants, which are known to produce direct respiratory stimulation as well as seizures, complicating the respiratory interpretation of those studies. 14,15 The cortical model of seizures in this study is more representative of the origin of epileptic discharges. The current study provides direct evidence of glottal obstruction under experimental conditions more closely related to human seizure disorders.…”

Section: Discussionmentioning

confidence: 99%

“…The procedures, anesthesia, and model used were similar to those of our prior studies of piglet seizures. 11,14,15 This protocol was approved by the Committee for the Humane Use of Animals, in accord with National Institutes of Health Guidelines for Care and Use of Animals.…”

Section: Methodsmentioning

confidence: 99%

“…15 Thus, in these pigs, despite augmentation of central respiratory drive during seizures, upper-airway obstruction at the level of the glottis occurs during systemically-induced seizures.…”

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confidence: 93%

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Glottal Patency during Experimental Cortical Seizures in Piglets

Leaming

Terndrup

Ognibene

1999

Academic Emergency Medicine

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Abstract. Objective: Systemically-induced seizures produce glottal airflow obstruction in anesthetized pigs, resulting in hypercapnia and respiratory acidosis. Cortically-induced seizures may be more representative of human seizure disorders. The purpose of this study was to describe glottal area patency (GAP) in piglets during cortically-induced seizures. Methods: Nineteen spontaneously breathing, lightly anesthetized (alphaxalone-alphadolone IV) piglets (aged 10 Ϯ 2 days) were instrumented for recording nasal airflow, subglottic pressure, and electrocorticogram. Glottal visualization was achieved supraglottically using a 1.2-mm fiberoptic scope inserted through the thyrohyoid membrane. Following baseline-control, hypoxic-rebreathing, and new baseline recordings, seizures were induced using subcortical injections of crystalline penicillin G (100,000 units/ injection). Five consecutive-breath representative epochs were digitized from baseline-control, hypoxic-rebreathing, and seizure conditions. For each breath, GAP was measured at the onset of inspiratory pressure, peak of inspiratory effort (Ip), and onset of expiration. Results: The piglets were physiologic at baseline-control and new baseline conditions, and showed expected increases in ventilation and GAP during rebreathing experiments. GAP was maximum at Ip under baseline and rebreathing conditions, but was significantly decreased and airway resistances were increased during seizure conditions (p < 0.05, ANOVA). Conclusions: Generalized seizure activity results in reduced GAP at the peak of inspiratory effort. Increased work of breathing during seizures is created by direct mechanical obstruction at the level of the larynx.

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Intrinsic muscles and distribution of the recurrent laryngeal nerve in the pig larynx

Knight

McDonald

Birchall

2004

Eur Arch Otorhinolaryngol

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To use the pig larynx in studies of laryngeal reinnervation, it is essential to have a clear understanding of its anatomy. We aimed to define the macroscopic anatomy of the intrinsic muscles and the course of the recurrent laryngeal nerve (RLN) in the pig larynx. Twelve large white pig larynges were used. Five larynges were preserved in formalin, then dissected to study the anatomy of the intrinsic muscles. Seven larynges were stained using the modified Sihler's staining technique, which results in nerves being stained dark purple while the remainder of the larynx is rendered translucent. The intrinsic muscles of the pig larynx were similar to those in the human. The RLN gives off a branch that enters the posterior cricoarytenoid muscle (PCA) on its deep surface and supplies the entire muscle, although the branching pattern of the nerve within the muscle varies considerably. These results facilitate detailed reinnervation studies in the pig laryngeal transplant model.

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Glottal Patency during Experimental Seizures in Piglets

Cited by 7 publications

References 11 publications

Swine model for translational research of invasive intracranial monitoring

Swine model for translational research of invasive intracranial monitoring

Glottal Patency during Experimental Cortical Seizures in Piglets

Intrinsic muscles and distribution of the recurrent laryngeal nerve in the pig larynx

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