Abstract:Ketamine is believed to reduce airway and pulmonary tissue resistance. The aim of the present study was to determine the effects of ketamine on the resistive, elastic and viscoelastic/inhomogeneous mechanical properties of the respiratory system, lungs and chest wall, and to relate the mechanical data to findings from histological lung analysis in normal animals. Fifteen adult male Wistar rats were assigned randomly to two groups: control (N = 7) and ketamine (N = 8). All animals were sedated (diazepam, 5 mg, … Show more
“…Tissue stress increases at high P L , as a consequence of high V T , high R R and . The fact that C L‐dyn was higher, but C L‐stat was lower in P/U compared with that in K/M group is in agreement with the suggestion (Alves‐Neto et al. 2001) that ketamine increases lung resistances.…”
This study suggests that the breathing pattern induced by the different anaesthetic regimen may damage the pulmonary interstitium even during spontaneous breathing at physiological tidal volumes.
“…Tissue stress increases at high P L , as a consequence of high V T , high R R and . The fact that C L‐dyn was higher, but C L‐stat was lower in P/U compared with that in K/M group is in agreement with the suggestion (Alves‐Neto et al. 2001) that ketamine increases lung resistances.…”
This study suggests that the breathing pattern induced by the different anaesthetic regimen may damage the pulmonary interstitium even during spontaneous breathing at physiological tidal volumes.
“…Studies on pharmacology of ketamine indicate that it alters airway muscle movement and tranquilizes respiratory activity by reducing the release of acetylcholine in medial pontine reticular formation [38,43,44]. In rat model, ketamine has found to be doing so by increasing viscoelasticity of lung and influencing alveoli [45]. Aforementioned results demonstrate ketamine as a promising sedative for the patients with OSAS because it highly avoids respiratory events during anesthesia [46,47].…”
Section: Intravenous Anesthetic Agent: Propofol and Ketaminementioning
Since both anesthesia and sleep depress consciousness, bidirectional relationship between them has been further studied. Earlier findings have shown that they share electroencephalographic features and brain regions that are activated in both state of unconsciousness. Despite these similarities, medication-induced sedation provokes different outcome from natural sleep. Enlisting commonly used analgesic drugs, such as benzodiazepines, intravenous agents, benzodiazepine antagonists, opioids, and other adjuvants, the study is comprised of assorted case studies that are clinically applicable or comparable. Acknowledging potential of analgesic drugs on sleep disorders including sleep deprivation, narcolepsy, circadian rhythm disorder, periodic limb movement disorder, and obstructive sleep apnea, the study underscores the clinical importance of studying both fields, sleep and anesthesia. In conclusion, the aim of this review is explaining the consequences of analgesic agents or sedatives on sleep and sleep disorders.
“…Elevation of G can most prominently indicate ventilation heterogeneity due to inhomogeneous small airway constriction and/or closure ( Hantos et al, 1992 ; Lutchen et al, 1996 ). As ketamine reportedly increases the collapsibility of the lung periphery, subsequent increases in ventilation heterogeneity may explain substantial increases in G ( Alves-Neto et al, 2001 ). While the protective effects of volatile anaesthetics (including sevoflurane) against cholinergic bronchoconstriction are well-established ( Mitsuhata et al, 1994 ; Habre et al, 1997 ; Habre et al, 2001 ; Balogh et al, 2017 ), we were unable to demonstrate a protective effect of sevoflurane on bronchoconstriction in the present study.…”
Background: Respiratory parameters in experimental animals are often characterised under general anaesthesia. However, anaesthesia regimes may alter the functional and mechanical properties of the respiratory system. While most anaesthesia regimes have been shown to affect the respiratory system, the effects of general anaesthesia protocols commonly used in animal models on lung function have not been systematically compared.Methods: The present study comprised 40 male Sprague-Dawley rats divided into five groups (N = 8 in each) according to anaesthesia regime applied: intravenous (iv) Na-pentobarbital, intraperitoneal (ip) ketamine-xylazine, iv propofol-fentanyl, inhaled sevoflurane, and ip urethane. All drugs were administered at commonly used doses. End-expiratory lung volume (EELV), airway resistance (Raw) and tissue mechanics were measured in addition to arterial blood gas parameters during mechanical ventilation while maintaining positive end-expiratory pressure (PEEP) values of 0, 3, and 6 cm H2O. Respiratory mechanics were also measured during iv methacholine (MCh) challenges to assess bronchial responsiveness.Results: While PEEP influenced baseline respiratory mechanics, EELV and blood gas parameters (p < 0.001), no between-group differences were observed (p > 0.10). Conversely, significantly lower doses of MCh were required to achieve the same elevation in Raw under ketamine-xylazine anaesthesia compared to the other groups.Conclusion: In the most frequent rodent model of respiratory disorders, no differences in baseline respiratory mechanics or function were observed between commonly used anaesthesia regimes. Bronchial hyperresponsiveness in response to ketamine-xylazine anaesthesia should be considered when designing experiments using this regime. The findings of the present study indicate commonly used anaesthetic regimes allow fair comparison of respiratory mechanics in experimental animals undergoing any of the examined anaesthesia protocols.
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