1
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Kılınç Z, Ayyıldız EA, Kaya E, Sahin AS. The Effect of Oxygenation on Mortality in Patients With Head Injury. Cureus 2023; 15:e34385. [PMID: 36874741 PMCID: PMC9976649 DOI: 10.7759/cureus.34385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2023] [Indexed: 02/03/2023] Open
Abstract
Introduction In this study, we planned to investigate the effect of hyperoxygenation on mortality and morbidity in patients with head trauma who were followed and treated in the intensive care unit (ICU). Methods Head trauma cases (n = 119) that were followed in the mixed ICU of a 50-bed tertiary care center in Istanbul between January 2018 and December 2019 were retrospectively analyzed for the negative effects of hyperoxia. Age, gender, height/weight, additional diseases, medications used, ICU indication, Glasgow Coma Scale score recorded during ICU follow-up, Acute Physiology and Chronic Health Evaluation (APACHE) II score, length of hospital/ICU stay, the presence of complications, number of reoperations, length of intubation, and the patient's discharge or death status were evaluated. The patients were divided into three groups according to the highest partial pressure of oxygen (PaO2) value (200 mmHg) in the arterial blood gas (ABG) taken on the first day of admission to the ICU, and ABGs on the day of ICU admission and discharge were compared. Results In comparison, the first arterial oxygen saturation and initial PaO2 mean values were found to be statistically significantly different. There was a statistically significant difference in mortality and reoperation rates between groups. The mortality was higher in groups 2 and 3, and the rate of reoperation was higher in group 1. Conclusion In our study, mortality was found to be high in groups 2 and 3, which we considered hyperoxic. In this study, we tried to draw attention to the negative effects of common and easily administered oxygen therapy on mortality and morbidity in ICU patients.
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Affiliation(s)
- Zehra Kılınç
- Anesthesiology and Reanimation, Kanuni Sultan Süleyman Training and Research Hospital, Istanbul, TUR
| | - Elif Aybike Ayyıldız
- Anesthesiology and Reanimation, Kanuni Sultan Süleyman Training and Research Hospital, Istanbul, TUR
| | - Ebru Kaya
- Intensive Care Unit, Kanuni Sultan Süleyman Training and Research Hospital, Istanbul, TUR
| | - Ayca Sultan Sahin
- Anesthesiology and Reanimation, Kanuni Sultan Süleyman Training and Research Hospital, Istanbul, TUR
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2
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Dean JB, Stavitzski NM. The O2-sensitive brain stem, hyperoxic hyperventilation, and CNS oxygen toxicity. Front Physiol 2022; 13:921470. [PMID: 35957982 PMCID: PMC9360621 DOI: 10.3389/fphys.2022.921470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Central nervous system oxygen toxicity (CNS-OT) is a complex disorder that presents, initially, as a sequence of cardio-respiratory abnormalities and nonconvulsive signs and symptoms (S/Sx) of brain stem origin that culminate in generalized seizures, loss of consciousness, and postictal cardiogenic pulmonary edema. The risk of CNS-OT and its antecedent “early toxic indications” are what limits the use of hyperbaric oxygen (HBO2) in hyperbaric and undersea medicine. The purpose of this review is to illustrate, based on animal research, how the temporal pattern of abnormal brain stem responses that precedes an “oxtox hit” provides researchers a window into the early neurological events underlying seizure genesis. Specifically, we focus on the phenomenon of hyperoxic hyperventilation, and the medullary neurons presumed to contribute in large part to this paradoxical respiratory response; neurons in the caudal Solitary complex (cSC) of the dorsomedial medulla, including putative CO2 chemoreceptor neurons. The electrophysiological and redox properties of O2-/CO2-sensitive cSC neurons identified in rat brain slice experiments are summarized. Additionally, evidence is summarized that supports the working hypothesis that seizure genesis originates in subcortical areas and involves cardio-respiratory centers and cranial nerve nuclei in the hind brain (brainstem and cerebellum) based on, respectively, the complex temporal pattern of abnormal cardio-respiratory responses and various nonconvulsive S/Sx that precede seizures during exposure to HBO2.
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3
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Zhang Y, You B, Chen Y, Yang J, Xie C, Huang G, Li R, Hu P. Effect of Transcriptional Regulatory Factor FoxO3a on Central Nervous System Oxygen Toxicity. Front Physiol 2021; 11:596326. [PMID: 33391015 PMCID: PMC7775677 DOI: 10.3389/fphys.2020.596326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/24/2020] [Indexed: 11/23/2022] Open
Abstract
Central nervous system (CNS) oxygen toxicity (CNS-OT) is a toxic reaction that appears after the inhalation of gas at an excessive oxygen partial pressure during underwater operation or hyperbaric oxygen (HBO) treatment. The mechanism of CNS-OT has not been clearly characterized. Though it has been attributed to the excessive oxidative stress induced by HBO, evidences against this hypothesis have been reported. Here we find that Forkhead box protein O3 (FoxO3a) is important for CNS-OT protection. FoxO3a knock-out (KO) mice had a shorter latency to develop convulsions and greater number of seizures within a certain period of time. The acute lung injury (ALI) induced by CNS-OT was also more severe in FoxO3a KO mice. Further analysis reveals a significant decrease in the activity of catalase (CAT), an antioxidant enzyme and a significant increase in the content of malondialdehyde (MDA), an oxidative product, in brain tissues of FoxO3a KO mice. Short-time HBO exposure could increase FoxO3a expression level and trigger its nuclear translocation. The level of nuclear localized FoxO3a peaked at 8 h after exposure. Our results demonstrate that the activity of FoxO3a is highly sensitive to HBO exposure and FoxO3a plays important roles in protecting CNS-OT. Further mechanic analysis reveals that FoxO3a protects CNS-OT via activating antioxidative signaling pathway.
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Affiliation(s)
- Yanan Zhang
- Department of Diving and Hyperbaric Medicine, Naval Special Medical Center, Navy Medical University, Shanghai, China
| | - Benming You
- Department of Pharmacy, Changhai Hospital, Navy Medical University, Shanghai, China
| | - Yuliang Chen
- Department of Nautical and Aviation Medicine Center, The Sixth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Junlin Yang
- Xinhua Hospital, Shangahai Jiao Tong University, Shanghai, China
| | - Chengwei Xie
- Department of Diving and Hyperbaric Medicine, Naval Special Medical Center, Navy Medical University, Shanghai, China
| | - Guoyang Huang
- Department of Diving and Hyperbaric Medicine, Naval Special Medical Center, Navy Medical University, Shanghai, China
| | - Runping Li
- Department of Diving and Hyperbaric Medicine, Naval Special Medical Center, Navy Medical University, Shanghai, China
| | - Ping Hu
- State Key Laboratory of Cell Biology, Center of Excellence in Molecular and Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.,Xinhua Hospital, Shangahai Jiao Tong University, Shanghai, China.,Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai, China
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4
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Platonova TF, Zhilyaev SY, Alekseeva OS, Nikitina ER, Demchenko IT. Blockade of Brain Adrenoreceptors
Delays Seizure Development during Hyperbaric Oxygen Breathing. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s0022093020050051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Ciarlone GE, Hinojo CM, Stavitzski NM, Dean JB. CNS function and dysfunction during exposure to hyperbaric oxygen in operational and clinical settings. Redox Biol 2019; 27:101159. [PMID: 30902504 PMCID: PMC6859559 DOI: 10.1016/j.redox.2019.101159] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/20/2019] [Accepted: 03/01/2019] [Indexed: 12/26/2022] Open
Abstract
Hyperbaric oxygen (HBO2) is breathed during hyperbaric oxygen therapy and during certain undersea pursuits in diving and submarine operations. What limits exposure to HBO2 in these situations is the acute onset of central nervous system oxygen toxicity (CNS-OT) following a latent period of safe oxygen breathing. CNS-OT presents as various non-convulsive signs and symptoms, many of which appear to be of brainstem origin involving cranial nerve nuclei and autonomic and cardiorespiratory centers, which ultimately spread to higher cortical centers and terminate as generalized tonic-clonic seizures. The initial safe latent period makes the use of HBO2 practical in hyperbaric and undersea medicine; however, the latent period is highly variable between individuals and within the same individual on different days, making it difficult to predict onset of toxic indications. Consequently, currently accepted guidelines for safe HBO2 exposure are highly conservative. This review examines the disorder of CNS-OT and summarizes current ideas on its underlying pathophysiology, including specific areas of the CNS and fundamental neural and redox signaling mechanisms that are thought to be involved in seizure genesis and propagation. In addition, conditions that accelerate the onset of seizures are discussed, as are current mitigation strategies under investigation for neuroprotection against redox stress while breathing HBO2 that extend the latent period, thus enabling safer and longer exposures for diving and medical therapies.
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Affiliation(s)
- Geoffrey E Ciarlone
- Undersea Medicine Department, Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD, USA
| | - Christopher M Hinojo
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Nicole M Stavitzski
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Jay B Dean
- Department of Molecular Pharmacology and Physiology, Hyperbaric Biomedical Research Laboratory, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
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6
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Demchenko IT, Zhilyaev SY, Alekseeva OS, Krivchenko AI, Piantadosi CA, Gasier HG. Increased Antiseizure Effectiveness with Tiagabine Combined with Sodium Channel Antagonists in Mice Exposed to Hyperbaric Oxygen. Neurotox Res 2019; 36:788-795. [PMID: 31148118 DOI: 10.1007/s12640-019-00063-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/24/2019] [Accepted: 05/09/2019] [Indexed: 10/26/2022]
Abstract
Hyperbaric oxygen (HBO2) is acutely toxic to the central nervous system, culminating in EEG spikes and tonic-clonic convulsions. GABA enhancers and sodium channel antagonists improve seizure latencies in HBO2 when administered individually, while combining antiepileptic drugs from different functional classes can provide greater seizure latency. We examined the combined effectiveness of GABA enhancers (tiagabine and gabapentin) with sodium channel antagonists (carbamazepine and lamotrigine) in delaying HBO2-induced seizures. A series of experiments in C57BL/6 mice exposed to 100% oxygen at 5 atmospheres absolute (ATA) were performed. We predicted equally effective doses from individual drug-dose response curves, and the combinations of tiagabine + carbamazepine or lamotrigine were tested to determine the maximally effective combined doses to be used in subsequent experiments designed to identify the type of pharmacodynamic interaction for three fixed-ratio combinations (1:3, 1:1, and 3:1) using isobolographic analysis. For both combinations, the maximally effective combined doses increased seizure latency over controls > 5-fold and were determined to interact synergistically for fixed ratios 1:1 and 3:1, additive for 1:3. These results led us to explore whether the benefits of these drug combinations could be extended to the lungs, since a centrally mediated mechanism is believed to mediate hyperoxic-induced cardiogenic lung injury. Indeed, both combinations attenuated bronchoalveolar lavage protein content by ~ 50%. Combining tiagabine with carbamazepine or lamotrigine not only affords greater antiseizure protection in HBO2 but also allows for lower doses to be used, minimizing side effects, and attenuating acute lung injury.
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Affiliation(s)
- Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, USA.,Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Sergei Yu Zhilyaev
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Olga S Alekseeva
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander I Krivchenko
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Claude A Piantadosi
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, NC, USA.,Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.,Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Heath G Gasier
- Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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7
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Xie CW, Wang ZZ, Zhang YN, Chen YL, Li RP, Zhang JD. Effect of Interaction between Adenosine and Nitric Oxide on Central Nervous System Oxygen Toxicity. Neurotox Res 2019; 36:193-203. [PMID: 30927242 DOI: 10.1007/s12640-019-00025-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 11/26/2022]
Abstract
The metabolism of adenosine (ADO) and nitric oxide (NO) in brain tissues is closely associated with the change of oxygen content. They have contrary effects in the onset of hyperbaric oxygen (HBO)-induced central nervous system oxygen toxicity (CNS OT): ADO can suppress the onset, while NO promotes it. We adopted the ADO-augmenting measure and NO-inhibiting measure in this study and found the combined use had a far superior preventive and therapeutic effect in protecting against CNS OT compared with the use of either measure alone. So we hypothesized that there is an interaction between ADO and NO which has an important impact on the onset of CNS OT. On this basis, we administered ADO-augmenting or ADO-inhibiting drugs to rats. After exposure to HBO, the onset of CNS OT was evaluated, followed by the measurement of NO content in brain tissues. In another experiment, rats were administered NO-augmenting or NO-inhibiting drugs. After exposure to HBO, the onset of CNS OT was evaluated, followed by measurement of the activities of ADO metabolism-related enzymes in brain tissues. The results showed that, following ADO augmentation, the content of NO and its metabolite was significantly reduced, and the onset of CNS OT significantly improved. After ADO inhibition, just the opposite was observed. NO promotion resulted in a decrease in the activity of ADO-producing enzyme, an increase in the activity of ADO-decomposing enzyme, and an aggravation in CNS OT. The above results were all reversed after an inhibition in NO content. Studies have shown that exposure to HBO has a significant impact on the content of ADO and NO in brain tissues as well as their biological effects, and ADO and NO might have an intense interaction, which might generate an important effect on the onset of CNS OT. The prophylaxis and treatment effects of CNS OT can be greatly enhanced by augmenting ADO and inhibiting NO.
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Affiliation(s)
- Cheng-Wei Xie
- Department of Diving Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, 200433, China
| | - Zhong-Zhuang Wang
- Department of Pharmacy, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Ya-Nan Zhang
- Department of Diving Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, 200433, China
| | - Yu-Liang Chen
- Nautical and Aviation Medicine Center, Navy General Hospital of PLA, Beijing, 10048, China
| | - Run-Ping Li
- Department of Diving Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, 200433, China.
| | - Jun-Dong Zhang
- Tenth People's Hospital of Tongji University, Shanghai, 200072, China.
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8
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Gasier HG, Demchenko IT, Zhilyaev SY, Moskvin AN, Krivchenko AI, Piantadosi CA. Adrenoceptor blockade modifies regional cerebral blood flow responses to hyperbaric hyperoxia: Protection against CNS oxygen toxicity. J Appl Physiol (1985) 2018; 125:1296-1304. [PMID: 30024340 DOI: 10.1152/japplphysiol.00540.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exposure to extreme-hyperbaric oxygen (HBO2), > 5-6 atmospheres absolute (ATA), produces baroreflex impairment, sympathetic hyperactivation, hypertension, tachycardia, and cerebral hyperemia, known as Phase II, culminating in seizures. We hypothesized that attenuation of the effects of high sympathetic outflow would preserve regional cerebral blood flow (rCBF) and protect against HBO2-induced seizures. To explore this possibility, we tested four adrenoceptor antagonists in conscious and anesthetized rats exposed to HBO2 at 5 and 6 ATA, respectively: phentolamine (nonselective α1 and 2), prazosin (selective α1), propranolol (nonselective β1 and 2) and atenolol (selective β1). In conscious rats, 4 drug-doses were administered to rats prior to HBO2 exposures, and seizure latencies were recorded. Drug-doses that provided similar protection against seizures were administered before HBO2 exposures in anesthetized rats to determine the effects of adrenoceptor blockade on mean arterial pressure, heart rate, rCBF and EEG spikes. All four drugs modified cardiovascular and rCBF responses in HBO2 that aligned with epileptiform discharges, but only phentolamine and propranolol effectively increased EEG spike latencies by ~20 and 36 min, respectively. When phentolamine and propranolol were delivered during HBO2 at the onset of phase II, only propranolol led to sustained reductions in heart rate and rCBF, preventing the appearance of epileptiform discharges. The enhanced effectiveness of propranolol may extend beyond β-adrenoceptor blockade, i.e. membrane stability and reduced metabolic activity. These results indicate that adrenoceptor drug pre-treatment will minimize the effects of excessive sympathetic outflow on rCBF and extend HBO2 exposure time.
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Affiliation(s)
- Heath G Gasier
- Department of Military & Emergency Medicine, Uniformed Services University of the Health Sciences, United States
| | - Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University, United States
| | - Sergei Yu Zhilyaev
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander N Moskvin
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander I Krivchenko
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Claude A Piantadosi
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University, United States
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9
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Demchenko IT, Zhilyaev SY, Moskvin AN, Krivchenko AI, Piantadosi CA, Allen BW. Antiepileptic drugs prevent seizures in hyperbaric oxygen: A novel model of epileptiform activity. Brain Res 2017; 1657:347-354. [DOI: 10.1016/j.brainres.2016.12.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/29/2016] [Accepted: 12/31/2016] [Indexed: 11/25/2022]
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10
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Freiberger JJ, Derrick BJ, Natoli MJ, Akushevich I, Schinazi EA, Parker C, Stolp BW, Bennett PB, Vann RD, Dunworth SAS, Moon RE. Assessment of the interaction of hyperbaric N2, CO2, and O2 on psychomotor performance in divers. J Appl Physiol (1985) 2016; 121:953-964. [PMID: 27633739 DOI: 10.1152/japplphysiol.00534.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022] Open
Abstract
Diving narcosis results from the complex interaction of gases, activities, and environmental conditions. We hypothesized that these interactions could be separated into their component parts. Where previous studies have tested single cognitive tasks sequentially, we varied inspired partial pressures of CO2, N2, and O2 in immersed, exercising subjects while assessing multitasking performance with the Multi-Attribute Task Battery II (MATB-II) flight simulator. Cognitive performance was tested under 20 conditions of gas partial pressure and exercise in 42 male subjects meeting U.S. Navy age and fitness profiles. Inspired nitrogen (N2) and oxygen (O2) partial pressures were 0, 4.5, and 5.6 ATA and 0.21, 1.0, and 1.22 ATA, respectively, at rest and during 100-W immersed exercise with and without 0.075-ATA CO2 Linear regression modeled the association of gas partial pressure with task performance while controlling for exercise, hypercapnic ventilatory response, dive training, video game frequency, and age. Subjects served as their own controls. Impairment of memory, attention, and planning, but not motor tasks, was associated with N2 partial pressures >4.5 ATA. Sea level O2 at 0.925 ATA partially rescued motor and memory reaction time impaired by 0.075-ATA CO2; however, at hyperbaric pressures an unexpectedly strong interaction between CO2, N2, and exercise caused incapacitating narcosis with amnesia, which was augmented by O2 Perception of narcosis was not correlated with actual scores. The relative contributions of factors associated with diving narcosis will be useful to predict the effects of gas mixtures and exercise conditions on the cognitive performance of divers. The O2 effects are consistent with O2 narcosis or enhanced O2 toxicity.
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Affiliation(s)
- J J Freiberger
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - B J Derrick
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - M J Natoli
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - I Akushevich
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - E A Schinazi
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - C Parker
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - B W Stolp
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - P B Bennett
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - R D Vann
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - S A S Dunworth
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - R E Moon
- Duke Center for Hyperbaric Medicine and Environmental Physiology and Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
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11
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Hassanipour M, Shirzadian A, Boojar MMA, Abkhoo A, Abkhoo A, Delazar S, Amiri S, Rahimi N, Ostadhadi S, Dehpour AR. Possible involvement of nitrergic and opioidergic systems in the modulatory effect of acute chloroquine treatment on pentylenetetrazol induced convulsions in mice. Brain Res Bull 2016; 121:124-30. [DOI: 10.1016/j.brainresbull.2015.11.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/25/2015] [Accepted: 11/26/2015] [Indexed: 10/22/2022]
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12
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Hafner S, Beloncle F, Koch A, Radermacher P, Asfar P. Hyperoxia in intensive care, emergency, and peri-operative medicine: Dr. Jekyll or Mr. Hyde? A 2015 update. Ann Intensive Care 2015; 5:42. [PMID: 26585328 PMCID: PMC4653126 DOI: 10.1186/s13613-015-0084-6] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/02/2015] [Indexed: 12/22/2022] Open
Abstract
This review summarizes the (patho)-physiological effects of ventilation with high FiO2 (0.8–1.0), with a special focus on the most recent clinical evidence on its use for the management of circulatory shock and during medical emergencies. Hyperoxia is a cornerstone of the acute management of circulatory shock, a concept which is based on compelling experimental evidence that compensating the imbalance between O2 supply and requirements (i.e., the oxygen dept) is crucial for survival, at least after trauma. On the other hand, “oxygen toxicity” due to the increased formation of reactive oxygen species limits its use, because it may cause serious deleterious side effects, especially in conditions of ischemia/reperfusion. While these effects are particularly pronounced during long-term administration, i.e., beyond 12–24 h, several retrospective studies suggest that even hyperoxemia of shorter duration is also associated with increased mortality and morbidity. In fact, albeit the clinical evidence from prospective studies is surprisingly scarce, a recent meta-analysis suggests that hyperoxia is associated with increased mortality at least in patients after cardiac arrest, stroke, and traumatic brain injury. Most of these data, however, originate from heterogenous, observational studies with inconsistent results, and therefore, there is a need for the results from the large scale, randomized, controlled clinical trials on the use of hyperoxia, which can be anticipated within the next 2–3 years. Consequently, until then, “conservative” O2 therapy, i.e., targeting an arterial hemoglobin O2 saturation of 88–95 % as suggested by the guidelines of the ARDS Network and the Surviving Sepsis Campaign, represents the treatment of choice to avoid exposure to both hypoxemia and excess hyperoxemia.
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Affiliation(s)
- Sebastian Hafner
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Helmholtzstrasse 8-1, 89081, Ulm, Germany. .,Klinik für Anästhesiologie, Universitätsklinikum Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany.
| | - François Beloncle
- Département de Réanimation Médicale et de Médecine Hyperbare, Centre Hospitalier Universitaire, 4 rue Larrey, Cedex 9, 49933, Angers, France. .,Laboratoire de Biologie Neurovasculaire et Mitochondriale Intégrée, CNRS UMR 6214-INSERM U1083, Université Angers, PRES L'UNAM, Nantes, France.
| | - Andreas Koch
- Sektion Maritime Medizin, Institut für Experimentelle Medizin, Christian-Albrechts-Universität, 24118, Kiel, Germany. .,Schifffahrtmedizinisches Institut der Marine, 24119, Kronshagen, Germany.
| | - Peter Radermacher
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Helmholtzstrasse 8-1, 89081, Ulm, Germany.
| | - Pierre Asfar
- Département de Réanimation Médicale et de Médecine Hyperbare, Centre Hospitalier Universitaire, 4 rue Larrey, Cedex 9, 49933, Angers, France. .,Laboratoire de Biologie Neurovasculaire et Mitochondriale Intégrée, CNRS UMR 6214-INSERM U1083, Université Angers, PRES L'UNAM, Nantes, France.
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13
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Gasier HG, Demchenko IT, Allen BW, Piantadosi CA. Effects of striatal nitric oxide production on regional cerebral blood flow and seizure development in rats exposed to extreme hyperoxia. J Appl Physiol (1985) 2015; 119:1282-8. [PMID: 26338456 DOI: 10.1152/japplphysiol.00432.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/31/2015] [Indexed: 02/04/2023] Open
Abstract
The endogenous vasodilator and signaling molecule nitric oxide has been implicated in cerebral hyperemia, sympathoexcitation, and seizures induced by hyperbaric oxygen (HBO2) at or above 3 atmospheres absolute (ATA). It is unknown whether these events in the onset of central nervous system oxygen toxicity originate within specific brain structures and whether blood flow is diverted to the brain from peripheral organs with high basal flow, such as the kidney. To explore these questions, total and regional cerebral blood flow (CBF) were measured in brain structures of the central autonomic network in anesthetized rats in HBO2 at 6 ATA. Electroencephalogram (EEG) recordings, cardiovascular hemodynamics, and renal blood flow (RBF) were also monitored. As expected, mean arterial blood pressure and total and regional CBF increased preceding EEG spikes while RBF was unaltered. Of the brain structures examined, the earliest rise in CBF occurred in the striatum, suggesting increased neuronal activation. Continuous unilateral or bilateral striatal infusion of the nitric oxide synthase inhibitor N(ω)-nitro-L-arginine methyl ester attenuated CBF responses in that structure, but global EEG discharges persisted and did not differ from controls. Our novel findings indicate that: 1) cerebral hyperemia in extreme HBO2 in rats does not occur at the expense of renal perfusion, highlighting the remarkable autoregulatory capability of the kidney, and 2) in spite of a sentinel increase in striatal blood flow, additional brain structure(s) likely govern the pathogenesis of HBO2-induced seizures because EEG discharge latency was unchanged by local blockade of striatal nitric oxide production and concomitant hyperemia.
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Affiliation(s)
- Heath G Gasier
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina; and
| | - Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina; and
| | - Barry W Allen
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina; and
| | - Claude A Piantadosi
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina; and Department of Medicine, Duke University Medical Center, Durham, North Carolina
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Eynan M, Mullokandov M, Krinsky N, Biram A, Arieli Y. Alteration of blood glucose levels in the rat following exposure to hyperbaric oxygen. J Appl Physiol (1985) 2015; 119:463-7. [PMID: 26183474 DOI: 10.1152/japplphysiol.00154.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/15/2015] [Indexed: 01/12/2023] Open
Abstract
Findings regarding blood glucose level (BGL) on exposure to hyperbaric oxygen (HBO) are contradictory. We investigated the influence of HBO on BGL, and of BGL on latency to central nervous system oxygen toxicity (CNS-OT). The study was conducted on five groups of rats: Group 1, exposure to oxygen at 2.5 atmospheres absolute (ATA), 90 min/day for 7 days; Group 2, exposure to oxygen once a week from 2 to 6 ATA in increments of 1 ATA/wk, for a period of time calculated as 60% of the latency to CNS-OT (no convulsions); Group 3, exposure to 6 ATA breathing a gas mixture with a pO2 of 0.21; Group 4, received 10 U/kg insulin to induce hypoglycemia before exposure to HBO; Group 5, received 33% glucose to induce hyperglycemia before exposure to HBO. Blood samples were drawn before and after exposures for measurement of BGL. No change was observed in BGL after exposure to oxygen at 2.5 ATA, 90 min/day for 7 days. BGL was significantly elevated after exposure to oxygen at 6 ATA until the appearance of convulsions, and following exposure to 4, 5, and 6 ATA without convulsions (P < 0.01). No change was observed in BGL after exposure to 6 ATA breathing a gas mixture with a pO2 of 0.21. Hypoglycemia shortened latency to CNS oxygen toxicity, whereas hyperglycemia had no effect. Our results demonstrate an influence of HBO exposure on elevation of BGL, starting at 4 ATA. This implies that BGL may serve as a marker for the generation of CNS-OT.
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Affiliation(s)
- Mirit Eynan
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Michael Mullokandov
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Nitzan Krinsky
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Adi Biram
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
| | - Yehuda Arieli
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Haifa, Israel
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Demchenko IT, Gasier HG, Zhilyaev SY, Moskvin AN, Krivchenko AI, Piantadosi CA, Allen BW. Baroreceptor afferents modulate brain excitation and influence susceptibility to toxic effects of hyperbaric oxygen. J Appl Physiol (1985) 2014; 117:525-34. [PMID: 24994889 DOI: 10.1152/japplphysiol.00435.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unexplained adjustments in baroreflex sensitivity occur in conjunction with exposures to potentially toxic levels of hyperbaric oxygen. To investigate this, we monitored central nervous system, autonomic and cardiovascular responses in conscious and anesthetized rats exposed to hyperbaric oxygen at 5 and 6 atmospheres absolute, respectively. We observed two contrasting phases associated with time-dependent alterations in the functional state of the arterial baroreflex. The first phase, which conferred protection against potentially neurotoxic doses of oxygen, was concurrent with an increase in baroreflex sensitivity and included decreases in cerebral blood flow, heart rate, cardiac output, and sympathetic drive. The second phase was characterized by baroreflex impairment, cerebral hyperemia, spiking on the electroencephalogram, increased sympathetic drive, parasympatholysis, and pulmonary injury. Complete arterial baroreceptor deafferentation abolished the initial protective response, whereas electrical stimulation of intact arterial baroreceptor afferents prolonged it. We concluded that increased afferent traffic attributable to arterial baroreflex activation delays the development of excessive central excitation and seizures. Baroreflex inactivation or impairment removes this protection, and seizures may follow. Finally, electrical stimulation of intact baroreceptor afferents extends the normal delay in seizure development. These findings reveal that the autonomic nervous system is a powerful determinant of susceptibility to sympathetic hyperactivation and seizures in hyperbaric oxygen and the ensuing neurogenic pulmonary injury.
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Affiliation(s)
- Ivan T Demchenko
- Center for Hyperbaric Medicine and Environmental Physiology, and Departments of Anesthesiology and Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Heath G Gasier
- Center for Hyperbaric Medicine and Environmental Physiology, and Departments of Anesthesiology and
| | - Sergei Yu Zhilyaev
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander N Moskvin
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander I Krivchenko
- Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Claude A Piantadosi
- Center for Hyperbaric Medicine and Environmental Physiology, and Departments of Anesthesiology and Medicine, Duke University Medical Center, Durham, North Carolina
| | - Barry W Allen
- Center for Hyperbaric Medicine and Environmental Physiology, and Departments of Anesthesiology and
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Eynan M, Krinsky N, Biram A, Arieli Y, Arieli R. A comparison of factors involved in the development of central nervous system and pulmonary oxygen toxicity in the rat. Brain Res 2014; 1574:77-83. [PMID: 24928619 DOI: 10.1016/j.brainres.2014.05.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 05/09/2014] [Accepted: 05/30/2014] [Indexed: 10/25/2022]
Abstract
Central nervous system oxygen toxicity (CNS-OT) can occur in humans at pressures above 2atmospheres absolute (ATA), and above 4.5ATA in the rat. Pulmonary oxygen toxicity appears at pressures above 0.5ATA. We hypothesized that exposure to mild HBO following extreme exposure might provide protection against CNS, but not pulmonary oxygen toxicity. We measured the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX), and nitrotyrosine and nNOS levels in the brain and lung in the following groups: (1) Sham rats, no pressure exposure (SHAM); (2) Exposure to 6ATA oxygen for 60% of latency to CNS-OT (60%LT); (3) Exposure to 6ATA for 60% of latency to CNS-OT, followed by 20min at 2.5ATA for recovery (REC); (4) Exposure to 6ATA for 60% of latency to CNS-OT, followed by 20min at 2.5ATA oxygen and a subsequent increase in pressure to 6ATA until the appearance of convulsions (CONV); (5) Control rats exposed to 6ATA until the appearance of convulsions (C). SOD and CAT activity were reduced in both brain and lung in the REC group. GPX activity was reduced in the hippocampus in the REC group, but not in the cortex or the lung. nNOS levels were reduced in the hippocampus in the REC group. Contrary to our hypothesis, no difference was observed between the brain and the lung for the factors investigated. We suggest that at 2.5ATA and above, CNS and pulmonary oxygen toxicity may share similar mechanisms.
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Affiliation(s)
- Mirit Eynan
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Box 22, Rambam Health Care Campus, P.O. Box 9602, 3109601 Haifa, Israel.
| | - Nitzan Krinsky
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Box 22, Rambam Health Care Campus, P.O. Box 9602, 3109601 Haifa, Israel.
| | - Adi Biram
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Box 22, Rambam Health Care Campus, P.O. Box 9602, 3109601 Haifa, Israel.
| | - Yehuda Arieli
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Box 22, Rambam Health Care Campus, P.O. Box 9602, 3109601 Haifa, Israel.
| | - Ran Arieli
- Israel Naval Medical Institute, Israel Defense Forces Medical Corps, Box 22, Rambam Health Care Campus, P.O. Box 9602, 3109601 Haifa, Israel.
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Mahon RT, Hall A, Bodo M, Auker C. The intravenous perfluorocarbon emulsion Oxycyte does not increase hyperbaric oxygen-related seizures in a non-sedated swine model. Eur J Appl Physiol 2013; 113:2795-802. [PMID: 24062008 DOI: 10.1007/s00421-013-2720-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 08/27/2013] [Indexed: 11/30/2022]
Abstract
PURPOSE Standard treatment for decompression sickness (DCS) is recompression therapy with hyperbaric oxygen (HBO). Non-recompressive therapies are needed to address mass casualty scenarios such as a disabled submarine rescue or DCS therapy in remote environments. Intravenously delivered perfluorocarbon (PFC) emulsions improve blood oxygen content and decrease mortality in several animal models of DCS. However, the enhanced oxygen delivery of PFC emulsions may increase CNS oxygen toxicity (seizures) risk when used in conjunction with HBO. We studied seizure latency and duration in swine randomized to receive PFC or normal saline with 6 ATA of oxygen. METHODS Yorkshire swine (n = 31) were fitted with EEG electrodes and randomized to receive 5 ml/kg of the PFC Oxycyte (Oxygen Biotherapeutics Inc., Morrisville, NC) or saline intravenously 1 h before HBO. Unsedated animals were fitted with a snout mask for inhaled gas delivery, positioned inside the hyperbaric chamber, and compressed to 165 ft of sea water (6 ATA). After 2.5 min at 6 ATA, breathing gas was switched to 100 % O2 until signs of seizure were observed and EEG activity was evident. At seizure onset gas was switched back to air for 3 min, then the chamber was decompressed. After 24 h, the dive profile/oxygen exposure was repeated to ensure no secondary effects of PFC drug redistribution or emulsion metabolism. RESULTS/CONCLUSION Intravenous PFC emulsion did not decrease seizure latency or increase duration on initial HBO exposure or after 24 h. This finding demonstrates the safety of PFC use in conjunction with recompression therapy to treat DCS.
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Affiliation(s)
- Richard T Mahon
- Undersea Medicine Department, Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD, 20910-7500, USA,
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Pilla R, Held HE, Landon CS, Dean JB. High doses of pseudoephedrine hydrochloride accelerate onset of CNS oxygen toxicity seizures in unanesthetized rats. Neuroscience 2013; 246:391-6. [PMID: 23624060 DOI: 10.1016/j.neuroscience.2013.04.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/15/2013] [Accepted: 04/16/2013] [Indexed: 11/16/2022]
Abstract
Pseudoephedrine (PSE) salts (hydrochloride and sulfate) are commonly used as nasal and paranasal decongestants by scuba divers. Anecdotal reports from the Divers Alert Network suggest that taking PSE prior to diving while breathing pure O₂ increases the risk for CNS oxygen toxicity (CNS-OT), which manifests as seizures. We hypothesized that high doses of PSE reduce the latency time to seizure (LS) in unanesthetized rats breathing 5 atmospheres absolute (ATA) of hyperbaric oxygen. Sixty-three male rats were implanted with radio-transmitters that recorded electroencephalogram activity and body temperature. After ≥7-day recovery, and 2 h before "diving", each rat was administered either saline solution (control) or PSE hydrochloride intragastrically at the following doses (mg PSE/kg): 0, 40, 80, 100, 120, 160, and 320. Rats breathed pure O₂ and were dived to 5ATA until the onset of behavioral seizures coincident with neurological seizures. LS was the time elapsed between reaching 5ATA and exhibiting seizures. We observed a significant dose-dependent decrease in the LS at doses of 100-320 mg/kg, whereas no significant differences in LS from control value were observed at doses ≤80 mg/kg. Our findings showed that high doses of PSE accelerate the onset of CNS-OT seizures in unanesthetized rats breathing 5ATA of poikilocapnic hyperoxia. Extrapolating our findings to humans, we conclude that the recommended daily dose of PSE should not be abused prior to diving with oxygen-enriched gas mixes or pure O₂.
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Affiliation(s)
- R Pilla
- Department of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, 12901 Bruce B. Downs Boulevard, University of South Florida, Morsani College of Medicine, MDC 8, Tampa, FL 33612, United States
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Pilla R, Landon CS, Dean JB. A potential early physiological marker for CNS oxygen toxicity: hyperoxic hyperpnea precedes seizure in unanesthetized rats breathing hyperbaric oxygen. J Appl Physiol (1985) 2013; 114:1009-20. [PMID: 23429869 DOI: 10.1152/japplphysiol.01326.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hyperbaric oxygen (HBO(2)) stimulates presumptive central CO2-chemoreceptor neurons, increases minute ventilation (V(min)), decreases heart rate (HR) and, if breathed sufficiently long, produces central nervous system oxygen toxicity (CNS-OT; i.e., seizures). The risk of seizures when breathing HBO(2) is variable between individuals and its onset is difficult to predict. We have tested the hypothesis that a predictable pattern of cardiorespiration precedes an impending seizure when breathing HBO2. To test this hypothesis, 27 adult male Sprague-Dawley rats were implanted with radiotelemetry transmitters to assess diaphragmatic/abdominal electromyogram, electrocardiogram, and electroencephalogram. Seven days after surgery, each rat was placed in a sealed, continuously ventilated animal chamber inside a hyperbaric chamber. Both chambers were pressurized in parallel using poikilocapnic 100% O(2) (animal chamber) and air (hyperbaric chamber) to 4, 5, or 6 atmospheres absolute (ATA). Breathing 1 ATA O(2) initially decreased V(min) and HR (Phase 1 of the compound hyperoxic ventilatory response). With continued exposure to normobaric hyperoxia, however, V(min) began increasing toward the end of exposure in one-third of the animals tested. Breathing HBO2 induced an early transient increase in V(min) (Phase 2) and HR during the chamber pressurization, followed by a second significant increase of V(min) ≤8 min prior to seizure (Phase 3). HR, which subsequently decreased during sustained hyperoxia, showed no additional changes prior to seizure. We conclude that hyperoxic hyperpnea (Phase 3 of the compound hyperoxic ventilatory response) is a predictor of an impending seizure while breathing poikilocapnic HBO(2) at rest in unanesthetized rats.
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Affiliation(s)
- Raffaele Pilla
- Department of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, University of South Florida, Morsani College of Medicine, Tampa, FL 33612, USA
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Current World Literature. Curr Opin Anaesthesiol 2013; 26:98-104. [DOI: 10.1097/aco.0b013e32835cb4f0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Response to correspondence: “The link between inhibition of nitric oxide metabolite production and reduction of LPS induced lung injury,” by Dr. Michael Eisenhut. Int Immunopharmacol 2012. [DOI: 10.1016/j.intimp.2012.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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