WordNet

pertaining to respiration; "respiratory assistance"
abnormally high acidity (excess hydrogen-ion concentration) of the blood and other body tissues
a breathing device for administering long-term artificial respiration (同)inhalator

PrepTutorEJDIC

呼吸の,呼吸作用の,呼吸のための
酸性症,酸中毒(血液中のアルカリ濃度が異常に低い状態)
《米》人工呼吸装置 / (一般に)マスク;防毒マスク

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/05/30 21:09:59」(JST)

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Respiratory acidosis is a medical condition in which decreased ventilation (hypoventilation) causes increased blood carbon dioxide concentration and decreased pH (a condition generally called acidosis).

Carbon dioxide is produced continuously as the body's cells respire, and this CO₂ will accumulate rapidly if the lungs do not adequately expel it through alveolar ventilation. Alveolar hypoventilation thus leads to an increased PaCO₂ (called hypercapnia). The increase in PaCO₂ in turn decreases the HCO₃⁻/PaCO₂ ratio and decreases pH.

Terminology

Acidosis refers to disorders that lower cell/tisue pH to < 7.35.
Acidemia refers to a arterial pH < 7.35.

Types of respiratory acidosis

Respiratory acidosis can be acute or chronic.

In acute respiratory acidosis, the PaCO₂ is elevated above the upper limit of the reference range (over 6.3 kPa or 47 mm Hg) with an accompanying acidemia (pH <7.35).
In chronic respiratory acidosis, the PaCO₂ is elevated above the upper limit of the reference range, with a normal blood pH (7.35 to 7.45) or near-normal pH secondary to renal compensation and an elevated serum bicarbonate (HCO₃⁻ >30 mm Hg).

Causes

Acute

Acute respiratory acidosis occurs when an abrupt failure of ventilation occurs. This failure in ventilation may be caused by depression of the central respiratory center by cerebral disease or drugs, inability to ventilate adequately due to neuromuscular disease (e.g., myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, muscular dystrophy), or airway obstruction related to asthma or chronic obstructive pulmonary disease (COPD) exacerbation.

Chronic

Chronic respiratory acidosis may be secondary to many disorders, including COPD. Hypoventilation in COPD involves multiple mechanisms, including decreased responsiveness to hypoxia and hypercapnia, increased ventilation-perfusion mismatch leading to increased dead space ventilation, and decreased diaphragm function secondary to fatigue and hyperinflation.

Chronic respiratory acidosis also may be secondary to obesity hypoventilation syndrome (i.e., Pickwickian syndrome), neuromuscular disorders such as amyotrophic lateral sclerosis, and severe restrictive ventilatory defects as observed in interstitial fibrosis and thoracic deformities.

Lung diseases that primarily cause abnormality in alveolar gas exchange usually do not cause hypoventilation but tend to cause stimulation of ventilation and hypocapnia secondary to hypoxia. Hypercapnia only occurs if severe disease or respiratory muscle fatigue occurs.

Physiological response

Mechanism

Metabolism rapidly generates a large quantity of volatile acid (H₂CO₃) and nonvolatile acid. The metabolism of fats and carbohydrates leads to the formation of a large amount of CO₂. The CO₂ combines with H₂O to form carbonic acid (H₂CO₃). The lungs normally excrete the volatile fraction through ventilation, and acid accumulation does not occur. A significant alteration in ventilation that affects elimination of CO₂ can cause a respiratory acid-base disorder. The PaCO₂ is maintained within a range of 35–45 mm Hg in normal states.

Alveolar ventilation is under the control of the central respiratory centers, which are located in the pons and the medulla. Ventilation is influenced and regulated by chemoreceptors for PaCO₂, PaO₂, and pH located in the brainstem,and in the aortic and carotid bodies as well as by neural impulses from lung stretch receptors and impulses from the cerebral cortex. Failure of ventilation quickly increases the PaCO₂.

In acute respiratory acidosis, compensation occurs in 2 steps.

The initial response is cellular buffering that occurs over minutes to hours. Cellular buffering elevates plasma bicarbonate (HCO₃⁻) only slightly, approximately 1 mEq/L for each 10-mm Hg increase in PaCO₂.
The second step is renal compensation that occurs over 3–5 days. With renal compensation, renal excretion of carbonic acid is increased and bicarbonate reabsorption is increased. For instance, PEPCK is upregulated in renal proximal tubule brush border cells, in order to secrete more NH₃ and thus to produce more HCO₃⁻.^[1]

Estimated changes

In renal compensation, plasma bicarbonate rises 3.5 mEq/L for each increase of 10 mm Hg in PaCO₂. The expected change in serum bicarbonate concentration in respiratory acidosis can be estimated as follows:

Acute respiratory acidosis: HCO₃⁻ increases 1 mEq/L for each 10 mm Hg rise in PaCO₂.

Chronic respiratory acidosis: HCO₃⁻ rises 3.5 mEq/L for each 10 mm Hg rise in PaCO₂.

The expected change in pH with respiratory acidosis can be estimated with the following equations:

Acute respiratory acidosis: Change in pH = 0.008 X (40 − PaCO₂)

Chronic respiratory acidosis: Change in pH = 0.003 X (40 − PaCO₂)

Respiratory acidosis does not have a great effect on electrolyte levels. Some small effects occur on calcium and potassium levels. Acidosis decreases binding of calcium to albumin and tends to increase serum ionized calcium levels. In addition, acidemia causes an extracellular shift of potassium, but respiratory acidosis rarely causes clinically significant hyperkalemia.

References

^ Walter F., PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 858

External links

Physiology at MCG 7/7ch12/7ch12p43

UpToDate Contents

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1. 高炭酸ガス血症患者における酸素の使用 use of oxygen in patients with hypercapnia
2. 単純性および混合性酸塩基障害 simple and mixed acid base disorders
3. 高二酸化炭素血症の許容（Permissive hypercapnia） permissive hypercapnia
4. 換気調節障害 disorders of ventilatory control
5. 慢性閉塞性肺疾患（COPD）：予後因子および併存疾患 chronic obstructive pulmonary disease prognostic factors and comorbid conditions

English Journal

Safety of carbonic anhydrase inhibitors.

Swenson ER.Author information University of Washington - Medical Service, VA Puget Sound Health Care System , 1660 S Columbian Way, S-111-PLUM, Seattle, WA 98108 , USA Erik.Swenson@va.gov.AbstractIntroduction: Carbonic anhydrase (CA) inhibitors have an impressive safety record despite the multiple functions that CA isozymes serve because they are not fully inhibited with most dosing. While reducing the targeted CA-dependent process sufficiently for disease control, residual activity and uncatalyzed rates in combination with compensations are adequate to avoid lethal consequences. Some drugs have in vitro selectivity differences against the 13 active isozymes, but none are convincingly selective in vivo or clinically. Efforts to synthesize selective inhibitors should result in safer drugs with fewer side effects. Areas covered: This review will focus on approved drugs with CA-inhibiting activity, whether used directly for this purpose or others. Side effects are discussed in relation to various organ systems and the disease being treated. Causes of side effects are considered, and strategies for symptom reduction are given. Expert opinion: Common side effects of paresthesias, dyspepsia, lassitude and fatigue in 30 - 40% of patients are generally tolerable or abate, but if not can be partially relieved by bicarbonate supplementation. The most important safety concerns are severe acidosis, respiratory failure and encephalopathy in patients with renal, pulmonary and hepatic disease where caution is critical, as is also the case in persons with sulfa drug allergies.
Expert opinion on drug safety.Expert Opin Drug Saf.2014 Apr;13(4):459-72. doi: 10.1517/14740338.2014.897328. Epub 2014 Mar 10.
Introduction: Carbonic anhydrase (CA) inhibitors have an impressive safety record despite the multiple functions that CA isozymes serve because they are not fully inhibited with most dosing. While reducing the targeted CA-dependent process sufficiently for disease control, residual activity and unca
PMID 24611470

Mutations in the lipoyltransferase LIPT1 gene cause a fatal disease associated with a specific lipoylation defect of the 2-ketoacid dehydrogenase complexes.

Tort F1, Ferrer-Cortès X, Thió M, Navarro-Sastre A, Matalonga L, Quintana E, Bujan N, Arias A, García-Villoria J, Acquaviva C, Vianey-Saban C, Artuch R, García-Cazorla A, Briones P, Ribes A.Author information 1Secció d'Errors Congènits del Metabolisme, Servei de Bioquímica i Genètica Molecular, Hospital Clinic, IDIBAPS, C/Mejía Lequerica s/n, Barcelona 08028, Spain.AbstractCofactor disorders of mitochondrial energy metabolism are a heterogeneous group of diseases with a wide variety of clinical symptoms, particular metabolic profiles and variable enzymatic defects. Mutations in NFU1, BOLA3, LIAS and IBA57 have been identified in patients with deficient lipoic acid-dependent enzymatic activities and defects in the assembly and activity of the mitochondrial respiratory chain complexes. Here, we report a patient with an early onset fatal lactic acidosis presenting a biochemical phenotype compatible with a combined defect of pyruvate dehydrogenase (PDHC) and 2-ketoglutarate dehydrogenase (2-KGDH) activities, which suggested a deficiency in lipoic acid metabolism. Immunostaining analysis showed that lipoylated E2-PDH and E2-KGDH were extremely reduced in this patient. However, the absence of glycine elevation, the normal activity of the glycine cleavage system and the normal lipoylation of the H protein suggested a defect of lipoic acid transfer to particular proteins rather than a general impairment of lipoic acid biosynthesis as the potential cause of the disease. By analogy with yeast metabolism, we postulated LIPT1 as the altered candidate gene causing the disease. Sequence analysis of the human LIPT1 identified two heterozygous missense mutations (c.212C>T and c.292C>G), segregating in different alleles. Functional complementation experiments in patient's fibroblasts demonstrated that these mutations are disease-causing and that LIPT1 protein is required for lipoylation and activation of 2-ketoacid dehydrogenases in humans. These findings expand the spectrum of genetic defects associated with lipoic acid metabolism and provide the first evidence of a lipoic acid transfer defect in humans.
Human molecular genetics.Hum Mol Genet.2014 Apr 1;23(7):1907-15. doi: 10.1093/hmg/ddt585. Epub 2013 Nov 20.
Cofactor disorders of mitochondrial energy metabolism are a heterogeneous group of diseases with a wide variety of clinical symptoms, particular metabolic profiles and variable enzymatic defects. Mutations in NFU1, BOLA3, LIAS and IBA57 have been identified in patients with deficient lipoic acid-dep
PMID 24256811

Japanese Journal

Mitochonic Acid 5 (MA-5), a Derivative of the Plant Hormone Indole-3-Acetic Acid, Improves Survival of Fibroblasts from Patients with Mitochondrial Diseases

Suzuki Takehiro,Yamaguchi Hiroaki,Kikusato Motoi,Matsuhashi Tetsuro,Matsuo Akihiro,Sato Takeya,Oba Yuki,Watanabe Shun,Minaki Daichi,Saigusa Daisuke,Shimbo Hiroko,Mori Nobuyoshi,Mishima Eikan,Shima Hisato,Akiyama Yasutoshi,Takeuchi Yoichi,Yuri Akinori,Kikuchi Koichi,Toyohara Takafumi,Suzuki Chitose,Kohzuki Masahiro,Anzai Jun-ichi,Mano Nariyasu,Kure Shigeo,Yanagisawa Teruyuki,Tomioka Yoshihisa,Toyomizu Masaaki,Ito Sadayoshi,Osaka Hitoshi,Hayashi Ken-ichiro,Abe Takaaki
The Tohoku Journal of Experimental Medicine 236(3), 225-232, 2015
… Mitochondrial diseases are characterized by the dysfunction of the mitochondrial respiratory chain, caused by mutations in the genes encoded by either nuclear DNA or mitochondrial DNA. … Importantly, MA-5 improved the survival of fibroblasts established from patients with mitochondrial diseases under the stress-induced condition, including Leigh syndrome, MELAS (myopathy encephalopathy lactic acidosis and stroke-like episodes), Leber's hereditary optic neuropathy, and Kearns-Sayre syndrome. …
NAID 130005083526

小児科におけるミトコンドリア病

古賀靖敏
神経眼科 31(4), 457-463, 2014
ミトコンドリア病は，ミトコンドリアのエネルギー産生系酵素の遺伝的異常により引き起こされる難治性進行性疾患である．エネルギー産生障害を伴うことから，エネルギー依存度の高い中枢神経系，骨格筋，心筋などの臓器障害を来す事が多い．意識障害，けいれんを主訴に来院する場合も多く，それらの原因となる他の疾患を除外する必要がある．小児期におけるミトコンドリア病は，成人発症と比較し，発症様式，臨床症状，経過，予後な …
NAID 130005057117

筋疾患とミトコンドリア病

大越教夫,石井亜紀子
神経眼科 31(4), 446-456, 2014
ミトコンドリア病は，ミトコンドリアDNAあるいは核DNA異常によって生じるミトコンドリアの呼吸鎖電子伝達系障害により多彩な臨床症状を来す疾患の総称である．障害されやすい臓器は，骨格筋，中枢神経系，心臓であり，特にミオパチーでは，外眼筋と四肢・体幹の骨格筋が障害されやすい．外眼筋症状はミトコンドリア病診断の重要症状の一つで，極めてゆっくり進行する眼瞼下垂と外眼筋麻痺を特徴とする．四肢の筋力低下は通常 …
NAID 130005057116

Related Pictures

★リンクテーブル★

リンク元	「呼吸性アシドーシス」
関連記事	「respiratory」「acidosis」

「呼吸性アシドーシス」

Respiratory acidosis
	Classification and external resources
	Davenport diagram
ICD-10	E87.2
ICD-9	276.2
DiseasesDB	95
MedlinePlus	000092
MeSH	D000142

　　[★]

英: respiratory acidosis
関: アシドーシス、酸塩基平衡異常

酸塩基平衡異常とその代償 SP.660

	HCO3-	pCO2
呼吸性アシドーシス	↑	↑
呼吸性アルカローシス	↓	↓
代謝性アシドーシス	↓	↑
代謝性アルカローシス	↑	↓

原因

呼吸不全

pocket medicine

CNS抑制：鎮静薬、CNS外傷、慢性高CO2血症での酸素使用(低酸素による換気ドライブ低下)
神経筋疾患：重症筋無力症、GBS、ポリオ関連脊髄炎、ALS、筋ジストロフィ、重症点リン酸血症
上気道異常：急性気道閉塞、喉頭痙攣、閉塞性睡眠時無呼吸、食道挿管
下気道異常：喘息、COPD
肺実質障害(頻繁に低酸素血症を起こす→RR↑→呼吸性アルカローシス。最終的には呼吸筋疲労により呼吸性アシドーシス)：肺炎、肺水腫、拘束性肺障害
胸郭構造異常→気胸、動揺胸郭(フレイルチェスト)、後側彎症
分時換気量改善能に限界のあるアシドーシス患者へのHCO3 IV後

代償変化

腎臓でのHCO3-の再吸収亢進

「respiratory」

　　[★]

adj.

呼吸の、呼吸器の、呼吸性の

関: breath、breathe、breathing、respiration、respiratory mechanics、respiratory organ、respiratory tract

「acidosis」

　　[★] アシドーシス

[boron858-1] Walter F., PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 858

匿名

検索

案内

案内

respiratory acidosis