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Topic: Hypocapnia

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In the News (Sun 23 Jun 19)

  Hypocapnia - Wikipedia, the free encyclopedia
Hypocapnia, also sometimes known as acapnia, is a state in which the level of carbon dioxide in the blood is lower than normal.
Hypocapnia is sometimes induced in the treatment of certain medical emergencies, such as intracranial hypertension.
Self-induced hypocapnia through hyperventilation is the basis for the deadly schoolyard choking game.
en.wikipedia.org /wiki/Hypocapnia   (238 words)

 UpToDate Pathogenesis of central sleep apnea
Sleep state, hypocapnia, upper airway reflexes, and breathing instability may all have a contributing role in the absence of ventilatory motor output and the development of central apnea.
Hypocapnia during NREM sleep is a major cause of reduced ventilatory motor output in most patients with non-hypercapnic central apnea.
Similarly, although hypocapnia occurs during transient arousals from sleep, the occurrence of central apnea is probably minimized by the activation of STP.
patients.uptodate.com /print.asp?print=true&file=sleepdis/5428   (645 words)

 [No title]
Role of hypocapnia in the alveolar surfactant increase induced by free fatty acid intravenous infusion in the rabbit.
In the absence of significant variations of either myocardial contractility or left ventricular end-diastolic pressure, the changes of stroke volume and cardiac output (diminution because of hypocapnia, augmentation because of hypercapnia) were determined by alterations of systemic vascular resistance (augmentation because of hypocapnia, diminution because of hypercapnia).
However the effect of hypocapnia on oxygenation is complex and may result in worsening in patients with preexisting intrapulmonary shunt." "Both hypocapnia and hypercapnia were associated with an increased VA/Q inequality.
members.westnet.com.au /pkolb/peat3_r.txt   (4297 words)

 eMedicine - Respiratory Alkalosis : Article by Jackie A Hayes, MD, FCCP
Hypocapnia develops when the lungs remove more carbon dioxide than is produced in the tissues.
Acute hypocapnia causes a reduction of serum levels of potassium and phosphate secondary to increased cellular uptake of these ions.
Cardiovascular effects of hypocapnia in healthy and alert patients are minimal, but in patients who are anesthetized, critically ill, or receiving mechanical ventilation, the effects can be more significant.
www.emedicine.com /med/topic2009.htm   (2228 words)

 6.4 Respiratory Alkalosis - Metabolic Effects
A chronic hypocapnia is associated with few symptoms because of the compensation that occurs.
It has been argued that these adverse effects of hypocapnia are significant enough that the Anaesthetist should aim to maintain normocapnia throughout the duration of anaesthesia in most cases.
One argument for routine intraoperative use of hypocapnia is to use the induced cerebral vasoconstriction to counteract the cerebral vasodilator effects of volatile anaesthetic agents.
www.anaesthesiamcq.com /AcidBaseBook/ab6_4.php   (522 words)

 Combined continuous monitoring of systemic and cerebral oxygenation in - Wheeless' Textbook of Orthopaedics
In response to transient profound hypocapnia, the cerebral oxygen extraction normalized (increased), as did the systemic-cerebral oxygenation index (decreased), under most circumstances.
CONCLUSIONS: In young adults with severe acute brain trauma who require prompt management of intracranial hypertension, transient profound hypocapnia is effective in lowering the intracranial pressure, as well as in offsetting the cerebral luxury perfusion, while improving or maintaining adequate systemic oxygenation.
The systemic -cerebral oxygenation index and the systemic-cerebral ventilatory index are potentially useful, physiologically monitorable variables for the combined assessment of global systemic and cerebral oxygenation in a variety of areas involving physiologic and/or therapeutic approaches.
www.wheelessonline.com /ortho/combined_continuous_monitoring_of_systemic_and_cerebral_oxygenation_in   (290 words)

 Ilse Van Diest, Ph D
Hyperventilation is a breathing pattern in excess of metabolic needs, leading to hypocapnia (a lowered CO2 pressure in the blood).
Study 8 investigated the extent to which the association of a symptom with NA could be predicted by its typicality for hyperventilation induced hypocapnia.
A last study (study 9) aimed to test whether the subjective symptoms of cognitive impairment associated with hypocapnia were mirrored in concomitant, objective cognitive performance deficits (Van Diest, Stegen, Van de Woestijne, Schippers, and Van de Woestijne, 2000).
ppw.kuleuven.be /rshw/ilse.htm   (805 words)

 carbon dioxide
Hypocapnia leads to cellular excitability and to increased contractility of the heart, increasing oxygen demand while oxygen availability is sharply decreased.
The seriousness of the effects of hypocapnia are made absolutely clear in the New England Journal of Medicine review article, written for the express purpose of warning physicians about their use of hypocapnia as a means to controlling symptoms and conditions resulting from injury and disease, as well as its widespread use in general anesthesia.
In fact, the impact of hypocapnia on cerebral blood flow and blood volume is so dramatic, according the article, that almost 50 percent of emergency physicians and 36 percent of neurosurgeons actually induce hypocapnia to control of life-threatening intracranial swelling resulting from head trauma or brain injury.
www.breathing.com /articles/carbon-dioxide.htm   (6153 words)

 Understanding carbon dioxide and respiratory rates
In addition to their possible hypocapnia, compensatory shallow breathing has other problems associated with the concurrent lack of diaphragmatic movement and increased anatomical dead space in the lungs including atelectasis and pneumonia.
In addition to its obvious role in respiration, the motion of the diaphragm is responsible for lymphatic circulation, its motion massages the internal organs helping with their intrinsic circulation and it also serves to stimulate the vagus nerve helping us stay in a relaxed state.
Exhaled CO Blood CO Subjects in the Major symptom range may experience all the effects of hypocapnia including increased pain, anxiety, insomnia, sleep disorders and asthma, but may not know that their symptoms are related to a common cause.
www.aetherin.com /co2andRR.htm   (1358 words)

 Hyperoxia-induced hypocapnia : an underappreciated risk CHEST - Find Articles   (Site not responding. Last check: 2007-10-09)
Administration of supplementary [O.sub.2] is considered to be safe, as exemplified by one editorial comment (1): "Oxygen should be used as soon as possible, in as near 100% as possible in all resuscitation situations, and for the early management of injury and illness.
Oxygen has long been known, but seldom recognized, to be a respiratory stimulant resulting in hypocapnia in adults (2-6) and infants (7-9) a result confirmed by more recent work.
Furthermore, the hypocapnia increases the affinity of hemoglobin for [O.sub.2], reducing [O.sub.2] unloading to tissues.
www.findarticles.com /p/articles/mi_m0984/is_1_128/ai_n15622409   (857 words)

 Splanchnic hemodynamics and gut mucosal-arterial PCO2 gradient during systemic hypocapnia -- Guzman and Kruse 87 (3): ...
layer, because mucosal perfusion was diminished by hypocapnia
Effects of hypocapnia on splanchnic circulation and hepatic function in the beagle.
Endotoxemia causes ileal mucosal acidosis in the absence of mucosal hypoxia in a normodynamic porcine model of septic shock.
jap.physiology.org /cgi/content/full/87/3/1102   (2434 words)

 Overbreathing and Its Consequences
When there is insufficient carbon dioxide in the body, the condition is known as hypocapnia (or hypocarbia), and it produces respiratory alkalosis, an acid-base imbalance.
Hypocapnia always results in narrowed arteries and veins, with associated high blood pressure (hypertension).
But when asleep, with hypocapnia present, the CO signal to the brain stem is missing, and breathing stops until the CO level rises enough to trigger the breathing reflex.
www.mindiskey.com /Stress.html   (1120 words)

 Research Activities, May 2002: Outcomes/Effectiveness Research: Mechanical ventilation of low birthweight newborns ...   (Site not responding. Last check: 2007-10-09)
Mechanical ventilation of newborns can result in hypocapnia (low levels of carbon dioxide in the blood) and hyperoxia (high levels of oxygen in the blood), both of which can result in reduced cerebral blood flow.
Ventilated newborns with hypocapnia, hyperoxia, or unusually prolonged duration of ventilation support have a two- to three-fold increased risk of being diagnosed with disabling cerebral palsy (DCP) by age 2, according to a study supported by the Agency for Healthcare Research and Quality (HS08385).
DCP was subsequently diagnosed in 2.3 percent of the 257 unventilated newborns, 9.4 percent of the 320 ventilated newborns without exposure to unusual levels of hypocapnia, and 27.5 percent of the 80 ventilated infants with exposure to significant hypocapnia.
www.ahrq.gov /research/may02/0502RA9.htm   (449 words)

 Permissive hypercapnia for the prevention of morbidity and mortality in mechanically ventilated newborn infants
The association of early hypocapnia and BPD was also present in those infants believed to have less severe lung disease.
Graziani et al (Graziani 1992) used logistic regression analysis to examine the relationships of perinatal factors, such as mechanical ventilation and hypocapnia, to the subsequent occurrence of neurodevelopmental and neurosonographic abnormalities.
However, hypocapnia resulting from the hyperventilation in PPHN management has been shown to be associated with an increased risk for sensorineural hearing loss (Hendricks-Munoz 1988) and low psychomotor developmental test scores (Ferrara 1984).
www.nichd.nih.gov /cochrane/Woodgate/Woodgate.htm   (4951 words)

 Hypocapnia attenuates mesenteric ischemia-reperfusion injury in a rat model: [L'hypocapnie attenue la lesion ...
Hypocapnia attenuates mesenteric ischemia-reperfusion injury in a rat model: [L'hypocapnie attenue la lesion mesenterique d'ischemie-reperfusion chez un modele rat] -- Duggan et al.
Hypocapnia attenuates mesenteric ischemia-reperfusion injury in a rat model
was impaired by ischemia-reperfusion but not by hypocapnia.
www.cja-jca.org /cgi/content/abstract/52/3/262   (289 words)

 Caudoputamen Is Damaged by Hypocapnia During Mechanical Ventilation in a Rat Model of Chronic Cerebral Hypoperfusion -- ...
Caudoputamen Is Damaged by Hypocapnia During Mechanical Ventilation in a Rat Model of Chronic Cerebral Hypoperfusion -- Miyamoto et al.
Note the marked vacuole formation in the fiber bundles of the caudoputamen in rats with chronic cerebral hypoperfusion and hypocapnia (A) in comparison to rats with either chronic cerebral hypoperfusion and normocapnia (B) or sham operation and hypocapnia (C).
increased by hypocapnia in rats with chronic cerebral hypoperfusion,
stroke.ahajournals.org /cgi/content/full/32/12/2920   (3545 words)

 Ophthalmic artery blood flow velocity increases during hypocapnia: [La vitesse circulatoire de l'artere ophtalmique ...
The purpose of this study is to determine the effects of hypocapnia
hypocapnia to hypercapnia, CO -reactivity was calculated for
in monkeys decreases with hypocapnia and increases with hypercapnia.
www.cja-jca.org /cgi/content/full/51/4/388   (2105 words)

 Human pulmonary vascular response to 4 h of hypercapnia and hypocapnia measured using Doppler echocardiography -- ...
Human pulmonary vascular response to 4 h of hypercapnia and hypocapnia measured using Doppler echocardiography -- Balanos et al.
B: hypocapnia protocol involved 4 h of euoxic hypocapnia with passive hyperventilation, followed by 2 h of euoxic eucapnia with spontaneous ventilation.
Circles, hypercapnia protocol; squares, hypocapnia protocol; triangles, control protocol; closed symbols, measurements made under hypercapnic (hypercapnia protocol) or hypocapnic (hypocapnia protocol) conditions; open symbols, measurements made under eucapnic conditions.
jap.physiology.org /cgi/content/full/94/4/1543   (3823 words)

 Preserved hypocapnic pial arteriolar constriction during hyperammonemia by glutamine synthetase inhibition -- Hirata et ...
with hyperammonemia is ameliorated by hypocapnia, thereby passively
CBF response to hypocapnia is attributed to disturbances in vascular
Blood flow to cerebrum during normocapnia and hypocapnia after 6 h of infusion of sodium acetate or ammonium acetate in groups pretreated with vehicle, MSO, or BSO.
ajpheart.physiology.org /cgi/content/full/276/2/H456   (3668 words)

 [No title]
Hypocapnia is the result of overbreathing behavior, the mismatch of breathing rate and depth.
Its consequence is an increased level of pH, or respiratory alkalosis, which may have profound immediate and long-term effects that trigger, exacerbate, and/or cause a wide variety of emotional, perceptual, cognitive, attention, behavioral, and physical deficits that may seriously impact health and performance.
Hypocapnia may play a significant role in many of these cases, where it may mediate homeostatic deregulation attributed to stress.
www.wilddivine.com /june06drpeterlitchfield   (949 words)

 Deep water blackout - Wikipedia, the free encyclopedia
This problem probably stems from the original identification of the mechanism of latent hypoxia arising in the context of a string of fatal, shallow water accidents with early military, closed-circuit rebreather apparatus prior to the development of effective partial pressure oxygen meters.
The primary mechanism for shallow water flout is hypocapnia brought about by hyperventilation prior to the dive.
Hyperventilation leading to hypocapnia and subsequent loss of an appropriate urge to breathe is the mechanism behind shallow water flout; refer to the shallow water flout article for a detailed description of how this commonly misunderstood mechanism works.
en.wikipedia.org /wiki/Deep_water_blackout   (1994 words)

 Hypocapnia reduces the T wave of the electrocardiogram in normal human subjects -- Rutherford et al. 289 (1): R148 -- ...
Hypocapnia reduces the T wave of the electrocardiogram in normal human subjects -- Rutherford et al.
A: lack of effect of hypocapnia on blood ionized calcium levels for all subjects during normocapnia at constant inflation volume with air, hypocapnia at constant inflation volume with air, and hypocapnia at constant inflation volume with O
Role of hypocapnia in the circulatory responses to acute hypoxia in man. J Appl Physiol 21: 22–26, 1966.
ajpregu.physiology.org /cgi/content/full/289/1/R148   (4556 words)

 Do hyperoxaemia and hypocapnia add to the risk of brain injury after intrapartum asphyxia? -- Klinger et al. 90 (1): ...
Hypocapnia in animals is known to decrease cerebral blood flow,
Two levels of hyperoxaemia and hypocapnia were defined as follows.
hypocapnia and hyperoxaemia occurred in 38% and 25% of preterm
fn.bmj.com /cgi/content/full/90/1/F49   (2680 words)

 Injurious Effects of Hypocapnic Alkalosis in the Isolated Lung -- LAFFEY et al. 162 (2): 399 -- American Journal of ...
Although the levels of hypocapnia examined in this study are severe, they are of human relevance in several contexts.
Airway hypocapnia increases microvascular leakage in the guinea pig trachea.
Effect of hypocapnia on pulmonary mechanics in normal subjects and in patients with chronic obstructive lung disease.
ajrccm.atsjournals.org /cgi/content/full/162/2/399   (4359 words)

 Hypocapnia and Other Ventilation-Related Risk Factors for Cerebral Palsy in Low Birth Weight Infants -- COLLINS et al. ...   (Site not responding. Last check: 2007-10-09)
Hypocapnia and Other Ventilation-Related Risk Factors for Cerebral Palsy in Low Birth Weight Infants -- COLLINS et al.
Prevalence of DCP in ventilated newborns by quintiles of cumulative hypocapnia exposure
have tended to concentrate on the effects of marked hypocapnia.
www.pedresearch.org /cgi/content/full/50/6/712   (5058 words)

 Hypocapnia Under Hypotension Induces Apoptotic Neuronal Cell Death in the Hippocampus of Newborn Rabbits -- OHYU et al. ...   (Site not responding. Last check: 2007-10-09)
Hypocapnia Under Hypotension Induces Apoptotic Neuronal Cell Death in the Hippocampus of Newborn Rabbits -- OHYU et al.
Hypocapnia Under Hypotension Induces Apoptotic Neuronal Cell Death in the Hippocampus of Newborn Rabbits
Greisen G, Munck H, Lou H 1987 Severe hypocapnia in preterm infants and neurodevelopmental deficit.
www.pedresearch.org /cgi/content/full/48/1/24   (2881 words)

 e-Prints Soton - Hypocapnia and asthma: a mechanism for breathing retraining?
There is some evidence that breathing retraining may be beneficial for patients with asthma, but the mechanism behind this benefit is still unknown.
One hypothesis is that individuals can be trained to raise carbon dioxide levels and thereby reverse the bronchoconstrictive effects of hypocapnia and utilize the bronchodilatory effects of hypercapnia.
This article reviews the available evidence supporting the hypothesis and concludes that although attractive, there is currently insufficient evidence to attribute the benefits of breathing retraining to this mechanism.
eprints.soton.ac.uk /17833   (184 words)

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