Hypocapnia

10/01/2002 - "Further physiologic benefits include improved oxygen delivery and neuroprotection, the latter through both avoidance of accidental hypocapnia, which is associated with a poor neurologic outcome, and direct cellular effects. "
09/28/2022 - "Methods: Ten healthy participants performed a 60-s cycling exercise at a workload of 120% peak oxygen uptake in control (spontaneous breathing), hypocapnia and normocapnia trials. "
08/01/2017 - "Oxygen uptake ([Formula: see text]) was lower in the hypocapnia than control trials (822 ± 235 vs. 1645 ± 245 mL min-1; mean ± SD) during Ex1, but not Ex2 or Ex3, without a between-trial difference in the power output during the exercises. "
11/01/1986 - "The present study was performed first to examine whether a maximal decline in coronary sinus (CS) oxygen content was reached during hypocapnia. "
12/01/2019 - "We measured how long is a second breath-hold if we prematurely terminate a single, prolonged breath-hold of >5 min either by using a single breath of oxygen (O2), or by reintroducing preoxygenation and hypocapnia. "

01/01/1995 - "Severe hypocapnia (< 20 mmHg) may result in cerebral production of lactate; however no studies have shown that a Paco2 in the range of 23-28 mmHg has deleterious effects. "
04/01/2003 - "However, despite continuing hypocapnia there is secondary recovery of CBF over time as a result of increases in lactic acid production. "
11/01/2002 - "In protocol 3, i.v EtOH produced small but significant changes in Scvo, intracranial pressure, and lactate, at normo-, hyper-, and hypocapnia. "
09/01/1994 - "One patient had elevated CSF lactate when she was younger and her HV was more intensive, but now her CSF and blood lactate were normal; her acid-base balance showed mild hypocapnia but was otherwise normal. "
06/01/1988 - "The relationship between striated muscle tissue oxygenation during hyper- and hypocapnia, and lactate levels and venous pO2 (pvO2) was studied in a rabbit model. "

10/01/1989 - "The specificity of this adaptation was supported by showing that Na+-dependent uptake of D-[3H]glucose by BBMV was not significantly different between chronic hypocapnia and control. "
03/01/1989 - "The effect of hypocapnia on regional cerebral glucose utilization (L-CMRg) was studied in 14 Sprague Dawley rats. "
03/01/1989 - "Effect of hypocapnia on local cerebral glucose utilization in rats."
03/01/1989 - "In the hypocapnic group glucose decreased from 71 +/- 3 to 19 +/- 2 mg/100 ml. CBF decreased with hypocapnia to 62 +/- 5% of control in NG but remained at control in HG. This was not accompanied by changes in cerebral oxygen consumption; however, a flat EEG occurred in all HG hypocapnic animals. "
11/01/1982 - "Transfer across the human blood-brain barrier: evidence for capillary recruitment and for a paradox glucose permeability increase in hypocapnia."

12/01/1999 - "Our findings warrant cautious interpretation of Pico2 - Paco2 as an indicator of splanchnic perfusion during systemic hypocapnia."
10/01/2001 - "After induction of anaesthesia, repeated cerebral blood flow measurements using transcerebral double-indicator dilution were performed during target normocapnia, hypocapnia and hypercapnia. "
01/01/1989 - "Since hypoxemia is not known to be a sensitive indicator of acute pulmonary embolism, we performed a retrospective study to determine whether an increased P(A-a)O2 gradient or hypocapnia improved the sensitivity of blood gas analysis in acute embolism. "
08/01/1989 - "The clinical diagnosis of sepsis is based on the finding of an obvious septic focus with the presence of at least four of the following 5 criteria: (I) fever above 38.8 degrees C or hypothermia below 35.5 degrees C; (II) tachypnoea (greater than 24/min) or hypocapnia (PaCO2 less than 32 mmHg); (III) tachycardia (greater than 100 Bpm), (IV) leucocytosis (greater than or equal to 15.000/mm3) or leucopenia (greater than 5.000/mm3); (V) presence of at least one indicator for inadequate organ perfusion like mental alterations, hypoxaemia (PaCO2 less than 75 mmHg while breathing room air), hyperlactataemia (greater than 1,6 mmol/l), diuresis below 30 ml/h, drop in systolic blood pressure below 100 mmHg. "
10/01/1983 - "It was demonstrated that T-wave inversion could not be a reliable indicator of coronary insufficiency, nor could respiratory alkalosis, hypocapnia, tachycardia, increased work of respiratory muscles, hypoxemia be immediate causes of hyperventilation changes. "

03/15/2011 - "In all cases, increased phrenic burst amplitude was observed following restoration of respiratory neural activity (hypocapnia: 92±22%; isoflurane: 65±22%; HFV: 54±13% baseline), which was significantly greater than time controls receiving the same surgery, but no interruptions in respiratory neural activity (3±5% baseline, p<0.05). "
05/01/2005 - "Hypocapnia restored cerebral autoregulation in normal subjects during isoflurane-induced impairment of autoregulation."
05/01/2005 - "The effect of hypocapnia on the autoregulation of cerebral blood flow during administration of isoflurane."
11/01/1994 - "The results show that during hypocapnia isoflurane causes significant reductions in MAP and CCP whereas ICP and CFV tend to diminish but not significantly. "
03/01/1991 - "In animals receiving isoflurane and subjected to hypocapnia, total CBF during normocapnia at 1 h was 97 +/- 10 ml min 100 g and declined to 56 +/- 9 ml min 100 g at 3 hr (p <0.05). "

02/01/1980 - "This study was performed to determine whether exercise produces vasodilatation in regions of the brain that are associated with motor functions despite the associated vasoconstrictor effect of hypocapnia. "
01/01/1989 - "Both of these situations can result in a reduction of CBF to brain tissue, mainly for two reasons: 1) In the former, a further increase in vasospasm cannot be compensated for anymore when the peripheral arterioles are maximally dilated, and 2) in the latter, hypocapnia produces a strong peripheral vasoconstrictor response with further reduction of CBF."
01/01/1981 - "Pial arterioles from vehicle-treated animals displayed sustained dilation, reduced responsiveness to the vasoconstrictor effect of arterial hypocapnia, and a high density of endothelial lesions. "
02/01/1980 - "These results indicate that exercise in conscious dogs increases blood flow in regions of the brain associated with movement despite the associated vasoconstrictor stimulus of arterial hypocapnia. "
01/01/1980 - "The absence of an influence of the sympathetic nervous system on the responses to hypocapnia is explained by the lack of significant resting neurogenic vasoconstrictor tone in pial arterioles of anesthetized cats."

01/01/2003 - "The purpose of this study was to test whether constriction of the cerebral vasculature in response to respiration-induced hypocapnia was mimicked by isocapnic alkaline solution. "
01/01/2003 - "Thus, constriction to isocapnic alkaline solution does not mimic constriction to hypocapnia. "
01/01/2003 - "Constriction to hypocapnia was also reduced following isocapnic alkaline solution. "
01/01/2003 - "Since the regulation of the cerebral vasculature by hypocapnia necessitates vessels to constrict repeatedly in response to hypocapnic challenge, we tested whether repeated challenge with isocapnic alkaline solution was also associated with constriction. "
01/01/2003 - "Repeated constriction to respiration-induced hypocapnia is not mimicked by isocapnic alkaline solution in rabbit basilar artery in situ."

01/01/1982 - "Adenosine infusion during hypocapnia was least effective in dilating the coronary vasculature. "
11/01/1987 - "During continuous adenosine infusion (7.5 +/- 0.3 mg/kg/h) which increased MBF 116% during normocapnia, creating hypocapnia caused a 40% decrease in MBF. "
12/01/1985 - "Profound hypotension induced with adenosine does not eliminate CO2 reactivity, nor does it lower blood flow to ischemic levels in this model, even in the presence of severe hypocapnia."
11/01/1987 - "The present study was performed to examine if hypocapnia and hypercapnia might influence the sensitivity to exogenous administration of adenosine. "
12/01/1985 - "Cerebrovascular effects of hypocapnia during adenosine-induced arterial hypotension."

12/01/1990 - "In this model, prior institution of hypocapnia prevented nimodipine-induced global CBF increases."
12/01/1990 - "Hypocapnia decreased local CBF in all structures examined, whereas nimodipine increased local CBF in some, but not all structures. "
12/01/1990 - "Although nimodipine increased global CBF (p <0.05) during normocapnia (89 +/- 8 versus 61 +/- 4 ml/100 g/min), during hypocapnia there was no significant difference between nimodipine and vehicle (45 +/- 3 versus 40 +/- 2 ml/100 g/min). "
12/01/1990 - "Hypocapnia decreased global CBF (p <0.0001) and nimodipine increased CBF (p <0.05). "
12/01/1990 - "Animals were randomized into four experimental groups in a 2 x 2 factorial design, employing Paco2 level and drug group as between-group factors: vehicle plus normocapnia (group 1, n = 6), nimodipine plus normocapnia (group 2, n = 7), vehicle plus hypocapnia (group 3, n = 6), and nimodipine plus hypocapnia (group 4, n = 6). "

04/01/1992 - "CBF was significantly greater during normocapnia compared with hypocapnia at all levels of CPP, except at 35% of control when the values were similar. "
04/01/1992 - "In this study in dogs we investigated cerebral vascular responses to graded decreases of cerebral perfusion pressure (CPP) (100%, 60%, 45%, and 35% of control CPP) during normocapnia (PaCO2 = 37 mm Hg) and hypocapnia (PaCO2 = 21 mm Hg). "
01/01/2012 - "The consequences of moderate hypocapnia (HC) on the autoregulation of cerebral perfusion pressure (CPP) have not been monitored so far.Thirty"
09/16/2008 - "Despite marked changes in CPP, there were no evident change in transfer-function gain, coherence, MAP variability or BRS; however, both MCAv variability and phase in the very-low frequency range was reduced during the most severe level of hyper- and hypocapnia (P < 0.05), and were related to elevations in ventilation (R2 = 0.42-0.52, respectively; P < 0.001). "
11/01/2002 - "With EtOH, CPP was maintained and cerebral blood flow appeared to be adequate, if not excessive, with respect to cerebral metabolic demand, as judged by changes in Scvo at normo-, hyper-, and hypocapnia. "

12/01/2001 - "In the present study we investigated the effect of hypocapnia during anesthesia on neuronal damage using a rat model of chronic cerebral hypoperfusion. "
11/01/2019 - "Hypocapnia is a common alteration during anesthesia in neonates. "
02/01/2017 - "These results emphasize the importance of preventing hypocapnia during anesthesia to improve surgical outcomes."
01/15/2012 - "These results provide the first clear evidence that laboratory anesthesia can profoundly alter the regulation of ABs including the hypocapnia-dependent component of their facilitation."
07/01/2006 - "In conclusion, cerebrovascular response to hypocapnia is similar between the normal and the abnormal cerebral hemispheres both under intravenous and inhalational anesthesia."

09/01/2022 - "12.8% had hypocapnia, and in half of the cases it was severe necessitating modification of therapy. "
01/01/2006 - "i-NO therapy for PPHN might improve systemic oxygenation without excessive hypocapnia. "
10/01/2003 - "The idea that hypocapnia and respiratory irregularities are underlying factors in the development of panic implies that these factors should be monitored physiologically throughout therapy. "
04/07/2003 - "The ability to reduce blood flow and increase mean transit time through hypocapnia has significant implications in thermal therapy, since heat dissipation is a major factor in limiting the effectiveness of treatment."
07/01/2003 - "The average change in thermal lesion area at 60 min post-laser thermal therapy from pre-treatment normalized to the pre-treatment tumour area was significantly different between the two treatment protocols: 0.52+/-0.13 (hypocapnia) vs 0.33+/-0.12 (normocapnia) (p < 0.001). "

06/01/2016 - "During mechanical ventilation, the mean blood pressure did not change significantly, mean heart rate fell by 2 bpm (p < 0.05) with pre-oxygenation and rose by only 4 bpm (p < 0.05) during pre-oxygenation with hypocapnia. "
01/15/2010 - "Hypocapnia was induced via nasal mechanical ventilation for 3 minutes. "
01/01/2006 - "Hypocapnia was induced via nasal mechanical ventilation for 3 minutes during stable non-rapid eye movement sleep. "
12/01/2004 - "During NREM sleep, hypocapnia was induced via nasal mechanical ventilation. "
01/01/2003 - "Hypocapnia was induced via nasal mechanical ventilation (MV) for 3 min with tidal volumes ranging from 175 to 215% above eupneic tidal volume and respiratory frequency matched to eupneic frequency. "

12/01/2023 - "However, hypocapnia induced by LBNP contributes to cerebral blood flow reductions, and may mask potential protective effects of hemodynamic oscillations on cerebral blood flow. "
01/01/2020 - "In addition, although LBNP induced a mild hypocapnia, this degree of hypocapnia in the absence of LBNP failed to modify the NVC response."
01/01/2020 - "These findings indicate that the NVC is not influenced by LBNP or mild hypocapnia in humans.NEW & NOTEWORTHY Visual stimulation evoked a robust increase in posterior cerebral artery velocity and a modest increase in vertebral artery blood flow, i.e., neurovascular coupling (NVC), which was unaffected by lower body negative pressure (LBNP) in humans. "
01/01/2020 - "The mild hypocapnia during LBNP did not exert a confounding influence on the NVC response. "
01/01/2018 - "These findings indicate that hypocapnia accounted fully for the reduction in MCAvmean when passively heat stressed in the absence of LBNP and for two- thirds of the reduction when at heat tolerance combined with LBNP. "

01/01/2021 - "Normocapnia within the first 24-h of intensive care admission after OHCA was associated with an improved survival compared to patients with hypocapnia or hypercapnia."
01/01/1977 - "The effects of induced hypocapnia, hypothermia, and hypertension were surveyed in a primate model of acute stroke during and following a 48-hour period of intensive care. "
01/01/2023 - "We conclude that in healthy volunteers at rest, common situations observed during anesthesia and intensive care such as exposure to hypoxia, hyperoxia, hypocapnia, or hypercapnia, did not affect peripheral tissue O2 consumption and vascular reactivity as assessed by VOT-induced changes in StO2. "