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PubMed1974

Intracranial volume--pressure relationships during experimental brain compression in primates. 3. Effect of mannitol and hyperventilation.

In 10 anaesthetized and ventilated baboons a steady level of raised intracranial pressure was achieved by graduated inflation of an extradural balloon. Measurements were made of the ventricular fluid pressure, and of the change in this pressure after injection of 0·05 ml into the ventricle, the volume-pressure response. This response was studied at normocapnia and at hypocapnia (induced by hyperventilation), and before and after the intravenous administration of mannitol under normocapnic and hypercapnic conditions. During hypocapnia, ventricular fluid pressure and the volume-pressure response were reduced equally. Mannitol, however, caused a greater reduction in the volume-pressure response than in ventricular fluid pressure. The intravenous administration of mannitol therefore produces a beneficial effect on intracranial capacitance which is greater than observation of intracranial pressure alone indicates.

Animals↗
PubMed1976

Early venous filling and controlled hyperventilation in cerebral angiography.

Controlled hyperventilation is a useful adjunct to angiography of tumours and inflammatory disease, giving increased demonstration of normal penetrating arteries and abnormal vessels. This shunting effect commonly causes early filling of the deep ependymal veins which should not be mistaken for early venous return due to tumour. While the effect could theoretically mask early venous flow secondary to tumour, this has not been our experience.

Carbon Dioxide↗
PubMed1985

Bronchial challenge with room temperature isocapnic hyperventilation. A comparison with histamine challenge.

We evaluated isocapnic hyperventilation with room temperature gas (IHV) as a test of bronchial hyperreactivity and compared it with histamine challenge (HC) in three groups of subjects: normal subjects, known mild asthmatic patients, and patients referred to the pulmonary clinic for a chief complaint of dyspnea. Physical examination at the time of evaluation was negative in all subjects. When the criterion for a positive reaction to IHV was a decrease in FEV1 of 10 percent or greater, and the criterion for a positive reaction to HC was a PD20 (concentration of inhaled histamine necessary to decrease FEV1 by at least 20 percent) of less than 10 mg/ml, the specificity of both tests was 100 percent. The sensitivity of both tests as evaluated from the known asthmatic patients was also 100 percent. Among the dyspneic patients, eight of 30 reacted to both IHV and HC, two of 30 reacted to HC alone, and eight of 30 reacted to IHV alone. It was concluded that IHV compares favorably with HC as a test of bronchial hyperreactivity, patients with clinical histories highly suggestive for asthma might not need to undergo bronchial challenge testing, and neither HC nor IHV when used alone is able to identify all of the hyperreactive patients.

Adolescent↗
PubMed1989

Comparison of ultrasonically nebulized distilled water and cold-air hyperventilation challenges in asthmatic patients.

Cold-air hyperventilation (CAHC) and ultrasonically nebulized distilled water (UNDW) challenges were compared in 11 asthmatic patients who were moderately sensitive to methacholine. The challenges were performed on two separate days within one week of each other. Baseline FEV1 on each test day was greater than 70 percent of predicted. Ten of 11 subjects' FEV1 decreased at least 15 percent, and nine of 11 decreased at least 20 percent during the UNDW. Ten of 11 subjects' FEV1 decreased at least 10 percent, and eight of 11 decreased at least 15 percent during the CAHC. Using a Spearman rank coefficient, the results of the CAHC and UNDW were compared; the best correlation between the various CAHC and UNDW measurements equaled only 0.51. The correlation between UNDW and CAHC suggests that the mechanism of action of each challenge may be different.

Adult↗
PubMed1996

Obstruction of ECT seizure by submaximal hyperventilation: a case report.

Extreme obstruction of ECT seizure induction occurred in an elderly female with a low cardiac ejection fraction after a 20 to 25 s interval between the last ventilation and the electrical stimulus. Stimuli of 378 and 504 mC induced no motoric or EEG activity after an initial stimulus of 227 mC produced just 1 s of motoric seizure activity. After prolonged hyperventilation and immediate stimulation a seizure resulted with 33 s of motoric activity. This case suggests that patients with a low cardiac output might be particularly sensitive to the quality of ventilation.

Aged↗
PubMed2001

Comparison of high-frequency flow interruption ventilation and hyperventilation in persistent pulmonary hypertension of the newborn.

INTRODUCTION: Because of the high mortality, potential limitations, and inherent adverse effects associated with conventional therapies, as well as extracorporeal membrane oxygenation, for persistent pulmonary hypertension of the newborn (PPHN), alternative modes of ventilatory support have been researched. There is anecdotal evidence that high-frequency flow interruption ventilation (HFFI) benefits neonates with severe air leak and lung diseases unresponsive to conventional ventilation, so we conducted a study to compare the hospital course, survival rate, and incidence of chronic lung disease of neonates with PPHN treated with hyperventilation (HV) and HFFI. METHODS: Enrolled in the study were 36 neonates who (1) were treated with HV and a fraction of inspired oxygen of 1.0 for PPHN, (2) had arterial partial pressure of oxygen (P(aO2)) values or= 120 mm Hg; (3) shorter mean time to P(aO2) >or= 120 mm Hg (13.5 vs 50.2 h, p = 0.001); (4) shorter mean time to reduced fraction of inspired oxygen (16 vs 84 h, p < 0.001); (5) shorter mean time to fraction of inspired oxygen 0.70 (53 vs 187 h, p < 0.001); (6) shorter mean time to extubation (8.1 vs 18.7 d, p = 0.033); (7) shorter length of hospitalization (22.7 vs 50.6 d, p = 0.025); and (8) fewer neonates with chronic lung disease (1 vs 5, p = 0.018). CONCLUSIONS: HFFI with the ventilation strategy we describe accomplishes sustained hyperoxygenation without hypocarbia and alkalosis, and response to HFFI can predict outcomes. HFFI does not significantly reduce mortality, but it does reduce the length of mechanical ventilation, the length of hospitalization, and the incidence of chronic lung disease in neonates with PPHN. The nonrandomized design of our study precludes firm conclusions about the potential benefits of HFFI. The results may be biased by practice variations. Additional randomized controlled trials are warranted to determine the efficacy of HFFI in neonates with PPHN.

Blood Gas Analysis↗
PubMed2001

Relationship between hyperventilation and intracranial pressure in patients with severe head injury.

With high fatality rate and disability rate, the pathophysiologic changes of severe head injury are complicated. But the method of lowering intracranial pressure (ICP) through artificial hyperventilation is called in question recently. To understand the related changes of the partial pressure of carbon dioxide in artery (PaCO(2)) and the ICP at the acute period of severe head injury, a total of 64 patients with severe head injury were monitored and analyzed on the 3rd day after injury.

Adolescent↗
PubMed1990

[A simple formula for calculating the CO2 flow in controlled hyperventilation of patients with solvent poisoning].

Controlled hyperventilation is a therapeutic measure for the treatment of intoxications with solvents. To avoid the occurrence of respiratory alkalosis, carbon dioxide must be added to the inspiratory gas flow. Up to now the addition of carbon dioxide was performed empirically and was adapted to the needs by repeated blood gas analyses. We developed a formula enabling us to calculate the necessary carbon dioxide flow. A case report explains the procedure.

Adult↗
PubMed1989

A comparison between the airway response to isocapnic hyperventilation and hypertonic saline in subjects with asthma.

We compared the response to isocapnic hyperventilation (ISH), where both cooling and drying of the mucosa occur, with the response to inhaling aerosols of hypertonic saline (HS), where airway osmolarity increases without airway cooling. We studied nine subjects on two days. For ISH, subjects ventilated at 70% of their estimated maximum voluntary ventilation (MVV). For HS, they inhaled aerosols of 2.7, 3.6, or 4.5% saline. The concentration that was used depended on the rate of ventilation during ISH. For both challenges the stimulus was given for one minute. Forced expiratory volume in one second (FEV1) was measured once between each minute, and the challenge ceased when the FEV1 did not change for two successive minutes. A plateau in FEV1 occurred after 8.1 +/- 2.4 (mean +/- 1 SD) min of ISH, and 8.3 +/- 2.4 min of HS. The lowest FEV1 (% predicted) after ISH was 45 +/- 16% and after HS was 51 +/- 18% (r = 0.93). However, the maximum responses occurred after the final challenge and were not the same as the plateau. For HS, the plateau represented 89 +/- 11% of the maximum response which developed within one minute of the final challenge. For ISH, the plateau was only 56 +/- 26% of the maximum response, which developed within 5.2 +/- 2.9 min after challenge. The similarities in the response to these challenges are consistent with the hypothesis that ISH induces asthma via hyperosmolarity. The delayed response to ISH suggests that cooling may delay the response to hyperosmolarity.

Adolescent↗
PubMed1988

[Detection of bronchial hyperreactivity especially in exercise asthma using cold air hyperventilation provocation, free walking and acetylcholine].

In 92 children with different severity of bronchial asthma, a provocation by hyperventilation with cold air has been performed. Forty seven percent of the patients reacted with significant changes of RvD, of RoS, and of FEV1. All patients with negative response to cold air (53%) showed a significant increase of Ros after the inhalation of acetylcholine (threshold value: less than or equal to 0.1%). Eighty percent of the examined asthmatics with negative reaction to cold air reacted after free running with a significant increase of Ros. Thus, the hyperreactivity to a stress by cold air was no general or regular phenomenon in the patients with bronchial asthma investigated by us. There was also no correlation between complaints triggered by exercise reported in the anamnesis, the results of provocation tests using cold air, and the results of respiratory function test after free running.

Acetylcholine↗
PubMed1986

Paroxysmal hyperventilation responses in the adult electroencephalogram.

Hyperventilation (HV) is an important activating procedure in clinical EEG. Paroxysmal HV slowing is associated with hypoglycemia and is common in children. Paroxysmal slowing in adults is sometimes interpreted as indicating cerebral instability or paroxysmal tendencies. We investigated the clinical correlates of paroxysmal HV slowing in 100 consecutive EEGs recorded in 1984 and compared these to 100 controls (age-matched normal EEGs recorded since 1982). Twenty-eight percent of patients over 15 with paroxysmal HV slowing not due to hypoglycemia had headaches, 80% of them vascular. Ten percent had syncope, 15% acute behavioral changes possibly representing seizures, 9% psychiatric disorders, 5% assorted complaints of obscure etiology, 20% had clinically definite seizures, 10% assorted neurologic disorders other than epilepsy, and 3% mental retardation. Fewer patients with HV paroxysms had epilepsy than did control individuals (p less than 0.05), while neurologic disorders of other kinds were more often found in those with HV paroxysms (p less than 0.025). Specific psychiatric diagnoses were less frequent in the paroxysmal HV group, but the difference was not significant. Paroxysmal HV responses in non-hypoglycemic adults may identify individuals prone to syncope, vascular headaches, or other autonomic dysfunction. They are not correlated with epilepsy however, and should not be considered abnormal.

Adult↗
PubMed1986

[Use of the hyperventilation test in patients with various forms of angina].

The pulmonary hyperventilation (HV) test was carried out in 31 coronary patients with stable angina and 11 patients with spontaneous (angiospastic) angina. The test results were compared to those obtained with bicycle ergometry (BE), 24-hour ECG monitoring and selective angiography. The HV test was positive in 7 of 24 patients with positive BE results. The BE and 24-hour ECG monitoring were superior to the HV test in terms of sensitivity. Positive HV tests were more common in spontaneous angina. It is suggested that the HV test can be used for diagnosis and medication efficiency control in coronary patients.

Adult↗
PubMed1975

Treatment of comatose patients by mechanical hyperventilation.

In case of cranial trauma, early respiratory troubles either of central or peripheral origin often accelerate the deterioration of the neurological situation. The different values of PCO2, PO2, pH and alcaline reserve measured on samples of CSF in comatose patients prove the central acidosis related to metabolic and vascular disorders in the damaged areas. Our results confirm the correlation between the importance of this disturbances and the severity of the trauma. It is thus necessary to insure patients of satisfactory respiration conditions. The tracheobronchial cleansing is applicable to intubated or tracheotomized patients by an instillation of 5ml of simple or bicarbonated physiological serum 4 to 6 times a day, followed by repeated aspirations and associated to a preventive endotracheal instillation of 80 mg of Gentamycin 4 times a day. Moreover we use controlled respiration which does not modify the gazometric parameters in the CSF but which assures patients a normoxia and moderate hypocapnia with a decrease of intracranial hypertension. Treatment by controlled hyperventilation must be precocious, because the recuperation at the level of the damaged zones is very slow.

Adult↗
PubMed1983

[Effect of therapeutic hyperventilation on blood lactate concentration].

The increase of blood lactate is a well known side effect of active and passive hyperventilation. In 22 patients who underwent controlled respiration after head injury or elective neurosurgical operations, we measured lactate, pyruvate, pH, and bicarbonate in central venous blood and investigated their interference by hypocapnia. The level of ventilation was between pCO2 equal 25 mmHg and pCO2 equal 45 mmHg, measured in the central venous blood. With decreasing pCO2, pH showed an increasing (from 7.40 +/- 0.015 to 7.50 +/- 0.068) and bicarbonate a decreasing tendency (from 25.46 +/- 1.32 mMol/l to 23.28 +/- 3.76 mMol/l). Lactate and pyruvate remained within the normal range down to a central venous pCO2 of 31 mmHg. But then with increasing hypocapnia both increased significantly (lactate 2.001 +/- 1.08 mMol/l, 0.098 +/- 0.068 mMol/l). At a pCO2-range of 25-27 mmHg (central venous) lactate continued increasing to 2.212 +/- 0.995 mMol/l whereas pyruvate dropped to 0.087 +/- 0.05 mMol/l. Therefore the possibility of hypocapnia-induced lacticemia seems to arise at a ventilation level less than 30 mmHg (pCO2 central venous). Production of excess-lactate may begin at a central venous pCO2 of 27 mmHg.

Adult↗
PubMed1984

[Value of isocapnic hyperventilation in measuring bronchial reactivity in the child].

The bronchial reaction to isocapnic hyperpnoea in asthmatic children is described. There were two groups of children, asthmatic and non asthmatic and the following measurements were made: The vital capacity (CV). The maximum forced expired volume in one second FEV1 (VEMS). The airways resistance Raw (RVA). The Maximum expiratory flow at 75% of the VC, MEF75 (V75) before and after hyperventilating for one minute. In asthmatics the test leads to an increase in resistance (RVA) as well as a fall in FEV1 (VEMS) and V75. The fall in expiratory flow produced by isocapnic hyperpnoea is both a simple and a relevant test.

Adolescent↗
PubMed1995

[Clinical significance of diffuse vasoconstriction of coronary arteries--a study using hyperventilation thallium-201 myocardial imaging].

Hyperventilation Thallium-201 imaging was evaluated for the examination of the existence of ischemia in the cases of diffuse vasoconstriction under the ergonovine maleate provocative test for coronary artery. Transient myocardial perfusion defect (PD) was demonstrated in 14 patients with ergonovine induced vasospasm (group S), and 13 of these patients also demonstrated redistribution (RD) (92.4%). In 14 patients with diffuse vasoconstriction (group D), nine demonstrated PD, and all of them revealed RD. On the other hand, only one of ten (10%) patients demonstrated PD and RD in a group of patients without spasm or diffuse vasoconstriction (group N). In addition, the left ventricular myocardium was divided into nine segments on a SPECT image, and the mean minimum washout rate (WOR) of each segment was evaluated. These values were compared with the percent change of the lung/heart ratio between early and delayed images (delta L/H%). Both the mean minimum WOR mean and delta L/H% of group D were significantly smaller than that of group N (p < 0.001), and only approximated to group S. Thus, the possibility of myocardial ischemia of diffuse vasoconstrictive coronary artery is implicated and such patients are supposed to be treated medically as vasospastic angina.

Aged↗
PubMed1997

Effect of inhaled beclomethasone dipropionate on isocapnic hyperventilation with cold air in asthmatics, measured with forced oscillation technique.

Isocapnic hyperventilation with cold air (IHCA) is a reliable technique for assessing indirect bronchial hyperresponsiveness in patients with asthma. Impedance measurement of the respiratory system by the forced pseudorandom noise oscillation technique is a sensitive technique to assess changes in bronchial tone after IHCA. The aim of this study was to evaluate the effect of 6 weeks of treatment with beclomethasone dipropionate, 1,000 microg x day-1, on IHCA in asthmatic patients, measured with both forced oscillation technique and flow-volume recordings. Forty patients with mild asthma were included in this double-blind, placebo-controlled parallel-group study. Stratification on the basis of sex was performed to overcome differences in airway diameter. At entry and every 2 weeks during the treatment period, IHCA was performed and patient diaries were evaluated. Characteristic changes in forced oscillation parameters after IHCA were observed in all patients. After 6 weeks of treatment, BDP-treated patients showed statistically significant differences in impedance measurements after IHCA, manifested by significant attenuation of resistance at 8 Hz (p<0.01), slope of the frequency-resistance curve (p<0.01), reactance at 8 Hz (p=0.01), and resonant frequency (f0) (p<0.02). Flow-volume recordings showed only a statistically significant change in the decrease of inspiratory vital capacity (IVC) (p=0.01). Furthermore, a significant correlation was observed between serum immunoglobulin E (IgE) levels and the effect of BDP on IHCA, measured with forced oscillation technique. In this study, beclomethasone dipropionate, 1,000 microg x day(-1) for 6 weeks, decreased indirect bronchial hyperresponsiveness as assessed by cold air bronchoprovocation in asthmatic patients. The forced oscillation technique proved a more sensitive method of detecting changes in bronchial tone than flow-volume recordings.

Adult↗