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At least 775 records · Page 43Linked to original sources
PubMed1992

[Efficacy of succinylcholine under hyperventilation].

To evaluate hypocapnic effect on muscle relaxant, we investigated succinylcholine under normal condition (PetCO2 5-5.5kPa) and hyperventilation (PetCO2 3-3.5kPa), with the patients as the self control. Fifteen patients undergoing selective surgery were divided randomly into two groups. The hypocapnic effect on single intubational dose course as well as sustaining two hours was observed with the neuromuscular blockade traced by accelograph. The results showed that the speed of onset, recovery time and duration of succinylcholine after 1 mg/kg i.v. have no significant difference between normal condition and hyperventilation. It is indicated that in good risk adult patients, ventilatory hypocapnia for two hours causes no significant change in succinylcholine relaxation.

Adolescent↗
PubMed1985

Nortriptyline-induced severe hyperventilation.

A 61-year-old man with end-stage renal disease developed severe hyperventilation following nortriptyline hydrochloride usage for depression. He required mechanical ventilation and paralysis to correct severe respiratory alkalosis. To our knowledge, nortriptyline usage has not been previously associated with hyperventilation.

Alkalosis, Respiratory↗
PubMed1979

[Effect of artificial hyperventilation of the lungs on acid-base equilibrium and blood and cerebrospinal fluid gases in patients with postoperative psychosis].

The alkaline shift of blood Ph together with marked metabolic acidosis in the liquor were found postoperativery in 42 patients operated upon the colon and small intestine at the height of postoperative psychosis. The patients developed tachipnoe up to 32-36 per minute, followed with a great energy expenditure. As a consequence, artificial pulmonary ventilation (APV) at the hyperventilation regime was administered to a part of the patients to correct acidosis of the liquor. Postoperative psychotic patients need an early administration of the APV at the hyperventilation regime, which is one of effective methods of correcting liquor acidosis in the complex therapy of psychoses.

Acid-Base Equilibrium↗
PubMed1983

[Efficacy of respiratory therapy/controlled hyperventilation in cerebral trauma].

In a prospective study in 129 patients with isolated head injury the efficacy of respiratory treatment/controlled moderate hyperventilation on the neurological outcome is to be tested. Indications for mechanical ventilation are either a bad neurological behaviour (GCS less than or equal to 5) or neurogenic-induced disturbances of pulmonary gas exchange. Both oxygenation and neurological behaviour are worse in the ventilated group than in patients breathing spontaneously. Therefore a direct and quantitative comparison between these two groups of patients is not possible; however, conclusions can be drawn on the efficacy of the respiratory management. Survival rate of all patients on discharge from ICU amounts to 61.2%; of the patients breathing spontaneously 96.1% survive the cerebral trauma, while only 39.7% of the ventilated patients survive. The post-traumatic course of the GCS-values shows a transient but statistically and clinically significant decrease for the nonventilated survivors, while a continuous increase can be demonstrated for the patients being ventilated and surviving the cerebral trauma (n = 31). The survival rate for the most severely injured and ventilated group (n =59; GCS less than or equal to 5) amounts to 38.9% (23/59 patients). Out of these 23 patients with initial extensor spasm 15 reach greater than or equal to 10 points on GCS-scale (12.2 +/- 0.5 P.) on discharge from ICU. An additional neurogenic-initiated respiratory failure increases the rate of mortality to a statistically significant extent (P less than 0.025). It is concluded that respiratory treatment with moderate hyperventilation positively influences the quality of the neurological outcome in patients with severe head injury.

Adult↗
PubMed1984

Effects of hyperventilation on cerebral blood flow and metabolism.

Hyperventilation has been shown to be an effective therapy for PPHN. In this article, cerebral blood flow and its control mechanisms in the fetus and neonate are reviewed and it is concluded that, at present, there is no evidence to suggest that hyperventilation can produce cerebral ischemia.

Adenosine Triphosphate↗
PubMed1981

[Metabolic effects of maternal hyperventilation in obstetrical anaesthesia induction (author's transl)].

Apparative hyperventilation before intubation brings about a favourable blood gas situation, but also a bicarbonate shortage, causing metabolic acidosis with increase of blood lactate and pyruvate. In obstetrics a mother-fetus infusion of lactate can occur, which can produce fetal distress. Because of the relative immaturity of the enzyme systems in the newborn, degradation of the infused lactate proceeds very slowly. These children recover only gradually over a period of several hours. For this reason it appears advisable to hyperventilate only briefly before a quick obstetrical intubation.

Acidosis↗
PubMed1981

Developmental follow-up of hyperventilated neonates: preliminary observations.

A group of 13 newborn infants greater than 37 weeks' gestation were selected to be hyperventilated because of severe hypoxemia refractory to conventional mechanical ventilation, ie, failure to maintain PaO2 greater than 50 torr with an FIO2 of 1.0, despite PaCO2 less than or equal to 40 torr and pH greater than or equal to 7.40. Eleven survived; nine were available for follow-up evaluations. As a group, the nine infants were exposed to a PaCO2 less than or equal to 20 torr for 51.8 +/- 11.8 (mean +/- SEM) hours, to PaCO2 less than or equal to 15 torr for 11.8 +/- 3.3 hours, to a pH greater than 7.50 for 64.4 +/- 18.6 hours, and to a pH greater than or equal to 7.60 for 6.1 +/- 2.9 hours. One infant was lost to follow-up after a normal assessment at nine months. the other eight infants (seven AGA, one markedly SGA) were at least 1 1/4 years old at the time of evaluation. The seven AGA infants had a normal developmental quotient (mean 110 [range 96-130] by Stanford-Binet or Bayley assessment); the one SGA infant had a Bayley score of 89. All eight had normal neurologic examinations. These preliminary findings are reassuring with respect to neurologic and developmental outcome following prolonged hyperventilation.

Child Development↗
PubMed1981

[Effect of hyperventilation on depression of the EEG alpha rhythm caused by a suggested visual image].

An induction of an imagined visual sensation with the eyes closed can be regarded as a form of self-suggestion in the state of wakefulness. On receiving an instruction on imagining a visual sensation most healthy persons show a sharp weakening of disappearance of the alpha-rhythm depression on the EEG (in distinction from subjects who have not had hyperventilation). These findings point to an importance of using electroencephalography in combination with hyperventilation in psychotherapeutic practice for objective estimation of the effect of suggestion in wakefulness.

Adolescent↗
PubMed1994

[The arterial blood gas change in anesthetized patients with apnea: disadvantage of hyperventilation before intubation].

We studied the arterial blood gas changes during 4 minute apnea period without using constant oxygen flow under anesthesia. Fifteen adult surgical patients (ASA PS 1 or 2, 21-49 years of age) were randomly divided into 3 groups by ETCO2 before the start of apnea (group I: 40 mmHg, group II: 30 mmHg, group III: 20 mmHg). In addition, each patient was monitored with pulse oximetry, ECG, blood pressure, FIO2 and ETCO2. The rate of rise of PaCO2 during the apnea showed no significant difference among these 3 groups. In the first minute of apnea, PaCO2 increased 9.8 +/- 1.9 mmHg, and then increased at a rate of 3.4-4.4 mmHg.min-1 thereafter. In conclusion, the rate of rise of PaCO2 in anesthetized patients with apnea was logarithmic and there was no correlation with pre-apnea ETCO2. The rate of SpO2 decrease was significant in hyperventilated group (III). Thus, hyperventilation applied before the endotracheal intubation is not of benefit to the oxygenation of healthy humans.

Adult↗
PubMed1993

[The effects of hyperventilation upon the spinal pain modulating system].

The purpose of this study is to investigate the effects of hyperventilation on the wide dynamic range (WDR) cell of the dorsal horn of the feline lumbar spinal cord. Cats received midcollicular decerebration and lumbar laminectomy. The spinal cord was transected at T12-L1. WDR cells were sampled with microelectrode at the depth of 2,000 microns from the cord dorsum. Following the control period with PaCO2 of 35-45 mmHg, respiratory rate and tidal volume were adjusted to make a level of hypocapnia as low as 20-25 mmHg. The recovery of cell activity was followed when normocapnia was restored. Hypocapnia with PaCO2 of 25-30 mmHg and 20-25 mmHg suppressed the activity of WDR cell significantly. At PaCO2 of 25-30 mmHg, the spontaneous activity was suppressed for about 20% and evoked activity for 27%. At PaCO2 of 20-25 mmHg, the spontaneous activity was suppressed for about 50% and evoked activity for 33%. The results suggest that the hyperventilation has suppressive effects on single-unit activity of WDR cell.

Action Potentials↗
PubMed1993

[Modification of nonspecific bronchial hyperreactivity to cold air hyperventilation and carbachol by nedocromil and budesonide].

In a double blind crossover trial we compared the effect of a four week treatment with inhaled nedocromil (4 x 4 mg/d) or budesonide (2 x 400 micrograms/d by spacer) on non-specific bronchial hyperresponsiveness (BHR) to cold air hyperventilation (CHV) and carbachol. 15 persons with clinically mild asthma, who showed a more than 50% decrease in sG(aw) after CHV were randomly allocated to treatment groups. A double dummy technique was applied. Before and after both treatment periods, which were separated by an out wash period of four weeks, BHR to isocapnic cold air hyperventilation and carbachol was determined on two consecutive days. 13 persons completed the study. Maximum percentual drop of sG(aw-) and FEV1-values after CHV, the number of steps of carbachol-provocation carried out to reach a decrease in sGaw of at least 50% and the calculated cumulative breath units (CBU) of carbachol to cause a 50% (20%) decrease in sG(aw) (FEV1) were assessed. Peak-flow values were registered throughout the study. Data were compared by means of Wilcoxon's matched-pairs signed-ranks test. After budesonide most parameter showed a significant decrease of BHR (CHV: sG(aw) p < 0.1; FEV1 p < 0.05; Carbachol: provocation-steps: p < 0.05; CBU: PD50 sG(aw) p < 0.05; PD20 FEV1 p < 0.05). There was no evidence for an influence of nedocromil on BHR (p-values all > 0.2). Comparing both treatments there was a difference in favour of budesonide partly reaching significance at 5% level. Budesonide but not nedocromil treatment showed a significant increase in peak-flow values (morning p < 0.02, evening p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Lactate and hyperventilation substantially attenuate vagal tone in normal volunteers. A possible mechanism of panic provocation?

Many aspects of panic attacks, eg, palpitations, tremor, sweating, and an emotional sense of "fear," have been theorized to arise from sympathetic nervous system activation. However, most studies have not demonstrated clearly increased levels of catecholamines during an attack, which is contrary to this hypothesis. To explore another possible cause for the physiological changes known to occur during a panic attack, we assessed parasympathetic nervous system activity by measuring vagal tone during treatments known to produce panic symptoms: sodium lactate administration and hyperventilation. Our findings showed a marked reduction in vagal tone during both procedures. We postulate that withdrawal of parasympathetic activity may explain some of the physiological changes occurring in panic attacks and be contributing to the origin of panic.

Adult↗
PubMed1984

Cerebral physiological and metabolic effects of hyperventilation in the neonatal dog.

To clarify the changes that occur during marked hypocarbia in the neonate, we measured brain blood flow and metabolite levels after 90 minutes of hyperventilation in neonatal dogs. Brain blood flow decreased significantly in diencephalon, brainstem, and spinal cord but not in cerebral cortex or white matter. There was no substantial change in the electroencephalogram. Lactate concentrations, both in telencephalon and in superior sagittal sinus blood, increased significantly, although there was no alteration in levels of ATP or phosphocreatine. Marked hypocarbia in the neonatal dog produces an elevated brain lactate level that may be related to changes in glycolytic rate rather than to tissue ischemia or hypoxia.

Adenosine Triphosphate↗
PubMed2001

Acute panic inventory symptoms during CO(2) inhalation and room-air hyperventilation among panic disorder patients and normal controls.

There is scant literature on anxiety symptoms induced during respiratory challenges developed to induce panic symptoms and attacks. Here we report on the prevalence of Acute Panic Inventory (API) symptoms during three consecutive respiratory challenges to patients with panic disorder (PD) and normal controls (NC). The challenges performed using a closed canopy system included voluntary room air hyperventilation (RAH), inhalation of 5% CO(2), and 7% CO(2)-enriched air. The PD patients were 41 men and 53 women whose mean age was 33.4 (SD = 8.55). The normal comparison group consisted of 35 men and 27 women with a mean age of 31.3 (SD = 9.21). The diagnosis of panic disorder was made using the Structured Clinical Interview for DSM-III-R. All potential normal controls underwent structured clinical interview using the Schedule for Affective Disorders and Schizophrenia-Lifetime Version Modified for the Study of Anxiety Disorders (SADS-LA), and must have been free of a lifetime history of anxiety disorders, affective disorders, substance use disorders, and schizophrenia. All participants also had a complete medical evaluation and were in good health. The experiment consisted of seven experimental epochs: three baseline/recovery periods each followed by a respiratory challenge, and then a final recovery epoch. The API was administered at the end of each epoch. Clinical staff trained and experienced in rating panic attacks rated participants' response during each challenge as panic or no panic. Three groups were defined for analysis: PD patients who panicked, PD patients who did not panic, and NC who did not panic. Staff ratings indicated that the 7% CO(2) challenge was the most panicogenic, followed by the 5% CO(2), and the RAH challenges. Conventional statistics (analysis of variance and partial correlations) indicated that many baseline symptoms as well as symptom increments differed across groups, and were associated with the outcome of panic/no panic during each challenge. However, logistic regression analysis indicated that only a few symptoms independently predicted the panic/no panic outcome because many symptoms were redundant. The symptom cluster of fear in general, dizziness, difficulties with concentrating, and doing one's job predicted panic to RAH. The cluster of fear in general, confusion, dyspnea, and twitching/trembling predicted the response to 5% CO(2). Finally, fear in general, confusion, twitching/ trembling and dizziness predicted the response to 7% CO(2). While univariate analyses indicated that many symptoms distinguished between panic and no panic outcome, logistic regression revealed that group differences were subsumed under a few prominent symptoms, namely, fear in general, confusion, dizziness, twitching/trembling, and dyspnea. The results are discussed in the context of patient (having a diagnosis of PD) and panic effects (rated as panicking to a challenge).

Acute Disease↗
PubMed2002

Regional differences of fMR signal changes induced by hyperventilation: comparison between SE-EPI and GE-EPI at 3-T.

PURPOSE: To evaluate whether reproducible signal change of brain tissues by hyperventilation (HV) can be seen on spin-echo (SE)-echo planar imaging (EPI) at 3-T and to examine the sensitivity of SE-EPI for measuring vascular reactivity in regions of the brain, such as the hippocampal formation, that are difficult to visualize with gradient-echo (GE)-EPI due to susceptibility artifacts. MATERIALS AND METHODS: Six healthy human subjects performed a voluntary HV task. The task design was as follows: two minutes normal breathing (rest) followed by two minutes HV, giving a basic four-minute block that was repeated three times for a total scan time of 12 minutes for one run. Each subject performed the run both for SE-EPI and GE-EPI. Statistical analysis was performed to detect the area with significant cerebrovascular reactivity. The percentage signal change was also obtained for each cerebral region. RESULTS: Both GE-EPI and SE-EPI showed globally significant signal decreases in the cerebral cortex. In GE-EPI, the frontal cortex showed a larger signal decrease than the other gray matter tissues (P < 0.05). In SE-EPI, the differences among gray matter tissues except for the hippocampal formation were not significant. The hippocampal formation showed the largest signal change (P < 0.05) in SE-EPI, but no significant signal change was observed in GE-EPI due to the presence of susceptibility artifacts. CONCLUSION: HV using SE-EPI at 3-T provides robust and reproducible signal decreases and may make the evaluation of the vascular reactivity in hippocampal formation feasible.

Adult↗
PubMedDate not supplied

Normocarbic hyperventilation fails to induce pulmonary vasodilation.

The pulmonary vasodilator effect of increased rate of mechanical ventilation, with and without respiratory alkalosis, was studied in chronically instrumented newborn lambs. Pulmonary hypertension was first induced by ventilating with a hypoxic gas mixture. Subsequent respiratory alkalosis caused significant decreases in pulmonary arterial pressure and pulmonary vascular resistance. When normocarbia was re-established by adding carbon dioxide to the inspired gas, with the ventilator rate being held constant, the pressure and resistance returned to the baseline hypertensive state. Therefore, mechanical factors, either direct or indirect, appear to be of minor importance in the mechanism of pulmonary vasodilation secondary to frequency-induced hyperventilation.

Alkalosis, Respiratory↗
PubMed1998

Dose-dependent effects of Cerebrolysin on EEG and short-term memory of healthy volunteers during control and hyperventilation induced cerebral ischemia.

Cerebrolysin, a peptidergic nootropic drug, was to be effective on learning and other cognitive functions in animal experiments as well as in clinical studies. Hyperventilation (HV) as a model of brain ischemia induces slowing of the EEG and cognitive impairment. The aim of this study was to examine the potential dose-dependent effects of Cerebrolysin on HV related EEG changes and short term memory during chronic (10 days) application and the time dependency of these effects. In this single centre, double blind, randomized, placebo-controlled, parallel group study 48 healthy males were enrolled and received either 100 ml placebo (NaCl) or Cerebrolysin (10 ml or 30 ml or 50 ml) in a volume of 100 ml (NaCl) for 10 days. EEG at baseline and during HV as well as the cognitive performance was evaluated at Day 1 (baseline, 15 min p.i., 2 h p.i., 4 h p.i., 8 h p.i., 24 h p.i.), Day 10 (baseline, 15 min p.i., 2 h p.i.,) and at day 11 (24 h. after the last infusion). The main effects found during the study can be summarized as follows: At baseline we found an increase of the EEG power ratio (PR) for the grouptrated with 10 ml Cerebrolysin. The effect was most pronounced at the parietal cortex. The effect started after 15 min, was most expressed at 2 h and was kept until 8 h. During HV we found a relative PR decrease of the group (10 ml Cerebrolysin) at 2 hours. For short term memory, there is a trend towards less effective word recall for the baseline situation during the first 4 hours for the placebo. This effect was not observed in the Cerebrolysin treated groups. If chronic effects are concerned, the PR increased over the parietal regions at 24 h for the groups treated with 10 and 30 ml Cerebrolysin. The effect remains at day 10 and 11. But at 10 and 11 days there was also a trend for a relative increase of the PR in the group treated with 50ml Cerebrolysin. Signs of overdosage occurred with the highest concentrations of Cerebrolysin. The events were only mild and caused no harm to the volunteers. The highest concentration caused a small but significant reduction of blood pressure. The effects could be interpreted as those of an atypical nootropic with anti-ischemic properties.

Adult↗
PubMed2002

Optimizing cerebral perfusion pressure during fiberoptic bronchoscopy in severe head injury: effect of hyperventilation.

The aim of this study was to evaluate if Hyperventilation (HV) could avoid the Intracranial Pressure (ICP) peak that occurs during Fiberoptic Bronchoscopy (FB) in severely head injured patients. A Cerebral Perfusion Pressure (CPP) > 75 mmHg was maintained in 34 patients, with a subgroup randomized to receive controlled HV during FB. Measurements were done before the procedure, during maximum ICP values and 30 minutes after FB. The HV group had minor ICP values after FB, without differences in CPP and ICP peak values.

Adult↗