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PubMed1981

The clinical outcome of patients with severe head injuries, treated with highdose dexamethasone, hyperventilation and barbiturates.

The outcome in 45 consecutive patients following severe head injuries is presented. All patients were evaluated according to the Glasgow Coma Scale and the Glasgow Outcome Scale. All patients received a combined treatment consisting of dexamethasone, barbiturate and hyperventilation. A primary operative intervention was performed in 14 patients with intracranial haematomas. There was a good recovery in 53%, 20% were moderately disabled, 11% were severely disabled. 16% died or remained in a vegetative state. The patients were aged between 5 and 83 years, 49% were under 20 years, and the relationship between age and outcome was demonstrated. 86% of the patients under 20 years and 60% over 20 years made a good recovery. These results indicate that a more favourable prognosis is possible after severe head injury, especially in children and thus the combined treatment described above appears justified.

Adolescent↗
PubMed1991

Group treatment of the hyperventilation syndrome.

Hyperventilation (hv) is increasingly recognized as being significant in a number of psychological and medical conditions. The core of treatment for hv is breathing retraining, usually on an individual basis. This article describes a group therapy for breathing retraining for patients with hv-induced panic reactions. An analysis of group process suggests that such treatment is helpful in ways impossible for individual retraining and that further exploration of this modality is warranted.

Anxiety Disorders↗
PubMed1985

Hyperventilation syndrome. Bridging the behavioral-organic gap.

Hyperventilation syndrome is frustrating to patient and physician alike. This common condition can be managed successfully if the primary care physician understands the pathophysiology of symptoms and takes a persistent, supportive approach to the patient. Invasive testing and psychiatric referral are less effective and more costly than an ongoing relationship with a primary care physician. Positive results are most likely to derive from frequent office visits marked by reassurance and repetition of instructions on how to cope with anxiety and its attendant symptoms.

Adolescent↗
PubMed2003

Hyperventilation response in the electroencephalogram and psychiatric problems in children with primary monosymptomatic nocturnal enuresis.

OBJECTIVES: The aim of this study was to determine the frequency of an increased hyperventilation (HV) response in the electroencephalogram and to compare the results of psychometric assessments and electroencephalography (EEG) patterns in children with and without primary monosymptomatic nocturnal enuresis and in dry siblings of enuretics. We also compared the results of psychometric assessments and EEG patterns between enuretic and non-enuretic children. MATERIAL AND METHODS: The study included 89 children divided into three groups: 41 with primary monosymptomatic nocturnal enuresis, their 29 dry siblings and 19 with no history of voiding dysfunction (controls). Resting EEG changes were evaluated in all children. In addition to a psychiatric evaluation, the Maudsley Obsessive Compulsive Questionnaire, the Beck Child Depression Inventory and the State and Trait Anxiety Inventory for Children were used to assess obsessive-compulsive disorder, depression and anxiety, respectively. RESULTS: The time at which real words were first spoken occurred significantly later in enuretic children (p<0.01). The frequency of EEG abnormalities was significantly higher in the enuresis group and in their dry siblings than in the control group (p<0.01). Additionally, as an indicator of cortical dysmaturity, an increased HV response was observed more often in enuretic children and their dry siblings than in the control group (p<0.001). Anxiety scores for the enuretic children were higher than those for the controls (p<0.01). There was no significant difference in psychiatric problems between the enuresis and control groups (p>0.05). CONCLUSIONS: The increased frequency of a high-level HV response in resting-state EEG recordings and the anxiety scores suggested that delayed cortical maturity and high anxiety may be important factors in the pathogenesis of primary monosymptomatic nocturnal enuresis. The HV responses in the dry siblings of the enuretic children may emphasize the relationship between insufficient cerebral maturation and the genetic origin of nocturnal enuresis.

Adolescent↗
PubMed2002

Genital and subjective sexual arousal in postmenopausal women: influence of laboratory-induced hyperventilation.

The current study was aimed at comparing genital and subjective sexual arousal in pre- and postmenopausal women and exploring the effects of heightened sympathetic nervous system (SNS) activity on these parameters. Seventy-one women (25 young and premenopausal, 25 postmenopausal, and 21 age-matched premenopausal women) participated in two counterbalanced sessions consisting of genital arousal assessment with vaginal photoplethysmography and subjective arousal assessment with self-report questionnaires. SNS activity was enhanced using laboratory-induced hyperventilation. Results demonstrated no significant differences between pre- and postmenopausal women on genital and subjective measures of arousal in response to neutral and erotic films. SNS manipulation increased genital excitement only in young, premenopausal women. These data suggest that prior SNS enhancement can differentiate pre- from postmenopausal genital arousal. Data also revealed significant correlations between genital and subjective sexual arousal in older pre- and postmenopausal women, but not in young premenopausal women. These data are the first to directly compare genital-subjective correlations between pre- and postmenopausal women.

Adult↗
PubMedDate not supplied

Impulse oscillometry is sensitive to bronchoconstriction after eucapnic voluntary hyperventilation or exercise.

Airway responses were compared following 6-minute eucapnic voluntary hyperventilation and 6-minute exercise challenges by examining resting and post-challenge impulse oscillometry and spirometry variables. Twenty-two physically active individuals with probable exercise-induced bronchoconstriction took part in this study. Impulse oscillometry and spirometry were performed at baseline and for 20 minutes post-challenge at 5-minute intervals. High correlation was found between the two measures of change in airway function for both methods of challenge. Impulse oscillometry detected a difference in degree of response to the challenges, whereas spirometry indicated no difference, suggesting that impulse oscillometry is a more sensitive measure of change in airway function.

Adolescent↗
PubMed2004

An evaluation of standardizing target ventilation for eucapnic voluntary hyperventilation using FEV1.

Athletes are required to provide objective documentation of exercise-induced bronchoconstriction (EIB) to use beta2-agonists during Olympic competition. A positive response to bronchial provocation by eucapnic voluntary hyperventilation (EVH) is considered acceptable confirmation of EIB. Thirty times forced expiratory volume in the first second (FEV1) is recommended as EVH target ventilation (TV), an intensity intended to estimate 85% of maximal voluntary ventilation (MVV). There is a paucity of data examining the accuracy of predicting MVV from FEV1 in elite athletes. The purpose of this study was to evaluate the efficacy of 30 x FEV1 as standardized EVH TV. Maximal minute ventilation during exercise (VEmax) and pulmonary function of 78 elite winter athletes (25 males, 53 females; 25 EIB positive, 53 normal) were analyzed retrospectively. Adequacy and variability of the equation was ascertained by examining the ratio of EVH TV (30 x FEV1) to VEmax. VEmax was 99+/-11% of predicted MVV (35 x FEV1) and was positively related (r=0.85, p < or = 0.05). TV was 88+/-9% of VEmax (range: 64-109). For elite athletes, the high variability in 30 x FEV1 to standardize TV for EVH may result in under-diagnosis for low-end outliers. Since VEmax of elite endurance athletes is typically known (via maximal aerobic testing) we recommend 85% VEmax as a more accurate and reliable method to establish EVH TV for this group; if VEmax is not available, then 85% of measured MVV may be used.

Adult↗
PubMed1989

Pharmacokinetics of sufentanil in neurosurgical patients undergoing hyperventilation.

The pharmacokinetics of sufentanil were determined in 11 hypocapnic (arterial PCO2 2.9-3.7 kPa) and seven normocapnic (arterial PCO2 5.3-6.0 kPa) neurosurgical patients. Following a single i.v. bolus of sufentanil 4 micrograms kg-1, multiple arterial samples were obtained at timed intervals and plasma concentration of sufentanil was measured by radioimmunoassay. Calculation of the pharmacokinetic parameters from the derived compartmental models demonstrated an increased total volume of distribution of sufentanil in hypocapnic patients (mean 5427 (SD 1866) ml kg-1 v. 3518 (1097) ml kg-1; P less than 0.05) in the control patients and a more prolonged elimination half-life (232 (60) min v. 143 (51) min; P less than 0.01). The increased distribution of sufentanil with hyperventilation was probably caused by an increased proportion of opioid in the nonionized state.

Adult↗
PubMed1996

Slow ventilatory dynamics after isocapnic hypoxia and voluntary hyperventilation in humans: effects of isoflurane.

Short-term potentiation (STP) of breathing refers to respiratory activity that persists at termination of a primary stimulus and is not related just to the dynamics of chemoreceptors. In humans, STP is activated by brief episodes of hypoxia and voluntary hyperventilation (VHV). STP exerts a stabilizing influence on breathing pattern. To investigate the effects of a subanaesthetic concentration of isoflurane on STP, we studied recovery from mild and moderate hypoxic hyperpnoea and VHV. Experiments were performed in eight healthy volunteers. If necessary, subjects were aroused to maintain a state of wakefulness. In the hypoxic studies, a control study involved 1 min of isocapnic hypoxia (end-tidal PO2 (PE'O2 6.1) kPa) followed by sudden transition to normoxia. In the isoflurane studies, 1 min of mild hypoxia (Iso-1 study: PE'O2 6.2 kPa) and 1 min of moderate hypoxia (Iso-2 study: PE'O2 5.7 kPa) were followed by sudden transition to normoxia during inhalation of 0.1 minimum alveolar concentration (MAC) of isoflurane. PE'CO2 was maintained at 5.9 kPa. In the VHV study, ventilatory recovery from 1 min of normoxic VHV was monitored before and during inhalation of 0.1 MAC of isoflurane. Subjects performed multiple transitions in each study. In the hypoxic studies, peak ventilation after 1 min of hypoxic stimulation did not differ between treatments. The averaged responses reached normoxic baseline after 56.3 (SEM 10.7) s in the control study (n = 47 transitions), 18.0 (3.3) s in the Iso-1 study (n = 41; P < 0.05 vs control) and 15.3 (2.4) s in the Iso-2 study (n = 23; P < 0.05 vs control). In the VHV studies, VE at termination of VHV was not different from baseline after 36 s in the control study. An immediate reduction to less than baseline ventilation, lasting 24 s, was present in the isoflurane study. We believe that shortening of the time required to reach baseline in the hypoxic studies, and hypoventilation at cessation of VHV in the isoflurane studies, are related to the inability to activate STP of breathing via an effect of isoflurane on respiratory neurones in the brain stem. Increasing the stimulus intensity during isoflurane inhalation (Iso-2 study) did not (re)-activate STP.

Adult↗
PubMed1989

Hyperventilation and ergonovine tests in Prinzmetal's variant angina: comparative sensitivity and relation with the activity of the disease.

Hyperventilation (HV) and ergonovine (E) tests were carried out in a group of 32 patients with variant angina to compare their sensitivity and to correlate the results with the activity of the disease. The HV test was positive in 84% of the patients and E in 94% of them; the percentage of positive responses to HV was similar to that to E (96% vs 100%) in the patients with daily attacks, while it was lower (55% vs 77%) in those with sporadic attacks. All 27 patients with a positive HV also had a positive response to E, while of the five patients with a negative HV, two also had a negative response to E and the other three had a positive E at a higher dose than that of the patients with daily attacks. The incidence of chest pain and of ST-segment elevation or depression or T-wave positivization was similar during the two tests; however, spontaneous remission of ischaemia was more frequent after HV than after E and ventricular arrhythmias less frequent during the HV test. At the onset of myocardial ischaemia pH was significantly higher compared with basal values (7.51 +/- 0.07 vs 7.38 +/- 0.05, P less than 0.001), while double product was not significantly different compared with basal (10.0 +/- 2.4 vs 9.2 +/- 2.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris, Variant↗
PubMed1984

Prevalence of vasospastic ischaemia induced by the cold pressor test or hyperventilation in patients with severe angina.

We performed coronary artery spasm provocation, using the cold pressor test (CPT) and hyperventilation (HVT) in 105 patients (87 males, 18 females) with mean age 51.9 years (range 25-69) consecutively admitted for coronary angiography due to attacks of chest pain. A positive response to spasm provocation (ST segment elevation or depression greater than or equal to 0.1 mV or pseudonormalization of negative T-waves) was seen in 25 patients (23.9%) (group A), with 8 patients responding to CPT and 23 to HVT. In the remaining patients (group B) a negative response was found. Of 80 patients with coronary artery stenosis (diameter reduction greater than 50%), 22 (27.5%) showed a positive response. During CPT and HVT the rate pressure product increased 25% and 16%, respectively in group A versus an increase of 139% during exercise testing in the same patients. This suggests that ischaemia induced by CPT or HVT is not caused by increased myocardial oxygen demand. Repeat spasm provocation was performed during coronary angiography in 14 patients from group A and 14 from group B. The induced reduction in the diameters of the ischaemia related vessels was on average 48.3% in group A versus a 9.9% reduction of the left anterior descending artery in the patients from group B (P less than 0.01). In group A 88% had a history of nocturnal angina versus 38.8% in group B (P less than 0.001). A positive exercise test was found in 87% and 35.6% in group's A and B respectively (P less than 0.0005).

Adult↗
PubMed1997

Hypoxaemia in patients with hyperventilation syndrome.

We assessed 12 patients with hyperventilation syndrome (HVS) who had experienced hypoxaemia (PaO2 < 60 Torr or SaO2 < 90%) despite the lack of any other organic disease and variability in their blood gas data. Hypoxic and hypercapnic ventilatory responses were measured in nine. Eight of the 12 patients had been referred from other hospitals to our institution for hypoxaemia of unknown origin. Mean PaO2 (n = 12) at rest (non-attack stage) was 87.3 +/- 7.5 Torr (mean +/- SD). Their (n = 9) hypoxic (-0.53 +/- 0.32 l/min/%; range 0.12-0.99) and hypercapnic (2.01 +/- 0.76 l/min/Torr; range 0.69-3.17) ventilatory responses were both within the normal range in our laboratory. The patients with HVS had variable blood gas data, and some of them also exhibited hypercapnia (PaCO2 > 45 Torr). Clinicians who treat patients with HVS should be aware of the possibility of hypoxaemia, even when ventilatory responses are normal. Physicians should also consider HVS as a diagnosis when treating patients with hypoxaemia of unknown origin.

Adult↗
PubMed1975

Physiologic effects of transfusing red blood cells with high or low affinity for oxygen to passively hyperventilated, anemic baboons: systemic and cerebral oxygen extraction.

Anemic, passively hyperventilated baboons were given preserved red blood cells either with increased or with slightly reduced affinity for oxygen to restore the red cell volume. In the high affinity group there was a 50% increase in cerebral blood flow immediately after the transfusion, but there was no significant change in the low affinity group. The cardiac output decreased slightly in the low affinity group, and increased slightly but insignificantly in the high affinity group. Two hours after transfusion the cerebral blood flow had returned to normal in the high affinity group. In both groups there was a decrease in arterial blood pH and an increase in Po2 in blood from the pulmonary artery and the jugular vein after transfusion. A 40% restoration of the 2,3 DPG level occurred within 4 hours of the transfusion of red cells with high affinity for oxygen, and this rapid increase was associated with increases in blood pH and inorganic phosphorus levels. Preserved red cells with high affinity for oxygen and low 2, 3 DPG levels significantly increased the cerebral circulation during the 2-hour posttransfusion period. These findings lend support to the recommendation that preserved red cells with normal or elevated 2,3 DPG levels be administered to patients in hemorrhagic or septic shock, and to patients subjected to extracorporeal circulation during cardiac surgery in order to lessen the demand for increased blood flow and to ensure adequate tissue oxygenation during the postoperative period.

Anemia↗
PubMed1989

Effects of hyperventilation, hypothermia, and altered blood viscosity on cerebral blood flow, cross-brain oxygen extraction, and cerebral metabolic rate for oxygen in cats.

Therapies including hyperventilation (HV) and hypothermia (HT) are currently simultaneously used in brain-injured children at risk for cerebral swelling to reduce cerebral blood flow (CBF) and alter cerebral metabolic rate for oxygen (CMRO2). Since HV and HT may contribute to significant patient morbidity, we evaluated the effects of these treatments in combination on CBF, CMRO2, and cross-brain oxygen extraction (CBO2) using the Kety-Schmidt technique before controlled bleeding to alter blood viscosity in 20 lightly anesthetized, paralyzed cats, and after bleeding in another 17 cats. The degree of HV (PaCO2 24 to 26 torr) and HT (32 degrees and 30 degrees C) used were representative of that employed in pediatric neurointensive care. HV at normothermia resulted in a significant decline in CBF (P less than .05) and an unchanged CMRO2. HV and HT together to 32 degrees C resulted in a further significant fall in CBF and CMRO2 (p less than .05), but an unchanged CBO2. Further cooling of the animal to 30 degrees C during HV, both before and after controlled bleeding, resulted in no further significant fall in CBF, CBO2, or CMRO2. This relationship was found despite a significant fall in Hgb (p less than .001), suggesting that blood viscosity did not significantly influence CBF at this temperature. Our data suggest that HT to 32 degrees C during HV may have therapeutic benefit by decreasing CBF and CMRO2, but further cooling to 30 degrees C may not result in further cerebral protective effects.

Animals↗
PubMed1993

Hyperventilation and transcranial magnetic stimulation: two methods of activation of epileptiform EEG activity in comparison.

In a prospective study, we compared the established method for an activation of epileptiform activity in EEG, hyperventilation (HV), with the recently presented new activational technique of transcranial magnetic stimulation (TMS) in 10 patients with drug-resistant partial epilepsies. Long-term EEG recordings included subdural electrodes in the course of presurgical evaluation. Epileptiform activity was evaluated visually 500 s before, during, and 500 s after stimulation, and the results were compared statistically. TMS was not better than HV: HV caused an activation of the epileptogenic foci in 6 of 10 cases, TMS only in 3 of 10. Seizures could be induced by HV in 2 of 10, by TMS in no cases. In 2 of 10 cases, TMS even caused a significant reduction of epileptiform activity.

Adolescent↗
PubMed1994

Effects of routine hyperventilation on PCO2 and PO2 in normal subjects: implications for EEG interpretations.

There are few data in the EEG literature describing the time course of hyperventilation-(HV) induced changes in blood gases, despite this being a routine activating procedure. We studied changes in blood gases and EEG in nine normal adult subjects before, during, and after HV. The mean PCO2 fell 18 mm Hg from the baseline during HV and recovered in 7 min. The mean PO2 rose 7 mmHg during HV and fell to 25 mm Hg below baseline 5 min after HV. The PCO2 recovery period is longer than is usually assumed in clinical EEG. The PO2 fall to a nadir at 5 min after the end of HV suggests that close attention should be paid to this period, as is confirmed by the re-buildup seen in moyamoya disease. Despite uniform changes in blood gases, the EEG median power frequency change showed marked variability; on average, it dropped by 1 Hz during HV and returned to baseline within 2 min of resumption of normal respiration. The EEG root-mean-square power showed a 200% increase during HV and also had returned to normal within 2 min.

Adolescent↗
PubMed1995

Effect of hyperventilation, mannitol, and ventriculostomy drainage on cerebral blood flow after head injury.

Therapies to lower intracranial pressure (ICP) after traumatic brain injury (TBI) include hyperventilation (HV), intravenous mannitol (IM), and cerebrospinal fluid drainage from a ventriculostomy (DV). To determine the effects of these therapies on cerebral blood flow (CBF), fiberoptic oximetry was used to measure jugular venous O2 saturation (SjvO2) as an index of the CBF to cerebral metabolic rate for O2 (CMRO2) ratio after IM (25 g IV for more than 5 min), DV (3 min), or HV (increase respiratory rate by 4) therapy for elevated ICP. Assuming CMRO2 is constant, changes in SjvO2 reflect changes in CBF. Continuous measurements of SjvO2, ICP, blood pressure, arterial O2 saturation, and end-tidal CO2 were obtained in 22 patients with a Glasgow Coma Scale score of 5.3 +/- 0.4 (mean +/- SD) in the first 5 days after TBI. Therapy was initiated a total of 196 times when ICP was > 15 mm Hg for > 5 minutes, and measurements made at 20 minutes after treatment were compared with those made just before. After DV, ICP fell in 90% of the observations by 8.6 +/- 0.7 mm Hg (mean +/- SEM, n = 119); after IM, ICP fell in 90% of the observations by 7.4 +/- 0.7 mm Hg (n = 43); and after HV, ICP fell in 88% of the observations by 6.3 +/- 1.2 mm Hg (n = 14). In patients where ICP fell, SjvO2 increased by 2.49 +/- 0.7% saturation (from 68.0 +/- 1.3%) with IM, but only by 0.39 +/- 0.4% saturation (from 67.2 +/- 0.9%) with DV.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗