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Query: UMLS:C0020175 (hunger)
 5,670 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhaled morphine has been used to treat dyspnea in a variety of clinical settings. There are, however, no reports of its use in treating patients with end-stage lung disease due to cystic fibrosis (CF). We report on the use of inhaled morphine sulfate in a 13-year-old boy with CF, advanced lung disease, and acute respiratory failure. Therapy was effective in reducing his subjective feeling of air hunger and improving his BORG score. His sole significant adverse effect was headache after 2 days of treatment at 4-hourly intervals.
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PMID:Inhaled morphine to relieve dyspnea in advanced cystic fibrosis lung disease. 1097 44

Dyspnea in patients could arise from both an urge to breathe and increased effort of breathing. Two qualitatively different sensations, "air hunger" and "respiratory work and effort," arising from different afferent sources are hypothesized. In the laboratory, breathing below the spontaneous level may produce an uncomfortable sensation of air hunger, and breathing above it a sensation of work or effort. Measurement of a single sensory dimension cannot distinguish these as separate sensations; we therefore measured two sensory dimensions and attempted to vary them independently. In five normal subjects we obtained simultaneous ratings of air hunger and of work and effort while independently varying PCO(2) or the level of targeted voluntary breathing. We found a difference in response to the two stimulus dimensions: air hunger ratings changed more steeply when PCO(2) was altered and ventilation was constant; work or effort ratings changed more steeply when ventilation was altered and PCO(2) was constant. We conclude that "air hunger" is qualitatively different from "work and effort" and arises from different afferent sources.
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PMID:The perception of respiratory work and effort can be independent of the perception of air hunger. 1106 98

There are defined medullary, mesencephalic, hypothalamic, and thalamic functions in regulation of respiration, but knowledge of cortical control and the elements subserving the consciousness of breathlessness and air hunger is limited. In nine young adults, air hunger was produced acutely by CO(2) inhalation. Comparisons were made with inhalation of a N(2)/O(2) gas mixture with the same apparatus, and also with paced breathing, and with eyes closed rest. A network of activations in pons, midbrain (mesencephalic tegmentum, parabrachial nucleus, and periaqueductal gray), hypothalamus, limbic and paralimbic areas (amygdala and periamygdalar region) cingulate, parahippocampal and fusiform gyrus, and anterior insula were seen along with caudate nuclei and pulvinar activations. Strong deactivations were seen in dorsal cingulate, posterior cingulate, and prefrontal cortex. The striking response of limbic and paralimbic regions points to these structures having a singular role in the affective sequelae entrained by disturbance of basic respiratory control whereby a process of which we are normally unaware becomes a salient element of consciousness. These activations and deactivations include phylogenetically ancient areas of allocortex and transitional cortex that together with the amygdalar/periamygdalar region may subserve functions of emotional representation and regulation of breathing.
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PMID:Neuroimaging of cerebral activations and deactivations associated with hypercapnia and hunger for air. 1117 70

Little is known about the physiological mechanisms subserving the experience of air hunger and the affective control of breathing in humans. Acute hunger for air after inhalation of CO(2) was studied in nine healthy volunteers with positron emission tomography. Subjective breathlessness was manipulated while end-tidal CO(2-) was held constant. Subjects experienced a significantly greater sense of air hunger breathing through a face mask than through a mouthpiece. The statistical contrast between the two conditions delineated a distributed network of primarily limbic/paralimbic brain regions, including multiple foci in dorsal anterior and middle cingulate gyrus, insula/claustrum, amygdala/periamygdala, lingual and middle temporal gyrus, hypothalamus, pulvinar, and midbrain. This pattern of activations was confirmed by a correlational analysis with breathlessness ratings. The commonality of regions of mesencephalon, diencephalon and limbic/paralimbic areas involved in primal emotions engendered by the basic vegetative systems including hunger for air, thirst, hunger, pain, micturition, and sleep, is discussed with particular reference to the cingulate gyrus. A theory that the phylogenetic origin of consciousness came from primal emotions engendered by immediate threat to the existence of the organism is discussed along with an alternative hypothesis by Edelman that primary awareness emerged with processes of ongoing perceptual categorization giving rise to a scene [Edelman, G. M. (1992) Bright Air, Brilliant Fire (Penguin, London)].
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PMID:Brain responses associated with consciousness of breathlessness (air hunger). 1117 71

Recent neuroimaging and neurological data implicate cerebellum in nonmotor sensory, cognitive, vegetative, and affective functions. The present study assessed cerebellar responses when the urge to breathe is stimulated by inhaled CO(2). Ventilation changes follow arterial blood partial pressure CO(2) changes sensed by the medullary ventral respiratory group (VRG) and hypothalamus, entraining changes in midbrain, pons, thalamus, limbic, paralimbic, and insular regions. Nearly all these areas are known to connect anatomically with the cerebellum. Using positron emission tomography, we measured regional brain blood flow during acute CO(2)-induced breathlessness in humans. Separable physiological and subjective effects (air hunger) were assessed by comparisons with various respiratory control conditions. The conjoint physiological effects of hypercapnia and the consequent air hunger produced strong bilateral, near-midline activations of the cerebellum in anterior quadrangular, central, and lingula lobules, and in many areas of posterior quadrangular, tonsil, biventer, declive, and inferior semilunar lobules. The primal emotion of air hunger, dissociated from hypercapnia, activated midline regions of the central lobule. The distributed activity across the cerebellum is similar to that for thirst, hunger, and their satiation. Four possible interpretations of cerebellar function(s) here are that: it subserves implicit intentions to access air; it provides predictive internal models about the consequences of CO(2) inhalation; it modulates emotional responses; and that while some cerebellar regions monitor sensory acquisition in the VRG (CO(2) concentration), others influence VRG to adjust respiratory rate to optimize partial pressure CO(2), and others still monitor and optimize the acquisition of other sensory data in service of air hunger aroused vigilance.
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PMID:Neuroimaging evidence implicating cerebellum in the experience of hypercapnia and hunger for air. 1117 72

Air hunger (uncomfortable urge to breathe) is a component of dyspnea (shortness of breath). Three human H(2)(15)O positron emission tomography (PET) studies have identified activation of phylogenetically ancient structures in limbic and paralimbic regions during dyspnea. Other studies have shown activation of these structures during other sensations that alert the organism to urgent homeostatic imbalance: pain, thirst, and hunger for food. We employed blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) to examine activation during air hunger. fMRI conferred several advantages over PET: enhanced signal-to-noise, greater spatial resolution, and lack of ionizing radiation, enabling a greater number of trials in each subject. Six healthy men and women were mechanically ventilated at 12-14 breaths/min. The primary experiment was conducted at mean end-tidal PCO(2) of 41 Torr. Moderate to severe air hunger was evoked during 42-s epochs of lower tidal volume (mean = 0.75 L). Subjects described the sensation as "like breath-hold," "urge to breathe," and "starved for air." In the baseline condition, air hunger was consistently relieved by epochs of higher tidal volume (mean = 1.47 L). A control experiment in the same subjects under a background of mild hypocapnia (mean end-tidal PCO(2) = 33 Torr) employed similar tidal volumes but did not evoke air hunger, controlling for stimulus variables not related to dyspnea. During each experiment, we maintained constant end-tidal PCO(2) and PO(2) to avoid systematic changes in global cerebral blood flow. Whole-brain images were acquired every 5 s (T2*, 56 slices, voxel resolution 3 x 3 x 3 mm). Activations associated with air hunger were determined using voxel-based interaction analysis of covariance that compared data between primary and control experiments (SPM99). We detected activations not seen in the earlier PET study using a similar air hunger stimulus (Banzett et al. 2000). Limbic and paralimbic loci activated in the present study were within anterior insula (seen in all 3 published studies of dyspnea), anterior cingulate, operculum, cerebellum, amygdala, thalamus, and basal ganglia. Elements of frontoparietal attentional networks were also identified. The consistency of anterior insular activation across subjects in this study and across published studies suggests that the insula is essential to dyspnea perception, although present data suggest that the insula acts in concert with a larger neural network.
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PMID:BOLD fMRI identifies limbic, paralimbic, and cerebellar activation during air hunger. 1220 70

The purpose of this study was to evaluate the reliability, content validity, and factor structure of dyspnea sensory quality descriptor ratings in emergency department (ED) patients with exacerbated chronic obstructive pulmonary disease (COPD). During an ED visit 104 patients with COPD rated the intensity of 16 dyspnea sensory quality descriptors (numerical ratings of 0-10) in relation to how they felt when they decided to come to the ED (Decision) and 1 week before the visit. Content validity of 15 descriptors was supported. Factor analysis of Decision ratings resulted in seven descriptors and three factors (alpha=.88; 74% common variance): Smothering/Suffocating/Hunger for air (alpha=.87); Effort/Work (alpha=.87); and Tight/Constricted (alpha=.74). Results indicate that the intensity of sensory quality descriptors can be measured reliably in COPD patients during an exacerbation of COPD. The initial descriptor list of descriptors could be cut by more than half while retaining satisfactory psychometric properties.
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PMID:Psychometric characteristics of dyspnea descriptor ratings in emergency department patients with exacerbated chronic obstructive pulmonary disease. 1222 88

Anecdotal observations suggest that hypoxia does not elicit dyspnea. An opposing view is that any stimulus to medullary respiratory centers generates dyspnea via "corollary discharge" to higher centers; absence of dyspnea during low inspired Po(2) may result from increased ventilation and hypocapnia. We hypothesized that, with fixed ventilation, hypoxia and hypercapnia generate equal dyspnea when matched by ventilatory drive. Steady-state levels of hypoxic normocapnia (end-tidal Po(2) = 60-40 Torr) and hypercapnic hyperoxia (end-tidal Pco(2) = 40-50 Torr) were induced in naive subjects when they were free breathing and during fixed mechanical ventilation. In a separate experiment, normocapnic hypoxia and normoxic hypercapnia, "matched" by ventilation in free-breathing trials, were presented to experienced subjects breathing with constrained rate and tidal volume. "Air hunger" was rated every 30 s on a visual analog scale. Air hunger-Pet(O(2)) curves rose sharply at Pet(O(2)) <50 Torr. Air hunger was not different between matched stimuli (P > 0.05). Hypercapnia had unpleasant nonrespiratory effects but was otherwise perceptually indistinguishable from hypoxia. We conclude that hypoxia and hypercapnia have equal potency for air hunger when matched by ventilatory drive. Air hunger may, therefore, arise via brain stem respiratory drive.
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PMID:Hypoxic and hypercapnic drives to breathe generate equivalent levels of air hunger in humans. 1239 Oct 41

There is a subpopulation of asthmatic patients with a history of life-threatening asthma (LTA) who have a reduced perception of respiratory loads. The aim of this study was to determine if these patients have a reduced perception of both intrinsic and extrinsic loads. Children with asthma were classified into life-threatening asthma and control asthmatic groups. Perception of extrinsic loads was assessed by magnitude estimation of inspiratory resistive loads. Magnitude estimation was measured with handgrip estimation of resistive load magnitude. Perception of intrinsic loads was by methacholine bronchoprovocation in doses sufficient to a drop to 40% below baseline of forced expired volume in 1 sec (FEV(1)). Chest tightness, breathlessness, and air hunger, as estimated by a Borg scale were, used to rate methacholine perception. Life-threatening asthma subjects had a lower slope than nonlife-threatening asthma subjects for magnitude estimation of resistive loads. Life-threatening asthma patients also had a lower maximum Borg score for all three symptoms. There was no significant difference in magnitude estimation of symptom type.These results suggest that life-threatening asthma subjects have poor perception of extrinsic and intrinsic loads. This suggests that there is a similarity between the sensations elicited by intrinsic and extrinsic loads, allowing for the identification of poor-perceiving patients with either method of assessment and who suffer from life-threatening asthma.
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PMID:Perception of intrinsic and extrinsic respiratory loads in children with life-threatening asthma. 1242 40

Mechanical vibration of the chest wall can reduce dyspnea. It is unclear which sensations of respiratory discomfort are modulated by vibration (work/effort, air hunger, tightness). We performed two experiments to test whether vibration modifies air hunger: Experiment 1-eight adults performed six breath holds and rated their uncomfortable 'urge to breathe.' Vibration was applied separately at four chest-wall and two control sites, using two amplitudes. Breath-hold duration and ratings were unchanged by vibration at any site or amplitude. Experiment 2-nine adults were mechanically ventilated (mean 8.73 L/min) at constant hypercapnia (mean 48 mmHg) to produce mild to moderate ratings of air hunger (mean 37% of scale) with minimal respiratory muscle work. Vibration at 2nd or 3rd intercostal spaces during either inspiration or expiration did not change air hunger compared to triceps vibration. These experiments demonstrated that vibration does not relieve air hunger; we postulate that the effect of vibration is specific to the form of dyspnea.
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PMID:Mechanical chest-wall vibration does not relieve air hunger. 1266 98


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