No abstract available.
Hirschsprung Disease* ; Hypoventilation*

BACKGROUND: There are many factors such as diffusion abnormality, V/Q mismatch, intrapulmonary shunt, alveolar hypoventilation and FIO2 in reducing arterial hypoxemia. Intrapulmonary shunting can be due to blood going from the right to the left side of the heart without respiring with alveolar gas(true shunt mechanism) or blood that respires but achieves a PaO2 less than the ideal (shunt effect mechanism). Understanding the portion of true shunt in patients with hypoxemia is very important indicator to analyze the effects of oxygen therapy. Several equations are used for calculation of physiologic shunt. The aim of this study was to calculate and compare shunts derived from four shunt equations; classic physiologic, estimated, modified clinical and simple equations. METHOD: After cardiovascular stability following open heart surgery, 40 patients were mechanically ventilated with an FIO2=1.0. Arterial and mixed blood gases were measured. We calculated and compared shunts by classic physiologic [S/T=(CcO2 CaO2)/(CcO2 CO2)], estimated [S/T=(CcO2 CaO2)/ (3.5 CcO2 CO2)], modified clinical [S/T= AaDO2 0.0031/(AaDO2 0.0031 CcO2 CaO2)], and simple equations [S/T=AaDO2/20]/ RESULTS: Shunts by classic physiologic, estimated, and modified clinical shunt equation were 26.9 8.5%, 25.1 7.1%, and 26.3 8.2%, respectively and did not differ one another significantly. Shunts by simple shunt equations was 18.8 6.2% and significantly lower than those by other 3 equations(P<0.05). CONCLUSIONS: It is reasonable to conclude that in post-open heart patients with stable cardiovascular function and mechanically ventilated with an FIO2=1.0, classic physiologic, estimated, and modified clinical shunt equations show a reliable reflection of the physiologic shunt. But simple equation (AaDO2/20) might be used as a simple estimate.
Anoxia ; Diffusion ; Gases ; Heart ; Humans ; Hypoventilation ; Oxygen ; Thoracic Surgery

Child, Preschool ; Humans ; Male ; Obesity Hypoventilation Syndrome ; diagnosis ; therapy

BACKGROUND AND PURPOSE: Cerebrovascular reactivity (CVR) can be estimated by measuring the change of cerebral blood flow that occurs during vasostimulation. To estimate the cerebrovascular reactivity, we investigated the change of flow velocity of the internal carotid artery (ICA) and the middle cerebral artery (MCA) during hyperventilation and hypoventilation with the transcranial doppler. So we studied whether the CVR measured by this method could show a significant difference between the normal and the atherosclerotic subjects and whether the CVR may decrease with age in normal gubjects. METHODS: Using transcranial doppler, we measured the mean velocity (Vm), the pulsatility index (P.I.) at the resting state, the end of breath-holding and the end of hyperventilation in 30 normal and 10 atherosclerotic subjects, so we calculated the percentile change of mean velocity (% Vm) and P.I. (% P.I.) after the vasostimulation. We estimated the change of Vm, P.I., % Vm and % P.I. By the age group and compared those parameters between the age-matched normal control and atherosclerotic subjects. RESULTS: The Vm in ICA and MI significantly decreased with age (p<0.01), but there was no significant difference in Vm and P. I. Between normal and atherosclerotic subjects. The % Vm and % P.I. In response to hyperventilation significantly decreased with age in ICA, M1, M2 and there was significant difference in % Vm of ICA and M1 after breath-holding and % Vm of ICA after hyperventilation between the normal and atherosclerotic subjects. CONCLUSION: The breath-holding and hyperventilation tests could be non-invasive and useful methods in estimation of the cerebrovascular reactivity and could be applied in the basal and follow-up evaluation of the cerebrovascular reserve of the ischemic stroke patients.
Carotid Artery, Internal ; Humans ; Hyperventilation ; Hypoventilation ; Middle Cerebral Artery ; Stroke

Humans ; Sleep Apnea, Central/therapy* ; Hypoventilation/congenital* ; Homeodomain Proteins

Obesity-Hypoventilation syndrome (OHS) is characterized by morbid obesity, hypoxia, and hypercapnea during wakefulness without parechymal lung disease or severe obstructive sleep apnea. A woman was admitted because of mental deterioration and diagnosed as OHS on the basis of obesity and hypoventilation, while awake, after ruling out other causes. By bilevel positive airway pressure (BiPAP) therapy, hypercapnea and hypoxia were resolved. We report that BiPAP can be an effective treatment for severe hypercapnea and hypoxia in OHS, which obviate the need for invasive endotracheal intubation.
Anoxia ; Female ; Humans ; Hypoventilation ; Intubation, Intratracheal ; Lung Diseases ; Obesity ; Obesity Hypoventilation Syndrome* ; Obesity, Morbid ; Sleep Apnea, Obstructive ; Wakefulness

BACKGROUND: The purpose of this study was to define morphine's effects on resting ventilation and the ventilatory response to hypoxia and hypercarbia. METHODS: Six healthy nonsmoking young adult males were tested for the respiratory effects of intravenous morphine (0.15 mg/kg). Test began with baseline measurement of resting ventilation, isocapnic hypoxic ventilatory response (HVR), and normoxic hypercapnic ventilatory response (HCVR). After baseline measurement, morphine was administered and ventilatory responses were determined 20 and 40 min postinfusion. RESULTS: Morphine significantly decreased resting ventilation, hypoxic ventilatory response, and hypercarbic ventilatory response. Resting hypoventilation manifested as a peak rise in PETCO2 from 38.0+/-1.4 to 42.8+/-1.0 mmHg ( SEM) at 20 min (p<0.05). Hypoxic ventilatory response, measured as the slope of the ventilatory response to hypoxia, decreased from a control of 20.7+/-3.8 to 14.5+/-7.2 at 20 min after morphine (p<0.05). Hypercapnic ventilatory response, measured as the slope of the ventilatory response to hypercarbia, also decreased from 34.9+/-7.5 to 11.1+/-4.9 (p<0.05) 20 min after morphine. CONCLUSION: These decreased responsiveness to the chemical stimuli to breathing may contribute to the ventilatory depression frequently seen after administration of morphine.
Anoxia* ; Humans ; Hyperventilation* ; Hypoventilation ; Male ; Morphine* ; Respiration ; Respiratory Insufficiency ; Ventilation ; Young Adult

Sleep-disordered breathing in children can include habitual snoring, obstructive hypoventilation, upper airway resistance syndrome, and obstructive sleep apnea. Obstructive hypoventilation in children is characterized by CO₂ retention caused by prolonged partial upper airway obstruction during sleep. To date, there have been few studies regarding the clinical significance and management strategies in pediatric obstructive hypoventilation, although it is a unique feature of pediatric sleep-disordered breathing. In this report, we describe two cases of obstructive hypoventilation that demonstrated improvement following upper airway surgery. These results suggest that upper airway surgery could be an additional treatment modality in obstructive hypoventilation.
Airway Obstruction ; Airway Resistance ; Child ; Humans ; Hypoventilation* ; Sleep Apnea Syndromes ; Sleep Apnea, Obstructive ; Snoring

BACKGROUND: This randomized study was designed to evaluate the analgesic effectiveness and to determine the optimal dose of remifentanil when administered as intermittent bolus injection during infiltration of local anesthetics for patients undergoing plastic surgery. METHODS: Forty five ASA I or II patients undergoing plastic surgery were randomly assigned to one of the three bolus doses of remifentanil injection. Five minutes after receiving midazolam 0.05 mg/kg IV, remifentanil was injected intravenously one minute before the infiltration of local anesthetics: A bolus of remifentanil 0.25microgram/kg was injected in Group R0.25 (n = 15), 0.50 microgram/kg in Group R0.5 (n = 15), or 0.75microgram/kg in Group R0.75 (n = 15). After assessment of the patients' Observer's Assessment of Alertness/Sedation (OAA/S) scale, the subjective pain level during local anesthetic infiltration was evaluated. Respiratory rate, SpO2, mean blood pressure, and heart rate were recorded during the study period. Postoperative nausea/vomiting and patient's satisfaction were checked by telephone call. RESULTS: OAA/S scale values were similar among the three groups (3-4). The number of the patients who complained of moderate or severe pain level is significantly higher in group R0.25 than in group R0.5 or group R0.75 (P < 0.05). Adverse events such as hypoventilation, desaturation, and bradycardia were observed with significantly high frequency in R0.75 than in other two groups (P < 0.05). All three groups showed no occurrence of hypotension or postoperative nausea/vomiting. CONCLUSIONS: The above results demonstrate that intermittent bolus injection of remifentanil 0.50microgram/kg is recommended to accomplish desirable pain control during local anesthetic infiltration in those who received midazolam 0.05 mg/kg.
Anesthetics, Local ; Blood Pressure ; Bradycardia ; Heart Rate ; Humans ; Hypotension ; Hypoventilation ; Midazolam ; Respiratory Rate ; Surgery, Plastic* ; Telephone

Congenital central hypoventilation syndrome (CCHS) is a disorder of the autonomic nervous system characterized by a decreased response to hypercarbia. CCHS is frequently associated with congenital megacolon; the combination is called Haddad syndrome. CCHS is associated with dysfunction in respiratory features of the autonomic nervous system and with other disorders, including facial deformities, cardiovascular symptoms, and tumors. Patients with CCHS frequently have a mutation in the homeobox protein 2b (PHOX2B) gene. Most mutations involve heterozygous expansion of alanine repeats (GCN). Interestingly, a higher polyalanine repeat number is associated with a more severe clinical phenotype. To clarify the role of PHOX2B in disease pathogenesis, we introduce and review the clinical and molecular features of CCHS and Haddad syndrome.
Alanine ; Autonomic Nervous System ; Congenital Abnormalities ; Genes, Homeobox ; Hirschsprung Disease ; Humans ; Hypoventilation* ; Molecular Biology* ; Phenotype