Blood Gas Abnormalities Research Articles

Quantitative spectral analysis of vigilance EEG in patients with obstructive sleep apnoea syndrome

Sleep disruption and blood gas abnormalities, observed in patients with obstructive sleep apnoea (OSA) syndrome, prevent sleep-related restorative processes and induce chemical or structural central nervous system cellular injury. The aim of the study was to determine electroencephalogram (EEG) alterations related to the severity of OSA in patients with OSAS and the effect of the nasal continuous positive air pressure (nCPAP) treatment. Polysomnography and vigilant EEGs were performed in subjects with possible OSA. The mean relative power was calculated for delta, theta, alpha and beta frequency bands. Thirty subjects without and 131 with OSA participated in this study. In 29 male patients with severe OSA, quantitative EEGs were re-evaluated after 6 months of CPAP treatment. Compared to subjects without OSA, patients with severe OSA showed an increase in relative theta and delta power (occipital, temporal and parietal areas). Six months of nCPAP treatment improved daytime sleepiness of OSA patients. EEG demonstrated a decrease in alpha (frontal, central and temporal areas) and theta (frontal areas) relative power. However, beta relative power was increased mainly in central, and delta relative power, in all brain areas. In conclusion, EEG slowing was observed in OSA patients. CPAP treatment improved daytime sleepiness of OSA patients in contrast to the alterations in alpha (decreased) and delta (increased) relative power suggesting a possible persistent brain dysfunction.

FETAL UMBILICAL CORD BLOOD ERYTHROPOIETIN, INTERLEUKIN-6, PH, PO2, PCO2, AND BASE EXCESS LEVELS IN HISTOLOGIC AND/OR CLINICAL CHORIOAMNIONITIS: IS THE RESPONSE ONLY INFLAMMATORY?

To determine the correlation of histological chorioamnionitis (CA) with and without clinical CA with umbilical cord blood gases, erythropoietin (EPO), and interleukin-6 (IL-6) levels. Umbilical artery blood gas analysis (pH, pO(2), pCO(2), BE) and umbilical vein EPO and IL-6 levels were measured in 202 infants from normal, histological, and no clinical CA and histological plus clinical CA pregnancies. Umbilical artery blood gas analyses were not different between normal controls and histological and clinical CA groups. Blanc Stage 1 histological CA had no abnormal EPO or IL-6 umbilical blood results. EPO in umbilical venous blood was elevated only in those infants with both histological and clinical CA. Umbilical vein IL-6 levels were elevated in all advanced microscopic and clinical CA. High and low EPO groups also have corresponding high and low IL-6 levels suggesting a common stimulus for these substances. Blanc stage I histological CA is probably clinically insignificant. CA is infrequently associated with abnormal umbilical artery blood gas levels. Advanced histological and clinical CA can elevate both EPO and IL-6 in umbilical blood and these may be key elements of mechanisms that effect fetal brain function.

Intrapartum fetal heart rate monitoring in cases of congenital heart disease

We evaluated the intrapartum fetal heart rate (FHR) patterns in fetuses with congenital heart disease (CHD). One hundred sixteen cases of fetal CHD were identified at our institute between 2000-2007; 464 fetuses without CHD were used as controls. The incidences of abnormal FHR patterns and umbilical blood gases were compared. More fetuses with CHD showed variant FHR than did control fetuses (46.6% vs 17.7%; P < .01). Cesarean section deliveries that were based on fetal indications were performed more frequently in fetuses with CHD than in control fetuses (12.9% vs 3.2%; P < .01). Isomerism and tetralogy of Fallot were observed frequently with variant FHR. When chromosomal abnormalities and intrauterine growth restriction were excluded, the fetuses with CHD showed more variant FHR than did the control fetuses. Fetuses with CHD are more likely to show abnormal FHR patterns than are control fetuses. We suggest that cardiac abnormalities are associated with abnormalities in FHR patterns.

Double‐outlet right ventricle in a 10‐month‐old Friesian filly

A 10-month-old Friesian filly had a presentation that was consistent with chronic left- and right-sided congestive heart failure. Clinical pathology findings included abnormal haematological and biochemical variables, abnormal blood gas values and increased serum concentration of cardiac troponin I. Echocardiography revealed cardiac chamber dilation and dextropositioning of the aorta. Radiography revealed a generally enlarged heart and pulmonary interstitial infiltration. These findings were supported at necropsy and the diagnosis of double-outlet right ventricle was confirmed. The pathological changes and physiological responses subsequent to double-outlet right ventricle have not previously been described in detail in horses. Clinical progression closely resembles that seen in humans, in whom antemortem diagnosis relies on echocardiography. In horses, complex cardiac disease presents a diagnostic challenge to the clinician. Appropriate therapy must be based on an accurate diagnosis.

FETAL UMBILICAL CORD BLOOD ERYTHROPOIETIN, INTERLEUKIN-6, PH, PO2, PCO2, AND BASE EXCESS LEVELS IN HISTOLOGIC AND/OR CLINICAL CHORIOAMNIONITIS: IS THE RESPONSE ONLY INFLAMMATORY?

Objective: To determine the correlation of histological chorioamnionitis (CA) with and without clinical CA with umbilical cord blood gases, erythropoietin (EPO), and interleukin-6 (IL-6) levels. Methods: Umbilical artery blood gas analysis (pH, pO2, pC02, BE) and umbilical vein EPO and IL-6 levels were measured in 202 infants from normal, histological, and no clinical CA and histological plus clinical CA pregancies. Results: Umbilical artery blood gas analyses were not different between normal controls and histological and clinical CA groups. Blanc Stage 1 histological CA had no abnormal EPO or IL-6 umbilical blood results. EPO in umbilical venous blood was elevated only in those infants with both histological and clinical CA. Umbilical vein IL-6 levels were elevated in all advanced microscopic and clinical CA. High and low EPO groups also have corresponding high and low IL-6 levels suggesting a common stimulus for these substances. Conclusions: Blanc stage I histological CA is probably clinically insignificant. CA is infrequently associated with abnormal umbilical artery blood gas levels. Advanced histological and clinical CA can elevate both EPO and IL-6 in umbilical blood and these may be key elements of mechanisms that effect fetal brain function.

Meconium-stained amniotic fluid and meconium aspiration syndrome: a prospective study

The incidence of meconium aspiration syndrome (MAS), associated perinatal factors, morbidity and deaths varies widely. This study aimed to assess the perinatal attributes and morbidity associated with MAS. Over a 2-year period, all neonates born through meconium-stained amniotic fluid (MSAF) were observed for respiratory distress (RD). Birth details, chest radiograph (CXR) and clinical course were documented. Neonates with consistent CXR findings whose RD could not otherwise be explained were defined as MAS. Of 409 neonates born through MSAF, meconium was thick in 196 (47.9%). Fifty-five (13.4%) had RD and 45 (11.3%) were consistent with MAS. Six (1.5%) neonates died. Mean (SD) birthweight and gestation of MAS infants were 2721.9 (510.2) g and 38.67 (1.09) weeks, respectively. About one-third were of low birthweight and 28 were born by caesarean section. On univariate analysis, caesarean delivery, meconium in the trachea and thick meconium were the significant perinatal factors for the development of MAS. On multiple regression analysis, thick meconium was the only independent factor for MAS (OR 7.08, 95% CI 3.08-16.27, p<0.001). An Apgar score of <or=6 and blood gas abnormalities were found in 44.4% and 48.9%, respectively. Air leak syndrome was observed in 12 (26.7%), persistent pulmonary hypertension in seven and severe asphyxia and late sepsis in two each. Thirteen (28.9%) required mechanical ventilation and six (13.3%) died. MAS occurred in 11.3% of neonates born through MSAF. Thick meconium was found to be an important causative factor. Nearly one-third of infants with MAS required mechanical ventilation and 13.3% died.

Prevalence of Hepatopulmonary Syndrome in Children

The hepatopulmonary syndrome is defined as a triad of liver disease, hypoxemia, and intrapulmonary vascular dilation. The reported prevalence of hepatopulmonary syndrome in adults with cirrhosis ranges from 4% to 29%; however, the prevalence of hepatopulmonary syndrome and its outcome in children is unknown. The objective of this study was to describe prospectively the prevalence of intrapulmonary vascular dilation and hepatopulmonary syndrome in children with liver disease. Pulse oximetry was undertaken in children with liver disease, and those with oxygen saturation < or = 97%, those with cirrhosis, and those with clinically severe portal hypertension from other causes underwent contrast-enhanced echocardiography for detection of intrapulmonary vascular dilations. Patients with intrapulmonary vascular dilation underwent arterial blood gas analysis and technetium-99m-labeled macroaggregated albumin scan. Oxygen saturation was measured in 301 children and was < or = 97% in 8. These 8 and an additional 18 patients with cirrhosis or portal hypertension underwent contrast-enhanced echocardiography. Seven (27%) patients had intrapulmonary vascular dilation detected by contrast-enhanced echocardiography; 2 of these patients had abnormal arterial blood gas analysis and thus met diagnostic criteria for hepatopulmonary syndrome (representing 8% of patients with cirrhosis or severe portal hypertension). Both patients with hepatopulmonary syndrome had abnormal pulse oximetry. Technetium-99m-labeled macroaggregated albumin scans for 6 patients showed a median 6.5% (range: 4%-12%) tracer uptake outside the lungs. Hepatopulmonary syndrome occurs in an important minority of children with cirrhosis or severe portal hypertension. Additional studies should be undertaken to determine the importance of intrapulmonary vascular dilation without hepatopulmonary syndrome and the impact of hepatopulmonary syndrome on the outcomes of affected children.

Clinical validation of the signs and symptoms and the nature of the respiratory nursing diagnoses in patients under invasive mechanical ventilation*

The aims of this study were to validate the signs and symptoms of the respiratory nursing diagnoses impaired gas exchange, ineffective airway clearance and ineffective breathing pattern in patients under mechanical ventilation; to verify whether intubation time and ventilatory modalities were related factors for respiratory nursing diagnoses; to verify the occurrence of shared signs and symptoms in the diagnoses and compare them with North American Nursing Diagnosis Association's proposition and to ascertain whether respiratory nursing diagnoses occur in isolated or associated patterns. The need for mechanical ventilation is common in several patients admitted to intensive care units. Therefore, critical care nurses should identify the respiratory nursing diagnoses of high incidence. Descriptive observational study, with 177 evaluations of surgical and medical critically ill adult patients undergoing invasive mechanical ventilation. The study adopted Fehring's Modified Clinical Diagnostic Validity Model, with a suggested alteration. The critical signs and symptoms were the same as proposed by North American Nursing Diagnosis Association, when the diagnoses were separately identified, although no particular sign and symptom was found for ineffective breathing pattern. Impaired gas exchange and ineffective airway clearance were identified as having 88 (49.7%) evaluations sharing the critical signs and symptoms. Intubation time and ventilation modality were related factors for the development of ineffective airway clearance and ineffective breathing pattern. The critical signs and symptoms of impaired gas exchange were abnormal blood gases and hypoxemia. For ineffective airway clearance, they were rhonchi and decreased breath sounds. No highlights were found for ineffective breathing pattern signs and symptoms. Validation by experts has confirmed these findings. The interface between ineffective airway clearance and impaired gas exchange was confirmed by the presence of the shared critical signs and symptoms. Studies like this are relevant to clinical practice because they evaluate the adequacy of Taxonomy II for patients under mechanical ventilation in clinical practice, thus allowing for the intensive care nurses to go from one mechanical and routine practice to a critical, reflexive practice, committed to professional progress.

Mortality-related factors after hospitalization for acute exacerbation of chronic obstructive pulmonary disease: the burden of clinical features

Background There is limited information about factors associated with mortality of patients with chronic obstructive pulmonary disease (COPD) admitted to hospital because of an acute exacerbation. Methods A retrospective cohort study including all patients admitted to hospital through our emergency department (ED) was conducted. A total of 972 electronic discharge reports were reviewed. Patient baseline features, aspects concerning acute exacerbation, as well as demographic, cardiac ultrasound, and microbiological data were collected. Results In-hospital mortality rate was 6.4%. Of 315 patients with mild exacerbation according to Anthonisen criteria, only 1 died. In the univariate analysis, moderate to severe acute exacerbation of COPD, age older than 75 years, severe COPD, abnormal blood gas values, onset of complications during hospital stay, radiologic consolidation, a positive result in a microbiological respiratory sample, home oxygenotherapy, admission to the intensive care unit, left ventricular ejection fraction, and department of admission were statistically significant ( P < .05). The multivariate analysis showed that moderate to severe COPD acute exacerbation (odds ratio [OR] 7.3; 95% confidence interval [CI], 3.6-17.7), age older than 75 years (OR 4.9; 95% CI, 2.3-10.8), severe COPD (OR 4.6; 95% CI, 2.1-10), abnormal blood gas values (OR 4.7; 95% CI, 1.1-19.8), and complication during hospital stay (OR 2.8; 95% CI 1.4-5.4) were independently related to mortality. Conclusion We found that clinical aspect appears the most relevant of all potential determinants of in-hospital mortality for patients admitted for acute exacerbation of COPD. Thus, the clinical assessment and therapeutic decision taken in this first moment at the ED are the key that predict the prognosis of this patients. These data suggest that the risk of mortality after the admission to hospital of patients with COPD because of an acute exacerbation can be successfully predicted by making a clinical assessment at the ED.

Culture‐Positive Sepsis in Neonatal Camelids: 21 Cases

Background:There is limited literature on neonatal bacterial sepsis in New World (NW) camelids.Hypothesis:Bacterial culture‐positive crias have clinical differences based on the specific bacterial genera isolated.Animals:Bacterial culture‐positive NW camelid crias &lt;21 days of age from 1990 to 2005 were included.Methods:Historic physical examination and cliniopathologic data were retrieved from medical records as were the identity and antibiograms of bacterial isolates. Cases were categorized by outcome (survival versus nonsurvival) and type of sepsis (gram‐negative or gram‐positive). Kruskal‐Wallis and chi‐square testing were used to evaluate differences between groups.Results:Twenty‐one crias met the inclusion criteria. Median age was 2 days. Failure of passive transfer was common. There were few differences identified on the basis of outcome or type of sepsis. Crias without gastrointestinal or central nervous system involvement survived in greater numbers. Forty‐six percent of isolates were gram‐positive. The most common isolates were the following:Escherichia coli, Enterococcusspp.,Listeria monocytogenes, andCitrobacterspp. Overall survival was 67% (14/21).Conclusions and Clinical Importance: Crias with sepsis do not appear to present with major biochemical, hematologic, or blood gas abnormalities, potentially complicating diagnosis. Affected crias may not have localizing signs at presentation and are not usually febrile, although hypothermia, tachypnea, and tachycardia are relatively common. Total protein concentration was not a substitute for immunoglobulin G measurement in septic crias in this study. Familiarity with the clinical presentation and common pathogens isolated should improve early recognition and treatment and ultimately outcome of crias with sepsis.

Prognostic value of blood gas analyses in patients with idiopathic pulmonary arterial hypertension

Blood gas abnormalities in patients with idiopathic pulmonary arterial hypertension (IPAH) may be related to disease severity and prognosis. The present authors performed a 12-yr retrospective analysis assessing arterialised capillary blood gases, haemodynamics, exercise variables and survival in 101 patients with IPAH. At baseline, arterial oxygen tension (P(a,O(2))) and carbon dioxide arterial tension (P(a,CO(2))) were 9.17+/-1.86 and 4.25+/-0.532 kPa, respectively. While P(a,O(2) )was not associated with survival, a low P(a,CO(2 ))was a strong and independent prognostic marker. When patients were divided according to a baseline P(a,CO(2 ))value above or below 4.25 kPa, a cut-off value determined by receiver operating characteristics analysis, survival rates were 98 and 86% at 1 yr, 82 and 69% at 2 years, 80 and 51% at 3 yrs, 77 and 41% at 5 yrs, and 65 and 12% at 8 yrs, respectively. P(a,CO(2 ))after 3 months of medical therapy was strongly associated with survival. Hypocapnia at rest and during exercise correlated with low cardiac output, low peak oxygen uptake and reduced ventilatory efficacy. Multiple regression analysis revealed that 6-min walking distance, right atrial pressure and P(a,CO(2 ))were independently associated with survival. In patients with idiopathic pulmonary arterial hypertension, hypocapnia (carbon dioxide arterial tension <4.25 kPa) is an independent marker of mortality.

Culture-Positive Sepsis in Neonatal Camelids: 21 Cases

There is limited literature on neonatal bacterial sepsis in New World (NW) camelids. Bacterial culture-positive crias have clinical differences based on the specific bacterial genera isolated. Bacterial culture-positive NW camelid crias <21 days of age from 1990 to 2005 were included. Historic physical examination and cliniopathologic data were retrieved from medical records as were the identity and antibiograms of bacterial isolates. Cases were categorized by outcome (survival versus nonsurvival) and type of sepsis (gram-negative or gram-positive). Kruskal-Wallis and chi-square testing were used to evaluate differences between groups. Twenty-one crias met the inclusion criteria. Median age was 2 days. Failure of passive transfer was common. There were few differences identified on the basis of outcome or type of sepsis. Crias without gastrointestinal or central nervous system involvement survived in greater numbers. Forty-six percent of isolates were gram-positive. The most common isolates were the following: Escherichia coli, Enterococcus spp., Listeria monocytogenes, and Citrobacter spp. Overall survival was 67% (14/21). Crias with sepsis do not appear to present with major biochemical, hematologic, or blood gas abnormalities, potentially complicating diagnosis. Affected crias may not have localizing signs at presentation and are not usually febrile, although hypothermia, tachypnea, and tachycardia are relatively common. Total protein concentration was not a substitute for immunoglobulin G measurement in septic crias in this study. Familiarity with the clinical presentation and common pathogens isolated should improve early recognition and treatment and ultimately outcome of crias with sepsis.

Myocardial infarction and nocturnal hypoxaemia

There is an increased risk of cardiovascular morbidity and mortality in patients with nocturnal intermittent hypoxaemia. The aim of this study was to evalute the influence of nocturnal hypoxaemia on ventricular arrhythmias and myocardial ischaemia in patients with myocardial infarction (MI). We studied 77 patients (55.8 +/- 7.9 years) with MI free of complications, chronic pulmonary diseases, abnormal awake blood gases tension. All patients underwent overnight pulse oximetry and 24-hour electrocardiography. Patients were divided into two groups according to nocturnal hypoxaemia. Total number of ventricular premature complex (VPC); maximal VPC/h; incidence of VPC Lown class > 2 and occurrence of ST-segment depression were analysed for nocturnal (10 PM to 6 AM), daytime (6 AM to 22 PM) periods and for the entire 24 hours. Both groups were similar in age, gender, standard risk factors, myocardial infarction size and did not differ in VPC during the analysed periods. The number of nocturnal maximal VPC/h was insignificantly greater in group 1 (with hypoxaemia) compared to group 2 (without hypoxaemia), (p = 0.084). Maximal VPC/h did not differ significantly either for daytime or for 24 hours among the groups. Nocturnal VPC Lown > 2 were significantly more frequent in group 1 (25% vs 0%, p = 0.002). The incidence of VPC Lown > 2 was similar during the daytime, and during 24 hrs in both groups. Occurrence of ST-segment depression did not differ between groups 1 and 2. Nocturnal hypoxaemia was associated with complex nocturnal ventricular arrhythmias in patients with MI.

Point:Counterpoint: The parafacial respiratory group (pFRG)/pre-Bötzinger complex (preBötC) is the primary site of respiratory rhythm generation in the mammal

Point:Counterpoint: The parafacial respiratory group (pFRG)/pre-Bötzinger complex (preBötC) is the primary site of respiratory rhythm generation in the mammal

Hormonal regulation of alveolarization: structure-function correlation

BackgroundDexamethasone (Dex) limits and all-trans-retinoic acid (RA) promotes alveolarization. While structural changes resulting from such hormonal exposures are known, their functional consequences are unclear.MethodsNeonatal rats were treated with Dex and/or RA during the first two weeks of life or were given RA after previous exposure to Dex. Morphology was assessed by light microscopy and radial alveolar counts. Function was evaluated by plethysmography at d13, pressure volume curves at d30, and exercise swim testing and arterial blood gases at both d15 and d30.ResultsDex-treated animals had simplified lung architecture without secondary septation. Animals given RA alone had smaller, more numerous alveoli. Concomitant treatment with Dex + RA prevented the Dex-induced changes in septation. While the results of exposure to Dex + RA were sustained, the effects of RA alone were reversed two weeks after treatment was stopped. At d13, Dex-treated animals had increased lung volume, respiratory rate, tidal volume, and minute ventilation. On d15, both RA- and Dex-treated animals had hypercarbia and low arterial pH. By d30, the RA-treated animals resolved this respiratory acidosis, but Dex-treated animals continued to demonstrate blood gas and lung volume abnormalities. Concomitant RA treatment improved respiratory acidosis, but failed to normalize Dex-induced changes in pulmonary function and lung volumes. No differences in exercise tolerance were noted at either d15 or d30. RA treatment after the period of alveolarization also corrected the effects of earlier Dex exposure, but the structural changes due to RA alone were again lost two weeks after treatment.ConclusionWe conclude that both RA- and corticosteroid-treatments are associated with respiratory acidosis at d15. While RA alone-induced changes in structure andrespiratory function are reversed, Dex-treated animals continue to demonstrate increased respiratory rate, minute ventilation, tidal and total lung volumes at d30. Concomitant treatment with Dex + RA prevents decreased septation induced by Dex alone and results in correction of hypercarbia. However, these animals continue to have abnormal pulmonary function and lung volumes. Increased septation as a result of RA treatment alone is reversed upon discontinuation of treatment. These data suggest that Dex + RA treatment results in improved gas exchange likely secondary to normalized septation.

Increases in tissue Pco2 during circulatory shock reflect selective decreases in capillary blood flow*

Tissue Pco2 reflects metabolic alterations due to circulatory failure during circulatory shock. This study addresses simultaneous changes in gastric and buccal tissue Pco2 with changes in microcirculatory blood flow in a rat model of circulatory shock induced by cecal ligation and puncture. Prospective controlled laboratory study. University-affiliated research laboratory. Male breeder Sprague-Dawley rats. Induction of polymicrobial, abdominal sepsis by cecal ligation and puncture. Tissue Pco2 was continuously measured with the aid of a miniature carbon dioxide electrode. Using orthogonal polarization spectral imaging, recordings of the microcirculation were taken at baseline and hourly intervals until death and compared with sham-operated animals. Gastric and buccal tissue Pco2 values progressively increased in animals after cecal ligation and puncture and terminated in death. Microcirculatory blood flow in vessels >20 microm was well preserved during progression of shock, whereas there was an early and progressive decrease in microcirculatory blood flow in vessels <20 microm, mostly representing capillaries. Tissue Pco2, the tissue Pco2-Paco2 gradient, and blood flow in vessels <20 microm were highly correlated. This contrasted with sham control animals in which no significant hemodynamic, blood gas, lactate, microcirculatory, and tissue Pco2 abnormalities were observed. These observations suggest that microcirculatory failure in capillaries appears as an early defect in close association with anaerobic metabolism during progression of circulatory shock in an animal model of septic peritonitis.

Significance of continuous blood gas monitoring in cardiac surgery with cardiopulmonary bypass

Significance of continuous blood gas monitoring in cardiac surgery with cardiopulmonary bypass

Role of arterial blood gas abnormalities in oedema formation in COPD

Renal and hormonal abnormalities, manifesting as oedema or hyponatraemia, are often seen in patients with COPD. The aim of this study was to investigate the effect of airflow obstruction and arterial blood gas abnormalities on oedema formation in COPD patients. A total of 58 COPD patients hospitalized for treatment of COPD exacerbation were admitted to the study. Of these, 38 patients had peripheral oedema (group 1) and 20 patients had no oedema (group 2). The mean age was 68 +/- 9 years in group 1 and 68 +/- 8 years in group 2. On the first day of admission, serum urea was 29.18 +/- 12.25 mg/dL and creatinine was 1.62 +/- 0.46 mg/dL in group 1, while urea was 15.50 +/- 4.59 mg/dL and creatinine was 1.07 +/- 0.10 mg/dL in group 2. Hyponatraemia occurred in five patients (13%) in group 1 and one patient (5%) in group 2. There was no difference in severity of airflow obstruction in the two groups; FEV1 was 44 +/- 15% of predicted and FEV1/FVC was 53 +/- 14 in group 1, while FEV1 was 45 +/- 16% of predicted and FEV1/FVC was 54 +/- 20 in group 2. There were statistically significant differences in pH (7.32 vs. 7.39; P= 0.013) and in PaCO2 (62 +/- 10 mmHg vs. 42 +/- 6; P= 0.048) for group 1 compared with group 2. PaO2 (62 +/- 17 mmHg vs. 82 +/- 27) and SaO2 (87 +/- 9%vs. 90 +/- 13) were found to be lower in group 1 compared with group 2 but the difference did not reach statistical significance. Alterations in pH and PaCO2 (respiratory acidosis and hypercapnia) appear to have more prominent roles than hypoxaemia in oedema formation in COPD patients.

Middle Ear Pressure in Patients with Dizziness

The middle ear pressure was analyzed in 112 patients with dizziness. In 37 patients with Meniere's disease, the middle ear pressure on the low-pressure side was significantly lower, the middle ear pressure difference (between the high and low sides) was significantly larger, and the maximum compliance on the low-compliance side was significantly lower than in normal volunteers. The middle ear pressure difference was significantly larger during periods of dizziness or recurrent dizziness than at the time of remission. In patients with Meniere's disease, a middle ear pressure difference of more than 50 decapascals was significantly more common among those with abnormal blood gas levels than among those with normal blood gas levels. In 27 patients with cervical vertigo and 15 patients with vertebrobasilar insufficiency, the middle ear pressure difference was also significantly larger than in normal volunteers. These results suggest that the middle ear pressure difference might be closely related to dizziness in Meniere's disease and less closely related in cervical vertigo or vertebrobasilar insufficiency. The middle ear pressure difference might also be related to abnormal blood gas levels in patients with dizziness.

Intrapartum fetal heart rate monitoring in cases of cytomegalovirus infection

ObjectiveSeveral studies have shown that abnormal intrapartum fetal heart rate patterns are the results from pre-existing fetal brain damage. We evaluated intrapartum fetal heart rate pattern of cytomegalovirus-infected fetuses and correlated the patterns with neurologic outcomes. Study designBetween 1991 and 2001, there were 20 cytomegalovirus-infected fetuses. We selected 40 fetuses as control subjects that were matched for gestational age and birth weight. Fetal heart rate was interpreted according to the guidelines of the National Institute for Child and Human Development. The incidence of abnormal fetal heart rate pattern and umbilical blood gases were compared between both groups. We also investigated the factors that contributed to abnormal fetal heart rate pattern in the cytomegalovirus group. ResultsNonreassuring fetal heart rate patterns (prolonged deceleration and recurrent late deceleration) were observed in 8 of 20 fetuses (prolonged deceleration, 7 fetuses; recurrent late deceleration, 1 fetus) in the cytomegalovirus group and in 3 of 41 fetuses (prolonged deceleration, 1 fetus; recurrent late deceleration, 2 fetuses) in the control group (P<.05, Fisher test). Baseline fetal heart rate variability was minimal in 4 of the 7 prolonged deceleration cases in the cytomegalovirus group. Umbilical pH <7.1 was found for 1 fetus in the cytomegalovirus group. The average umbilical arterial pH values were similar in both the groups. In the cytomegalovirus group, there were no differences in the incidence of contributing factors between 8 fetuses with abnormal fetal heart rate pattern (prolonged deceleration and recurrent late deceleration) and 8 fetuses with no change. There were 3 fetuses with cerebral palsy: 2 fetuses in the no change group and 1 fetus in the prolonged deceleration group. Antigenemia was positive exclusively in 4 cases with abnormal fetal heart rate pattern (P<.05). ConclusionCytomegalovirus-infected fetuses are more likely to show abnormal intrapartum fetal heart rate patterns than low-risk control fetuses, which suggests that the perinatal detection of cytomegalovirus is necessary to distinguish hypoxic-ischemic encephalopathy.