Clinical outcomes of a specialised inpatient unit for adults with mild to severe intellectual disability and mental illness.

BACKGROUND: Limitations of general psychiatric services have led to the development of specialised psychiatric programmes for patients with intellectual disability (ID) and mental health needs. Few studies have examined treatment outcomes of specialised inpatient units, and no studies have explored how the effects of intervention may differ for individuals at varying levels of cognitive ability. The present study examined clinical outcomes of inpatients with mild ID in contrast to inpatients with moderate to severe ID within the same service. METHOD: Thirty-three patients (17 with mild ID and 16 with moderate to severe ID) discharged between 2006 and 2008 from a specialised inpatient unit in Canada for adults with ID and mental illness were studied. In addition to examining change in scores on clinical measures, outcomes with regard to length of stay, diagnostic change, residential change and re-admission to hospital were explored. RESULTS: Both groups demonstrated clinical improvement from admission to discharge. However, only patients with mild ID demonstrated improvements on the Global Assessment of Functioning. CONCLUSIONS: This study is one of the first to consider outcomes of higher and lower functioning individuals with ID on a specialised inpatient unit. Results suggest that outcomes may be different for these groups, and some clinical measures may be more sensitive to changes in patients with more severe disabilities.

LTR-retrotransposons and MITEs: important players in the evolution of plant genomes.

Retrotransposons are an abundant and ancient component of plant genomes, yet recent evidence indicates that element activity in many modern plants is restricted to times of stress. Stress activation of plant retrotransposons may be a significant factor in somaclonal variation, in addition to providing an important means to isolate new active elements. Long terminal repeat retrotransposons and a second class of elements we have called miniature inverted-repeat transposable elements (MITEs) have recently been found to be associated with the genes of diverse plants where some contribute regulatory sequences. Because of their sequence diversity and small size, MITEs may be a valuable evolutionary tool for altering patterns of gene expression.

The molecular evolution of terminal ear1, a regulatory gene in the genus Zea.

Nucleotide diversity in the terminal ear1 (te1) gene, a regulatory locus hypothesized to be involved in the morphological evolution of maize (Zea mays ssp. mays), was investigated for evidence of past selection. Nucleotide polymorphism in a 1.4-kb region of te1 was analyzed for a sample of 26 sequences isolated from 12 maize lines, five populations of the maize progenitor, Z. mays ssp. parviglumis, six other Zea populations, and two Tripsacum species. Although nucleotide diversity in te1 in maize is reduced relative to ssp. parviglumis, phylogenetic and statistical analyses of the pattern of polymorphism among these sequences provided no evidence of past selection, indicating that the region of the gene studied was probably not involved in maize evolution. The level of reduction in genetic diversity in te1 in maize relative to its progenitor is comparable to that found in previous reports for isozymes and other neutrally evolving maize genes and is consistent with a genome-wide reduction of genetic diversity resulting from a domestication bottleneck. An estimate of the age (1.2-1.4 million yr) of the maize gene pool based on te1 is roughly consistent with previous estimates based on other neutral genes, but may be biased by the apparently slow synonymous substitution rate at te1.

Catecholamines stimulate the synthesis and release of insulin-like growth factor binding protein-1 (IGFBP-1) by fetal sheep liver in vivo.

In fetal sheep, prolonged hypoxia (for 24 h) induced by a reduction in maternal uterine artery blood flow, increases insulin-like growth factor binding protein-1 (IGFBP-1) levels and decreases IGFBP-2 levels in the plasma, with corresponding changes in messenger RNA (mRNA) levels in the liver. Since IGFBP-1 synthesis in liver cells in vitro is stimulated by compounds that increase intracellular cAMP concentrations, we hypothesized that the increased IGFBP-1 synthesis during prolonged hypoxemia may be induced by circulating catecholamines, that are released during hypoxia, and that elevate fetal liver cAMP levels. Our aim was to determine the effect of 24-h catecholamine infusions on the synthesis and release of IGFBP-1 and IGFBP-2 in fetal sheep. Vascular catheters were implanted into fetuses at 110-115 days gestation in 14 pregnant ewes. After a 5-day recovery period, fetuses received a 24-h infusion of either norepinephrine (1 micrograms/kg.min, n = 5), epinephrine (0.25 micrograms/kg.min, n = 5), or vehicle (normal saline, n = 4). Fetal carotid arterial samples were collected at specified intervals throughout the infusion for the determination of blood glucose concentrations, plasma catecholamine concentrations by HPLC, insulin, and glucagon concentrations by RIA, and IGFBP levels by Western ligand blotting. After 24 h, the ewe and fetus were killed and selected fetal tissues (liver and kidney) were collected, and analyzed for IGFBP mRNA levels by northern blotting followed by laser densitometric quantification. Plasma catecholamine concentrations were increased in treated fetuses to levels that may be expected in fetuses subjected to prolonged hypoxia. In epinephrine and norepinephrine infused fetuses, blood glucose and plasma glucagon concentrations were increased significantly, whereas plasma insulin concentrations were decreased significantly. Norepinephrine and epinephrine infusions increased IGFBP-1 levels significantly (2- to 5-fold) in fetal plasma within 8-12 h, and the time course pattern of elevation of plasma IGFBP-1 levels was similar to that observed in prolonged hypoxia. After 24 h of either norepinephrine or epinephrine infusion, IGFBP-1 mRNA levels in the liver of fetuses were increased significantly (5- to 7-fold) compared to those of vehicle infused fetuses. IGFBP-2, -3, and -4 levels in fetal plasma were not affected by either infusion, nor were IGFBP-2 mRNA levels in fetal liver and kidney.(ABSTRACT TRUNCATED AT 400 WORDS)

Variation at the apo AI/CIII/AIV gene complex is associated with elevated plasma levels of apo CIII.

A number of studies have reported that a variant allele (S2) of the apo AI/CIII/AIV complex is associated with high plasma lipid levels in some populations and furthermore that the frequency of this allele is 2-5-fold higher in patient groups with premature coronary heart disease compared to control groups. This study shows in the healthy "English" population that the S2 allele is associated with elevated plasma apo CIII levels but not with low apo AI levels. In addition, it shows that the allele is associated with elevated plasma levels of apo B in men. Regression analysis shows in both men and women that apo CIII levels are positively correlated with plasma triglyceride levels and moreover that they are a stronger predictor of this parameter than apo AI, B or AIV. Apo CIII levels are also an independent predictor of total plasma cholesterol and HDL-cholesterol levels in males and females, respectively. Together these data suggest that a genetic predisposition to develop elevated plasma levels of apo CIII, alone or in combination with elevated plasma apo AIV levels, is the primary defect responsible for the association of the S2 allele with hyperlipidemia and/or premature CHD.

Fetal endocrine responses to prolonged reduced uterine blood flow are altered following bilateral sectioning of the carotid sinus and vagus nerves.

The present study examines the effect of carotid sinus/vagosympathetic denervation on fetal endocrine responses to prolonged reduced uterine blood flow (RUBF). Fetal sheep had vascular catheters inserted following bilateral sectioning of the carotid sinus and vagus nerves (denervated, n = 7) or sham denervation (intact, n = 7). Uterine blood flow was mechanically restricted at 126.1 +/- 0.7 days (mean +/- S.E.M.) for 24 h, decreasing arterial oxygen saturation by 47.3 +/- 2.6% (P < 0.01). Fetal plasma samples were obtained at -1, 3, 6, 12 and 24 h for subsequent analyses of arginine vasopressin (AVP), angiotensin II and catecholamines. The AVP response to prolonged RUBF was markedly attenuated in denervated fetuses (15.6 +/- 3.6 to 34.9 +/- 6.0 pg/ml) when compared with intact (10.0 +/- 1.4 to 127.3 +/- 28.4 pg/ml). In contrast, intact fetuses demonstrated no change in plasma angiotensin II concentrations with RUBF whereas denervated fetuses demonstrated a marked increase from 47.5 +/- 18.9 to 128.7 +/- 34.2 pg/ml. The norepinephrine and epinephrine responses to prolonged RUBF were attenuated in denervated fetuses (950.1 +/- 308.9 and 155.8 +/- 58.5 to 1268.3 +/- 474.6 and 290.6 +/- 160.2 pg/ml respectively) when compared with intact (1558.3 +/- 384.4 and 547.3 +/- 304.7 pg/ml to 3289.2 +/- 1219.8 and 896.8 +/- 467.8 pg/ml respectively). These results support a role for the peripheral chemoreceptors in mediating fetal endocrine responses to prolonged RUBF, which may in part lead to the altered cardiovascular responses observed in denervated fetuses under these conditions.

Behavioral activity during prolonged hypoxemia in fetal sheep.

Experiments were conducted in unanesthetized, chronically catheterized pregnant sheep to determine the fetal behavioral response to prolonged hypoxemia produced by restricting uterine blood flow. Uterine blood flow was reduced by adjusting a vascular occluder placed around the maternal common internal iliac artery to decrease fetal arterial O2 content from 6.1 +/- 0.3 to 4.1 +/- 0.3 ml/dl for 48 h. Associated with the decrease in fetal O2 content, there was a slight increase in fetal arterial PCO2 and decrease in pH, which were both transient. There was an initial inhibition of both fetal breathing movements and eye movements but no change in the pattern of electrocortical activity. After this initial inhibition there was a return to normal incidence of both fetal breathing movements and eye movements by 16 h of the prolonged hypoxemia. These studies indicate that the chronically catheterized sheep fetus is able to adapt behaviorally to a prolonged decrease in arterial O2 content secondary to the restriction of uterine blood flow.

Basis for the selective reduction of pulmonary vascular resistance in humans during infusion of adenosine.

The objective of this study was to demonstrate the basis for the selective reduction of pulmonary vascular resistance by intravenous infusion of adenosine. Secondary objectives of the study were to determine the rate of central infusion of adenosine at which the nucleoside appears in the systemic circulation and to relate this to hemodynamic events. Plasma concentrations of adenosine in the right and left atria were measured during peripheral (5 patients) and central (12 patients) infusions of adenosine in adults with normal pulmonary arterial pressures undergoing coronary artery bypass surgery. The hemodynamic effects of central (right ventricle) infusion of adenosine were also examined. The extraction of adenosine across the pulmonary vascular bed was found to be 73.6 +/- 4.8%. The mean maximal decrease in pulmonary vascular resistance index, 48.8 +/- 9.6%, occurred at an adenosine infusion rate of 30 micrograms.kg-1.min-1, whereas the systemic vascular resistance index remained unchanged. Thus, adenosine, administered centrally in anesthetized patients with normal pulmonary vascular resistances, selectively lower pulmonary vascular resistance. The basis for this selective effect is the substantial extraction of adenosine during passage through the pulmonary vascular bed.

The adenosine A(1)-receptor antagonist 8-CPT reverses ethanol-induced inhibition of fetal breathing movements.

Administration of either ethanol or adenosine inhibits fetal breathing movements (FBM), eye movements, and low-voltage electrocortical activity (LV ECoG). The concentration of adenosine in ovine fetal cerebral extracellular fluid increases during ethanol-induced inhibition of FBM. The purpose of this study was to determine the effect of a selective adenosine A(1)-receptor antagonist, 8-cyclopentyltheophylline (8-CPT) on the incidence of FBM during ethanol exposure. After a 2-h control period, seven pregnant ewes received a 1-h intravenous infusion of ethanol (1 g/kg maternal body wt), followed 1 h later by a 2-h fetal intravenous infusion of either 8-CPT (3.78 +/- 0.08 microg. kg(-1). min(-1)) or vehicle. Ethanol reduced the incidence of FBM from 44.0 +/- 10.4 to 2.7 +/- 1.3% (P < 0.05) and 51.2 +/- 7.6 to 11.9 +/- 5.0% (P < 0.05) in fetuses destined to receive 8-CPT or vehicle, respectively. In the vehicle group, FBM remained suppressed for 7 h. In contrast, during the first hour of 8-CPT infusion, FBM returned to baseline (31 +/- 11%) and was not different from control throughout the rest of the experiment. Ethanol also decreased the incidence of both low-voltage electrocortical activity and eye movements, but there were no differences in the incidences of these behavioral parameters between the 8-CPT and vehicle groups throughout the experiment. These data are consistent with the hypothesis that adenosine, acting via A(1) receptors, may play a role in the mechanism of ethanol-induced inhibition of FBM.

Increased cerebral extracellular adenosine and decreased PGE2 during ethanol-induced inhibition of FBM.

Adenosine and PGE2 are neuromodulators, both of which inhibit fetal breathing movements (FBM). Although circulating PGE2 has been implicated as a mediator of ethanol-induced inhibition of FBM in the late-gestation ovine fetus, a role for adenosine has not been examined. The objective of this study was to determine the effect of maternal ethanol infusion on ovine fetal cerebral extracellular fluid adenosine and PGE2 concentrations by using in utero microdialysis and to relate any changes to ethanol-induced inhibition of FBM. Dialysate samples were obtained from the fetal parietal cortex over 70 h after surgery to determine steady-state extracellular fluid adenosine and PGE2 concentrations. On each of postoperative days 3 and 4, after a 2-h baseline period, ewes received a 1-h infusion of ethanol (1 g/kg maternal body wt) or an equivalent volume of saline, and the fetus was monitored for a further 11 h with 30-min dialysate samples collected throughout. Immediately after surgery, dialysate PGE2 and adenosine concentrations were 3.7 +/- 0.7 and 296 +/- 127 nM, respectively. PGE2 did not change over the 70 h, whereas adenosine decreased to 59 +/- 14 nM (P < 0.05) at 4 h and then remained unchanged. Ethanol decreased dialysate PGE2 concentration for 2 h (3.3 +/- 0.3 to 1.9 +/- 0.4 nM; P < 0.05) and increased adenosine concentration for 6 h (87 +/- 13 to a maximum of 252 +/- 59 nM, P < 0.05). Ethanol decreased FBM incidence from 47 +/- 7 to 16 +/- 5% (P < 0.01) for 8 h. Saline infusion did not change dialysate adenosine or PGE2 concentrations or FBM incidence. These data are consistent with the hypothesis that fetal cerebral adenosine, and not PGE2, is the primary mediator of ethanol-induced inhibition of FBM at 123 days of gestation in sheep.

Sagittal sinus blood flow in the ovine fetus as a continuous measure of cerebral blood flow: relationship to behavioural state activity.

Superior sagittal sinus blood flow (Q(ss)) was studied over a 6-h period in nine chronically catheterized fetal sheep as a continuous measure of cerebral blood flow to determine the change in blood flow values and in measures of blood flow variability in relation to behavioural state activity. Mean Q(ss) was increased during the low voltage (LV)/rapid eye movement (REM) state compared to the high voltage (HV)/NREM state by approximately 25%, and was further increased during periods of LV/REM with fetal breathing movements. The increase in Q(ss) was abrupt and began at the transition to LV/REM, with the rate of change 2-fold greater than that during transition to HV/NREM, where the decrease in Q(ss) was gradual and began prior to the evident state change. Q(ss) showed considerable fluctuation, which tended to be greater during the HV/NREM state compared to the LV/REM state when analyzed using measures of longer term variability. Q(ss) thus provides for a continuous measure of cerebral blood flow in the ovine fetus, with the approximately 25% increase with change from the HV/NREM to LV/REM state similar to that previously reported using radioactive microspheres. The abrupt increase in Q(ss) at the transition to LV/REM versus the gradual decrease in Q(ss) before transition to HV/NREM would suggest that the state-related change in brain blood flow is better linked to the presence of the LV electrocorticogram and favours its active generation.

Patellar tracking measurement in the normal knee.

Eleven fresh frozen cadaveric knee specimens were mounted in a knee kinematics test device, and normal patellar movements were evaluated with use of an external device for direct measurement of patellar movements. The effects of four different measurement conditions were assessed through alteration of one condition and determination of its effect on patellar kinematics with the use of six specimens. The four conditions included (a) change of the measuring axis from an axis parallel to the central axis of the femur (femoral axis) to one parallel to the central axis of the tibia (tibial axis), (b) rotation of the femoral axis internally 6 degrees, (c) change of the direction of the quadriceps force from parallel to the mechanical line of the lower extremity to a direction parallel to the femoral shaft, and (d) increase of the magnitude of the quadriceps force from 111 to 500 N. During knee flexion, the patella shifted laterally after a slight initial medial shift, tilted laterally from midflexion to 90 degrees, and gradually rotated medially. The patellar shift relative to the tibial axis appeared to be more medial than the shift measured relative to the femoral axis; the discrepancy was caused by the valgus position of the tibia relative to the femur. Changing the rotational angle of the femoral axis artificially changed the patellar position. Varying the direction of the quadriceps within the narrow range and increasing the quadriceps force did not affect patellar movements.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular and metabolic responses to intermittent umbilical cord occlusion in the preterm ovine fetus.

OBJECTIVE: To determine the cardiovascular and metabolic responses to umbilical cord occlusion in the preterm ovine fetus and the impact of repetitive intermittent insults over a 4-day period. METHODS: Repetitive umbilical cord occlusions (experimental group, n = 7; control group, n = 7) were performed daily (112-115 days' gestation, term = 147 days). Mean arterial pressure (MAP), fetal heart rate (FHR), and FHR variation were monitored, and arterial blood was sampled at predetermined intervals. RESULTS: During umbilical cord occlusions, arterial oxygen pressure (PaO2) (approximately 17 mmHg) and glucose (approximately 0.3) millimoles per liter (mmol/L) fell and arterial carbon dioxide pressure (approximately 8 mmHg) rose (P < .01) to a similar extent on days 1 and 4. Umbilical cord occlusion produced a rise in lactate over the course of successive umbilical cord occlusions each day, the magnitude of which tended to be reduced by day 4 (0.3 +/- 0.1 versus 0.6 +/- 0.1 mmol/L). Control hour FHR and MAP were unaltered over the 4 days, but the delta (delta) FHR to delta PaO2 ratio during umbilical cord occlusions was less on day 4 than on day 1 (6.0 +/- 0.4 versus 10.9 +/- 1.5 beats per minute/mmHg; P < .01). During occlusion hours, high FHR variation episodes, as a measure of fetal activity, were reduced (14.6 +/- 1.5 versus 4.2 +/- 1.3 min/h; P < .01), whereas the reduction in short-term (7.4 +/- 0.7 to 5.8 +/- 0.6 milliseconds; P < .05) and long-term (34.9 +/- 2.7 to 30.0 +/- 0.6 milliseconds; P < .05) FHR variation reached significance only on day 4. CONCLUSION: The increase in lactate and reduced high-FHR variation episodes over successive umbilical cord occlusions may affect fetal growth and development. Furthermore, repeated umbilical cord occlusions over several days alter the preterm FHR response to subsequent stresses, suggesting an altered chemoreflex response.

Femoral rotational alignment, based on the anteroposterior axis, in total knee arthroplasty in a valgus knee. A technical note.

The landmarks used to achieve correct rotational alignment of the femoral component in total knee arthroplasty may be indistinguishable or unreliable in the distal architecture of a valgus knee. Five observers identified the anteroposterior axis, the posterior condylar axis, and the transepicondylar axis in thirty cadaveric femora to determine the reliability of the use of each axis in the operative setting. In addition, radiographs were made of the distal aspect of each femur, the axes were constructed, and the angles were measured and compared with the visual measurements made by the observers. A line drawn perpendicular to the anteroposterior axis consistently approximated 4 degrees of external rotation relative to the posterior condylar surfaces. The transepicondylar axis was more difficult to define and was not as accurate. The radiographic results were similar to the visual results, but the standard deviations for the former were less than those for the latter. The anteroposterior axis appears to be a reliable landmark for rotational alignment of the femoral component in a valgus knee.

Integrating genetics and genomics to identify new leads for the control of Eimeria spp.

Eimerian parasites display a biologically interesting range of phenotypic variation. In addition to a wide spectrum of drug-resistance phenotypes that are expressed similarly by many other parasites, the Eimeria spp. present some unique phenotypes. For example, unique lines of Eimeria spp. include those selected for growth in the chorioallantoic membrane of the embryonating hens egg or for faster growth (precocious development) in the mature host. The many laboratory-derived egg-adapted or precocious lines also share a phenotype of a marked attenuation of virulence, the basis of which is different as a consequence of the in ovo or in vivo selection procedures used. Of current interest is the fact that some wild-type populations of Eimeria maxima are characterized by an ability to induce protective immunity that is strain-specific. The molecular basis of phenotypes that define Eimeria spp. is now increasingly amenable to investigation, both through technical improvements in genetic linkage studies and the availability of a comprehensive genome sequence for the caecal parasite E. tenella. The most exciting phenotype in the context of vaccination and the development of new vaccines is the trait of strain-specific immunity associated with E. maxima. Recent work in this laboratory has shown that infection of two inbred lines of White Leghorn chickens with the W strain of E. maxima leads to complete protection to challenge with the homologous parasite, but to complete escape of the heterologous H strain, i.e. the W strain induces an exquisitely strain-specific protective immune response with respect to the H strain. This dichotomy of survival in the face of immune-mediated killing has been examined further and, notably, mating between a drug-resistant W strain and a drug-sensitive H strain leads to recombination between the genetic loci responsible for the specificity of protective immunity and resistance to the anticoccidial drug robenidine. Such a finding opens the way forward for genetic mapping of the loci responsible for the induction of protective immunity and integration with the genome sequencing efforts.

Placental and fetal hepatic growth are selectively inhibited by prolonged reductions of uterine blood flow in pregnant sheep.

Experiments were conducted in eight pregnant sheep to determine the effect on fetal growth of mechanical restriction of uterine blood flow (RUBF) between 120 days and 134 days gestation. Uterine blood flow measured in the middle uterine arteries was 40% less in RUBF animals compared with control animals at the end of the experimental period. There was no change in fetal blood gases, bodyweights, or organ weights between the two groups of animals. The rate of DNA synthesis in the right lobe of the liver was significantly less in RUBF animals (581 +/- 34 dpm micrograms-1 DNA) compared with control animals (845 +/- 44 dpm microgram-1 DNA). There was no difference in the rate of DNA synthesis in the left lobe of the liver or in any of the other organs examined. Autoradiographic examination of the placental cotyledons demonstrated that most DNA synthesis in the placenta was occurring in fetal trophoblastic cells and there was a 40% reduction in the nuclear-labelling index of placental trophoblast cells. These studies show that mild mechanical reductions in uterine blood flow in pregnant sheep results in the selective inhibition of growth in the right lobe of the fetal liver and the placental trophoblastic cells. The mechanism underlying this close association remains to be determined.

Unnecessary hospitalization of Medicare patients in Ohio. A preliminary profile.

Peer review organizations (PRO) review the health care given to Medicare beneficiaries. If a PRO determines that a hospital admission was unnecessary, the hospital is not reimbursed for the medical care and the case is "denied." The average hospital denial rate on Ohio is 2%; however, the denial rate for hospital admissions of one day or less is 7.5%. An analysis of hospitals and diagnoses for one-day hospital admission denials was performed, showing that urban hospitals and disorders of the circulatory and digestive systems predominate. The inappropriate utilization of health care resources costs millions of dollars per year in Ohio and could be costing the nation billions of dollars. There is an urgent need to research why resources are used less effectively by some hospitals and for some diseases.

Sexuality and pregnancy. A prospective study.

The normative changes in various sexual variables in pregnancy remain controversial. Much of the data available have been derived from retrospective and subjective, prospective investigations. The present prospective study indicated decreases in sexual enjoyment, coital frequency and orgasm as pregnancy progressed. A midtrimester increase in sexual desire preceding a progressive decrease was evident. Overall sexual satisfaction was correlated with feeling happy about being pregnant, feeling more attractive in late pregnancy than before pregnancy and experiencing orgasm. Anticipatory guidance and informed counsel regarding sexual changes in pregnancy should be provided to help pregnant patients and their husbands adapt to the pregnancy and enhance their marital bonds.

Sarcoidosis in a pregnant woman.

Sarcoidosis, a rare multisystem disease, often occurs in women of childbearing age. The disease, which may be improved or exacerbated by pregnancy, presents unique considerations to the anesthesiologist. These considerations are illustrated by the case presented here of complicated sarcoidosis in a parturient who underwent cesarean section.

Effects of trendelenburg position and positive intrathoracic pressure on internal jugular vein cross-sectional area in anesthetized children.

STUDY OBJECTIVE: To compare the cross-sectional area (in cm(2)) of the left internal jugular vein (LIJV) and right internal jugular vein (RIJV) in anesthetized children, and measure the response to the Trendelenburg tilt position (TBRG) and a positive inspiratory pressure hold. DESIGN: Prospective, nonrandomized study. SETTING: University medical center. PATIENTS: 45 ASA physical status I and II children, ages 6 months to 8 years, undergoing general anesthesia and mechanical ventilation. INTERVENTIONS: The cross-sectional area of both internal jugular veins was measured with a 5-MHz, two-dimensional surface transducer, at the level of the cricoid cartilage. Three measurements were obtained: 1) with the patient supine, 2) during a 10-second breath-hold with a positive inspiratory pressure (PIP) of 20 cm H(2)O, and 3) with the patient at 20 degrees TBRG. Data were analyzed with two-way analysis of variance (ANOVA) and Student-Newman-Keuls test, with a p < 0.05 considered significant. MEASUREMENTS AND MAIN RESULTS: In supine patients, the cross-sectional area of the RIJV was larger than the LIJV in 31 patients (69%), and equal or smaller in 14 patients (31%) (0.80 +/- 0.38 vs. 0.59 +/- 0.22; p = 0.002). A PIP hold, but not TBRG, significantly dilated the RIJV (0.8 +/- 0.38 at baseline vs. 0.93 +/- 0.42 with TBRG; p = not significant vs. 1.1 +/- 0.46 with PIP; p < 0.05), whereas neither maneuver was effective with the LIJV. CONCLUSION: The cross-sectional area of the RIJV is often greater than the LIJV; the TBRG was not effective to increase the cross-sectional area of the internal jugular veins, and only a PIP hold increased significantly the cross-sectional area of the RIJV. In this study, the LIJV appeared of smaller size and less compliant compared with the RIJV.