Changes in the rhizosphere of metal-accumulating plants evidenced by chemical extractants

The plants Salix viminalis L. (common osier) and Thlaspi caerulescens J. Presl & C. Presl have been studied often because of their high potential to extract heavy metals from soils. The soil properties favoring this phytoextraction are not yet fully known. In this study we compared three frequently used single-extracting agents (NaNO3, diethylenetriaminepentaacetic acid [DTPA], and ethylenediaminetetra-acetic acid [EDTA]) with a sequential extraction procedure to describe changes in the different Cd, Cu, and Zn pools in the rhizosphere of S. viminalis and T. caerulescens grown on calcareous and acidic Swiss soils in a pot experiment. The sequential extraction was used to assess the chemical affinities of these heavy metals (HM) in the soil whereas the single extractants were used for estimating the bioavailable HM pools in the soils. Cadmium depletion in several pools was most apparent in the acidic soil, with a significant decrease observed in the NaNO3-, DTPA-, and EDTA-extractable fractions following T. caerulescens growth compared with control pots. The sequential extraction showed that most Cd extracted by the plant from the acidic soil originated from the organic pool, which implies that heavy metals bound to organic matter may constitute a significant part of the bioavailable Cd pool in soils. In the calcareous soil only a small amount of Cd was taken up by T. caerulescens, and this came mainly from the carbonate-bound fraction. This study shows that T. caerulescens, and to a lesser extent S. viminalis, can alter the heavy metal distribution in different soil pools within 90 d.

Trace metal leaching through a soil-grassland system after sewage sludge application

To determine whether sludge applications to soil would lead in the short term to toxicity to plants and trace metal leaching to ground water, we studied the fate of some trace and major elements in a brown soil-meadow system just after repeated sewage sludge applications. The main pathways were quantified over a 37-mo period with undisturbed monolith lysimeters including two controls, four lysimeters treated with 3 x 100 m3 ha-1, and four with 3 x 400 m3 ha-1 of sewage sludge. In drainage waters the effect was limited in time and, in the case of NO3-N and Cl, delayed by 1 to 4 mo and lasted several months before returning to background conditions. Nickel and Cu concentrations in solution increased also after sludge application and had not return to background conditions after 20 mo. Trace metal concentrations did not reach toxic levels in herbage and N, Cu, Cd, and Zn concentrations were correlated with the first sludge input only. Calculated over a 37-mo period, total element output was significantly increased for Ca, NO3-N, and Ni only, because of the time-dependent response to sludge application and high variability between replicates. Output was maximal for Cd, with 1.5% of total input for the 100 m3 ha-1 treatment. Particulate matter in drainage water accounted for an average of 20% of trace metal leaching. The main long-term risk was the rapid increase in trace metal concentrations in the topsoil, which may eventually lead to toxic levels in herbage.

Neopterin as a marker of immunostimulation: an investigation in anaesthetic workplaces

Personnel working in operating theatres and recovery rooms are exposed to a variety of noxious substances. The results of studies of the effects of occupational exposure on immune parameters are conflicting. Neopterin is an acknowledged marker of immunostimulation. Urinary neopterin levels of 58 anaesthetists and anaesthetic nurses were measured over a 3-week period. Neopterin analyses were performed using high performance liquid chromatography. Neopterin levels were within the normal range for all subjects. Younger subjects (aged < or = 35 years) had significantly higher urinary neopterin concentrations than older subjects (aged > 35 years). The present study is the first to investigate the influence of anaesthetic exposure on neopterin levels. No evidence of immunostimulation was found.

Monitoring pollution by proton-transfer-reaction mass spectrometry during paediatric anaesthesia with positive pressure ventilation via the laryngeal mask airway or uncuffed tracheal tube

Twenty children aged 2-66 months were randomly allocated for airway management with either the laryngeal mask airway or uncuffed tracheal tube using intermittent positive pressure ventilation with a tidal volume of 8 ml.kg-1 and a respiratory rate adjusted to maintain end-expiratory carbon dioxide concentration at 5.3 kPa. Induction was with fentanyl/propofol and maintenance was with sevoflurane 2.5% in oxygen/air. The airway device was removed when the patients were awake and the patients were transferred to the postanaesthesia care unit 10 min later. Air was sampled from a point 1.5 m above the floor at a location remote from the ventilation outlet and analysed using a proton-transfer-reaction mass spectrometer capable of continuous trace gas analysis at the parts per billion volume (ppbv) level. The concentration of sevoflurane was recorded every minute during three consecutive phases: for 5 min before the introduction of sevoflurane (background); after introduction of sevoflurane until removal of the airway device (intra-operative); and every minute after removal until the concentration returned to background levels. Median (interquartile range [range]) intra-operative sevoflurane concentrations were 200-400 times higher than background values for the laryngeal mask airway 1 (1-2 [0-3]) ppbv vs. 404 (278-523 [83-983]) ppbv, respectively, and the tracheal tube 2 (1-3 [0-5]) ppbv vs. 396 (204-589 [107-1735]) ppbv (both p < 0.0001), and returned to background values within 5 min of removal. There were no differences in sevoflurane concentration between devices intra-operatively or after removal. The performance of the proton-transfer-reaction mass spectrometer was identical at the start and end of the 30-day study. We conclude that peri-operative sevoflurane concentration in a modern operating theatre is similar for the laryngeal mask airway and the uncuffed tracheal tube in paediatric patients receiving intermittent positive pressure ventilation. Intra-operative sevoflurane concentrations are five times lower than occupational safety limit requirements, and 1000 times lower 5 min after removal of the airway device with the patient awake. The proton-transfer-reaction mass spectrometer has potential for monitoring air quality in the operating theatre.

Augmented spontaneous breathing and pulmonary gas exchange during pneumoperitoneum

BACKGROUND AND OBJECTIVE

Ventilation of the lungs with positive end-expiratory pressure during pneumoperitoneum has been shown to improve the arterial partial pressure of oxygen. The implications of spontaneous breathing on pulmonary gas exchange remain unknown in this setting. We therefore sought to examine the influence of pressure-support ventilation with spontaneous breathing on gas exchange during simulated laparoscopy.

METHODS

Ten pigs were subjected to pneumoperitoneum at a pressure of 15 cmH2O. Animals received, in a random order, pressure-support and pressure-controlled ventilation for 60 min per mode. Inert gas and haemodynamic measurements were performed before changing to a subsequent mode.

RESULTS

Pressure-support ventilation was more efficient than pressure-controlled ventilation regarding perfusion of normal V(A)/Q lung areas (78 +/- 4% vs. 72 +/- 5%) (P < 0.05), alveolar-arterial partial pressure of oxygen difference (9.73 +/- 1.3 vs. 11.2 +/- 1.2 kPa) and arterial partial pressure of oxygen (14.93 +/- 1.6 vs. 13.7 +/- 2.0 kPa) (P < 0.05).

CONCLUSIONS

Pressure-support ventilation resulted in significantly better gas exchange than pressure-controlled ventilation in this model of simulated laparoscopy.

Separation quality of a geometric ratchet

We consider an experimentally relevant model of a geometric ratchet in which particles undergo drift and diffusive motion in a two-dimensional periodic array of obstacles, and which is used for the continuous separation of particles subject to different forces. The macroscopic drift velocity and diffusion tensor are calculated by a Monte Carlo simulation and by a master-equation approach, using the corresponding microscopic quantities and the shape of the obstacles as input. We define a measure of separation quality and investigate its dependence on the applied force and the shape of the obstacles.

The feasibility of transesophageal echocardiograph-guided right and left ventricular oximetry in hemodynamically stable patients undergoing coronary artery bypass grafting

There are no techniques available for continuous noninvasive measurement of the oxygen saturation of blood flowing through the heart. We assessed the feasibility and accuracy of transesophageal echocardiograph (TEE)-guided left ventricular (SpO2 LV) and right ventricular (SpO2 RV) oximetry. Twenty hemodynamically stable, well-oxygenated anesthetized patients (ASA physical status III, aged 51-75 yr) undergoing coronary artery bypass grafting were studied. A TEE probe was modified by attaching a single-use pediatric reflectance pulse oximeter just proximal to the ultrasound transducer. The TEE probe was directed toward the LV by using the transgastric mid-short axis view or toward the RV by using the transgastric RV inflow view, in random order. Readings were taken every 30 s for 10 min during a hemodynamically stable period of anesthesia. Simultaneous blood samples were taken from the radial artery and pulmonary artery to determine arterial oxygen saturation (SaO2) and mixed venous oxygen saturation (SvO2), respectively. During SpO2 LV readings, simultaneous finger pulse oximetry (SpO2 finger) was also recorded. SpO2 LV was feasible in 20 of 20 patients, and SpO2 RV was feasible in 19 of 20 patients. The mean +/- SD (range) oxygen saturation for each method was the following: SpO2 LV, 98.7% +/- 0.6% (97%-100%); SaO2, 98.7% +/- 0.6% (96.6%-99.4%); SpO2 finger, 98.1% +/- 1.2% (97%-100%); SpO2 RV, 73.9% +/- 4.7% (64%-85%); and SvO2, 74.5% +/- 4.4% (66.8%-82.6%). SpO2 LV agreed closely with SaO2 (mean difference, 0.072%). SpO2 RV agreed closely with SvO2 (mean difference, 0.65%). SpO2 LV agreed more closely with SaO2 than finger oximetry (mean difference, -0.072 vs -0.692). TEE-guided SpO2 LV and SpO2 RV are feasible in hemodynamically stable anesthetized patients and provide similar readings to arterial and mixed venous blood samples. The technique merits further investigation.

IMPLICATIONS

Transesophageal echocardiograph-guided left and right ventricular oximetry is feasible in hemodynamically stable anesthetized patients and provides similar readings to arterial and mixed venous blood samples.

Exercise and cytokines with particular focus on muscle-derived IL-6

Exercise induces increased circulating levels of a number of cytokines. Thus, increased plasma levels of tumour necrosis factor (TNF)-alpha, interleukin (IL-1) beta, IL-1 receptor antagonist (IL-1ra), TNF-receptors (TNF-R), IL-10, IL-8, and macrophage inflammatory protein (MIP)-1 are found after strenuous exercise. The concentration of IL-6 increases up to 100 fold after a marathon race. Recently, it has been demonstrated that IL-6 is produced locally in contracting skeletal muscles and that the net release from the muscle can account for the exercise-induced increase in arterial IL-6 concentration. IL-6 more than any other cytokine is produced in large amounts in response to exercise. It is produced locally in the skeletal muscle in response to exercise, and IL-6 is known to induce hepatic glucose-output and to induce lipolysis. This indicates that IL-6 may represent an important link between contracting skeletal muscles and exercise-related metabolic changes.

Mechanical closure of the vocal cords with the laryngeal mask airway ProSeal

We report a case of mechanical closure of the vocal cords with the laryngeal mask airway ProSeal (PLMA) in an anaesthetized, paralysed 59-yr-old, 88 kg female undergoing lower-limb vascular surgery. Near-complete airway obstruction developed after a size-5 PLMA was inserted and the cuff inflated with 20 ml of air. Fibreoptic inspection revealed that the PLMA was correctly positioned, but the vocal cords were closed. Withdrawal of air from the cuff and/or moving the head and neck into the sniffing position resolved this problem.

Educational preparedness for physical therapists and occupational therapists in burn care

The background of physical therapy (PT) and occupational therapy (OT) students in burn care training may be variable during their professional education. The purpose of this study was to evaluate whether professional programs in PT and OT are meeting the burn care educational needs of their students. PTs and OTs currently practicing in burn care were asked to give their opinion of the most important curricular topics related to burn care, report their perception of their own entry-level preparedness for burn care, recount therapy interns preparation for burn care internships, and recommend topics that should be included in a therapy program burn care curriculum. Therapists felt prepared in basic sciences and somewhat prepared in specific burn care practice topics. Study participants felt more prepared for burn practice if they completed an internship in burn care. Enhancing content on burn-related treatment interventions was the most common suggestion for curricular revision.

Reliability of epigastric auscultation to detect gastric insufflation

BACKGROUND

We studied the reliability of epigastric auscultation to detect gastric insufflation in 30 anaesthetized, paralysed intubated patients.

METHODS

A 16FG gastric tube was positioned with the tip in the mid-oesophagus with the proximal end attached to an injection port with a one-way valve. Four observers participated in the study. Observers were paired and each pair studied 15 patients. Each patient underwent four test sequences in random order, two by each observer. Each test sequence comprised one observer injecting different volumes of air (0.25 ml, 0.5 ml, 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 10 ml, 15 ml and 0 ml as a control) in random order whilst the second blinded observer listened with a stethoscope over the epigastrium. Each randomized volume was injected rapidly at 5 s intervals for 1 min. The number of injections required to detect air entering the stomach was recorded. The stomach was deflated between each test sequence.

RESULTS

To detect air entering the stomach with 95% confidence, 11 injections were required for 0.25 ml; 7 for 0.5 ml; 3 for 1 ml; 2 for 2 ml and 3 ml, and I for > or =4 ml. The mean (range) inter- and intraobserver reliability was 0.73 (0.71-0.75) and 0.76 (0.76-0.89), respectively. The incidence of false positives was 21% (25/120) and the incidence of false negatives was 10% (103/1080), making the specificity and sensitivity 79% and 91%, respectively.

CONCLUSIONS

We conclude that epigastric auscultation can detect gastric insufflation of 0.25 ml air after 11 breaths and > or = 4 ml air after one breath with 95% confidence. Inter- and intraobserver reliability is moderate to excellent. Epigastric auscultation should be repeated to reduce the risk of false positives.

Transcriptional activation of the IL-6 gene in human contracting skeletal muscle: influence of muscle glycogen content

In humans, the plasma interleukin 6 (IL-6) concentration increases dramatically during low-intensity exercise. Measurements across the working limb indicate that skeletal muscle is the source of IL-6 production. To determine whether energy availability influences the regulation of IL-6 expression during prolonged exercise, six male subjects completed two trials consisting of 180 min of two-legged dynamic knee extensor with either normal or low (~60% of control) pre-exercise muscle glycogen levels. Increases in plasma IL-6 during exercise were significantly higher (P<0.05) in the low-glycogen (16-fold) trial verses the control (10-fold) trial. Transcriptional activation of the IL-6 gene in skeletal muscle was also higher in the low-glycogen trial; it increased by about 40-fold after 90 min of exercise and about 60-fold after 180 min of exercise. Muscle IL-6 mRNA followed a similar but delayed pattern, increasing by more than 100-fold in the low-glycogen trial and by about 30-fold in the control trial. These data demonstrate that exercise activates transcription of the IL-6 gene in working skeletal muscle, a response that is dramatically enhanced when glycogen levels are low. These findings also support the hypothesis that IL-6 may be produced by contracting myofibers when glycogen levels become critically low as a means of signaling the liver to increase glucose production.

Isoflurane and sevoflurane anesthesia in pigs with a preexistent gas exchange defect

BACKGROUND

Decreased arterial partial pressure of oxygen (PaO2) during volatile anesthesia is well-known. Halothane has been examined with the multiple inert gas elimination technique and has been shown to alter the distribution of pulmonary blood flow and thus PaO2. The effects of isoflurane and sevoflurane on pulmonary gas exchange remain unknown. The authors hypothesized that sevoflurane with a relatively high minimum alveolar concentration (MAC) would result in significantly more gas exchange disturbances in comparison with isoflurane or control.

METHODS

This study was performed in a porcine model with an air pneumoperitoneum that generates a reproducible gas exchange defect. After a baseline measurement of pulmonary gas exchange (multiple inert gas elimination technique) during propofol anesthesia, 21 pigs were randomly assigned to three groups of seven animals each. One group received isoflurane anesthesia, one group received sevoflurane anesthesia, and one group was continued on propofol anesthesia (control). After 30 min of volatile anesthesia at 1 MAC or propofol anesthesia, a second measurement (multiple inert gas elimination technique) was performed.

RESULTS

At the second measurement, inert gas shunt was 15 +/- 3% (mean +/- SD) during sevoflurane anesthesia versus 9 +/- 1% during propofol anesthesia (P = 0.02). Blood flow to normal ventilation/perfusion (V(A)/Q) lung areas was 83 +/- 5% during sevoflurane anesthesia versus 89 +/- 1% during propofol anesthesia (P = 0.04). This resulted in a PaO2 of 88 +/- 11 mmHg during sevoflurane anesthesia versus 102 +/- 15 mmHg during propofol anesthesia (P = 0.04). Inert gas and blood gas variables during isoflurane anesthesia did not differ significantly from those obtained during propofol anesthesia.

CONCLUSIONS

In pigs with an already existent gas exchange defect, sevoflurane anesthesia but not isoflurane anesthesia causes significantly more gas exchange disturbances than propofol anesthesia does.

Positive pressure ventilation with the ProSeal versus classic laryngeal mask airway: a randomized, crossover study of healthy female patients

IMPLICATIONS

The ProSeal and classic laryngeal mask airways are equally effective ventilatory devices in healthy female patients at tidal volumes of 8 and 12 mL/kg with the cuff semi- or fully inflated, but leakage of small volumes of air from the mouth occurs more frequently with the laryngeal mask airway.

Bone mineral density in women and men with early rheumatoid arthritis

OBJECTIVE

To study bone mineral density (BMD) in patients with early rheumatoid arthritis.

METHODS

Dual x-ray absorptiometry was performed in 227 patients, 149 women and 78 men, with rheumatoid arthritis (RA) of no more than 12 months duration.

RESULTS

Women, as well as men above 60 years of age, had a BMD at spine and hip comparable with age and sex matched reference populations. Men younger than 60 years had a tendency to lower BMD. Although the proportion of female patients with osteoporosis was not higher than in the reference, population the proportion of patients with reduced bone mass was increased, and this was found also in men. There was no significant association between BMD and disease duration, disease activity or disability.

CONCLUSION

Untreated patients with early RA have a BMD in spine and hip not significantly different from that of normal reference populations. However, an increased number of the patients had reduced bone mass already at disease onset.

Effects of two frequencies of walking on cardiovascular risk factor reduction in Mexican American women

The beneficial effects of moderate-intensity exercise on cardiorespiratory fitness and body composition are well documented, with the greatest health benefits reported in sedentary individuals who engage in moderate levels of exercise. The published literature contains no quantification of the threshold of lower limits of beneficial exercise or estimates of benefits derived from lower exercise levels. The specific aim of this study was to compare the effects of two walking frequencies, holding intensity and duration constant, on blood lipids, body composition, and exercise maintenance regimens of Mexican American women. A quasi-experimental design, with two treatment groups and one comparison group, was used to explore the dose-response effects of low-intensity exercise on cardiovascular outcomes. Significant interactions were found between walking and total serum cholesterol and skin-fold sums. This study demonstrated the clinical efficacy of a low-intensity exercise regimen on cardiovascular risk factors and exercise adherence.

An ins(X;11)(q24;q23) fuses the MLL and the Septin 6/KIAA0128 gene in an infant with AML-M2

The MLL (HRX, ALL-1 HTRX) gene at chromosome band 11q23 frequently is rearranged in acute lymphoblastic and myeloblastic leukemia. To date, more than 40 different 11q23 abnormalities have been described on the cytogenetic level, and at least 25 of the respective fusion partner genes are cloned. The vast majority of the respective reciprocal translocations generate a chimeric 5'-MLL/partner-3' gene on the derivative 11q23. In this work, we report a unique ins(X;11)(q24;q23) in an infant with acute myeloid leukemia (AML-M2) that fuses the human KIAA0128 gene at Xq24 with MLL. In contrast to the typical reciprocal MLL translocations, however, we provide evidence that the 5'-MLL/KIAA0128-3' fusion resides on Xq24 rather than on 11q23. The KIAA0128 gene encodes the human Septin 6 protein, which contains an ATP-GTP binding motif and three nuclear targeting sequences in its carboxy terminus. The maintenance of the reading frame of the 5'-MLL/KIAA0128-3' mRNA fusion allows for the formation of a novel chimeric protein. Septin 6 is the third member of the Septins that is fused to the MLL protein; the other two are hCDCrel at 22q11 and MSF at 17q25.

Resting esophageal sphincter pressures and deglutition frequency in awake subjects after oropharyngeal topical anesthesia and laryngeal mask device insertion

We investigated the effects of oropharyngeal topical anesthesia and placement of the standard (LMA) and the ProSeal (PLMA) laryngeal mask airway on resting gastroesophageal barrier pressure (GEBP), upper esophageal sphincter pressure (UESP), and deglutition frequency in awake subjects. Each subject was studied on 2 consecutive days: 1 day with the LMA and the other with the PLMA, in random order. GEBP and UESP were measured between deglutitions by using a pull-through technique in five sequential conditions: 1) after acclimatization to the manometer, 2) after topical anesthesia, 3) after the LMA or PLMA was self-inserted and the cuff inflated with either 10 or 30 mL of air in random order, 4) after the cuff volume was adjusted to the other randomized volume, and 5) after LMA or PLMA removal. Deglutition frequency was determined between pressure measurements by using a neck microphone. UESP was always larger than GEBP (P < 0.001 for all). Topical anesthesia had no influence on GEBP, UESP, or deglutition frequency. LMA and PLMA placement did not influence GEBP or UESP, but deglutition frequency was higher (P < 0.02 for all). GEBP and UESP did not vary between devices for any condition. Cuff volume did not influence GEBP or UESP. Deglutition frequency was more frequent for the LMA than the PLMA at a 30-mL cuff volume (P = 0.008). We conclude that resting GEBP and UESP are unaffected by oropharyngeal topical anesthesia and the LMA or PLMA in awake subjects, but that deglutition frequency is increased by the LMA or PLMA. This may have implications for the incidence of regurgitation in these situations.

IMPLICATIONS

Resting gastroesophageal barrier pressure and upper esophageal sphincter pressure are unaffected by oropharyngeal topical anesthesia and laryngeal mask devices in awake subjects, but deglutition frequency is increased by laryngeal mask devices. This may have implications for the incidence of regurgitation in these situations.

Vaginal pessary-induced mechanical bowel obstruction

We present a case of a mechanical bowel obstruction secondary to an impacted vaginal pessary. As the elderly segment of the population continues to grow, pessary use is increasing in absolute numbers, and clinicians must consider these medical devices when evaluating abdominal, gynecological, and urological complaints in elderly women.

Airway protection with the ProSeal laryngeal mask airway

The ProSeal laryngeal mask airway is a new laryngeal mask device that has a modified cuff and a drainage tube. We describe a case where the ProSeal laryngeal mask successfully channelled regurgitated fluid away from the respiratory tract.

Chromatin assembly during S phase: contributions from histone deposition, DNA replication and the cell division cycle

During S phase of the eukaryotic cell division cycle, newly replicated DNA is rapidly assembled into chromatin. Newly synthesised histones form complexes with chromatin assembly factors, mediating their deposition onto nascent DNA and their assembly into nucleosomes. Chromatin assembly factor 1, CAF-1, is a specialised assembly factor that targets these histones to replicating DNA by association with the replication fork associated protein, proliferating cell nuclear antigen, PCNA. Nucleosomes are further organised into ordered arrays along the DNA by the activity of ATP-dependent chromatin assembly and spacing factors such as ATP-utilising chromatin assembly and remodelling factor ACE An additional level of controlling chromatin assembly pathways has become apparent by the observation of functional requirements for cyclin-dependent protein kinases, casein kinase II and protein phosphatases. In this review, we will discuss replication-associated histone deposition and nucleosome assembly pathways, and we will focus in particular on how nucleosome assembly is linked to DNA replication and how it may be regulated by the cell cycle control machinery.

Concurrent primaries of vaginal clear cell adenocarcinoma and endometrial adenocarcinoma in a 39-year old woman with in utero diethylstilbestrol exposure

Diethylstilbestrol (DES) was used widely in the late 1940s in an attempt to prevent adverse pregnancy outcomes. In 1971 the US Food and Drug Administration proscribed its use for pregnancy support secondary to its association with clear cell adenocarcinoma of the vagina. Several studies in animal models demonstrated an association with endometrial cancer among offspring following in utero DES exposure. To date, there is only one case report of endometrial cancer in women exposed to DES in utero. We present the first case, to our knowledge, of a woman exposed to DES in utero who presented with double primaries of clear cell cancer of the vagina concomitant with endometrial cancer.

A comparison of four methods for assessing oropharyngeal leak pressure with the laryngeal mask airway (LMA) in paediatric patients

BACKGROUND

This study compares four tests for assessing oropharyngeal leak pressure with the laryngeal mask airway (LMA). We tested the hypothesis that the oropharyngeal leak pressure and interobserver reliability differs between tests.

METHODS

Eighty paralysed anaesthetized paediatric patients (weight 10-30 kg) were studied with the intracuff pressure set at 60 cmH2O. Four different oropharyngeal leak pressure tests were performed in random order on each patient by two observers blinded to each other's measurements. Test 1 involved detection of an audible noise. Test 2 involved detection of endtidal CO2 in the oral cavity. Test 3 involved observation of the aneroid manometer dial as the pressure increased and noting the airway pressure at which the dial reaches stability. Test 4 involved detection of an audible noise by neck stethoscopy.

RESULTS

The mean oropharyngeal leak pressure was 12.5 cmH2O and was similar between tests. The intraclass correlation coefficient was 0.99 for all tests and was classed as excellent.

CONCLUSIONS

We conclude that all four tests provide accurate and reliable information about oropharyngeal leak pressure in children.

Matrix-dependent mechanism of neutrophil-mediated release and activation of matrix metalloproteinase 9 in myocardial ischemia/reperfusion

BACKGROUND

A key component of reperfusion of myocardial infarction is an immediate inflammatory response, which enhances tissue repair. Matrix turnover is crucial to tissue repair, and matrix metalloproteinases (MMPs) are key enzymes involved in matrix degradation. The hypothesis tested is that one inflammation-based effector of tissue repair is the secretion and activation of MMP-9 by infiltrating neutrophils.

METHODS AND RESULTS

Cardiac lymph and tissue were assayed for atent and active MMP-2 and MMP-9 by zymography and immunochemistry. Dual-labeling immunofluorescence determined the cellular source of MMP-9 protein. Isolated canine neutrophils were incubated with preischemic and postischemic cardiac lymph in the presence and absence of collagen-fibronectin pads, and the supernatants were assayed for latent and active MMP-9. MMP-9 increased during the first hours of reperfusion in both lymph supernatants and myocardial extracts, and this increase was of neutrophil origin. MMP-9 in the cardiac lymph remained latent but was activatable. In contrast, MMP-9 in the myocardium was in both latent and active forms. In situ zymography demonstrated that activated MMP-9 surrounded the infiltrated neutrophils. When postischemic cardiac lymph was incubated with neutrophils in vitro, MMP-9 secretion and activation occurred only in the presence of a collagen-fibronectin substrate; preischemic cardiac lymph did not induce significant secretion or activation.

CONCLUSIONS

Infiltrating neutrophils are an early source of MMP-9 after reperfusion, and a portion of MMP-9 in the myocardium is active. Infiltrating neutrophils may localize MMP-9 activation by secreting MMP-9 and as a source of activating proteases.

Impaired release of ATP from red blood cells of humans with primary pulmonary hypertension

Previously, we reported that in the isolated perfused rabbit lung, red blood cells (RBCs) obtained from either rabbits or healthy humans were a required component of the perfusate to unmask evidence of nitric oxide (NO) participation in regulation of the pulmonary circulation. In addition, we found that mechanical deformation of rabbit and healthy human RBCs released ATP, a known agonist for enhanced NO synthesis. In contrast, RBCs obtained from patients with cystic fibrosis (CF) did not release ATP in response to mechanical deformation. The coexistence of airway disease and alveolar hypoxia in patients with CF precluded the drawing of conclusions relating a defect in RBC ATP release with the pulmonary hypertension associated with CF. Airway disease and alveolar hypoxia are not, however, features of primary pulmonary hypertension (PPH), a human condition of unknown etiology. We postulated that a defect in NO generation might contribute to the increased pulmonary vascular resistance in PPH, and as a first step, we hypothesized that RBCs obtained from patients with PPH would not release ATP. In contrast to RBCs of healthy humans, when RBCs of PPH patients were passed through filters (average pore size 12, 8, or 5 microm), ATP was not released and the RBCs exhibited reduced deformability. Moreover, when incubated with the active cAMP analogue, Sp-cAMP (100 microM), an activator of the CF transmembrane conductance regulator, ATP was not released. These results demonstrate that RBCs obtained from patients with PPH fail to release ATP whether the stimulus is mechanical or pharmacological. Thus, failure of RBCs to release ATP in patients with PPH might be a major pathogenetic factor that accounts for the heretofore unknown etiology of their pulmonary hypertension.

Effect of Teachers' Stereotyping on Students' Stereotyping of Mathematics as a Male Domain

This multilevel analysis used data from a representative sample from Grades 6, 7, and 8 in public schools in Switzerland. The data included information on (a) 6,602 students (3,307 girls, 3,295 boys) nested within 338 classes and (b) 321 mathematics teachers of these classes. The teachers and the students tended to stereotype mathematics as a male domain, and the teachers' stereotypes significantly affected the students' stereotypes after the author controlled for achievement, interest, and self-confidence in mathematics and for school grade and schooling track.

Reversing sevoflurane-associated Q-Tc prolongation by changing to propofol

Congenital or acquired forms of the long Q-T syndrome may result in ventricular tachycardia known as torsade de pointes. Many drugs including volatile anaesthetics modify the Q-T interval. Sevoflurane is known to prolong of the rate-corrected Q-T interval (Q-Tc). The objective of this study was to determine whether the sevoflurane-associated Q-Tc prolongation is rapidly reversible when propofol is substituted for sevoflurane. Thirty-two female patients were allocated to two groups. All patients received sevoflurane induction and anaesthesia for 15 min. In one group, sevoflurane was then discontinued and anaesthesia maintained on propofol for another 15 min. The second group received sevoflurane anaesthesia for 30 min. Measurements were taken before, and 15, 20, 25 and 30 min after induction. Q-Tc prolongation was significantly reduced 5, 10 and 15 min after propofol had been substituted for sevoflurane. We conclude that the sevoflurane-associated Q-Tc prolongation is fully reversible within 15 min when propofol is substituted for sevoflurane.

Reversing sevoflurane-associated Q-Tc prolongation by changing to propofol

Congenital or acquired forms of the long Q-T syndrome may result in ventricular tachycardia known as torsade de pointes. Many drugs including volatile anaesthetics modify the Q-T interval. Sevoflurane is known to prolong of the rate-corrected Q-T interval (Q-Tc). The objective of this study was to determine whether the sevoflurane-associated Q-Tc prolongation is rapidly reversible when propofol is substituted for sevoflurane. Thirty-two female patients were allocated to two groups. All patients received sevoflurane induction and anaesthesia for 15 min. In one group, sevoflurane was then discontinued and anaesthesia maintained on propofol for another 15 min. The second group received sevoflurane anaesthesia for 30 min. Measurements were taken before, and 15, 20, 25 and 30 min after induction. Q-Tc prolongation was significantly reduced 5, 10 and 15 min after propofol had been substituted for sevoflurane. We conclude that the sevoflurane-associated Q-Tc prolongation is fully reversible within 15 min when propofol is substituted for sevoflurane.

[Spontaneous versus controlled respiration with the laryngeal mask. A review]

Over the last 10 years, the Laryngeal Mask Airway (LMA) has gained widespread acceptance as a general purpose airway for routine anaesthesia. Published data from large studies and reports have confirmed the safety and efficacy of the device for spontaneous and controlled ventilation during routine use. The initial experience with the LMA should ideally be confined to short cases requiring the patient to remain spontaneously ventilating. With experience, it will be found that less anesthetic agent is required during anesthesia with the LMA and patient recovery should be improved as a result. Spontaneous breathing is the chosen mode of ventilation in approximately 60% of LMA uses in the UK. During spontaneous breathing a minimal inspiratory pressure support will help with higher endtidal carbon dioxide levels. The anaesthetist should be experienced with using the LMA in spontaneously ventilating patients before using it with positive pressure ventilation. Several large scale studies have failed to show any link between positive pressure ventilation and pulmonary aspiration or gastric insufflation. The main disadvantage of the LMA is that it does not protect against aspiration. From a practical point of view, most fasted patients with normal lung compliance may be mechanically ventilated through the LMA to airway pressures of approximately 20 cmH2O. The low pressure seal implies that tidal volumes should be approximately 6-8 ml*kg-1 and the inspiratory flow rates should be reduced to achieve adequate and safe ventilation.

Protective effect of halothane anesthesia on retinal light damage: inhibition of metabolic rhodopsin regeneration

PURPOSE

To determine whether the volatile anesthetic halothane protects against light-induced photoreceptor degeneration in the rodent retina.

METHODS

Albino mice and rats were anesthetized with halothane and exposed to high levels of white or blue light. Nonanesthetized animals served as controls. Retinal morphology was assessed by light microscopy, and apoptosis of photoreceptor cells was verified by detection of fragmented genomic DNA and in situ staining of apoptotic nuclei (TUNEL assay). Rhodopsin regeneration after bleaching was determined by measuring rhodopsin levels in retinas of mice or rats at different time points in darkness.

RESULTS

Halothane anesthesia reversibly inhibited metabolic rhodopsin regeneration and thus prevented rhodopsin from absorbing high numbers of photons during light exposure. Consequently, photoreceptors of mice and rats anesthetized with halothane were completely protected against degeneration induced by white light. In remarkable contrast, however, halothane anesthesia did not protect against blue-light-induced photoreceptor cell death.

CONCLUSIONS

After the initial bleach, halothane impeded photon absorption by rhodopsin by inhibiting metabolic rhodopsin regeneration. Apparently, the rhodopsin-mediated uptake of the critical number of photons to initiate white light-induced retinal degeneration was prevented. In contrast, halothane did not protect the retina against blue light. Blue light can efficiently restore functional rhodopsin from bleaching intermediates through a process termed photoreversal of bleaching. This process does not depend on the visual cycle via the pigment epithelium but nevertheless enables rhodopsin molecules to absorb the critical number of photons required to induce retinal degeneration.

Nucleotide and deduced amino acid sequence of equine retinal and pineal gland phosducin

OBJECTIVES

To determine the full-length complementary DNA (cDNA) sequence of equine retinal and pineal gland phosducin (PHD) and to clone these sequences.

SAMPLE POPULATION

Samples of equine retinal RNA.

PROCEDURE

A primer set was designed for use in identifying a fragment of the equine PHD nucleotide sequence, derived from retinal RNA samples, and subsequently for use to deduce specific primers for additional examination. The full-length cDNA was determined by the method of rapid amplification of cDNA ends (RACE). For full-length cDNA, newly designed primers were used. Nucleotide sequences were analyzed by use of computer software. The deduced amino acid sequence was compared with sequences of PHD reported for other species. In addition, the sequence of equine pineal PHD was cloned.

RESULTS

The cDNA nucleotide sequence for equine PHD was 1,209 base pairs (bp) in length with an open-reading frame encoding a protein of 245 amino acids and a calculated molecular mass of 28.214 kd. Similarity with amino acid sequences of PHD from other species was 89 to 93%. Sequences of equine PHD from retina and pineal gland were identical. Equine PHD contained a peptide sequence with 100% homology to an uveitopathogenic peptide reported for rat PHD.

CONCLUSIONS

Equine PHD is a highly conserved protein that has homology of immunologic interest with rat PHD. These results establish a basis for studying the role of PHD in ocular inflammation of horses.

Mutations in the low-density-lipoprotein receptor gene in German patients with familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is an autosomal dominant disorder of lipid metabolism characterized by elevated low-density lipoproteins (LDL), the formation of tendon and skin xanthomata and the development of premature coronary atherosclerosis. It is caused by a defect in the receptor-mediated hepatic uptake of LDL due to mutations in the LDL receptor. In 25 FH families with a total of 160 members and in two individuals without available relatives, all of German origin, we identified LDL receptor mutations by a multiplex-PCR-based single-strand conformation polymorphism method followed by direct sequencing. Of the 24 mutations found, 15 are missense mutations, 2 are nonsense mutations, 4 are small deletions or insertions leading to frameshifts, 2 are an in-frame insertion and deletion, respectively, and one is a splice site mutation. Propositi carrying mutations that are known to completely abolish receptor function (nonsense and frameshift mutations, missense mutation V480M) had significantly higher untreated total and LDL-cholesterol levels compared to those patients carrying missense and in-frame insertion mutations of unknown functional consequence, which may lead to either reduced or completely abolished receptor function (11.30+/-1.64 vs 9.76+/-1.50 mmol/L, and 9.39+/-1.23 vs 7.99+/-1.45 mmol/L, respectively). These results confirm the clinical and molecular heterogeneity of FH and the influence of different functional classes of mutations on lipid values.

Block of wild-type and inactivation-deficient cardiac sodium channels IFM/QQQ stably expressed in mammalian cells

The role of inactivation as a central mechanism in blockade of the cardiac Na(+) channel by antiarrhythmic drugs remains uncertain. We have used whole-cell and single channel recordings to examine the block of wild-type and inactivation-deficient mutant cardiac Na(+) channels, IFM/QQQ, stably expressed in HEK-293 cells. We studied the open-channel blockers disopyramide and flecainide, and the lidocaine derivative RAD-243. All three drugs blocked the wild-type Na(+) channel in a use-dependent manner. There was no use-dependent block of IFM/QQQ mutant channels with trains of 20 40-ms pulses at 150-ms interpulse intervals during disopyramide exposure. Flecainide and RAD-243 retained their use-dependent blocking action and accelerated macroscopic current relaxation. All three drugs reduced the mean open time of single channels and increased the probability of their failure to open. From the abbreviation of the mean open times, we estimated association rates of approximately 10(6)/M/s for the three drugs. Reducing the burst duration contributed to the acceleration of macroscopic current relaxation during exposure to flecainide and RAD-243. The qualitative differences in use-dependent block appear to be the result of differences in drug dissociation rate. The inactivation gate may play a trapping role during exposure to some sodium channel blocking drugs.

Requirement of Cyclin/Cdk2 and protein phosphatase 1 activity for chromatin assembly factor 1-dependent chromatin assembly during DNA synthesis

The influence of reversible protein phosphorylation on nucleosome assembly during DNA replication was analyzed in extracts from human cells. Inhibitor studies and add-back experiments indicated requirements of cyclin A/Cdk2, cyclin E/Cdk2, and protein phosphatase type 1 (PP1) activities for nucleosome assembly during DNA synthesis by chromatin assembly factor 1 (CAF-1). The p60 subunit of CAF-1 is a molecular target for reversible phosphorylation by cyclin/Cdk complexes and PP1 during nucleosome assembly and DNA synthesis in vitro. Purified p60 can be directly phosphorylated by purified cyclin A/Cdk2, cyclin E/Cdk2, and cyclin B1/Cdk1, but not by cyclin D/Cdk4 complexes in vitro. Cyclin B1/Cdk1 triggers hyperphosphorylation of p60 in the presence of additional cytosolic factors. CAF-1 containing hyperphosphorylated p60 prepared from mitotic cells is inactive in nucleosome assembly and becomes activated by dephosphorylation in vitro. These data provide functional evidence for a requirement of the cell cycle machinery for nucleosome assembly by CAF-1 during DNA replication.

Social and contextual etiology of coronary heart disease in women

We explored the social and contextual etiology of coronary heart disease (CHD) prevention and management in women. Social and contextual influences on CHD risk include such factors as socioeconomic status, access to healthcare, cultural mores, working conditions including work overload, multiple role responsibilities, and social isolation. Women, particularly economically disadvantaged women, occupy lower levels on the social status hierarchy and, therefore, experience more stressful life experiences, less favorable living conditions, and less opportunity to affect positive health behavior and outcomes. Women are often discriminated against economically, politically, and socially, and this discrimination may adversely affect their efforts at CHD health promotion and treatment. Multiple role responsibilities within the family and psychosocial factors, including chronic life stress, are critical to an understanding of the health status of women, particularly poor and minority women. Although community-based interventions appear to be ideal for addressing the contextual risks related to CHD in women, a number of issues need to be considered, for example, the limited acknowledgment of secular trends in economic development that influence lifestyle decisions and health promotion efforts. Directions for research and interventions include recognition of the full spectrum of CHD risk in women, recognition of culturally competent interventions, and recognition of the need for empowerment of women.

A fibreoptic scoring system to assess the position of laryngeal mask airway devices. Interobserver variability and a comparison between the standard, flexible and intubating laryngeal mask airways

We determined the interobserver reliability of a fibreoptic scoring system for assessing the position of the laryngeal mask airway (LMA), the flexible laryngeal mask airway (FLMA) and the intubating laryngeal mask airway (ILM). We also compare fibreoptic position between the devices. Thirty anaesthetised adult patients were studied in random order in a triple crossover manner. Two observers blinded to each others findings scored the fibreoptic position as follows: 4, only vocal cords visible; 3, vocal cords plus posterior epiglottis visible; 2, vocal cords plus anterior epiglottis visible; 1, vocal cords not seen. Interobserver reliability was examined using intraclass correlation coefficient (ICC). Interobserver reliability was graded as excellent for the LMA (ICC = 0.89), FLMA (ICC = 0.87) and ILM (ICC = 0.79). Fibreoptic scores were higher for the LMA and FLMA compared with the ILM (both p < 0.001). We conclude that interobserver reliability for the fibreoptic scoring system is excellent for the LMA, FLMA and ILM. Fibreoptic position is better for the LMA and FLMA compared with the ILM. Fibreoptic scoring has potential utility for research and clinical practice with laryngeal mask devices.

Cervical spine motion during airway management: a cinefluoroscopic study of the posteriorly destabilized third cervical vertebrae in human cadavers

We conducted a randomized, controlled, crossover study to determine cervical spine motion for six airway management techniques in human cadavers with a posteriorly destabilized third cervical (C-3) vertebra. A destabilized C-3 segment was created in 10 cadavers (6-24 h postmortem). Cervical motion was recorded by continuous lateral fluoroscopy. The following airway management techniques were performed in random order on each cadaver with manual in-line stabilization applied: face mask ventilation (FM), laryngoscope-guided orotracheal intubation (OETT), fiberscope-guided nasal intubation (FOS-NETT), esophageal tracheal Combitube((R)) (Kendall-Sheridan, Neustadt, Germany) insertion (ETC), intubating laryngeal mask insertion with fiberscope-guided tracheal intubation (ILM-OETT), and laryngeal mask airway insertion (LMA). Afterward, maximum head-neck flexion (FLEX-MAX) and maximum head-neck extension (EXT-MAX) without manual in-line stabilization was performed to determine maximum motion. The maximum posterior displacement of C-3 and the maximum segmental sagittal motion of C2-3 were determined. There was a significant increase in posterior displacement for the FM (1.9 +/- 1.2 mm, P: < 0.01), OETT (2.6 +/- 1.6 mm, P: < 0.0001), ETC (3.2 +/- 1.6 mm, P: < 0.0001), ILM-OETT (1.7 +/- 1.3 mm, P: < 0. 01), LMA (1.7 +/- 1.3 mm, P: < 0.01), FLEX-MAX (3.7 +/- 1.9 mm, P: < 0.0001), EXT-MAX (1.8 +/- 1.7, P: < 0.01), however, not for FOS-NETT (0.1 +/- 0.7 mm). Posterior displacement was less for the ILM-OETT and LMA than for the ETC (both P: < 0.04). There were no significant increases in segmental sagittal motion with any airway manipulation other than with FLEX-MAX (-4.5 +/- 4.0 degrees, P: < 0.01). Posterior displacement was similar to FLEX-MAX for the OETT and ETC; however, it was less for the FM, FOS-NETT, ILM-OETT, and LMA (all P: < 0.01). Posterior displacement was similar to EXT-MAX for all airway manipulations other than for FOS-NETT (P: < 0.001). For cervical motion and the techniques tested, the safest method of airway management in a patient with a posteriorly destabilized C-3 segment is FOS-NETT. LMA devices may be preferable to the ETC.

IMPLICATIONS

In the cadaver model of a destabilized third cervical vertebrae, significant displacement of the injured segment occurs during airway management with the face mask, laryngoscope-guided oral intubation, the esophageal tracheal Combitube (Kendall-Sheridan, Neustadt, Germany), the intubating and standard laryngeal mask airway; but not with fiberscope-guided nasal intubation. For cervical motion and the techniques tested, the safest airway technique with this injury is fiberscope-guided nasotracheal intubation. Laryngeal mask devices are preferable to the esophageal tracheal Combitube.

Does efficacy of seal and fibreoptic view change during anaesthesia with the laryngeal mask airway: a comparison of oxygen and oxygen-nitrous oxide gas mixtures

BACKGROUND

We test the hypothesis that oropharyngeal leak pressure (OLP) and fibreoptic position (FP) are stable for the laryngeal mask airway (LMA) during anaesthesia with and without nitrous oxide.

METHODS

Forty paralysed anaesthetised patients (ASA 1-2, aged 18-80) were randomly allocated to receive 100% oxygen (O2 group) or 33% oxygen in nitrous oxide (O2-N2O group) for maintenance. In vivo intracuff pressure (CP) using a size 5 LMA was adjusted to 60 cm H2O. OLP, FP and CP were measured every 5 min for 30 min.

RESULTS

CP was higher in the O2-N2O group than the O2 group, other than at time zero (all: P<0.0001). CP increased every 5 min in the O2-N2O group (all: P<0.0001), but not in the O2 group. There were no differences in OLP and FP between groups at any time. There were no significant changes in OLP or FP with time within each group. There were no changes in OLP greater than 1.5 cm H2O and no change in FP for any patient.

CONCLUSION

We conclude that OLP and FP are stable for the LMA during anaesthesia lasting 30 min with or without nitrous oxide.

Does the ProSeal laryngeal mask airway prevent aspiration of regurgitated fluid?

In this randomized, cross-over cadaver study, we determined whether a new airway device, the ProSeal laryngeal mask airway (PLMA; Laryngeal Mask Company, Henley-on-Thames, UK), prevents aspiration of regurgitated fluid. We studied five male and five female cadavers (6-24 h postmortem). The infusion set of a pressure-controlled, continuous flow pump was inserted into the upper esophagus and ligated into place. Esophageal pressure (EP) was increased in 2-cm H(2)O increments. This was performed without an airway device (control) and over a range of cuff volumes (0-40 mL) for the classic laryngeal mask airway (LMA), the PLMA with the drainage tube clamped (PLMA clamped) and unclamped (PLMA unclamped). The EP at which fluid was first seen with a fiberoptic scope in the hypopharynx (control), above or below the cuff, or in the drainage tube, was noted. Mean EP at which fluid was seen without any airway device was 9 (range 8-10) cm H(2)O. EP at which fluid was seen was always higher for the PLMA clamped and LMA compared with the control (all, P<0.0001). The mean EP at which fluid was seen for the PLMA unclamped was similar to the control at 10 (range 8-13) cm H(2)O. For the PLMA unclamped, fluid appeared from the drainage tube in all cadavers at 10-40 mL cuff volume and in 8 of 10 cadavers at zero cuff volume. Mean EP at which fluid was seen above the cuff was similar for the PLMA clamped and LMA at 0-30 mL cuff volume, but was higher for PLMA clamped at 40-mL cuff volume (81 vs 48 cm H(2)O, P = 0.006). Mean EP at which fluid was seen below the cuff was similar at 0-10 mL cuff volume, but was higher for the PLMA clamped at 20, 30, and 40 mL cuff volume (62, 68, 73 vs. 46, 46, 46 cm H(2)O, respectively, P<0.04). For the PLMA clamped and the LMA, fluid appeared simultaneously above and below the cuff at all cuff volumes. We concluded that in the cadaver model, the correctly placed PLMA allows fluid in the esophagus to bypass the pharynx and mouth when the drainage tube is open. Both the LMA, and PLMA with a closed drainage tube, attenuate liquid flow between the esophagus and pharynx. This may have implications for airway protection in unconscious patients.

Effect of low-dose citrate anticoagulation on the clinical safety and efficacy of direct adsorption of lipoproteins (DALI apheresis) in hypercholesterolemic patients: a prospective controlled clinical trial

Direct adsorption of lipoproteins (DALI) is the first lipid apheresis system compatible with whole blood with the advantage of a very simple procedure. A mixture of heparin plus citrate (ACD-A) is used for the anticoagulation regimen (AR). A clinical, prospective, controlled crossover study was performed to test the safety and efficacy of low-dose citrate (LDC) anticoagulation in DALI. Five chronic DALI patients suffering from coronary heart disease and hypercholesterolemia underwent 3 DALI sessions each using the LDC anticoagulation regimen (60 IU heparin/kg body weight as initial bolus; 1:40 ACD-A: blood as perfusion). This was compared to 3 sessions per patient with the standard AR (bolus of 20 IU heparin/kg, 1:20 ACD-A as perfusion). Patient blood volumes (1.6; average of 7,040 ml) were treated with 750 ml adsorber gel per session at a blood flow rate of 60 ml/min. Mean LDL and Lp(a) reductions exceeded 60% with both AR. No clinical side effects were observed. Both AR controlled the coagulation well as evidenced by a sufficient prolongation of the partial prothrombin time (PTT) and activated clotting time as well as low thrombin-antithrombin (TAT) formation. Biocompatibility parameters exhibited favorable results (low activation of complement and cells, and only slight formation of C3a, C5a, beta-thromboglobulin, elastase, and TNF-alpha). The asymptomatic bradykinin generation was comparable in both study arms. LDC optimized the ionized calcium levels and pH in the efferent blood postadsorber. LDC anticoagulation was safe and effective, and may further improve the tolerance of DALI apheresis in hypercholesterolemic patients.

A pilot study of left tracheal pulse oximetry

We tested the hypothesis that left tracheal pulse oximetry (SpO(2)) is more accurate than finger SpO(2) when compared with oxygen saturation from arterial blood samples (SaO(2)) in anesthetized patients with normal thoracic anatomy. We also tested the hypothesis that tracheal oximetry readings are primarily derived from the tracheal mucosa. We studied 20 hemodynamically stable, well oxygenated, anesthetized patients with normal anatomy (ASA physical status I-III, 18-80 yr old). A single-use pediatric pulse oximeter was attached to the left lateral surface of a tracheal tube cuff. Tracheal and finger SpO(2) (dominant index finger), and SaO(2) (nondominant radial artery) were taken with the intracuff pressure at 0-60 cm H(2)O. Tracheal SpO(2) was the same as SaO(2) at an intracuff pressure of 10-60 cm H(2)O, but was less when the intracuff pressure was zero (P<0.0001). Tracheal SpO(2) was higher than finger SpO(2) at an intracuff pressure of 10-60 cm H(2)O (all: P <0.001), but was lower when the intracuff pressure was zero (P< 0.0001). SaO(2) was always higher than finger SaO(2) (P<0.0001). Tracheal SpO(2) was lower at an intracuff pressure of zero (P< 0.0001), but was otherwise similar over the range of intracuff pressures. SaO(2) and finger SpO(2) did not vary with intracuff pressure. Tracheal SpO(2) agrees more closely with SaO(2) than finger SpO(2) at an intracuff pressure of 10-60 cm H(2)O (mean difference < 0.2%). We conclude that left tracheal SpO(2) is feasible and provides similar readings to arterial blood samples and more accurate readings than finger oximetry in hemodynamically stable, well oxygenated, anesthetized patients with normal thoracic anatomy. Tracheal oximetry readings are not primarily derived from the tracheal mucosa. The technique merits further evaluation.

Successful pharyngeal pulse oximetry in low perfusion states

PURPOSE

We describe pharyngeal oximetry with the laryngeal mask airway in two patients with low perfusion states where finger oximetry failed.

CLINICAL FEATURES

One patient was a 47-yr-old man with septic shock and the other a 64-yr-old man with multiorgan failure. In both patients, a # 4 laryngeal mask airway with a pediatric pulse oximeter probe was inserted behind the tracheal tube. A good waveform was obtained and oxygen saturation was 0-2% lower than arterial samples.

CONCLUSION

Pharyngeal oximetry with the laryngeal mask airway is feasible in low perfusion states when finger oximetry fails.

Continuous positive airway pressure at 10 cm H(2)O during cardiopulmonary bypass improves postoperative gas exchange

Postbypass pulmonary dysfunction including atelectasis and increased shunting is a common problem in the intensive care unit. Negative net fluid balance and continuous positive airway pressure (CPAP) have been used to reduce the adverse effects of cardiopulmonary bypass (CPB) on the lung. To determine whether CPAP at 10 cm H(2)O during CPB results in improved postoperative gas exchange in comparison with deflated lungs during CPB, we examined 14 patients scheduled for elective cardiac surgery. Seven patients received CPAP at 10 cm H(2)O during CPB, and in the other seven patients, the lungs were open to the atmosphere (control). Measurements were taken before and after CPB, after thoracic closure, and 4 h after CPB in the intensive care unit. CPAP at 10 cm H(2)O resulted in significantly more perfusion of lung areas with a normal ventilation/perfusion distribution (V(A)/Q) and significantly less shunt and low V(A)/Q perfusion 4 h after CPB in comparison with the control group. Consequently, arterial oxygen partial pressure was significantly higher and alveolar-arterial oxygen partial pressure difference was significantly smaller. We conclude that CPAP at 10 cm H(2)O during CPB is a simple maneuver that improves postoperative gas exchange.

IMPLICATIONS

Inflation of the lungs at a pressure of 10 cm H(2)O as compared with leaving the lungs deflated during cardiopulmonary bypass was examined. Lung inflation during bypass resulted in significantly improved postoperative gas exchange.