Inspiratory and end-expiratory effects of lung recruitment in the prone position on dorsal lung aeration - new physiological insights in a secondary analysis of a randomised controlled study in post-cardiac surgery patients

Background

Cardiac surgery produces dorso-basal atelectasis and ventilation/perfusion mismatch, associated with infection and prolonged intensive care. A postoperative lung volume recruitment manoeuvre to decrease the degree of atelectasis is routine. In patients with severe respiratory failure, prone positioning and recruitment manoeuvres may increase survival, oxygenation, or both. We compared the effects of lung recruitment in prone vs supine positions on dorsal inspiratory and end-expiratory lung aeration.

Methods

In a prospective RCT, 30 post-cardiac surgery patients were randomly allocated to recruitment manoeuvres in the prone (n=15) or supine position (n=15). The primary endpoints were late dorsal inspiratory volume (arbitrary units [a.u.]) and left/right dorsal end-expiratory lung volume change (a.u.), prone vs supine after extubation, measured using electrical impedance tomography. Secondary outcomes included left/right dorsal inspiratory volumes (a.u.) and left/right dorsal end-expiratory lung volume change (a.u.) after prone recruitment and extubation.

Results

The last part of dorsal end-inspiratory volume after extubation was higher after prone (49.1 a.u.; 95% confidence interval [CI], 37.4-60.6) vs supine recruitment (24.2 a.u.; 95% CI, 18.4-29.6; P=0.024). Improvement in left dorsal end-expiratory lung volume after extubation was higher after prone (382 a.u.; 95% CI, 261-502) vs supine recruitment (-71 a.u., 95% CI, -140 to -2; n=15; P<0.001). After prone recruitment, left vs right predominant end-expiratory dorsal lung volume change disappeared after extubation. However, both left and right end-expiratory volumes were higher in the prone group, after extubation.

Conclusions

Recruitment in the prone position improves dorsal inspiratory and end-expiratory lung volumes after cardiac surgery.

Clinical trial registration

NCT03009331.

Lung recruitment in the prone position after cardiac surgery: a randomised controlled study

BACKGROUND

Atelectasis after cardiac surgery is common and promotes ventilation/perfusion mismatch, infection, and delayed discharge from critical care. Recruitment manoeuvres are often performed to reduce atelectasis. In severe respiratory failure, recruitment manoeuvres in the prone position may increase oxygenation, survival, or both. We compared the effects of recruitment manoeuvres in the prone vs supine position on lung aeration and oxygenation in cardiac surgical patients.

METHODS

Subjects were randomised to recruitment manoeuvres (40 cm H₂O peak inspiratory pressure and 20 cm H₂O PEEP for 30 s) in either the prone or supine position after uncomplicated cardiac surgery. The co-primary endpoints were lung aeration (end-expiratory lung volume measured by electrical impedance tomography (arbitrary units [a.u.]) and lung oxygenation (ratio of arterial oxygen partial pressure to fractional inspired oxygen [Pao₂/FiO₂ ratio]). Secondary outcomes included postoperative oxygen requirement and adverse events.

RESULTS

Thirty subjects (27% female; age, 48-81 yr) were recruited. Dorsal lung tidal volume was higher after prone recruitment manoeuvres (363 a.u.; 95% confidence intervals [CI], 283-443; n=15) after extubation, compared with supine recruitment manoeuvres (212 a.u.; 95% CI, 170-254; n=15; P<0.001). Prone recruitment manoeuvres increased dorsal end-expiratory lung volume by 724 a.u. (95% CI, 456-992) after extubation, compared with 163 a.u. decrease (95% CI, 73-252) after supine recruitment manoeuvres (P<0.001). The Pao₂/FiO₂ ratio after extubation was higher after prone recruitment manoeuvres (46.6; 95% CI, 40.7-53.0) compared with supine recruitment manoeuvres (39.3; 95% CI, 34.8-43.8; P=0.04). Oxygen therapy after extubation was shorter after prone (33 h [13]) vs supine recruitment manoeuvres (52 h [22]; P=0.01). No adverse events occurred.

CONCLUSIONS

Recruitment manoeuvres in the prone position after cardiac surgery improve lung aeration and oxygenation.

CLINICAL TRIAL REGISTRATION

NCT03009331.

Assessing neurological prognosis in post-cardiac arrest patients from short vs plain text EEG reports: A survey among intensive care clinicians

BACKGROUND

Electroencephalography (EEG) patterns are predictive of neurological prognosis in comatose survivors from cardiac arrest but intensive care clinicians are dependent of neurophysiologist reports to identify specific patterns. We hypothesized that the proportion of correct assessment of neurological prognosis would be higher from short statements confirming specific EEG patterns compared with descriptive plain text reports.

METHODS

Volunteering intensive care clinicians at two university hospitals were asked to assess the neurological prognosis of a fictional patient with high neuron specific enolase. They were presented with 17 authentic plain text reports and three short statements, confirming whether a "highly malignant", "malignant" or "benign" EEG pattern was present. Primary outcome was the proportion of clinicians who correctly identified poor neurological prognosis from reports consistent with highly malignant EEG patterns. Secondary outcomes were how the prognosis was assessed from reports consistent with malignant and benign patterns.

RESULTS

Out of 57 participants, poor prognosis was correctly identified by 61% from plain text reports and by 93% from the short statement "highly malignant" EEG patterns. Unaffected prognosis was correctly identified by 28% from plain text reports and by 40% from the short statement "malignant" patterns. Good prognosis was correctly identified by 64% from plain text reports and by 93% from the short statement "benign" pattern.

CONCLUSION

Standardized short statement, "highly malignant EEG pattern present", as compared to plain text EEG descriptions in neurophysiologist reports, is associated with more accurate identification of poor neurological prognosis in comatose survivors of cardiac arrest.

Dry Rehydratable Film Method for Enumerating Confirmed Escherichia coli in Poultry, Meats, and Seafood: Collaborative Study

A rehydratable dry-film plating method for Escherichia coli, the Petrifilm E. coli/Coliform (EC) Count Plate in foods, has been compared with the AOAC INTERNATIONAL most probable number (MPN) method. Eleven laboratories participated in the collaborative study. Three E. coli levels in 8 samples each of frozen raw ground turkey, frozen raw ground beef, and frozen cooked fish were tested in duplicate. Mean log counts for the Petri film plate procedure were not significantly different from those for the MPN procedure for cooked fish samples inoculated with low or high inocula levels, for samples of raw turkey inoculated at medium level, and for beef inoculated at low, medium, and high levels. Repeatability and reproducibility vari ances of the Petrifilm EC Plate method recorded at 24 h were as good as or better than those of the MPN method. The dry rehydratable film method for enumerating confirmed E. coli in poultry, meats, and seafood has been adopted first action by AOAC INTERNATIONAL.

VIDAS® Enzyme-Linked Immunofluorescent Assay for Detection of Listeria in Foods: Collaborative Study

The VIDAS LIS method and the traditional culture methods for detection of Listeria species in food were evaluated in a multilaboratory comparative study. The 6 foods tested were either naturally contaminated or inoculated with 3 different concentrations of Listeria. Results for each food and each contamination level with the VIDAS LIS method were as good as or better than those obtained with the traditional culture method. Of 1558 samples tested, 935 were positive: 839 by the VIDAS method and 809 by standard culture methods. Overall false negative rates were 10.3 and 13.5% for the VIDAS LIS and culture methods, respectively. The false positive rate for the VIDAS LIS assay was 1.4% based on 9 VIDAS LIS positive assays that did not confirm positive by isolation of Listeria. The agreement between the VIDAS LIS and culture methods for all samples tested was 86%.

Analysis of central venous access injuries from claims to the Swedish Patient Insurance Company 2009-2017

INTRODUCTION

Insertion and use of central venous access devices (CVADs) can be associated with serious adverse events. The incidence is generally low but considering the vast use of CVADs the consequences can, from a patient safety and health economics perspective, be severe. No exact knowledge exists of number of catheters or complications in Sweden, as there is currently no comprehensive registry. The aim was to analyse injuries reported to the Swedish National Patient Insurance Company (Löf) within 7 days after insertion or removal of a CVAD.

METHODS

A retrospective analysis of all injuries filed in the period 2009-2017 was performed, evaluating patient data, type of catheter, insertion technique and type of injury. If the injury was deemed avoidable by Löf, degree of disability and mortality was registered.

RESULTS

A total of 87 claims of injuries were found of which 36 (41%) were assessed as avoidable. The most common injuries were: bleeding (18%), early infection (17%), pneumothorax (17%) and early thrombosis (15%). No patients died of their injuries, but 17 of 36 suffered permanent disability of varying degrees. Ultrasound-guided insertion was used in 19% of the cases.

CONCLUSION

In Sweden, few injuries related to CVAD use are reported to Löf. About 40% of filed claims were categorized as having an avoidable injury and therefore eligible for compensation. About half of the compensated patients suffered a permanent disability. The results indicate underreporting of CVC-related injuries in Sweden during the studied time-period.

Isocapnic hyperventilation provides early extubation after head and neck surgery: A prospective randomized trial

BACKGROUND

Isocapnic hyperventilation (IHV) shortens recovery time after inhalation anaesthesia by increasing ventilation while maintaining a normal airway carbon dioxide (CO2 )-level. One way of performing IHV is to infuse CO2 to the inspiratory limb of a breathing circuit during mechanical hyperventilation (HV). In a prospective randomized study, we compared this IHV technique to a standard emergence procedure (control).

METHODS

Thirty-one adult ASA I-III patients undergoing long-duration (>3 hours) sevoflurane anaesthesia for major head and neck surgery were included and randomized to IHV-treatment (n = 16) or control (n = 15). IHV was performed at minute ventilation 13.6 ± 4.3 L/min and CO2 delivery, dosed according to a nomogram tested in a pilot study. Time to extubation and eye-opening was recorded. Inspired (FICO2 ) and expired (FETCO2 ) CO2 and arterial CO2 levels (PaCO2 ) were monitored. Cognition was tested preoperatively and at 20, 40 and 60 minutes after surgery.

RESULTS

Time from turning off the vapourizer to extubation was 13.7 ± 2.5 minutes in the IHV group and 27.4 ± 6.5 minutes in controls (P < .001). Two minutes after extubation, PaCO2 was 6.2 ± 0.5 and 6.2 ± 0.6 kPa in the IHV and control group respectively. In 69% (IHV) vs 53% (controls), post-operative cognition returned to pre-operative values within 40 minutes after surgery (NS). Incidences of pain and nausea/vomiting did not differ between groups.

CONCLUSIONS

In this randomized trial comparing an IHV method with a standard weaning procedure, time to extubation was reduced with 50% in the IHV group. The described IHV method can be used to decrease emergence time from inhalation anaesthesia.

Evaluation of a method for isocapnic hyperventilation: a clinical pilot trial

BACKGROUND

Isocapnic hyperventilation (IHV) is a method that shortens time to extubation after inhalation anaesthesia using hyperventilation (HV) without lowering airway CO₂ . In a clinical trial on patients undergoing long-duration sevoflurane anaesthesia for major ear-nose-throat (ENT) surgery, we evaluated the utility of a technique for CO₂ delivery (DCO₂ ) to the inspiratory limb of a closed breathing circuit, during HV, to achieve isocapnia.

METHODS

Fifteen adult ASA 1-3 patients were included. After end of surgery, mechanical HV was started by doubling baseline minute ventilation. Simultaneously, CO₂ was delivered and dosed using a nomogram developed in a previous experimental study. Time to extubation and eye opening was recorded. Inspired (FICO₂ ) and expired (FETCO₂ ) CO₂ and arterial CO₂ levels were monitored during IHV. Cognition was tested pre-operatively and at 20, 40 and 60 min after surgery.

RESULTS

A DCO₂ of 285 ± 45 ml/min provided stable isocapnia during HV (13.5 ± 4.1 l/min). The corresponding FICO₂ level was 3.0 ± 0.3%. Time from turning off the vaporizer (1.3 ± 0.1 MACage) to extubation (0.2 ± 0.1 MACage) was 11.3 ± 1.8 min after 342 ± 131 min of anaesthesia. PaCO₂ and FETCO₂ remained at normal levels during and after IHV. In 85% of the patients, post-operative cognition returned to pre-operative values within 60 min.

CONCLUSIONS

In this cohort of patients, a DCO₂ nomogram for IHV was validated. The patients were safely extubated shortly after discontinuing long-term sevoflurane anaesthesia. Perioperatively, there were no adverse effects on arterial blood gases or post-operative cognition. This technique for IHV can potentially be used to decrease emergence time from inhalation anaesthesia.

Target temperature 34 vs. 36°C after out-of-hospital cardiac arrest - a retrospective observational study

BACKGROUND

Intensive care for comatose survivors of cardiac arrest includes targeted temperature management (TTM) to attenuate cerebral reperfusion injury. A recent multi-center clinical trial did not show any difference in mortality or neurological outcome between TTM targeting 33°C or 36°C after out-of-hospital-cardiac-arrest (OHCA). In our institution, the TTM target was changed accordingly from 34 to 36°C. The aim of this retrospective study was to analyze if this change had affected patient outcome.

METHODS

Intensive care registry and medical record data from 79 adult patients treated for OHCA with TTM during 2010 (n = 38; 34°C) and 2014 (n = 41; 36°C) were analyzed for mortality and neurological outcome were assessed as cerebral performance category. Student's t-test was used for continuous data and Fischer's exact test for categorical data, and multivariable logistic regression was applied to detect influence from patient factors differing between the groups.

RESULTS

Witnessed arrest was more common in 2010 (95%) vs. 2014 (76%) (P = 0.03) and coronary angiography was more common in 2014 (95%) vs. 2010 (76%) (P = 0.02). The number of patients awakening later than 72 h after the arrest did not differ. After adjusting for gender, hypertension, and witnessed arrest, neither 1-year mortality (P = 0.77), nor 1-year good neurological outcome (P = 0.85) differed between the groups.

CONCLUSION

Our results, showing no difference between TTM at 34°C and TTM at 36°C as to mortality or neurological outcome after OHCA, are in line with the previous TTM-trial results, supporting the use of either target temperature in our institution.

Isocapnic hyperventilation shortens washout time for sevoflurane - an experimental in vivo study

BACKGROUND

Isocapnic hyperventilation (IHV) is a method that fastens weaning from inhalation anaesthesia by increasing airway concentration of carbon dioxide (CO2 ) during hyperventilation (HV). In an animal model, we evaluated a technique of adding CO2 directly to the breathing circuit of a standard anaesthesia apparatus.

METHODS

Eight anaesthetised pigs weighing 28 ± 2 kg were intubated and mechanically ventilated. From a baseline ventilation of 5 l/min, HV was achieved by doubling minute volume and fresh gas flow. Respiratory rate was increased from 15 to 22/min. The CO2 absorber was disconnected and CO2 was delivered (DCO2 ) to the inspiratory limb of a standard breathing circuit via a mixing box. Time required to decrease end-tidal sevoflurane concentration from 2.7% to 0.2% was defined as washout time. Respiration and haemodynamics were monitored by blood gas analysis, spirometry, electric impedance tomography and pulse contour analysis.

RESULTS

A DCO2 of 261 ± 19 ml/min was necessary to achieve isocapnia during HV. The corresponding FICO2 -level remained stable at 3.1 ± 0.3%. During IHV, washout of sevoflurane was three times faster, 433 ± 135 s vs. 1387 ± 204 s (P < 0.001). Arterial CO2 tension and end-tidal CO2 , was 5.2 ± 0.4 kPa and 5.6 ± 0.4%, respectively, before IHV and 5.1 ± 0.3 kPa and 5.7 ± 0.3%, respectively, during IHV.

CONCLUSIONS

In this experimental in vivo model of isocapnic hyperventilation, the washout time of sevoflurane anaesthesia was one-third compared to normal ventilation. The method for isocapnic hyperventilation described can potentially be transferred to a clinical setting with the intention to decrease emergence time from inhalation anaesthesia.

Radiographic Findings after Cricopharyngeal Myotomy

Single film examinations (iodine and/or barium) were reviewed in 28 patients who had undergone surgery on the cricopharyngeal muscle due to Zenker diverticula (24 patients), cricopharyngeal muscle incoordination (3 patients) and pharyngoesophageal web (one patient). All patients had had a myotomy which included the cricopharyngeal muscle and up to 3 cm of the cervical esophagus. Lateral and anterior deviation of the pharynx and cervical esophagus occurred regularly. A pharyngocutaneous fistula developed in 2 patients which healed within 3 weeks. In 5 patients there was a posterior leak of contrast medium during the first postoperative week which healed within 2 weeks. Six of these seven patients with a fistula or a leak had had either a diverticulum removed or sustained an accidental mucosal perforation. No patient had recurrence of diverticula, although, 9 patients developed a cricopharyngeal muscle impression. Iodine and barium examinations are important for monitoring early and late postoperative changes after cricopharyngeus myotomy.

Incidence, clinical presentation and mortality of liver cirrhosis in Southern Sweden: a 10-year population-based study

BACKGROUND

In Sweden, the most common causes of liver cirrhosis are alcohol overconsumption and hepatitis C. However, recent data on the clinical characteristics of Swedish patients with cirrhosis are scarce.

AIMS

To determine the incidence, clinical presentation, aetiological spectrum and survival rates of liver cirrhosis in Southern Sweden from 2001 to 2011.

METHODS

We used population-based medical registries to conduct a cohort study of all patients with liver cirrhosis in the southernmost region of Sweden with a population of 1.17 million. Medical records and histopathology data were reviewed. Patients were classified according to aetiology, and clinical parameters were registered. Patients were followed until death or December 2014.

RESULTS

A total of 1317 patients with cirrhosis were identified. The crude annual incidence of cirrhosis was estimated at 14.1/100 000. The most common aetiology was alcohol overconsumption with or without additional causes of cirrhosis (58%) followed by HCV alone (13%) and cryptogenic cirrhosis (12%). At diagnosis, ascites occurred in 43%, variceal bleeding in 6% and overt encephalopathy in 4%. The median follow-up was 4.3 years. The total 1-, 5- and 10-year survival rates were 79%, 47% and 27% respectively. Survival rates were better for women than for men. A 10-year cumulative incidence of transplantation was 7.3%. Mortality was worst for alcoholic cirrhosis with concomitant HCV when adjusted for age and gender.

CONCLUSIONS

Sweden continues to have a low incidence of cirrhosis compared with other European countries. Mortality varies with gender, aetiology and severity at diagnosis. Patients with alcoholic cirrhosis with concomitant HCV infection fare worst.

A simple method for isocapnic hyperventilation evaluated in a lung model

BACKGROUND

Isocapnic hyperventilation (IHV) has the potential to increase the elimination rate of anaesthetic gases and has been shown to shorten time to wake-up and post-operative recovery time after inhalation anaesthesia. In this bench test, we describe a technique to achieve isocapnia during hyperventilation (HV) by adding carbon dioxide (CO2) directly to the breathing circuit of a standard anaesthesia apparatus with standard monitoring equipment.

METHODS

Into a mechanical lung model, carbon dioxide was added to simulate a CO2 production (V(CO2)) of 175, 200 and 225 ml/min. Dead space (V(D)) volume could be set at 44, 92 and 134 ml. From baseline ventilation (BLV), HV was achieved by doubling the minute ventilation and fresh gas flow for each level of V(CO2), and dead space. During HV, CO2 was delivered (D(CO2)) by a precision flow meter via a mixing box to the inspiratory limb of the anaesthesia circuit to achieve isocapnia.

RESULTS

During HV, the alveolar ventilation increased by 113 ± 6%. Tidal volume increased by 20 ± 0.1% during IHV irrespective of V(D) and V(CO2) level. D(CO2) varied between 147 ± 8 and 325 ± 13 ml/min. Low V(CO2) and large V(D) demanded a greater D(CO2) administration to achieve isocapnia. The FICO2 level during IHV varied between 2.3% and 3.3%.

CONCLUSION

It is possible to maintain isocapnia during HV by delivering carbon dioxide through a standard anaesthesia circuit equipped with modern monitoring capacities. From alveolar ventilation, CO2 production and dead space, the amount of carbon dioxide that is needed to achieve IHV can be estimated.

Association between high dietary intake of the n-3 polyunsaturated fatty acid docosahexaenoic acid and reduced risk of Crohn's disease

BACKGROUND

There are plausible mechanisms for how dietary docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid, could prevent Crohn's disease (CD).

AIM

To conduct a prospective study to investigate the association between increased intake of DHA and risk of CD.

METHODS

Overall, 229 702 participants were recruited from nine European centres between 1991 and 1998. At recruitment, dietary intakes of DHA and fatty acids were measured using validated food frequency questionnaires. The cohort was monitored through to June 2004 to identify participants who developed incident CD. In a nested case-control analysis, each case was matched with four controls; odds ratios (ORs) were calculated for quintiles of DHA intake, adjusted for total energy intake, smoking, other dietary fatty acids, dietary vitamin D and body mass index.

RESULTS

Seventy-three participants developed incident CD. All higher quintiles of DHA intake were inversely associated with development of CD; the highest quintile had the greatest effect size (OR = 0.07; 95% CI = 0.02-0.81). The OR trend across quintiles of DHA was 0.54 (95% CI = 0.30-0.99, Ptrend  = 0.04). Including BMI in the multivariate analysis, due to its correlation with dietary fat showed similar associations. There were no associations with the other dietary fatty acids studied.

CONCLUSION

There were inverse associations, with a biological gradient between increasing dietary docosahexaenoic acid intakes and incident Crohn's disease. Further studies in other populations should measure docosahexaenoic acid to determine if the association is consistent and the hypothesis tested in randomised controlled trials of purely docosahexaenoic acid supplementation.

The management of iron deficiency in inflammatory bowel disease--an online tool developed by the RAND/UCLA appropriateness method

BACKGROUND

Iron deficiency is a common and undertreated problem in inflammatory bowel disease (IBD).

AIM

To develop an online tool to support treatment choice at the patient-specific level.

METHODS

Using the RAND/UCLA Appropriateness Method (RUAM), a European expert panel assessed the appropriateness of treatment regimens for a variety of clinical scenarios in patients with non-anaemic iron deficiency (NAID) and iron deficiency anaemia (IDA). Treatment options included adjustment of IBD medication only, oral iron supplementation, high-/low-dose intravenous (IV) regimens, IV iron plus erythropoietin-stimulating agent (ESA), and blood transfusion. The panel process consisted of two individual rating rounds (1148 treatment indications; 9-point scale) and three plenary discussion meetings.

RESULTS

The panel reached agreement on 71% of treatment indications. 'No treatment' was never considered appropriate, and repeat treatment after previous failure was generally discouraged. For 98% of scenarios, at least one treatment was appropriate. Adjustment of IBD medication was deemed appropriate in all patients with active disease. Use of oral iron was mainly considered an option in NAID and mildly anaemic patients without disease activity. IV regimens were often judged appropriate, with high-dose IV iron being the preferred option in 77% of IDA scenarios. Blood transfusion and IV+ESA were indicated in exceptional cases only.

CONCLUSIONS

The RUAM revealed high agreement amongst experts on the management of iron deficiency in patients with IBD. High-dose IV iron was more often considered appropriate than other options. To facilitate dissemination of the recommendations, panel outcomes were embedded in an online tool, accessible via http://ferroscope.com/.

Fatigue in out-patients with inflammatory bowel disease is common and multifactorial

BACKGROUND

Patients with inflammatory bowel disease (IBD) often complain of fatigue.

AIM

To investigate the prevalence and characteristics of fatigue among IBD out-patients in Scandinavia and to provide normative values for fatigue in IBD patients.

METHODS

A cross-sectional study was conducted on 425 IBD patients from six out-patient centres in Denmark, Norway and Sweden. Fatigue was measured using the Multidimensional Fatigue Inventory. The patients were also screened for anaemia and iron deficiency. Each centre included approximately 5% of their IBD cohort. The patients were enrolled consecutively from the out-patient clinics, regardless of disease activity and whether the visit was scheduled. The fatigue analysis was stratified for age and gender.

RESULTS

Using the 95th percentile of the score of the general population as a cut-off, approximately 44% of the patients were fatigued. When comparing the IBD patients with disease activity to the IBD patients in remission, all dimensions of fatigue were statistically significant (P < 0.05). Being anaemic or iron deficient was not associated with increased fatigue. Being a male patient with ulcerative colitis treated with corticosteroids was a strong determinant for increased fatigue. The normative ranges for IBD fatigue were calculated.

CONCLUSIONS

Fatigue in IBD is common regardless of anaemia or iron deficiency. Fatigue in IBD is most marked for patients < 60 years of age. Stratifying for gender and age is necessary when analysing fatigue, as fatigue is expressed differently between groups.

Oral clefts and behavioral health of young children

OBJECTIVES

This study examined the behavioral health of young children with oral clefts, and effects of satisfaction with facial appearance, cleft team care, number of cleft-related surgeries, and socioeconomic status (SES).

SUBJECTS AND METHODS

The study included a population-based sample of 104 children aged 2-12 years with isolated oral clefts from the state of Iowa. Behavior was evaluated with the Child Behavior Checklist or the Pediatric Behavior Scale 30, depending on age, compared with normative samples.

RESULTS

Risks of behavioral problems were not significantly different from normative samples except for higher inattention/hyperactivity risks at age 6-12 years. Low satisfaction with facial appearance was associated with behavioral problems in all domains, except aggression. Team-care effects were not associated with behavioral problems. Number of cleft-related surgeries was associated with increased anxiety/depression and somatic symptom risks. Higher SES was associated with reduced inattention/hyperactivity, aggressive/oppositional behavior, and somatic symptoms.

CONCLUSIONS

Most children with oral clefts may have similar behavioral health outcomes to unaffected children, except for increased inattention/hyperactivity risks at older ages. However, low satisfaction with facial appearance, increased exposure to surgeries, and lower SES may significantly increase behavioral problems. Also, the findings emphasize the need to study the representation of behavioral health professionals on cleft teams and access to behavioral health care.

End-expiratory lung volume and ventilation distribution with different continuous positive airway pressure systems in volunteers

BACKGROUND

Continuous positive airway pressure (CPAP) has been shown to improve oxygenation and a number of different CPAP systems are available. The aim of this study was to assess lung volume and ventilation distribution using three different CPAP techniques.

METHODS

A high-flow CPAP system (HF-CPAP), an ejector-driven system (E-CPAP) and CPAP using a Servo 300 ventilator (V-CPAP) were randomly applied at 0, 5 and 10 cmH₂O in 14 volunteers. End-expiratory lung volume (EELV) was measured by N₂ dilution at baseline; changes in EELV and tidal volume distribution were assessed by electric impedance tomography.

RESULTS

Higher end-expiratory and mean airway pressures were found using the E-CPAP vs. the HF-CPAP and the V-CPAP system (P<0.01). EELV increased markedly from baseline, 0 cmH₂O, with increased CPAP levels: 1110±380, 1620±520 and 1130±350 ml for HF-, E- and V-CPAP, respectively, at 10 cmH₂O. A larger fraction of the increase in EELV occurred for all systems in ventral compared with dorsal regions (P<0.01). In contrast, tidal ventilation was increasingly directed toward dorsal regions with increasing CPAP levels (P<0.01). The increase in EELV as well as the tidal volume redistribution were more pronounced with the E-CPAP system as compared with both the HF-CPAP and the V-CPAP systems (P<0.05) at 10 cmH₂O.

CONCLUSION

EELV increased more in ventral regions with increasing CPAP levels, independent of systems, leading to a redistribution of tidal ventilation toward dorsal regions. Different CPAP systems resulted in different airway pressure profiles, which may result in different lung volume expansion and tidal volume distribution.

Prolonged moderate pressure recruitment manoeuvre results in lower optimal positive end-expiratory pressure and plateau pressure

BACKGROUND

In acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), recruitment manoeuvres (RMs) are used frequently. In pigs with induced ALI, superior effects have been found using a slow moderate-pressure recruitment manoeuvre (SLRM) compared with a vital capacity recruitment manoeuvre (VICM). We hypothesized that the positive recruitment effects of SLRM could also be achieved in ALI/ARDS patients. Our primary research question was whether the same compliance could be obtained using lower RM pressure and subsequent positive end-expiratory pressure (PEEP). Secondly, optimal PEEP levels following the RMs were compared, and the use of volume-dependent compliance (VDC) to identify successful lung recruitment and optimal PEEP was evaluated.

PATIENTS AND METHODS

We performed a prospective randomised cross-over study where 16 ventilated patients with early ALI/ARDS each were subjected to the two RMs, followed by decremental PEEP titration. Volume-dependent initial, middle and final compliance (C(ini) , C(mid) and C(fin) ) were determined. Electric impedance tomography and end-expiratory lung volume measurements were used to follow lung volume changes.

RESULTS

The maximum response in compliance, PaO₂/FIO₂, venous admixture and C(ini) /C(fin) after recruitment, during decremental PEEP, was at significantly lower PEEP and plateau pressure after SLRM than VICM. Fewer patients responded in gas exchange after the SLRM, which was not the case for lung mechanics. The response in C(ini) was more pronounced than in conventional compliance.

CONCLUSIONS

The same compliance increase is achieved with SLRM as with VICM, and lower PEEP can be used, with correspondingly lower plateau pressures. VDC seems promising to identify successful recruitment and optimal PEEP.

A new non-radiological method to assess potential lung recruitability: a pilot study in ALI patients

INTRODUCTION

Potentially recruitable lung has been assessed previously in patients with acute lung injury (ALI) by computed tomography. A large variability in lung recruitability was observed between patients. In this study, we assess whether a new non-radiological bedside technique could determine potentially recruitable lung volume (PRLV) in ALI patients.

METHODS

Sixteen mechanically ventilated patients with early ALI/ARDS were subjected to a recruitment manoeuvre and decremental PEEP titration. Electric impedance tomography, together with measurements of end-expiratory lung volume (EELV) and tracheal pressure, were used to determine PRLV. The method defines fully recruited open lung volume (OLV) as the volume reached at the end of two consecutive vital capacity manoeuvres to 40 cmH₂O. It also uses extrapolation of the baseline alveolar pressure/volume curve up to 40 cmH₂O, the volume reached being the non-recruited lung volume. The difference between the fully recruited and the non-recruited volume was defined as PRLV.

RESULTS

We observed a considerable heterogeneity among the patients in lung recruitability, PRLV range 11-47%. In a post hoc analysis, dividing the patients into two groups, a high and a low PRLV group, we found at baseline before the recruitment manoeuvre that the high PRLV group had lower compliance and a lower fraction of EELV/OLV.

CONCLUSIONS

Using non-invasive radiation-free bedside methods, it may be possible to measure PRLV in ALI/ARDS patients. It is possible that this technique could be used to determine the need for recruitment manoeuvres and to select PEEP level on the basis of lung recruitability.

Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study

OBJECTIVE

Dietary linoleic acid, an n-6 polyunsaturated fatty acid, is metabolised to arachidonic acid, a component of colonocyte membranes. Metabolites of arachidonic acid have pro-inflammatory properties and are increased in the mucosa of patients with ulcerative colitis. The aim of this investigation was to conduct the first prospective cohort study investigating if a high dietary intake of linoleic acid increases the risk of developing incident ulcerative colitis.

DESIGN AND SETTING

Dietary data from food frequency questionnaires were available for 203 193 men and women aged 30-74 years, resident in the UK, Sweden, Denmark, Germany or Italy and participating in a prospective cohort study, the European Prospective Investigation into Cancer and Nutrition (EPIC). These participants were followed up for the diagnosis of ulcerative colitis. Each case was matched with four controls and the risk of disease calculated by quartile of intake of linoleic acid adjusted for gender, age, smoking, total energy intake and centre.

RESULTS

A total of 126 participants developed ulcerative colitis (47% women) after a median follow-up of 4.0 years (range, 1.7-11.3 years). The highest quartile of intake of linoleic acid was associated with an increased risk of ulcerative colitis (odds ratio (OR) = 2.49, 95% confidence interval (CI) = 1.23 to 5.07, p = 0.01) with a significant trend across quartiles (OR = 1.32 per quartile increase, 95% CI = 1.04 to 1.66, p = 0.02 for trend).

CONCLUSIONS

The data support a role for dietary linoleic acid in the aetiology of ulcerative colitis. An estimated 30% of cases could be attributed to having dietary intakes higher than the lowest quartile of linoleic acid intake.

A Scandinavian survey of drug administration through inhalation, suctioning and recruitment maneuvers in mechanically ventilated patients

BACKGROUND

The aim was to describe current practices for drug administration through inhalation, endotracheal suctioning and lung recruitment maneuvers in mechanically ventilated patients in Scandinavian intensive care units (ICUs).

METHODS

We invited 161 ICUs to participate in a web-based survey regarding (1) their routine standards and (2) current treatment of ventilated patients during the past 24 h. In order to characterize the patients, the lowest PaO(2) with the corresponding highest FiO(2), and the highest PaO(2) with the corresponding lowest FiO(2) during the 24-h study period were recorded.

RESULTS

Eighty-seven ICUs answered and reported 186 patients. Positive end-expiratory pressure (PEEP) levels (cmH(2)O) were 5-9 in 65% and >10 in 31% of the patients. Forty percent of the patients had heated humidification and 50% received inhalation of drugs. Endotracheal suctioning was performed >7 times during the study period in 40% of the patients, of which 23% had closed suction systems. Twenty percent of the patients underwent recruitment maneuvers. The most common recruitment maneuver was to increase PEEP and gradually increase the inspiratory pressure. Twenty-six percent of the calculated PaO(2)/FiO(2) ratios varied >13 kPa for the same patient.

CONCLUSION

Frequent use of drug administration through inhalation and endotracheal suctioning predispose to derecruitment of the lungs, possibly resulting in the large variations in PaO(2)/FiO(2) ratios observed during the 24-h study period. Recruitment maneuvers were performed only in one-fifth of the patients during the day of the survey.

Bioavailability of D-propoxyphene, acetyl salicylic acid, and phenazone in a combination tablet (Doleron): interindividual variation and influence of food intake

The influence of food intake on the bioavailability of three analgesic compounds--propoxyphene chloride, acetyl salicylic acid and phenazone--in a combination tablet, Doleron, has been examined in eight healthy volunteers. A single oral dose was given both on an empty stomach and together with a standardized breakfast meal. The plasma concentrations of propoxyphene, its major metabolite norpropoxyphene, salicylic acid and phenazone were determined by mass fragmentography, spectrofluorimetry and gas chromatography. Concomitant food intake had no consistent influence on the bioavailability of any of the components. Hence, doleron may be taken together with meals as well as between meals. Large interindividual variations in propoxyphene and phenazone concentrations were found, indicating that an optimal effect will not always be obtained by standard doses.

IgM deposition in skin biopsies from patients with primary biliary cirrhosis

Immunofluorescence studies on skin biopsies from 14 patients with primary biliary cirrhosis (PBC) showed granular papillary deposition of IgM in all. In addition, 6 patients had C3 deposition. Control patients with various other liver diseases, idiopathic high plasma levels of igM and extrahepatic cholestasis were only sporadically positive for IgM and not at all for C3. IgM deposition in dermal papillae in PBC does not merely reflect high plasma IgM levels or cholestasis but probably represents an immunochemically abnormal IgM population.

Clinical and immunological features of Sjögren's syndrome in patients with primary biliary cirrhosis with emphasis on focal sialadenitis

Serological and pathological findings in 21 patients with primary Sjögren's syndrome (primary SS) were compared with those in 32 patients with primary biliary cirrhosis (PBC). In ELISA, anti-SS-B/La antibodies were detected in sera from 14 (67%) of the patients with primary SS, but only from 12 (38%) of those with PBC. With the Ouchterlony test, anti-SS-A/Ro antibodies were found in sera from 15 (71%) of the primary SS patients, but in no PBC patient. Of those PBC patients investigated prospectively with objective tests, four of 11 (36%) had keratoconjunctivitis sicca, and five of 15 (33%) had pathological sialometry results. In contrast, all PBC patients but one (i.e., 14 of 15 or 93%) showed evidence of focal sialadenitis. In immunochemical study of PBC patients, IgM immunoreactivity was found in the stroma, particularly adjacent to excretory ducts and acini in salivary glands (5 of 5), whereas no such IgM deposits were observed in patients with primary SS (3 of 3), nor in healthy controls (n = 20). We conclude that the frequency of anti-SS-A/Ro and anti-SS-B/La antibodies in serum is lower in PBC patients than in patients with primary SS. The incidence of focal sialadenitis is high in PBC, though only one third of the PBC patients studied here showed clinical evidence of glandular dysfunction. With immunochemical techniques, sialadenitis associated with PBC is distinguishable by its significant IgM reaction from sialadenitis in primary SS.

Bronchoscopic suctioning may cause lung collapse: a lung model and clinical evaluation

OBJECTIVE

To assess lung volume changes during and after bronchoscopic suctioning during volume or pressure-controlled ventilation (VCV or PCV).

DESIGN

Bench test and patient study.

PARTICIPANTS

Ventilator-treated acute lung injury (ALI) patients.

SETTING

University research laboratory and general adult intensive care unit of a university hospital.

INTERVENTIONS

Bronchoscopic suctioning with a 12 or 16 Fr bronchoscope during VCV or PCV.

MEASUREMENTS AND RESULTS

Suction flow at vacuum levels of -20 to -80 kPa was measured with a Timeter(trade mark) instrument. In a water-filled lung model, airway pressure, functional residual capacity (FRC) and tidal volume were measured during bronchoscopic suctioning. In 13 ICU patients, a 16 Fr bronchoscope was inserted into the left or the right main bronchus during VCV or PCV and suctioning was performed. Ventilation was monitored with electric impedance tomography (EIT) and FRC with a modified N(2) washout/in technique. Airway pressure was measured via a pressure line in the endotracheal tube. Suction flow through the 16 Fr bronchoscope was 5 l/min at a vacuum level of -20 kPa and 17 l/min at -80 kPa. Derecruitment was pronounced during suctioning and FRC decreased with -479+/-472 ml, P<0.001.

CONCLUSIONS

Suction flow through the bronchoscope at the vacuum levels commonly used is well above minute ventilation in most ALI patients. The ventilator was unable to deliver enough volume in either VCV or PCV to maintain FRC and tracheal pressure decreased below atmospheric pressure.

Identification of aberrant forms of alkaline sphingomyelinase (NPP7) associated with human liver tumorigenesis

Alkaline sphingomyelinase (alk-SMase) is expressed in the intestine and human liver. It may inhibit colonic tumorigenesis, and loss of function mutations have been identified in human colon cancer. The present study investigates its expression in human liver cancer. In HepG2 liver cancer cells, RT–PCR identified three transcripts with 1.4, 1.2 and 0.4 kb, respectively. The 1.4 kb form is the wild-type cDNA with five translated exons, the 1.2 kb product lacks exon 4 and the 0.4 kb form is a combination of exons 1 and 5. Genomic sequence showed that these aberrant transcripts were products of alternative splicing. Transient expression of the 1.2 kb form showed no alk-SMase activity. In HepG2 cells, the alk-SMase activity is low in monolayer condition and increased with cell polarisation. Coexistence of 1.4 and 1.2 kb forms was also identified in one hepatoma biopsy. GenBank search identified a cDNA clone from human liver tumour, which codes a protein containing full length of alk-SMase plus a 73-amino-acid tag at the N terminus. The aberrant form was translated by an alternative starting codon upstream of the wild-type mRNA. Expression study showed that linking the tag markedly reduced the enzyme activity. We also analysed human liver biopsy samples and found relatively low alk-SMase activity in diseases with increased risk of liver tumorigenesis. In conclusion, expression of alk-SMase is changed in hepatic tumorigenesis, resulting in loss or marked reduction of the enzyme function.

Acute liver failure in Sweden: etiology and outcome

OBJECTIVE

To determine the causes and outcome of all patients with acute liver failure (ALF) in Sweden 1994-2003 and study the diagnostic accuracy of King's College Hospital (KCH) criteria and the model for end-stage liver disease (MELD) score with transplant-free deaths as a positive outcome.

RESEARCH DESIGN AND METHODS

Adult patients in Sweden with international normalized ratio (INR) of >or=1.5 due to severe liver injury with and without encephalopathy at admission between 1994-2003 were included.

RESULTS

A total of 279 patients were identified. The most common cause of ALF were acetaminophen toxicity in 42% and other drugs in 15%. In 31 cases (11%) no definite etiology could be established. The KCH criteria had a positive-predictive value (PPV) of 67%, negative-predictive value (NPV) of 84% in the acetaminophen group. Positive-predictive value and negative-predictive value of KCH criteria in the nonacetaminophen group were 54% and 63% respectively. MELD score>30 had a positive-predictive value of 21%, negative-predictive value of 94% in the acetaminophen group. The corresponding figures for the nonacetaminophen group were 64% and 76% respectively.

CONCLUSIONS

Acetaminophen toxicity was the most common cause in unselected patients with ALF in Sweden. KCH criteria had a high NPV in the acetaminophen group, and in combination with MELD score<30 predicts a good prognosis in acetaminophen patients without transplantation.

Health promotion for people with disabilities: development and evaluation of the Living Well with a Disability program

People with disabilities can benefit from health promotion opportunities to reduce the incidence and severity of secondary conditions that further limit their participation in society. This paper describes participatory action research (PAR) methods we used to develop, implement and evaluate the Living Well with a Disability program. Community-based agencies that provide information and referral services to people with disabilities (independent living centers funded under Title VII, Rehabilitation Act) recruited a convenience sample of 246 people with mobility impairments to participate in a randomly assigned, wait-list control health promotion intervention study. Paper-and-pencil outcome measures included the secondary conditions surveillance instrument, unhealthy days and health care utilization. Logistic regression on outcomes controlling for demographic variables and pre-test measures indicated reductions in all three outcome variables. People with mobility impairments who participated in the Living Well with a Disability program reported less limitation from secondary conditions, fewer unhealthy days and less health care utilization. PAR methods are particularly important to design useful interventions for this population.

Regional lung derecruitment after endotracheal suction during volume- or pressure-controlled ventilation: a study using electric impedance tomography

OBJECTIVE

To assess lung volume and compliance changes during open- and closed-system suctioning using electric impedance tomography (EIT) during volume- or pressure-controlled ventilation.

DESIGN AND SETTING

Experimental study in a university research laboratory.

SUBJECTS

Nine bronchoalveolar saline-lavaged pigs.

INTERVENTIONS

Open and closed suctioning using a 14-F catheter in volume- or pressure-controlled ventilation at tidal volume 10 ml/kg, respiratory rate 20 breaths/min, and positive end-expiratory pressure 10 cmH2O.

MEASUREMENTS AND RESULTS

Lung volume was monitored by EIT and a modified N2 washout/-in technique. Airway pressure was measured via a pressure line in the endotracheal tube. In four ventral-to-dorsal regions of interest regional ventilation and compliance were calculated at baseline and 30 s and 1, 2, and 10 min after suctioning. Blood gases were followed. At disconnection functional residual capacity (FRC) decreased by 58+/-24% of baseline and by a further 22+/-10% during open suctioning. Arterial oxygen tension decreased to 59+/-14% of baseline value 1 min after open suctioning. Regional compliance deteriorated most in the dorsal parts of the lung. Restitution of lung volume and compliance was significantly slower during pressure-controlled than volume-controlled ventilation.

CONCLUSIONS

EIT can be used to monitor rapid lung volume changes. The two dorsal regions of the lavaged lungs are most affected by disconnection and suctioning with marked decreases in compliance. Volume-controlled ventilation can be used to rapidly restitute lung aeration and oxygenation after lung collapse induced by open suctioning.

Slow moderate pressure recruitment maneuver minimizes negative circulatory and lung mechanic side effects: evaluation of recruitment maneuvers using electric impedance tomography

OBJECTIVE

To evaluate the efficacy of different lung recruitment maneuvers using electric impedance tomography.

DESIGN AND SETTING

Experimental study in animal model of acute lung injury in an animal research laboratory.

SUBJECTS

Fourteen pigs with saline lavage induced lung injury.

INTERVENTIONS

Lung volume, regional ventilation distribution, gas exchange, and hemodynamics were monitored during three different recruitment procedures: (a) vital capacity maneuver to an inspiratory pressure of 40 cmH2O (ViCM), (b) pressure-controlled recruitment maneuver with peak pressure 40 and PEEP 20 cmH2O, both maneuvers repeated three times for 30 s (PCRM), and (c) a slow recruitment with PEEP elevation to 15 cmH2O with end inspiratory pauses for 7 s twice per minute over 15 min (SLRM).

MEASUREMENTS AND RESULTS

Improvement in lung volume, compliance, and gas exchange were similar in all three procedures 15 min after recruitment. Ventilation in dorsal regions of the lungs increased by 60% as a result of increased regional compliance. During PCRM compliance decreased by 50% in the ventral region. Cardiac output decreased by 63+/-4% during ViCM, 44+/-2% during PCRM, and 21+/-3% during SLRM.

CONCLUSIONS

In a lavage model of acute lung injury alveolar recruitment can be achieved with a slow lower pressure recruitment maneuver with less circulatory depression and negative lung mechanic side effects than with higher pressure recruitment maneuvers. With electric impedance tomography it was possible to monitor lung volume changes continuously.

Combined oral and enema treatment with Pentasa (mesalazine) is superior to oral therapy alone in patients with extensive mild/moderate active ulcerative colitis: a randomised, double blind, placebo controlled study

BACKGROUND AND AIMS

Oral aminosalicylates are well established in the treatment of active mild/moderate ulcerative colitis (UC) when the disease is extensive (that is, beyond the splenic flexure). The majority of clinical symptoms relate to disease activity in the distal part of the colon and therefore this study was designed to investigate if adding a mesalazine enema to oral mesalazine has additional benefit for patients with extensive mild/moderate active UC.

METHODS

A randomised double blind study was performed in 127 ambulatory patients. All received 4 g/day (twice daily dosing) oral mesalazine for eight weeks. During the initial four weeks, they additionally received an enema at bedtime containing 1 g of mesalazine or placebo. Disease activity was assessed using the ulcerative colitis disease activity index, with clinical and endoscopic signs at four and eight weeks.

RESULTS

Remission was obtained in 44% (95% confidence interval (CI) 31%, 58%) of the mesalazine enema group (Me) and in 34% (95% CI 21%, 49%) of the placebo enema group (Pl) at four weeks (p = 0.31) and in 64% (95% CI 50%, 76%) of the Me group versus 43% (95% CI 28%, 58%) of the Pl group at eight weeks (p = 0.03). Improvement was obtained in 89% (95% CI 78%, 96%) of the Me group versus 62% (95% CI 46%, 75%) of the Pl group at four weeks (p = 0.0008) and in 86% (95% CI 75%, 94%) of the Me group versus 68% (95% CI 53%, 81%) of the Pl group at eight weeks (p = 0.026).

CONCLUSION

In patients with extensive mild/moderate active UC, the combination therapy is superior to oral therapy. It is safe, well accepted, and may be regarded as firstline treatment.

The X4 phenotype of HIV type 1 evolves from R5 in two children of mothers, carrying X4, and is not linked to transmission

Previously, we found that emergence of the X4 viral phenotype in HIV-1-infected children was related to the presence of X4 in their mothers (C.H. Casper et al., J Infect Dis 2002; 186:914-921). Here, we investigated the origin of the X4 phenotype in the child, analyzing two mother-child pairs (Ma-Ca, Mb-Cb) where the mothers carried X4 and their children developed X4 after an initial presence of R5. We used nested polymerase chain reaction of the env V3 region to generate 203 HIV-1 clones for sequencing (Ma, n = 44; Ca, n = 73; Mb, n = 61; Cb, n = 25) from DNA of peripheral blood mononuclear cell (PBMC) lysates, altogether 167 clones, or from cDNA of plasma RNA, 36 clones. PBMC and plasma isolate sequences from each time point enabled us to assign the probable phenotype to clone sequences in a phylogenetic tree. The transmission and evolution were reconstructed using the maximum likelihood method. In mother-child pair Ma-Ca, one maternal R5 isolate clustered with the child's R5 sequences, at the earliest time when R5 was isolated in the child, confirming this as a likely source of the transmitted R5 phenotype. At age 3, an X4 population was present in the child that had evolved from the child's own R5-associated population, clearly distinct from the maternal X4 sequences. The second mother-child pair (Mb-Cb) displayed a similar pattern. Amino acid substitution patterns corroborated the conclusions from the phylogenetic tree. Thus, in both children, the X4 virus developed from their own R5 population, and was not caused by transmission of X4.

Haplotypes of the interleukin-4 receptor alpha chain gene associate with susceptibility to and severity of atopic asthma

BACKGROUND

Development of asthma is likely to depend on a complex interaction between environmental and genetic factors. Several groups have suggested the gene of the IL-4 receptor alpha chain (IL4R) as a candidate gene for the development of asthma, although association with single polymorphisms has shown contradicting results.

OBJECTIVE

We chose to analyse IL4R gene haplotypes and assess their possible relevance in susceptibility to asthma and to certain clinical phenotypes.

METHODS

IL4R gene haplotypes were analysed, based on the three markers C-3223T, Q551R and I50V, using the expectation-maximization algorithm, in 170 atopic asthma patients and 350 controls, all adult Swedish Caucasians.

RESULTS

Our data showed significantly higher levels of soluble IL-4R (sIL-4R) in asthma patients compared with controls (P<0.0001). Furthermore, we showed a significant association between the IL4R haplotype containing the alleles T-3223, V50 and R551 (TVR) of the IL4R gene, and susceptibility to atopic asthma, with a frequency of 6.5% in the patients compared with 1% in the controls (P<0.0005). A subgroup of patients with heterozygous or homozygous state for the T-3223, V50 and R551 alleles, also had lower levels of sIL-4R in their circulation compared with patients with homozygous state in the C-3223, I50 and Q551 alleles (P<0.05) and showed less severe asthma according to lung function test (P<0.05). Analysis of single markers showed the T-3223 IL4R allele to associate with lower serum levels of sIL-4 receptor (P<0.0001) and patients carrying the T allele also had more symptoms of active asthma (wheezing, P<0.01; coughing, P<0.05 and breathing difficulties, P<0.01).

CONCLUSION

Our data suggest that asthmatic patients with low levels of sIL-4 receptor may represent a genetically distinct subgroup of atopic asthma. TVR haplotype analyses confirm the importance of IL4R as a candidate gene for susceptibility to asthma. This finding may have implications for the understanding of the pathogenesis of asthma and possibly for the development of more specific therapies.

GB virus C coinfection and vertical transmission in HIV-infected mothers before the introduction of antiretroviral prophylaxis

OBJECTIVES

To investigate the prevalence of GB virus C (GBV-C) viraemia and GBV-C antibodies in a cohort of HIV-infected mothers and their infants between 1987 and 1994.

METHODS

GBV-C viraemia and antibodies were determined by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) in 52 HIV-infected mothers and their 53 infants, who were born before antiretroviral prophylaxis for reduction of HIV transmission was introduced at the end of 1994. Ten of these children acquired HIV.

RESULTS

Mothers of three children had GBV-C viraemia and mothers of another 14 children carried antibodies against GBV-C. No mother had GBV-C antibodies and GBV-C viraemia simultaneously. GBV-C viraemia was detected in only one infant. This child was delivered by the vaginal route to a mother with GBV-C viraemia, and was not HIV-infected. No vertical transmission of GBV-C occurred from mothers with GBV-C antibodies. However, four of 10 children who were infected with HIV had a mother with past or ongoing GBV-C infection.

CONCLUSION

Our findings suggest that the risk of vertical transmission of GBV-C is not elevated in HIV-infected mothers. Furthermore, although the number of HIV-1-infected children was low, we saw no evidence that the presence of ongoing or past GBV-C infection influenced the probability of vertical HIV transmission.

Tracheal double-lumen ventilation attenuates hypercapnia and respiratory acidosis in lung injured pigs

OBJECTIVE

Evaluation of ventilatory and circulatory effects with coaxial double-lumen tube ventilation for dead-space reduction as compared with standard endotracheal tube ventilation.

DESIGN

Experimental study in a pig model of lung lavage induced acute lung injury.

SETTING

University research laboratory.

MEASUREMENTS AND RESULTS

Tidal volumes of 6, 8 and 10 ml/kg body weight with a set respiratory rate of 20 breaths per minute were used in a random order with both double-lumen ventilation and standard endotracheal tube ventilation. Measurements of ventilatory and circulatory parameters were obtained after steady state at each experimental stage. With a tidal volume of 6 ml/kg, PaCO(2) was reduced from 10.9 kPa (95% CI 9.0-12.9) with a standard endotracheal tube to 8.2 kPa (95% CI 7.0-9.4) with double-lumen ventilation. This corresponds to a reduction in carbon dioxide levels by 25%. At 6 ml/kg, pH increased from 7.17 (95% CI 7.09-7.24) with a standard endotracheal tube to 7.27 (95% CI 7.21-7.32) with double-lumen ventilation. Tracheal pressure was monitored continuously and no difference between single- or double-lumen ventilation was noted at corresponding levels of ventilation. There was no formation of auto-PEEP. Partial tube obstruction due to secretions was not observed during the experiments.

CONCLUSIONS

Coaxial double-lumen tube ventilation is an effective adjunct to reduce technical dead space. It attenuates hypercapnia and respiratory acidosis in a lung injury pig model.

Effectiveness and side effects of closed and open suctioning: an experimental evaluation

OBJECTIVE

To compare the effectiveness of closed system suctioning (CSS) and open system suctioning (OSS) and the side effects on gas exchange and haemodynamics, during pressure-controlled ventilation (PCV) or continuous positive airway pressure (CPAP).

DESIGN

Bench test and porcine lung injury model.

PARTICIPANTS

Twelve bronchoalveolar saline-lavaged pigs.

SETTING

Research laboratory in a university hospital.

INTERVENTIONS

In a mechanical lung, the efficacy of OSS and CSS with 12 and 14 Fr catheters were compared during volume-control ventilation, PCV, CPAP 0 or 10 cmH(2)O by weighing the suction system before and after aspirating gel in a transparent trachea. Side effects were evaluated in the animals with the same ventilator settings during suctioning of 5, 10 or 20 s duration.

MEASUREMENTS AND RESULTS

Suctioning with 12 and 14 Fr catheters was significantly more efficient with OSS (1.9+/-0.1, 2.8+/-0.9 g) and with CSS during CPAP 0 cmH(2)O (1.8+/-0.2, 4.2+/-0.5 g) as compared to CSS during PCV (0.2+/-0.2, 0.8+/-0.3 g) or CPAP 10 cmH(2)O (0.0+/-0.1, 0.7+/-0.4 g), p<0.01 (means +/- SD). OSS and CSS at CPAP 0 cmH(2)O resulted in a marked decrease in SpO(2), mixed venous oxygen saturation and tracheal pressure, p<0.001, but the side effects were considerably fewer during CSS with PCV and CPAP 10 cmH(2)O, p<0.05.

CONCLUSIONS

Irrespective of catheter size, OSS and CSS during CPAP 0 cmH(2)O were markedly more effective than CSS during PCV and CPAP 10 cmH(2)O but had worse side effects. However, the side effects lasted less than 5 min in this animal model. Suctioning should be performed effectively when absolutely indicated and the side effects handled adequately.

Multiple effects of alpha1-antitrypsin on breast carcinoma MDA-MB 468 cell growth and invasiveness

The degradation of extracellular matrix during cancer invasion results from the action of several protease and protease inhibitor systems. Alpha(1)-Antitrypsin (AAT) is a serine proteinase inhibitor produced by various tumour cells, and its plasma concentration rises during inflammation, infection and malignant diseases. AAT is found in a native, inhibitory active form, but also in other, non-inhibitory forms including cleaved and/or degraded. To test a hypothesis that AAT dependent on its molecular form may have multiple effects on tumour cell behaviour, breast cancer cells, MDA-MB 468, were cultured alone or stimulated with a native AAT or its C-terminal fragment (C-36) at a concentration of 5 micromol/l for 2, 24 and 48 hours. Native AAT added to the cells for 2 hours enhanced transforming growth factor beta 1 (TGFbeta1) levels by 50%, but inhibited cell proliferation (by 61%), reduced interleukin 6 (IL-6) levels (by 87%) and activity (by about 66%), compared with non-stimulated cells. Native AAT showed similar, but less pronounced, effects when added to the cells for 24 and 48 hours. Under the same experimental conditions the cells exposed to the C-36 peptide significantly increased in proliferation, invasiveness and showed higher IL-6 levels. In addition, cells treated with the C-36 for 48 hours increased in NFkappaB (nuclear factor kappa B) activity. These results indicate that AAT, dependent on its molecular form, can both suppress and induce breast tumour cell biological activity in vitro.