Identifying Risk Factors for Anthracycline Chemotherapy-induced Phlebitis in Women with Breast Cancer: An Observational Study

AIMS

Anthracycline chemotherapy administered via a peripheral cannula results in severe anthracycline chemotherapy-induced phlebitis (ACIP) in about 20-30% of patients. Administering chemotherapy via a central venous catheter (CVC) prevents ACIP. However, CVCs are associated with an increased risk of thrombosis and sepsis. Our aim was to identify risk factors associated with severe ACIP and to provide evidence about the individual risk of developing symptoms.

MATERIALS AND METHODS

A prospective observational study of 263 women with breast cancer receiving peripheral administration of anthracycline chemotherapy at a UK cancer centre was conducted between May 2016 and January 2018. Data were collected at baseline and every 3 weeks following each chemotherapy treatment, using both healthcare professional- and participant-reported symptom assessments.

RESULTS

After three cycles of chemotherapy, 27% of participants experienced severe ACIP. Factors associated with symptom severity were identified as: arm used for chemotherapy administration, epirubicin dose, age, pre-existing hypertension, comorbidity, ethnic group and pain during chemotherapy administration. The sequence of arm used for chemotherapy administration was the single most significant factor (P < 0.001). When alternating arms were used no other risk factor was influential. Where alternating arms were not used, younger age and higher dose were associated with higher-grade symptoms, with age being more influential than dose. The cumulative effect of increasing symptom severity with repeated cycles was also identified (P < 0.001).

CONCLUSION

It is recommended that a CVC is not routinely required for women with breast cancer who have not undergone an axillary node clearance and receive chemotherapy in alternate arms. The need for a CVC for women who are planned to receive all anthracycline chemotherapy cycles in the same arm should be assessed in the light of peripheral venous access assessment and the key risk factors of age, dose and number of cycles.

Printed titanium implants in UK craniomaxillofacial surgery. Part I: access to digital planning and perceived scope for use in common procedures

This first part of a two-part study examines perceived applications for and barriers to using printed titanium in light of current caseloads, funding pathways, and use of digital planning. It aims to demonstrate the scope for printed titanium in modern practice and to guide industry about the needs of UK surgeons. A cross-sectional study over 14 weeks was performed electronically with support from the British Association of Oral and Maxillofacial Surgeons (BAOMS) and a national trainee-led recruitment team. Ethics approval was obtained at the lead centre. A total of 132 participants joined the study (70% consultants, 25% specialty registrars, and 5% other), approximating a 29% response rate from consultant/registrar BAOMS members throughout mainland UK. Eighty-eight per cent used CAD-CAM design, with highly variable funding/access, design/manufacturing workflows (in-house/outsourced). Eighty-eight per cent were involved with trauma, 61% with orthognathic, and 52% with oncology-reconstruction surgery. Favourite applications for printed titanium were orbital floor repair (89%) and free-flap jaw reconstruction (87%). Most participants also cited maxillary/zygomatic osteotomies and cranioplasty (range 61%-73%). Although a popular application (78%), the evidence base in temporomandibular joint surgery is limited. Those performing orthognathic surgery perceived more indications than those who did not (p=0.013). Key barriers included cost, turnaround time and logistics, and the need to be trained in traditional techniques. Printed titanium was useful for both common and niche procedures, but was specifically limited in emergency trauma. Most surgeons had experience in CAD-CAM surgery but technical understanding appeared unclear. Limiting factors included variable funding and production pathways, perceived costs, and logistics, but in-house design can minimise them. In part II, we quantify perceived benefits and limitations and whether surgeons' understanding and knowledge are sufficient to rationalise them.

Printed titanium implants in UK craniomaxillofacial surgery. Part II: perceived performance (outcomes, logistics, and costs)

This second part explores perceptions and understanding of clinical performance, turnaround, and costs for printed titanium implants or plates in common procedures, evaluating both 'in-house' and 'outsourced' CAD-CAM pathways. A cross-sectional study, supported by the British Association of Oral and Maxillofacial Surgeons (BAOMS) and a national trainee-led recruitment team, was conducted over 14 weeks. A total of 132 participants took part (demographic data is reported in Part I). For fibular-flap mandibular reconstruction, most participants (69% - 91%) perceived printed titanium as superior to intraoperatively or preoperatively hand-bent plates for surgical duration, accuracy, dental restorability, and aesthetics. There was less agreement about complications and plate-failure risks. Most perceived printed plates to be superior to traditional wafer-based maxillary osteotomy for surgical duration (61%) and maxillary positioning (60%). For orbital floor repair, most perceived improvements in surgical duration (83%, especially higher-volume operators p=0.009), precision (84%), and ease of placement (69%). Rarely (less than 5%) was any outcome rated inferior to traditional techniques for any procedure. Perceived turnaround times and costs were variable, but the greatest consensus was for two-segment fibular-flap reconstructions and orbital floor repair. Industry estimates were generally consistent between two company representatives, but manufacturing-only costs differed when using in-house (departmental) designers. Costs and turnaround times are questionable barriers since few understand 'real-world' figures. Designing in-house can dramatically alter costs. Improved accuracy and surgical duration are common themes but biomechanical benefits are less-well understood. This study paints a picture of the potentially routine applications and benefits of printed titanium, capacity for uptake, understanding amongst surgeons, and areas for improvement.

Toward a high-throughput screening platform for directed evolution of enzymes that activate genotoxic prodrugs

Engineering of enzymes to more efficiently activate genotoxic prodrugs holds great potential for improving anticancer gene or antibody therapies. We report the development of a new, GFP-based, high-throughput screening platform to enable engineering of prodrug-activating enzymes by directed evolution. By fusing an inducible SOS promoter to an engineered GFP reporter gene, we were able to measure levels of DNA damage in intact Escherichia coli and separate cell populations by fluorescence activating cell sorting (FACS). In two FACS iterations, we were able to achieve a 90,000-fold enrichment of a functional prodrug-activating nitroreductase from a null library background.

Biomechanical strategies for accuracy and force generation during stone tool production

Multiple hominin species used and produced stone tools, and the archaeological record provides evidence that stone tool behaviors intensified among later members of the genus Homo. This intensification is widely thought to be the product of cognitive and anatomical adaptations that enabled later Homo taxa to produce stone tools more efficiently relative to earlier hominin species. This study builds upon recent investigations of the knapping motions of modern humans to test whether aspects of our upper limb anatomy contribute to accuracy and/or efficiency. Knapping kinematics were captured from eight experienced knappers using a Vicon motion capture system. Each subject produced a series of Oldowan bifacial choppers under two conditions: with normal wrist mobility and while wearing a brace that reduced wrist extension (∼30°-35°), simulating one aspect of the likely primitive hominin condition. Under normal conditions, subjects employed a variant of the proximal-to-distal joint sequence common to throwing activities: subjects initiated down-swing upper limb motion at the shoulder and proceeded distally, increasing peak linear and angular velocities from the shoulder to the elbow to the wrist. At the wrist, subjects utilized the 'dart-thrower's arc,' the most stable plane of radiocarpal motion, during which wrist extension is coupled with radial deviation and flexion with ulnar deviation. With an unrestrained wrist, subjects achieved significantly greater target accuracy, wrist angular velocities, and hand linear velocities compared with the braced condition. Additionally, the modern wrist's ability to reach high degrees of extension (≥28.5°) following strike may decrease risk of carpal and ligamentous damage caused by hyperextension. These results suggest that wrist extension in humans contributes significantly to stone tool-making performance.

A pilot study quantifying the shape of tidal breathing waveforms using centroids in health and COPD

During resting tidal breathing the shape of the expiratory airflow waveform differs with age and respiratory disease. While most studies quantifying these changes report time or volume specific metrics, few have concentrated on waveform shape or area parameters. The aim of this study was to derive and compare the centroid co-ordinates (the geometric centre) of inspiratory and expiratory flow-time and flow-volume waveforms collected from participants with or without COPD. The study does not aim to test the diagnostic potential of these metrics as an age matched control group would be required. Twenty-four participants with COPD and thirteen healthy participants who underwent spirometry had their resting tidal breathing recorded. The flow-time data was analysed using a Monte Carlo simulation to derive the inspiratory and expiratory flow-time and flow-volume centroid for each breath. A comparison of airflow waveforms show that in COPD, the breathing rate is faster (17 ± 4 vs 14 ± 3 min(-1)) and the time to reach peak expiratory flow shorter (0.6 ± 0.2 and 1.0 ± 0.4 s). The expiratory flow-time and flow-volume centroid is left-shifted with the increasing asymmetry of the expired airflow pattern induced by airway obstruction. This study shows that the degree of skew in expiratory airflow waveforms can be quantified using centroids.

Electromagnetic inductance plethysmography to measure tidal breathing in preterm and term infants

Tidal breathing measurements which provide a non-invasive measure of lung function in preterm and term infants are particularly useful to guide respiratory support. We used a new technique of electromagnetic inductance plethysmography (EIP) to measure tidal breathing in infants between 32 and 42 weeks postconceptional age (PCA). Tidal breathing was measured in 49 healthy spontaneously breathing infants between 32 and 42 weeks PCA. The weight-corrected tidal volume (V(T) ) and minute volume (MV) decreased with advancing PCA (V(T) 6.5 ± 1.5 ml/kg and MV 0.44 ± 0.04 L/kg/min at 32-33 weeks, respectively; 6.3 ± 0.9 ml/kg and 0.38 ± 0.02 L/kg/min at 34-36 weeks; and 5.1 ± 1.1 ml/kg and 0.28 ± 0.02 L/kg/min at term, V(T) P < 0.001 and MV P < 0.01 for 32-33 weeks PCA vs. term; V(T) P = 0.016 and MV P = 0.015 for 34-36 weeks PCA vs. term). Respiratory frequency and the phase angle decreased significantly with advancing PCA but the flow parameter t(PTEF) /t(E) did not change significantly. Using a new technique to measure tidal breathing parameters in newborn infants, our data confirms its usability in clinical practice and establishes normative data which can guide future respiratory management of newborn infants.

Estimation of tidal ventilation in preterm and term newborn infants using electromagnetic inductance plethysmography

Tidal volume (VT) measurements in newborn infants remain largely a research tool. Tidal ventilation and breathing pattern were measured using a new device, FloRight, which uses electromagnetic inductive plethysmography,and compared simultaneously with pneumotachography in 43 infants either receiving no respiratory support or continuous positive airway pressure (CPAP).Twenty-three infants were receiving CPAP (gestational age 28 ± 2 weeks, mean ± SD) and 20 were breathing spontaneously (gestational age 34 ± 4 weeks). The two methods were in reasonable agreement, with VT (r2 = 0.69) ranging from 5 to 23 ml (4–11 ml kg−1) with a mean difference of 0.4 ml and limit of agreement of −4.7 to + 5.5 ml. For respiratory rate, minute ventilation,peak flow and breathing pattern indices, the mean difference between the two methods ranged between 0.7% and 5.8%. The facemask increased the respiratory rate (P < 0.001) in both groups with the change in VT being more pronounced in the infants receiving no respiratory support. Thus, FloRight provides an easy to use technique to measure term and preterm infants in the clinical environment without altering the infant's breathing pattern.

Chemosensitivity of cardiac muscle

1. Measurements of contractions, conduction velocity and intracellular potential were made on isolated rabbit atria under four sets of conditions: high bicarbonate/high CO(2) (HH), low bicarbonate/low CO(2) (LL), high bicarbonate/low CO(2) (HL) and low bicarbonate/high CO(2) (LH). The ratio high/low was the same for the bicarbonate and CO(2) concentrations, so that HH had the same pH as LL.2. Acid solutions caused a fall of a few mV in the resting potential, but not in the overshoot. They reduced conduction velocity and rate of rise of the action potential. They depressed contractions, but prolonged the tail of the action potential.3. Alkaline solutions caused the converse changes, but, with the exception of the effect on the duration of the action potential, the relation with pH was markedly alinear, in that a rise in pH had much less effect than an equivalent fall.4. Statistical tests were devised to decide whether the observed changes were associated primarily with pH, P(CO(2) ) or bicarbonate. By far the strongest association was with external pH. Changes in P(CO(2) ), per se, had no significant effect.

Discovery and evaluation of Escherichia coli nitroreductases that activate the anti-cancer prodrug CB1954

Gene-directed enzyme prodrug therapy (GDEPT) aims to achieve highly selective tumor-cell killing through the use of tumor-tropic gene delivery vectors coupled with systemic administration of otherwise inert prodrugs. Nitroaromatic prodrugs such as CB1954 hold promise for GDEPT as they are readily reduced to potent DNA alkylating agents by bacterial nitroreductase enzymes (NTRs). Transfection with the nfsB gene from Escherichia coli can increase the sensitivity of tumor cells to CB1954 by greater than 1000-fold. However, poor catalytic efficiency limits the activation of CB1954 by NfsB at clinically relevant doses. A lack of flexible, high-throughput screening technology has hindered efforts to discover superior NTR candidates. Here we demonstrate how the SOS chromotest and complementary screening technologies can be used to evaluate novel enzymes that activate CB1954 and other bioreductive and/or genotoxic prodrugs. We identify the major E. coli NTR, NfsA, as 10-fold more efficient than NfsB in activating CB1954 as purified protein (k(cat)/K(m)) and when over-expressed in an E. coli nfsA(-)/nfsB(-) gene deleted strain. NfsA also confers sensitivity to CB1954 when expressed in HCT-116 human colon carcinoma cells, with similar efficiency to NfsB. In addition, we identify two novel E. coli NTRs, AzoR and NemA, that have not previously been characterized in the context of nitroaromatic prodrug activation.

Thermal screening of facial skin arterial hot spots using non-contact infrared radiometry

Non-contact infrared thermometry of facial skin offers advantages over less accessible internal body sites, especially when considering mass screening for febrile infectious disease. The forehead offers an obvious site, but does not present an isothermic surface, as various small arteries passing close to the surface create 'hot-spots'. The aim of this study is to use non-contact infrared (IR) thermometry to determine the link between the temperature at specific facial skin sites and clinical body temperature. A sample of 169 asymptomatic adults (age range 18-54 years) was screened with IR thermometers (Braun Thermoscan proLT for auditory meatus (AM) temperature representing clinical body temperature, and a Raytek, Raynger MX for skin surface temperature). Peak IR skin temperature was measured over the course of each posterior auricular artery (PAA) and each superficial temporal artery (STA). In a sub-group (n = 54) the peak skin temperature of the forehead's metopic region (MR) was also recorded. There were no differences (P > 0.05) between the PAA and STA at 34.2 +/- 0.9 degrees C and 34.2 +/- 0.7 degrees C, respectively, which were 2.5 degrees C cooler than the AM temperature (36.7 +/- 0.5 degrees C, p < 0.001). Although there was no correlation between AM and PAA or STA there was a correlation (r2 = 0.63, p < 0.001) between PAA and STA. There were no asymmetric temperature differences between the left and right sides and males had warmer skin over the MR (F, 33.6 +/- 0.7 degrees C versus M, 34.4 +/- 0.6 degrees C, p < 0.001). Although a lack of correlation between either PAA or STA and AM was apparent in asymptomatics, further research in symptomatics is required to determine the usefulness of these measurements in mass screening of conditions such as fever.

Human subtelomeres are hot spots of interchromosomal recombination and segmental duplication

Human subtelomeres are polymorphic patchworks of interchromosomal segmental duplications at the ends of chromosomes. Here we provide evidence that these patchworks arose recently through repeated translocations between chromosome ends. We assess the relative contribution of the principal mechanisms of ectopic DNA repair to the formation of subtelomeric duplications and find that non-homologous end-joining predominates. Once subtelomeric duplications arise, they are prone to homology-based sequence transfers as shown by the incongruent phylogenetic relationships of neighbouring sections. Interchromosomal recombination of subtelomeres is a potent force for recent change. Cytogenetic and sequence analyses reveal that pieces of the subtelomeric patchwork have changed location and copy number with unprecedented frequency during primate evolution. Half of the known subtelomeric sequence has formed recently, through human-specific sequence transfers and duplications. Subtelomeric dynamics result in a gene duplication rate significantly higher than the genome average and could have both advantageous and pathological consequences in human biology. More generally, our analyses suggest an evolutionary cycle between segmental polymorphisms and genome rearrangements.

Array Comparative Genomic Hybridization Analysis of Genomic Alterations in Breast Cancer Subtypes

In this study, we performed high-resolution array comparative genomic hybridization with an array of 4153 bacterial artificial chromosome clones to assess copy number changes in 44 archival breast cancers. The tumors were flow sorted to exclude non-tumor DNA and increase our ability to detect gene copy number changes. In these tumors, losses were more frequent than gains, and gains in 1q and loss in 16q were the most frequent alterations. We compared gene copy number changes in the tumors based on histologic subtype and estrogen receptor (ER) status, i.e., ER-negative infiltrating ductal carcinoma, ER-positive infiltrating ductal carcinoma, and ER-positive infiltrating lobular carcinoma. We observed a consistent association between loss in regions of 5q and ER-negative infiltrating ductal carcinoma, as well as more frequent loss in 4p16, 8p23, 8p21, 10q25, and 17p11.2 in ER-negative infiltrating ductal carcinoma compared with ER-positive infiltrating ductal carcinoma (adjusted P values < or = 0.05). We also observed high-level amplifications in ER-negative infiltrating ductal carcinoma in regions of 8q24 and 17q12 encompassing the c-myc and c-erbB-2 genes and apparent homozygous deletions in 3p21, 5q33, 8p23, 8p21, 9q34, 16q24, and 19q13. ER-positive infiltrating ductal carcinoma showed a higher frequency of gain in 16p13 and loss in 16q21 than ER-negative infiltrating ductal carcinoma. Correlation analysis highlighted regions of change commonly seen together in ER-negative infiltrating ductal carcinoma. ER-positive infiltrating lobular carcinoma differed from ER-positive infiltrating ductal carcinoma in the frequency of gain in 1q and loss in 11q and showed high-level amplifications in 1q32, 8p23, 11q13, and 11q14. These results indicate that array comparative genomic hybridization can identify significant differences in the genomic alterations between subtypes of breast cancer.

Odorant receptor expressed sequence tags demonstrate olfactory expression of over 400 genes, extensive alternate splicing and unequal expression levels

BACKGROUND

The olfactory receptor gene family is one of the largest in the mammalian genome. Previous computational analyses have identified approximately 1,500 mouse olfactory receptors, but experimental evidence confirming olfactory function is available for very few olfactory receptors. We therefore screened a mouse olfactory epithelium cDNA library to obtain olfactory receptor expressed sequence tags, providing evidence of olfactory function for many additional olfactory receptors, as well as identifying gene structure and putative promoter regions.

RESULTS

We identified more than 1,200 odorant receptor cDNAs representing more than 400 genes. Using real-time PCR to confirm expression level differences suggested by our screen, we find that transcript levels in the olfactory epithelium can differ between olfactory receptors by up to 300-fold. Differences for one gene pair are apparently due to both unequal numbers of expressing cells and unequal transcript levels per expressing cell. At least two-thirds of olfactory receptors exhibit multiple transcriptional variants, with alternative isoforms of both 5' and 3' untranslated regions. Some transcripts (5%) utilize splice sites within the coding region, contrary to the stereotyped olfactory receptor gene structure. Most atypical transcripts encode nonfunctional olfactory receptors, but can occasionally increase receptor diversity.

CONCLUSIONS

Our cDNA collection confirms olfactory function of over one-third of the intact mouse olfactory receptors. Most of these genes were previously annotated as olfactory receptors based solely on sequence similarity. Our finding that different olfactory receptors have different expression levels is intriguing given the one-neuron, one-gene expression regime of olfactory receptors. We provide 5' untranslated region sequences and candidate promoter regions for more than 300 olfactory receptors, valuable resources for computational regulatory motif searches and for designing olfactory receptor microarrays and other experimental probes.

Different evolutionary processes shaped the mouse and human olfactory receptor gene families

We report a comprehensive comparative analysis of human and mouse olfactory receptor (OR) genes. The OR family is the largest mammalian gene family known. We identify approximately 93% of an estimated 1500 mouse ORs, exceeding previous estimates and the number of human ORs by 50%. Only 20% are pseudogenes, giving a functional OR repertoire in mice that is three times larger than that of human. The proteins encoded by intact human ORs are less highly conserved than those of mouse, in patterns that suggest that even some apparently intact human OR genes may encode non-functional proteins. Mouse ORs are clustered in 46 genomic locations, compared to a much more dispersed pattern in human. We find orthologous clusters at syntenic human locations for most mouse genes, indicating that most OR gene clusters predate primate-rodent divergence. However, many recent local OR duplications in both genomes obscure one-to-one orthologous relationships, thereby complicating cross-species inferences about OR-ligand interactions. Local duplications are the major force shaping the gene family. Recent interchromosomal duplications of ORs have also occurred, but much more frequently in human than in mouse. In addition to clarifying the evolutionary forces shaping this gene family, our study provides the basis for functional studies of the transcriptional regulation and ligand-binding capabilities of the OR gene family.

Bloodborne sexually transmitted infections in patients presenting for substance abuse treatment in Jamaica

BACKGROUND

Substance use, including alcohol and illicit drugs, increases the risk for the acquisition and transmission of sexually transmitted infection (STI).

GOAL

To determine the prevalence of bloodborne STI including HIV, human T-cell lymphotrophic virus type 1, hepatitis B virus, and syphilis in residents of a detoxification and rehabilitation unit in Jamaica.

STUDY DESIGN

The demographic characteristics and the results of laboratory investigations for STI in 301 substance abusers presenting during a 5-year period were reviewed. The laboratory results were compared with those of 131 blood donors.

RESULTS

The substances used by participants were alcohol, cannabis, and cocaine. None of the clients was an IV drug user. Female substance abusers were at higher risk for STI. The prevalence of STI in substance abusers did not differ significantly from that in blood donors (12% versus 10%); however, the prevalence of syphilis in substance abusers was significantly higher than that in blood donors (6% versus 3%, P < 0.05). The prevalence of syphilis was dramatically increased in female substance abusers and female blood donors (30%, P < 0.001 and 13%, P < 0.05, respectively). An excess of human T-cell lymphotrophic virus type 1 was also observed in female compared with male substance abusers. Unemployment was identified also as a risk factor for sexually transmitted disease in substance abusers.

CONCLUSION

The results endorsed the policy of screening detoxification clients for STI and indicate a need for gender-specific approaches to the control of substance abuse and STI in Jamaica.

Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls

Modern members of the mammalian order Cetacea (whales, dolphins and porpoises) are obligate aquatic swimmers that are highly distinctive in morphology, lacking hair and hind limbs, and having flippers, flukes, and a streamlined body. Eocene fossils document much of cetaceans' land-to-water transition, but, until now, the most primitive representative for which a skeleton was known was clearly amphibious and lived in coastal environments. Here we report on the skeletons of two early Eocene pakicetid cetaceans, the fox-sized Ichthyolestes pinfoldi, and the wolf-sized Pakicetus attocki. Their skeletons also elucidate the relationships of cetaceans to other mammals. Morphological cladistic analyses have shown cetaceans to be most closely related to one or more mesonychians, a group of extinct, archaic ungulates, but molecular analyses have indicated that they are the sister group to hippopotamids. Our cladistic analysis indicates that cetaceans are more closely related to artiodactyls than to any mesonychian. Cetaceans are not the sister group to (any) mesonychians, nor to hippopotamids. Our analysis stops short of identifying any particular artiodactyl family as the cetacean sister group and supports monophyly of artiodactyls.

Antibodies to hepatitis B virus and hepatitis C virus in residential detoxification clients in Jamaica

The role of non-injecting drug abuse in viral hepatitis has not been studied widely and is not well understood. A total of 301 substance abusers, residents of a detoxification/rehabilitation unit, were investigated for exposure to hepatitis B virus (HBV) and hepatitis C virus (HCV). Samples of serum were tested for anti-HCV and anti-HBc antibodies and HBsAg. All of the patients were non-injecting drug users (non-IDUs). The prevalence of anti-HCV was 1.7%; anti-HBc was found in 28.7% and HbsAg in 0.6% of patients. Anti-HCV positivity correlated with the presence of elevated aminotransferases (80%). Exposure to HBV correlated significantly with gender (p < 0.05); age (p < 0.05); and duration of substance abuse (p < 0.05). No significant correlations were found between HCV and/or HBV infection, the drug of abuse, HIV, HTLV-1 or syphilitic infection. Residential detoxification/rehabilitation provides an opportune moment to identify and treat HCV positive substance abusers in the attempt to avert the severe hepatic sequelae. Measures which exclude substance abusers from volunteer blood donation should be considered.

Understanding variations in survival for colorectal cancer in Europe: a EUROCARE high resolution study

BACKGROUND

Marked differences in population based survival across Europe were found for colorectal cancers diagnosed in 1985-1989.

AIMS

To understand the reasons for these differences in survival in a new analysis of colorectal cancers diagnosed between 1988 and 1991.

SUBJECTS

A total of 2720 patients with adenocarcinoma of the large bowel from 11 European cancer registries (CRs).

METHODS

We obtained information on stage at diagnosis, diagnostic determinants, and surgical treatment (not routinely collected by CRs) and analysed the data in relation to three year observed survival, calculating relative risks (RRs) of death and adjusting for age, sex, site, stage, and determinants of stage.

RESULTS

Three year observed survival rates ranged from 25% (Cracow) to 59% (Modena), and were low in the Thames area (UK) (38%). Survival rates between registries for "resected" patients varied less than those for all patients. When age, sex, and site were considered, RRs ranged from 0.7 (95% confidence intervals (CI) 0.6-0.9) (Modena) to 2.3 (95% CI 1.9-2.9) (Cracow). After further adjustment by stage, between registry RR variation was between 0.8 (95% CI 0.6-0.9) and 1.8 (95% CI 1.5-2.2). Inter-registry RR differences were slightly reduced when the determinants of stage (number of nodes examined and liver imaging) were included in the model. The reduction was marked for the UK registries.

CONCLUSIONS

The wide differences across Europe in colorectal cancer survival depend to a large extent on differences in stage at diagnosis. There are wide variations in diagnostic and surgical practices. There was a twofold range in the risk of death from colorectal cancer even after adjustment for surgery and disease stage.

Within-breath arterial PO2 oscillations in an experimental model of acute respiratory distress syndrome

Tidal ventilation causes within-breath oscillations in alveolar oxygen concentration, with an amplitude which depends on the prevailing ventilator settings. These alveolar oxygen oscillations are transmitted to arterial oxygen tension, PaO2, but with an amplitude which now depends upon the magnitude of venous admixture or true shunt, QS/QT. We investigated the effect of positive end-expiratory pressure (PEEP) on the amplitude of the PaO2 oscillations, using an atelectasis model of shunt. Blood PaO2 was measured on-line with an intravascular PaO2 sensor, which had a 2-4 s response time (10-90%). The magnitude of the time-varying PaO2 oscillation was titrated against applied PEEP while tidal volume, respiratory rate and inspired oxygen concentration were kept constant. The amplitude of the PaO2 oscillation, delta PaO2, and the mean PaO2 value varied with the level of PEEP applied. At zero PEEP, both the amplitude and the mean were at their lowest values. As PEEP was increased to 1.5 kPa, both delta PaO2 and the mean PaO2 increased to a maximum. Thereafter, the mean PaO2 increased but delta PaO2 decreased. Clear oscillations of PaO2 were seen even at the lowest mean PaO2, 9.5 kPa. Conventional respiratory models of venous admixture predict that these PaO2 oscillations will be reduced by the steep part of the oxyhaemoglobin dissociation curve if a constant pulmonary shunt exists throughout the whole respiratory cycle. The facts that the PaO2 oscillations occurred at all mean PaO2 values and that their amplitude increased with increasing PEEP suggest that QS/QT, in the atelectasis model, varies between end-expiration and end-inspiration, having a much lower value during inspiration than during expiration.

Expiratory airflow patterns in children and adults with cystic fibrosis

STUDY OBJECTIVE

To determine whether tidal expiratory airflow patterns change with increasing airways obstruction in patients with cystic fibrosis.

DESIGN

An observational study.

SETTING

Lung function laboratory.

PATIENTS

Sixty-four children and young adults with cystic fibrosis.

MEASUREMENTS

After measuring FEV(1) and airways resistance using body plethysmography, each subject was seated and asked to mouth breathe through a pneumotachograph for 2 min. The collected data were analyzed, and three expiratory airflow pattern-sensitive indexes were computed. The first index was derived from the ratio of the time to reach peak expiratory flow to the total expiratory time (tPTEF/tE). The second index, Trs, was an estimate of the time constant of the passive portion of expiration. The third index, f1.gif" BORDER="0">, describes the slope of the whole post-peak expiratory flow pattern after scaling.

RESULTS

Compared with FEV(1), the index tPTEF/tE was a poor indicator of airways obstruction (r(2) = 0.15, p = 0.002). Trs showed a strong relationship with the severity of airways obstruction (r(2) = 0.46, p < 0.001). Using f1.gif" BORDER="0">, the postexpiratory profile could be categorized into three shapes, and provided a good indicator of airways obstruction when linear and concave-shaped profiles occurred (r(2) = 0.42, p < 0.001). Convex-shaped flow profiles had to be treated separately and were indicative of normal lung function.

CONCLUSIONS

In a cross-sectional study of patients with cystic fibrosis, increase in airways resistance above normal is reflected by quantifiable changes in the expiratory airflow pattern.

An IBM PC-based system for the assessment of cardio-respiratory function using oscillating inert gas forcing signals

OBJECTIVE

An IBM PC-based real-time data acquisition, monitoring and analysis system was developed for the assessment of cardio-respiratory function, i.e. airway dead space, alveolar volume and pulmonary blood flow, using oscillating inert inspired gas forcing signals.

METHODS

The forcing gas mixture was generated by an in-house sinusoid gas delivery unit. The system interfaced with a mass spectrometer and an airway flow transducer, and performed real-time tracking of the breath-by-breath end-inspired, end-expired and mixed-expired concentrations. It calculated the cardiorespiratory parameters using two, i.e. continuous and tidal, in-house mathematical models of the lungs. The system's performance was evaluated using a mechanical bench lung, laboratory subjects and awake adults breathing spontaneously. Its predictive accuracy was compared with the measured volumes of the bench lung; single breath CO2 test for airway dead space and N2 washout for alveolar volume in laboratory subjects and awake adults; and thermal dilution technique for pulmonary blood flow in laboratory subjects.

RESULTS

Close agreements were found between the true and predicted airway dead space, i.e. mean differences of -12.39%, 14.47% and -17.49%, respectively, and that of alveolar volume, i.e. -8.03%, -3.62% and 7.22%, respectively, in the bench lung, laboratory subject and awake adult studies; and that of pulmonary blood flow (-23.81%) in the laboratory subjects using the continuous lung model. Even closer agreements were observed for airway dead space (-5.8%) and alveolar volume (-4.01%) of the bench lung and for pulmonary blood flow (-8.47%) in the laboratory subjects using the tidal lung model.

CONCLUSIONS

A system was developed to deliver, monitor and analyse on-line, and in real-time, output data from the sinusoid forcing technique. The technique was administered using the system in various subjects, and produced favourable predictions.

What lessons can be learned for cancer registration quality assurance from data users? Skin cancer as an example

BACKGROUND

In cancer registration, data cleaning (i.e. amendments made by data users to datasets released by registries) is potentially informative for quality assurance, but generally underreported.

AIM

To assess the scope for learning lessons about cancer registration quality assurance from a data user (using skin cancer as the example).

METHODS

The main design features were: (i) A descriptive study identifying, qualitatively and quantitatively, the breadth, depth, and impact of quality assurance issues raised by a user cleaning Merseyside and Cheshire Cancer Registry skin cancer data. Errors were rectified and pitfalls for interpretation were identified. (ii) A nested validation of morphology and site coding on random samples of cutaneous malignant melanomas, basal cell carcinomas (BCC), and squamous cell carcinomas. The 33132-record dataset comprised: all registered skin lesions, except metastases; most recorded variables (about patient, lesion, treatment, outcome); for Merseyside and Cheshire residents diagnosed 1970-1991.

RESULTS

(i) Ineligible cases represented 0.3% (97/33132), and were detected best by morphology checks. Most quality assurance issues identified related to local custom and practice, staff training, and computerization, being particularly illustrated by problematic BCC registration practice (e.g. records written over unchallenged by range checks; and idiosyncratic use of variables). (ii) Post-cleaning, morphology coding errors were minimal in the random samples.

CONCLUSION

There is great scope for data users to contribute to cancer registration quality assurance. Ultimately, the study dataset appeared fit for epidemiological analysis and important quality assurance messages emerged. Shared explicit standard guidelines for data preparation and validation are needed by users, whose insights could and should be better recognized by cancer registries.

The significance of immune disorder in tropical spastic paraparesis

The reports of the occurrence of HTLV-1 infection and/or HTLV-1 associated myelopathy (HAM/tropical spastic paraparesis (TSP) in patients with certain organ-specific and nonorgan-specific autoimmune diseases prompted us to assess the relationship between TSP and humoral autoimmunity. Blood samples from 76 TSP patients, 60 asymptomatic HTLV-1 carriers and 100 HTLV-1 seronegative blood donors were examined for the presence of organ-specific and nonorgan-specific autoantibodies, reactive serological tests for syphilis, immunoglobulin and complement concentrations as well as immunecomplexes. High prevalences of autoantibodies (39/76, 51%), reactive serological tests for syphilis (23/76; 30%), hypergammaglobulinaemia (69/76, 90%) and complement fixing immune complexes (44/76, 58%) were found in the TSP patients. These indicators of immunological disorder were found in statistically significantly lower prevalences in asymptomatic HTLV-1 carriers (12/60, 20%; p < 0.001; 6/60, 10%; p < 0.05; 32/60, 53%; p < 0.001 and 8/60, 13%; p < 0.001, respectively) and HTLV-1 seronegative blood donors (8/100, 8%; p < 0.001; 3/100, 3%; p < 0.001; 15/100, 15%; p < 0.001 and 5/100, 5%; p < 0.001, respectively). The profiles of autoimmune phenomena observed in the patient and control groups revealed that they were associated with TSP rather than mere HTLV-1 infection and consequently pathogenetic significance. The array of immunological features present in TSP was suggestive of autoimmune disease resulting from immune dysfunction. Studies which explore the possible existence of HTLV-1 induced autoantibodies with specificity for antigens of the spinal cord in TSP might be useful in elucidating its pathogenesis.

New classification of oesophageal and gastric carcinomas derived from changing patterns in epidemiology

The current ICD-O classification of carcinomas of the oesophagus and stomach causes epidemiological and clinical confusion. This study compares the epidemiological and clinical features of each subtype and subsite of adenocarcinomas of the oesophagus and stomach, to assess requirements for a new classification of these carcinomas. Data were extracted with appropriate validity checks on all cases of oesophageal and gastric carcinomas identified throughout the period 1974-1993 by the Merseyside and Cheshire Cancer Registry, which covers a population of 2.5 million. The incidence of adenocarcinomas of the lower oesophagus and cardia trebled in males, and doubled in females, whereas adenocarcinoma of the subcardia region of the stomach declined in both sexes. Adenocarcinomas of the lower oesophagus and of the cardia were similar for median age at diagnosis, male to female ratio, percentage of patients who smoked and survival; both were significantly different from carcinomas of the subcardia in these respects. These data imply that adenocarcinomas of the lower oesophagus and cardia are the same disease. A new subsite classification of oesophageal and gastric carcinomas is proposed that includes the gastro-oesophageal junction as a distinct subsite, to facilitate surveillance, management and research.

Tidal expired airflow patterns in adults with airway obstruction

Earlier studies have shown that time and flow indices derived from tidal expiratory flow patterns can be used to distinguish the severity of airway obstruction. This study was designed to address two aspects of tidal expiratory flow patterns: 1) how do expiratory flow patterns differ between subjects with normal and obstructed airways; and 2) can a sensitive index of airway obstruction be derived from these pattern differences? Tidal expiratory flow patterns from 66 adult subjects with varying degrees of airway obstructive disease with a forced expiratory volume in one second (FEV1) of 20-121% predicted were examined. In each subject, the expired flow pattern from each consecutive breath was scaled and then averaged together to create a single expired pattern. A detailed examination of the scaled flow patterns in 12 subjects (six with normal airways and six with airway obstruction) showed that the shape of the post-peak expiratory flow portion was different in the subjects with airway obstruction. A slope index, S, was derived from the scaled patterns and found to be sensitive to the severity of airway obstruction, correlating with FEV1 (% pred) with r2=0.74 (p<0.05, n=57). The S index also correlated (r2=0.36, p<0.05, n=47) with the functional residual capacity (FRC) (% pred) which was >100% in subjects with severe airway obstruction and lung overinflation. In subjects with normal airways, three further airflow patterns could be distinguished, which were different from the patterns seen in subjects with the severest airway obstruction. Scaled flow patterns from tidal expiration collected from uncoached subjects, can be used to derive an index of airway obstruction.

Pulmonary blood flow measured by inspiratory inert gas concentration forcing oscillations

The aim of this study was to discover if the forced inspired inert gas sinewave technique could be used to measure pulmonary blood flow, using nitrous oxide as the indicator gas, following inotropic stimulation of the heart by dobutamine, in the presence of a constant alveolar ventilation. Cardiac output (range 1-4.5 L min(-1)) was measured in six dogs by thermodilution and by calculation from the sinusoidal expired partial pressures of argon and nitrous oxide using: (i) analytical equations and a conventional continuous ventilation three-compartment lung model, which did not include recirculation; and (ii) a digital simulation tidal ventilation lung model (Gavaghan and Hahn, 1996. Respir. Physiol. 106, 209-221) which was adapted to include nitrous oxide mixed-venous recirculation from a combined single viscera compartment. The continuous ventilation model calculations always underestimated thermodilution cardiac output, with the bias error increasing to almost -1 L min(-1) at the longest forcing periods, 4-5 min. In contrast, the tidal ventilation model calculations were in close agreement to thermodilution cardiac output, with biases of -0.04 and -0.26 L min(-1) at forcing periods of 2 and 3 min, respectively.

Mucosal melanoma of the head and neck

Two hundred and fifty-nine patients with mucosal melanoma of the head and neck were reviewed. The data of these patients were obtained from the records of the Department of Head and Neck Oncology at the University of Liverpool and from the Merseyside and Cheshire Cancer Registry. Survival curves were constructed using the life table method and differences were investigated by the Log Rank Test. Prognostic factors were further analysed by Cox's proportional hazards model. Melanomas of the nasal cavities and sinuses accounted for 69%; 22% occurred in the oral cavity and 9% in the pharynx, larynx and upper oesophagus. In 49% treatment was by wide local resection and in 8% by irradiation. Thirty-six per cent had combined modalities of treatment. Primary site recurrence occurred in 52% and 36% developed nodal recurrence. The tumour specific survival at 5 years was 45% at 10 years 28%, at 20 years 17% and closely resembled the observed survival. Young male patients tended to have a favourable prognosis as did those treated surgically. Radiotherapy on its own was ineffective. Amelanotic melanoma had a particularly poor survival. Whereas site had no effect on survival. The study confirms the poor prognosis of mucosal melanoma of the head and neck. Young patients should be offered radical surgical treatment combined with radical radiotherapy if feasible as this offers the best chance of cure.

Alveolar and dead space volume measured by oscillations of inspired oxygen in awake adults

Forced sinusoidal oscillations in the inspired concentration of a low-solubility inert gas can be used to measure airways dead space and alveolar volume. When inspired oxygen is oscillated about its mean value in the same way, the ratio between the amplitudes of the resulting end-expired and inspired oxygen oscillations is the same as that of an inert gas such as argon. Thus, oxygen forcing oscillations can be used to measure lung volume. In nine healthy spontaneously breathing adults, the FIO2 (mean FIO2 = 0.26, mean minute volume = 8.5 L/min) was forced to sinusoidally oscillate with an amplitude of +/- 0.04. The mean airways dead space measured using FIO2 oscillations with a forcing period of 3 min was 0.17 +/- 0.04 L, and the airways dead space measured by a single-breath C02 technique was no different at 0.19 +/- 0.03 L. An oxygen oscillation of the same period measured the mean end-expired alveolar volume at 3.1 +/- 0.7 L. Adding together the airways dead space and end-expired alveolar volume, obtained by the oxygen oscillation technique, provided a measure of FRC that at 3.3 +/- 0.7 L matched the FRC of 3.3 +/- 0.8 L measured by whole-body plethysmography. A third measure of FRC using a multiple-breath nitrogen washout technique gave a smaller volume of 3.00 +/- 0.85 L. The advantage of using FIO2 oscillations is that accurate FRC measurements can be made continuously, without interfering with the subject's natural breathing rhythm.

A reconciliation of continuous and tidal ventilation gas exchange models

Continuous-ventilation mathematical gas exchange models are widely used since their analytical equations are amenable to physiological interpretation. They describe qualitatively the respiratory system's response to changing physiological conditions, but do not calculate accurate values for respiratory parameters when experimental tidal ventilation expired gas data are inserted into their analytical expressions. A simple mathematical expression is presented to reconcile continuous and tidal ventilation gas exchange models. Tidal ventilation experimental data can then be inserted into conventional continuous ventilation equations to produce more accurate measures of lung volume. This hypothesis is tested with controlled experimental tidal ventilation tracer gas data obtained from both wash-out and forced inspired sinusoid experiments, using a mechanical lung model with known volume; tidal volume, VT; and series 'airway' dead space VD. We show that the subtraction of 1/2 (VT + VD) from the lung volume calculated from the continuous ventilation theory can produce lung volume measurements which agree with the true lung volume to within +/-5%, for physiological lung volume values, for both wash-out and forced sinusoid techniques.

Oxygen transport with oscillations of inspired oxygen concentration

A theoretical model predicts that forced inspiratory oxygen concentration oscillations can be used to recover cardiorespiratory data and elicit information about the oxygen transport system (Hahn, 1996). The effects of hypoxia on the penetration of these generated oxygen oscillations into arterial and venous blood were explored in dogs exposed to a graded severity of hypoxia. Continuously recorded sinusoidal oxygen oscillations in the respired partial pressure, blood tension and mixed-venous saturation show that the transmission of forced oxygen oscillations from the lungs to the arterial blood depends on the mean arterial saturation. When mean inspired oxygen is high enough to fully saturate arterial haemoglobin, an inspired oscillation can only be transmitted in the blood as an oscillation in oxygen tension. However, in the presence of arterial hypoxaemia, oscillations in both the oxygen saturation and partial pressure of arterial blood are observed. Under these conditions, the oxygen saturation and partial pressure oscillations are also transmitted to mixed-venous blood. Our data illustrates that the link between the arterial and mixed-venous oscillations is non-linear and dependent on the sigmoidal binding relationship between oxygen and haemoglobin.

Data quality in population-based cancer registration: an assessment of the Merseyside and Cheshire Cancer Registry

Merseyside and Cheshire Cancer Registry (MCCR) data quality was assessed by applying literature-based measures to 27,942 cases diagnosed in 1990 and 1991. Registrations after death (n = 8535) were also audited (n = 917) to estimate death certificate only (DCO) case accuracy and the proportion of registrations notified by death certificate (DC). Ascertainment appeared to be high from the registration/mortality ratio for lung [1.01:1] and to be low from capture-recapture estimates (59.4%), varying significantly with site from oesophagus [92.2% (95% CI 88.5-95.9)] to breast [47.5 (95% CI 41.8-53.2)]. The estimated DC-dependent proportion was 20% (5601 out of 27 942) with successful traceback in 3533 out of 5601 (63.1%) cases. DCO flagging (2497 out of 27,942, 8.9%) overestimated true DCO cases (2068 out of 27,942, 7.4%). The proportion of cases of unknown primary site was low (1.5%), varying significantly with age [0-4.2%, (95% CI 2.5-5.9)] and district [0.8% (95% CI 0.3-1.3) to 2.2% (95% CI 1.8-2.6)]. The median diagnosis to registration interval appeared to be good (10 weeks), varying significantly with site (P < 0.0001), age (P < 0.0001) and district (P < 0.0001). The proportion with a verified diagnosis was 77.3%, varying significantly with site [lung 55.2% (95% CI 53.7-56.7) to cervix 96.9% (95% CI 96.3-97.5)], age [45.2% (95% CI 40.9-49.5) to 97.5% (95% CI 96.4-98.6)] and district [71.8% (95% CI 69.9-73.8) to 82.5% (95% CI 80.7-84.3)]. The DCO percentages varied similarly by site [non-melanoma skin 0.4% (95% CI 0.2-0.6) to lung 22.6% CI (95% 19.9-25.3)], age [0.7(95% CI 0.1-1.4) to 23.0 (95% CI 19.4-26.6)] and district [6.9% (95% CI 5.7-8.1) to 13.9% (95% CI 12.9-15.0)]. MCCR data quality varied with age, site and district - inviting action - and apparently compares favourably with elsewhere, although deficiencies in published data hampered definitive assessment. Putting quality assurance into practice identified shortcomings in the scope, definition and application of existing measures, and absent standards impeded interpretation. Cancer registry quality assurance should henceforward be within an explicit framework of agreed and standardized measures.

Prenatal administration of buprenorphine in the rat: effects on the rest-activity cycle at 22 and 30 days of age

Three doses of buprenorphine (BUP) were administered by osmotic minipump from day 8 of gestation through parturition. In addition to 0.3, 1.0, and 3.0 mg/kg/day of BUP, a vehicle control group received sterile water via minipump and a nontreated control group was left undisturbed during pregnancy. All treated and control litters were fostered at birth to untreated dams. BUP produced a dose response reduction in maternal water intake and reduced maternal weight gain among the two high dose groups; resorptions and birthweight were unaffected. BUP increased perinatal mortality in the two high dose groups compared with the vehicle controls and produced inconsistent effects on postnatal growth. To examine the effects of BUP on the rest-activity cycle of the offspring, groups of 3 littermates from each of the treated and control groups were tested for an 8 h observation period on electronic activity monitors at 22 and 30 days of age. Unlike previous effects described for prenatally administered methadone, a disruption in the rest-activity cycle was not observed for any of the BUP treated groups.

Measurement of respiratory parameters by using inspired oxygen sinusoidal forcing signals

A companion paper (C. E. W. Hahn. J. Appl. Physiol 81: 985-997, 1996) described a continuous-flow gas-exchange mathematical model, which predicted that forced inspired oxygen sinusoids could be used to measure respiratory parameters rapidly, in place of the inert gas argon. We therefore made simultaneous measurements of dead space volume (VD) and alveolar volume (VA) in an animal model, using argon and oxygen inspired gas concentration sinusoid forcing signals, and then compared the results. Our data confirmed the model prediction that the attenuations of the oxygen and argon sinusoid perturbations are identical in the alveolar gas space, even though there is a net uptake of oxygen by the body. Our results show that the calculated values of VD and VA, obtained by using inspired oxygen forcing signals, were independent of both the mean fractional inspired oxygen concentration (FIO2; range 0.18-0.80% vol/vol) and the oxygen forcing signal amplitude (range +/- 2-6% vol/vol). In these studies, oxygen forcing signals, with forcing periods between 1 and 2 min, were able to measure controlled changes in instrument dead space to within 16 ml and also measure positive end-expiratory pressure-induced changes in VA. Under hyperoxic conditions, intravascular oxygen sensors confirmed that the sinusoidal PO2 signal passed into the arterial blood but not into the mixed-venous blood. However, the sinusoid perturbation PO2 signal did pass into the mixed-venous blood when the mean FIO2 was mildly hypoxic (FIO2 = 0.18% vol/vol). These data show that oxygen can be used instead of argon to measure airways dead space and VA.

"Inaccuracy' in death certification--where are we now?

BACKGROUND

This review aims to document and analyse aspects of death certification that are relevant to public health.

METHODS

A literature review on death certification primarily used the computerized Index Medicus (1981 to mid-1995), and concentrated on completing death certificates, accuracy, standards, education and procedural requirements. Further sentinel publications pre-dating this were identified from the main literature base.

RESULTS

The uses of mortality data, historical and procedural context for recording death, the philosophy of Underlying Cause of Death and its relationship to the truth, the extent and impact of "inaccuracy', the certificate and the certifier, and possible ways forward are discussed. It is argued that the question "How inaccurate are cause of death data?' is harder to answer than the literature suggests. Deriving a useful estimate is difficult because of inter-study differences in (1) definition, measurement (how and by whom?) and practical importance of error, and standards used; (2) focus (e.g. death certificate or mortality data), observing everyday practice or simulation exercises, diagnostic and/or semantic issues.

CONCLUSION

The traditional perspective on improving the quality of death certification has not worked. There is a need for reorientated thinking rather than just urging more education. Evidence-based educational interventions are needed. The flaws in the theoretical framework of cause of death and the routine nature of death certification are unavoidable, but require consideration. Certifiers need practical feedback mechanisms, integral to continuing quality assurance at all levels and fostering an understanding of the construction of mortality data. Continued development should be a core public health medicine role.

Asthma deaths in Mersey region 1989-1990

BACKGROUND

We examined the circumstances surrounding death from asthma in Mersey Region and the feasibility of conducting a regional confidential enquiry, as suggested by the British Thoracic Society in response to the proposal in the Green Paper the health of the nation that asthma should be a key area for action.

METHOD

Sixty-three Mersey residents, aged 16-65 years, died in Mersey Region in 1989 and 1990 with ICD code 493. Diagnostic criteria for asthma were applied to each case. Anonymized case-note summaries were assessed by a chest physician (M.P.) for (1) severity of symptoms/disease, (2) risk of a respiratory death and (3)avoidable factors in the circumstances surrounding death.

RESULTS

Some written information was available on every patients. In 43/63 (68 percent) cases asthma was the true cause of death; 41/43 had had asthma diagnosed in life. Mean age (47 years) and median age of onset of asthma (10 years) were similar to those found in previous studies, but the proportion of men (58 percent) was higher. Only 6 (14 percent) deaths occurred after more than a few hours in hospital; for the rest, hospital contact was either too late (19 percent) or did not occur (67 percent). Of 22/43 (51 percent) patients considered at high risk of a respiratory death, 15 had poorly controlled symptoms for at least a year before their deaths. Avoidable factors were present in 29/43 (67 percent) cases; most commonly lack of assessment, inadequate doses of steroids and over-reliance on bronchodilators.

CONCLUSION

These findings resemble those of previous studies, showing that little has changed. Asthma deaths occur mostly outside hospital; thus to replace deaths, resources should be directed at the community to improve the recognition of asthma by patients, their families and the primary care team. A regional confidential enquiry is feasible and could be an effective mechanism for proving management.

Measurement of tidal flow using a transit-time ultrasonic breath analyser

The ability of the Transit-time Ultrasonic Breath Analyser (TUBA, GHG Medical Electronics GMBH, Zürich, Switzerland) to measure peak flow and tidal volume in the laboratory was tested using a variety of flow and pressure conditions, chosen to simulate the respiratory patterns of patients receiving mechanical ventilatory support. A stable zero baseline was achieved by acoustic damping of the TUBA flow sensor head. A piston pump was used to generate sinusoidal flow pattern, with a peak flow range from 0.1 to 1.51.s-1. The calculated peak flow matched the peak flow measured by the TUBA. The TUBA accurately measured tidal volumes (+/- 10%) delivered using three different flow patterns over a range of volumes from 0.25 to 11. We conclude, that once modified, the TUBA can provide an accurate measurement of peak flow and tidal volume over a range of values likely to be encountered during mechanical ventilation of the lungs.

Neuroendoscopic laser-assisted ventriculostomy of the third ventricle

Hydrocephalus is caused by an imbalance between the production and absorption of cerebrospinal fluid. Ventriculostomy of the third ventricle now is an acceptable treatment alternative for this problem. This procedure reduces costs over the course of the illness because the patient does not require subsequent shunt revisions throughout his or her life. The specialized care and the fear associated with the dependency on mechanical hardware also are eliminated if shunt placement is avoided. Postoperative complications may include increased intracranial pressure, bleeding, infection, and pain.

A regional survey of intravenous therapy practices

In this article, the authors share the results of a survey developed by a group of nurses in a 400-bed community hospital and distributed to 25 health care agencies throughout the northeastern New York region. The survey is comprised of six major categories, with questions pertaining to flushing and dressing protocols, types of vascular access devices used, and the availability of equipment and resources. Sixty percent of the agencies responded, including hospital, home care, hospice, and physician office settings. Major findings identified a lack of consistency in flushing and dressing protocols and in the types of equipment used. Implications for future practice will be presented along with the results of the survey.

Assessment of cardiorespiratory function using oscillating inert gas forcing signals

A theoretical model (Hahn et al. J. Appl. Physiol. 75: 1863-1876, 1993) predicts that the amplitudes of the argon and nitrous oxide inspired, end-expired, and mixed expired sinusoids at forcing periods in the range of 2-3 min (frequency 0.3-0.5 min-1) can be used directly to measure airway dead space, lung alveolar volume, and pulmonary blood flow. We tested the ability of this procedure to measure these parameters continuously by feeding monosinusoidal argon and nitrous oxide forcing signals (6 +/- 4% vol/vol) into the inspired airstream of nine anesthetized ventilated dogs. Close agreement was found between single-breath and sinusoid airway dead space measurements (mean difference 15 +/- 6%, 95% confidence limit), N2 washout and sinusoid alveolar volume (mean difference 4 +/- 6%, 95% confidence limit), and thermal dilution and sinusoid pulmonary blood flow (mean difference 12 +/- 11%, 95% confidence limit). The application of 1 kPa positive end-expiratory pressure increased airway dead space by 12% and alveolar volume from 0.8 to 1.1 liters but did not alter pulmonary blood flow, as measured by both the sinusoid and comparator techniques. Our findings show that the noninvasive sinusoid technique can be used to measure cardiorespiratory lung function and allows changes in function to be resolved in 2 min.

Self-esteem, social support, and satisfaction differences in women with adequate and inadequate prenatal care

This descriptive, retrospective study examined levels of self-esteem, social support, and satisfaction with prenatal care in 193 low-risk postpartal women who obtained adequate and inadequate care. The participants were drawn from a regional medical center and university teaching hospital in New Mexico. A demographic questionnaire, the Coopersmith self-esteem inventory, the personal resource questionnaire part 2, and the prenatal care satisfaction inventory were used for data collection. Significant differences were found in the level of education, income, insurance, and ethnicity between women who received adequate prenatal care and those who received inadequate care. Women who were likely to seek either adequate or inadequate prenatal care were those whose total family income was $10,000 to $19,999 per year and high school graduates. Statistically significant differences were found in self-esteem, social support, and satisfaction between the two groups of women. Strategies to enhance self-esteem and social support have to be developed to reach women at risk for receiving inadequate prenatal care.