A two centre observational study of simultaneous pulse oximetry and arterial oxygen saturation recordings in intensive care unit patients.

The influence of variables that might affect the accuracy of pulse oximetry (SpO2) recordings in critically ill patients is not well established. We sought to describe the relationship between paired SpO2/SaO2 (oxygen saturation via arterial blood gas analysis) in adult intensive care unit (ICU) patients and to describe the diagnostic performance of SpO2 in detecting low SaO2 and PaO2. A paired SpO2/SaO2 measurement was obtained from 404 adults in ICU. Measurements were used to calculate bias, precision, and limits of agreement. Associations between bias and variables including vasopressor and inotrope use, capillary refill time, hand temperature, pulse pressure, body temperature, oximeter model, and skin colour were estimated. There was no overall statistically significant bias in paired SpO2/SaO2 measurements; observed limits of agreement were +/-4.4%. However, body temperature, oximeter model, and skin colour, were statistically significantly associated with the degree of bias. SpO2 <89% had a sensitivity of 3/7 (42.9%; 95% confidence intervals, CI, 9.9% to 81.6%) and a specificity of 344/384 (89.6%; 95% CI 86.1% to 92.5%) for detecting SaO2 <89%. The absence of statistically significant bias in paired SpO2/SaO2 in adult ICU patients provides support for the use of pulse oximetry to titrate oxygen therapy. However, SpO2 recordings alone should be used cautiously when SaO2 recordings of 4.4% higher or lower than the observed SpO2 would be of concern. A range of variables relevant to the critically ill had little or no effect on bias.

Timing and climate forcing of volcanic eruptions for the past 2,500 years.

Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.

Metrics of salbutamol use as predictors of future adverse outcomes in asthma.

BACKGROUND: Beta-agonist overuse is associated with adverse outcomes in asthma, however, the relationships between different metrics of salbutamol use and future risk are uncertain. OBJECTIVE: To investigate the relationship between metrics of salbutamol use and adverse outcome. METHODS: In a 24-week randomized controlled trial of 303 asthma patients at risk of severe exacerbations which compared the efficacy and safety of combination budesonide/formoterol inhaler according to a single inhaler regimen (SMART) with a fixed-dose regimen with salbutamol as reliever ('Standard'), actual medication use was measured by electronic monitoring (Australian New Zealand Clinical Trials Registry Number ACTRN12610000515099). A nested cohort study explored the relationship between metrics of baseline salbutamol use over 2 weeks and future severe asthma exacerbations, poor asthma control (ACQ-5 ≥ 1.5) or 'extreme' salbutamol overuse (> 32 salbutamol actuations/24-h period). RESULTS: Higher mean daily salbutamol use (per two actuations/day) [Odds ratio (OR) (95% CI) 1.24 (1.06-1.46)], higher days of salbutamol use (per 2 days in 2 weeks) [OR 1.15 (1.00-1.31)] and higher maximal 24-h use (per two actuations/day) [OR 1.09 (1.02-1.16)] were associated with future severe exacerbations. Higher mean daily salbutamol use was associated with future poor asthma control [OR 1.13 (1.02-1.26)]. Higher mean daily salbutamol use [OR 2.73 (1.84-4.07)], number of days of use [OR 1.46 (1.24-1.71)], and maximal daily use [OR 1.57 (1.31-1.89)] were associated with an increased risk of future extreme salbutamol overuse. CONCLUSION AND CLINICAL RELEVANCE: Electronically recorded frequency of current salbutamol use is a strong predictor of risk of future adverse outcomes in asthma, with average daily use performing the best. These findings provide new information for clinicians considering metrics of salbutamol as predictors of future adverse outcomes in asthma.

Changes in nurses' decision making during a 12-h day shift.

BACKGROUND: Although shift work is necessary in many health-care settings, research suggests that it can have detrimental effects on performance in health-care providers. AIMS: To determine if a change in decision-making occurred across a 12-h day shift in a sample of registered nurses. METHODS: The participants were nurses working a 12-h day shift (7 a.m.-7 p.m.) at a large hospital in the south-eastern USA. Participants completed a policy-capturing questionnaire, examining their likelihood of calling a physician in response to specific patient symptoms, at the beginning and end of the shift. They also completed self-report surveys on alertness, stress and sleepiness. RESULTS: Sixty-five nurses completed the study, an overall response rate of 41%. Participants significantly changed their decision-making policies from the beginning to the end of the work shift and also became significantly less alert and more stressed. However, there was no correlation between decision-making and reported alertness and stress. CONCLUSIONS: These results suggest that medical judgment in registered nurses changed from the beginning to the end of a 12-h day shift. One possible underlying mechanism responsible for the changes seen across the shift could be the ability to maintain attention, as suggested by the Controlled Attention Model. The current results expand upon previous research, indicating there are a variety of negative outcomes associated with shift work.

Applications of transrectal ultrasound in prostate cancer.

Transrectal ultrasound (TRUS) was first developed in the 1970s. TRUS-guided biopsy, under local anaesthetic and prophylactic antibiotics, is now the most widely accepted method to diagnose prostate cancer. However, the sensitivity and specificity of greyscale TRUS in the detection of prostate cancer is low. Prostate cancer most commonly appears as a hypoechoic focal lesion in the peripheral zone on TRUS but the appearances are variable with considerable overlap with benign lesions. Because of the low accuracy of greyscale TRUS, TRUS-guided biopsies have become established in the acquisition of systematic biopsies from standard locations. The number of systematic biopsies has increased over the years, with 10-12 cores currently accepted as the minimum standard. This article describes the technique of TRUS and biopsy and its complications. Novel modalities including contrast-enhanced modes and elastography as well as fusion techniques for increasing the sensitivity of TRUS-guided prostate-targeted biopsies are discussed along with their role in the diagnosis and management of prostate cancer.

Diagnostic accuracy of small intestine ultrasonography using an oral contrast agent in Crohn's disease: comparative study from the UK.

AIM: To evaluate the usefulness of small intestine contrast-enhanced ultrasonography (SICUS) using an oral contrast agent in routine clinical practice by assessing the level of agreement with the established techniques, small bowel follow-through (SBFT) and computed tomography (CT), and diagnostic accuracy compared with the final diagnosis in the detection of small bowel Crohn's disease (CD) and luminal complications in a regional centre. MATERIALS AND METHODS: All symptomatic known or suspected cases of CD who underwent SICUS were retrospectively reviewed. The level of agreement between SICUS and SBFT, CT, histological findings, and C-reactive protein (CRP) level was assessed using kappa (κ) coefficient. Sensitivity was demonstrated using the final diagnosis as the reference standard defined by the outcome of clinical assessment, follow-up, and results of investigations other than SICUS. RESULTS: One hundred and forty-three patients underwent SICUS of these 79 (55%) were female. Eighty-six (60%) were known to have CD and 57 (40%) had symptoms suggestive of intestinal disease with no previous diagnosis. Forty-six (55%) of the known CD patients had had at least one previous surgical resection. The sensitivity of SICUS in detecting active small bowel CD in known CD and undiagnosed cases was 93%. The kappa coefficient was 0.88 and 0.91 with SBFT and CT, respectively. SICUS detected nine patients who had one or more small bowel strictures and six patients with a fistula all detected by SBFT or CT. CONCLUSION: SICUS is not only comparable to SBFT and CT but avoids radiation exposure and should be more widely adopted in the UK as a primary diagnostic procedure and to monitor disease complications in patients with CD.

The feasibility of catheter-directed thrombolysis for acute deep vein thrombosis: a regional perspective.

BACKGROUND: Deep vein thromboses (DVTs) are a significant cause of morbidity and mortality. Valvular destruction leads to the spectrum of disease called the post-thrombotic syndrome (PTS) with the sequelae of chronic venous ulceration and a reduced quality of life. Catheter-directed thrombolysis (CDT) may reduce the incidence of PTS following an acute proximal DVT and increases quality of life thereafter, but it is uncertain what proportion of patients diagnosed with a DVT would be suitable for CDT. METHODS: This study quantified the proportion of patients investigated for DVT that would have been suitable for CDT. A retrospective review was performed of all upper and lower limb duplex ultrasound scans for suspected DVTs in a contemporary one-year period in a major regional vascular institute. All positive scans for acute proximal lower limb DVTs were compared against strict inclusion and exclusion criteria for CDT, based on national guidelines and international randomized trials. RESULTS: A total of 2368 duplex ultrasound venous investigations were performed in a one-year period and 252 scans demonstrated DVT. Of these, 158 were acute proximal lower limb DVTs. Application of the inclusion and exclusion criteria for CDT suggested that 47/158 (30%) were potentially suitable for CDT using current criteria. The median age of the 158 patients was 58 years, meaning that more than half were of working age and 54% were men. CONCLUSION: Using current eligibility criteria, only about 30% of patients with DVT appear to be suitable for CDT.

Prediction of erosion progression using ultrasound in established rheumatoid arthritis: a 2-year follow-up study.

OBJECTIVES: This study aimed to determine whether a range of single-time-point ultrasound (US) measures of synovial disease and serologic characteristics were able to predict progression of US-defined erosive disease in patients with established rheumatoid arthritis (RA). MATERIALS AND METHODS: Forty patients were studied prospectively. At baseline, subjective US measures of bone damage and synovial disease, including grayscale and power Doppler (PD) scores pre- and post-Sonovue contrast, were obtained from one proximal inter-phalangeal or metacarpo-phalangeal joint per patient. After a minimum of 2 years, the same joints were scanned to obtain a new US erosion score. RESULTS: Follow-up US erosion scores were obtained in 25 joints. Progressive US determined that bone damage occurred in 12/25 joints, including four of eight treated with anti-tumor necrosis factor therapy. Baseline erosion scores were significantly higher in joints that did not show progressive bone damage in the entire cohort (p = 0.05, n = 25) and a subgroup treated with disease-modifying anti-rheumatic drugs (p = 0.015, n = 17). There were no other significant differences in baseline US or serologic scores between joints that developed progressive damage and those that did not. CONCLUSIONS: The majority of single-time-point US measures of synovial disease were not able to identify metacarpo-phalangeal or inter-phalangeal joint destined to develop progressive US-determined bone damage in patients with established RA. This may reflect the use of single-time-point measures, insensitivity of the US erosion score, and the long duration of RA disease in this study.

Sentinel lymph node biopsy using dynamic lymphoscintigraphy combined with ultrasound-guided fine needle aspiration in penile carcinoma.

The purpose of this study was to assess the utility of sentinel lymph node lymphoscintigraphy (SLNL) and ultrasound-guided fine needle aspiration cytology (FNAC) in patients with penile carcinoma. A prospective study was undertaken of 64 patients with stage T1 (or greater) clinically N0 squamous cell carcinoma of the penis. Patients underwent SLNL and bilateral groin ultrasonography with or without FNAC. Following intradermal blue dye, patients underwent unilateral or bilateral sentinel lymph node excision biopsy (SNB). 17 patients had sentinel nodes that contained metastases (21 nodal basins). Lymphatic drainage was demonstrated in all patients by lymphoscintigraphy. Bilateral drainage was seen in 57/64 patients. 61/64 patients had ultrasonography of the inguinal basins on the same day as FNAC of 38 basins. FNAC showed malignancy in eight basins. FNAC was negative in six basins, which were subsequently shown to be positive following SNB. 82 inguinal basins did not warrant FNAC by ultrasound criteria, of which 5 contained metastases at SNB. The sensitivity and specificity of ultrasonography was 74% and 77%, respectively. The positive and negative predictive values were 37% and 94%, respectively. Two patients had a negative initial SNB; however, ultrasonography identified a metastatic node and re-evaluation of the sentinel node confirmed micro-metastases. There has been no evidence of recurrence in any patients with negative SNB (during 6-28 months' follow-up). In conclusion, when investigating clinically stage N0 penile cancer, the combination of SNB and groin ultrasonography, with or without FNAC, identifies accurately those with occult nodal metastases. Ultrasonography alone is not adequate as a staging technique, and SNB alone might miss between 5% and 10% of metastases.

The relation between composite ultrasound measures and the DAS28 score, its components and acute phase markers in adult RA.

OBJECTIVES: Ultrasound (US) provides measurements of synovial morphology and vascularity. However, on an individual joint basis in RA, US measures do not relate well to clinical signs. This study investigates the relationship between composite US measures and the 28-joint disease activity score (DAS28), its components and acute phase markers in adult RA. METHODS: RA synovial disease activity was recorded in 50 patients by: (i) the DAS28 score; (ii) ESR and CRP; and (iii) US using Grey scale (GS) and power Doppler (PD) measures of PIP and MCP joints to derive composite US scores based on abnormal counts and severity. A total of 25 control subjects were studied to define normal US appearances. The relation between each measure of synovial disease was determined by Spearman correlation analysis. RESULTS: There was a significant relation between the DAS28 and the GS joint count (GSJC, Spearman's r = 0.4; P = 0.004) and severity score (GSJS, r = 0.34; P = 0.016) and the PD joint count (PDJC, r = 0.32; P = 0.028). There was a significant relation between the ESR and PDJC (r = 0.37; P = 0.007) and PD joint severity score (PDJS, r = 0.38; P = 0.006) and between the CRP and PDJS (r = 0.29; P = 0.04). The remaining components of the DAS28 related poorly to all US measures, except the tender joint count, which related significantly to the GS but not the PD measures. CONCLUSIONS: Composite US markers of synovial disease relate significantly to the DAS28 score and ESR/CRP in adult RA, but not as well with individual clinical joint counts and the patient's global assessment.

A comparison of clinical vs ultrasound determined synovitis in rheumatoid arthritis utilizing gray-scale, power Doppler and the intravenous microbubble contrast agent 'Sono-Vue'.

OBJECTIVES: Synovitis in rheumatoid arthritis (RA) is assessed clinically by the presence of joint tenderness and swelling. Synovial thickening and increased vascularity may also be detected by high-resolution ultrasonography (US) and power Doppler (PD). This study investigated the relationship between clinical and sonographic features of synovial disease utilizing US, PD and the contrast agent Sono-Vue. METHODS: Forty RA patients were recruited. One proximal inter-phalangeal or metacarpophalangeal joint was selected per patient, as being unambiguously either: swollen and tender, just swollen, just tender or neither swollen nor tender (Nil). Ten joints were selected per clinical group. On US, the mean synovial thickness was measured and synovial hypertrophy and erosions were graded subjectively. Synovial vascularity demonstrated by PD was scored subjectively pre- and post-contrast. RESULTS: All grades of synovial vascularity were found in each clinical group including the Nil group. There were significant differences between the four clinical groups for both synovial hypertrophy (P = 0.024) and PD scores pre- (P = 0.022) and post- (P = 0.039) contrast. Tender-only joints showed significantly less vascularity than other groups. Post-contrast, the median PD scores increased in all but the Nil group, in some cases from the normal to abnormal range. CONCLUSION: Synovitis demonstrated by US and PD is not predicted by patterns of disease as described by joint swelling and tenderness despite unambiguous selection of joints. Synovial vascularity was the least in tender-only joints and was heterogeneous in all other groups, including Nil joints. These findings question the reliability of traditional clinical signs in RA synovitis assessment.

Choosing the correct length of ureteric stent: a formula based on the patient's height compared with direct ureteric measurement.

AIM: To evaluate a formula based on the patient's height for choosing the correct length of ureteric stent and to compare its accuracy with that of direct ureteric length measurement. METHODS: Thirty-five patients (41 ureters) with ureteric obstruction were prospectively studied. All received Percuflex 8F double pigtail ureteric stents. Stent lengths were chosen according to patient height: < 5 ft 10 in (<178 cm) = 22 cm; 5 ft 10 in to 6 ft 4 in (178-193 cm) = 24 cm; > 6 ft 4 in (>193 cm) = 26 cm. The final stent position was graded using a 5-point scale (0 representing ideal length, with -2 and +2 being too short and too long respectively). Stent length acceptability using direct ureteric measurement was then estimated using the same 5-point scale; and the results compared. RESULTS: Patient's height correctly predicted stent length in the majority of ureters (grade 0 = 61%), with no stent being too short. In comparison, direct ureteric measurement oversized the stent in 83%, correctly predicting stent length in only 17%. CONCLUSION: Patient's height is a more reliable guide to ureteric stent length than direct ureteric measurement, particularly in the dilated and tortuous ureter. This may be because the redundant ureter is capable of significant shortening under the influence of the ureteric stent.

Problem in diagnostic imaging: Mediastinal venous anomalies.

This article presents as a diagnostic problem a rare mediastinal venous anomaly detected in a patient with a primary intrathoracic tumor. Its appearance on computed tomography (CT) is discussed and compared with that of other developmental mediastinal venous anomalies. The individual CT characteristics of these anomalies and their clinical significance with respect to the management of patients with cancer are also reviewed.

The prevalence of daytime napping and its relationship to nighttime sleep.

Many healthy adults report daytime napping. Surprisingly few studies, however, have examined spontaneous napping behavior, especially very short naps, in healthy adults. The authors examined the prevalence of power naps (lasting less than 20 minutes) and longer naps (20 minutes or more) and their effects on nighttime sleep in a group of healthy young and middle-aged adults. The young and middle-aged adults reported very similar sleep and napping patterns, with approximately 74% of the participants in both groups reporting they had napped during a 7-day sleep-log period. Almost half of the participants reported that the average nap lasted less than 20 minutes. A multivariant analysis of variance (MANOVA) found no significant differences between the no-nap and the power-nap or long-nap groups in sleep quantity or quality for either age group. The current data suggested that power napping occurs frequently in healthy adults and that spontaneous napping does not negatively affect nighttime sleep.

Work/rest cycles in railroad operations: effects of shorter than 24-h shift work schedules and on-call schedules on sleep.

The current study examined the frequency with which shorter than 24-h work/rest cycles occur in locomotive engineer work schedules, and what effects these work/rest cycles had on sleep quantity and sleep quality. The results indicated that shorter than 24-h work/rest cycles occurred in 33.6% of the work days reported by 198 locomotive engineers. In addition, the shorter than 24-h work/rest cycles occurred more frequently in work schedules that created an on-call work system, such as road pool turn and extra board assignments, than in work schedules that used more predictable or regular work times, such as regular road assignments and yard/local work. As would be expected, when engineers worked shorter than 24-h work/rest cycles, they reported less sleep and poorer sleep than under the longer than 24-h work/rest cycles. Similarly, on-call work assignments resulted in less sleep and poorer sleep than regular work assignments. These results indicate that specific aspects of the work schedules used in railroad operations, particularly on-call operations that result in shorter than 24-h work/rest cycles, can lead to increased sleep-related problems. Although the North American railroad industry is making significant changes in on-call operations to minimize sleep-related problems from on-call schedules, better fatigue-related models validated within the railroad industry are needed.

Self-report sleep habits as predictors of subjective sleepiness.

Although sleepiness is pervasive in our society, there is little agreement on how to measure sleepiness or on how well sleepiness is actually related to sleep habits. To better assess how subjective sleepiness is related to sleep, the authors used self-report measures of sleep quantity, sleep quality, and napping to predict 4 different sleepiness-related measures in a group of healthy young and middle-aged-to-older adults. A forward regression analysis indicated that sleep quality was better than sleep quantity as a predictor of participants' sleepiness. The sleep measures, furthermore, predicted sleepiness better in the older adults than in the younger adults. Finally, the 4 sleepiness measures differed in how well they were related to sleep. The findings in the study suggest that sleepiness is a complex phenomenon rather than a simple reflection of sleep quantity.

Differential effects of permanent and rotating shifts on self-report sleep length: a meta-analytic review.

STUDY OBJECTIVES: The current study used the meta-analytic technique to quantitatively assess the effects of permanent and rotating shift-work schedules on sleep length. DESIGN: A meta-analysis was completed on 36 primary studies resulting in 165 effect sizes. Effect sizes comparing shift-workers to a permanent day shift control group were calculated for permanent evening shifts, permanent night shifts, and morning, evening, and night shifts worked as part of slowly and rapidly rotating shift systems. SETTING: NA PATIENTS OR PARTICIPANTS: NA INTERVENTIONS: NA RESULTS: Permanent night shifts resulted in a decrease, whereas permanent evening shifts resulted in an increase in sleep length. The shifts within rotating schedules followed the same pattern, with the addition of morning shifts having a moderate detrimental effect on sleep length. Furthermore, the speed of shift rotation had an impact. Slowly rotating shifts, in general, had the least detrimental effect on sleep length of the permanent and rotating shift-work schedules studied here. The pattern of effects among morning, evening, and night shifts was the same for rapidly and slowly rotating shifts, with night shifts having the greatest detrimental effect, morning shifts having a moderate detrimental effect and evening shifts having a positive effect on sleep length. In addition, nights on rotating shifts had a greater negative effect on sleep length than permanent night shifts. CONCLUSIONS: Slowly rotating shifts have the least negative impact on sleep length of shift-work schedules including a night shift. However, permanent night shifts could be an alternative shift-work schedule in operational settings that require many workers at night.

Left upper lobe bronchus reimplantation for nonpenetrating thoracic trauma.

Trauma to the tracheobronchial tree has been diagnosed and treated with increasing frequency over the last several decades. However, most reports have dealt with management of injuries to the trachea and main stem bronchi, as approximately 80% of blunt tracheobronchial injuries occur within this area. With few exceptions, injury to the lobar bronchi has resulted in thoracotomy and lobectomy. We describe a patient with an injury to the left upper lobe bronchus who presented with delayed obstruction of the airway by fibrogranulation tissue. A successful segmental resection of the bronchial occlusion with reimplantation was performed, thereby preserving the patient's otherwise normal left upper lobe. This case demonstrates that resection and reimplantation of an injured lobar bronchus are feasible, even in a delayed setting.

The prevalence of asymptomatic carotid artery disease in patients with peripheral vascular disease.

AIM: To determine the prevalence and severity of asymptomatic carotid artery disease in patients with peripheral arterial disease using colour duplex ultrasound, and to determine any relationship to the severity of peripheral arterial disease or other associated atherosclerotic risk factors. METHOD: Two hundred patients with known peripheral arterial disease but no previous cerebrovascular history were prospectively screened for carotid artery disease, and any identified internal carotid artery (ICA) stenosis graded using established duplex ultrasound criteria. A detailed medical questionnaire established the presence or absence of associated risk factors, and the severity of peripheral arterial disease was graded and correlated with these. RESULTS: A total of 50 patients (25%) were found to have an ICA stenosis of > 50%, with 27 (13.5%) of these having > 70% stenosis. Bilateral ICA stenosis (> 50%) was seen in 21 (10.5%) patients, of which 10 (5%) had bilateral stenoses of > 70%. No correlation was found between the severity of peripheral arterial disease and the presence of significant carotid artery disease, or between the latter and individual atherosclerotic risk factors. CONCLUSION: This study demonstrates a relatively high prevalence of significant carotid artery disease in patients with peripheral arterial disease compared to the general population. The significance of this with respect to the future screening of defined populations for asymptomatic carotid artery disease is discussed, with reference to recent studies comparing surgical and medical management of asymptomatic carotid artery disease.

Accuracy of surgeon-performed gallbladder ultrasound.

BACKGROUND: Symptomatic cholelithiasis is among the most common of general surgery referrals. With an appropriate clinical presentation, definitive diagnosis requires documentation of gallstones by ultrasonography (US). The authors evaluated the accuracy of surgeon-performed US for identifying gallstones in patients with a nonacute indication for study. METHODS: Patients referred for symptomatic cholelithiasis and who provided informed consent received an US examination by one or more of the surgical investigators. Surgeon-performed US findings were correlated with radiologist US findings and pathologic diagnoses. RESULTS: Seventy-seven patients received a total of 128 examinations by the investigators. Surgeon-performed US examination agreed with the radiologist US findings for 112 of 122 studies (92%) with a sensitivity of 100% and a specificity of 95%. Surgeon-performed US findings correlated with the pathologic diagnoses for 83 of 86 studies (97%). CONCLUSIONS: Surgeons can perform gallbladder US in the nonacute setting with a high degree of accuracy.