Acute kidney injury requiring hemodialysis in patients with anicteric leptospirosis.

BACKGROUND: Leptospirosis is an infrequent disease in the US, with most cases reported in the state of Hawaii. Renal involvement is common (44 - 67%), ranging from a mild prerenal azotemia in anicteric disease to renal failure requiring dialysis in Weil's syndrome (severe leptospirosis with jaundice, renal failure, and hemorrhage). METHODS: To describe the pattern of leptospiral renal disease at our institution, we performed a retrospective analysis (1992 - 2004) of all hospitalized cases of laboratory confirmed leptospirosis presenting with acute kidney injury (AKI), defined as a presenting serum creatinine > 1.5 mg/dl. RESULTS: During this time period, 18 patients were hospitalized with laboratory confirmed leptospirosis. Among these patients, 12 had AKI on presentation, and hemodialysis was required in 3 patients. Renal biopsies were performed in 2 of these patients, revealing acute tubulointerstitial nephritis. Interestingly, the patients who required dialysis did not have Weil's syndrome. They did not exhibit jaundice or hemorrhage, and serum AST (mean 51.7 U/l (range 36 - 60)), ALT (mean 51.0 U/l (range 38 - 64)), and total bilirubin (mean 1.2 mg/dl (range 0.8 - 1.8)) were either within normal limits or only slightly elevated, despite having the worst renal disease. CONCLUSIONS: This series adds to other evidence that severe AKI (requiring dialysis) can complicate anicteric leptospirosis in contrast to the notion that the AKI in anicteric disease is typically mild and prerenal. Leptospirosis should be considered in all patients who present with fever and AKI, especially if associated with thrombocytopenia or travel to an endemic area.

Predicting communication skills with a paper-and-pencil test.

AIM: This study was conducted to investigate the value of a written knowledge test of communication skills for predicting scores on a performance test of communication skills. METHOD: A paper-and-pencil test of knowledge about communication skills and a performance test of communication skills, consisting of four stations with standardised patients, were administered to students of two classes of the medical schools of Maastricht and Leiden, the Netherlands. The results on these tests were compared. RESULTS: From the results of both instruments, the classes of the participating students could be recognised equally well: 60% correct qualifications of the classes by the knowledge test and 64% by the multiple station examination. Between the two tests an overall, disattenuated correlation of 0.60 was found (N=133, P < 0.01), suggesting moderate predictive value of the knowledge test for the performance test of communication skills. The correlation is stronger for students from Maastricht medical school than for their colleagues in Leiden. Correlation between the knowledge of communication skills test and other available test results of the participating Maastricht students is close to zero, suggesting that the test measures a distinct quality of students' competence. DISCUSSION: The paper-and-pencil test of knowledge of communication skills has predictive value for the performance of these skills, but this value seems to be less pronounced than similar findings for clinical procedural skills. The stronger relationship between 'knowing how' and 'showing' in the Maastricht student group might be indicative of an effect of the training format.

Longitudinal and concentrated communication skills programmes: two dutch medical schools compared.

AIM OF THE STUDY: The communication skills of students of the Dutch medical schools of Maastricht and Leiden were compared, to assess the effectiveness of these schools' different approaches to communication skills training. Both schools have a six-year undergraduate medical curriculum, divided into four preclinical years and two years of clinical clerkships. The Maastricht problem-based curriculum offers an integrated clinical skills training programme, including communication skills, which runs throughout the first four years. Communication skills training in Leiden is concentrated in courses in the preclinical phase, at the beginning of the clinical phase and preceding two clerkships. METHOD: Communication skills of fourth-year and sixth-year students (N = 161) of both universities were assessed using four OSCE stations in which students did entire consultations with standardised patients. Trained observers rated these consultations, using a checklist. RESULTS: Maastricht students of both year groups obtained significantly higher checklist scores for their communication skills than their Leiden colleagues. The Leiden students' scores increase between years 4 and 6, whereas those of the Maastricht students showed no significant change. DISCUSSION: The higher scores obtained by the Maastricht students indicate a greater overall effectiveness of a longitudinal, integrated approach compared with concentrated courses. Absence of formal training in the clinical phase in Maastricht leads to stabilisation of communication skills, whereas the increase in the Leiden students' scores between years 4 and 6 offers evidence that formal communication skills training during the clinical phase does pay off. These findings suggest that the preferred approach to communication skills training would be an integrated, longitudinal programme, which continues during the clinical years.

Computer keyboards and faucet handles as reservoirs of nosocomial pathogens in the intensive care unit.

PURPOSE: We postulate that computer keyboards and faucet handles are significant reservoirs of nosocomial pathogens in the intensive care unit (ICU) setting. METHODS: Sterile swab samples were obtained from 10 keyboards and 8 pairs of faucet handles in the medical ICU at Tripler Army Medical Center during a period of 2 months. Methicillin-resistant Staphylococcus aureus (MRSA) obtained from the environmental and patient specimens were sent for DNA identification by using pulsed-field gel electrophoresis. RESULTS: A total of 144 samples were obtained (80 keyboards and 64 faucet handles), yielding 33 isolates. The colonization rate for keyboards was 24% for all rooms and 26% in occupied rooms. Rates for faucet handles in all rooms and occupied rooms were 11% and 15%, respectively. The environmental isolates annd their prevalence were: MRS, 49%; Enterococcus, 18%; Enterobacter, 12%; and all other gram-negative rods, 21%. Fourteen individual patient isolates were recorded: MRSA, 43%; Enterobacter, 21%; other gram-negative rods, 36%; and Enterococcus, 0%. By using pulsed-field gel electrophoresis, an indistinguishable strain of MRSA was identified in two patients, the keyboards and faucet handles in their respective rooms, and on other keyboards throughout the ICU, including the doctors' station. CONCLUSIONS: The colonization rate for keyboards and faucet handles, novel and unrecognized fomites, is greater than that of other well-studied ICU surfaces in rooms with patients positive for MRSA. Our findings suggest an associated pattern of environmental contamination and patient infection, not limited to the patient's room. Pulsed-field gel electrophoresis results have documented an indistinguishable strain of MRSA present as an environmental contaminant on these two fomites and in two patients with clinical infections patients during the same period. We believe these findings add evidence to support the hypothesis that these particular surfaces may serve as reservoirs of nosocomial pathogens and vectors for cross-transmission in the ICU setting. New infection control policies and engineering plans were initiated on the basis of our results.

Symptomatic vascular rings in adulthood: an uncommon mimic of asthma.

Symptomatic thoracic vascular rings presenting in adulthood are thought to be rare. During a 3-year time period, we diagnosed four cases of symptomatic vascular rings, which had been treated unsuccessfully for suspected asthma. Spirometry was characterized by normal forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), and FEV1/FVC, decreased peak expiratory flow (PEF), and truncation of the expiratory flow volume loop. Chest radiographs revealed a right aortic arch in each case with computed tomography (CT) or magnetic resonance imaging (MRI) confirming the diagnosis of a vascular ring. The specific abnormalities consisted of right aortic arch with mirror branching of the main arteries and persistent ligamentum arteriosum; right aortic arch with diverticulum and a fibrous embryonic left arch; right aortic arch with aberrant left subclavian artery arising from a diverticulum of Kommerell; and a right aortic arch with persistent ligamentum arteriosum. Although they are uncommon, vascular rings first presenting in adulthood as a mimic of asthma are not rare. This diagnosis should be considered in adults when abnormal truncation of the flow-volume loop occurs or when radiographic aortic arch abnormalities are found.

Lung function during moderate hypobaric hypoxia in normal subjects and patients with chronic obstructive pulmonary disease.

BACKGROUND: We sought to describe changes in spirometric variables and lung volume subdivisions in healthy subjects and patients with chronic obstructive pulmonary disease (COPD) during moderate acute hypobaric hypoxia as occurs during air travel. We further questioned whether changes in lung function may associate with reduced maximum ventilation or worsened arterial blood gases. METHODS: Ambulatory patients with COPD and healthy adults comprised the study populations (n = 27). We obtained baseline measurements of spirometry, lung volumes and arterial blood gases from each subject at sea level and repeated measurements during altitude exposure to 8000 ft (2438 m) above sea level in a man-rated hypobaric chamber. RESULTS: Six COPD patients and three healthy subjects had declines in FVC during altitude exposure greater than the 95% confidence interval (CI) for expected within day variability (p < 0.05). Average forced vital capacity (FVC) declined by 0.123 +/- 0.254 L (mean +/- SD; 95% CI = -0.255, -0.020; p < 0.05) for all subjects combined. The magnitude of decline in FVC did not differ between groups (p > 0.05) and correlated with increasing residual volume (r = -0.455; <0.05). Change in maximum voluntary ventilation (MVV) in the COPD patients equaled -1.244 +/- 4.797 L x min(-1) (95% CI = -3.71, 1.22; p = 0.301). Decline in maximum voluntary ventilation (MVV) in the COPD patients correlated with decreased FVC (r = 0.630) and increased RV (r = -0.546; p < 0.05). Changes in spirometric variables for patients and controls did not explain significant variability in the arterial blood gas variables PaO2, PaCO2 or pH at altitude. CONCLUSIONS: We observed a decline in forced vital capacity in some COPD patients and normal subjects greater than expected for within day variability. Spirometric changes correlated with changes in reduced maximum voluntary ventilation in the patients but not with changes in resting arterial blood gases.

Hemodynamic effects of altitude exposure and oxygen administration in chronic obstructive pulmonary disease.

PURPOSE: Cardiovascular events are the leading cause of death during air travel. Because patients with chronic obstructive pulmonary disease (COPD) develop severe hypoxemia at altitude, we sought to determine whether changes in systemic hemodynamics may contribute to health risks during hypobaric hypoxia. PATIENTS AND METHODS: We recorded radial artery catheter blood pressure, cardiac frequency, and cardiac ectopy in 18 men (aged 68 +/- 6 years, mean +/- SD) with severe COPD (forced expiratory volume in 1 second 0.97 L +/- 0.32 L) at sea level, after 45 minutes of steady-state hypobaric hypoxia at 2,438 m in a hypobaric chamber, and after oxygen supplementation at 2,438 m. RESULTS: Mean arterial pressure (mm Hg), systolic blood pressure (SBP), diastolic blood pressure, and pulsus paradoxus during acute hypobaric exposure did not differ from baseline. During oxygen supplementation, SBP declined (p = 0.028). Decreases in pulsus paradoxus and pulse pressure were noted on oxygen (p < 0.05). We found no changes in cardiac frequency. Cardiac ectopy was uncommon; for one subject, ectopy increased with hypobaric hypoxia and decreased with oxygen administration. CONCLUSION: Vasopressor responses to hypoxia do not add to the risk of air travel in patients with severe COPD. Supplemental oxygen may cause beneficial hemodynamic changes in patients with COPD during acute hypobaric exposure.

Hypoxemia during altitude exposure. A meta-analysis of chronic obstructive pulmonary disease.

A previous study identified spirometric testing as a useful adjunct for estimating PaO2 during altitude exposure in patients with chronic obstructive pulmonary disease (COPD). We sought to examine the validity of this finding by quantitative analysis of recent published reports. We analyzed acute hypoxic exposures from five prior studies involving 71 patients. Across all studies, the change in arterial oxygen tension per unit change in inspired oxygen partial pressure (linear slope, dPaO2/dP1O2) correlated with the preexposure forced expiratory volume in 1 s (FEV1, p < 0.01). The correlation with FEV1 held for values weighted or unweighted by sample size, with rotating deletion of each study from analysis one at a time, and with semilog slope as the dependent variable. A formula derived from the semilog slope relationship with FEV1 gave accurate description of the mean hypoxic response in each prior study and individual responses from one study (n = 18): ln (PaO2alt/PaO2g) = Kn.(PIO2alt-PIO2g). We found that FEV1 modulated the values of kn in this study. We conclude, based on analysis of prior studies, that preexposure arterial oxygen tension and FEV1 both influence the prediction of PaO2 during hypoxic exposures in patients with COPD.

Pasteurella multocida pneumonia in a man with AIDS and nontraumatic feline exposure.

A case of acute pneumonia due to Pasteurella multocida ssp multocida occurred in a young man with AIDS and chronic sinusitis. The pneumonia was diagnosed by bronchoscopy and responded to treatment with aztreonam. Epidemiologic investigation revealed the case was temporally related to nontraumatic exposure to cat secretions that the patient presumably had acquired via an aerosol. The cat's oral cavity was cultured and an isolate of P multocida ssp multocida with identical biochemical reactions, DNA restriction patterns, and nearly identical fatty acid profile to that of the patient's isolate was obtained suggesting they were identical strains and therefore epidemiologically linked. A control strain with identical biochemical reactions and antibiotic sensitivities exhibited different patterns. To our knowledge, this is the first such reported infection in a patient infected with human immunodeficiency virus.

Oxygen supplementation during air travel in patients with chronic obstructive lung disease.

The objective of this study was to quantitate the effects of O2 supplementation by nasal cannula (NC) and Venturi mask (VM) on PaO2 in patients with chronic obstructive pulmonary disease (COPD) during acute hypobaric exposure, simulating a commercial jet aircraft cabin. We conducted a crossover intervention trial in which subjects served as their own controls in an ambulatory outpatient pulmonary disease service of a tertiary care military medical center and a hypobaric research facility. The subjects were a volunteer sample of 18 men with stable severe COPD, not requiring long-term O2 therapy, and uncomplicated by hypercapnea or cardiac disease. Mean age was 68 years, and mean FEV1 was 0.97 L (31.3 percent predicted). We exposed patients to conditions equivalent to 8,000 feet in a hypobaric chamber. Radial artery catheters provided blood samples at ground level and 8,000 feet. O2 was sequentially administered at 8,000 feet by NC at 4 L/min and 24 percent or 28 percent VM. We describe changes in blood gas data from baseline values and between interventions. O2 at 4 L/min NC flow at 8,000 feet caused PaO2 to increase from 47.4 +/- 6.3 mm Hg to 82.3 +/- 14 mm Hg (n = 18), an increase of 34.9 +/- 14.8 mm Hg. Supplementation of O2 by 24 percent VM caused PaO2 at 8,000 feet to increase by 12.7 +/- 3.8 mm Hg. Twenty-eight percent VM caused PaO2 at 8,000 feet to increase by 19.7 +/- 8.2 mm Hg. Changes in PaO2 with 4 L/min NC were greater than those with either VM. The increase with 28 percent VM was greater than that caused by 24 percent VM (p less than 0.05). Compared with ground level, 4 L/min NC increased mean PaO2 by 9.9 +/- 12.6 mm Hg; 24 percent and 28 percent VM did not cause mean PaO2 to increase above ground level values. We describe a range of capability of familiar O2 therapy devices to increase PaO2 to levels that will maintain tissue oxygenation of patients during acute altitude exposure.

Screening for micro-albuminuria with Micro-Bumintest tablets and albumin/creatinine ratio.

The value of Micro-Bumintest tablets and the albumin/creatinine ratio in first morning (FM) urine samples to screen for micro-albuminuria in diabetic patients was evaluated. The A/C ratio in FM urine was highly correlated with the urinary albumin excretion (UAE) rate in micrograms/min in timed overnight (0) urine (R = 0.95, p < 0.001). The sensitivity, specificity and positive and negative predictive values of an A/C ratio > 3.0 to predict micro-albuminuria defined as an UAE > 20 micrograms/min were 94, 92, 92 and 94% respectively. The day-to-day fluctuation of albumin excretion varied between 10 and 105%. The sensitivity, specificity and positive and negative predictive values of micro-bumintest tablet reactions on FM urine samples to predict an A/C ratio > 3.0 were 93, 59, 63 and 91% respectively. It is concluded that for screening of micro-albuminuria the A/C ratio in FM urine is as precise as timed 0 urine collection, but with more comfort for the patient. Micro-Bumintest tablets are useful as an initial screening test and will decrease the number of quantitative albumin measurements in the screening programme by about 30% if only urine samples with positive tablet test are selected for a further investigation. Because of considerable day-to-day fluctuation of urinary albumin excretion several urine samples should be investigated before presence of incipient diabetic nephropathy is assumed.

Air travel in patients with chronic obstructive pulmonary disease.

Air travel exposes patients with chronic obstructive pulmonary disease to the risk of severe hypoxemia. We sought to determine the frequency and outcome of airline travel in patients with chronic obstructive pulmonary disease. A cohort of 100 patients (76 men and 24 women; age 67 +/- 7 years [mean +/- SD]) with severe chronic pulmonary obstructive disease examined by means of spirometry (forced expiratory volume in the first second, 0.04 +/- 0.35 L), all military retirees, or their dependents, comprised the study population. Forty-four patients traveled by commercial air carrier over a 28-month interval, giving an annual frequency of 18.9% of these patients per year. The group that did not travel by air (n = 56) had a lower mean value for forced expiratory volume in the first second and greater prevalence of home oxygen use than did the group that did travel by air. Twelve of the travelers (27.3%) consulted a physician beforehand. Flights reached foreign destinations for 22.7% of patients. The median duration of the longest flight segment was 3 hours. A minority of patients (34.3%) occupied seats in the smoking sections of aircraft. A majority (56.8%) ambulated aboard the aircraft during flights. Eight patients (18.2%) reported transient symptoms during air travel. We conclude that patients with chronic obstructive pulmonary disease travel with appreciable frequency, often without medical consultation, and develop symptoms in some cases.

Accuracy of oxyhemoglobin saturation monitors during simulated altitude exposure of men with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) are at risk for hypoxemia during air travel. We assessed the comparative performance of oxyhemoglobin saturation (%O2Hb) monitors on these patients during hypobaric exposure. We measured %O2Hb by arterial catheter blood co-oximetry (COOX) and compared these values to those from a transmittance ear oximeter and a reusable digital pulse oximeter. Additionally, we examined the effect of oxygen supplementation (4 L/min) on %O2Hb. A total of 18 ambulatory males with severe COPD were exposed to 8,000 ft (565 mm Hg) in a hypobaric chamber. Multiple measures of %O2Hb were made with each monitor at sea level and at 8,000 ft, with and without supplemental oxygen. By COOX, %O2Hb fell at altitude to clinically significant levels, and was subsequently corrected with supplemental oxygen. Saturations measured by the transmittance ear oximeter were very close to the COOX, underestimating the true value by only 0.6% at altitude (p less than 0.05), while the reusable digital pulse oximeter over-estimated %O2Hb alinearly by a mean of 3.8% at altitude.

Influence of fluid removal during haemodialysis on macro- and skin microcirculation. Haemodynamic pathophysiologic study of fluid removal during haemodialysis.

Changes of macro- and microcirculation during haemodialysis and fluid removal are probably dependent on ultimate fluid status and on the efficacy of various regulation mechanisms, especially the catecholamines. This was studied in 20 chronic dialysis patients. Pre- and postdialysis stroke volume, mean arterial pressure, heart rate and systemic vascular resistance were measured. Furthermore, microcirculation was studied by Laser Doppler flow and by intravital microscopy of finger nail fold, measuring red blood cell velocity and capillary density. Pre- and postdialysis noradrenaline and adrenaline were measured. Nine patients proved to be hypovolaemic after dialysis (group I) and 11 patients proved to be normovolaemic or less hypervolaemic (group II) according to vena cava inferior parameters. There was a significant decrease of mean arterial pressure and stroke volume in group I, and an increase of heart rate, whereas in group II there was only a decrease of mean arterial pressure. Systemic vascular resistance did not change in both groups. Noradrenaline decreased although not significantly in both groups, whereas in group I adrenaline increased significantly. There was a significant decrease of skin perfusion in group I, whereas in group II there was a significant increase. Capillary density increased significantly in group II after reaching normovolaemia. Underhydration was leading to a decrease of skin microcirculation on the basis of a decrease of stroke volume and an increase of adrenaline levels. In hypervolaemic patients, who were ultrafiltrated to normovolaemia, skin microcirculation improved on the basis of a decrease of arterial and venous pressure and consequently a decrease of the myogenic response as a local autoregulatory effect.

Hypoxemia during air travel in patients with chronic obstructive pulmonary disease.

STUDY OBJECTIVE: To quantitate and identify determinants of the severity of hypoxemia during air travel in patients with chronic obstructive pulmonary disease. DESIGN: Prospective study of physiologic variables before and during intervention. SETTING: Referral-based pulmonary disease clinic at a U.S. Army medical center. PATIENTS: Eighteen ambulatory retired servicemen (age 68 +/- 6 [SD] years) with severe chronic obstructive pulmonary disease (forced expiratory volume in the first second [FEV1] 31% +/- 10% of predicted). INTERVENTION: Altitude simulation equivalent to 2438 meters (8000 feet) above sea level in a hypobaric chamber. MEASUREMENTS AND MAIN RESULTS: Radial artery catheter blood oxygen tension in the patients declined from a ground value (PaO2G) at sea level of 72.4 +/- 9 mm Hg to an altitude value (PaO2Alt) of 47.4 +/- 6 mm Hg after 45 minutes of steady state hypobaric exposure. The PaO2G correlated with PaO2Alt (r = 0.587; P less than 0.01). Multiple regression analysis revealed that the preflight FEV1 reduced the variability in PaO2Alt not explained by PaO2G in the equation: PaO2Alt = 0.453 [PaO2G] + 0.386 [FEV1% predicted] + 2.440 (r = 0.847; P less than 0.001). Residuals from two previously published formulas using PaO2G also correlated with FEV1 (r greater than or equal to 0.765; P less than 0.001). CONCLUSIONS: Arterial blood oxygen tension declined to clinically significant levels in most patients during hypobaric exposure. When combined with the preflight arterial PO2 at ground level (PaO2G), the measurement of the preflight FEV1 improved prediction of PaO2 at altitude (PaO2Alt) in patients with severe chronic obstructive pulmonary disease.

Plasma alpha-human atrial natriuretic peptide and volume status in chronic haemodialysis patients.

The relationship between inferior vena cava diameter (VCD), collapse-index (CI) determined by echography, and alpha-human atrial natriuretic peptide (alpha-h-ANP) concentrations were studied in 19 chronic haemodialysis patients. A significant correlation was found between VCD and alpha-h-ANP before dialysis (r = 0.78; P less than 0.0001). No such correlation was found between CI, left atrial diameter and left ventricular end-diastolic diameter, and alpha-h-ANP values. In nine patients who according to vena cava indices were hypervolaemic before dialysis (group I), alpha-h-ANP concentrations were significantly greater than in ten normo- or hypovolaemic patients (group II): 392.8 +/- 134.1 pg/ml and 168.0 +/- 62.5 pg/ml respectively. Although the same amount of fluid was ultrafiltrated in both groups, alpha-h-ANP decreased significantly in group I only, whereas in group II the decrease was not significant: 392.8 +/- 134.1 to 185.2 +/- 81.7 (P less than 0.001); 168.0 +/- 62.5 to 130.0 +/- 59 respectively. After achieving normovolaemia alpha-h-ANP concentrations in patients with a mitral valve insufficiency grade I was doubled compared to normovolaemic patients without mitral valve insufficiency, suggesting that alpha-h-ANP release will also occur from the left atrium. In the latter group alpha-h-ANP values were approximately doubled compared to healthy controls. The highly significant correlation between VCD before dialysis and changes in alpha-h-ANP during dialysis with fluid removal underlines the value of vena cava diameter in estimating volume status.