Screening for asymptomatic deep vein thrombosis in COVID-19 patients admitted to the medical ward: a cross-sectional study

Purpose

Patients with COVID-19 have an increased risk for venous thrombo-embolism (VTE), especially pulmonary embolism. The exact prevalence of asymptomatic DVT is not known, as is the usefulness of screening for DVT in patients admitted to ward with COVID-19. We have studied the prevalence of asymptomatic DVT.

Methods

We performed a cross-sectional observational multi-center study at four university medical centers in The Netherlands. All adult patients admitted with COVID-19 to a medical ward were eligible for inclusion, including patients who were transferred back from the ICU to the ward. The study protocol consisted of weekly cross-sectional rounds of compression ultrasound.

Results

In total, 125 patients were included in the study. A significant proportion of patients (N = 34 (27%)) had developed a VTE during their admission for COVID-19 before the study ultrasound was performed. In most VTE cases (N = 27 (79%)) this concerned pulmonary embolism. A new asymptomatic DVT was found in 5 of 125 patients (4.0%; 95% CI 1.3–9.1%) (Table 2). Nine patients (7.2%; 95% CI 3.3–13.2%) developed a VTE (all PE) diagnosed within 28 days after the screening US was performed.

Conclusion

We have shown a low prevalence (4%) of newly discovered asymptomatic DVT outside the ICU-setting in COVID-19 patients. Despite this low prevalence, nine patients developed PE (7%) within 28 days after ultrasound. This favors the hypothesis of local thrombus formation in the lungs. Based on our findings and literature, we do not recommend US-screening of asymptomatic patients with COVID-19 admitted to the ward.

Correspondence - Evaluation of a basic point-of-care ultrasound course for residents in internal medicine

Point-of-care ultrasound (POCUS) integrates imaging into the physical examination at the bedside. This offers the advantage of instant clinical information and has shown to speed up the diagnostic process, and to improve diagnostic accuracy and correct treatment.

Comparison between myocardial function assessed by echocardiography during hospitalization for COVID-19 and at 4 months follow-up

In patients hospitalized for corona virus infectious disease 19 (COVID-19) it is currently unknown whether myocardial function changes after recovery and whether this is related to elevated cardiac biomarkers. In this single center, prospective cohort study we consecutively enrolled hospitalized COVID-19 patients between 1 April and 12 May 2020. All patients underwent transthoracic echocardiography (TTE) evaluation during hospitalization and at a median of 131 days (IQR; 116–136) follow-up. Of the 51 patients included at baseline, 40 (age: 62 years (IQR; 54–68), 78% male) were available for follow-up TTE. At baseline, 68% of the patients had a normal TTE, regarding left ventricular (LV) and right ventricular (RV) volumes and function, compared to 83% at follow-up (p = 0.07). Median LV ejection fraction (60% vs. 58%, p = 0.54) and tricuspid annular plane systolic excursion (23 vs 22 mm, p = 0.18) were comparable between hospitalization and follow-up, but a significantly lower RV diameter (39 vs. 34 mm, p = 0.002) and trend towards better global longitudinal strain (GLS) (− 18.5% vs − 19.1%, p = 0.07) was found at follow-up. Subgroup analysis showed no relation between patients with and without elevated TroponinT and/or NT-proBNP during hospitalization and myocardial function at follow-up. Although there were no significant differences in individual myocardial function parameters at 4 months follow-up compared to hospitalisation for COVID-19, there was an overall trend towards normalization in myocardial function, predominantly due to a higher rate of normal GLS at follow-up.

Correction to: A point-of-care thoracic ultrasound protocol for hospital medical emergency teams (METUS) improves diagnostic accuracy

An amendment to this paper has been published and can be accessed via the original article.

[POCUS is a great asset to general practice]

Point of care ultrasonography (POCUS) is a specific form of ultrasonography that aims to quickly rule in or out specific abnormalities with a high impact on diagnostic or therapeutic management as an adjunct to physical examination. As such, it is of great value to every physician who performs physical examinations, especially if there is an acute problem that may involve several organ systems.

The implementation of POCUS and POCUS training for residents: the Rijnstate approach

Point-of-care ultrasound (POCUS) is gaining interest in intensive care medicine and good reviews and guidelines on POCUS are available. Unfortunately, how to implement POCUS and practical examples how to train staff and junior doctors is not well described in literature. We discuss the process of POCUS implementation, and a POCUS training program for residents prior to their intensive care rotation in a Dutch teaching hospital intensive care unit. The described four-day basic POCUS course consists of short tutorials and ample time for hands-on practice. Theoretical tests are taken shortly before, on the last day of the course, and after three months to assess learning retention. Practical tests are taken on the last day of the course and after three months. We stress the importance of POCUS for intensive care and hope that our experiences will help colleagues who also want to go forward with POCUS.

Point-of-care ultrasound in internal medicine: A position paper by the ultrasound working group of the European federation of internal medicine

Point-of-care ultrasound (POCUS) is increasingly used to assess medical patients. It has many uses in daily clinical practice, including improved diagnostic timeliness and accuracy, and providing information about a patient's prognosis and follow-up. It has been integrated into numerous specialities, but remains relatively undefined in internal medicine training programs. Ultrasonography is a useful tool in the standard clinical practice of internists in numerous clinical scenarios (Emergency Department, hospital ward, general and specific consultations, and home care). Although POCUS has been recently included in the European curriculum of internal medicine, there are differences between European internists in its use, ranging from not at all to well structured educational programs. The use of POCUS needs to be widespread in internal medicine departments, and to accomplish this we must encourage structured training. This document details the consensus-based recommendations by the European Federation of Internal Medicine (EFIM) Ultrasound working group. We establish POCUS core competencies and clinical settings for internists in a symptom-based approach. We also propose training requirements, providing a framework for training programs at a national level.

The use of an external ultrasound fixator (Probefix) on intensive care patients: a feasibility study

Background

In critical care medicine, the use of transthoracic echo (TTE) is expanding. TTE can be used to measure dynamic parameters such as cardiac output (CO). An important asset of TTE is that it is a non-invasive technique. The Probefix is an external ultrasound holder strapped to the patient which makes it possible to measure CO using TTE in a fixed position possibly making the CO measurements more accurate compared to separate TTE CO measurements. The feasibility of the use of the Probefix to measure CO before and after a passive leg raising test (PLR) was studied. Intensive care patients were included after detection of hypovolemia using Flotrac. Endpoints were the possibility to use Probefix. Also CO measurements with and without the use of Probefix, before and after a PLR were compared to the CO measurements using Flotrac. Side effects in terms of skin alterations after the use of Probefix and patient’s comments on (dis)comfort were evaluated.

Results

Ten patients were included; in eight patients, sufficient recordings with the use of Probefix could be obtained. Using Bland–Altman plots, no difference was found in accuracy of measurements of CO with or without the use of Probefix before and after a PLR compared to Flotrac generated CO. There were only mild and temporary skin effects of the use of Probefix.

Conclusions

In this small feasibility study, the Probefix could be used in eight out of ten intensive care patients. The use of Probefix did not result in more or less accurate CO measurements compared to manually recorded TTE CO measurements. We suggest that larger studies on the use of Probefix in intensive care patients are needed.

Point-of-care Ultrasound (PoCUS) for the internist in Acute Medicine: a uniform curriculum

The use of Point-of-care Ultrasound (PoCUS) is rapidly increasing in internal medicine as it is useful in the primary assessment of acutely ill internal medicine patients for enhanced diagnostics and resuscitation. PoCUS can be taught in a modular fashion including basic core applications and advanced applications which can be combined for a symptom-based approach. Several PoCUS curriculum guidelines, especially for emergency medicine, exist throughout the world but a clear Dutch guideline for internists has not been developed. In this review we propose 'core' ultrasound competencies for internists that may also be incorporated into the European Training Requirements Internal Medicine. We suggest the use of an Entrustable Professional Activities (EPA) competencybased training system with EPAs specifically designed for ultrasound.

[Metformin-associated lactic acidosis: an insufficiently recognised problem]

Metformin-associated lactic acidosis (MALA) is a rare but potentially fatal condition that can easily be avoided. As metformin is known to facilitate the production of lactate, predisposing factors can accelerate this process. In situations of infection or dehydration, metformin can accumulate due to kidney failure, hereby increasing the risk of MALA. Despite controversy in the literature about the presence of a relationship between metformin and lactic acidosis, the severity of the condition is cause for concern and allows for preventive measurements. Awareness of this condition among patients and clinicians is insufficient, resulting in many patients continuing metformin in situations where there is an increased risk of developing MALA. Metformin can easily be discontinued temporarily without causing any harm. We emphasize the importance of temporarily discontinuing metformin in situations where the risk of lactic acidosis is increased, such as severe infection, dehydration and acute kidney insufficiency. This requires increased awareness and adequate counselling by clinicians as well as pharmacists.

A case of extreme hypokalaemia

Hypokalaemia is a common clinical problem. It can lead to severe disturbances in cardiac, neurological and muscle function. We present the case of a 45-year-old woman who was transported to our hospital with cardiac arrest following ventricular fibrillation. Blood sampling revealed severe acidosis (pH 7.02) and extreme hypokalaemia (0.9 mmol/l). The low serum potassium level was most likely caused by the combination of a very deficient diet and use of a thiazide diuretic. She never reported any symptoms. An acute intracellular shift of potassium due to epinephrine and perhaps also the cathecholamines in Red Bull may have further decreased the serum potassium concentration. To our knowledge, this is the lowest potassium level reported in literature. Longer-lasting hypokalaemia might be asymptomatic but when combined with even minor triggers of acute hypokalaemia, serious morbidity or mortality can suddenly occur. Patients on diuretic treatment with suspected malnutrition or chronic gastrointestinal losses require regular monitoring of electrolytes.

The use of ultrasound during and after central venous catheter insertion versus conventional chest X-ray after insertion of a central venous catheter

BACKGROUND

After insertion of a central venous catheter (CVC) a conventional chest X-ray (CXR) is usually taken to check for complications and correct position. Ultrasound might be equally effective as CXR and is less time consuming. We studied the use of ultrasound versus CXR after insertion of a CVC in general ward patients.

METHODS

General ward patients in need of a CVC were included. CVCs were inserted under direct ultrasound guidance. After insertion, ultrasound was performed and compared with CXR to check for complications and position. The waiting time for CXR was noted.

RESULTS

In total, 53 patients were included. In 52/53 patients ultrasound was feasible. The results of ultrasound and CXR only differed in 3 of 53 patients. The sensitivity of ultrasound in detecting the correct CVC position was 98% (89.4-100%). No complications were detected (ultrasound or CXR). The median waiting time for CXR was 24.5 minutes.

CONCLUSIONS

Our study shows that an integral use of ultrasound during and after CVC insertion is effective in establishing that the CVC is correctly positioned and for identifying post-procedural complications in patients from the general ward when compared with CXR.

Binary ultrasonography for the internist: yes or no, that’s the question!

The authors discuss the pros and cons with regard to ultrasound for the internist. They state that ultrasonography is seldom used by internists and they suggest several reasons for this. After a brief review of the literature they conclude that using ultrasound would probably benefit patients and would lead to a more rapid diagnosis and an increase in safety while performing invasive diagnostic and therapeutic interventions. The authors suggest that internists use ultrasound in a different way compared with radiologists, cardiologists, etc. They introduce the term binary ultrasound: ultrasound should be used to answer clinical questions with a yes or a no.

Metabolic acidosis improves airway conductance in patients with asthma

The objective was to investigate whether acute metabolic acidosis could cause bronchodilation in patients with asthma. Twelve patients with asthma (8 females, mean age 39 (+/- SD 12) years, forced expiratory volume in 1 second [FEV(1)] 93 [+/-9] % predicted, PC(20) 1.9 (+/-1.0) mg/mL) participated in a double-blind, placebo-controlled trial. Subjects ingested calculated amounts of ammonium chloride to induce acidosis or saline as placebo, in random order, each on a separate day. Airway resistance (R(aw)), specific airway conductance (sG(aw)), FEV(1), and PEF were measured as primary variables. To evaluate the consequences of alterations in bronchial contractility on the airway responsiveness, the histamine provocation test (PC(20)) was measured as secondary variable. The intervention resulted in a mean (SD) decrease in base excess from -0.5 (+/-1.4) to -3.9 (+/-1.1) mmol/L (p < 0.01) and a decrease in pH from 7.41 (+/-0.02) to 7.36 (+/-0.02) (p < 0.01). This caused a statistically significant increase in sG(aw) from 1.15 (+/-0.16) to 1.26 (+/-0.13) 1/kPa.s) (p < 0.05). Tendencies towards increase were found in PEF (7.79 (+/-2.2) versus 8.09 (+/-1.9) (NS, p = 0.10) and in FEV(1) (2.98 (+/-0.9) versus 3.06 (+/-0.9) (NS, p = 0.15). PC(20) did not change significantly. It was concluded that acute metabolic acidosis has a modest bronchodilating effect in patients with asthma.

Decontamination of the digestive tract and oropharynx in ICU patients

BACKGROUND

Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting.

METHODS

We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance.

RESULTS

A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively.

CONCLUSIONS

In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)

[Serious and sometimes fatal consequences of high-altitude pulmonary oedema]

Three women aged 25, 34 and 22 years respectively, experienced high-altitude pulmonary oedema during a climbing holiday. The first patient presented with complaints arising from a fast ascent to high altitude and was treated with acetazolamide and rapid descent. She recovered without any complications. The second patient developed symptoms during the night, which were not recognised as high-altitude pulmonary oedema. The next morning she died while being transported down on a stretcher without having received any medication or oxygen. The third case was not a specific presentation of high-altitude pulmonary oedema but autopsy revealed pulmonary oedema. This woman had already been higher up on the mountain before she developed complications. The cases illustrate the seriousness of this avoidable form of high altitude illness. The current Dutch national guidelines advise against the use of medication by lay people. A revision is warranted: travellers to high altitude should be encouraged to carry acetazolamide, nifedipine and corticosteroids on the trip. Travel guides ought to be trained to use these drugs. In addition climbing travellers should be encouraged to adopt appropriate preventive behaviour and to start descending as soon as signs of high-altitude pulmonary oedema develop.

Reality of severe metformin-induced lactic acidosis in the absence of chronic renal impairment

BACKGROUND

Lactic acidosis in metformin use is a widely recognised but rare side effect. Case reports usually describe elderly patients with conditions which in themselves can cause lactic acidosis or with known contraindications to metformin. We present cases of an elderly woman, a younger woman and a man who developed serious metformin-induced lactic acidosis in the absence of chronic renal impairment.

RESULTS

Laboratory results showed acute renal failure in all patients. The pH was 6.77, 6.98 and 6.7, respectively, and lactate levels were 18.2, 18.4 and 11.7 mmol/l, respectively. Metformin plasma levels were 58, 57 and 39 mg/l. All patients received continuous veno-venous haemofiltration (CVVH), using bicarbonate as a buffer solution shortly after arrival on our ICU. In the subsequent hours, a steep decline in the plasma levels was observed, with a concomitant increase in pH. No other diagnoses were made, so we concluded that all patients were suffering from metformin-induced lactic acidosis. Despite the severity of the metabolic acidosis, both female patients survived. Our male patient died after a prolonged stay in the ICU, but this was not related to metformin.

CONCLUSION

Metformin-induced lactic acidosis does exist. Metformin-induced lactic acidosis may occur in patients with previously normal renal function, even in young patients. Patients with extreme (lactic) metabolic acidosis caused by metformin can survive when CVVH treatment is initiated rapidly. Intercurrent symptoms or diseases that affect renal perfusion can precipitate lactic acidosis.

The red cell revisited--matters of life and death

An erythrocyte-fractionating method combining volume and subsequent density separation is described. Iron isotope (59Fe)-validation proved this combination of methods to be complementary. By deploying HbA1c as cell age marker, obtained fractions demonstrated that circulating erythrocytes lose 20% of hemoglobin and membrane by shedding vesicles. Vesiculation from older cells proved to be facilitated by the spleen. Animal studies revealed that such vesicles are rapidly removed from the circulation by scavenger receptors on Kupffer cells with phosphatidylserine acting as the principal ligand. These studies reveal the existence of an alternative pathway of erythrocyte breakdown. This means that the premortal substrate of 20% of any erythrocyte is at our disposal. As this kind of vesiculation takes place during the entire erythrocyte lifespan, loss and sometimes reutilisation of marker substances limits the usefulness of isotope studies to the first half of the erythrocyte lifespan, thereby putting the dogmatic lifespan of 120 days into question. Furthermore, these studies add to the understanding of hemoglobin A1c (HbA1c) metabolism and the origin of the wide variation of erythrocyte parameters in peripheral blood. Removal of old erythrocytes from the circulation and from donor blood may open new ways into the treatment of both bilirubin and secondary iron overload.

Stepwise sedation is safe and effective for the insertion of central venous catheters

BACKGROUND

The introduction of a central venous catheter in haemodialysis patients is an unpleasant procedure for the patient. Intravenous sedation is accepted practice in complicated endoscopic procedures but not often used in haemodialysis patients.

METHODS

We developed a protocol for the use of stepwise sedation in these patients with the use of midazolam and fentanyl.

RESULTS

Stepwise sedation with midazolam and fentanyl was used in 155 procedures. No or minor movements were observed in 94% of 154 procedures. 88% of the 155 procedures were graded as very easy or easy. No or only very slight recall of the procedure were noted in 86% of 133 procedures. Only in 7% of 132 procedures were the patients able to recollect most of the procedure. No, or only a small amount of pain was recollected in 93% of 131 procedures. The most important complication was a slight decrease in oxygen saturation in 23 procedures. In the second part of the study we compared the effects of sedation with midazolam alone versus the combination of midazolam and fentanyl for the introduction of Tesio catheters. Amnesia, ease of procedure and the recollection of pain were equivalent. Oxygen desaturation occurred significantly less often with the use of midazolam alone.

CONCLUSION

We conclude that stepwise sedation is effective and safe in haemodialysis patients and leads to a complete amnesia for the procedure.

Culture negative endocarditis combined with glomerulonephritis caused by Bartonella species in two immunocompetent adults

Two cases of culture negative endocarditis are presented. In both, Bartonella species could be identified as the causative agent and in one of them Bartonella henselae was very likely. Both cases were accompanied by glomerulonephritis, in one case proven by a kidney biopsy. A nephrotic syndrome may be the first presentation of an endocarditis caused by Bartonella species.

Effects of peritoneal dialysis with an overnight icodextrin dwell on parameters of glucose and lipid metabolism

OBJECTIVE

To examine whether a reduced daily glucose load by overnight application of the less-absorbed glucose polymer icodextrin would have favorable effects on lipid profiles of continuous ambulatory peritoneal dialysis (CAPD) patients.

STUDY DESIGN

Randomized crossover study with two subsequent periods of 6 weeks.

SETTING

Home PD unit of a secondary-care hospital.

PATIENTS

Twenty-one nondiabetic CAPD patients (15 male, 6 female; mean age 50.3+/-11.8 years).

INTERVENTION

Participants were randomly assigned to receive an overnight dwell with either standard glucose solution or with a 7.5% icodextrin-containing solution.

MAIN OUTCOME MEASURES

Relation between reduction in the total amount of intraperitoneal infused glucose and parameters of glucose (plasma glucose, insulin, and HbA1C) and lipid metabolism [free fatty acids, plasma lipids, lipoproteins, and low density lipoprotein (LDL) subfraction profile].

RESULTS

After the icodextrin dwells, a reduction of plasma total cholesterol (from 5.43+/-0.85 to 4.86+/-0.70 mmol/L, p < 0.001) and LDL cholesterol (from 3.38+/-0.87 to 2.93+/-0.73 mmol/L, p = 0.001) was observed. Also, high density lipoprotein (HDL) cholesterol (from 0.95+/-0.27 to 0.90+/-0.24 mmol/L, p = 0.029) was reduced, but the plasma total cholesterol-to-HDL ratio remained similar. Plasma free fatty acids and triglyceride levels tended to decrease (from 0.16+/-0.10 to 0.13+/-0.08 mmol/L, p= 0.06, and from 2.14+/-1.96 to 1.92+/-1.03 mmol/L, respectively). Evaluation of LDL subfraction profiles after ultracentrifugation showed a more buoyant LDL subfraction profile with fewer dense LDL particles in 6 patients and no changes in 14 patients after icodextrin. The effects on lipids were not accompanied by a decrease in fasting plasma glucose (from 5.76+/-1.29 to 5.86+/-0.80 mmol/L) or insulin levels (from 19.5+/-14.4 to 20.3+/-13.0 mU/L).

CONCLUSION

These results suggest a beneficial effect on lipid profiles of CAPD patients with the use of an overnight dwell with icodextrin.

Effect of acute metabolic acid/base shifts on the human airway calibre

Acute metabolic alkalosis (NaHCO(3)), acidosis (NH(4)Cl), and placebo (NaCl) were induced in 15 healthy volunteers (12 females, median age 34 (range 24-56) years) in a double blind, placebo controlled study to evaluate the presence of the effects on airway calibre. Acid-base shifts were determined by capillary blood gas sampling. Measurements were performed at the maximal acid-base shift, 90 min after intervention. Airway resistance (R(aw)) and specific airway conductance (sG(aw)), were evaluated, as primary variables, pre and post intervention. Secondary variables, including bronchial responsiveness to histamine, maximal respiratory mouth pressures and grip strength, were evaluated post intervention. In alkalosis, base excess (BE) increased from -0.3 (-3.0-1.9) to 3.0 (1.0-4.8) mmol/l and pH increased from 7.41 (7.37-7.43) to 7.44 (7.39-7.47) (both P<0.01), accompanied by an increase in Pa(CO(2)): 4.7 (4.0-5.7) to 5.0 (4.7-6.1) kPa (P<0.05). R(aw) increased from 0.156 (0.134-0.263) to 0.169 (0.132-0.271) kPa s/L (P<0.05), sG(aw) decreased, but this was not statistically significantly. In acidosis, BE decreased from -0.2 (-2.0-2.2) to -3.5 (-6.3-1.1) mmol/l and pH decreased from 7.41 (7.39-7.45) to 7.36 (7.31-7.40) (both P<0.01), accompanied by a non-significant decrease in Pa(CO(2)). Changes in R(aw) and sG(aw) were contrary to those in alkalosis, but did not reach statistical significance. Acute metabolic acid-base shifts mildly influence the airway calibre in healthy human subjects.

[Acute renal insufficiency due to vomiting or diarrhea: the Achilles heel of medical support for heart failure]

Morbidity and mortality of heartfailure are decreasing because of improved medical treatment. The recompensation balance can however be very fragile, which is illustrated by three patients. A woman aged 73 and a man aged 62, both known with heart failure, became seriously ill after diarrhoea; examination revealed uraemia, hyperpotassaemia and raised digitalis levels. A man aged 72, also with heart failure and diarrhoea, developed sensory disorders in both feet. He, also, was found to suffer from renal insufficiency. All patients used an angiotensin converting enzyme inhibitor or an angiotensin-II-antagonist and an aldosterone receptor blocker as well. During the (innocent) intercurrent disease by which their intravascular volume diminished they developed a severe renal insufficiency which needed clinical, intensive treatment. After haemodialysis, all three recovered well. Renal function plays an essential role in the fragile treatment balance that exists in recompensated cardiac patients. The medication that is beneficial for the cardiac functioning may at the same time compromise the renal perfusion. Good monitoring and good instructions about what to do in case of intercurrent diseases are of vital importance in these patients.

Oral bioavailability of phenobarbital: a comparison of a solution in Myvacet 9-08, a suspension, and a tablet

PURPOSE

A three-way crossover study with seven healthy male volunteers was conducted to determine the relative bioavailability of phenobarbital after single dose administration of 100 mg of phenobarbital as oral solution in Myvacet 9-08, and as a suspension, compared with a 100 mg phenobarbital tablet.

MATERIALS AND METHODS

At 4-week intervals each subject received the solution in Myvacet 9-08, the suspension and the tablet in randomized order. Blood samples were collected for 48 h after each dose for analysis of phenobarbital. From the individual serum concentration-versus-time curves Cmax and Tmax were determined and AUC0-48 was calculated.

RESULTS

All three oral dosage forms of phenobarbital are bioequivalent. No significant differences in Tmax were observed.

CONCLUSION

The oral solution in Myvacet 9-08, and the suspension of phenobarbital proved to be bioequivalent to a tablet.

Volumetric measurements of peripheral oedema in clinical conditions

Water-displacement volumetry can be used for quantifying the volume of the leg. However, not much is known about its application in patients with peripheral oedema of cardiopulmonary origin. We measured the reproducibility of a water-displacement apparatus with a solid object and in ten non-oedematous clinical patients (group A). The day-to-day variability of the leg volume was assessed in the same group. The diurnal variability was assessed in ten patients with persisting peripheral oedema (group B). The effect of treatment on the severity of peripheral oedema was evaluated in another nine patients with peripheral oedema, who were in need of diuretic treatment (group C). Volumetric results were compared to the ankle circumference method and the body weight method. The coefficient of variation was 0.16% in the fixed object and 0.47% in group A. The day-to-day variability was 1.52% after 1 day and 1.76% after a mean interval of 4.8 days. In group B, leg volume and circumference increased during the day (5.9%, P<0.001, and 2.4%, P<0.01, respectively), while body weight remained unchanged. In group C, leg volume, circumference and body weight decreased significantly after treatment (13.1%, P<0.01, 7.1%, P<0.05, and 5.9%, P<0.05). The correlation between the changes in volume and body weight was poor (r=0.37, P=0.33). In conclusion, (1) water-displacement volumetry is highly reproducible, (2) a diurnal variability of peripheral oedema was found, and (3) volumetry is a suitable tool for monitoring peripheral oedema, while the body weight method appears to be less accurate.

[Use of noninvasive mechanical ventilation to avoid intubation during acute respiratory insufficiency]

OBJECTIVE

To determine the value of noninvasive mechanical ventilation in patients with acute respiratory insufficiency.

DESIGN

Descriptive.

METHODS

Noninvasive mechanical ventilation was considered in all patients with acute respiratory insufficiency in the intensive care unit of the Rijnstate Hospital, Arnhem, the Netherlands, between 1 June 1998 and 31 January 1999. Indication for mechanical ventilation was: respiratory frequency > or = 28/min, and PaCO2 > 6.0 kPa, pH < 7.35, and/or PaO2 < 8.0 kPa. Patients were intubated immediately in case of systolic blood pressure < 90 mmHg, cardiac or respiratory arrest, coma or a severely diminished consciousness. The other patients received noninvasive mechanical ventilation by nasal or full face mask (pressure support: 10-20 cmH2O; positive end expiratory pressure (PEEP): 0-5 cmH2O). Patients were intubated if the respiratory frequency or the level of consciousness or a blood gas value deteriorated.

RESULTS

Of the 97 patients who needed ventilation support, 67 were immediately intubated. Noninvasive mechanical ventilation was administered in the other 30 (31%) patients, 22 men and 8 women with a mean age of 67 years (SD: 15). Causes for acute respiratory failure were: chronic obstructive pulmonary disease (COPD) (n = 12); pneumonia (n = 6); heart failure (n = 4); and other (n = 8). Median characteristics at baseline in the noninvasive mechanical ventilation group: acute physiology and chronic health evaluation (APACHE) II score: 17 (range: 1-25); respiratory frequency: 30/min (28-59); pH: 7.33 (6.99-7.54); PaCO2: 9.3 kPa (3.2-18.7); PaO2: 7.4 kPa (4.2-13.4); SaO2: 85% (63-95). Intubation was avoided in 9/30 (30%) of all patients and in 7/12 (58%) of the patients with COPD. Intubation was needed in 21/30 patients (70%): in 8/30 (27%) immediately because of clinical deterioration within 2 hours and in 13/30 (43%) after a mean period of stabilisation of 6 hours (2-16).

CONCLUSION

Noninvasive mechanical ventilation prevented intubation in over half of the selected patients presenting with acute respiratory failure due to an exacerbation of COPD. The method appears to be less successful in acute respiratory failure due to other causes.

[Open lung biopsy in severely ill patients with unrecognized pulmonary infiltrates]

In three patients, a man aged 34 with aids, a woman aged 67 with recurrent major dyspnoea and a woman aged 73 with chronic lymphatic leukaemia, examination revealed progressive dyspnoea while the chest X-rays showed infiltrative lesions in both lungs. In view of the inadequate response to the treatment administered, an open lung biopsy was performed, following which the diagnosis could be made. Adequate treatment was then started and followed by clinical recovery. It is not clear if open lung biopsy carries higher risks of mortality and morbidity than biopsy by means of flexible bronchoscopy. Open lung biopsy more often leads to a classifying diagnosis. For collection of endobronchial or transbronchial biopsy samples in ununderstood diffuse interstitial lung diseases, flexible bronchoscopy is the method of first choice. Open lung biopsy is a justified supplementary examination, at any rate in severely ill, immunocompromised patients who require adequate therapy without delay.

Cerebral hemorrhage complicating exertional heat stroke

Exertional heat stroke may be complicated by mild neurological deficits, usually with complete convalescence. This may be associated with metabolic disorders inherent to hyperthermia such as a marked coagulopathy. We report a case of a previously healthy 20 year old male who died in the course of exertional heat stroke complicated by intracerebral hemorrhage.

[Clinical reasoning and decision making in the practice. A woman with abdominal complaints]

A female patient aged 28 years suffered from recurrent episodes of diarrhoea. Giardia lamblia was isolated once. By rigorous application of basic clinical skills, such as thorough history taking and physical examination, together with laboratory tests the correct diagnosis was established (in this patient systemic lupus erythematosus). Two important aspects of clinical reasoning, viz. returning to the patient when new information becomes available (cyclic way of working) and pattern recognition ensured a fruitful diagnostic process.

[Percutaneous jugular Tesio catheter useful for long-term hemodialysis: experiences in 26 patients]

OBJECTIVE

Inventory of the Tesio catheter (TC), its functioning and complications.

DESIGN

Retrospective descriptive file investigation.

SETTING

Rijnstate Hospital, Arnhem, the Netherlands.

METHOD

From the hospital files of the patients with chronic renal insufficiency who from July 1992 until October 1995 received a TC, we collected data on indications for placing and removing, duration, complications of the TC and mortality.

RESULTS

Data were suitable for 26 patients, 8 men and 18 women, mean age 63 year (range: 33-79). The indications proved to be short life expectancy, failure of other vascular access and expected long catheter dialysis. The total number of days the TC was in situ was 2780 (median: 80.5: range: 15-559). Fourteen patients showed no complications, one patient had dysfunction of the TC due to thrombosis, local infection occurred around the insertion opening in five and bacteremia in seven patients. In one patient, with a prosthetic cardiac valve, the catheter had to be removed prematurely because of an infection. No deaths due to the TC occurred.

CONCLUSION

The TC appears to be a safe form for long-term haemodialysis.

Quantification of loss of haemoglobin components from the circulating red blood cell in vivo

Previous studies have shown that a considerable amount of haemoglobin is lost from the intact red cell during its lifespan. The aim of this study was to determine the relative contribution of all the haemoglobin components to this process. Therefore, the relative amount of haemoglobins A0, A2, F and the glycated haemoglobins were determined in 24 fractions of different cell age. These fractions were obtained by the combination of counterflow and density centrifugation. When the absolute amount of all haemoglobin components were calculated using the MCH-values of each fraction, it appeared that the mean red cell loss of haemoglobins A0, A2, F, an unknown X and "rest" comprised, respectively, 440, 23, 1, 4 and 1 amol per cell, while the mean gain of the glycated haemoglobins was 84 amol per cell. This resulted in a net loss of 385 amol of haemoglobin per cell. One of the glycated haemoglobins (HbA1e2) turned out to be the product of further carbamylation. It was concluded that in the first half of the red cell lifespan HbA0 and HbA2 decreased by glycation and carbamylation and that in the second half some of the HbA0 and HbA2 but also some of the glycated and carbamylated haemoglobin components leave the red cell. The total loss amounted to about 20%.

The incidence of subclavian vein stenosis using silicone catheters for hemodialysis

Complications related to the use of silicone subclavian catheters for hemodialysis were prospectively studied in 21 consecutive patients with acute and chronic renal failure. Between July 1991 and December 1992, 34 double-lumen silicone catheters (Medcomp; 12 French; 20 or 24 cm) were inserted in 21 patients. The mean duration of catheterization was 20 days (range, 2-58 days). Venograms were performed in 16 patients (22 subclavian veins) within 6 months following removal of the catheter. Excluded from angiography were patients whose catheters had been in place less than 1 week or who underwent fewer than 3 dialysis sessions because of minor risk of stenosis. Patients who had ipsilateral repeated catheters were also excluded. Two angiographies showed subclavian vein stenosis, both occurring in the same patient. One showed 50% stenosis with collaterals; one showed 50% stenosis without collaterals. One other complication was a pneumothorax. Catheter thrombosis was observed in 3 patients; catheter sepsis did not occur. We conclude that use of silicone catheters for subclavian cannulation is safe and effective to provide temporary vascular access for acute hemodialysis. The incidence of subclavian vein stenosis is lower compared with polytetrafluoroethylene and polyurethane catheters.

Vascular access in continuous arteriovenous hemodiafiltration

We describe experiences with the use of silicone catheters for continuous arteriovenous hemodiafiltration (CAVHD) in 43 patients in the Intensive Care Unit from July 1991 through March 1993. There were no serious complications with regard to the use of these widebore catheters at introduction, during therapy, or at removal. All patients who needed renal replacement therapy could be treated with CAVHD. This low complication rate is probably due to a very strict CAVHD protocol and the fact that only a few people supervise this therapy.

[Successful electroconvulsive therapy in a pregnant woman with neuroleptic malignant syndrome]

Neuroleptic malignant syndrome was diagnosed in a 27-year-old pregnant female with a psychiatric disorder, after treatment with haloperidol. The syndrome did not respond to treatment with dantrolene. Serious vegetative instability weighed against the use of electroconvulsive treatment. After 29 3/7 weeks of amenorrhoea electroconvulsive treatment was started, and the clinical picture gradually improved. Mother and child were discharged in good clinical condition.

Determinants of red blood cell deformability in relation to cell age

Red blood cell (RBC) deformability was determined with an ektacytometer in fractions separated on the basis of differences in cell volume or density. Deformability was measured with ektacytometry (rpm-scan and osmo-scan). We studied three groups of RBC fractions:1. By counterflow centrifugation we obtained fractions of different cell age which showed a slight decrease in mean corpuscular haemoglobin concentration (MCHC) and an increase in surface-to-volume (S/V) ratio in fractions with older cells. 2. By Percoll fractionation fractions were obtained which showed a pronounced increase in (MCHC) but no change in S/V ratio. 3. By a combination of both fractionation techniques, fractions were obtained which showed an increased MCHC and an increase in S/V ratio. Deformability in group 1,2 and 3 showed respectively no change, a moderate decrease and a pronounced decrease in fractions of older cells. A decline in deformability occurs during the aging process of the red blood cell. This decline in deformability in old red cells is greater than originally thought. This decline is the result of an increase in haemoglobin concentration and a second factor, probably a decrease in membrane elasticity.

Effects of hypoxia and atrial natriuretic peptide on aldosterone secretion in healthy subjects

To evaluate the inhibitory effect of hypoxia and atrial natriuretic peptide (ANP) on aldosterone secretion, 11 healthy male subjects were infused with 5 ng.kg-1 x min-1 ANP or placebo. The subjects were exposed in a stepwise fashion to incremental hypobaric hypoxia, which decreased arterial oxygen saturation to 79 +/- 2% in the placebo and 84 +/- 2% in the ANP condition (P < 0.05). In the placebo condition, the plasma ANP concentration increased from 13.8 +/- 1.0 to 19.6 +/- 2.3 pmol/l (P < 0.01) at the lowest barometric pressure. Plasma renin activity did not change, whereas the plasma aldosterone levels increased consequent to the increase of plasma adrenocorticotropic hormone (ACTH). Continuous infusion of ANP increased the plasma levels twofold (P < 0.001) and the level of guanosine 3',5'-cyclic monophosphate threefold (P < 0.001). However, the plasma aldosterone concentrations were not different in the two experimental conditions. Administration of supplementary oxygen significantly decreased ACTH to baseline values (P < 0.01) together with a decrease in aldosterone. Free water clearance (P = 0.05) but not sodium excretion (P = NS) increased during continuous ANP infusion. The data indicate that the aldosterone secretion in hypoxia is not inhibited by (patho)physiological plasma ANP levels. The inhibition of aldosterone secretion may well be explained by a direct effect of hypoxia on the adrenal cells. ACTH is a major stimulus of aldosterone secretion in hypoxia, which overrides the natriuretic effect of ANP.

[Surgical complications in treatment with continent ambulatory peritoneal dialysis; 9-year experience]

OBJECTIVE

To determine the number of surgical complications in patients treated with continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

Retrospective (1980-1989), partially prospective (1987-1989).

SETTING

Rijnstate Hospital, Arnhem, the Netherlands.

METHOD

In 1978 CAPD was introduced in the Netherlands. Since 1980 we have used this technique in our clinic. Over the period 1980-1989 we studied the number of surgical complications of CAPD and the loss of catheter caused by these complications. With these numbers the probability of having a functioning Tenckhoff double cuff catheter was calculated with the Kaplan-Meier method.

RESULTS

101 patients (54 men (mean age 52.5 years), 47 women (mean age 49.6 years)) with terminal renal insufficiency were treated during the study period. 123 catheters were implanted of which 33 had to be removed afterwards. The probability of having a functioning catheter after one year was 85%, after two years 64% and after three years 53%. Peritonitis was the main cause of temporary or final loss of the catheter. The number of observed cases of peritonitis was 187.

CONCLUSION

Methods to improve the survival of the catheter are prevention of peritonitis by using an appropriate system for the fluid exchanges, screening patients for the existence of diverticulosis before starting CAPD, and prevention of exit site and tunnel infections.

[9-year experience with continuous ambulatory peritoneal dialysis in one center]

The experience gained with CAPD in a group of 101 patients with terminal renal failure and a subgroup of 19 patients with diabetes mellitus was analysed. The actuarial patient survival was 81% after two years and 50% after five years. The combined patient-technique survival after two years was 48.8%. The most important reasons for drop-out were transplantation (25%) and death (24%). Death was method-related in 4 patients and caused by peritonitis in 2 of them. More often peritonitis was the cause of morbidity and temporary interruption (10 x) or of permanent abandoning of the method (11 x ). The peritonitis frequency during the whole period of nine years was 1 : 11.3 months. Use of the Y-connector Twinbag system and a U.V.-light system reduced the incidence substantially. However, faecal peritonitis remains a dangerous situation which cannot be prevented in this way. The mortality in patients with diabetes mellitus is high but not method-related. The incidence of peritonitis is not significantly different from that among patients without diabetes mellitus.

[Experience with continuous arteriovenous hemodiafiltration for acute kidney insufficiency in intensive care patients]

Acute renal failure is a frequent complication at the Intensive Care Department. For this complication dialysis is often necessary. In our Intensive Care Department we have opted for continuous arteriovenous hemodiafiltration (CAVHD) as the treatment of first choice for patients with acute renal failure. We describe the results in 18 patients treated with CAVHD. In all patients an arterious and a venous catheter were placed, in most cases in the femoral artery and vein. A capillary hemofilter was placed between the catheters. In the filter a counterflow mechanism took place. All patients were successfully treated with CAVHD. Haemodynamic instability as an effect of the treatment did not appear. The fluid and electrolyte balance was perfectly under control. Renal function was recovered in 7 patients. Twelve patients died. The cause of death was never associated with the renal failure or with the CAVHD treatment.