Wearable pulmonary monitoring system with integrated functional lung imaging and chest sound recording: a clinical investigation in healthy subjects.

Objective.Current wearable respiratory monitoring devices provide a basic assessment of the breathing pattern of the examined subjects. More complex monitoring is needed for healthcare applications in patients with lung diseases. A multi-sensor vest allowing continuous lung imaging by electrical impedance tomography (EIT) and auscultation at six chest locations was developed for such advanced application. The aims of our study were to determine the vest's capacity to record the intended bio-signals, its safety and the comfort of wearing in a first clinical investigation in healthy adult subjects.Approach.Twenty subjects (age range: 23-65 years) were studied while wearing the vests during a 14-step study protocol comprising phases of quiet and deep breathing, slow and forced full expiration manoeuvres, coughing, breath-holding in seated and three horizontal postures. EIT, chest sound and accelerometer signals were streamed to a tablet using a dedicated application and uploaded to a back-end server. The subjects filled in a questionnaire on the vest properties using a Likert scale.Main results.All subjects completed the full protocol. Good to excellent EIT waveforms and functional EIT images were obtained in 89% of the subjects. Breathing pattern and posture dependent changes in ventilation distribution were properly detected by EIT. Chest sounds were recorded in all subjects. Detection of audible heart sounds was feasible in 44%-67% of the subjects, depending on the sensor location. Accelerometry correctly identified the posture in all subjects. The vests were safe and their properties positively rated, thermal and tactile properties achieved the highest scores.Significance.The functionality and safety of the studied wearable multi-sensor vest and the high level of its acceptance by the study participants were confirmed. Availability of personalized vests might further advance its performance by improving the sensor-skin contact.

Electromagnetic disturbances rejection with single skin contact in the context of ECG measurements with cooperative sensors.

Classical approaches to make high-quality measurements of biopotential signals require the use of shielded or multi-wire cables connecting the electrodes to a central unit in a star arrangement. Consequently, increasing the number of leads increases cabling and connector complexity which is not only limiting patient comfort but also anticipated as the main limiting factor for future miniaturization and cost reduction of tomorrow's wearables. We have recently introduced a novel sensing architecture that significantly reduces cabling complexity by eliminating shielded or multi-wire cables as well as by allowing simple connectors thanks to a bus arrangement. In this architecture, electrodes are replaced by so-called cooperative sensors. However, in this design, one of the cooperative sensors needs to be equipped with two contacts with the skin for proper common mode rejection, thus making its miniaturization problematic. This paper presents a novel common mode rejection principle which overcomes this limitation. When compared to others, the suggested approach is advantageous as it keeps the cabling complexity to its minimum. First measurements demonstrated in a real-life scenario the feasibility of this common mode rejection principle for a wearable 12-lead electrocardiogram monitoring system.

Fatal nonmeningitic Listeria rhombencephalitis. Report of two cases.

Two cases of rapidly fatal Listeria rhombencephalitis with normal cerebrospinal fluid (CSF) findings occurred in previously healthy adults. The infection presented with nausea and headache followed by fever and signs of lower cranial nerve dysfunction, without associated meningismus, and progressed to death within four and six days of hospitalization. Because of normal CSF findings (including ventricular fluid in one patient) and negative culture results of both blood and CSF, the diagnosis was not suspected. Listeriosis should be considered early in any febrile patient presenting with signs of brain-stem dysfunction, even if CSF findings are normal.

Diagnosis of central venous catheter-related sepsis. Critical level of quantitative tip cultures.

The results of a simplified quantitative broth dilution quantitative tip culture (QTC) of 331 central venous catheters were compared with clinical data prospectively recorded in critically III patients to diagnose bacteremic or nonbacteremic catheter-related sepsis (CRS) (36 catheters), as opposed to contamination (42 catheters) or simple colonization from a distant septic focus (seven catheters). Thirty-five of 36 catheters associated with CRS yielded 10(3) colony-forming units per milliliter (CFU/mL) or more, and 3.8 X 10(2) Candida organisms grew from one. In contrast, 5 X 10(2) CFU/mL or less grew from 37 of 42 contaminated catheters. A QTC of 10(3) CFU/mL or more was 97.5% sensitive and 88% specific for the diagnosis of CRS. The QTC appeared especially useful for the diagnosis of CRS secondary to blood-borne seeding of catheters, or associated with coagulase-negative staphylococci.

Cooperative dry-electrode sensors for multi-lead biopotential and bioimpedance monitoring.

Cooperative sensors is a novel measurement architecture that allows the acquiring of biopotential signals on patients in a comfortable and easy-to-integrate manner. The novel sensors are defined as cooperative in the sense that at least two of them work in concert to measure a target physiological signal, such as a multi-lead electrocardiogram or a thoracic bioimpedance.This paper starts by analysing the state-of-the-art methods to simultaneously measure biopotential and bioimpedance signals, and justifies why currently (1) passive electrodes require the use of shielded or double-shielded cables, and (2) active electrodes require the use of multi-wired cabled technologies, when aiming at high quality physiological measurements.In order to overcome the limitations of the state-of-the-art, a new method for biopotential and bioimpedance measurement using the cooperative sensor is then presented. The novel architecture allows the acquisition of the aforementioned biosignals without the need of shielded or multi-wire cables by splitting the electronics into separate electronic sensors comprising each of two electrodes, one for voltage measurement and one for current injection. The sensors are directly in contact with the skin and connected together by only one unshielded wire. This new configuration requires one power supply per sensor and all sensors need to be synchronized together to allow them to work in concert.After presenting the working principle of the cooperative sensor architecture, this paper reports first experimental results on the use of the technology when applied to measuring multi-lead ECG signals on patients. Measurements performed on a healthy patient demonstrate the feasibility of using this novel cooperative sensor architecture to measure biopotential signals and compliance with common mode rejection specification accordingly to international standard (IEC 60601-2-47) has also been assessed.By reducing the need of using complex wiring setups, and by eliminating the presence of central recording devices (cooperative sensors directly sense and store the measured biosignals on the site), the depicted novel technology is a candidate to a novel generation of highly-integrated, comfortable and reliable technologies that measure physiological signals in real-life scenarios.

Pulmonary gas exchange during venoarterial bypass with a membrane lung for acute respiratory failure.

In patients with fulminating pulmonary edema not responsive to conventional therapy, venoarterial membrane lung bypass can provide assistance if decreased systemic blood pressure prevents use of high-level positive end-expiratory pressure ventilation. In 10 patients with acute respiratory failure, partial venoarterial bypass provided a rapid and marked improvement of systemic oxygenation. Measurement of pulmonary blood flow (PBF) and intrapulmonary shunting (QS/QP) during bypass via prolonged left heart catheterization showed that left ventricular PaO2 was increased through a rapid and profound reduction of QS/QP. During the first days of bypass, derecruitment of pulmonary vessels is probably the mechanism of improved pulmonary oxygenation. When low pulmonary arterial pressures (PAP) are sustained, resorption of pulmonary edema is favored. Despite the beneficial effects of bypass, death occurred in every case due to diffuse interstitial fibrosis and/or parenchymal damage. The absence of healing, due to prolonged circulatory exclusion, may be detrimental despite immediate improvement. Because of this possibility, venovenous or mixed perfusion should be more extensively explored.

The ethics of intensive care.

An explanation is provided of the logical steps taken before assigning patients to critical care therapy in a major multidisciplinary intensive care unit of the University of Paris at the Hospital Henri Mondor. The factors considered by the staff in deciding to terminate intensive therapy are also enumerated. This system has not been influenced by the major legal pressures found in the United States but has been shaped by more chronic fiscal constraints.

Haemodynamic study of patients with severe sepsis during haemodialysis.

A study was performed in order to observe haemodynamic changes induced by haemodialysis in 14 patients with acute renal failure and severe sepsis. Left ventricular function, as assessed by changes in pulmonary wedge pressure and left ventricular stroke work index through plasma volume expansion, did not change during haemodialysis. Ultrafiltration-induced decreases in cardiac index provoked in 8 patients, with nearly normal initial systemic arteriolar resistance, had adequate and constant increase in their resistance (p less than 0.001), whereas 6 patients with low initial systemic arteriolar resistance did not increase their resistance and had a frequent (9/13 measurements) and significant (p less than 0.001) fall in mean aortic pressure. This abnormality of vascular tone is probably due to severe sepsis and explains why hypotension is a frequent occurrence during haemodialysis in such patients.

Circulating immune complexes in patients with gram negative septic shock.

In order to explain complement components abnormalities observed during septic shock, circulating immune complexes (C.I.C.) were searched for in sera from 34 patients with gram negative sepsis by two different methods: polyethylene glycol precipitation test based on physical properties of C.I.C. and C1q deviation test based on the property of radiolabelled C1q to react with C.I.C. Serum immunoglobulins (IgG, IgA, IgM) and complement components (C1q, C3, C4) levels were simultaneously determined. Seventeen patients with minimal haemodynamic abnormalities had normal or increased levels (except C4 at 62% of normal) and in eleven cases both tests for C.I.C. were simultaneously positive. Seventeen patients with severe septic shock had a decrease in IgG, IgM C1q, C3 and C4 and none had both tests for C.I.C. simultaneously positive (P less than 10(-4)). The disappearence of C.I.C. in patients with severe septic shock associated with evidence of complement activation suggests their involvement in the pathogenesis of septic shock in man.

Hypovolaemic shock with oedema due to increased capillary permeability.

A case of severe hypovolaemic shock related to idiopathic oedema was observed in a 37 year old woman. Large plasma volume expansion (nearly 12 1 over 9 hours) did not change the clinical status. Haemodynamic studies showed low cardiac index (1.1 1/min/m2), decreased left ventricular stroke work index (6.7 gm/m2), and high systemic arterial resistance (52 mmHg/1/min/m2). Dopamine infusion improved the haemodynamic condition which returned to normal 30 hours after the beginning of shock. After recovery, capillary permeability measured by a modification of Landis' method was markedly increased. A study of albumin metabolism showed a normal intravascular pool and a rapid exchange compartment with a twofold increase in slow exchange compartment. Hormonal levels and complement fractions were within normal limits. Serum protein immuno-electrophoresis showed an abnormal IgG. These results clearly demonstrate that hypovolaemia is related to increased capillary permeability and leakage of albumin out of the vascular space. When large infusions fail, inotropic agents, especially Dopamine, should be used in such cases.

Haemodynamic effects of dopamine in septic shock.

The Haemodynamic response to dopamine infusion has been assessed in 30 patients in septic shock with myocardial dysfunction. Dopamine infusion resulted in a haemodynamic improvement as indicated by significant increases in cardiac output of 38.4% (p less than .001), stroke volume 18.7% (p less than .001), and mean arterial pressure of 33% (p less than .001). Despite the inotropic effect, left ventricular filling pressure did not change in 20 cases and increased in 10 cases. Mean peripheral resistance remained unchanged with a scatter of individual responses depending upon factors such as dopamine dose and initial vascular resistance. Dopamine increased intrapulmonary shunting by 48% (p less than .001), insignificantly decreased PaO2, increased mixed venous oxygen saturation by 16% (p less than .02) and decreased pulmonary vascular resistance by 15% (p less than .02). Both isoprenaline and dopamine improve stroke volume by an inotropic action, with an increase in venous return in the case of the latter and a reduction in afterload in the former. It is concluded that the usefulness of dopamine in septic shock may be limited in patients with previous myocardial disease because of the risk of increasing preload and in hypoxaemic patients because of the risk of increasing intrapulmonary shunting.

The role of drug-induced illness in admissions to an intensive care unit.

All patients admitted during a 33-month period to a multidisciplinary intensive care unit were prospectively studied in order to determine the incidence and severity of drug-induced illness leading to the admission. The role of underlying diseases was assessed and the avoidability of drug-induced illness considered. Out of 1651 patients, 97 (5.88%) were admitted because of drug-induced illness; 74 of these had serious underlying diseases. 13 (13.4%) of the 97 patients died, but underlying diseases accounted for 4 of the 13 fatalities. In nearly half of the cases, the drug-induced illness appeared potentially avoidable.

Computed tomography and post-laparotomy intra-abdominal abscesses.

Thirty-one patients were prospectively studied and had abdominal computed tomography for post laparotomy sepsis. Computed tomography is of particular interest in seriously ill post-operative patients, 15 of our patients were on ventilators, and it enabled diagnosis and localization of abscesses in 15 patients. Drainage could therefore be achieved via a limited surgical approach, and extensive laparotomy was avoided. Of 16 patients without abscess, the abdominal computed tomogram was negative in 14 cases and there were two false positives. The overall accuracy was 0.94 with a sensitivity of 1 and a specificity of 0.88. The ability to screen the whole abdomen and exactly localize the lesion are the advantages of this non-invasive method.

Decreased plasma epinephrine concentrations after glucose ingestion in humans.

Plasma levels of norepinephrine (NE), epinephrine (E), immunoreactive insulin (IRI), and glucose were measured in six healthy volunteers after glucose consumption and in six volunteers after a water solution. Ingestion of the glucose (100 g) solution significantly decreased E levels from 46.7 +/- 8.0 to 20.8 +/- 1.9 pg/mL (P less than 0.01). Three hours after the glucose ingestion, plasma E levels nearly returned to basal values. Plasma IRI and glucose levels peaked at 45 minutes after glucose consumption (P less than 0.01), then declined toward basal values. Plasma NE levels were unaffected by glucose consumption. There were no changes in glucose, IRI, NE, or E levels in the control group. These results suggest that E behaves as a counter-regulatory hormone to insulin under stimulation by glucose.

Hemodynamic effects of dopamine in septic shock with and without acute renal failure.

Hemodynamic response to dopamine hydrochloride in septic shock with myocardial dysfunction was studied in ten patients with normal renal function (group 1) and in ten patients with acute renal failure (group 2). The control hemodynamic data were similar in the two groups. Dopamine in groups 1 and 2 induced significant (P less than .01) and similar increases in cardiac index and mean aortic pressure. Group 1 had a smaller increase in heart rate (+ 16%), than group 2 (+ 24%), but this difference was not significant. Stroke volume index had a significant increase in group 1 (+ 18%), whereas it did not increase significantly in group 2 (+ 4%); this difference of changes in stroke volume index between the two groups was significant (P less than .01). This phenomenon suggests an increased chronotropic effect and/or a reduced inotropic effect of dopamine in patients with septic shock and acute renal failure.

Erythromycin pharmacokinetics in man.

This study shows that high serum concentrations are reached after either ethylsuccinate or lactobionate erythromycin administration. But the short elimination half-life implies repetitive administration to obtain efficacy, the ideal being represented by continuous infusion.

[Suppurating splenic infarction originating from endocarditis]. / Infarctus spléniques suppurés d'origine endocarditique.

Three cases of splenic infarction complicated by abscess formation during bacterial endocarditis are reported. In all three cases there were associated clinical abdominal signs and, in one case, there was persistently positive hemocultures. The diagnosis was made by CAT scanning. The three patients underwent splenectomy and one patient also underwent valve replacement the same day. The methods of early diagnosis of splenic complications during endocarditis and the indications of splenectomy are discussed. Ultrasonography and abdominal CAT scanning are the most sensitive diagnostic methods for splenic lesions. As splenic rupture is associated with a high mortality and this complication may occur at any time during infarction complicated by abscess formation, early splenectomy is justified when abdominal clinical signs are elicited associated with a persistent, infectious syndrome with or without positive blood cultures, under appropriate antibiotic therapy. Splenectomy should also be considered if valve replacement is carried out in the same circumstances to avoid infection of the prosthesis.

[Prospective evaluation of the complications of anticoagulants in an intensive care unit]. / Evaluation prospective des accidents des anticoagulants en unité de réanimation.

A prospective study was undertaken in a multidisciplinary intensive care unit to determine the proportion of complications due to anticoagulant therapy, to evaluate their severity and to estimate what proportion was potentially avoidable. Among 1911 hospitalized patients over a 3 year period, 30 patients had a complication of anticoagulant therapy (1,57 p. 100). The causality was definite in 14 cases, probable in 14 and possible in 2 cases. Nineteen p. 100 were hemorrhagic complications. These iatrogenic illnesses were fatal in 5 cases, life-threatening in 6, moderate in 15 and minor in 4 cases. Potentially avoidable complications accounted for 60 p. 100 of the cases and were due to biological overdosage or interaction between drugs. Our results indicate that some complications of anticoagulant therapy could be reduced or eliminated by medical education and increased information.

[Acute adult respiratory distress syndrome after lymphography]. / Syndrome de détresse respiratoire aiguë de l'adulte après lymphographie.

Pulmonary complications of lymphography are usually described as radiological infiltrates without clinical symptoms. However, a case is here reported of an adult respiratory distress syndrome occurring after lymphography in a 60 year old female lymphoma patient. Pulmonary oedema developed within 48 h; haemodynamic study showed a normal capillary wedge pressure. The patient died from intractable low cardiac output within 24 h. Post-mortem examination showed pulmonary lymphocytic infiltration and multiple fat emboli. The lack of lymphatic drainage was probably responsible for the intravascular passage of lipid-soluble contrast medium, this giving endothelial lesions. In such patients with preexisting lung disease or pulmonary involvement in haematological disease, lymphography has to be considered carefully.

[Increase in partial arterial carbon dioxide pressure due to parenteral nutrition during artificial ventilation]. / Augmentation de la pression partielle artérielle en gaz carbonique due à la nutrition entérale au cours de la ventilation artificielle.

The influence of increased enteral caloric intakes on respiratory gas exchanges was evaluated in 6 patients (5 men, 1 woman; mean-age: 54 years) in steady state and requiring continuous ventilatory support. Oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory quotient (R), determined using an open circuit indirect calorimetric method, and arterial blood gases were measured on two consecutive days while ventilation conditions were unchanged. On the first day, the patients received a water diet only and on the following day an enteral caloric load (1491 +/- 65 Kcal/m2/24 h). The results showed a significant increase in VO2 (p less than 0.05) and R (p less than 0.001) and a rise in VCO2 from 106 +/- 4 to 139 +/- 9 ml/mn/m2 (p less than 0.01). The rise in VCO2 induced an increase of arterial carbon dioxide tension (PaCO2) from 26.3 +/- 1.6 to 34.4 +/- 2.4 mmHg (p less than 0.001). This study showed that because of the constancy of alveolar ventilation, the enteral nutrition-related increase of VCO2 is responsible for a PaCO2 increase and emphasized the need for adjusting artificial ventilation to any change in caloric intake in patients supported with mechanical ventilation.