Wrist-Worn Sensor Validation for Heart Rate Variability and Electrodermal Activity Detection in a Stressful Driving Environment

Wearable sensors are widely used to gather psychophysiological data in the laboratory and real-world applications. However, the accuracy of these devices should be carefully assessed. The study focused on testing the accuracy of the Empatica 4 (E4) wristband for the detection of heart rate variability (HRV) and electrodermal activity (EDA) metrics in stress-inducing conditions and growing-risk driving scenarios. Fourteen healthy subjects were recruited for the experimental campaign, where HRV and EDA were recorded over six experimental conditions (Baseline, Video Clip, Scream, No-Risk Driving, Low-Risk Driving, and High-Risk Driving) and by means of two measurement systems: the E4 device and a gold standard system. The overall quality of the E4 data was investigated; agreement and reliability were assessed by performing a Bland-Altman analysis and by computing the Spearman's correlation coefficient. HRV time-domain parameters reported high reliability levels in Baseline (r > 0.72), Video Clip (r > 0.71), and No-Risk Driving (r > 0.67), while HRV frequency domain parameters were sufficient in Baseline (r > 0.58), Video Clip (r > 0.59), No-Risk (r > 0.51), and Low-Risk Driving (r > 0.52). As for the EDA parameters, no correlation was found. Further studies could enhance the HRV and EDA quality through further optimizations of the acquisition protocol and improvement of the processing algorithms.

User Experience during an Immersive Virtual Reality-Based Cognitive Task: A Comparison between Estonian and Italian Older Adults with MCI

Mild cognitive impairment (MCI) is an early stage of cognitive abilities loss and puts older adults at higher risk of developing dementia. Virtual reality (VR) could represent a tool for the early assessment of this pathological condition and for administering cognitive training. This work presents a study evaluating the acceptance and the user experience of an immersive VR application representing a supermarket. As the same application had already been assessed in Italy, we aimed to perform the same study in Estonia in order to compare the outcomes in the two populations. Fifteen older adults with MCI were enrolled in one Rehabilitation Center of Estonia and tried the supermarket once. Afterwards, they were administered questionnaires aimed at evaluating their technology acceptance, sense of presence, and cybersickness. Estonian participants reported low side effects and discrete enjoyment, and a sense of presence. Nonetheless, their intention to use the technology decreased after the experience. The comparison between Italian and Estonian older adults showed that cybersickness was comparable, but technology acceptance and sense of presence were significantly lower in the Estonian group. Thus, we argue that: (i) cultural and social backgrounds influence technology acceptance; (ii) technology acceptance was rather mediated by the absence of positive feelings rather than cybersickness.

Proposal for an ICF-based methodology to foster the return to work of persons with disability

BACKGROUND

Employment is an essential component of life as it provides income, sense of engagement and opportunities for personal development. Unemployment due to disability following an accident may have dramatic social and psychological consequences on individuals; it is thus fundamental to foster return to work of these persons.

OBJECTIVE

The present work was aimed to develop a methodology determining suitable jobs for people living with disability after a job-related accident.

METHODS

The Occupational Information Network (O*NET) taxonomy was combined with the International Classification of Functioning, Disability and Health (ICF) to match individual resources with specific job requirements. ICF Linking Rules were employed by two independent groups of researchers to associate ICF codes to O*NET skill and ability descriptors.

RESULTS

O*NET descriptors were linked to 92 unique ICF codes. A "Criticality score" combining ICF and O*NET features to assess suitability of selected jobs for persons with disabilities was also proposed.

CONCLUSIONS

The proposed methodology represents a novel instrument to support return to work; the capability to assess specific work-related facets through the lens of both the ICF model and O*NET taxonomy would conceivably provide vocational rehabilitation specialists and occupational therapists with a useful tool fostering job placement of workers with disability.

An immersive virtual reality-based application for treating ADHD: A remote evaluation of acceptance and usability

Introduction

Virtual reality (VR) is a digital technology currently considered to implement rehabilitation programs for children with ADHD, a disorder characterised by inattention, overactivity and impulsiveness. This study presents the results of the acceptance and usability of a VR application developed for children with ADHD aiming to provide an environment capable of supporting the development of the different attentional components. Due to COVID-19 restrictions, this study had the secondary aim of assessing whether a remote evaluation was feasible and meaningful.

Methods

A sample of 20 clinical experts (neuro and psychomotor therapists of the developmental age) was involved in assessing the proposed environment. Two different tools have been applied: the Technology Acceptance Model (TAM-3) questionnaire and a semi-structured interview were self-administered. Six sessions were planned in total, and each one lasted 30 min.

Results

With respect to the acceptance of the system, the mean of the answers given is for most of the constructs greater than 4, showing agreement among experts. Cronbach alpha and correlations of subscales seem to confirm the reliability of measures. According to results from the interviews, the developed application has shown versatility in being able to be applied to the heterogeneity of the disorder and it was also possible to obtain valuable insights on possible additional features and functionalities. Regarding the secondary aim, the collected outcomes were positive: all the participants were satisfied with what they could perceive about the application.

Conclusions

The results of this work pave the way for a future validation study with children due to the active participation of clinicians and their unanimous positive judgement confirming that the application was considered user-friendly and well accepted.

Acceptance and Usability of Immersive Virtual Reality in Older Adults with Objective and Subjective Cognitive Decline

Background: Virtual reality (VR) has recently emerged as a promising means for the administration of cognitive training of seniors at risk of dementia. Immersive VR could result in increased engagement and performances; however, its acceptance in older adults with cognitive deficits still has to be assessed. Objective: To assess acceptance and usability of an immersive VR environment requiring real walking and active participants’ interaction. Methods: 58 seniors with mild cognitive impairment (MCI, n = 24) or subjective cognitive decline (SCD, n = 31) performed a shopping task in a virtual supermarket displayed through a head-mounted display. Subjective and objective outcomes were evaluated. Results: Immersive VR was well-accepted by all but one participant (TAM3 positive subscales > 5.33), irrespective of the extent of cognitive decline. Participants enjoyed the experience (spatial presence 3.51±0.50, engagement 3.85±0.68, naturalness 3.85±0.82) and reported negligible side-effects (SSQ: 3.74; q1-q3:0–16.83). The environment was considered extremely realistic, such as to induce potentially harmful behaviors: one participant fell while trying to lean on a virtual shelf. Older participants needed more time to conclude trials. Participants with MCI committed more errors in grocery items’ selection and experienced less “perceived control” over the environment. Conclusion: Immersive VR was acceptable and enjoyable for older adults in both groups. Cognitive deficits could induce risky behaviors, and cause issues in the interactions with virtual items. Further studies are needed to confirm acceptance of immersive VR in individuals at risk of dementia, and to extend the results to people with more severe symptoms.

An Immersive Motor Protocol for Frailty Rehabilitation

Frailty is a pre-clinical condition that worsens physical health and quality of life. One of the most frequent symptoms of frailty is an increased risk of falling. In order to reduce this risk, we propose an innovative virtual reality motor rehabilitation program based on an immersive tool. All exercises will take place in the CAVE, a four-screen room with a stationary bike. The protocol will include two types of exercises for the improvement of balance: "Positive Bike" and "Avoid the Rocks." We will choose evaluation scales related to the functional aspects and subjective perception of balance. Our aim is to prove that our innovative motor rehabilitation protocol is as effective as or more effective than classical rehabilitation.

Virtual reality-based wheelchair simulators: A scoping review

Sense of presence (SoP) has recently emerged as one of the key elements promoting the effectiveness of virtual reality-based training programs. In the context of wheelchair simulators (WSs), the effectiveness of the simulation has been sought using different perception and interaction devices, providing the end-users with different levels of SoP. We performed a scoping review searching scientific and grey literature databases with the aim of assessing the extent of published research dealing with SoP and effectiveness of WSs. Sixty-two articles, describing 29 WSs, were included in the review. In spite of promising results, the high heterogeneity of the employed technological solutions, of the training programs and of their outcomes precluded drawing definitive conclusions about the optimal solution for the enhancement of SoP and thus of WSs' effectiveness. Future research should focus on controlled trials in order to help researchers in assessing the most suitable technologies and methodologies for the application of WSs in clinical practice.

Analysis for the design of a novel integrated framework for the return to work of wheelchair users

BACKGROUND

Return to work represents an important milestone for workers who were injured during a workplace accident, especially if the injury results in needing a wheelchair for locomotion.

OBJECTIVE

The aim of the study was to design a framework for training novice wheelchair users in regaining autonomy in activities of daily living and in the workplace and for providing medical personnel with objective data on users' health and work-related capabilities.

METHODS

The framework design was accomplished following the "Usability Engineering Life Cycle" model. According to it, three subsequent steps defined as "Know your User", "Competitive Analysis" and "Participatory Design" have been carried out to devise the described framework.

RESULTS

The needs of the end-users of the framework were identified during the first phase; the Competitive Analysis phase addressed standard care solutions, Virtual Reality-based wheelchair simulators, the current methodologies for the assessment of the health condition of people with disability and the use of semantic technologies in human resources. The Participatory Design phase led to the definition of an integrated user-centred framework supporting the return to work of wheelchair users.

CONCLUSION

The results of this work consists in the design of an innovative training process based on virtual reality scenarios and supported by semantic web technologies. In the near future, the design process will proceed in collaboration with the Italian National Institute for Insurance against Accidents at Work (INAIL). The whole framework will be then implemented to support the current vocational rehabilitation process within INAIL premises.

Effects of Combined Physical and Cognitive Virtual Reality-Based Training on Cognitive Impairment and Oxidative Stress in MCI Patients: A Pilot Study

The growing elderly population and the increased incidence of mild cognitive impairment (MCI) and Alzheimer's disease (AD) call for the improvement of the quality and the efficacy of the healthcare and social support services. Exercise and cognitive stimulation have been demonstrated to mitigate cognitive impairment and oxidative stress (OxS) has been recognized as a factor that contributes to the advancement of neurodegenerative diseases. Taking these aspects into account, the impact of a novel virtual reality (VR)-based program combining aerobic exercise and cognitive training has been evaluated in the pilot study proposed here. Ten patients (aged 73.3 ± 5.7 years) with MCI (Mini-Mental State Examination, MMSE: 23.0 ± 3.4) were randomly assigned to either 6 weeks physical and cognitive training (EXP) or control (CTR) group. Evaluations of cognitive profile, by a neuropsychological tests battery, and OxS, by collection of blood and urine samples, were performed before and at the end of the experimental period. The assessment of the patients' opinions toward the intervention was investigated through questionnaires. EXP group showed a tendency towards improvements in the MMSE, in visual-constructive test and visuo-spatial tests of attention, while CTR worsened. EXP group showed a greater improvement than CTR in the executive test, memory functions and verbal fluency. No statistical significance was obtained when comparing within and between both the groups, probably due to small number of subjects examined, which amplifies the effect of the slight heterogeneity in scores recorded. Despite a greater worsening of Daily Living Activities tests, all participants reported a better performance in real life, thanks to the elicited self-perceived improvement. After training intervention OxS (i.e., reactive oxygen species (ROS) production, oxidative damage of lipids and DNA) decreased resulting in significantly (range p < 0.05-0.001) lower in EXP vs. CTR group. Although not conclusive, the recorded effects in the present study are promising and suggest that this proposal would be a useful tool in support of cognitive training reducing OxS too. However, further studies on larger scale samples of patients are needed.

Characteristics, Usability, and Users Experience of a System Combining Cognitive and Physical Therapy in a Virtual Environment: Positive Bike

We present the architecture and usability evaluation of virtual reality system-"Positive Bike"-designed for improving cognitive and motor conditions in frail elderly patients. The system consists of a cycle-ergometer integrated in an immersive virtual reality system (CAVE) which allows combining motor and cognitive exercises according to a "dual-task" paradigm. We tested the usability and user's experience of the prototype in a pilot evaluation study that involved five elderly patients. The prototype was tested in one-session training to understand the limitations and areas for improvement of our system. The evaluation consisted in (i) usability assessment using the system usability scale; (ii) evaluation of user's engagement using the flow state scale; and (iii) expert evaluation involving interviews with domain experts. Results showed a good usability, both for system usability scale and the semi-structured interview. The level of flow (i.e., enjoyment with the task at hand) measured using the short flow state scale, was also high. Analysis of semi-structured interview carried out with domain experts provided further indications to improve the system. Overall, these findings show that, despite some limitations, the system is usable and provides an enjoyable user's experience.

Difficult mask ventilation in obese patients: analysis of predictive factors

BACKGROUND

This study aimed to determine the accuracy of commonly used preoperative difficult airway indices as predictors of difficult mask ventilation (DMV) in obese patients (BMI >30 kg/m2).

METHODS

In 309 consecutive obese patients undergoing general surgery, the modified Mallampati test, patient's Height/Thyromental distance ratio, Inter-Incisor Distance, Protruding Mandible (PM), history of Obstructive Sleep Apnea and Neck Circumference (NC) were recorded preoperatively. DMV was defined as Grade 3 mask ventilation (MV) by the Han's scale (MV inadequate, unstable or requiring two practitioners). Data are shown as means±SD or number and proportions. Independent DMV predictors were identified by multivariate analysis. The discriminating capacity of the model (ROC curve area) and adjusted weights for the risk factors (odds ratios) were also determined.

RESULTS

BMI averaged 42.5±8.3 kg/m2. DMV was reported in 27 out of 309 patients (8.8%; 95%CI 5.6-11.9%). The multivariate analysis retained NC (OR 1.17; P<0.0001), limited PM (1.99; P=0.046) and Mallampati test (OR 2.12; P=0.009) as risk predictors for DMV. Male gender was also included in the final model (OR 1.87; P=0.06) as biologically important variable albeit the borderline statistical significance. The model yielded a good discriminating capacity (ROC curve 0.85). The four parameters were used to create an unweighted prediction score (ROC curve 0.84) with >2 associated factors as the best discriminating point for DMV.

CONCLUSION

Obese patients show increased incidence of DMV with respect to the undifferentiated surgical population. Limited PM, Mallampati test and NC are important DMV predictors.

Regional anesthesia for carotid endarterectomy: a comparison between ropivacaine and levobupivacaine

BACKGROUND

This study compares ropivacaine and levobupivacaine when administered for cervical plexus block. The authors therefore compared the arterial pressure profile and the incidence of hypotension between drugs.

METHODS

Forty-eight patients scheduled for carotid artery surgery (American Society of Anesthesiologists [ASA] 2-3) were randomly assigned to receive levobupivacaine or ropivacaine (24 patients each). Neurological status, arterial pressure profile and control of postoperative pain were the main observed parameters. All patients had severe carotid stenosis (>80%) and/or had suffered transient ischemic attacks (TIAs) or preoperative strokes. The same team performed anesthesia and surgery for carotid endarterectomy; the cervical block was performed according to Moore's technique.Arterial pressure, heart rate and S(a)O(2p) were monitored continuously with particular regard to T0 (baseline), T1 (immediately before carotid clamping), T2 (immediately before declamping) and T3 (at the end of the procedure). Hypotension was defined as the fall of arterial systolic pressure 30% below baseline or less than 100 mmHg.

RESULTS

Arterial pressure fell significantly in both groups at T1 with respect to T0 (P<0.0001). Levobupivacaine patients showed higher mean arterial pressure on T0 (112+/-12 mmHg versus 103+/-7 mmHg; P<0.05), thus suggesting a more pronounced vasodilator effect, as confirmed by the larger drop of arterial diastolic pressure (P=0.007). An absolute 6% difference of hypotension-related drug was recorded with levobupivacaine (19%) as compared with ropivacaine (13%) (P=0.28).

CONCLUSIONS

Levobupivacaine has a greater vasodilatory effect than ropivacaine. Its higher incidence of hypotension, although not statistically significant, suggests ropivacaine as the drug of choice for cervical plexus block.

Decreased fluid volume to reduce organ damage: a new approach to burn shock resuscitation? A preliminary study

OBJECTIVE

To evaluate the impact of decreased fluid resuscitation on multiple-organ dysfunction after severe burns. This approach was referred to as "permissive hypovolaemia".

METHODS

Two cohorts of patients with burns>20% BSA without associated injuries and admitted to ICU within 6 h from the thermal injury were compared. Patients were matched for both age and burn severity. The multiple-organ dysfunction score (MODS) by Marshall was calculated for 10 days after ICU admission. Permissive hypovolaemia was administered by a haemodynamic-oriented approach throughout the first 24-h period. Haemodynamic variables, arterial blood lactates and net fluid balance were obtained throughout the first 48 h.

RESULTS

Twenty-four patients were enrolled: twelve of them received the Parkland Formula while twelve were resuscitated according to the permissive hypovolaemic approach. Permissive hypovolaemia allowed for less volume infusion (3.2+/-0.7 ml/kg/% burn versus 4.6+/-0.3 ml/kg/% burn; P<0.001), a reduced positive fluid balance (+7.5+/-5.4 l/day versus +12+/-4.7 l/day; P<0.05) and significantly lesser MODS Score values (P=0.003) than the Parkland Formula. Both haemodynamic variables and arterial blood lactate levels were comparable between the patient cohorts throughout the resuscitation period.

CONCLUSIONS

Permissive hypovolaemia seems safe and well tolerated by burn patients. Moreover, it seems effective in reducing multiple-organ dysfunction as induced by oedema fluid accumulation and inadequate O2 tissue utilization.

Myocardial necrosis in ICU patients with acute non-cardiac disease: a prospective study

OBJECTIVE

To ascertain if, after an episode of hypotension, unnoticed myocardial necrosis could occur in critical care patients with acute non-cardiac illness and to search for signs of cardiac necrosis.

DESIGN

A prospective observational study.

SETTING

General intensive care unit (ICU) at a tertiary level hospital.

PATIENTS

Thirty-one patients in two groups. Group 1 included 19 patients with severe sepsis/septic shock (ACCP/SCCM Consensus Conference). Group 2 included 12 patients with hypovolemic shock.

INTERVENTIONS

Biochemical markers of myocardial necrosis (cardiac troponin I (cTnI), creatine kinase (CK), creatine kinase MB mass (CKMB) and myoglobin) were measured at 12 h (T1), 24 h (T2) and 48 h (T3) after enrollment. A standard 12-lead ECG was recorded upon enrollment (T0) and at T2. Anomalous Q-waves or ST segment depression or elevation was considered diagnostic for acute myocardial infarction (AMI). A hypotensive episode (arterial systolic pressure < 90 mmHg at heart rate > 100 bpm) was considered moderate if it lasted 30-60 min or severe if longer than 60 min.

MEASUREMENTS AND RESULTS

At T0 none of the patients had AMI on ECG. At T2 a non-Q AMI developed in five patients. Increased levels of troponin I, myoglobin, CK and CKMB were found in 74.2 %, 96.8 %, 74.2 % and 67.7 % of the patients, respectively. Cardiac troponin I increased in 11 out of 19 septic patients and in all hypovolemic patients. There was a significant difference between the groups (p < 0.05). All biochemical markers increased in relationship to the degree of hypotension with cTnI again showing a significant difference. The longer the hypotensive episode was, the greater was the increase (moderate hypotension: median 1.16; quartiles 0.55-3.44 ng/ml, severe hypotension: median 8.53; quartiles 1.1-20.7 ng/ml; p < 0.05). Abnormal levels of cTnI were more frequent in non-survivors than in survivors (p < 0.05).

CONCLUSIONS

Hypotension may cause cardiac damage in critically ill patients with acute non-cardiac diseases as shown by abnormal levels of cTnI. It is likely that a high number of these myocardial necroses may go unnoticed on the ECG.

[Group A beta-hemolytic streptococcus infection and varicella]

The case of a 3-year-old boy affected with varicella associated to acute cellulitis by group A beta-hemolytic streptococci is reported. The causes of hospitalization were: high fever, decline of condition, onset of scarlet exanthema and a severe swelling in the inguinoscrotal area, during varicella. The diagnosis of streptococcal infection was confirmed by positive pharyngeal tampon, scarlet exanthema and following rise of ASLO. Since the association of these two infections is reported in literature more and more frequently, the possible causes and precautionary measures are analysed.

Antithrombin III (ATIII) replacement therapy in patients with sepsis and/or postsurgical complications: a controlled double-blind, randomized, multicenter study

BACKGROUND

ATIII is decreased in sepsis and/or shock and its baseline value correlates with mortality. The efficacy of ATIII therapy on mortality was assessed in a selected group of patients admitted to the intensive care unit (ICU) in a double-blind, randomized, multicenter study.

METHODS

120 patients admitted to the ICU with an ATIII concentration < 70% were randomized to receive ATIII (total dose 24000 units) or placebo treatment for 5 days; 56 patients had septic shock.

RESULTS

ATIII concentrations in the treated group remained constant throughout the treatment period (range 97-102%). The Kaplan-Meier analysis showed no difference in overall survival between the two groups: 50 and 46% for ATIII and placebo, respectively. Septic shock and hemodynamic support were unbalanced in the two groups at admission. Therefore the Cox analysis was carried out after adjusting for these two variables. Treatment with ATIII decreases the risk of death with an odds ratio (OR) of 0.56. Of the covariates analyzed, septic shock and the baseline multiple organ failure score were negatively associated with survival and plasma activity level was positively associated with survival with an OR of 0.97 for each 1% increase in the ATIII plasma concentration at baseline.

CONCLUSIONS

The results of ATIII treatment in this population of patients suggests that replacement therapy reduces mortality in the subgroup of septic shock patients only.

Sudden death in a child due to rare endocranial neoformation

A case of unexpected death in a six-year-old child, who died after a period of non-specific symptoms and clinical signs, is described. The cause of death was a pilocytic astrocytoma of the pontocerebellar angle, rare with regard to location and histology. The authors have reviewed the literature, which was scanty.

[Report of a case of celiac disease associated with transient erythroblastopenia in pediatric age]

Authors reports a rare case of association between two pathologies that, even if apparently very different, are both immunologically determined: celiac disease (CD) and transient erythroblastopenia of childhood (TEC). Such an association may be less rare commonly thought and this may be true for other autoimmune diseases, too. Clinical and pathological observations, together with etio-pathogenetic hypotheses, are discussed.

The influence of length of stay in the ICU on power of discrimination of a multipurpose severity score (SAPS). ARCHIDIA

OBJECTIVE

To assess how the power of discrimination of a multipurpose severity score (Simplified Acute Physiology Score; SAPS) changes in relation to the length of stay (LOS) in the intensive care unit (ICU).

DESIGN

In order to compute the SAPS probability, a model derived from logistic regression was developed in a cohort of 8059 patients. Measures of calibration (goodness-of-fit statistics) and discrimination [receiver operating characteristic (ROC) curve and relative area under the curve (AUC)] were adopted in a developmental set (5389 patients) and a validation set (2670 patients), both randomly selected. Once the logit was developed and the model validated, the whole database (8059 patients) was again assembled. To evaluate the accuracy of first-day SAPS probability over time, area under the ROC curve was computed for each of the initial 10 days of ICU care and for day 15.

SETTING

24 Italian ICUs.

PATIENTS

A total of 8059 patients out of 10065 consecutive admissions over a period of 3 years (1990-1992) were included in this study. Patients whose SAPS was not correctly compiled (n = 687), patients younger than 18 years (n = 442), and patients whose LOS was less than 24 h (n = 877) were excluded from this analysis.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The logistic model gave good results in terms of calibration and discrimination, both in the developmental set (goodness-of-fit: chi 2 = 9.24, p = 0.32; AUC = 0.79 +/- 0.01) and in the validation set (goodness-of-fit: chi 2 = 8.95, p = 0.537; AUC = 0.78 +/- 0.01). The AUC for the whole database showed a loss in discrimination closely related to LOS: 0.79 +/- 0.01 at a day 1 and 0.59 +/- 0.02 at day 15.

CONCLUSION

The logistic model that we developed meets high standards for discrimination and calibration. However, SAPS loses its discriminative power over time; accuracy of prediction is maintained at an acceptable level only in patients who stay in the ICU no longer than 5 days. The stay in the ICU represents a complex variable, which is not predictable, that influences the performance of SAPS on the first day.

[Description of two cases of transient hyperphosphatasemia in infancy and childhood]

The authors describe two cases of benign transient hyperphosphatesamia of infancy. This form is not so frequent in childhood and the following criteria must be present for a correct diagnosis: 1) Patient age of less than 5 years. 2) Variable symptoms. 3) No bone or liver disease noted on physical examination. 4) No other biochemical or laboratory evidence for bone or liver disease. 5) A return to normal serum alkaline phosphatase levels within 4 months with no sequelae. We want underline the uselessness of vitamin D therapy and the importance of a deepened study about biochemical and laboratory parameters in all patients affected by alkaline hyperphosphatesamia, to exclude a possible severe disease.

[Anemia and hepatosplenomegaly: search for the protozoon?]

An eight-months-old infant presenting with anemia, hepatosplenomegaly, hypoalbuminemia and polyclonal hypergammaglobulinemia was finally found to be affected by visceral leishmaniasis, after having suspected oncohaematologic problems. Diagnosis was confirmed by bone marrow aspiration. Complete recovery was achieved with antimonial N-methylglucamine (Glucantim) administered IM.

Technical aspects of oxygen saving devices

Oxygen economizing devices have been extensively studied, both at rest and during muscular exercise, in an attempt to increase the autonomy of a portable oxygen apparatus. The aim of this study is threefold: first, to suggest a simple method to verify in a simple way the technical accuracy of a demand flow oxygen delivery device; second, to suggest how we can monitor in a simple way the clinical efficacy of an economizer; and third, to remember that we can utilize an oxygen saving device to give a better protection than nasal prongs against the worsening of HbO2 desaturation induced by exercise.

A reservoir nasal cannula improves protection given by oxygen during muscular exercise in COPD

We verified the utility of an oxygen economizer (Pendant Oxymizer) in assuring greater protection than nasal prongs against worsening of oxyhemoglobin resting desaturation (delta SaO2) induced by muscular exercise in 16 patients (ten with chronic obstructive pulmonary disease [COPD] and six with restrictive pulmonary disease). This worsening was quantified as desaturation surface accumulated within five minutes of exercise and was expressed in arbitrary units (au). Each patient carried out the same exercise three times, in a randomized fashion (breathing air or breathing supplemental oxygen [3 L/min] delivered by either nasal prongs or by oxygen economizer). In patients with obstructive disease, delta SaO2 was reduced from 38 +/- 12.0 au when they were breathing air to 18.1 +/- 11.7 au when breathing oxygen by nasal prongs (p less than 0.001) and to 10.1 +/- 9.5 au when breathing oxygen by economizer (p less than 0.001). In patients with restrictive disease, delta SaO2 was reduced from 35.6 +/- 9.9 au when breathing air to 14.9 +/- 10.2 au breathing oxygen by nasal prongs (p less than 0.01) and to 13.7 +/- 10.3 au breathing oxygen by economizer (p less than 0.01). The difference between breathing by economizer and nasal prongs was significant (paired t-test; p less than 0.01) only in patients with COPD. One explanation could lie in the different values of the respiratory rate, which was significantly greater in patients with restrictive disease (20.7 +/- 1.2 breaths per minute at rest and 25.8 +/- 1.5 with exercise) than in patients with obstructive disease (15.3 +/- 1.2 breaths per minute at rest and 20.8 +/- 1.4 with exercise).

Effect of taurine supplementation on fat and bile acid absorption in patients with cystic fibrosis

Eleven children with cystic fibrosis (CF) and pancreatic insufficiency were given supplementation with taurine (30-40 mg/kg/day) for 2 months, while taking their usual dosage of enzymatic therapy. One patient dropped out of the study because she developed severe constipation. In the other 10 patients, urinary taurine excretion (88 +/- 30.1 mg/m2s.a./24 h) was similar to that of controls (86.2 +/- 6 mg/m2s.a./24 h) before taurine and increased markedly after supplementation (618.2 +/- 79.97 mg/m2s.a./24 h), indicating efficient intestinal absorption. Their coefficient of fat absorption was 81.2 +/- 2.3% and increased significantly after taurine (91.3 +/- 1.13%; p less than 0.01); the area under the curve of plasma triglyceride postprandial levels (1 +/- 0.1 mg X min/ml) also increased significantly after taurine (1.4 +/- 0.3 mg X min/ml; p less than 0.05), showing values very similar to those of controls. Conversely, no change was observed in the serum postprandial levels of glycocholic acid: the maximum postprandial peak before (1.2 +/- 0.3 mumol/l) and after taurine (1 +/- 0.1 mumol/l) remained significantly lower than in controls (2.4 +/- 0.3 mumol/l); p less than 0.01 and p less than 0.001, respectively. Mean total fecal bile acid (BA) excretion was 10.24 +/- 2.15 mg/kg/day before taurine and 12.8 +/- 4.27 mg/kg/day after taurine (normal pediatric values, 2.91 +/- 1.1 mg/kg/day); however, in the individual patients we found a variable trend, four of them showing a net increase in fecal BA excretion.(ABSTRACT TRUNCATED AT 250 WORDS)

A portable oxygen system corrects hypoxemia without significantly increasing metabolic demands

Some patients with chronic cor pulmonale have hypoxemia only during normal daily activity. This can be corrected by portable oxygen. Whether or not the weight of the apparatus (4.2 kg) adds an additional metabolic demand of sufficient magnitude to cancel or outweigh the advantages of portable oxygen is the subject of this report in 6 patients with chronic obstructive pulmonary disease and 2 with kyphoscoliosis. All received standardized treadmill exercise while breathing room air, and the same exercise with a portable liquid oxygen system sitting on the floor or carried by the patients. The additional load created only a 6.7% increase in CO2 production and did not reverse the supplemental oxygen benefit to arterial oxygen saturation under the experimental conditions of the study.

Value of nocturnal monitoring of transcutaneous O2 and CO2 pressures in adults with respiratory failure

We have evaluated the reliability of the transcutaneous (t.c.) method of measurement of arterial PO2 and PCO2 in adult man. In 33 simultaneous measurements of 9 normals and 12 patients with a wide range of hypoxemia, we found: t.c. PCO2 = 3.62 + 1.29 PaCO2 +/- 7.3 (r = 0.96) and t.c. PO2 = 11.14 + 0.86 PaO2 +/- 9.89 (r = 0.92). Recalculating t.c. PCO2 to 37 degrees C we can obtain: t.c. PCO2 = 2.7 + 0.97 X PaCO2, stating that there is no significant difference between t.c. PCO2 and PaCO2. The t.c. apparatus detects 10 and 90% O2 pressure changes with a delay of time of about 15 s and 1 min, respectively; the t.c. method is therefore not suitable for detecting changes in PaO2 caused by sleep apnea of short duration. On the contrary the t.c. method provided a useful monitoring of arterial PO2 and PCO2 changes during the night in chronic obstructive pulmonary disease (COPD) and non-COPD patients. A nocturnal monitoring of t.c. PO2 and PCO2 seems: (a) absolutely necessary in non-COPD hypoxemics, especially if total lung capacity (TLC) and/or residual volume (RV) are significantly reduced; (b) not absolutely necessary in COPD hypoxemics, provided they have an enlarged TLC and/or a very expanded RV; (c) advisable in intermediate situations, e.g., in COPD hypoxemics with an associated restrictive disorder caused by heart failure, congestion of pulmonary bed, parenchymal or rib cage disease, in order to establish the optimal concentration of oxygen for each patient and to avoid severe nocturnal hypoxemia without producing a dangerous rise in PaCO2.