Moderate associations between BDNF Val66Met gene polymorphism, musical expertise, and mismatch negativity

Auditory predictive processing relies on a complex interaction between environmental, neurophysiological, and genetic factors. In this view, the mismatch negativity (MMN) and intensive training on a musical instrument for several years have been used for studying environment-driven neural adaptations in audition. In addition, brain-derived neurotrophic factor (BDNF) has been shown crucial for both the neurogenesis and the later adaptation of the auditory system. The functional single-nucleotide polymorphism (SNP) Val66Met (rs6265) in the BDNF gene can affect BDNF protein levels, which are involved in neurobiological and neurophysiological processes such as neurogenesis and neuronal plasticity. In this study, we hypothesised that genetic variation within the BDNF gene would be associated with different levels of neuroplasticity of the auditory cortex in 74 musically trained participants. To achieve this goal, musicians and non-musicians were recruited and divided in Val/Val and Met- (Val/Met and Met/Met) carriers and their brain activity was measured with magnetoencephalography (MEG) while they listened to a regular auditory sequence eliciting different types of prediction errors. MMN responses indexing those prediction errors were overall enhanced in Val/Val carriers who underwent intensive musical training, compared to Met-carriers and non-musicians with either genotype. Although this study calls for replications with larger samples, our results provide a first glimpse of the possible role of gene-regulated neurotrophic factors in the neural adaptations of automatic predictive processing in the auditory domain after long-term training.

Language Intervention Instead of Speech Intervention for Children With Cochlear Implants

Cochlear implants are a standard rehabilitation option for children with severe hearing loss or deafness, allowing access to speech sounds necessary for the development of spoken language. However, the speech-language outcomes of pediatric cochlear implant users vary widely and are not directly or exclusively linked to technology but to combinations of individual audiological, personal, technical, and habilitational factors. These combinations may not favor spoken language development, which may further be linked to the issue of prior insistence on spoken language learning and associated with a high risk of language deprivation. Here, we discuss the outcomes of cochlear implantation from a habilitative perspective and lay down the efforts and resources necessary for the development of communication competence after cochlear implantation rather than the achievement of specific hearing, language, or speech skills that have limited socioemotional and educational contributions and do not guarantee an independent or productive life.

A magnetoencephalography study of first-time mothers listening to infant cries

Studies using magnetoencephalography (MEG) have identified the orbitofrontal cortex (OFC) to be an important early hub for a “parental instinct” in the brain. This complements the finding from functional magnetic resonance imaging studies linking reward, emotion regulation, empathy, and mentalization networks to the “parental brain.” Here, we used MEG in 43 first-time mothers listening to infant and adult cry vocalizations to investigate the link with mother–infant postpartum bonding scores and their level of sleep deprivation (assessed using both actigraphy and sleep logs). When comparing brain responses to infant versus adult cry vocalizations, we found significant differences at around 800–1,000 ms after stimuli onset in the primary auditory cortex, superior temporal gyrus, hippocampal areas, insula, precuneus supramarginal gyrus, postcentral gyrus, and posterior cingulate gyrus. Importantly, mothers with weaker bonding scores showed decreased brain responses to infant cries in the auditory cortex, middle and superior temporal gyrus, OFC, hippocampal areas, supramarginal gyrus, and inferior frontal gyrus at around 100–300 ms after the stimulus onset. In contrast, we did not find correlations with sleep deprivation scores. The significant decreases in brain processing of an infant’s distress signals could potentially be a novel signature of weaker infant bonding in new mothers and should be investigated in vulnerable populations.

Brain recognition of previously learned versus novel temporal sequences: a differential simultaneous processing

Memory for sequences is a central topic in neuroscience, and decades of studies have investigated the neural mechanisms underlying the coding of a wide array of sequences extended over time. Yet, little is known on the brain mechanisms underlying the recognition of previously memorized versus novel temporal sequences. Moreover, the differential brain processing of single items in an auditory temporal sequence compared to the whole superordinate sequence is not fully understood. In this magnetoencephalography (MEG) study, the items of the temporal sequence were independently linked to local and rapid (2–8 Hz) brain processing, while the whole sequence was associated with concurrent global and slower (0.1–1 Hz) processing involving a widespread network of sequentially active brain regions. Notably, the recognition of previously memorized temporal sequences was associated to stronger activity in the slow brain processing, while the novel sequences required a greater involvement of the faster brain processing. Overall, the results expand on well-known information flow from lower- to higher order brain regions. In fact, they reveal the differential involvement of slow and faster whole brain processing to recognize previously learned versus novel temporal information.

Rapid encoding of musical tones discovered in whole-brain connectivity

Information encoding has received a wide neuroscientific attention, but the underlying rapid spatiotemporal brain dynamics remain largely unknown. Here, we investigated the rapid brain mechanisms for encoding of sounds forming a complex temporal sequence. Specifically, we used magnetoencephalography (MEG) to record the brain activity of 68 participants while they listened to a highly structured musical prelude. Functional connectivity analyses performed using phase synchronisation and graph theoretical measures showed a large network of brain areas recruited during encoding of sounds, comprising primary and secondary auditory cortices, frontal operculum, insula, hippocampus and basal ganglia. Moreover, our results highlighted the rapid transition of brain activity from primary auditory cortex to higher order association areas including insula and superior temporal pole within a whole-brain network, occurring during the first 220 ms of the encoding process. Further, we discovered that individual differences along cognitive abilities and musicianship modulated the degree centrality of the brain areas implicated in the encoding process. Indeed, participants with higher musical expertise presented a stronger centrality of superior temporal gyrus and insula, while individuals with high working memory abilities showed a stronger centrality of frontal operculum. In conclusion, our study revealed the rapid unfolding of brain network dynamics responsible for the encoding of sounds and their relationship with individual differences, showing a complex picture which extends beyond the well-known involvement of auditory areas. Indeed, our results expanded our understanding of the general mechanisms underlying auditory pattern encoding in the human brain.

The influence of drug therapy for obstructive sleep apnoea on couple life. Qualitative study grounded theory

Background

Obstructive sleep apnoea (OSA) is characterised by the collapse of the upper airway during sleep, which determine intermittent hypoxia and sleep fragmentation leading to snoring, impaired cognitive function, excessive daytime sleepiness, and cardiovascular impairments. These disorders have a significant impact on the quality of life and health of both patient and partner, determining stress and frustration also to the couple relationship, and to the workplace. Although the gold standard of treatment for OSA is the use of continuous positive airway pressure (CPAP), many patients find it uncomfortable both for them and for their partners (difficulty in partner intimacy, fear of disturbing their partner's sleep) with consequent low adherence to treatment in about 50% of OSA patients.

For these reasons, efforts to develop drug therapies for the treatment of OSA have been ongoing for at least 20 years. Recently, we conducted a randomized controlled trial (RCT) in Italy to test the combination of reboxetine (a noradrenergic agent) and oxybutynin (an antimuscarinic) for OSA treatment with promising results. The aim of this study is to understand how OSA drug therapy has influenced couples' life.

Methods

The study was conducted from February to March 2020 by the research nurse who participated during the trial. We interviewed 11 patients participating in the pharmacological RCT and 7 partners. The data analysis was conducted in order to collect the subjects' answers in categories, and to identify a core category as the central element for the explanation of the process.

Results

Interviews permitted to extrapolate 6 main categories and the relative subcategories for patients: 1) OSA: unconscious danger; 2) OSA and couple life (subcategories: sleepiness and nervousness, lack of sleep); 3) transitory situations; 4) drug therapy and couple (subcategories:change in intimacy and sleep quality); 5) motivation to help others (subcategories: therapy recommended for everyone; intention to continue); 6) partner awareness helps in adherence to therapy (subcategories: partner as caregiver, presence and proximity, partner support). While for partners, 7 main categories and the relative subcategories emerged: 1) apprehension and concern for the partner; 2) repercussions on daily life (subcategorie: discomfort); 3) OSA and the couple's lives; 4) drug therapy and couple; 5) support during therapy (subcategorie: before therapy, during therapy); 6) changes during drug therapy; 7) recommended therapy (subcategories: helping others, partner support). “The OSA is our problem” was the core category of the study that linked the categories together.

Conclusions

Drug therapy is well embraced by both patients and partners as it allows the couple to recover intimacy during sleep and in daily life. The results of this study provide useful information on the need to involve the partner in order to promote adherence to therapy.

Funding Acknowledgement

Type of funding sources: None.

Brain predictive coding processes are associated to COMT gene Val158Met polymorphism

Predicting events in the ever-changing environment is a fundamental survival function intrinsic to the physiology of sensory systems, whose efficiency varies among the population. Even though it is established that a major source of such variations is genetic heritage, there are no studies tracking down auditory predicting processes to genetic mutations. Thus, we examined the neurophysiological responses to deviant stimuli recorded with magnetoencephalography (MEG) in 108 healthy participants carrying different variants of Val158Met single-nucleotide polymorphism (SNP) within the catechol-O-methyltransferase (COMT) gene, responsible for the majority of catecholamines degradation in the prefrontal cortex. Our results showed significant amplitude enhancement of prediction error responses originating from the inferior frontal gyrus, superior and middle temporal cortices in heterozygous genotype carriers (Val/Met) vs homozygous (Val/Val and Met/Met) carriers. Integrating neurophysiology and genetics, this study shows how the neural mechanisms underlying optimal deviant detection vary according to the gene-determined cathecolamine levels in the brain.

Validation of self-reported hearing loss among adult Croatians: the performance of the Hearing Self-Assessment Questionnaire against audiometric evaluation

OBJECTIVE

The aim of this study was to validate the performance of a self-assessment hearing loss screening tool for adults against audiometric evaluation. Different audiological measurements were compared with the results of a 10-item Likert-type questionnaire named the Hearing Self-Assessment Questionnaire (HSAQ) to investigate its psychometric characteristics.

DESIGN

Participants underwent audiological evaluation and completed the HSAQ. The screening performance of the HSAQ was evaluated against three definitions of hearing loss: better-ear mean pure-tone thresholds >25 dBHL at 500-2000 Hz, 500-4000 Hz and 1000-4000 Hz.

STUDY SAMPLE

The study enrolled 112 participants aged between 24 and 88 years (mean age 56.24 years, ±12.92).

RESULTS

The HSAQ had high Cronbach's alpha and intraclass correlation coefficients and showed construct, concurrent and discriminant validity. Its screening characteristics proved very good or excellent, depending on the definition of hearing loss. Receiver operating characteristic curve analysis showed excellent accuracy of the HSAQ in the identification of better-ear high-frequency hearing loss and better-ear speech-frequency hearing loss, with respect to different cut-off points.

CONCLUSIONS

Given the ease with which it is administered and its good screening properties, the HSAQ can be useful in deciding whether adult clients should be referred to audiological evaluation due to reasonable suspicion of hypoacusis.

Preliminary analysis of reliability and validity of the questionnaire "Aural Rehabilitation Outcomes Profile" (PIRS)

Cilj ovog rada je provedba preliminarne analize pouzdanosti i valjanosti Profila ishoda rehabilitacije slušanja (PIRS) – upitnika samoprocjene namijenjenog kvantifikaciji funkcionalnih teškoća slušanja s obzirom na zvučno okruženje i obilježja sugovornika (1., 3. i 5. dio), učestalost pojave različitih kompenzacijskih komunikacijskih strategija i izraženost socio-emocionalnih posljedica SOS-a (4. dio), stupanj utjecaja SOS-a na svakodnevne aktivnosti (2. dio) te kvalitetu slušne izvedbe i zadovoljstvo dodijeljenim slušnim pomagalom (5. dio). Analiza navedenih metrijskih obilježja svakog pojedinog dijela PIRS-a provedena je na uzorku od 47 odraslih sudionika (37 korisnika slušnog pomagala i 10 čujućih osoba), a uključila je analizu Cronbachovih koeficijenata pouzdanosti i međuklasnih korelacijskih koeficijenata, provedbu faktorske analize, primjenu Mann-Whitney U Testa u ispitivanju razlika u samoprocjeni između čujućih i sudionika s oštećenjem sluha te korelacijsku analizu stupnjeva oštećenja sluha i rezultata samoprocjene. Rezultati navedenihpostupaka pokazali su da svi dijelovi PIRS-a posjeduju pouzdanost i valjanost čiji potencijal opravdava daljnje ispitivanje njihovih metrijskih svojstava s ciljem provjere kliničke primjene PIRS-a kao mjere ishoda rehabilitacije SOS-a.

A national study of iodine status in Albania

OBJECTIVE

The aim of the study was to determine the iodine status in Albania following 11 yr of iodine prophylaxis and to evaluate factors influencing the outcome.

DESIGN

Eight hundred and forty children, aged 6-13 yr, living in 4 different regions and 365 pregnant women living in the same areas, were enrolled for the study. The prevalence of goiter was assessed by palpation and ultrasound imaging and the urinary iodine and the iodine concentration in the salt of different commercial brands were evaluated. Presence of goiter in the family and their eating habits were also investigated as well as the use of iodized salt in the household.

MAIN OUTCOME

In children, the prevalence of goiter was 57.6% by palpation and 24.4% by ultrasound imaging. Median urinary iodine was 86.2 microg/l, with pronounced geographical variations (range 3.52-1079 microg/l). In particular, 29.1% of the children had urinary iodine <50 microg/l and 57.1% <100 microg/l. In pregnant women, the median urinary iodine was 85 microg/l. Median iodine concentration in household iodized salt was 21.2 mg/kg, with 60.3% of the brands being adequately and 39.7% non-adequately iodized. Almost all families (99.6%) claimed to use iodized salt.

CONCLUSION

Despite the introduction of iodine prophylaxis, there is still a mild iodine deficiency in Albania, particularly in the inner mountainous areas.

Regression of left ventricular hypertrophy and improvement of diastolic function in hypertensive patients treated with telmisartan

OBJECTIVES

The study was designed to test whether or not the angiotensin II receptor blocker telmisartan brings about regression of left ventricular (LV) concentric hypertrophy and whether or not these changes are associated with improved diastolic filling.

METHODS

An echocardiographic follow-up study was performed in 85 hypertensive patients (systolic blood pressure [SBP] >140 mmHg, diastolic blood pressure [DBP] >90 mmHg) and mild-to-moderate LV hypertrophy (LV mass index related to body surface area [LVMI] 117-150 g/m2 for men and 105-150 g/m2 for women) treated with telmisartan monotherapy 40-80 mg once daily for 1 year. Blood pressure, LVMI, left atrial (LA) volumes, and diastolic function were determined at baseline and after 3, 6, 9, and 12 months of treatment. Blood pressure was also monitored at all visits. Diastolic function was assessed by examination of transmitral inflow and pulmonary vein flow patterns.

RESULTS

Telmisartan reduced blood pressure; after 12 months, the mean+/-S.D. SBP and DBP were reduced from 144+/-10 to 126+/-8 mmHg (p<0.001) and from 98+/-8 to 86+/-7 mmHg (p<0.001), respectively. The LVMI was decreased from 119+/-7 to 109+/-3 g/m2 (p<0.001) after 12 months' telmisartan treatment. All patients had diastolic dysfunction at baseline. After 12 months' telmisartan treatment, a normal pattern of transmitral inflow was present in 21% of patients. The regression of LV hypertrophy observed after 12 months was associated with increased peak early diastolic velocity/peak late diastolic velocity ratio from 0.60+/-0.18 to 0.83+/-0.20 (p<0.001), shortened isovolumic relaxation time (IVRT) from 110+/-13 to 105+/-13 ms (p<0.001), and decreased deceleration time from 229+/-30 to 215+/-28 ms (p=0.002). Univariate analysis showed that shortened IVRT was related to a reduction in the LVMI and LA maximal and minimal volumes. In the multivariate analysis, the reduction in LVMI and the reduction in LA maximal and minimal volumes were independently associated with IVRT reduction.

CONCLUSIONS

Telmisartan 40-80 mg is effective in LV hypertrophy regression in hypertensive patients. The reduction in LVMI due to telmisartan monotherapy was associated with a significant improvement of diastolic filling parameters and with a significant reduction of LA volumes.

Bone metastases in the hip region: surgical treatment

Subjective factors of the patient such as age, weight, occupation, expectations, etc. must be carefully evaluated in terms of surgery. It is always important to remember life expectancy, and the choice of a surgical procedure must be based on it. Limited survival and possible radiation therapy must eliminate methods that require long healing times: we no longer use bone grafts because the risk of healing time taking up too much of the time left for the patient is too high. Reconstructions must have an immediate solidity allowing early use of the limb. Thus, in the proximal femur, we above all use protheses (traditional or modular RPS); in acetabular lesions that do not involve the joint surface, our treatment of choice is curettage with liquid nitrogen and cement, armed with screws and nails. Prostheses, which are always cemented, are assembled using bipolar cups; cases where lysis is so wide on the cotyloid side as to require THR are rare. The cotyles, in cases such as these, are those that allow for anchoring with several sites (Octopus type), the McMinn or, at times, common cotyles in PE.

Resection of the proximal humerus for metastases and replacement with RPS prosthesis

In the surgical treatment of metastatic lesions of the proximal humerus it is important to find solutions that eliminate pain and solve the mechanical problem in a short time and with reduced costs. In 90% of cases, intralesional curettage, freezing with liquid nitrogen and cement enhanced intramedullary instrumentation is capable of brilliantly solving the problems of these patients. When, instead, osteolysis involves the greater tuberosity and/or the joint region, resection of the proximal humerus followed by reconstruction with a modular prosthesis is indicated. Of those available on the market, the RPS system (LIMA) has features that make it equivalent to others, but at costs considerably lower. However, in reconstructions with prostheses, active abduction is significantly limited. A personal series of 20 patients is presented.

Monitoring of heavy metal deposition in Northern Italy by moss analysis

A survey of heavy metal deposition in the mountainous territories of Northern Italy was carried out in 1995-96. Moss samples (mainly Hylocomium splendens) were collected in a dense network of sites (about 3.2 sites/1000 km(2)) and the data of metal concentrations in moss tissues were statistically correlated with environmental and climatic factors, as well as with bulk deposition of elements and elemental concentrations in the soil. Three main geographic patterns of metal concentration in mosses could be defined: (1) Fe, Ni, and Cr, all derived both by soil particulates and anthropogenic emissions connected with ferrous metal manufacturing, were mostly concentrated in Northwestern Italy; (2) Cu and Zn, as typical multi-source elements, showed rather high concentrations with little ranges of variation over the whole area and small peaks reflecting local source points; (3) Cd and Pb reflected long-distance transport and showed highest concentrations in the regions with highest precipitation, especially in the Eastern Alps.

Heparin-induced thrombocytopenia in patients treated with unfractionated heparin: prevalence of thrombosis in a 1 year follow-up

BACKGROUND

Patients with unstable angina are usually treated with unfractionated heparin and aspirin, but very little is known about the prevalence of heparin-induced antibodies and their relation to thrombotic complications some time after the acute phase of unstable angina. The aim of the present study was to establish the prevalence of heparin-induced thrombocytopenia and the prevalence of heparin-dependent platelet-reactive antibodies in patients treated with unfractionated heparin and the occurrence of thrombosis in a 1 year follow-up.

METHODS

Patient population included 124 consecutive patients with unstable angina treated with unfractionated heparin for almost 5 days. The prevalence of heparin-dependent platelet-reactive antibodies using an ELISA assay was measured before the beginning of heparin therapy and after 7 and 40 days. The platelet count was measured at the same time and the presence of thrombotic occurrences was checked. Clinical follow-up lasted 1 year.

RESULTS

At baseline no one patient was positive for heparin-induced antibodies. On day 6, 38 patients (30%) produced a positive heparin-induced antibody result and 30 patients (24%) had an intermediate result. The majority of patients (74%) who developed antibodies became positive after 6 days of heparin therapy. The combined incidence of death, myocardial infarction, recurrent angina, urgent revascularization and stroke was 66% in patients with antibodies and 44% in patients without antibodies during a 1 year follow-up. The incidence of combined primary end points was statistically higher in patients positive for antibodies. The log-rank test was statistically significant (chi2 = 4.39, p < 0.01).

CONCLUSIONS

No one patient developed a clinical evidence of thrombocytopenia. Nevertheless thrombotic events during follow-up were more common in patients who developed heparin-induced antibodies. These patients need a more accurate evaluation and surveillance after hospital discharge.

Ketoacidosis and hyperosmolarity as first symptoms of type 1 diabetes mellitus following ingestion of high-carbohydrate-containing fluids

The concomitant occurrence of diabetic ketoacidosis and hyperosmolarity is reported in two children, as early symptoms of misdiagnosed type 1 diabetes mellitus. The precipitating factor for both severe metabolic abnormalities was the ingestion of a large amount of high-carbohydrate-containing fluids, a few days before admission. A similar situation has never been reported before in the literature. A successful therapeutic scheme is described.

[The nurse educator: an experience among immigrants from developing countries]

Immigration from developing countries to Italy is a recent fact; however, it is causing different problems, even to health. Among these, tuberculosis holds a position of prominence; it is usually endemic in its original countries, but it finds good condition to become acute again in the discomfort and poverty of home countries. The purpose of the work is to test and confirm the promoting and defensive function of health in nursing profession, thanks to a health education project for immigrants which aims at reducing tuberculosis presence. The instrument used is a lesson about tuberculosis characteristics which the proposal to make the tubercular test, right instrument for a precocious diagnosis. The positive results achieved, show us the right evidence that the nurse is an educator: immigrants have also been offered the possibility to defend their health.

[Unexpected accumulation of nitrogen in a circuit during low-flow anesthesia. Presentation of two clinical cases]

The authors report two cases of unexpected nitrogen accumulation in the circuit during low flow anaesthesia with a fresh gas flow of 600 ml/min (O2:N2O = 1.1). Though the presence in the anaesthesia circuit of nitrogen eliminated by the patient is a common feature of closed circuit and low flow techniques, the magnitude and the speed of increase of inert gas concentration (compared with data from previous experiences) were highly suspicious for an external source. This was readily identified as a "mini" leak (30 ml/min of N2) from the air flowmeter, although his valve was in fully closed position. The report depicts an uncommon cause of air entry in the anaesthesia circuit and confirms the need for monitoring gases and vapours when closed circuit and low flow techniques are employed.

[Variations of esophageal temperature during general anesthesia with a low-flow circuit]

BACKGROUND

Anaesthesia drugs cause the cutaneous vasodilatation that produces core temperature lowering at the beginning of general anaesthesia; when the thermal threshold for vasoconstriction is reached the cutaneous heat losses are decreased. Furthermore, the soda lime begins to produce water and heat after 40 minutes of closed circuit ventilation. WORK HYPOTHESIS: The technique of inhalatory anaesthesia affects the thermal loss of patients after some hours of ventilation.

DESIGN

Prospective randomized clinical trial.

SETTING

Surgical Clinical operating theatre of the University of Florence.

PATIENTS

50 patients submited to abdominal non vascular surgery, for longer than 2 hours, with xifo-pubic cut, subdivided into two groups with the same anthropometric characters and age; the first ventilated with open system, the second with low flow circuit (fresh gas flow 700 ml/min).

STATISTIC

"t" Student test;

MEASURES

Lower one third oesophageal and inspiratory jaw of the circuit temperatures recorded for three hours.

MAIN RESULTS

The savings of low flow anaesthesia begin to be significant in the third hour of anaesthesia.

CONCLUSIONS

The thermal saving of closed circuit anaesthesia is, very probably, related to the humidifying and the warming of inspired air by soda lime reaction; the effect is more evident if cutaneous losses are reduced.

Closed circuit anesthesia: preservation of the environment

Closed circuit anesthesia must be considered as a primary contributor enabling to reduce the damaging effect of anesthetic agents on the environment. Halogenated vapors and nitrous oxide damage both the macro-environment, i.e. the earth's atmosphere layer and the micro-environment, i.e. the operating room ambience. As nitrous oxide is one of the most toxic agents, and as pure oxygen is harmful to the lungs, a technique of closed circuit anesthesia has been developed which employs oxygen/air (0.35:0.35 l/min) as a carrier of isoflurane. The safety of this oxygen-air technique of closed circuit anesthesia has been demonstrated by the greater stability of oxygen concentrations in the circuit in comparison to the more extensively used oxygen-nitrous oxide technique.

[Respiratory mechanics and gas exchange in anesthesia for laparoscopic cholecystectomy]

OBJECTIVE

To evaluate the influence of endoabdominal CO2 insufflation during anaesthesia for laparoscopic cholecystectomy on airway pressure, gas exchange and their relationships.

DESIGN

Perspective; clinical investigation.

SETTING

Operating room at a central general hospital.

PATIENTS

14 patients (3 males and 11 females) ASA 1-2, non smokers, without lung disease, scheduled for elective laparoscopic cholecystectomy.

INTERVENTIONS

During balanced anaesthesia (N2O/O2, Fentanyl, Isoflurane), with fixed minute ventilation, endoperitoneal insufflation of CO2 held at constant pressure (21 cm H2O).

MEASUREMENTS

Serial measurements of: Airway pressure, near-static compliance, ETCO2, CO2 minute production, blood gas analysis and derived data: P(a-A)O2, P(a-ET)CO2, Vd/Vt.

MAIN RESULTS

During insufflation peak and pause pressures increased by 6 cm H2O and mean pressure; by 3 cm H2O; Compliance was reduced by 48%; PaO2 decreased evenly with time (p > 0.05) irrespective of the airway pressure. PaCO2, PECO2, VCO2 and Vd/Vt after a sharp increase stabilized at 30% (mean value) over the baseline. P(a-ET)CO2 and Vd/Vt fluctuate in the physiological range except for two short but significant changes (p > 0.05) at insufflation and desufflation time.

CONCLUSIONS

Laparoscopic technique for cholecystectomy, at least in healthy patients, produces relevant changes in airway pressures but only minor modifications of gas exchange, similar to those seen during general anaesthesia. This technique can be safely used for routine operation with standard monitoring equipment.

[Inhalation anesthesia in low-flow systems. Clinical evaluation of the kinetics of isoflurane in induction phase]

Closed circuit and low flow anaesthesia offer numerous advantages such as reduction of gas consumption, low cost, and less pollution in both the operating theatre and the environment. These procedures also offer increases in inspired gas humidity and temperature. However the time needed to attain the alveolar concentration MAC 95, is too long. Prefilling the whole circuit, the bellow and the bag with anaesthetic vapours shortens that time without overdosage.

[Closed circuit inhalation anesthesia. Consumption and cost]

Closed circuit anaesthesia (CCA) and minimal flow anaesthesia diminish inhalatory anaesthetic consumption. Consumption of inhalatory anaesthesia was calculated using two different techniques: CCA and "non rebreathing" system. Costs were compared on the basis of the official list price. The CCA allowed for reduced consumption at lower costs. The resulting annual savings are equal to one third of the total price of the whole apparatus with its complementary monitoring and control systems.