393 research outputs found
Laparoscopy Pneumoperitoneum Fuzzy Modeling
Abstract: Gas volume to intra-peritoneal pressure fuzzy modeling for evaluating pneumoperitoneum in videolaparoscopic surgery is proposed in this paper. The proposed approach innovates in using fuzzy logic and fuzzy set theory for evaluating the accuracy of the prognosis value in order to minimize or avoid iatrogenic injuries due to the blind needle puncture. In so doing, it demonstrates the feasibility of fuzzy analysis to contribute to medicine and health care. Fuzzy systems is employed here in synergy with artificial neural network based on backpropaga tion, multilayer perceptron architecture for building up numerical functions. Experimental data employed for analysis were collected in the accomplishment of the pneumoperitoneum in a random population of patients submitted to videolaparoscopic surgeries. Numerical results indicate that the proposed fuzzy mapping for describing the relation from the intra peritoneal pressure measures as function injected gas volumes succeeded in determinining a fuzzy model for this nonlinear system when compared to the statistical model
Relationship of arterial and exhaled CO2 during elevated artificial pneumoperitoneum pressure for introduction of the first trocar.
The present study evaluated the correlation between arterial CO2 and exhaled CO2 during brief high-pressure pneumoperitoneum. Patients were randomly distributed into two groups: P12 group (n=30) received a maximum intraperitoneal pressure of 12mmHg, and P20 group (n=37) received a maximum intraperitoneal pressure of 20mmHg. Arterial CO2 was evaluated by radial arterial catheter and exhaled CO2 was measured by capnometry at the following time points: before insufflation, once intraperitoneal pressure reached 12mmHg , 5 minutes after intraperitoneal pressure reached 12mmHg for the P12 group or 20mmHg for the P20 group, and 10 minutes after intraperitoneal pressure reached 12mmHg for the P12 group or when intraperitoneal pressure had decreased from 20mmHg to 12mmHg, for the P20 group. During brief durations of very high intraperitoneal pressure (20mmHg), there was a strong correlation between arterial CO2 and exhaled CO2. Capnometry can be effectively used to monitor patients during transient increases in artificial pneumoperitoneum pressure
Invasive monitoring of the clinical effects of high intra-abdominal pressure for insertion of the first trocar.
Background: To analyze the effects of transitory, high intra-abdominal pressure on clinical, hemodynamic, blood gas and metabolic parameters.

Methods: Sixty-seven laparoscopic patients were divided into groups P12 (n = 30, maximum intra-abdominal pressure of 12 mmHg) and P20 (n = 37, maximum intra-abdominal pressure of 20 mmHg). Through radial artery cannulation, mean arterial pressure (MAP) was assessed and blood gas analysis – pH, arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), bicarbonate (HCO3) and base excess (BE) – was performed. These parameters were evaluated in both groups at time point zero, before CO2 insufflation; at time point one (TP1), when intra-abdominal pressure of 12 mmHg was reached in both groups; at time point two (TP2), 5 minutes after reaching intra-abdominal pressure of 12 mmHg in group P12 and of 20 mmHg in group P20; and at time point three (TP3), 10 minutes after reaching intra-abdominal pressure of 12 mmHg in group P12 and 10 minutes after TP1 in group P20, when intra-abdominal pressure decreased from 20 mmHg to 12 mmHg. Values out of the normal range or the occurrence of atypical phenomena suggestive of organic disease indicated clinical changes.

Results: Significant variations in MAP, pH, HCO3 and BE were observed in group P20; these changes, however, were within normal limits. Clinical changes were also within normal limits, and no pathological phenomena were observed.

Conclusions: Brief, intra-abdominal hypertension for the insertion first trocar insertion causes variations in MAP, pH, HCO3 and BE without adverse effects, and it may protect from iatrogenic injury
Fuzzy logic as a decision-making support system for the indication of bariatric surgery based on an index (OBESINDEX) generated by the association between body fat and body mass index
Background: A Fuzzy Obesity Index (OBESINDEX) for use as an alternative in bariatric surgery indication (BSI) is presented. The search for a more accurate method to evaluate obesity and to indicate a better treatment is important in the world health context. BMI (body mass index) is considered the main criteria for obesity treatment and BSI. Nevertheless, the fat excess related to the percentage of Body Fat (%BF) is actually the principal harmful factor in obesity disease that is usually neglected. This paper presents a new fuzzy mechanism for evaluating obesity by associating BMI with %BF that yields a fuzzy obesity index for obesity evaluation and treatment and allows building up a Fuzzy Decision Support System (FDSS) for BSI.

Methods: Seventy-two patients were evaluated for both BMI and %BF. These data are modified and treated as fuzzy sets. Afterwards, the BMI and %BF classes are aggregated yielding a new index (OBESINDEX) for input linguistic variable are considered the BMI and %BF, and as output linguistic variable is employed the OBESINDEX, an obesity classification with entirely new classes of obesity in the fuzzy context as well is used for BSI.

Results: There is a gradual, smooth obesity classification and BSI when using the proposed fuzzy obesity index when compared with other traditional methods for dealing with obesity.

Conclusion: The BMI is not adequate for surgical indication in all the conditions and fuzzy logic becomes an alternative for decision making in bariatric surgery indication based on the OBESINDEX
Time without time: a stochastic clock model
We study a classical reparametrization-invariant system, in which ``time'' is
not a priori defined. It consists of a nonrelativistic particle moving in five
dimensions, two of which are compactified to form a torus. There, assuming a
suitable potential, the internal motion is ergodic or more strongly irregular.
We consider quasi-local observables which measure the system's ``change'' in a
coarse-grained way. Based on this, we construct a statistical timelike
parameter, particularly with the help of maximum entropy method and Fisher-Rao
information metric. The emergent reparametrization-invariant ``time'' does not
run smoothly but is simply related to the proper time on the average. For
sufficiently low energy, the external motion is then described by a unitary
quantum mechanical evolution in accordance with the Schr\"odinger equation.Comment: 18 pages; LaTeX. 4 (.ps) plus 2 (.gif) figure file
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