Evaluation of the effect of trendelenburg position duration on intracranial pressure in laparoscopic hysterectomies using ultrasonographic optic nerve sheath diameter measurements.

BACKGROUND: During laparoscopic surgery, pneumoperitoneum and Trendelenburg positioning applied to provide better surgical vision can cause many physiological changes as well as an increase in intracranial pressure. However, it has been reported that cerebral autoregulation prevents cerebral edema by regulating this pressure increase. This study aimed to investigate whether the duration of the Trendelenburg position had an effect on the increase in intracranial pressure using ultrasonographic optic nerve sheath diameter (ONSD) measurements. METHODS: The near infrared spectrometry monitoring of patients undergoing laparoscopic hysterectomy was performed while awake (T0); at the fifth minute after intubation (T1); at the 30th minute (T2), 60th minute (T3), 75th minute (T4), and 90th minute (T5) after placement in the Trendelenburg position; and at the fifth minute after placement in the neutral position (T6). RESULTS: The study included 25 patients. The measured ONSD values were as follows: T0 right/left, 4.18±0.32/4.18±0.33; T1, 4.75±0.26/4.75±0.25; T2, 5.08±0.19/5.08±0.19; T3, 5.26±0.15/5.26±0.15; T4, 5.36±0.11/5.37±0.12; T5, 5.45±0.09/5.48±0.11; and T6, 4.9±0.24/4.89±0.22 ( p < 0.05 compared with T0). ). No statistical difference was detected in all measurements in terms of MAP, HR and ETCO2 values compared to the T0 value (p > 0.05). CONCLUSIONS: It was determined that as the Trendelenburg position duration increased, the ONSD values ​​increased. This suggests that as the duration of Trendelenburg positioning and pneumoperitoneum increases, the sustainability of the mechanisms that balance the increase in intracranial pressure becomes insufficient. TRIAL REGISTRATION: This study was registered at Clinical Trials.gov on 21/09/2023 (registration number NCT06048900).

Characterization of internal jugular vein region-specific distension and flow patterns during progressive volume shifting.

Blood volume shifts during postural adjustment lead to irregular distension of the internal jugular vein (IJV). In microgravity, distension may contribute to flow stasis and thromboembolism, though the regional implications and associated risk remain unexplored. We characterized regional differences in IJV volume distension and flow complexity during progressive head-down tilt (HDT) (0°, -6°, -15°, -30°) using conventional ultrasound and vector flow imaging. We also evaluated low-pressure thigh cuffs (40 mmHg) as a fluid shifting countermeasure during -6° HDT. Total IJV volume expanded 139 ± 95% from supine position (4.6 ± 2.7 mL) to -30° HDT (10.3 ± 5.0 mL). Blood flow profiles had greater vector uniformity at the cranial IJV region (P < 0.01) and became more dispersed with increasing tilt (P < 0.01). Qualitatively, flow was more uniform throughout the IJV during its early flow cycle phase and more disorganized during late flow phase. This disorganized flow was accentuated closer to the vessel wall, near the caudal region, and during greater HDT. Low-pressure thigh cuffs during -6° HDT decreased IJV volume at the cranial region (-12 ± 15%; P < 0.01) but not the caudal region (P = 0.20), although flow uniformity was unchanged (both regions, P > 0.25). We describe a distensible IJV accommodating large volume shifts along its length. Prominent flow dispersion was primarily found at the caudal region, suggesting multidirectional blood flow. Thigh cuffs appear effective for decreasing IJV volume but effects on flow complexity are minor. Flow complexity along the vessel length is likely related to IJV distension during chronic volume shifting and may be a precipitating factor for flow stasis and future thromboembolism risk.NEW & NOTEWORTHY The internal jugular vein (IJV) facilitates cerebral outflow and is sensitive to volume shifts. Concerns about IJV expansion and fluid flow behavior in astronauts have surfaced following thromboembolism reports. Our study explored regional volume distension and blood flow complexity in the IJV during progressive volume shifting. We observed stepwise volume distension and increasing flow dispersion with head-down tilting across all regions. Flow dispersion may pose a risk of future thromboembolism during prolonged volume shifts.

Oscillations of Hemodynamic Parameters Induced by Negative Pressure Breathing in Healthy Humans.

INTRODUCTION: Negative pressure breathing is breathing with decreased pressure in the respiratory tract without lowering pressure acting on the torso. We lowered air pressure only during inspiration (NPBin). NPBin, used to increase venous return to the heart, is considered a countermeasure against redistribution of body fluids toward the head during spaceflight. We studied NPBin effects on circulation in healthy humans with an emphasis on NPBin-induced oscillations of hemodynamic parameters synchronous with breathing. We propose an approach to analyze the oscillations based on coherent averaging.METHODS: Eight men ages 24-42 yr participated in the NPBin and control series. During the series, to reproduce fluids shift observed under microgravity, subjects were supine and head down (-8°). Duration of NPBin was 20 min, rarefaction -20 cm H2O. Hemodynamic parameters were measured by Finometer. Electrical impedance measurements were used to estimate changes in blood filling of cerebral vessels.RESULTS: Mean values of hemodynamic parameters virtually did not change under NPBin, but NPBin induced oscillations of the parameters synchronous with respiration. Peak-to-peak amplitude under NPBin were: mean arterial pressure, 4 ± 1 (mmHg); stroke volume, 7 ± 3 (mL); and heart rate, 4 ± 1 (bpm). Electrical impedance of the head increased during inspiration. The increase under NPBin was three times greater than under normal breathing.DISCUSSION: Analysis of oscillations gives more information than analysis of mean values. NPBin induces short-term decrease in left ventricle stroke volume and arterial blood pressure during each inspiration; the decrease is compensated by increase after inspiration. NPBin facilitates redistribution of body fluids away from the head.Semenov YS, Melnikov IS, Luzhnov PV, Dyachenko AI. Oscillations of hemodynamic parameters induced by negative pressure breathing in healthy humans. Aerosp Med Hum Perform. 2024; 95(6):297-304.

The effect of inherent and incidental constraints on bimanual force control in simulated Martian gravity.

The ability to coordinate actions between the limbs is important for many operationally relevant tasks associated with space exploration. A future milestone in space exploration is sending humans to Mars. Therefore, an experiment was designed to examine the influence of inherent and incidental constraints on the stability characteristics associated with the bimanual control of force in simulated Martian gravity. A head-up tilt (HUT)/head-down tilt (HDT) paradigm was used to simulate gravity on Mars (22.3° HUT). Right limb dominant participants (N = 11) were required to rhythmically coordinate patterns of isometric forces in 1:1 in-phase and 1:2 multifrequency patterns by exerting force with their right and left limbs. Lissajous displays were provided to guide task performance. Participants performed 14 twenty-second practice trials at 90° HUT (Earth). Following a 30-min rest period, participants performed 2 test trials for each coordination pattern in both Earth and Mars conditions. Performance during the test trials were compared. Results indicated very effective temporal performance of the goal coordination tasks in both gravity conditions. However, results indicated differences associated with the production of force between Earth and Mars. In general, participants produced less force in simulated Martian gravity than in the Earth condition. In addition, force production was more harmonic in Martian gravity than Earth gravity for both limbs, indicating that less force distortions (adjustments, hesitations, and/or perturbations) occurred in the Mars condition than in the Earth condition. The force coherence analysis indicated significantly higher coherence in the 1:1 task than in the 1:2 task for all force frequency bands, with the highest level of coherence in the 1-4 Hz frequency band for both gravity conditions. High coherence in the 1-4 Hz frequency band is associated with a common neural drive that activates the two arms simultaneously and is consistent with the requirements of the two tasks. The results also support the notion that neural crosstalk stabilizes the performance of the 1:1 in-phase task. In addition, significantly higher coherence in the 8-12 Hz frequency bands were observed for the Earth condition than the Mars condition. Force coherence in the 8-12 Hz bands is associated with the processing of sensorimotor information, suggesting that participants were better at integrating visual, proprioceptive, and/or tactile feedback in Earth than for the Mars condition. Overall, the results indicate less neural interference in Martian gravity; however, participants appear to be more effective at using the Lissajous displays to guide performance under Earth's gravity.

Myths and Methodologies: Understanding the health impact of head down bedrest for the benefit of older adults and astronauts. Study protocol of the Canadian Bedrest Study.

Weightlessness during spaceflight can harm various bodily systems, including bone density, muscle mass, strength and cognitive functions. Exercise appears to somewhat counteract these effects. A terrestrial model for this is head-down bedrest (HDBR), simulating gravity loss. This mirrors challenges faced by older adults in extended bedrest and space environments. The first Canadian study, backed by the Canadian Space Agency, Canadian Institutes of Health Research, and Canadian Frailty Network, aims to explore these issues. The study seeks to: (1) scrutinize the impact of 14-day HDBR on physiological, psychological and neurocognitive systems, and (2) assess the benefits of exercise during HDBR. Eight teams developed distinct protocols, harmonized in three videoconferences, at the McGill University Health Center. Over 26 days, 23 participants aged 55-65 underwent baseline measurements, 14 days of -6° HDBR, and 7 days of recovery. Half did prescribed exercise thrice daily combining resistance and endurance exercise for a total duration of 1 h. Assessments included demographics, cardiorespiratory fitness, bone health, body composition, quality of life, mental health, cognition, muscle health and biomarkers. This study has yielded some published outcomes, with more forthcoming. Findings will enrich our comprehension of HDBR effects, guiding future strategies for astronaut well-being and aiding bedrest-bound older adults. By outlining evidence-based interventions, this research supports both space travellers and those enduring prolonged bedrest.

Influence of a Passive Tilt Test on the Proteomic Composition of the Blood of Healthy Humans.

In order to identify changes in the blood proteome of healthy volunteers after passive tilt test carried out on day 19 of head-down bed rest, a chromato-mass-spectrometric analysis of samples of dried blood spots was carried out. It was revealed that the body's response to the tilt test was characterized by a decrease in the level of HDL and kininogen-1. After the tilt test, we observed an increase in the level of vimentin, vitamin K-dependent protein C, Wnt signaling pathway proteins, proteins involved in autophagy and adaptive immune response, focal adhesion proteins, vascular damage marker S100A8, PEDF regulator, and some proteins of the heart: cardiac actin ACTC1 and transcription factor GATA4. The obtained results lay the foundation for future research in the framework of identifying the risks of developing cardiovascular changes in astronauts after space flights.

Repercusión de la colecistectomía laparoscópica en el paciente geriátrico / Repercussion of laparoscopic cholecistectomy on elderly patient

Introducción: Cada día resulta mayor la proporción de ancianos que asiste a los quirófanos. El manejo de estos pacientes ha ido evolucionando aparejadamente a las técnicas mínimamente invasivas, encaminadas a evitar la hospitalización, las complejas pruebas complementarias y los costosos tratamientos. Objetivo: Determinar los factores que repercuten en la hemodinamia del paciente geriátrico durante la colecistectomía laparoscópica. Material y Métodos: Se realizó un estudio prospectivo, longitudinal y analítico de 132 pacientes mayores de 60 años intervenidos por colecistectomía laparoscópica electiva, en el Hospital clínico-quirúrgico Julio Trigo López durante el período comprendido desde enero de 2014 hasta junio de 2016. Resultados: Predominó el grupo correspondiente a los 60 - 69 años de edad, el sexo femenino y el estado físico ASA II. El 75 por ciento de los pacientes no sufrió cambios hemodinámicos. Se presentó un 25 por ciento de variabilidades hemodinámicas predominantes en el grupo de 70-79 años de edad. La diferencia en la variabilidad hemodinámica entre los grupos etarios resultó altamente significativa. La hipertensión arterial (51,5 por ciento) y la taquicardia (27,3 por ciento) fueron las variaciones más frecuentes. Los factores determinantes en los cambios fueron dependientes del proceder quirúrgico: mayor presión intrabdominal posneumoperitoneo (22 por ciento) y Trendelenburg superior a 10 grados (93,9 por ciento). Conclusiones: Los factores determinantes en la hemodinamia fueron dependientes del acto quirúrgico. Se presentaron variaciones significativas entre los diferentes grupos etarios, sugiriendo cierta influencia del factor edad, pero la mayor longevidad no constituyó un aspecto decisivo. La colecistectomía laparoscópica es una valiosa alternativa terapéutica para los pacientes ancianos(AU)

Introduction: The number of elderly patients undergoing surgery is greater every day. The management of these patients has been evolving together with minimal invasive techniques, aimed at avoiding hospitalization, complex complementary tests, and expensive treatments. Objective: To determine the factors that have an effect on the hemodynamics of the geriatric patient during laparoscopic cholecystectomy. Material and Methods: A prospective, longitudinal, and analytic study was conducted in 132 patients older than 60 years of age who underwent elective laparoscopic cholecystectomy at the Julio Trigo López Clinical and Surgical Hospital during the period between January 2014 to June 2016. Results: Subjects aged 60 to 69 years, the female sex, and the physical state ASA II predominated in the study. 75% of these patients did not suffer hemodynamic changes. 25 percent of predominant hemodynamic variabilities were present especially in the group aged 70 to 79 years. The difference in hemodynamic variability between the age groups was highly significant. Arterial hypertension (51,5 percent and tachycardia (27,3 percent) were the most frequent variations. The determining factors in the changes were dependent on the surgical procedure: higher intra-abdominal pressure after pneumoperitoneum (22 percent) and Trendelenburg higher than 10 degrees (93.9 percent). Conclusions: The determining factors in hemodynamics were dependent on the surgical act. There were significant variations among the different age groups, suggesting a certain influence of the age factor, but the greatest longevity didn't constitute a decisive aspect. Laparoscopic cholecystectomy is a valuable therapeutic alternative for elderly patients(AU)

Colecistectomía transvaginal asistida por minilaparoscopia: con uso de instrumental convencional: experiencia inicial / Transvaginal cholecystectomy assisted with minilaparoscopy: with conventional instruments: initial experience

Describir la técnica quirúrgica en la colecistectomía transvaginal sin cicatriz visible con el uso de instrumental laparoscópico convencional, en el Hospital “Dr. Domingo Luciani”. Caracas. Se presenta caso de paciente femenina de 52 años de edad, con litiasis vesicular sintomática a quien se le practica colecistectomía transvaginal. Se realizó colecistectomía transvaginal sin complicaciones intraoperatorias. No se administraron analgésicos orales ni parenterales, el alta hospitalaria se dio a las 12 horas del procedimiento. Evolución satisfactoria de la paciente con un seguimiento de 30 días. La cirugía asistida por minilaparoscopia puede considerarse intermedia entre el NOTES, y la cirugía laparoscópica. El siguiente caso demuestra la factibilidad y seguridad del procedimiento realizado por cirujanos generales con entrenamiento laparoscópico y con el uso de instrumental convencional.

Describe the surgical technique in the transvaginal cholecystectomy without a scar using conventional laparoscopic instruments, in the “Dr. Domingo Luciani” Hospital. Caracas. Presents female patient 52 years old, with sintomatic gallstones who is practicing transvaginal cholecystectomy. Was performed transvaginal cholecystectomy without intraoperative complications. No analgesics were administered oral or parenteral, was discharged at 12 hours of the procedure. There was a satisfactory progress of the patient with a follow upof 30 days. Minilaparoscopy assisted surgery can be considered intermediate between NOTES, and laparoscopic surgery. The following case demonstrates the feasibility and safety of the procedure performed by general surgeons with laparoscopic training and the use of conventional instruments.

Prevalencia de alteraciones posturales en niños de Arica -Chile: efectos de un programa de mejoramiento de la postura / Prevalence of postural alterations and effects of a program to improve the posture in children from Arica-Chile

Los objetivos de este trabajo fueron calcular el índice de prevalencia de alteraciones posturales en una muestra de 120 alumnos (10,4 por ciento del universo total), de 4 años de edad de la ciudad de Arica y determinar el efecto de un programa de mejoramiento postural. Las alteraciones posturales más frecuentes corresponden a: inclinación de hombros (86 por ciento), escápula alada y escápula descendida (82 por ciento), proyección anterior de hombros (79 por ciento), pie plano (58 por ciento), columna lumbar hiperlordótica (51 por ciento) e inclinación de cabeza (50 por ciento). Posteriormente, se aplicó al grupo experimental un programa de ejercicio muscular y de reeducación postural, por un período de 8 meses. Al final del tratamiento se realizó un análisis post test a todos los sujetos del estudio. Los resultados en el grupo experimental muestran una disminución significativa de los índices iniciales de prevalencia, en todas las alteraciones en estudio. Los diferenciales de recuperación muestran diferencias significativas entre los grupos de estudio, con un 31 por ciento para inclinación de hombros, seguida de hiperlordosis lumbar con un 29 por ciento e inclinación de cabeza con 20 por ciento. La recuperabilidad más baja se observó en pie plano con un 7 por ciento (p≤0,05). El alto porcentaje de alteraciones posturales presentes en niños de 4 años, de la ciudad de Arica, podría ser producto de actitudes viciosas que, a futuro producen una estructuración inadecuada del cuerpo, entonces la aplicación de un programa de ejercitación muscular y de reeducación postural, dirigido por un equipo de Salud multiprofesional disminuirían significativamente estas alteraciones.

At present the educational institutions do not have an adequate system of Health to detect early changes in postural alteration in children. The aim of this study was to determine the most common postural changes in a sample of 120 students (10,4 percent of total universe), of 4 years old from Arica-Chile and to determine the effect of a program to improve the posture. The prevalence of the most frequent postural alterations relate to: inclination of shoulders (86 percent), winged scapula and descend scapula (82 percent), projection front shoulders (79 percent), flat feet (58 percent), lumbar hyperlordosis (51 percent) and inclination of head (50 percent). Subsequently in the experimental group was applied a program of exercise muscle and postural reeducation for a period of 8 months. At the end of treatment was applied a post-test to all children. The results in the experimental group showed a significant decrease in initial prevalence rates in all alterations. The differential recovery shows significant differences among the study groups, with 31 percent for inclination of shoulders, followed by lumbar hyperlordosis (29 percent) and inclination of head (20 percent). The recoverability lowest level was observed in flat feet with 7 percent (p≤0,05).The high percentage of postural disturbances in children aged 4 years in the city of Arica, could be the result of vicious attitudes that in the future produce an improper structuring of the body. Then the implementation of a program of exercise muscles and postural reeducation, led by a multiprofesional health team, decline rates of postural abnormalities present in children.

Pneumoperitônio com dióxido de carbono associado a três posiçöes para laparoscopia em cäes / Pneumoperitoneum using carbon dioxide associated with three positions for laparoscopy in dogs

Doze cäes foram submetidos ao pneumoperitônio com dióxido de carbono, em pressäo constante de 15mmHg, e posicionados em Trendelenburg, Trendelenburg reverso e decúbito horizontal. As variáveis de saturaçäo de oxigênio na hemoglobina, freqüência cardíaca, freqüência respiratória, pressäo arterial média, sistólica e diastólica, o pH, a pressäo parcial de CO2 e a pressäo parcial de O2 foram mensurados. Somente a freqüência cardíaca, a freqüência respiratória, o pH e a pressäo parcial de CO2 apresentaram diferença estatisticamente significativa em relaçäo ao tempo.