Fluid therapy for acute bowel obstruction: The value and its evaluation / 中国实用外科杂志

Bowel obstruction is one of the common acuteabdominal diseases in surgery. The primary task of itstreatment is to replace the effective circulating blood volumelost caused by loss of digestive juice and increased exudationof inflammation through fluid therapy,and stabilize thehemodynamic state of patients. Therefore,optimizing thetiming,amount and composition of fluid therapy according tothe pathophysiological characteristics of fluid loss in patientswith bowel obstruction,and evaluating the effect of fluidtherapy scientifically and reasonably by the cardiac preload,tissue perfusion and oxygen metabolism are the keys to improve fluid therapy for bowel obstruction.

Hemodinámica funcional: ¿Qué significa "ser respondedor"? / Functional hemodynamics: "Be responsive, what does this mean"?

The conventional analysis and approach to the physiology of the fluid responsiveness has traditionally been focused mainly on the physiology of heart-lung interactions, and on reviews of the technical, methodological, and epidemiological aspects of the dynamic parameters, which are translated into simple algorithms to assess fluid responsiveness and to guide fluid therapy.However, fundamental features of the dynamics of the peripheral circulation, heart-vasculature interaction, and blood volume distribution, are overlooked and sometimes not accounted for, motivating misconceptions about the cardiovascular system's response to fluid administration and fluid management, such as equating fluid loading with cardiac preload, a predictable interpretation whenever Starling's ventricular function curve is analyzed in isolation. This paper reexamines fluid responsiveness' rationale offering a broadened perspective on the circulatory phenomena involved in the physiological interaction between BV, cardiac preload and output, and stroke volume variation. Finally, implications relevant in physiological and clinical terms are discussed.

El análisis convencional y abordaje actual de la fisiología de la "respuesta a fluidos" (RF) ha estado focalizada principalmente sobre la fisiología de la interacción cardiopulmonar, y sobre aspectos técnicos, metodológicos y, epidemiológicos de los parámetros dinámicos, los cuales son traducidos en algoritmos simplificados para evaluar la RF y guiar la fluidoterapia. Sin embargo, aspectos fundamentales de la dinámica de la circulación periférica, el acoplamiento entre el corazón y la vasculatura, y la distribución del volumen sanguíneo son frecuentemente omitidos, motivando mal interpretaciones sobre la respuesta del sistema cardiovascular a la administración de fluidos, tal como equiparar la carga de fluidos con la precarga ventricular, una consecuencia predecible al interpretar la curva de función ventricular (Starling) de forma aislada. Así, esta revisión reexamina la rationale de la RF, ofreciendo una perspectiva ampliada sobre aquellos fenómenos circulatorios implicados en la interacción entre el volumen sanguíneo, la precarga ventricular, el gasto cardíaco y la variación del volumen sistólico. Finalmente, se analizarán las implicancias prácticas y conceptuales.

Comparison between noninvasive measurement of central venous pressure using near infrared spectroscopy with an invasive central venous pressure monitoring in cardiac surgical Intensive Care Unit.

Introduction: Central venous pressure (CVP) measurement is essential in the management of certain clinical situations, including cardiac failure, volume overload and sepsis. CVP measurement requires catheterization of the central vein which is invasive and may lead to complications. The aim of this study was to evaluate the accuracy of measurement of CVP using a new noninvasive method based on near infrared spectroscopy (NIRS) in a group of cardiac surgical Intensive Care Unit (ICU) patients. Methodology: Thirty patients in cardiac surgical ICU were enrolled in the study who had an in situ central venous catheter (CVC). Sixty measurements were recorded in 1 h for each patient. A total of 1800 values were compared between noninvasive CVP (CVPn) obtained from Mespere VENUS 2000 CVP system and invasive CVP (CVPi) obtained from CVC. Results: Strong positive correlation was found between CVPi and CVPn (R = 0.9272, P < 0.0001). Linear regression equation ‑ CVPi = 0.5404 + 0.8875 × CVPn (r2 = 0.86, P < 0.001), Bland–Altman bias plots showed mean difference ± standard deviation and limits of agreement: −0.31 ± 1.36 and − 2.99 to + 2.37 (CVPi–CVPn). Conclusion: Noninvasive assessment of the CVP based on NIRS yields readings consistently close to those measured invasively. CVPn may be a clinically useful substitute for CVPi measurements with an advantage of being simple and continuous. It is a promising tool for early management of acute state wherein knowledge of CVP is helpful.

Nitroglycerin reduces augmentation index and central blood pressure independent of effects on cardiac preload / 西安交通大学学报·英文版

Objective: To determine whether reduction in central pressure augmentation and central systolic blood pressure by nitroglycerine (NTG) results from effects on pre-load or is due to arterial dilation. Methods: We compared effects of NTG with those of lower body negative pressure (LBNP). Hemodynamic measurements were made at rest, during LBNP (10, 20 and 30 mmHg, each for 15 min) and after NTG (10, 30 and 100 μg/min, each dose for 15 min) in ten healthy volunteers. Cardiac pre-load, stroke volume and cardiac output were assessed by echocardiography. Central pressure augmentation and central systolic pressure were obtained by radial tonometry using a transfer function. Results: LBNP (20 mmHg) and NTG (30 μg/min) reduced pre-load (as measured by the peak velocity of the S wave in the superior vena cava) to a similar degree [by (26.8 ± 3.8)% and (23.9 ± 3.4)%, respectively]. Compared to LBNP, NTG reduced systemic vascular resistance [by (32.9± 7.5)%, P<0.01], decreased peripheral and central pressure augmentation [by (20.8 ± 3.4)% units and (12.9 ± 2.9)% units, respectively, each P<0.01]. Conclusion: These results suggest that a reduction in pre-load does not explain reduction in pressure augmentation and central systolic blood pressure by NTG and that these effects are mediated through arterial dilation.