Noradrenaline and dobutamine effects on the volume expansion with normal saline in rabbits subjected to hemorrhage

PURPOSE: To evaluate the effects of dobutamine (DB), noradrenaline (NA), and their combination (NADB), on volume retention in rabbits submitted to hemorrhage. METHODS: Thirty six rabbits were randomly divided into 6 groups: SHAM, Control, Saline, DB, NA, DB+NA. All the animals, except for SHAM, were subjected to hemorrhage of 25% of the calculated blood volume. Control animals were replaced with their own blood. The other groups received NSS 3 times the volume withdrawn. The intravascular retention, hematocrit, diuresis, central venous pressure, mean arterial pressure, NGAL, dry-to-wet lung weight ratio (DTWR) and the lung and kidney histology were analyzed. RESULTS: Replacement with NSS and NA, DB or NA+DB did not produce differences in the intravascular retention. After hemorrhage, the animals presented a significant decrease in the MAP and CVP, which were maintained until volume replacement. Regarding NGAL, dry-to-wet-lung-weight ratio, lung and kidney histology, there were no statistical differences between the groups. CONCLUSION: The use of noradrenaline, dobutamine or their combination did not increase the intravascular retention of volume after normal saline infusion.(AU)

Optimizing perioperative hemodynamics: what is new?

PURPOSE OF REVIEW: Using perioperative goal-directed therapy (GDT) or peroperative hemodynamic optimization significantly reduces postoperative complications and risk of death in patients undergoing noncardiac major surgeries. In this review, we discuss the main changes in the field of perioperative optimization over the last few years. RECENT FINDINGS: One of the key aspects that has changed in the last decade is the shift from invasive monitoring with pulmonary artery catheters (PACs) to less or minimally invasive monitoring systems. The evaluation of intravascular fluid volume deficits has also changed dramatically from the use of static indices to the assessment of fluid responsiveness using either dynamic indices or functional hemodynamic. Finally, attention has been directed toward more restrictive strategies of crystalloids as maintenance fluids. SUMMARY: GDT is safe and more likely to tailor the amount of fluids given to the amount of fluids actually needed. This approach includes assessment of fluid responsiveness and, if necessary, the use of inotropes; moreover, this approach can be coupled with a restrictive strategy for maintenance fluids. These strategies have been increasingly incorporated into protocols for perioperative hemodynamic optimization in high-risk patients undergoing major surgery, resulting in more appropriate use of fluids, vasopressors, and inotropes.

Curso de Atualização em Emergências Médicas: aula 19: reposição volêmica / Course of Updating in Medical Emergencies: class 19: volemic replacement

Hipovolemia em pacientes agudamente enfermos é um evento relativamente comum, e com importância clínica para o paciente, sendo a rápida e vigorosa reposição volêmica capaz de diminuir o risco de morte inicialmente e de evolução para falência renal na sequência. Neste artigo revisaremos os diferentes tipos de expansores, suas propriedades, vantagens e desvantagens. Os cristaloides se mantêm como preferência pela segurança, eficácia e baixo custo, com a desvantagem da importante formação de edema. As soluções hipertônicas têm indicação no atendimento pré-hospitalar por ser eficaz, porém com estabilização hemodinâmica de caráter efêmero, e pela possibilidade de distúrbios eletrolíticos. Estudos clínicos randomizados não demonstraram superioridade da albumina aos cristalóides e assim como são de custo alto ficam como segunda alternativa ou casos selecionados.

Hypovolemia in critically ill patients is a common event in intensive care patients, and it is clinically relevant for the patient. The fluid replacement is used to try to reduce risk of death and evolution to renal failure. In this article we review different types of expansors, their properties, advantages and disadvantages. Crystalloids are indicated for the safety, efficacy and low cost, the only disadvantage is oedema formation. Hypertonic crystalloid are indicated only in prehospitalar fluid resuscitation, because of your efficacy, but for a short period of time, and the possibility of hydroeletrolitic derangements. There is no evidence that colloids are more effective than crystalloids in reducing mortality in people who are critically ill or injured, and the high cost, turn them the second choice.

Safe limits for aspirate volume under wet liposuction.

BACKGROUND: Hypovolemia is a hemodynamic disorder occasionally associated with liposuction. The purpose of this study is to settle a safe limit for the volume of aspirate under wet liposuction relating this volume to body weight. The criteria used to establish this limit were based on the Advanced Trauma Life Support (ATLS). METHODS: Thirty patients underwent wet liposuction and were submitted postoperatively to a 24-h noninvasive monitoring control of vital signs. Tachycardia (over 100 bpm) and systolic hypotension (below 100 mmHg) were recorded as well as urinary volume and respiratory rate. Hemoglobin, hematocrit, and leukocyte counts were determined preoperatively and also determined 1 and 6 h postoperatively. RESULTS: The volume of aspirate ranged from 1,480 to 3,980 ml (2.6% to 6.9% of body weight). Hemoglobin count decreased around 6 h postoperatively compared to the immediate preoperative period (p<0.0001). An increase of leukocytes was observed around 6 h postoperatively when compared with the preoperative period-nearly 30 min before surgery (p<0.0001). No association was found between hemoglobin or leukocyte counts and volume of aspirate. In 15 patients, tachycardia and/or hypotension were recorded postoperatively. These hemodynamic disorders were associated to volumes of aspirate higher than 5% of body weight. CONCLUSIONS: Under wet liposuction, a volume of aspiration not superior to 5% of body weight is proposed as a safe limit. It has been found as a clue to avoid hypovolemia and subsequently the shock. This statement is in agreement with ATLS guidelines.

The volume of lactated Ringer's solution required to maintain preload and cardiac index during open and laparoscopic surgery.

BACKGROUND: Recent studies have emphasized the importance of perioperative fluid restriction. However, fluid restriction regimens may increase the likelihood of insufficient perioperative fluid administration or may result in excess intravascular crystalloid replacement. We postulate that the use of transesophageal echocardiography may reduce the amount of crystalloid administered during open and laparoscopic colorectal surgery. METHODS: Fifteen ASA I and II patients scheduled for open colorectal surgery, and 15 patients scheduled for laparoscopic surgery were studied. Lactated Ringer's solution was infused during the procedures. Left ventricular end diastolic volume index (LVEDVI) and cardiac index were assessed throughout surgery and used to guide the rate of lactated Ringer's solution administration. Statistical analysis was performed with Student's t-test for unpaired samples. RESULTS: The rate of crystalloid administration required to maintain baseline LVEDVI and cardiac index was 5.9 +/- 2 mL x kg(-1) x h(-1) for open surgery and 3.4 +/- 0.8 mL x kg(-1) x h(-1) for laparoscopic surgery (P < 0.01). This slower rate for laparoscopic surgery was offset by the longer surgical duration. CONCLUSION: The rate of crystalloid solution to maintain baseline LVEDVI and cardiac index was greater in open surgery than laparoscopic surgery, and lower than commonly recommended for colorectal surgery.