Comparative study between suprasternal and apical windows: a user-friendly cardiac output measurement for the anesthesiologist.

INTRODUCTION: Transthoracic echocardiography is a safe and readily available tool for noninvasive monitoring of Cardiac Output (CO). The use of the suprasternal window situated at the sternal notch can be an alternative approach for estimating blood flow. The present study aimed to compare two methods of CO calculation. We compared the descending aorta Velocity-Time Integral (VTI) measurement from the suprasternal window view with the standard technique to determine CO that uses VTI measurements from the LVOT (Left Ventricular Outflow Tract) view. We also aimed to find out whether after basic training a non-echocardiographer operator can obtain reproducible measurements of VTI using this approach. METHODS: In the first part of the study, 26 patients without known cardiovascular diseases were evaluated and VTI data were acquired from the suprasternal window by a non-echocardiographer and an echocardiographer. Next, 17 patients were evaluated by an echocardiographer only and VTI and CO measurements were obtained from suprasternal and apical windows. Data were analyzed using the Bland and Altman method (BA), correlation and regression. RESULTS: We found a strong correlation between measurements obtained by a non-expert and an expert echocardiographer and detected that an inexperienced trainee can acquire VTI measurements from the suprasternal window view. Regarding agreement between CO measurements, data obtained showed a positive correlation and the Bland and Altman analysis presented a total variation of 38.9%. CONCLUSION: Regarding accuracy, it is likely that TTE (Transthoracic Echocardiogram) measurements of CO from the suprasternal window view are comparable to other minimally invasive techniques currently available. Due to its user-friendliness and low cost, it can be a convenient technique for obtaining perioperative hemodynamic measurements, even by inexperienced operators.

Effect of propranolol on the splanchnic and peripheral renin angiotensin system in cirrhotic patients.

AIM: To evaluate the effect of beta-blockade on angiotensins in the splanchnic and peripheral circulation of cirrhotic patients and also to compare hemodynamic parameters during liver transplantation according to propranolol pre-treatment or not. METHODS: Patients were allocated into two groups: outpatients with advanced liver disease(LD) and during liver transplantation(LT). Both groups were subdivided according to treatment with propranolol or not. Plasma was collected through peripheral venipuncture to determine plasma renin activity(PRA), Angiotensin(Ang) I, Ang II, and Ang-(1-7) levels by radioimmunoassay in LD group. During liver transplantation, hemodynamic parameters were determined and blood samples were obtained from the portal vein to measure renin angiotensin system(RAS) components. RESULTS: PRA, Ang I, Ang II and Ang-(1-7) were significantly lower in the portal vein and periphery in all subgroups treated with propranolol as compared to non-treated. The relationships between Ang-(1-7) and Ang I levels and between Ang II and Ang I were significantly increased in LD group receiving propranolol. The ratio between Ang-(1-7) and Ang II remained unchanged in splanchnic and peripheral circulation in patients under beta-blockade, whereas the relationship between Ang II and Ang I was significantly increased in splanchnic circulation of LT patients treated with propranolol. During liver transplantation, cardiac output and index as well systemic vascular resistance and index were reduced in propranolol-treated subgroup. CONCLUSION: In LD group, propranolol treatment reduced RAS mediators, but did not change the ratio between Ang-(1-7) and Ang II in splanchnic and peripheral circulation. Furthermore, the modification of hemodynamic parameters in propranolol treated patients was not associated with changes in the angiotensin ratio.

Comparative study between suprasternal and apical windows: a user-friendly cardiac output measurement for the anesthesiologist

Abstract Introduction Transthoracic echocardiography is a safe and readily available tool for noninvasive monitoring of Cardiac Output (CO). The use of the suprasternal window situated at the sternal notch can be an alternative approach for estimating blood flow. The present study aimed to compare two methods of CO calculation. We compared the descending aorta Velocity-Time Integral (VTI) measurement from the suprasternal window view with the standard technique to determine CO that uses VTI measurements from the LVOT (Left Ventricular Outflow Tract) view. We also aimed to find out whether after basic training a non-echocardiographer operator can obtain reproducible measurements of VTI using this approach. Methods In the first part of the study, 26 patients without known cardiovascular diseases were evaluated and VTI data were acquired from the suprasternal window by a non-echocardiographer and an echocardiographer. Next, 17 patients were evaluated by an echocardiographer only and VTI and CO measurements were obtained from suprasternal and apical windows. Data were analyzed using the Bland and Altman method (BA), correlation and regression. Results We found a strong correlation between measurements obtained by a non-expert and an expert echocardiographer and detected that an inexperienced trainee can acquire VTI measurements from the suprasternal window view. Regarding agreement between CO measurements, data obtained showed a positive correlation and the Bland and Altman analysis presented a total variation of 38.9%. Conclusion Regarding accuracy, it is likely that TTE (Transthoracic Echocardiogram) measurements of CO from the suprasternal window view are comparable to other minimally invasive techniques currently available. Due to its user-friendliness and low cost, it can be a convenient technique for obtaining perioperative hemodynamic measurements, even by inexperienced operators.

Hydroelectrolytic balance and cerebral relaxation with hypertonic isoncotic saline versus mannitol (20%) during elective neuroanesthesia.

BACKGROUND AND OBJECTIVES: Cerebral relaxation during intracranial surgery is necessary, and hiperosmolar therapy is one of the measures used to this end. Frequently, neurosurgical patients have sodium imbalances. The objective of the present study was to quantify and determine cerebral relaxation and duration of hydroelectrolytic changes secondary to the use of mannitol versus hypertonic isoncotic solution (HIS) during neurosurgery. METHODS: Cerebral relaxation and hydroelectrolytic changes were evaluated in 29 adult patients before de beginning of infusion, and 30 and 120 minutes after the infusion of equiosmolar loads of approximately 20% mannitol (250 mL) or HIS (120 mL). The volume of intravenous fluids infused and diuresis were recorded. A p < 0.05 was considered significant. RESULTS: A statistically significant difference in cerebral relaxation between both groups was not observed. Although several changes in electrolyte levels and acid-base balance with mannitol or HIS reached statistical significance only the reduction in plasma sodium 30 minutes after infusion of mannitol, mean of 6.42 ± 0.40 mEq.L(-1), and the increase in chloride, mean of 5.41 ± 0.96 mEq.L(-1) and 5.45 ± 1.45 mEq.L(-1) 30 and 120 minutes after infusion of HIS, caused a transitory dislocation of serum ion levels from normal range. The mannitol (20%) group had a significantly greater diuresis at both times studied compared with HIS group. CONCLUSIONS: A single dose of hypertonic isoncotic saline solution [7.2% NaCl/6% HES (200/0.5)] and mannitol (20%) with equivalent osmolar loads were effective and safe in producing cerebral relaxation during elective neurosurgical procedures under general anesthesia.

Angiotensin-converting enzyme inhibition changes the metabolic response to neuroglucopenic stress.

Neuroglucopenia induced by 2-deoxy-D-glucose (2DG) activates hypothalamic glucoreceptors leading to increased hepatic glucose production and insulin inhibition. This response is similar to what is observed with intravenous injection of angiotensin II (Ang II). However, the involvement of an angiotensin-converting enzyme inhibitor on neuroglucopenia has not been investigated. The aim of this study was to determine the effects of chronic enalapril treatment on plasma glucose, insulin and lipid levels in response to neuroglucopenia. Male Holtzman rats (120-170 g) were chronically treated with enalapril (10 mg/kg per day) in the drinking water for two weeks. On the day of experiment the animals received an i.v. enalapril final dose one hour before the neuroglucopenic stress by 2DG infusion (500 mg/kg), and blood samples were drawn before and 5, 10, 20, 30 and 60 minutes following infusion. The hyperglycaemic response to 2DG was not significantly changed by enalapril treatment. The enalapril-treated group exhibited a peak of plasma insulin higher than controls. Plasma triglyceride showed a significant increase only in the enalapril group after neuroglucopenic stress (p < 0.05).These data show that chronic enalapril treatment changes insulin and triglyceride responses to neuroglucopenia, suggesting an effect on glucose-induced insulin secretion and the storage of triglycerides.

Anesthetic conduct in cesarean section in a parturient with unruptured intracranial aneurysm.

BACKGROUND AND OBJECTIVES: The anesthetic management of a parturient with unruptured intracranial aneurysm scheduled to undergo cesarean section is interesting, since it has several particularities associated with pregnancy-related physiologic changes that are associated with the risk of aneurismal rupture during the anesthetic procedure. Studies on this subject are rare in the literature and, therefore, the dissemination of those cases is important. CASE REPORT: This is a 31-year old female at term with unruptured intracranial aneurysm scheduled for cesarean section under epidural block. The procedure evolved without maternal or fetal intercurrences. CONCLUSIONS: Evidence-based recommendations for obstetric anesthesia in patients with unruptured intracranial aneurysm are lacking. Experimental or clinical data confirming or refuting general anesthesia or regional blocks in this context do not exist. Thus, the decision of which technique should be used is individual, considering the risks and benefits of each procedure and the experience of the anesthesiologist.

Relationship between angiotensin-(1-7) and angiotensin II correlates with hemodynamic changes in human liver cirrhosis.

AIM: To measure circulating angiotensins at different stages of human cirrhosis and to further evaluate a possible relationship between renin angiotensin system (RAS) components and hemodynamic changes. METHODS: Patients were allocated into 4 groups: mild-to-moderate liver disease (MLD), advanced liver disease (ALD), patients undergoing liver transplantation, and healthy controls. Blood was collected to determine plasma renin activity (PRA), angiotensin (Ang) I, Ang II, and Ang-(1-7) levels using radioimmunoassays. During liver transplantation, hemodynamic parameters were determined and blood was simultaneously obtained from the portal vein and radial artery in order to measure RAS components. RESULTS: PRA and angiotensins were elevated in ALD when compared to MLD and controls (P < 0.05). In contrast, Ang II was significantly reduced in MLD. Ang-(1-7)/Ang II ratios were increased in MLD when compared to controls and ALD. During transplantation, Ang II levels were lower and Ang-(1-7)/Ang II ratios were higher in the splanchnic circulation than in the peripheral circulation (0.52 +/- 0.08 vs 0.38 +/- 0.04, P < 0.02), whereas the peripheral circulating Ang II/Ang I ratio was elevated in comparison to splanchnic levels (0.18 +/- 0.02 vs 0.13 +/- 0.02, P < 0.04). Ang-(1-7)/Ang II ratios positively correlated with cardiac output (r = 0.66) and negatively correlated with systemic vascular resistance (r = -0.70). CONCLUSION: Our findings suggest that the relationship between Ang-(1-7) and Ang II may play a role in the hemodynamic changes of human cirrhosis.

Anestesia geral para cesariana / General anesthesia for cesarean section

As técnicas neuroaxiais são a primeira escolha anestésica para cesariana. Elas permitem a participação da mãe na hora do nascimento e são mais seguras em vários aspectos. Em algumas situações, entretanto, podem falhar ou ter contraindicações absolutas e relativas. Nestes casos, a anestesia geral passa a ter mais benefícios que riscos. As principais dificuldades da anestesia geral para cesariana são o manejo de vias aéreas (potencialmente mais difícil), alto risco de aspiração pulmonar, alta incidência de consciência intraoperatória da gestante e de depressão neonatal no pós-parto imediato. Esta revisão examina conhecimentos recentes desses tópicos, descreve benefícios e riscos de novas drogas e propõe um protocolo clínico de anestesia geral para cesárea.

The neuroaxial techniques are the first choice for cesarean section. They allow mother?s participation during the birth and are safer in many aspects. Neuroaxial techniques, however, may fail and have absolute and relative contraindications, situations in which a cesarean under general anesthesia would have benefits outweigh the risks. The main difficulties of general anesthesia for cesarean section are concerning to potentially difficultairway, increased risk of pulmonary aspiration and higher incidence of mother?s intraoperative awareness and neonatal depression in the immediate postpartum period. This review examines the current knowledge of these topics, describes the benefits and risks of new drugs and proposes a protocol of general anesthesia for cesarean section.

Conduta anestésica em cesariana em gestante com aneurisma intracraniano não roto / Conducta anestésica en cesárea en embarazada con aneurisma cerebral íntegro / Anesthetic conduct in cesarean section in a parturient with unruptured intracranial aneurysm

Justificativa e objetivos: O manuseio anestésico para cesariana programada em gestante com aneurisma intracraniano não roto é particularmente interessante, pois apresenta diversas particularidades relacionadas às alterações fisiológicas da gestação acrescida dos riscos de ruptura do aneurisma durante o procedimento anestésico. A literatura é escassa nesse assunto, sendo assim importante a divulgação dos casos. .

Background and objectives: The anesthetic management of a parturient with unruptured intracranial aneurysm scheduled to undergo cesarean section is interesting, since it has several particularities associated with pregnancy-related physiologic changes that are associated with the risk of aneurismal rupture during the anesthetic procedure. Studies on this subject are rare in the literature and, therefore, the dissemination of those cases...

Justificativa y objetivos: El manejo anestésico para la cesárea programada en embarazada con aneurisma cerebral íntegro es particularmente interesante, porque presenta diversas particularidades relacionadas con las alteraciones fisiológicas del embarazo y por añadidura, con los riesgos de ruptura del aneurisma durante el procedimiento anestésico. La literatura es parca en ese asunto, siendo muy importante la divulgación...

Anestesia para cirurgia não-obstétrica durante a gravidez / Anesthesia for nonobstetric surgery during pregnancy

Anestesiologistas em cada subespecialidade encontram, com variada regularidade, pacientes se apresentando para cirurgias durante o curso de uma gravidez. Até 2% de todas as mulheres grávidas são submetidas à cirurgia não-obstétrica durante a gravidez, que pode ser indicada em qualquer idade gestacional. O estágio da gestação e o procedimentocirúrgico indicado parecem ter influências prognósticas maternas e fetais. Em geral, o segundo estágio é tido como o mais oportuno para aqueles procedimentos que não podem esperar até depois do parto, porque a organogênese já está completa e o risco de parto prematuro é mais baixo do que no terceiro trimestre. A escolha da anestesia para a cirurgia não-obstétrica em grávidas possui características clínicas únicas, já que envolve dois pacientes e a fisiologia específica da gravidez. O objetivo final é promover uma anestesia segura para a mãe, enquanto simultaneamente minimiza-se o risco de comprometimento fetal. Manutenção da perfusão útero-placentária e adequada oxigenação materna preservam a oxigenação fetal e são de importância máximapara qualquer anestesia durante a gravidez.

Anesthesiologists in every subspecialty encounter, with varying regularity, patients presenting for surgery during the course of pregnancy. About 2% of pregnant women undergo nonobstetric surgery during pregnancy, which may be required at any gestational age. Timing and indications for the surgical procedure seem critical to the maternal and fetal outcome. In general, the second trimester is regarded as the most opportune for those procedures which cannot be delayed until after delivery, as organogenesis is complete and the risk of preterm labor is lower than in the third trimester. The choice of anesthesia for nonobstetric surgery in pregnancy have unique clinical concern, since involves two patients and physiology specific to pregnancy. The ultimate goal is to provide safe anesthesia to the mother while simultaneously minimizing the risks to the fetus. Maintenance of uterine perfusion and adequate maternal oxigenation preserves fetal oxygenation and are of utmost importance to any anesthesia during pregnancy.