Clinical Application of Near-Infrared Spectroscopy in Neonates

The incidence of cerebral palsy has not decreased despite advances in neonatal care. Preterm infants are at a high risk of cerebral palsy. Moreover, preterm infants might experience permanent neurological sequelae due to injury in the preterm brain. Although the etiology of preterm brain injury is not fully understood, preterm brain injury is strongly associated with abnormal cerebral perfusion and oxygenation. Monitoring systemic blood pressure or arterial oxygen saturation using pulse oximetry is not enough to guarantee proper cerebral perfusion or oxygenation. Early detection of improper cerebral perfusion can prevent irreversible cerebral damage. To decrease brain injury through the early detection of under-perfusion and deoxygenation, other diagnostic modalities are needed. Near-infrared spectroscopy can continuously and noninvasively monitor regional oxygen saturation (rSO₂), which reflects the perfusion and oxygenation status of tissues at bedside. Near-infrared spectroscopy represents a balance between tissue oxygen supply and demand. Cerebral rSO₂ monitoring has been used most frequently in neonatal cardiac surgery to monitor cerebral oxygenation and prevent hypoxic damage or shock. Recently, cerebral, renal, or splanchnic rSO₂ in neonates is frequently monitored. The progression of a disease, brain injury, and death can be prevented by detecting changes in rSO₂ values using near-infrared spectroscopy. In this article, the basic principles, usefulness, and applications of near-infrared spectroscopy in neonates are discussed.

Descending Aorta Blood Flow Characteristics before the Development of Necrotizing Enterocolitis in Preterm Neonates

PURPOSE: To investigate the hemodynamic risk factors for necrotizing enterocolitis (NEC), we analyzed the characteristics of descending aorta (DA) blood flow in preterm neonates, who later developed NEC. METHODS: This was an observational case-control study on 53 preterm neonates at a tertiary referral center. Clinical and echocardiographic data were collected from 23 preterm neonates with NEC (NEC group), and compared with those of 30 preterm neonates without NEC (control group). Echocardiography was done at a median (interquartile range) of 5 (3–9) days after birth and 2 (1–2.5) days before the diagnosis of NEC. RESULTS: Basic clinical characteristics including gestational age, birth weight, Apgar score, breast feeding status, use of umbilical catheters, and mode of invasive ventilator care were similar between the groups. Compared with the control group, the lowest diastolic velocity of DA was significantly decreased, whereas the diastolic reverse flow and the ratio of diastolic reverse to systolic forward flows were significantly increased in the NEC group. In addition, the resistive index (RI) of DA was significantly increased in the NEC group and showed a positive association with the development of NEC. Multivariate logistic regression analysis showed that increasing RI of DA was an independent risk factor for the development of NEC (P=0.008). CONCLUSION: Significant changes in DA flow characteristics including decreased diastolic velocity and increased diastolic reverse flow along with increased peripheral vascular resistance were observed before the development of NEC in preterm neonates. These findings may help clinicians stratify in advance neonates at a risk of developing NEC and may help improve outcomes in these neonates.

Acquired portosystemic collaterals: anatomy and imaging / Colaterais portossistêmicas adquiridas: aspectos anatômicos e imaginológicos

Abstract Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common-increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations.

Resumo As vias colaterais ou shunts portossistêmicos são trajetos vasculares calibrosos de comunicação patológica entre a circulação esplâncnica e a sistêmica. Suas causas são multifatoriais, compartilhando um mecanismo de elevação da pressão venosa portal, a qual promove o desvio do fluxo sanguíneo do trato gastrintestinal para a circulação sistêmica. Múltiplas vias de colaterais estão descritas na literatura, sendo congênitas ou adquiridas. Ambas as causas, congênitas e adquiridas, resultam na redistribuição de volume vascular do trato gastrintestinal de veias sistêmicas e um aumento concomitante na pressão venosa portal. Os objetivos deste ensaio são: 1) discutir as características anatômicas e de imagem dos shunts portossistêmicos; 2) fornecer uma revisão robusta (com ilustrações e desenhos esquemáticos) para detectar e reconhecer os shunts portossistêmicos adquiridos. A importância do seu reconhecimento recai sobre o fato que, em alguns casos, eles são os únicos sinais que predizem a presença de hipertensão portal, sendo a avaliação do radiologista de grande valia na escolha de tratamentos endovasculares e na detecção de suas complicações.

Abdomen y corazón ¿El primer paso del síndrome cardiorrenal? / Abdomen and heart The first step of the cardiorenal syndrome?

A pesar de los grandes avances en la cardiología en el siglo XX y XXI, la insuficiencia cardiaca sigue suponiendo la principal causa de hospitalización en las personas ancianas y presentando un pronóstico ominoso. Además, a pesar de los múltiples estudios sobre nuevas dianas farmacológicas, apenas hemos avanzado en el campo del tratamiento, tal vez porque aún existen lagunas en su fisiopatología. No debemos olvidar que la insuficiencia cardiaca es un compendio de signos y síntomas que engloban múltiples órganos y sistemas. Mucho se está investigando sobre la relación entre riñón y corazón en forma de síndrome cardiorrenal. Algo cada vez más en boga es el papel del abdomen en la disfunción orgánica de la insuficiencia cardiaca. En ese sentido, el sistema venoso contiene el 70 por ciento del volumen sanguíneo, siendo almacenado en su mayor parte dentro de las vísceras abdominales. Un aumento del tono simpático supone aumento intenso del retorno venoso tan importante como para aumentar las presiones de llenado y justificar una descompensación cardíaca. La congestión sistémica determina un aumento en la presión intraabdominal que está correlacionada con la disfunción renal en la insuficiencia cardíaca avanzada. La hipoperfusión tisular intestinal supone microtraslocación bacteriana promoviendo el status proinflamatorio típico de este síndrome. La visión holística e integrada de la insuficiencia cardiaca puede suponer un avance tanto en la estratificación del riesgo como en las estrategias terapéuticas. Grandes pasos se están dando en este sentido con estudios sobre la ultrafiltración, paracentesis, diálisis peritoneal, suero hipertónico o fármacos adsorbentes del sodio.(AU)

Despite the great progress in Cardiology during the last century, heart failure keeps being the main cause of hospitalization among elderly, with an awful prognosis. In spite of multiple studies about drug targets, we have hardly made progress regarding the treatment, maybe because there are gaps concerning physiopathology. Heart failure is a set of signs and symptoms encompassing multiple organs and systems. Lots of studies about cardiorenal syndrome are being published. In this sense, abdominal contribution to organic dysfunction in heart failure is becoming a rising topic. Therefore, venous system contains 70 percent of the total blood volume, mostly in splanchnic capacitance veins. Sympathetic stimulation suppose an important shift of blood from splanchnic veins to effective circulatory volume, rising increasing filling pressures and justifying acute decompensated heart failure. Systemic congestion may lead to a state of increased intra-abdominal pressure which is correlated with renal dysfunction in advanced heart failure. Tisular hypoperfusion leads to bacterial translocation triggering systemic inflammation typical of heart failure. This holyistic vision may suppose an important progress on risk stratification and treatment strategies. Among those under investigation are ultrafiltration, paracentesis peritoneal dialyisis, hypertonic saline or oral sodium binders.(AU)

Effects of portal hyperperfusion on partial liver grafts in the presence of hyperdynamic splanchnic circulation: hepatic regeneration versus portal hyperperfusion injury

In cirrhotic patients undergoing liver transplantation, reperfusion of a liver graft typically increases portal venous blood flow (PVF) because of a decrease in resistance in the liver graft to the PVF and underlying hyperdynamic splanchnic circulation, which develops due to liver cirrhosis complicated by portal hypertension and persists even after successful liver transplantation. If the liver graft has enough capacity to accommodate the increased PVF, the shear stress inflicted on the sinusoidal endothelial cells of the graft promotes hepatic regeneration; otherwise, small-for-size syndrome (SFSS) develops, leading to poor graft function and graft failure. In particular, a partial graft transplanted to patients undergoing living donor liver transplantation has less capacity to accommodate the enhanced PVF than a whole liver graft. Thus, the clinical conditions that the partial graft encounters determine either hepatic regeneration or development of SFSS. Consistent with this, this review will discuss the two conflicting effects of portal hyperperfusion (hepatic regeneration vs. portal hyperperfusion injury) on the partial grafts in cirrhotic patients suffering from hyperdynamic splanchnic circulation, in addition to normal physiology and pathophysiology of hepatic hemodynamics.

Scintigraphic study of the splenic circulation in rats / Estudo cintilográfico da circulação esplênica em ratos

Objective: To evaluate the splenic parenchymal blood distribution through scintigraphic study. Methods: Thirty Wistar rats were randomly divided into six groups (n = 5). Group 1 (spleen - 30 minutes) and Group 2 (spleen - 90 minutes) underwent laparotomy with direction of blood flow to the spleen by ligature of the aorta near the iliac bifurcation and splanchnic vessels, keeping blood flow only in the splenic artery; Group 3 (spleen and stomach - 30 minutes) and Group 4 (spleen and stomach - 90 minutes) underwent laparotomy with direction of blood flow to the spleen and stomach by ligature of the aorta near the iliac bifurcation and splanchnic vessels, maintaining the flow through the splenic, gastric and splenogastric vessels; Group 5 (control - 30 minutes) and Group 6 (control - 90 minutes) underwent laparotomy and ligation of the aorta near the iliac bifurcation, keeping the flow to the abdominal organs. After arterial ligation, the animals received an injection of 0.2 ml of sodium pertechnetate in the aorta. Scintigraphic images were taken and the animals had their spleens removed for radioactivity counting with an automatic counter device. Results: There was no difference in the amounts of radiation from the spleen between groups, indicating retention of the radioisotope by the spleen, even after the period of 90 minutes. Conclusion: The blood flow through the spleen is not continuous. The blood diffuses through the splenic parenchyma and its venous drainage is slow, not following a predictable sequence. .

Objetivo: avaliar a distribuição sanguínea vasculoparenquimatosa do baço, por meio de estudo cintilográfico. Métodos: trinta ratos da raça Wistar foram distribuídos aleatoriamente em seis grupos (n=5). Grupo 1 (baço - 30 minutos) e Grupo 2 (baço - 90 minutos): submetidos à laparotomia com direcionamento do fluxo sanguíneo para o baço, por meio de ligadura da aorta próxima à bifurcação das ilíacas e dos vasos esplâncnicos, mantendo apenas a artéria esplênica; Grupo 3 (baço e estômago - 30 minutos) e Grupo 4 (baço e estômago - 90 minutos): submetidos à laparotomia com direcionamento do fluxo sanguíneo para baço e estômago, por meio de ligadura da aorta próxima da bifurcação das ilíacas e dos vasos esplâncnicos, com manutenção do fluxo pelas artérias esplênica, gástrica e vasos esplenogástricos; Grupo 5 (controle - 30 minutos) e Grupo 6 (controle - 90 minutos): submetidos à laparotomia e ligadura da aorta próxima à bifurcação das ilíacas, mantendo o fluxo para os órgãos abdominais. Após as ligaduras arteriais, os animais receberam injeção de 0,2ml de pertecnetato de sódio na aorta. Foram realizadas imagens cintilográficas, e os animais tiveram o baço retirado para contagem radioativa em aparelho contador automático. Resultados: não houve diferença nos valores de radiação do baço entre os grupos, indicando retenção do radioisótopo pelo baço, mesmo após o período de 90 minutos. Conclusão: o fluxo sanguíneo através do baço não é contínuo. O sangue difunde-se pelo parênquima esplênico e sua drenagem venosa é lenta, não seguindo sequência previsível. .

Vascular endothelial growth factor's participation in splanchnic hyperdynamic circulation in portal hypertension / 中华肝胆外科杂志

Objective To detect the variation of vascular endothelial growth factor (VEGF) in the splanchnic vessels under portal hypertension (PHT) and explore its mechanism and influence on the process of hyperdynamic circulation.Methods In humans,the level of VEGF pathway related proteins were detected in the splenic artery of PHT patients in clinical trials.In animal experiments,the following parameters were observed for rats in the control group (group N,n =7) and the CCl4 induced portal hypertension group (group PHT,n=7):portal vein diameter,portal vein blood flow velocity (PBV),portal vein blood flow (PBF),portal vein pressure (PP),norepinephrine (NE) reactivity in the isolated mesenteric artery microcirculation,contractile reactivity and degree of endothelial ni tric oxide synthase (eNOS) activation in the mesenteric artery by selectively inhibiting the VEGF signal pathway with SU5416.In cell experiments,primary culturing of arterial endothelial cells in vitro were used to verify the effects of VEGF on eNOS activation.Results The results showed that VEGF expression levels in the splenic artery of PHT patients significantly increased.In animal experiments,there was not a significant difference in portal vein diameter between group N and group PHT.How ever,the PBV and PBF of group PHT were lower than those of group N,and SU5416 had no clear effect on PBV and PBF in group PHT.PP of group PHT was much higher than that of group N,and SU5416 had little influence on reducing PP in group PHT.The contractile response of mesenteric artery microcirculation to NE in group PHT decreased significantly,EC50 increased a lot,and SU5416 improved this hypoergia partially.The protein levels of VEGF,VEGFR-2,eNOS,and p-eNOS in the mesentery artery of group PHT raised quite a lot compared to group N,and SU5416 decreased the protein level of VEGFR-2 and activation of eNOS significantly.Experiments in vitro confirmed that VEGF could promote the activation of eNOS.Conclusion The excessive VEGF produced in visceral arteries under PHT may participate in the process of hyperdynamic circulation partially through promoting the synthesis and activation of eNOS and then reducing visceral arteries' response to NE.

A Case of Ischemic Duodenal and Jejunal Enteritis in a Patient with Chronic Splanchnic Disease / 대한내과학회지

Gastrointestinal ischemia happens by splanchnic artery stenosis, thrombus, or physiological vasoconstriction during a low-blood-stream state. However, even if arterial stenosis exists in the upper gastrointestinal tract, ischemic injury is very rare due to rich collateral circulation. The authors experienced 92-year-old female patient with vomiting, epigastric pain, and hematemesis. An electrocardiogram showed paroxysmal atrial fibrillation. The patient had diffuse and segmental mucosal edema, erythema, and hemorrhage in the second part of the duodenum on esophagogastroduodenoscopy (EGD). On abdomen computed-tomography angiography, stenosis of the celiac and superior mesenteric arteries was observed, and segmental concentric wall thickness was seen from the proximal second portion of the duodenum to the proximal jejunum. The patient was treated with PPI and fluid therapy for one week. At follow-up EGD, the mucosa had improved compared with the previous EGD examination. In conclusion, ischemic injury rarely affects the duodenum and jejunum; however, it can develop in the presence of inducing factors.

Ischemia-reperfusion histopathology alterations of the rabbit intestinal wall with and without exclusion of the collateral mesenteric circulation supply / Alterações histopatológicas da parede intestinal de coelhos na isquemia-reperfusão com e sem exclusão da circulação mesentérica colateral

PURPOSE: To evaluate the histopathology alterations of the intestinal mucosa of rabbits submitted to different times of mesenteric artery ischemia and reperfusion with and without celiac artery collateral circulation supply. METHODS: Two groups of eight male New Zealand white rabbits (weight 2.2-3.5 kg) were used in this study. In the Group 1 animals, the proximal mesenteric artery was occluded for 60 min with an atraumatic vascular clamp, followed by reperfusion for 60 min. In the Group 2 animals the small bowel and mesentery were cut 30cm and 60cm far from the gastroduodenal pyloric transition before the proximal mesenteric artery occlusion. Small bowel biopsies were obtained before ischemia (control), after 30 min and 60 min of mesenteric ischemia and at 30 and 60 min. of mesenteric artery reperfusion. RESULTS: In the Group I animals, the followings histopathology grade results were observed: t1, mean 0.4 + 0.29; t2, mean 1.9 ± 0.38; t3, 1.9 ± 0.33; t4, 1.2 ± 0.36 and t5, 1.2 ± 0.32. Differences between t0 and t2 and between t3 and t4 were statistically significant (p<0.05). Differences between t2 and t3 and t4 and t5 were not significant (p>0.5). In the Group II animals, it was observed: t1, mean 1.6 ± 0.33; t2, 2.4 ± 0.36; t3, 3.0 ± 0.35; t4 3.4 ± 0.31; t5, 3 ± 031. Differences between t0 and t1, t1 and t2, and t2 and t3 were significant (p<0.05). Differences between histopathology grades results of samples t1 to t5 in Group 1 and 2 were statistically significant (p<0.5). CONCLUSION: Microscopic examination of the biopsies revealed significant evidence of worse small bowel wall ischemia-reperfusion lesions by exclusion of the celiac artery collateral circulation supply.

OBJETIVO: Avaliar as alterações histopatológicas da mucosa intestinal de coelhos submetidos à isquemia-reperfusão com e sem exclusão da circulação mesentérica colateral. MÉTODOS: Foram estudados dois grupos de oito coelhos Nova Zelândia machos com pesos variáveis entre 2,2 e 3,5 kg de peso corpóreo. Nos animais do Grupo 1, a artéria mesentérica proximal foi ocluida por pinçamento atraumático durante 60 min, seguido de reperfusão por 60 min. No Grupo 2 o intestino delgado e o mesentério foram seccionados 30 cm e 60 após a transição pilórica gastroduodenal antes da oclusão da artéria mesentérica cranial. Biópsias da parede intestinal foram obtidas antes da isquemia (controle), após 30 e 60 min. de isquemia. RESULTADOS: No Grupo I foram observados os seguintes graus de lesões: t1,média de 0.4 + 0.29; t2, média 1.9 ± 0.38; t3, 1.9 ± 0.33; t4, 1.2 ± 0.36 e t5, 1.2 ± 0.32. As diferenças entre t0 e t2 e entre t3 e t4 foram significantes (p<0.05). As diferenças entre t2 e t3 e t4 e t5 não foram significantes (p>0.5). No Group II observou-se: t1, média de 1.6 ± 0.33; t2, 2.4 ± 0.36; t3, 3.0 ± 0.35; t4 3.4 ± 0.31; t5, 3 ± 031. As diferenças entre t0 e t1, t1 e t2, e t2 e t3 foram significantes (p<0.05). As diferenças entre os resultados histopatológicos das biopsies de t1 a t5 dos Grupos 1 e 2 foram significantes (p<0.5). CONCLUSÃO: A exclusão da circulação mesentérica colateral agravou significantemente a degeneração histopatológica na isquemia-reperfusão da parede intestinal.

Tratamiento quirúrgico del aneurisma del tronco celíaco, reporte de un caso / Surgical treatment of aneurysm of the celiac trunk: case report

Los aneurismas del tronco celíaco son un problema clínico infrecuente. La mayoría de los pacientes son sintomáticos al momento del diagnóstico; sin embargo, ocasionalmente se detectan de manera incidental durante estudios imagenológicos para otras enfermedades. Se presenta el caso de un paciente de 54 años con aneurisma sintomático del tronco celíaco, diagnosticado por tomografía e intervenido quirúrgicamente de manera satisfactoria.

Aneurysm of the celiac artery is an uncommon clinical problem; fewer than 180 cases have been reported in the world's medical literature. Most patients are symptomatic at the time of diagnosis. However, occasionally such aneurysms are detected incidentally during diagnostic imaging for other diseases. We present of a 54 years-old man who had a symptomatic celiac artery aneurysm detected by Computed tomography. The patient underwent successful resection of the aneurysm and revascularization of the celiac artery – common hepatic and splenic arteries with use of an PTFE graft.

Peculiaridades da circulação mesentérica em recém-nascidos e suas implicações em doenças gastrintestinais do período neonatal: [revisão] / Mesenteric circulation peculiarities in infant newborns and its implications in gastrointestinal illnesses of the neonatal period: [review]

OBJETIVO:Descrever peculiaridades da circulação mesentérica neonatal e caracterizar fatores de suscetibilidade ao desenvolvimento de doenças gastrintestinais e alterações do fluxo sanguíneo da artéria mesentérica superior por meio da dopplerfluxometria. FONTES DE DADOS: Livros-textos e publicações indexadas no Medline e SciELO nos últimos 20 anos, utilizando-se as palavras chaves: "mesenteric artery", "superior mesenteric artery", "newborn intestinal circulation", "necrotizing enterocolitis", "doppler flow velocimetry". SÍNTESE DOS DADOS: Alterações do fluxo sanguíneo mesentérico são um dos fatores predisponentes da enterocolite necrosante, doença neonatal de alta morbimortalidade que acomete principalmente prematuros. A circulação mesentérica é peculiar no período neonatal tanto em relação ao seu estado basal, quanto à sua resposta frente a estímulos fisiológicos. Variações da irrigação mesentérica podem ser inerentes à própria fase de desenvolvimento vascular intestinal do recém-nascido pré-termo, com possíveis agravos de fatores perinatais como: insuficiência placentária, asfixia, infecção, cateterismo umbilical, drogas (indometacina e cafeína), fototerapia, alimentação artificial e progressão rápida da dieta. A dopplerfluxometria permite o estudo da irrigação de órgãos-alvo e pode quantificar o fluxo sanguíneo, a resistência vascular e predizer situações de risco para doenças do trato gastrintestinal no período neonatal. CONCLUSÕES: O recém-nascido apresenta peculiaridades de irrigação sanguínea gastrintestinal. A dopplerfluxometria da artéria mesentérica superior é um método não invasivo que determina as condições circulatórias no território intestinal.

OBJECTIVE:To describe peculiarities of the neonatal mesenteric circulation and to characterize the susceptibility factors to the development of gastrointestinal illnesses and alterations of the superior mesenteric artery flow by the Doppler ultrasound method. DATA SOURCES: Textbooks and publications listed in Medline and SciELO from the last 20 years were searched using the key-words: "mesenteric artery", "intestinal superior mesenteric artery", "newborn circulation", "necrotizing enterocolitis", and "Doppler flow velocimetry". DATA SYNTHESIS: Alterations in the mesenteric flow are predisposing factors for necrotizing enterocolitis, which is a neonatal illness with high morbidity and mortality that occurs mainly in premature infants. The mesenteric circulation is peculiar at the neonatal period regarding its baseline status as well as its response from physiological stimulation. Mesenteric irrigation varies according to the proper phase of intestinal vascular development. Mesenteric irrigation can be damaged by perinatal factors, such as placental insufficiency, asphyxia, infection, umbilical catheters, drugs (indomethacin and caffeine), phototherapy, artificial feeding and fast diet progression. Doppler flow velocimetry allows the study of gut irrigations and may quantify blood flow and vascular resistance. The exam can predict risk situations for gastrointestinal illnesses during the neonatal period. CONCLUSIONS: The newborn infant presents peculiarities on gastrointestinal blood circulation. Superior mesenteric artery Doppler ultrasound provides non-invasive measures of the intestinal circulatory conditions.

Traslocación bacteriana: un problema para reflexionar

La traslocación bacteriana constituye el paso de las bacterias y sus productos a través de la mucosa gastrointestinal. Esto ayuda a explicar la aparente paradoja entre la no localización de un foco séptico y/o fallo multiorgánico. Se produce cuando quedan interrumpidos los mecanismos fisiológicos de protección contra la traslocación por disminución del flujo sanguíneo del mesenterio o por alteración de la estructura y funcionamiento del intestino por diversas causas, asociado con una alteración en la respuesta inmune del paciente. Actualmente se evalúa el grado de isquemia esplácnica a través del monitoreo por tonometría del pH gástrico que sirve de parámetro predictivo en la evaluación del paciente crítico.

Bacterial translocation is the passage of the bacterias and their products through the gastrointestinal mucosa. This helps to explain the evident paradox between non localizing a septic focus and/or a multiple organ failure. It occurs when the protective physiological mechanisms are interrupted against translocation by the decreased mesenteric blood flow, or by the alteration of the intestinal structure and function due to several causes, and associated with an alteration of the patient's immune response. At the present time, the grade of splanchnic ischemia is evaluated through the tonometrical monitoring of the gastric pH that acts as a predictive parameter in evaluating the critical patient.

Effects of nicardipine-induced hypotension on splanchnic perfusion in patient undergoing meningioma resection / 中华麻醉学杂志

Objective Controlled hypotension induced by different drugs may have different effects on splanchnic perfusion. The purpose of this study was to assess the effects of nicardipine- induced hypotension on splanchnic perfusion. Methods Twenty-three ASA Ⅰ-Ⅱ patients (14 male, 9 female) aged 21-60 yr undergoing meningioma resection were studied. The patients were premedicated with ranitidine 150 mg per os and atropine 0.5 mg i.m. Anesthesia was induced with propofol 1.5-2.0 mg?kg-1 , fentany1 2.0?g?kg-1 and vecuronium 0.1 mg? kg-1 and maintained with isoflurane inhalation and intermittent i. v. boluses of fentanyl and vecuronium. The patients were mechanically ventilated after tracheal intubation and PETCO2 was maintained at 33-35 mm Hg. Nicardipine-induced hypotension started from opening of mininges to the resection of tumor. 0.01% nicardipine infusion was started at 30 ml?h-1 and adjusted to reduce systolic blood pressure by 30% of the baseline or MAP to≥60 mm Hg. The adequacy of splanchnic perfusion was defined by gastric intramucosal CO2 tension (PgCO2), the intramucosal pH (pHi) and the difference between intramucosal and arterial PCO2(PCO2 gap) and was assessed before induction of anesthesia, the 1st, 2nd and 3rd hour during controlled hypotension and 1, 2 hour after termination of controlled hypotension. Results The MAP was maintained at about 62 mm Hg during controlled hypotension. The heart rate was stable. Hct was significantly decreased at 1st, 2nd and 3rd hour of hypotension compared with baseline but the mean Hct was greater than 30% . The intramucosal pH decreased slightly with no statistical significance and pHa, PaCO2 , PgCO2 and PCO2 gap were almost unchanged during controlled hypotension compared with the baseline values. Conclusion Nicardipine-induced hypotension is safe when MAP is maintained at≥60 mm Hg and has no adverse effects on splanchnic perfusion.