Problems related to resuscitation in studies with contrast media]

This study has the purpose of describing indications and legal implications related to the intravascular use of contrast media (ICM) in order to provide useful guidelines to the intensivist, often involved in the treatment of adverse reactions. The structure of modern contrast media (CM), is a benzenic ring carrying steadily three iodine ions. Adverse reactions due to the use of ICM, are local or systemic ranging from skin rashes or flushes (urticaria et al.), to cardiovascular, respiratory and neurologic symptoms. The prevention of these reactions is mandatory in patients reporting a history of allergy or atopia disease. From a legal point of view, the contraindication to procedures involving i.v. use of CM are not clearly pointed out therefore several concerns have been expressed. The intensivist is not required to physically attend the procedure, in agreement with the circular #64 edited in 1979; on the other hand his prompt intervention should be granted if necessary. Furthermore every therapeutic supply suitable for any resuscitational intervention should be available in the area where the test is performed. In conclusion we would like to stress the financial and ethic implications related to the choice of ICM (ionic versus non-ionic). The use of non-ionic CM offers several advantages: among them the better tolerance for the patient and the lower incidence of adverse reactions. However non-ionic CM have a cost ten-fold higher and both groups of drugs have same incidence of fatal reactions, therefore the use of non-ionic ICM is recommended for high risk patients.     

Albumin and artificial colloids for massive bleeding

Rapid and massive bleeding has to be counteracted by efficient volume restoration against rapid loss of intravascular volume. There are two phases of volume management for massive bleeding, uncontrolled phase and controlled phase. During initial uncontrolled phase, rapid infusion of crystalloid with RCC (red cell concentrate) is the first choice of volume management to prevent shock and profound decline of hemoglobin level. After shifting to the next controlled phase, artificial colloids and RCC become the next choice for efficient volume restoration. Although albumin has not been proven to improve prognosis in clinical studies, anti-inflammatory effect could be expected. Albumin infusion may be followed in this phase, and also albumin concentrate may be beneficial to reduce subsequent tissue edema due to massive infusion of crystalloid and artificial colloid. A new generation of hydroxyethyl starch is a promising blood substitute, designed with minimum side effect. Although renal damage especially in septic patient and coagulation disorder are theoretically suspected, beneficial effect as volume expansion overwhelms these stochastic side effects. Since the side effect depends on the dose and how much it remains in the body, a purposeful use during volume expansion phase should be recommended.     

Mid-term results of overlapping cardiac volume reduction for ischemic cardiomyopathy

BACKGROUND: Left ventricular restoration (LVR) is thought to be effective for ischemic cardiomyopathy (ICM). We assessed the early and mid-term results of overlapping cardiac volume reduction (OLCVR) as an operation for LVR on patients with ICM. METHODS: From February to June 2004, 4 patients with ICM underwent OLCVR in our department. RESULTS: There was no death. Significant decreases in the left ventricular end diastolic volume index and in the left ventricular end systolic volume index were observed in the early postoperative period in all the 4 patients. These effects were still evident 1 year later, with improved New York Heart Association (NYHA) functional class and a smaller left ventricular diastolic diameter. One patient required implantation of a cardioverter defibrillator 16 months postoperatively. CONCLUSION: The favorable early and mid-term results of the OLCVR indicate that it is an effective procedure for patients with ICM.     

Perioperative colloid administration: a survey of Spanish anesthesiologists' attitudes

OBJECTIVES: To determine the availability of intravascular fluid volume replacement solutions in Spanish hospitals, to survey the extent of use of colloids by anesthesiologists, to ascertain the possible adverse effects they seek to prevent when using each solution, and to assess their level of knowledge about the subject. MATERIAL AND METHODS: A questionnaire was administered over a period of 6 months (July 2004-January 2005). The questionnaire was available online at www.encuestacoloides.com. The address was distributed by e-mail to anesthesiologists of all the Spanish autonomous communities and published in the Revista Espa?ola de Anestesiología y Reanimación. RESULTS: One hundred forty-two anesthesiologists responded. Crystalloids and colloids were widely available in most hospitals. Hydroxyethyl starch (HES) solutions were the colloids most often used (73%), followed by gelatins (28%). Dextran solutions, on the other hand, were no longer being used. The reasons the respondents gave for using these solutions were related to the time they remained in the vascular system, their greater effect of volume expansion, and the preservation of hemostasis. The most-feared complication was anaphylactic reaction to gelatins and there were concerns about the dose limit for infusion of HES solutions and about hemodynamic instability caused by dextran solutions. Fifty-four percent felt that scientific meetings provide little information about colloids and volume replacement. CONCLUSIONS: There is widespread use of colloids other than dextran along with crystalloids for plasma volume replacement. Spanish anesthesiologists are clear about important concepts related to colloid use. However, a high percentage have doubts about certain fundamental issues. Continuing professional development opportunities related to intravascular fluid replacement therapy should be increased.     

A surgeon''s guide to herbal supplements

The use of herbal supplements has steadily increased in the United States over the last decade. Despite the increased awareness of alternative therapies by the government and lay public, many physicians do not ask their patients about their use of these alternative medications. In addition, many physicians are unaware of the possible side effects that may occur when a patient consumes these substances. Considering a number of these supplements have been associated with adverse reactions in the perioperative period, it is important for a surgeon to understand all of the herbs a patient may be taking. The purpose of this article is to discuss the growing trend of herbal use among surgical patients and give the reader some background on the most commonly used herbs.     

Effect of intravascular volume expansion on renal function during prolonged CO2 pneumoperitoneum

OBJECTIVE: To evaluate whether intravascular volume expansion would improve renal blood flow and function during prolonged CO2 pneumoperitoneum. SUMMARY BACKGROUND DATA: Although laparoscopic living donor nephrectomies have a considerably reduced risk of complications for the donors, significant concerns exist regarding procurement of a kidney in the altered physiologic environment of CO2 pneumoperitoneum. Recent studies have documented adverse effects of CO2 pneumoperitoneum on renal hemodynamics. METHODS: Renal and systemic hemodynamics and renal histology were studied in a porcine CO2 pneumoperitoneum model. After placement of a pulmonary artery catheter, carotid arterial line, Foley catheter, and renal artery ultrasonic flow probe, CO2 pneumoperitoneum (15 mmHg) was maintained for 4 hours. Pigs were randomized into three intravascular fluid protocol groups: euvolemic (3 mLkg/hour isotonic crystalloid), hypervolemic (15 mL/kg/hour isotonic crystalloid), or hypertonic (3 mL/kg/hour isotonic crystalloid plus 1.2 mL/kg/hour 7.5% NaCl). RESULTS: In the euvolemic group, prolonged CO2 pneumoperitoneum caused decreased renal blood flow, oliguria, and impaired creatinine clearance. Both isotonic and hypertonic volume expansions reversed the changes in renal blood flow and urine output, but impaired creatinine clearance persisted. CONCLUSIONS: Intravascular volume expansion alleviates the effects of CO2 pneumoperitoneum on renal hemodynamics in a porcine model. Hypertonic saline (7.5% NaCl) solution may maximize renal blood flow in prolonged pneumoperitoneum, but it does not completely prevent renal dysfunction in this setting. This study suggests that routine intraoperative volume expansion is important during laparoscopic live donor nephrectomy.     

The influence of tidal volume on the dynamic variables of fluid responsiveness in critically ill patients

Respiratory-related variabilities in stroke volume and arterial pulse pressure (Delta%Pp) are proposed to predict fluid responsiveness. We investigated the influence of tidal volume (Vt) and adrenergic tone on these variables in mechanically ventilated patients. Cyclic changes in aortic velocity-time integrals (Delta%VTI(Ao), echocardiography) and Delta%Pp (catheter) were measured simultaneously before and after intravascular volume expansion, and Vt was randomly varied below and above its basal value. Intravascular volume expansion was performed by hydroxyethyl starch (100 mL, 60 s). Receiver operating characteristic curves were generated for Delta%VTI(Ao), Delta%Pp and left ventricle cross-sectional end-diastolic area (echocardiography), considering the change in stroke volume after intravascular volume expansion (> or =15%) as the response criterion. Covariance analysis was used to test the influence of Vt on Delta%VTI(Ao) and Delta%Pp. Twenty-one patients were prospectively included; 9 patients (43%) were responders to intravascular volume expansion. Delta%VTI(Ao) and Delta%Pp were higher in responders compared with nonresponders. Predictive values of Delta%VTI(Ao) and Delta%Pp were similar (threshold: 20.4% and 10.0%, respectively) and higher than that of left ventricle cross-sectional end-diastolic area at the appropriate level of Vt. Delta%Pp was slightly correlated with norepinephrine dosage. Delta%Pp increased with the increase in the level of Vt both before and after intravascular volume expansion, contrasting with an unexpected stability of Delta%VTI(Ao). In conclusion, Delta%VTI(Ao) and Delta%Pp are good predictors of intravascular fluid responsiveness but the divergent evolution of these two variables when Vt was increased needs further explanation.     

Colloid solutions: a clinical update

Albumin, dextran, gelatin, and hydroxyethyl starch (HES) solutions are colloids that efficiently expand the circulating blood volume. The administration of colloids restores the intravascular volume with minimal risk of tissue edema in comparison with crystalloid solutions alone. However, colloids are always given for surgical and critically ill patients. The type of the colloid, volumes applied, aggressiveness of fluid resuscitation, and the volume status at the initial phase of administration determine their clinical responses. The outcome after fluid resuscitation with various colloids in critically ill patients seems to be comparable according to systematic reviews. A randomized, adequately powered clinical trial comparing modern nonprotein colloid to albumin is still lacking. Rapidly degradable HES solutions have good hemodynamic effects, and the risk of adverse renal and coagulation effects, as well as allergic reactions, is minimal. The current investigation has also shown the beneficial effect of HES solution (especially HES 130/0.4) on inflammatory response, postoperative nausea and vomiting, and postoperative outcome. The indication of colloids with an assessment of the degree of hypovolemia and safety profiles should thus be taken into consideration before colloid administration.     

The Effects of the Iodinated X-Ray Contrast Media Iodixanol,Iohexol, Iopromide,and Ioversol on the Rat Kidney Epithelial Cell Line NRK 52-E

Nephrotoxicity, associated with the administration of iodinated X-ray contrast media (ICM), continues to be a major side effect in a significant number of vulnerable patients undergoing diagnostic X-ray imaging procedures. The molecular mechanisms underlying these adverse effects on the kidneys are unclear despite several decades of investigation. Side effects are more common after exposure to high-osmolar compared with low-osmolar ICM, suggesting that osmolality may be an important physical–chemical property related to nephrotoxicity. This investigation in cultured NRK 52-E cells, a cell line of renal origin, compares the in vitro toxicity of the iso-osmolal ICM iodixanol with the low-osmolal ICM iohexol, iopromide, and ioversol. The cellular toxicity was evaluated with the trypan blue exclusion assay, the MTT assay, and incidences of cell death. A qualitative assessment of vacuolation of the cultured NRK 52-E cells was taken as a measure of intracellular uptake of ICM. A difference in cell death incidence was observed between the iso-osmolal iodixanol and the low-osmolal iohexol, iopromide, and ioversol contrast media, with the iso-osmolal iodixanol having the least effect in each of the in vitro systems tested. The osmolality of the contrast media appeared to be the major cause for the observed in vitro toxicity.     

The effects of the iodinated X-ray contrast media iodixanol, iohexol, iopromide, and ioversol on the rat kidney epithelial cell line NRK 52-E

Nephrotoxicity, associated with the administration of iodinated X-ray contrast media (ICM), continues to be a major side effect in a significant number of vulnerable patients undergoing diagnostic X-ray imaging procedures. The molecular mechanisms underlying these adverse effects on the kidneys are unclear despite several decades of investigation. Side effects are more common after exposure to high-osmolar compared with low-osmolar ICM, suggesting that osmolality may be an important physical-chemical property related to nephrotoxicity. This investigation in cultured NRK 52-E cells, a cell line of renal origin, compares the in vitro toxicity of the iso-osmolal ICM iodixanol with the low-osmolal ICM iohexol, iopromide, and ioversol. The cellular toxicity was evaluated with the trypan blue exclusion assay, the MTT assay, and incidences of cell death. A qualitative assessment of vacuolation of the cultured NRK 52-E cells was taken as a measure of intracellular uptake of ICM. A difference in cell death incidence was observed between the iso-osmolal iodixanol and the low-osmolal iohexol, iopromide, and ioversol contrast media, with the iso-osmolal iodixanol having the least effect in each of the in vitro systems tested. The osmolality of the contrast media appeared to be the major cause for the observed in vitro toxicity.     

新鲜冰冻血浆在危重症患者中应用的进展

伴随着大力倡导成分输血,新鲜冰冻血浆（FFP）的需求日益增多。FFP是补充血容量、纠正患者凝血状态、改善血管内皮的重要物质,在危重症患者中的应用尤为广泛。大约50%左右的FFP在凝血障碍的危重症患者中预防性使用。在有创操作前预防性使用FFP的作用有限,不仅没有降低患者术后出血的风险,而且增加了术后急性肺损伤的发生。对于脓毒症、失血性休克等危重症患者,尽早应用FFP进行液体复苏,能显著改善患者的预后,降低患者的死亡率。全文拟从FFP在危重症患者中的应用、目前临床应用存在的问题,以及可能引起的不良反应等内容作一总结,以期为临床中FFP的合理使用提供参考。     

Comparison of Iodixanol and Iohexol in Patients Undergoing Intravenous Pyelography: A Prospective Controlled Study

Background. Nephropathy associated with contrast medium exposure is a well-known complication of IVP. However, it is uncertain whether iso-osmolar non-iodinated contrast medium (iodixanol) is less nephrotoxic than low-osmolar contrast medium (iohexol). Materials and Methods. In this single-center, double-blind, prospective study, 50 patients undergoing IVP were randomized into two groups receiving different contrast medium: iodixanol and iohexol. Patients in high risk for contrast nephropathy were included, 28 with renal insufficiency and 19 with diabetes mellitus. We compared the nephrotoxic effect (contrast nephropathy), complement and cytokines profile between the iodixanol and iohexol groups. The mean volume of contrast medium in each IVP procedure was 0.8 mL/kg. Results. The incidence of contrast nephropathy was 4 percent among all patients (one iodixanol and one iohexol). We found no significant differences in contrast nephropathy and allergic reactions between the two groups. There was no significant difference in cytokine profiles in both groups (p > 0.05).The incidence of allergic reaction was 16 percent among all patients. Twelve percent (3/25) had late reaction after iohexol exposure compared to four percent (2/25) with iodixanol (p = 1.0). One patient had severe skin rash due to late adverse reaction after iodixanol. No mortality was found. Conclusions. New iodixanol and iohexol contrast medium for routine IVP examination are safe and have low nephrotoxicity profile, especially in elderly or high-risk patients. Iodixanol contrast medium has an increased risk to induce severe late adverse reaction compared to iohexol. Allergic reaction may be the main adverse effect after contrast medium infusion.     

Lumbar myelography with amipaque.

In lumbar myelography, early side effects occur in about half the patients examined with modern water-soluble contrast media. At myelography with Amipaque (metrizamide) these reactions are usually minor, and serious adverse reactions are rare. In our own series of 650 consecutive lumbar myelographies with Amipaque there were no serious adverse effects. Minor adverse reactions occurred in 56% of the patients. Transient electroencephalogram (eeg) changes were seen in 14% of the patients, with only 5 patients showing paroxysmal spike activity. Adhesive arachnoiditis following lumbar myelography occurs significantly less often with Amipaque than with any other contrast medium. The properties of Amipaque provide excellent possibilities for detailed studies of all parts of the spinal subarachnoid space, and the medium constitutes a new and interesting aid for these investigations.     

Acute intravascular volume expansion with rapidly administered crystalloid or colloid in the setting of moderate hypovolemia

Although the distribution of various crystalloid and colloid solutions at equilibrium has been well established, the acute peak expansion of intravascular volume that can be achieved with the rapid administration of crystalloid or colloid is unknown. We studied eight healthy male subjects in a two-part crossover trial designed to assess the maximal increase in intravascular volume achieved with 1000 mL of lactated Ringer's solution compared with the same volume of 6% Hetastarch. Subjects were made moderately hypovolemic by the withdrawal of 900 mL of blood, and then the crystalloid or colloid solution was rapidly infused over 5-7 min. Serial dilution of hematocrit was measured every 5 min for 30 min to determine changes in blood volume. Peak expansion of intravascular volume with lactated Ringer's solution was 630 +/- 127 mL, occurring immediately the rapid infusion was complete, whereas the peak expansion of intravascular volume with 6% Hetastarch was 1123 +/- 116 mL and occurred 5 min after the completion of the fluid infusion. The results were significantly different (P < 0.001). These results would suggest that even for very short periods of time, rapid infusion of colloid significantly more effectively increases blood volume and, by inference, cardiac output than the same volume of crystalloid, even if the crystalloid is administered very rapidly. IMPLICATIONS: Under conditions of moderate hypovolemia, the maximal acute intravascular volume expansion with the rapid infusion of 1000 mL of lactated Ringer's solution is slightly more than half that achieved with the same volume of 6% Hetastarch.     

Iopamidol in lumbar myelography

Iopamidol is a new, nonionic, water-soluble contrast material currently undergoing clinical trials for intravascular and intrathecal use in Europe and the United States. In this study, 12 patients underwent lumbar myelography with this agent. For each subject, up to 12 mL of iopamidol (at 200 mg I/mL) was employed. The myelograms obtained were highly satisfactory. No serious adverse reactions were observed. The most common side effect-headache-occurred in seven patients. However, six of the seven headaches were mild and transient, and did not require treatment. Nausea occurred in two patients, back pain in two patients, hypotension and hypertension each in one patient. All of these reactions were mild and self-limited. Iopamidol appears to be a safe and conveniently used agent for lumbar myelography.     

Effects of intravascular volume expansion on cerebral blood flow in patients with ruptured cerebral aneurysms

To clarify the effect of intravascular volume expansion on cerebral blood flow (CBF) in patients after subarachnoid hemorrhage (SAH), we performed 55 pairs of regional CBF measurements using the xenon-133 inhalation method before and after volume expansion in 35 patients with ruptured cerebral aneurysms. CBF was calculated as the hemispheric mean value of the initial slope index. To accomplish volume expansion, we transfused 500 ml of 5% human serum albumin in half an hour. After volume expansion with albumin, the hemoglobin value decreased significantly (P less than 0.005). Volume expansion did not change the mean arterial blood pressure. During the first 2 weeks after SAH, CBF decreased significantly after volume expansion (P less than 0.005). During the 3rd week after SAH and subsequently to the 4th week after SAH, volume expansion produced no change in CBF. In patients with symptomatic vasospasm, CBF decreased significantly after volume expansion (P less than 0.005). In patients without symptomatic vasospasm, volume expansion produced no change in CBF. The results of this study suggest that increasing the intravascular volume above normal by volume expansion does not increase CBF or reverse symptomatic vasospasm.     

Modification of focal cerebral ischemia by cardiac output augmentation

Intravascular volume expansion has been employed successfully for treatment of ischemic stroke from cerebral vasospasm and from cerebrovascular occlusive disease. The physiologic mechanism responsible for this success has not previously been delineated in controlled experimentation. The objective of this investigation was to delineate the effects of cardiac output and of hemodilution in a primate model of focal cerebral ischemia. Two groups of anesthetized rhesus monkeys received extensive cardiovascular monitoring, and local cerebral blood flow (lCBF) was determined in both ischemic and nonischemic brain regions by the hydrogen clearance method. Both groups were subjected to unilateral middle cerebral artery occlusion. One group then underwent blood volume expansion with Dextran 40 (cardiac output augmentation), and one group underwent isovolemic hemodilution with Dextran 40, cardiac output being maintained constant. Significant increases in lCBF occurred in ischemic regions only and occurred only in response to augmentation of cardiac output. Isovolemic hemodilution failed to produce any changes in lCBF. This investigation indicates that ischemic brain regions are selectively vulnerable to alterations in cardiac output, these effects being independent of alterations in blood pressure. Blood viscosity changes may play only a minor role. This study strongly suggests an important role of intravascular volume expansion and cardiac output augmentation in treatment of acute ischemic stroke.     

Decongestive Treatment of Acute Decompensated Heart Failure: Cardiorenal Implications of Ultrafiltration and Diuretics

In patients with acute decompensated heart failure (ADHF), treatment aimed at adequate decongestion of the volume overloaded state is essential. Despite diuretic therapy, many patients remain volume overloaded and symptomatic. In addition, adverse effects related to diuretic treatment are common, including worsening kidney function and electrolyte disturbances. The development of decreased kidney function during treatment affects the response to diuretic therapy and is associated with important clinical outcomes, including mortality. The occurrence of diuretic resistance and the morbidity and mortality associated with diuretic therapy has stimulated interest to develop effective and safe treatment strategies that maximize decongestion and minimize decreased kidney function. During the last few decades, extracorporeal ultrafiltration has been used to remove fluid from diuretic-refractory hypervolemic patients. Recent clinical studies using user-friendly machines have suggested that ultrafiltration may be highly effective for decongesting patients with ADHF. Many questions remain regarding the comparative impact of diuretics and ultrafiltration on important clinical outcomes and adverse effects, including decreased kidney function. This article serves as a summary of key clinical studies addressing these points. The overall goal is to assist practicing clinicians who are contemplating the use of ultrafiltration for a patient with ADHF.     

Benefits and risks of nonsteroidal antiinflammatory drugs in steroid-resistant nephrotic syndrome

In this paper we discuss the effects of nonsteroidal antiinflammatory drugs on proteinuria and the specific risks of these drugs in patients with nephrotic syndrome. We summarize the results of a prospective uncontrolled trial of meclofenamate in severe steroid-resistant nephrotic syndrome secondary to focal glomerular sclerosis and idiopathic membranous nephropathy. This study examined the effect of meclofenamate on proteinuria, serum albumin levels, serum cholesterol, serum triglycerides, renal function, BP, liver function tests, and hematologic values. We also sought and evaluated adverse reactions due to this medication. We offer some suggestions for selective use and careful supervision of NSAIDs in the nephrotic syndrome.     

慢性尿酸性肾病致肾功能损害患者的临床诊治研究

目的：探讨慢性尿酸性肾病致肾功能损害患者的临床诊治方法。方法选取本院2011年10月～2013年10月诊治的慢性尿酸性肾病致肾功能损害患者83例,根据治疗方案分为两组,41例患者实施常规治疗为对照组,42例患者加用别嘌呤醇为观察组,疗程8周,比较两组患者相关临床指标的改变情况、临床疗效、不良反应情况。结果治疗后,对照组患者血尿酸显著下降,而尿pH值显著升高。观察组患者血尿酸、血肌酐、尿素氮、24h尿蛋白均显著下降,而肾小球滤过率、尿pH值均显著升高。观察组患者血尿酸、血肌酐、尿素氮、24h尿蛋白均明显低于对照组,观察组患者肾小球滤过率、总有效率均明显高于对照组,差异均有统计学意义（P＜0.05）。结论别嘌呤醇是治疗慢性尿酸性肾病致肾功能损害的有效药物,可明显改善患者的临床指标,提高治愈率,引发的不良反应少,具有较高的安全性,值得临床推广使用。