门脉性肺动脉高压

肺动脉高压的经典定义为平均肺动脉压（MPAP）升高，静息时〉25mmHg或运动时〉30mmHg。门脉性肺动脉高压（portopulmonary hypertension，PPHTN）是在门静脉高压基础上发生的，以肺动脉压（PAP）升高，肺血管阻力（PVR）增加而肺毛细血管楔压（PCWP）正常为特点的疾病.Mantz等于1951年首先描述了PPHTN，此后陆续有学报道了这种疾病。在1998年前，PPHTN与其它一些原因引起的肺动脉高压合称为继发性肺动脉高压，以此与原发性肺动脉高压相区别。根据WHO的最新分类，PPHTN不再归为继发性肺动脉高压的一种，而称为肝病或门静脉高压相关的肺动脉高压。     

Portopulmonary hypertension and liver transplantation: hemodynamic consequences at reperfusion

BACKGROUND: The absence of portopulmonary hypertension (PH) upon preoperative evaluation for liver transplantation (OLT) does not exclude the occasional occurrence of an acquired PH while awaiting a graft. We sought to estimate hemodynamic changes and right ventriculoarterial coupling during reperfusion. METHODS: We studied 11 cirrhotic patients diagnosed with mild PH, according to the current classification: mean pulmonary artery pressure (MPAP)-25 to 34 mm Hg. These patients underwent OLT, using the piggyback technique (group PH). None of them had exhibited criteria for PH on preoperative echocardiography. This cohort was compared with 20 consecutive cirrhotic patients with normal MPAP at OLT. We performed a complete hemodynamic profile using a pulmonary artery catheter (RVEF, Baxter-Edwards, Calif, USA) before and 5 minutes after reperfusion. The variables were MPAP and right ventricular (RV) end-diastolic volume index (RVEDVI). Using standard formulas we calculated RV stroke work index (RVSWI), RV end-systolic elastance (Ees), pulmonary effective elastance (Ea), and RV-arterial coupling efficiency as the Ees/Ea ratio. Systolic ventricular function was expressed as RVSWI versus RVEDVI. RESULTS: During the anhepatic phase, MPAP, Ees, Ea, and RVSWI were higher in the PH group; but RVEDVI was lower. After reperfusion the pressure (MPAP), contractility (RVSWI) and preload (RVEDVI) increased in both groups. However, afterload (Ea) decreased in the non-PH group; accordingly, Es/Ea increased only in these patients. DISCUSSION: At reperfusion, the expansion in preload and cardiac output, without a similar afterload decrease, is responsible for the steady increase in pressure. Our results have shown that in the PH patient group, systolic ventricular function improves during reperfusion by a Frank-Starling mechanism; however, ventricular-arterial uncoupling is maintained (Ees/Ea < 1) because ventricular contractility is not appropriately balanced by simultaneous declines in afterload.     

Cotransporters, WNKs and hypertension: an update

PURPOSE OF REVIEW: Studies of inherited conditions characterized by high or low blood pressure reveal the importance of a new signalling cascade, With no Lysine kinases (WNK) --> ste20/SPS1-related proline/alanine-rich kinase (SPAK)/oxidative stress-responsive kinase-1 (OSR1) --> Cation-Chloride Cotransporters (CCC), in regulating blood pressure and in the pathogenesis of essential hypertension. This review explores how these molecules interact to co-ordinate sodium homeostasis and how errors in these interactions may result in hypertension. RECENT FINDINGS: Studies using transgenic animals and gene knockins have clarified the role of mutant WNK4 in hypertension, by revealing its main action to be increasing the expression and activity of sodium-chloride cotransporter (NCC) in the kidney. Functional studies show how phosphorylation of WNK1 regulates both its activity and ability to interact with SPAK/OSR1, and clearly place it upstream of SPAK/OSR1 in the cascade. The structural basis for the interactions between SPAK/OSR1 and targets has been identified. SUMMARY: WNKs, activated by upstream kinases or autophosphorylation, bind and phosphorylate SPAK/OSR1, which in turn phosphorylate and activate NCCs and Na-K-Cl cotransporters (NKCCs). This increases sodium retention in the kidney (NKCC2, NCC) and vascular resistance (NKCC1), but decreases renin release (NKCC1). Hypertension-associated mutant WNKs increase surface expression and activation of renal tubular NKCC2 and NCC. Whether this adequately explains the hypertension awaits studies of these mutants in other tissues.     

Portopulmonary hypertension and the liver transplant candidate

The management of the liver transplant (OLT) candidate with portopulmonary hypertension (PPHTN) has dramatically changed in the past 3 years. Careful preoperative evaluation with functional characterization of right ventricular function plays a critical role. The pulmonary vascular response to epoprostenol infusion serves as a deciding factor for OLT candidacy. Careful perioperative attention to avoid right ventricular failure from acutely elevated pulmonary artery pressures or sudden increases in right ventricular preload is a key physiologic tenet of management. With increased surgical expertise, anesthetic sophistication, and availability of epoprostenol, PPHTN is no longer considered an absolute contraindication for OLT.     

Portopulmonary hypertension in the early phase following liver transplantation

BACKGROUND: Portopulmonary hypertension (PPH) is a severe complication of liver cirrhosis, which poses a high risk for postliver transplantation (LT) mortality. In most liver transplant centers, severe PPH is viewed as an absolute contraindication for LT, but recent reports challenge this. The purpose of our study was to determine the incidence of PPH, its influence on the 30-day mortality rate following LT and to determine the sensitivity and specificity of Doppler echocardiography and electrocardiography as noninvasive tools to determine PPH. METHODS: We studied 74 consecutive patients that underwent LT between February 2004 and November 2005. Pulmonary arterial pressure and cardiac index were repeatedly determined during surgery and postoperatively. PPH was defined as mild (mean pulmonary arterial pressure (MPAP) 25-35 mm Hg), moderate (MPAP of 35-45 mm Hg) and as severe (MPAP >45 mm Hg). RESULTS: The total incidence of PPH was 31% (16 mild, 5 moderate, and 2 severe). There was a tendency towards increased 30-day mortality rate in patients with PPH compared to controls (22% vs. 12%, P=0.1). However, the two patients with the most severe PPH survived. The duration of ventilation and total stay at the intensive care unit did not differ significantly between groups. The positive predictive value of Doppler echocardiography for PPH was 39% and the negative predictive value 90%. CONCLUSIONS: Mild pulmonary hypertension is common in patients with liver failure, whereas moderate and severe hypertension is not. Severe PPH should not be considered as absolute contraindication for LT.     

Portopulmonary shunt by splenopneumopexy for portal hypertension in children

Portopulmonary shunting by splenopneumopexy was successfully performed on seven children with portal hypertension, associated with extrahepatic portal vein occlusion in six and congenital hepatic fibrosis in one. Technically, this procedure is very simple and safely performed even in infancy. No operative mortality has been encountered to date. All children with portal hypertension treated by this portopulmonary shunt are doing very well, without any disturbances in their growth. Their postoperative survival ranges from 8 years and 9 months to 17 years and 9 months. Splenic pulp pressure was reduced to a postoperative mean value of 306 +/- 40.7 mmH2O from a preoperative mean value of 402.9 +/- 35.7 mmH2O. Hemorrhages esophageal varices were completely controlled postoperatively. Postoperative liver function tests were essentially unchanged from the preoperative values.     

Orthogenomics: an update

The study of genomics in orthopaedics has considerably lagged behind such study in other medical disciplines. Seminal work from other lines of medical research demonstrates the importance of genomic information in the evolution of personalized medicine. Common techniques for studying genome-phenotype associations include single nucleotide polymorphism, haplotype, and quantitative trait loci analysis. The few genome-based studies in major orthopaedic and related conditions have focused on osteoporosis, osteoarthritis, neuropathy and nerve compression, spinal deformity, trauma and inflammatory response, and pain and analgesia. The nascent field of orthogenomics, newly defined here as the application of genomic study to orthopaedic practice, has produced findings that could affect the practice of orthopaedics. However, more work is required, and the findings must be distilled and harnessed into applicable and achievable steps to improve clinical orthopaedic practice.     

Remifentanil: an update

PURPOSE OF REVIEW: Remifentanil has now reached maturity, as reflected by the increasing number of clinical papers relating to its use. Its position among anaesthetic drugs is now better understood, and this review will attempt to place it in the context of current clinical practice. RECENT FINDINGS AND SUMMARY: Propofol reduces the initial distribution of remifentanil, leading to higher concentrations during induction. Propofol and remifentanil administered together at sedative doses display a major synergistic interaction on the respiratory drive. Remifentanil accelerates the penetration of sevoflurane to its site of effect. The risk of intraoperative awareness seems to be low when remifentanil is associated to very low concentrations of hypnotic drugs, but this field warrants further investigation. Acute tolerance to opioids and its prevention remain controversial. SUMMARY: Remifentanil is the opioid of choice for tracheal intubation without muscle relaxants. It provides an alternative to regional anaesthesia in labour pain control. Target-controlled infusion may further improve the administration of remifentanil.     

Hypospadias： an update

Hypospadias is the most common congenital anomaly of the penis. The problem usually develops sporadically and without an obvious underlying cause. The ectopically positioned urethral meatus lies proximal to the normal site and on the ventral aspect of the penis, and in severe cases opens onto the scrotum or perineum. The foreskin on the ventral surface is deficient, while that on the dorsal surface is abundant, giving the appearance of a dorsal hood. Chordee is more common in severe cases. Cryptorchidism and inguinal hernia are the most common associated anomalies. The frequency of associated anomalies increases with the severity of hypospadias. For isolated anterior or middle hypospadias, laboratory studies are not usually necessary. Screening for urinary tract anomalies should be considered in patients with posterior hypospadias and in those with an anomaly of at least one additional organ system. The ideal age for surgical repair in a healthy child is between 6 and 12 months of age. Most cases can be repaired in a single operation and on an outpatient basis. Even patients with a less than perfect surgical result are usually able to enjoy a satisfactory sexual life.     

Mesangiolysis: an update

Mesangiolysis occurs in many renal diseases, both human and experimental. At least three types of mesangiolysis may be recognized, which differ in their mode of origin and in morphologic features. The first type is severe mesangiolysis with formation of glomerular cysts and subsequent cellular proliferation resembling glomerulonephritis. In the second type, mesangiolysis is associated with extensive widening of the subendothelial space and is thought to follow endothelial injury. The third type is mesangiolysis with lamellated mesangial nodules which is believed to result from relatively mild but persistent or recurrent localized mesangial, and perhaps also endothelial damage, with lysis of mesangial anchor points.     

Robotic surgery: an update

Minimally invasive surgery techniques have revolutionized surgery. Robotic surgery may be the next revolution in surgical technology. Robotics coupled with minimally invasive surgery and microscopic surgery provides the potential to do more complex and more precise tasks. Robotic surgery offers tremor filtration, motion scaling, indexed movements, additional degrees of freedom, and improved ergonomics. We explore robotic history, the present surgical technology, the current clinical cases and research, and the future of robotics. We will look specifically at the birth and progress of our own problem.     

Postburn scars: an update

Burn wounds give rise to the largest scars we can find in human pathology, influencing patients' quality of life. Despite the improved knowledge on pathophysiology, efficacy of the various treatments remains unsatisfactory. In this short review recent literature is examined with a focus on recent data on postburn pathological scars epidemiology and risk factors, which underline the high prevalence and the long evolution, pointing to identify this illness as a systemic inflammatory one, more frequent in women and in those of younger age, regulated by local factors relevant in wound healing.