Comparison of oblique versus hockey-stick surgical incision for kidney transplantation.

The hockey-stick surgical incision is becoming more popular than the oblique incision for kidney transplantations. Both incisions are convenient and comfortable. Both have some drawbacks, such as muscle denervation for the former, or section of lateral muscles for the latter. In this retrospective study, we compared these incisions with regard to the incidence of long-term complications, such as postincisional hernia, relaxation of the abdominal wall, and a poor cosmetic result. One hundred patients (50 of each type) were evaluated at an average of 4.5 years after transplantation (3 months-15 years). Occurrence of incisional hernia was 16% in the former (8 cases) versus 4% in the latter (2 cases: X(2) = 4; P < .05). A major relaxation of the abdominal wall was found in 24% of the former (12 cases) versus 8% of the latter (4 cases) (X(2) = 4.76; P < .05). These complications were not correlated with age, sex, weight, side of transplant, or immunosuppressive drugs. In the former patients with hockey-stick incisions, the overall cosmetic results were poor, because in most cases the incision had been prolonged upward, above the transverse umbilical line, even as high as the costal arch. In 20% of the former patients with hockey-stick incisions, the scar had widened, particularly in the upper vertical branch of the J incision. We conclude that the final outcome of the oblique surgical incision was better than the hockey-stick incision because of the lower incidence of hernia and abdominal wall relaxation and the more favorable cosmetic results.

The relationship between plasma taurine and other amino acid levels in human sepsis.

Although reports of decreased plasma taurine in trauma, sepsis and critical illness are available, very little is known about the relationships among changes in plasma taurine, other amino acid levels and metabolic variables. We analyzed a large series of plasma amino acid profiles obtained in trauma patients with sepsis who were undergoing total parenteral nutrition. The correlations between plasma taurine, other amino acid levels, parenteral substrate doses and metabolic and cardiorespiratory variables were assessed by regression analysis. Post-traumatic hypotaurinemia was followed by partial recovery toward less abnormal values when sepsis developed. Levels of taurine were directly and significantly related to levels of glutamate, aspartate, beta-alanine and phosphoethanolamine (and unrelated to other amino acids). Levels of these amino acids increased simultaneously with increasing doses of leucine, isoleucine and valine in total parenteral nutrition. Decreasing taurine was associated with increasing lactate, arteriovenous O(2) concentration difference and respiratory index, and with decreasing cholesterol and cardiac index. These results characterize the relationships between plasma taurine and other amino acid levels in sepsis, provide evidence of amino acid interactions that may support taurine availability and show more severe decreases in plasma taurine with the worsening of metabolic and cardiorespiratory patterns.

Taurine and pulmonary hemodynamics in sepsis.

This study has been performed to characterize the relationship between changes in plasma taurine (TAU) and hemodynamic patterns in sepsis. Analysis of 249 plasma aminoacidograms (AA-grams) and associated measurements in a group of critically ill, mechanically ventilated septic patients, showed that decreases in TAU were significantly correlated with increases in pulmonary artery pressure and pulmonary vascular resistance, and with worsening of pulmonary dysfunction. All cases requiring positive end-expiratory pressure greater than 10cmH2O had TAU lower than 50 microM/L. Low TAU was paralleled by decreases in other sulfur-containing AA, phosphoethanolamine, beta-alanine, glutamate and aspartate, within a pattern of greater metabolic dysregulation. These data provide evidence of a link between severity of pulmonary dysfunction and reduced TAU availability in clinical sepsis. The implications relate also to the need for specific investigations of the clinical effect of exogenous TAU on proinflammatory mediator-induced pulmonary dysfunction.

Pathophysiologic correlates of hypocholesterolemia in critically ill surgical patients.

OBJECTIVE: To assess correlates of hypocholesterolemia in moderate to critical surgical illness. DESIGN: Prospective analysis of laboratory and clinical data. SETTING: Department of surgery in a university hospital. PATIENTS: 135 patients undergoing uncomplicated abdominal surgery or with sepsis, liver failure, hemorrhage, severe cholestasis, or multiple organ dysfunction syndrome (MODS). INTERVENTIONS: Surgical and/or medical therapy according to clinical status. MEASUREMENTS AND MAIN RESULTS: Determinations of total cholesterol, additional variables, and clinical data. Cholesterol decreased after surgery, in sepsis, liver failure, acute hemorrhage, and MODS and increased in cholestasis. Hypocholesterolemia correlated with decreases in plasma proteins and indices of hepatic protein synthetic adequacy, with hemodilution from blood loss, and was moderated or prevented by cholestasis. CONCLUSIONS: These results help to explain the dynamics of the development, clinical relevance, and negative prognostic value of hypocholesterolemia in critical illness.

Quantitative assessment of changes in blood CO(2) tension mediated by the haldane effect.

Adequate assessment of circulatory and gas-exchange interactions may involve the quantification of the Haldane effect (HE) and of the changes in blood PCO(2) mediated by changes in Hb-O(2) saturation and O(2)-linked CO(2) binding. This is commonly prevented by the complexity of the involved calculations. To simplify the task, a large series of patient measurements has been processed by regression analysis, thus developing an accurate fit for this quantification (v-a) PCO(2)HE + 0.460 [(a-v) HbO(2)]0.999e0.015(PvCO(2))-0.852(Hct) (n = 247, r(2) = 0. 99, P << 0.001), where (v-a)PCO(2 HE) is the reduction in venous PCO(2) (Pv(CO(2)), Torr) allowed by the chemical binding of CO(2) in blood due to the HE (Torr), (a-v)HbO(2) is the arteriovenous difference in Hb-bound O(2) (ml/dl), and Hct is hematocrit fraction. Values of (v-a)PCO(2 HE) estimated by this expression compared well with the results of previously published experiments. This formula is useful in assessing the impact of HE on Pv(CO(2)) and venoarterial PCO(2) gradient and the survival advantage offered by HE in extreme conditions. Use may be extended to all investigative and clinical settings in which changes in blood O(2) saturation and O(2)-linked CO(2) binding must be converted into the corresponding changes in dissolved CO(2) and PCO(2).

[Hepatic angioma: rational simplification of diagnostic procedures]. / Angioma epatico: semplificazione razionale del procedimento diagnostico.

The contribution of various techniques to the diagnosis of hepatic angioma has been evaluated retrospectively in 32 patients. The features characterizing hepatic angioma in each technique (ultrasound, Doppler-ultrasound, computed tomography, angiography, scintigraphy, nuclear magnetic resonance) have also been evaluated. The results support the primary role of ultrasound for detecting hepatic lesions and for monitoring their evolution, because of the high sensitivity and of the easy availability of the technique. Doubts on the nature of the lesions should be resolved by using techniques with a higher specificity: scintigraphy for lesions larger than 3 cm in diameter, and computed tomography or nuclear magnetic resonance for lesions of even smaller sizes.

Computer-assisted analysis of the impact of respiratory quotient on blood CO2 tension and pH changes.

A computer model for the accurate quantification of blood gas exchange components was used to assess the impact of respiratory quotient (RQ) on venoarterial CO2 tension and pH differences over a large group of patient measurements. The combined use of measured and computer-generated data has shown that, for any given increase in blood CO2 concentration (i.e., when the arterial blood becomes venous), the associated increase in CO2 tension and decrease in pH are inversely related to the RQ, and that this relationship is mediated by the Haldane effect. These results are useful for a through understanding of blood gas and metabolic interactions in normal and abnormal states, and for improving the interpretation of changes in venoarterial CO2 tension gradient in clinical monitoring.

The relationship between oxygen extraction and venous pH in sepsis.

This study was performed to quantify the impact of Haldane effect (HE) on the relationship between O2 extraction (O2Ex; mL O2/dL blood) and venous pH in 247 measurements performed in 91 septic patients (73 patients with intra-abdominal sepsis, 11 with retroperitoneal abscesses, 6 with severe cholangitis, and 1 with gangrenous fasclitis). The severity of sepsis varied from relatively compensated to extremely diseased conditions. This allowed a detailed assessment of the impact of HE over a wide range of cardiorespiratory and metabolic abnormalities. A recently developed model was used to quantify blood CO2 exchange and Haldane relationships and, in particular, the buffering of venous pH allowed by O2Ex (O2-linked H+ binding) on the basis of arterial and mixed venous blood gas measurements. Arterio-venous pH difference (a-vDpH) was .033 +/- .024 (mean +/- SD). It increased with venoarterial CO2 concentration difference (v-aDCO2; mL CO2/dL blood), but the increase was moderated by a simultaneous increase in O2Ex, as the likely consequence of HE: a-vDpH = .006 + .017 (v-aDCO2) - .009 (O2Ex) [r2 = .96, p < < .001]. To confirm this, the moderation of a-vDpH allowed by the HE (DpH) was calculated. A first component, due to O2-linked H+ binding, had a value of .016 +/- .012, and a second component, due to the Haldane-mediated reduction in venous CO2 tension and plasma carbonic acid concentration, had a value of .019 +/- .006. Their sum (total DpH) was .033 +/- .017 and was related directly and strongly to O2Ex: DpH = -.002 + .009 (O2Ex) [r2 = .85, p < < .001], thus confirming the quantitative impact of HE in moderating the decrease in venous pH relative to arterial pH. The loss of this effect was responsible for the larger decreases in venous pH observed in hypodynamic patients developing impaired O2Ex. These results allow an easy quantification of the Haldane component, separated from the other components affecting pH, and are also useful for assessing the protective role exerted by HE against excessive decreases in venous pH in circulatory failure.

[The branched-chain amino acids]. / Gli aminoacidi ramificati.

Branched-chain amino acids (BCAA: leucine, isoleucine and valine) are not just structural constituents of proteins, but have ''pharmacologic'' properties, known for several years: BCAA are catabolized mainly in muscle; can be oxidized with energy production, being nitrogen donors for other amino acids; regulate protein synthesis and degradation; modulate metabolism of neuroactive mediators. These properties make the clinical use of BCAA particularly suitable in critical conditions such as liver cirrhosis, sepsis, surgical or nonsurgical trauma, acute renal failure, acute pancreatitis, cancer, in which energy production from conventional substrates is altered and, at the same time, reduction of protein catabolism and enhancement of synthetic processes is advisable. Recently, the changes of plasma aminoacidograms induced by the administration of high-dose BCAA in sepsis have been better detailed: 1) a tendency to normalization of high levels of proline and of other amino acids transported intracellularly by transport system ''A''; 2) less relevant reduction of the levels of other amino acids; 3) increase of the levels of taurine, glutamate and aspartate; more complex interactions with specific amino acids. These changes, and changes of other variables, reconfirm in part some well-known properties of BCAA, and are also objective indicators of an improvement of the metabolic abnormalities of sepsis induced by BCAA administration. In sepsis and in other stress conditions it is recommended to administer, within balanced parenteral nutritional regimens, AA solutions with a 35-50% BCAA concentration.

[Medium-chain triglycerides in artificial nutrition]. / I trigliceridi a catena media (MCT) in nutrizione artificiale.

Medium Chain Triglycerides (MCT) are lipids which are commonly present in nature, for instance in milk and in some vegetable oils. The MCT molecule is composed of glycerol esterified with saturated linear-chain fatty acids containing 6 to 12 carbon atoms (MCFA: Medium Chain Fatty Acids: C(6:0), esanoic acid; C(8:0), octanoic acid; C(10:0), decanoic acid; C(12:0), dodecanoic acid). MCT for clinical use are currently obtained from vegetable fat through industrial processing. The large interest for MCT in clinical nutrition is due to unique physico-chemical, biochemical and metabolic features, which characterize MCT compared to conventional lipids (LCT: Long Chain Triglycerides). In particular, MCT represent a source of rapidly, fully available and ''high density'' energy, which makes their use very advantageous and suitable in a wide range of clinical situations, from the premature newborn to the adult patient. In addition to the MCT oil, known to physicians and nutritionists since the 1950s, and to the many commercially available MCT-containing compounds for oral-enteral use, in the last years it has become possible also to administer MCT-containing emulsions in parenteral nutrition. This has allowed to improve further knowledge of the effects of MCT, expanding the indications for use, often as a ''first-choice'' substrate in different types of critically ill patients.

Retroperitoneal cystic lymphangioma.

Two cases of retroperitoneal cystic lymphangioma (CL) are presented; the current literature on this rare, benign neoplasm of the lymphatic system is reviewed. This tumor consists of various numbers of cyst-like cavities filled with a serous, serosanguineous or chylous fluid. The histogenesis of CL is still uncertain. Most commonly CL occurs in the neck and in the axillary region, whereas it is rare in the retroperitoneum. Although retroperitoneal CL is a benign lesion, it may cause significant morbidity due to its large size, and its often invasive character with a strong tendency to secondary infection. The treatment of choice is surgical excision.

[The surgical risk of liver resections for neoplasms in the elderly patient]. / Il rischio operatorio delle resezioni epatiche per neoplasia nel paziente anziano.

For patients who are candidates for surgical resection of the liver, advanced age has, for many years, been considered to be a limiting factor or has precluded intervention. More recently, improvements in diagnostic, surgical and anaesthetic techniques and the increase in the average age of the population have gradually broadened the indications for hepatic resection in elderly patients. The factors for reappraisal of the surgical risk of liver resection in elderly patients are discussed here. Comparative data are also presented on the mortality, morbidity and post-operative changes in blood chemistry parameters in 90 patients who underwent hepatic resection: 33 patients over 65 years of age (group A) and 57 under 65 years (group B). In group A, compared to group B, mortality (3% versus 5%) and the percentage of patients with post-operative complications (27% versus 37%) were not significantly different. The incidence of post-operative complications correlated more closely with specific risk factors (elevated pre-operative "ASA score" from associated disease) than with age itself. Analysis of the regressions did not reveal important relationships between age and changes in the blood chemistry parameters. These results help to support the idea that advanced age alone is not now an absolute contra-indication to major liver resection.

Calculation of venoarterial CO2 concentration difference.

Quantitative relationships in CO2 transport and exchange processes were combined for use as the basic components of an original mathematical model for the calculation of venoarterial blood CO2 concentration difference (v-aDCO2). This is calculated as the sum of the increment in CO2 concentration (CCO2) related to the increase in CO2 tension (delta P) from arterial to venous value at constant O2 saturation (delta CCO2/delta P) and of the increment in CO2 concentration related to the decrease in O2 saturation (delta S) from arterial to venous value at constant CO2 tension (delta CCO2/delta S). The newly developed relationships correlated well with the experimental data from which they were derived (r2 = 0.94-0.99). The results provided by the model compared remarkably well with the results of previously published measurements (r2 = 0.96-0.99). This new model allows one to overcome some of the limitations implicit in previously available methods and provides a useful tool for the assessment and monitoring of hemodynamic, metabolic, and O2-CO2 exchange patterns in whole body and regional vascular beds.

Substrate supply as determinant of O2 extraction in sepsis and nonseptic trauma.

Metabolic and hemodynamic measurements performed in 72 septic (S) and 40 nonseptic (NS) surgical patients undergoing total parenteral nutrition were analyzed to assess the role of substrate supply as a determinant of O2 extraction (O2Ex). In S, O2Ex was inversely related to cardiac index (CI); at any given CI, significant increases in O2Ex with simultaneous increases in O2 consumption (VO2) were related to increasing doses of amino acids, with a less remarkable effect of fat and no effect of glucose dose. In NS, O2Ex was also inversely related to CI; however, at any given CI, there was no evident substrate-supply dependency of O2Ex, which was more normally related to P50. The increase in VO2 per gram of administered amino acids, at any CI and O2 transport index, was 817 ml in S and 267 ml in NS. These results suggest that the impaired O2Ex and VO2 in S may at least partly reflect abnormalities in substrate utilization and that amino acid support may have a role in modulating these abnormal O2Ex patterns by providing preferential substrate for oxidative metabolism.

Dependency of the O2 consumption/O 2 transport relationship on amino acid supply in sepsis.

In sepsis tissue O2 uptake may be abnormally limited because of a depressed O2 consumption/O2 transport relationship. This study has been performed to assess patterns of O2 consumption, CO2 production and O2 transport in septic patients undergoing total parenteral nutrition; more in particular, this study has investigated the interdependence between the patterns of blood O2 uptake and simultaneous CO2 release, and the availability of substrates (amino acids, glucose and fat). It has been shown that the O2 consumption/O2 transport relationship is significantly influenced by the exogenous amino acid load, which tends to increase O2 uptake and O2 consumption at any given O2 transport, thus suggesting a favourable effect of amino acid administration on energy metabolism. The data on CO2 production and CO2 release, in addition to reconfirming the results of previous studies, have shown that the changes in O2 uptake and in CO2 production mediated by substrate doses have a quantifiable impact on blood O2-CO2 exchange interactions.

Relationship of plasma cholesterol level to doses of branch-chain amino acids in sepsis.

Plasma cholesterol levels, plasma lactate, and total body RQ were measured in septic patients undergoing total parenteral nutrition (TPN) with glucose, fat, and two different branch-chain amino acid admixtures (49% BCAA and 16% BCAA). Mean plasma cholesterol for all measurements (2.61 +/- 0.94 [SD] mmol/L) was lower than normal; however, it was higher with 49% BCAA than with 16% BCAA (2.94 +/- 0.95 vs. 2.27 +/- 0.81 mmol/L, p less than .001) for comparable loads of glucose, fat, and total amino acids. Plasma lactate and RQ were lower with 49% BCAA than with 16% BCAA (p less than .001 for both). Cholesterol was directly related to the absolute dose of BCAA (p less than .001), was unrelated to the dose of non-BCAA, and was inversely related to lactate (p less than .001). These results suggest that BCAA ketoacids contribute to cholesterol synthesis in sepsis, as well as being an oxidative source. The data also suggest that the reduction in alanine in BCAA-enriched amino-acid TPN assists in the lowering of plasma lactate secondary to abnormal septic glucose metabolism.

Noninvasive surveillance of allografted kidneys by ultrasonic duplex scanning.

Over a one-year period 1,000 duplex Doppler evaluations were performed in 70 patients submitted to kidney transplantation for end-stage renal failure. Duplex monitoring was performed to evaluate transplant status from hemodynamic patterns of the graft arteries. A duplex scanner with a 3.75 MHz sector transducer was used; pulsed Doppler was utilized to detect blood flow velocities in the main renal, segmental, interlobar and arcuate arteries. Arterial signals were quantified through a pulsatility index (PI). Three cases of acute rejection (AR), 9 cases of chronic rejection (CR), 2 cases of cyclosporine nephrotoxicity (Csa Tox), and 4 cases of acute tubular necrosis (ATN) were recognized and biopsy proved. At each arterial site PI values of normally functioning allografts were lower than 1.5; AR patients showed PI values ranging from 1.7 to 3.1, promptly lowered by immunosuppressive treatment. CR patients had a spectrum of PI from 0.5 to 3.1. Patients with Csa Tox and ATN showed in all the explored sites normal arterial signals and thus normal PI values. PI variations reflect even slight blood flow reductions due to immunologically mediated increases in intrarenal arterial resistances. Duplex sonography of allografted kidneys shows great diagnostic attitudes in the noninvasive characterization of transplant malfunction.

Impact of fat and glucose administration on metabolic and respiratory interactions in sepsis.

Metabolic and respiratory interactions were analyzed in a large group of septic patients (S) and in a reference group of nonseptics (NS) during the iv administration of glucose and fat. In spite of a moderate increase in CO2 production (VCO2) observed during the administration of fat in S, a VCO2-sparing effect of fat, with respect to equicaloric amounts of glucose, was reconfirmed. The relevance of the therapeutic modulation of CO2 production during parenteral nutrition, and the relative impact on the abnormal septic respiratory patterns, were emphasized by analyzing the physiological relationships and mechanisms responsible for the increase in respiratory work in sepsis.