Computerized correction of blood base excess to full hemoglobin-O2 saturation.

BACKGROUND AND OBJECTIVE: A mathematical procedure was developed to obtain an accurate coefficient (-∆BEB) for the correction of blood base excess to full hemoglobin-O2 saturation taking into account actual 2,3-diphosphoglycerate (2,3-DPG) concentration. METHODS: Previously published laboratory data were carefully processed through regression analysis, by correlating laboratory measurements of -∆BEB with the corresponding values of plasma pH, CO2 tension and 2,3-DPG. RESULTS: Data processing allowed the development of two accurate fits to the original laboratory results for blood with normal 2,3-DPG and for blood depleted of 2,3-DPG (r2 = 0.990 and 0.986, respectively, p < 0.0001 for both), as the main components of a procedure for estimating the correction factor in normal conditions and in moderate-to-extreme illness with extreme acid-base abnormalities. CONCLUSIONS: This regression-derived procedure can easily integrate any computer system to automatically obtain an accurate correction factor on the basis of plasma pH, CO2 tension, and 2,3-DPG concentration if available. It may also allow for the assessment of small stoichiometric quantities involved in O2-linked H+ exchange and equilibrium (Haldane effect) in computer programs dedicated to these types of investigations.

Increased ratio of P[v-a]CO2 to C[a-v]O2 without global hypoxia: the case of metformin-induced lactic acidosis.

The ratio of venoarterial CO2 tension to arteriovenous O2 content difference (P[v-a]CO2/C[a-v]O2) increases when lactic acidosis is due to inadequate oxygen supply (hypoxia); we aimed to verify whether it also increases when lactic acidosis develops because of mitochondrial dysfunction (dysoxia) with constant oxygen delivery. Twelve anaesthetised, mechanically ventilated pigs were intoxicated with IV metformin (4.0 to 6.4 g over 2.5 to 4.0 h). Saline and norepinephrine were used to preserve oxygen delivery. Lactate and P[v-a]CO2/C[a-v]O2 were measured every one or two hours (arterial and mixed venous blood). During metformin intoxication, lactate increased from 0.8 (0.6-0.9) to 8.5 (5.0-10.9) mmol/l (p < 0.001), even if oxygen delivery remained constant (from 352 ± 78 to 343 ± 97 ml/min, p = 0.098). P[v-a]CO2/C[a-v]O2 increased from 1.6 (1.2-1.8) to 2.3 (1.9-3.2) mmHg/ml/dl (p = 0.004). The intraclass correlation coefficient between lactate and P[v-a]CO2/C[a-v]O2 was 0.72 (p < 0.001). We conclude that P[v-a]CO2/C[a-v]O2 increases when lactic acidosis is due to dysoxia. Therefore, a high P[v-a]CO2/C[a-v]O2 may not discriminate hypoxia from dysoxia as the cause of lactic acidosis.

Erratum to "Prognostic Role of Serum Amino Acids in Head and Neck Cancer".

[This corrects the article DOI: 10.1155/2020/2291759.].

Prognostic Role of Serum Amino Acids in Head and Neck Cancer.

INTRODUCTION: Serum amino acid (AA) profiles represent a valuable tool in the metabolic assessment of cancer patients; still, information on the AA pattern in head and neck cancer (HNC) patients is insufficient. The aim of the study was to assess whether serum AA levels were associated with the stage of neoplastic disease and prognosis in primary HNC patients. METHODS: Two hundred and two primary HNC patients were included in the study. Thirty-one AAs and derivatives were measured in serum through an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). The association between AA concentrations and the stage (advanced versus early) of HNC was estimated using a multivariable logistic regression model. A multivariable Cox regression model was used to evaluate the prognostic significance of each AA. RESULTS: At the multivariable logistic regression analysis, increased levels of alpha-aminobutyric acid, aminoadipic acid, histidine, proline, and tryptophan were associated with a reduced risk of advanced stage HNC, while high levels of beta-alanine, beta-aminobutyric acid, ethanolamine, glycine, isoleucine, 4-hydroxyproline, and phenylalanine were associated with an increased risk of advanced stage HNC. Furthermore, at multivariate analysis, increased levels of alpha-aminobutyric acid were associated with increased overall survival (OS), while high levels of arginine, ethanolamine, glycine, histidine, isoleucine, 4-hydroxyproline, leucine, lysine, 3-methylhistidine, phenylalanine, and serine were associated with decreased OS. CONCLUSIONS: Our study suggests that AA levels are associated with the stage of disease and prognosis in patients with HNC. More study is necessary to evaluate if serum AA levels may be considered a hallmark of HNC and prove to be clinically useful markers of disease status and prognosis in HNC patients.

Hypotransferrinemia and changes in plasma lipid and metabolic patterns in sepsis.

This study was performed to obtain a characterization of the changes in plasma transferrin (Tf, g/L) in sepsis. More than four hundred determinations of Tf, and of a large series of simultaneously collected blood and hemodynamic variables, were obtained in 17 patients with post-traumatic sepsis. Tf during sepsis was consistently low (mean +/- SD = 1.46 +/- 0.46) however fluctuated markedly according to changes in metabolic and hemodynamic patterns. Regression analysis showed that decreases in Tf were simultaneously correlated with the plasma lipid pattern (in particular with decreasing cholesterol and increasing triglycerides), with decreases in albumin and peripheral O2 extraction, and with increasing cardiac index (p < 0.001 for all). Decreases in Tf were moderated by increasing the parenteral amino acid dose (p < 0.001). Combinations of these variables in multiple regressions explained nearly 80% of the variability of Tf. There were no similar correlations for other acute phase proteins except ceruloplasmin, which showed opposite changes compared to those of Tf. These results show that within the hypotransferrinemia which characterizes sepsis, Tf may oscillate remaining strongly correlated with changes in metabolic and hemodynamic patterns, which may account for nearly 80% of the variability of Tf.

External lymphatic fistula after intra-abdominal lymphadenectomy for cancer. Treatment with total parenteral nutrition and somatostatin.

OBJECTIVE: External lymphatic fistula or chyloperitoneum after intra-abdominal lymphadenectomy may present challenging problems. In the absence of definite guidelines the choice of treatment is often empirical, with unpredictable effectiveness, and the reporting of new cases may broaden the available experience. METHODS: We describe two cases. One patient had high-output external fistula (1300 mL/d) after para-aortic lymphadenectomy for metastatic lymph nodes. The fistula became fully evident at postoperative day 4, with resumption of an oral diet, on the basis of a 1300-mL/d output of white milky fluid from an abdominal drainage. Oral feeding was interrupted and total parenteral nutrition was started; this was transiently associated with octreotide administration, subsequently replaced by somatostatin. The second patient had a low-output fistula (350 mL/d) after liver resection and lymphadenectomy for cholangiocarcinoma and underwent treatment with total parenteral nutrition and somatostatin. RESULTS: In the first case the lymphatic fistula healed in just less than 3 wk, with the patient constantly remaining in very good condition, without secondary complications. In the second case the low-output fistula healed more rapidly. CONCLUSION: Interruption of oral feeding with total parenteral nutrition and continuous somatostatin infusion was an effective treatment in both patients with an intra-abdominal lymphatic leak.

Clinical use of plasma chitotriosidase in severe sepsis.

Plasma chitotriosidase activity (ChT) was previously proposed to quantify severity of sepsis. In a complex surgical case, with prolonged sepsis and consistently high ChT, we found that the least increased values occurred in stages of extreme illness, with profound hypocholesterolemia. ChT needs better characterization before becoming a reliable biomarker of septic evolution.

Comparison of two methods to assess blood CO2 equilibration curve in mechanically ventilated patients.

In order to compare two mathematical methods to assess the blood CO2 equilibration curve from a single blood gas analysis [Loeppky, J.A., Luft, U.C., Fletcher, E.R., 1983. Quantitative description of whole blood CO2 dissociation curve and Haldane effect. Resp. Physiol. 51, 167-181; Giovannini, I., Chiarla, C., Boldrini, G., Castagneto, M., 1993. Calculation of venoarterial CO2 concentration difference. J. Appl. Physiol. 74, 959-964], arterial and central venous blood gas analyses and oximetry were performed before and after ventilatory resetting, at constant arterial O2 saturation, in 12 mechanically ventilated patients. CO2 equilibration curves obtained from basal arterial blood gas analyses were used to predict arterial CO2 content after ventilatory resetting and vice versa. Internal consistency was very good for both methods and comparable. Method 2 also yielded excellent predictions of changes of arterial pH associated with ventilatory resetting. In determining Haldane effect, method 2 yielded very stable results within the expected range of values, while method 1 yielded a wider spread of results. Method 2 appeared more suitable to determine the Haldane effect in the conditions of the study, probably due to an approach minimizing the effect of potential sources of inaccuracy.

Non-surgical management of a lymphatic fistula, after laparoscopic colorectal surgery, with total parenteral nutrition, octreotide, and somatostatin.

OBJECTIVE: We report the case of an external lymphatic fistula that appeared through an abdominal drainage after laparoscopic resection of the rectum and sigmoid colon for cancer, with lymphadenectomy. There was no chylous ascites because of controlled external drainage. METHODS: The fistula was managed conservatively by interruption of oral feeding and administration of total parenteral nutrition and subcutaneous octreotide and management then shifted to intravenous somatostatin, with decreased lymph output through the fistula to 100 to 200 mL/d. RESULTS AND CONCLUSION: Somatostatin seemed to be more effective than subcutaneous octreotide. At postoperative day 18, refusal of treatment by the patient with oral resumption of clear liquids resulted in a transient increase in lymph output to 600 mL/d, and treatment was resumed. Subsequently, progressive withdrawal of the abdominal drainage was associated with complete healing of the fistula. The drain was removed at day 28, treatment was interrupted at day 30 after verifying by ultrasound the absence of chyloperitoneum, and the patient was discharged without further problems.

Pathophysiologic and clinical correlates of hypophosphatemia and the relationship with sepsis and outcome in postoperative patients after hepatectomy.

Hypophosphatemia in critically ill and postoperative (p.o.) patients is a multifactorial event, and is also related to severity of illness. This study was conducted to assess pathophysiologic correlates of hypophosphatemia and the simultaneous relationship with clinical events after hepatectomy. A total of 333 measurements were obtained in 59 patients: these were performed preoperatively and at p.o. days 1, 3, and 7 in all patients, and subsequently, until recovery or death, only in those with complications. Measurements included plasma phosphate together with a large number of additional blood chemistries, taking into account primary and associated diseases, events associated with the operation, doses of parenteral substrates, occurrence of sepsis or other p.o. complications, outcome, and a consistent set of complementary variables. Plasma phosphate decreased at p.o. days 1 and 3 (P < 0.001) and retumed to a level close to baseline at p.o. day 7. Regression analysis showed that phosphate was related simultaneously to patient age (inversely), levels of creatinine and potassium (directly), and dose of parenteral amino acids (inversely; P < 0.001 for all). Independently of covariation with these variables, there was a decrement in phosphate at p.o. days 1 and 3 that was related specifically to p.o. condition; this decrement had a general component common to all patients, an additional component related to duration of previous hepatic ischemia at surgery, and a further component predictive of the subsequent development of complications (in most cases, sepsis). Plasma phosphate at p.o. day 1 was related inversely to APACHE II score (r2 = 0.4, P < 0.001), and levels lower than 1.5 mg/dL were associated with an almost 4-fold increase in the rate of complications compared with cases with higher phosphate (P < 0.001). The best single variable bridging early evidence of hypophosphatemia to subsequent development of complications was plasma cholesterol, which fell significantly from p.o. day 3 onward in patients with complications compared with those recovering normally (P < 0.01), and in nonsurvivors compared with survivors (P < 0.01). Hypophosphatemia may anticipate clinical evidence of complications by reflecting an early stronger acute-phase response, with shift of phosphate from intra- to extravascular space, or true phosphorus deficiency, which may favor development of complications by impairing high-energy substrate availability for host defense and other cell functions.

High phosphoserine in sepsis: panel of clinical and plasma amino acid correlations.

The determination of plasma phosphoserine concentration in sepsis is uncommon, and the clinical and metabolic correlations of abnormally high phosphoserine are basically unknown. We analyzed 430 determinations of phosphoserine, other amino acid (AA) levels and ancillary variables obtained in 18 septic patients, in order to assess the biochemical and clinical correlations of changes in phosphoserine. Phosphoserine ranged between 5 and 55 micromol/L (n.v. < 12). Increasing phosphoserine was associated with higher severity of illness and death, and its best AA correlates were increasing cystathionine, 3-methylhistidine, histidine, hydroxyproline and tyrosine (r > 0.65, p < 0.001 for all). High phosphoserine seemed to cumulatively reflect kidney and liver dysfunction and enhanced proteolysis. As a collateral finding, 3-methylhistidine (a best correlate of phosphoserine) was also inversely related to nutritional AA dose (p < 0.001). These data suggest that in septic patients the determination of plasma phosphoserine may provide useful information on severity of septic illness and prognosis. The observed correlations also indirectly evidenced an impact of nutritional AA dose in moderating proteolysis.

Parenteral nutrition in liver resection.

Albeit a very large number of experiments have assessed the impact of various substrates on liver regeneration after partial hepatectomy, a limited number of clinical studies have evaluated artificial nutrition in liver resection patients. This is a peculiar topic because many patients do not need artificial nutrition, while several patients need it because of malnutrition and/or prolonged inability to feeding caused by complications. The optimal nutritional regimen to support liver regeneration, within other postoperative problems or complications, is not yet exactly defined. This short review addresses relevant aspects and potential developments in the issue of postoperative parenteral nutrition after liver resection.