Effect of a quality improvement program on compliance to the sepsis bundle in non-ICU patients: a multicenter prospective before and after cohort study

Objective

Sepsis and septic shock are major challenges and economic burdens to healthcare, impacting millions of people globally and representing significant causes of mortality. Recently, a large number of quality improvement programs focused on sepsis resuscitation bundles have been instituted worldwide. These educational initiatives have been shown to be associated with improvements in clinical outcomes. We aimed to evaluate the impact of a multi-faceted quality implementing program (QIP) on the compliance of a "simplified 1-h bundle" (Sepsis 6) and hospital mortality of severe sepsis and septic shock patients out of the intensive care unit (ICU).

Methods

Emergency departments (EDs) and medical wards (MWs) of 12 academic and non-academic hospitals in the Lombardy region (Northern Italy) were involved in a multi-faceted QIP, which included educational and organizational interventions. Patients with a clinical diagnosis of severe sepsis or septic shock according to the Sepsis-2 criteria were enrolled in two different periods: from May 2011 to November 2011 (before-QIP cohort) and from August 2012 to June 2013 (after-QIP cohort).

Measurements and main results

The effect of QIP on bundle compliance and hospital mortality was evaluated in a before-after analysis. We enrolled 467 patients in the before-QIP group and 656 in the after-QIP group. At the time of enrollment, septic shock was diagnosed in 50% of patients, similarly between the two periods. In the after-QIP group, we observed increased compliance to the "simplified rapid (1 h) intervention bundle" (the Sepsis 6 bundle - S6) at three time-points evaluated (1 h, 13.7 to 18.7%, p = 0.018, 3 h, 37.1 to 48.0%, p = 0.013, overall study period, 46.2 to 57.9%, p < 0.001). We then analyzed compliance with S6 and hospital mortality in the before- and after-QIP periods, stratifying the two patients' cohorts by admission characteristics. Adherence to the S6 bundle was increased in patients with severe sepsis in the absence of shock, in patients with serum lactate <4.0 mmol/L, and in patients with hypotension at the time of enrollment, regardless of the type of admission (from EDs or MWs). Subsequently, in an observational analysis, we also investigated the relation between bundle compliance and hospital mortality by logistic regression. In the after-QIP cohort, we observed a lower in-hospital mortality than that observed in the before-QIP cohort. This finding was reported in subgroups where a higher adherence to the S6 bundle in the after-QIP period was found. After adjustment for confounders, the QIP appeared to be independently associated with a significant improvement in hospital mortality. Among the single S6 procedures applied within the first hour of sepsis diagnosis, compliance with blood culture and antibiotic therapy appeared significantly associated with reduced in-hospital mortality.

Conclusion

A multi-faceted QIP aimed at promoting an early simplified bundle of care for the management of septic patients out of the ICU was associated with improved compliance with sepsis bundles and lower in-hospital mortality.

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

Early caloric deficit is associated with a higher risk of death in invasive ventilated COVID-19 patients

BACKGROUND & AIMS

The aim of this study was to evaluate the nutritional support management in mechanically ventilated coronavirus disease 2019 (COVID-19) patients and explore the association between early caloric deficit and mortality, taking possible confounders (i.e. obesity) into consideration.

METHODS

This was a prospective study carried out during the first pandemic wave in the intensive care units (ICUs) of two referral University Hospitals in Lombardy, Italy. Two hundred twenty-two consecutive mechanically ventilated COVID-19 patients were evaluated during the ICU stay. In addition to major demographic and clinical data, we recorded information on the route and amount of nutritional support provided on a daily basis.

RESULTS

Among patients still in the ICUs and alive on day 4 (N = 198), 129 (65.2%) and 72 (36.4%) reached a satisfactory caloric and protein intake, respectively, mainly by enteral route. In multivariable analysis, a satisfactory caloric intake on day 4 was associated with lower mortality (HR = 0.46 [95%CI, 0.42-0.50], P < 0.001). Mild obesity (body mass index [BMI] ≥30 and < 35 kg/m²) was associated with higher mortality (HR = 1.99 [95%CI, 1.07-3.68], P = 0.029), while patients with moderate-severe obesity (BMI≥35 kg/m²) were less likely to be weaned from invasive mechanical ventilation (HR = 0.71 [95%CI, 0.62-0.82], P < 0.001).

CONCLUSIONS

This study confirmed the negative prognostic and clinical role of obesity in mechanically ventilated COVID-19 patients and suggested that early caloric deficit may independently contribute to worsen survival in this patients' population. Therefore, any effort should be made to implement an adequate timely nutritional support in all COVID-19 patients during the ICU stay.

Factors Associated With Severity of Delirium Complicating COVID-19 in Intensive Care Units

The clinical outcome of the disease provoked by the SARS-CoV-2 infection, COVID-19, is largely due to the development of interstitial pneumonia accompanied by an Acute Respiratory Distress Syndrome (ARDS), often requiring ventilatory support therapy in Intensive Care Units (ICUs). Current epidemiologic evidence is demonstrating that the COVID-19 prognosis is significantly influenced by its acute complications. Among these, delirium figures as one of the most frequent and severe, especially in the emergency setting, where it shows a significantly negative prognostic impact. In this regard, the aim of our study is to identify clinical severity factors of delirium complicating COVID-19 related-ARDS. We performed a comparative and correlation analysis using demographics, comorbidities, multisystemic and delirium severity scores and anti-delirium therapy in two cohorts of ARDS patients with delirium, respectively, due to COVID-19 (n = 40) or other medical conditions (n = 39). Our results indicate that delirium in COVID-19-related ARDS is more severe since its onset despite a relatively less severe systemic condition at the point of ICU admission and required higher dosages of antipsychotic and non-benzodiazepinic sedative therapy respect to non-COVID patients. Finally, the correlation analysis showed a direct association between the male gender and maximum dosage of anti-delirium medications needed within the COVID-19 group, which was taken as a surrogate of delirium severity. Overall, our results seem to indicate that pathogenetic factors specifically associated to severe COVID-19 are responsible for the high severity of delirium, paving the way for future research focused on the mechanisms of the cognitive alterations associated with COVID-19.

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background

Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies.

Methods

In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality.

Findings

Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference –1·69 [–9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5–8] vs 6 [5–8] cm H₂O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52–23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75–0·86]; p<0·0001).

Interpretation

Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status.

Funding

No funding.

Endothelial damage in septic shock patients as evidenced by circulating syndecan-1, sphingosine-1-phosphate and soluble VE-cadherin: a substudy of ALBIOS

Background

Septic shock is characterized by breakdown of the endothelial glycocalyx and endothelial damage, contributing to fluid extravasation, organ failure and death. Albumin has shown benefit in septic shock patients. Our aims were: (1) to identify the relations between circulating levels of syndecan-1 (SYN-1), sphingosine-1-phosphate (S1P) (endothelial glycocalyx), and VE-cadherin (endothelial cell junctions), severity of the disease, and survival; (2) to evaluate the effects of albumin supplementation on endothelial dysfunction in patients with septic shock.

Methods

This was a retrospective analysis of a multicenter randomized clinical trial on albumin replacement in severe sepsis or septic shock (the Albumin Italian Outcome Sepsis Trial, ALBIOS). Concentrations of SYN-1, S1P, soluble VE-cadherin and other biomarkers were measured on days 1, 2 and 7 in 375 patients with septic shock surviving up to 7 days after randomization.

Results

Plasma concentrations of SYN-1 and VE-cadherin rose significantly over 7 days. SYN-1 and VE-cadherin were elevated in patients with organ failure, and S1P levels were lower. SYN-1 and VE-cadherin were independently associated with renal replacement therapy requirement during ICU stay, but only SYN-1 predicted its new occurrence. Both SYN-1 and S1P, but not VE-cadherin, predicted incident coagulation failure. Only SYN-1 independently predicted 90-day mortality. Albumin significantly reduced VE-cadherin, by 9.5% (p = 0.003) at all three time points.

Conclusion

Circulating components of the endothelial glycocalyx and of the endothelial cell junctions provide insights into severity and progression of septic shock, with special focus on incident coagulation and renal failure. Albumin supplementation lowered circulating VE-cadherin consistently over time.

Clinical Trial Registration: ALBIOS ClinicalTrials.gov number NCT00707122.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03545-1.

A spectroscopic and molecular dynamics study on the aggregation process of a long-acting lipidated therapeutic peptide: the case of semaglutide

The aggregation properties of semaglutide, a lipidated peptide drug agonist of the Glucagon-like peptide 1 receptor recently approved for the treatment of type 2 diabetes, have been investigated by spectroscopic techniques (UV-Vis absorption, steady-state and time-resolved fluorescence, and electronic circular dichroism) and molecular dynamics simulations. We show that in the micromolar concentration region, in aqueous solution, semaglutide is present as monomeric and dimeric species, with a characteristic monomer-to-dimer transition occurring at around 20 μM. The lipid chain stabilizes a globular morphology of the monomer and dimer species, giving rise to a locally well-defined polar outer surface where the lipid and peptide portions are packed to each other. At very long times, these peptide clusters nucleate the growth of larger aggregates characterized by blue luminescence and a β-sheet arrangement of the peptide chains. The understanding of the oligomerization and aggregation potential of peptide candidates is key for the development of long acting and stable drugs.

Evaluation of Real Time PCR Aspergillus spp. in bronchoalveolar lavage samples

The present study investigated the improvement in the diagnosis of invasive pulmonary aspergillosis (IPA) adding a molecular test on bronchoalveolar lavage (BAL) to the routine diagnostic approach including microscopy, culture and galactomannan (GM) immunoassay. A total of 133 BAL samples were retrospectively tested for the Aspergillus DNA: 112 samples were from immunocompromised patients at risk of invasive fungal infection and 21 were from patients not at risk and without clinical evidence of IPA. The latter samples were used to identify the cut-off of positivity for the molecular test. Applying the cut-off quantity of 50 copies/reaction, the PCR test had 90% sensitivity and 97% specificity and resulted the most sensitive, specific and accurate among those evaluated. The statistical analysis showed that the probability that a patient is not affected by IPA is 99% when the three tests (PCR, GM and culture) are concordantly negative.

Effects of recombinant human activated protein C on the fibrinolytic system of patients undergoing conventional or tight glycemic control

AIM

Recombinant human activated protein C (rh-APC) and tight glycemic control (TGC) have been shown to reduce mortality in septic patients. Both interventions can reduce the plasma concentration and/or activity of the most powerful suppressor of fibrinolysis, plasminogen activator inhibitor-1 (PAI-1). Our aim was to evaluate the effects on the fibrinolytic system after the administration of rh-APC in septic patients undergoing conventional or TGC.

METHODS

Posthoc analysis of data was collected from 90 patients with severe sepsis/septic shock, randomized to either conventional or TGC groups. Independent of these treatments, patients with at least two organ dysfunctions simultaneously received rh-APC. Plasma levels of multiple biochemical markers for fibrinolysis, coagulation, and inflammation were determined every day for the 1st week and then on study days 9, 11, 13, 18, 23, and 28. Clinical data and sepsis-related organ failure assessment (SOFA) scores were also recorded.

RESULTS

Patients who had received rh-APC exhibited significantly more impairments in fibrinolysis at baseline (PAI-1 activity 49.76 [24.61-71.82] vs 21.92 [6.47-55-83] IU/mL, P=0.03). The reductions in plasma PAI-1 activity over time associated with rh-APC treatment were different according to whether the treatment was administered to patients undergoing conventional or TGC (P=0.01). However, the most prominent reductions were in patients undergoing conventional glycemic control. Significant interactions between the two study interventions were also found for PAI-1 concentration (P<0.001), C-reactive protein (P=0.02), and interleukin-6 levels (P<0.001).

CONCLUSIONS

Both rh-APC and TGC appear to improve fibrinolysis in septic patients. The reduction in the impairment of fibrinolysis associated with rh-APC treatment seems greater in patients undergoing conventional glycemic control than in those undergoing TGC.

Heat stress: characteristics, pathophysiology and avoidable mistakes

In August 2003 an exceptional heatwave was recorded in Europe. The authors would like to describe 6 patients for which the intensivist was called as a consultant. All patients had a skin temperature >40 degrees C, central nervous system impairment, severe hyponatremia [124.7 mEq/l+/-5.6 (range 117-130)] and severe metabolic acidosis [BE -6.28 mEq/l+/-3.55 (range -9.5-0), HCO3- 17.75 mEq/l+/-3.25 (range 13.4-21.9)]. All patients had decreased platelet count and coagulation abnormalities. Two patients were hypertensive, 4 hypotensive. The heat stress due to the hot environment is characterized by systemic inflammatory response (as in severe sepsis) and hemodynamic impairment (as in hypovolemic shock). The association between hypovolemia and altered microcirculation leads to cell energy failure with metabolic lactic acidosis. The energy failure may induce structural irreversible damage of mitochondria. It is possible to differentiate, during energy failure, the irreversible or reversible condition by volume loading and vasoactive drugs challenge tests. In fact, if the hemodynamic correction is associated with normalization of SvO2 with disappearance of metabolic acidosis, this suggests hemodynamic impairment with intact mitochondrial function. In contrast, if the hemodynamic improvement with normalization of SvO2 is associated and acidosis persists, this suggests irreversible structural mitochondrial damage. The threshold between reversibility and irreversibility is likely time dependent, as suggested by biochemical consideration and by 2 large randomized studies on hemodynamic treatment. The comparative analysis of these 2 studies suggests that the time of intervention may lead to significant differences in mortality. In these patients time is essential.

A blunt complex abdominal trauma: total hepatectomy and liver transplantation

A victim of a motor accident was referred to the Emergency Department. He was unconscious, breathing was rapid and shallow, and had a mean arterial pressure of 60 mmHg with a distended abdomen. A peritoneal lavage was positive for blood. An immediate laparotomy showed a massive hepatic injury with bilobar disruptions. After an unsuccessful hepatorrhaphy an extensive perhepatic gauze packing was done. During the operation the patient was massively transfused and high doses of dopamine were used. At the end a relative stability was reached, but a few hours later, due to the high risk of sepsis and abdominal compartment syndrome, a second laparotomy was performed. Despite efforts to reach a good hemostasis, it was decided to perform a total hepatectomy and portocaval shunt. The patient was put on the waiting list for a compatible liver. After 36 h in this anhepatic state, the patient received the new graft. The graft showed immediate recovery. In cases of severe and complex liver trauma, performing a total hepatectomy followed by liver transplantation is justified.

[Neurologic prognosis after cardiocirculatory arrest outside the hospital]

OBJECTIVE

To detect clinical signs and times of evaluation able to identify patients with good neurologic prognosis after out-of-hospital cardiac arrest.

EXPERIMENTAL DESIGN

Retrospective study with 6 months-2 years of follow-up.

SETTING

General intensive care unit, from 1993 to 1995.

PATIENTS

Twenty-three patients aged 18-80 years, admitted with coma after out-of-hospital cardiac arrest, who survived at least 24 hours, without concomitant neurologic disorders.

INTERVENTIONS

Neurologic outcome classification in three categories: complete neurologic recovery (A), moderate to severe disability (B), death without regained consciousness (C); A and B groups of patients are considered together as a "good neurologic outcome" group.

MEASUREMENTS

Evaluation of some neurological parameters (GCS, motor response to pain, spontaneous motility, cranial nerve reflexes, spontaneous breathing, seizures) 6 hours (t0), 24 hours (t1), 72 hours (t2) and 7 days (t3) after arrest.

RESULTS

Patients with good prognosis are identified with 100% sensitivity from the following parameters: at t0 none; at t1 motor response to pain, GCS > 4, absence of seizures; at t2 the former parameters, spontaneous breathing, brain stem reflexes, normal pupils; at t3 all the former parameters and spontaneous motility. Specificity is greater than 50% only for motor response to pain and GCS > 4.

CONCLUSIONS

It is mostly impossible to state a neurologic prognosis in the first hours after cardiac arrest. The single predictor with the most reliable prognostic value is motor response to pain which allows, if present, to identify all the patients with a good prognosis as early as 24 hours after arrest.

Early metabolic treatment after liver transplant: amino acid tolerance

OBJECTIVE

We investigated the amino acid (AA) tolerance during Total Parenteral Nutrition (TPN) in adult patients undergone liver transplant (LTX).

DESIGN

The treatment (Glucose and AA), induced on the 2nd postoperative day, was later maintained with 27 kcal/kg Ideal Body Weight (IBW) as glucose and 0.12 (12 patients: protocol #1), 0.18 (10 patients: protocol #2) and 0.25 g nitrogen (N)/kg IBW (13 patients: protocol #3) till end of the 6th postoperative day. The N intake was sequentially modified in protocol #2 and #3 to increase the supply of the amino acid (AA) that resulted in an infusion plasma level below the expected "normal" range (between 1 and 1.6 times the overnight fasting plasma level of volunteer).

PATIENTS

35 consecutive adult patients without diabetes and organ failures for the entire study period.

MEASUREMENTS

Plasma AA profile was measured before LTX and at the last TPN day under continuous infusion. During #1 and #2 protocol, many AA resulted below or at the lower range of the norm while, during 0.25 gN/kg IBW infusion, the majority of the administered AA significantly increased with respect to reference values. Nevertheless, they remained in the "normal" plasma range indicating that they were supplied in an optimal amount (particularly the aromatic and sulphurated ones, potentially toxic if liver function is impaired, and the branched chain AA (BCAA) given at consistent dosage: 0.5 g/kg). Arginine resulted significantly increased (Arg: 1.9 times the reference) and cystine (Cys: 0.45), serine (Ser: 0.8) and taurine (Tau: 0.85) remained significantly lower than "normal" as well as the not administered citrulline (Cit: 0.58) and alfa amino butyric acid (Aba: 0.41). The AA (and calorie) load almost balanced the N losses during the 5th (0.411 +/- 0.038) and 6th study day (0.305 +/- 0.019 gN/kg).

CONCLUSIONS

0.25 gN/kg could be considered the minimum N load in the uncomplicated adult LTX recipients, for reassuring a balanced plasma AA pattern and body N turnover in the early postoperative phase.

Kinetic of body nitrogen loss during a whole day infusion and withdrawal of glucose and insulin in injured patients

OBJECTIVE

To investigate the kinetics of body nitrogen (N) excretion during 24 h glucose infusion (relating glycemia with insulin supply) and during subsequent 24 h saline infusion in injured patients during a full blown stress reaction. To define the lag time between the start of the withdrawal of glucose and insulin infusion, and the modification in the N loss from the body, and the time span to reach the maximum effect and its size. The knowledge of these variables is mandatory to plan short term studies in critically ill patients, while assuring the stability of the metabolic condition during the study period, and also to assess the possible weaning of the effect on protein breakdown during prolonged glucose and insulin infusion.

DESIGN

24-36 h after injury, patients were fasted ( < 100 g glucose) for 24 h (basal day). Thereafter, a 24 h glucose infusion in amount corresponding to measured fasting energy production rate (EPR), clamping glycemia at normal level with insulin supply followed by 24 h saline infusion, was performed. Total N, urea and 3-methyl-histidine (3-MH) in urine were measures on 4 h samples starting from 20th h of the basal day.

SETTING

Multipurpose ICU in University Hospital.

PATIENTS

6 consecutive patients who underwent accidental and/or surgical injury, immediately admitted for respiratory assistance (FIO2 < 0.04). Excluded patients were those with abnormal nutritional status, cardiovascular compromise and organ failures.

MAIN RESULTS

Patients showed a 33% increase in measured versus predicted fasting EPR and a consistent increase in N and 3-MH urinary loss. An infusion of glucose at 5.95 +/- 0.53 mg/kg x min (97.20 +/- 0.03% of the fasting measured EPR) with 1.22 +/- 0.18 mU/kg x min insulin infusion reduced N and 3-MH loss after a time lag of 12 h. The peak decrease in body N (-36%) and 3-MH loss (-38%) was reached during the first 12 h of glucose withdrawal period. Thereafter, during the following 12 h, the effect completely vanished confirming that it is therapy-dependent and that the metabolic environment of the patients did not change during the three days study period.

CONCLUSION

24 h glucose withdrawal reduces N and 3-MH loss injured patients, the drug-like effect is maintained during the first 12 h of withdrawal and thereafter disappears. The study suggests that at least a 24 h study period is necessary when planning studies exploring energy-protein metabolism relationship in injured patients, and, again 24 h before changing protocol in a crossover study.

Effect of infusion and withdrawl of glucose and insulin on gas exchange in injured ventilated patients

PURPOSE

To evaluate the effect induced on gas exchange and on urea excretion by glucose and insulin infusion in injured patients. The magnitude and time necessary for the full development of the metabolic effect were investigated.

METHODS

Six injured patients were investigated. During the first 24 hours, the fasting period, patients received 1 mg/kg*min of glucose; during the second 24 hours, the treatment period, infusion was increased to about the 95% of the energy production rate; during the last 8 hours, (stop period) the infusion rate was again set to 1 mg/kg*min. Gas exchange was determined in two consecutive 12-hour series, for 30 minutes every hour, either during a stabilized treatment or after its variation. Urea excretion was determinated on 4-hour samples.

RESULTS

With respect to the fasting period, during the last 4 hours of the treatment period, the energy production rate did not vary; urea excretion (-25%) and oxygen consumption (-9%) decreased significantly. Carbon dioxide production (+16%), total respiratory quotient, and minute ventilation (+5%) increased significantly. Carbon dioxide production varied linearly with time (glucose infusion +1.74 mL/min*m2*h, P < .05; glucose withdrawal -1.89 mL/min*m2*h, P < .01). Minute ventilation decreased only during the withdrawal period by 65 mL/min*m2*h (P < .05).

CONCLUSIONS

The infusion of glucose and insulin, in an amount slightly lower than the metabolic expenditure, leads to a consistently reduced amino acid catabolism and to a decreased oxygen consumption, without affecting energy requirements. Although it leads to an increase of carbon dioxide production, the measured change is so small and slow that it is not harmful unless there is severe respiratory insufficiency.

[Determination of the best amino acid input after orthotopic liver transplantation]

Ten-three patients were investigated during the early postoperative phase after orthotopic liver transplantation to assess the adequacy of the amino acid (AA) supply during both parenteral (days 1-5) and enteral (days 6-9) nutrition. Plasma AA profile was determined preoperatively, on day 4 and 5 during TPN and on day 8 and 9 during EN, urea production rate was measured every day. Calories input was 28 kcal.kg-.day as glucose, nitrogen intake was 0.25 g.kg- day, supplying individual AA on the basis of previous studies. Urea nitrogen production during TPN (9-11 gN/m2.day) outlines the ability of the transplanted liver to manage the overall nitrogen load. Individual AA plasma profile was considered the expression of an adequate input when comprised between 1 and 1.5 times the normal value, in this respect we obtained adequate levels of all essential AAs. Particularly phenylalanine, methionine and branched chain AA, critical during liver failure, were kept in this range by supplying 68, 48 and 500 mg.kg-1.day. According to AA profile the supply of cystine and tyrosine (conditionally essential AAs), and of histidine, taurine, proline and serine could be safely increased. Not given dispensable AAs (glutamine, asparagine, citrulline and alfa amino butyric) showed a plasma level below the norm and should be added to the diet.

[Changes in the plasma amino acid profile in critically ill patients during total parenteral therapy]

The aim of this study was to evaluate the kinetics of arterial plasma amino acid profile during the first 48 h of clinical TPN in order to assess the time necessary to reach the steady-state condition during infusion. Each patient was treated with one of three different amino acid solutions yielding, in the same nitrogen intake, different intakes of individual amino acids. We found four different kinetics for the administered amino acids: an increase of plasma levels immediately after the start of the TPN with no variations during the steady period; the same trend with the steady-state obtained after 6-24 h of TPN infusion; no influence at all; a decrease of fasting plasma levels with the steady-state attained variably during the study period. Each given amino acid showed a different trend partly depending on the supply, suggesting that the steady-state was reached sooner for most amino acids, when the supply was larger. With lower intakes, plasma levels were unaffected or decreased. We conclude that in critically ill patients at least 24 h are needed to obtain stable arterial plasma amino acid concentration during TPN with adequate intakes of amino acid. Knowledge offers the possibility for a quick and accurate assessment of the adequacy of a given preparation (tailored for critically ill patients), it reduces the time span of the study and, as a consequence, the influence of varied metabolic conditions.

Basal energy production rate and substrate use in stable cirrhotic patients

The basal energy production rate was measured using indirect calorimetry in 25 stable cirrhotic patients and 10 controls of comparable age. The endogenous substrate oxidation was also calculated by measuring urinary nitrogen excretion. The energy production rate was similar in cirrhotic patients and controls. The origins of liver disease and the degree of liver damage did not seem to influence the energy production rate. On the other hand, in cirrhotic patients, as in controls, a significant correlation was present between the energy production rate and parameters of body size, such as body weight and fat-free mass. As a consequence, cirrhotic patients with poor nutritional status, with a reduced fat-free mass, showed a lower energy production rate. The measured energy production rate was compared with the resting energy expenditure estimated by formulas commonly used in healthy individuals. The good agreement found between the measured energy production rate and calculated energy expenditure suggests that these formulas may be applied to stable cirrhotic patients in clinical practice. In cirrhotic patients, the oxidation of endogenous fat is the main contributor to basal energy production rate. The fat oxidation rate does not appear to be influenced by the hormonal pattern found in the cirrhotic patients. However, a significant correlation was present between fat oxidation and plasma free fatty acid levels. This confirms that the prevalent fat use in cirrhotic patients is supported by the greater availability of fat-derived substrates.