Six-month outcome of critically ill patients given glutamine-supplemented parenteral nutrition

Tetrahydrobiopterin is an essential cofactor required for activity of nitric oxide synthases. Existing evidence suggests that, during activation of constitutive and inducible isoforms of nitric oxide synthase, tetrahydrobiopterin is needed for allosteric and redox activation of enzymatic activity. However, precise mechanisms underlying the role of tetrahydrobiopterin in regulation of nitric oxide formation is not fully understood. In cerebral and peripheral arteries, increased availability of tetrahydrobiopterin can augment production of nitric oxide. In contrast, in arteries depleted of tetrahydrobiopterin, production of nitric oxide is impaired. Proinflammatory cytokines enhance mRNA expression of the rate-limiting enzyme of tetrahydrobiopterin biosynthesis, GTP cyclohydrolase I and stimulate production of tetrahydrobiopterin. The ability of vascular tissues to synthesize tetrahydrobiopterin plays an important role in regulation of nitric oxide synthase under physiological conditions as well as during inflammation and sepsis. More recent studies concerning expression and function of recombinant nitric oxide synthases suggest that availability of tetrahydrobiopterin is important for production of nitric oxide in genetically engineered blood vessels. In this review, mechanisms regulating availability of intracellular tetrahydrobiopterin and its role in control of vascular tone under physiological and pathological conditions will be discussed.     

Randomized trial of immune-enhancing enteral nutrition in burn patients

BACKGROUND: "Immune-enhancing" diets (IEDs) are aimed at improving outcomes in patients suffering trauma and infection. This study was conducted to evaluate a popular IED in patients suffering burn injury. METHODS: Fifty burned patients were randomized to receive either Impact (Sandoz Nutrition, Minneapolis, Minn), an IED enhanced with omega-3 fatty acids, arginine, and RNA, or Replete (Clintec, Deerfield, Ill), our standard high-protein diet. Feedings were begun within 48 hours of injury, and continued until patients supported themselves with oral intake. RESULTS: Forty-nine patients completed the study. The two feeding groups did not differ with respect to age, burn size, incidence of inhalation injury, or the quantity of calories and protein received. There were no differences between groups in mortality, length of hospitalization, hospital charges, days of ventilator support, or incidence of complications. Patients with inhalation injuries required more ventilatory support, and had longer lengths of hospitalization and higher costs. CONCLUSIONS: Administration of an IED has no clear advantages over the use of less expensive high-protein enteral nutrition in burn patients.     

Nutritional support of critically ill patients

Severe depletion of body protein stores can result from prolonged starvation or from hormonal and cytokine-mediated effects during critical illness. Recent advances in the understanding of cytokine actions have substantially refined the interpretation of the nutritional assessment of critically ill patients. In addition, the design of nutritional programs for hospitalized patients has changed considerably during the past decade. Although nutritional support of critically ill patients will not lead to positive nitrogen balance, nutrition can increase protein synthesis, enhance immune function, and beneficially modify the body's response to an illness.     

Comparison of gastric mucosal pH and clinical judgement in critically ill patients

OBJECTIVES: To compare gastric tonometry (pHi) with estimates of pHi in ill injured patients, and to correlate pHi with haemodynamic variables. DESIGN: Prospective, non-interventional study. SETTING: ICU of Level I trauma centre, USA. MAIN OUTCOME MEASURES: 154 gastric tonometry measurements were compared with physicians' estimates of adequacy of resuscitation. Resuscitation was categorised as inadequate (pHi < 7.35) or adequate (pHi> or = 7.35). Measured and estimated pHi were also compared with oxygen delivery, oxygen consumption, cardiac index, mixed venous O2 saturation, and critical illness scores. RESULTS: Estimated pHi was often higher than measured pHi in the judgement of all four surgical intensive care physicians. Measured pHi correlated positively with mixed venous O2 tension (r = 0.21). There were significant negative correlations between measured pHi and both oxygen delivery (r = -0.25) and oxygen consumption (r = 0.28). Estimated pHi correlated positively with mean arterial pressure (r = 0.21) and hospital day (r = 0.26); it correlated negatively with pulmonary arterial elastance (r = -0.35). CONCLUSION: Experienced intensive care physicians tended to overestimate visceral perfusion, which suggests that gastric tonometry adds useful information over and above routine haemodynamic indices. Arterial blood pressure and mixed venous oxygen saturation correlated better with measured pHi than with other indices of perfusion.     

Does loss of body protein determine outcome in patients who are critically ill?

Gallbladder (GB) abnormalities are rarely reported in children, but involvement of the GB has been demonstrated in various inflammatory disorders. Thirty-nine children hospitalized with hepatitis A virus infection were evaluated by ultrasound. Pseudosurgical gallbladder wall of 10 mm or more with striation was found in 10. Pathological echographic findings were found in the pancreas of three patients, one with frank pancreatitis. Ascitic fluid was noted in eight. Pediatricians and pediatric surgeons alike should be familiar with this gallbladder and pancreatic involvement, which might avoid unnecessary procedures or surgery.     

Reversing oliguria in critically ill patients

Oliguria is a common occurrence in the ICU setting. In patients with preserved renal function, fluid challenges or low doses of diuretics are generally successful. In patients with oliguric renal failure, it is still essential to ensure adequate intravascular fluid volume, especially in critically ill patients. Loop diuretics remain the mainstay of treatment. When diuretic resistance is encountered, physicians should consider further optimization of hemodynamics, alternative loop diuretics, and combined drug therapy. In some cases, continuous renal replacement therapy can be very effective. Yet, while these interventions can help reduce the morbidity of severe volume overload, they have not been shown to improve mortality rates.     

Cost and outcome analysis of home parenteral and enteral nutrition

BACKGROUND: Previous estimates of the cost of home parenteral and enteral nutrition (HPEN) have excluded hospitalization costs or were conducted abroad and have limited applicability in the United States. Few studies have used validated measures to determine the effect of home nutrition support on quality of life. METHOD: A cost and clinical outcome analysis was performed by retrospective review of charts of patients receiving HPEN from 1991 to 1996. Questionnaires to determine the influence of therapy on lifestyle (n = 41) and a general health status questionnaire, the short form 36-item survey (n = 39), were mailed to patients. RESULTS: The annual cost per patient for parenteral solutions was $55,193 +/- 30,596 (mean +/- SD) based on Medicare charges and for enteral tube feedings was $9605 +/- 9327. The annual cost of hospitalization ranged from zero to $140,220 in the parenteral nutrition group and from zero to $39,204 in the enteral nutrition group. The annual number of hospitalizations per patient for patients receiving parenteral nutrition ranged from 0.52 to 1.10, compared with 0 to 0.50 in the enteral nutrition population. The health status of HPEN patients was significantly lower (p < .05) in five of the eight short-form 36 health domains compared with the general population. The areas of lifestyle most frequently affected were travel, sleep, exercise and leisure. CONCLUSIONS: The majority of the cost of therapy was associated with the direct provision of nutrition, although in some patients the hospitalization expenditure exceeded this cost. Home nutrition support had a significant negative impact on a patient's quality of life and lifestyle.     

A hermeneutic study of the experiences of relatives of critically ill patients

This paper describes a hermeneutic study of experiences of relatives of critically ill patients in the context of a large tertiary referral hospital in Sydney, Australia. The participants were 15 female family members of critically ill patients. Taped conversations between the researcher and participants were conducted and interpreted using Reinharz's hermeneutic method. Two themes emerged from the participants' experiences and are described as 'being-with' and 'seeing'. 'Being-with' focused on the desire of the participants to 'be-with' their relatives, in a physical and emotional sense. The theme 'seeing' highlighted the importance of actually seeing the patient. Ontological concepts relating to the themes are described with reference to Taylor's concept of being human.     

Human growth hormone kinetics in critically ill patients

Several studies have shown that exogenous human growth hormone (HGH) exerts an anabolic effect on protein metabolism in surgical patients with mild or moderate catabolism. However, contradictory results have been demonstrated in polytrauma patients where HGH did not improve protein metabolism. Aim of this study was to evaluate whether the pharmacokinetics of recombinant biosynthetic human GH (r-HGH) are altered in critically ill patients. After an overnight fast, r-HGH was infused at a rate of 460 micrograms/h/kg/bw during 120 min to five intensive care unit (ICU) patients. The patients were catabolic (nitrogen balance -11 +/- 0.5), showed normal liver function, and only one patient had a slightly impaired kidney function (creatinine > 1.5 mg/dl). Endogenous GH secretion was suppressed by continuous infusion of 50 micrograms/m2/h somatostatin. From plasma GH curves, elimination half life (t1/2kle), whole body clearance (Cltot) and steady state distribution space (DS) were calculated in an open two compartment model. Additionally, the effects of r-HGH infusion on plasma insulin, glucagon and amino acid concentrations were evaluated. T1/2kle was 19.6 +/- 2.3 min, Cltot 2.9 +/- 0.4 ml/kg/bw/min and DS 76.4 +/- 3.8 ml/kg/bw for 90 min. The plasma levels of total amino acids including the branched chain amino acids valine, leucine and isoleucine and of glutamine were significantly higher during r-HGH infusion than during the basal and somatostatin periods. In conclusion, the elimination of r-HGH in catabolic ICU patients is not different from that of healthy volunteers.     

ICU患者肠内营养相关性腹泻分析

目的:观察43例ICU病人肠内营养相关性腹泻的临床特点.方法:选择2009年1月-2010年1月行肠内营养并发腹泻43例患者使用的肠内营养液的量、速度,以及患者低蛋白血症、是否应用广谱抗生素的情况,将调查数据进行统计学分析,分析肠内营养并发腹泻的发生原因,提出有效的干预措施.结果:肠内营养相关性腹泻的发生与营养液供给的量和速度、病人并发低蛋白血症以及药物的使用等有关.结论:综合干预可以改善病人的低蛋白血症,降低肠内营养病人腹泻的发生率.     

Predictability of creatinine clearance estimates in critically ill patients

OBJECTIVES: a) To evaluate the predictive ability of different creatinine clearance methods as compared with the criterion standard, inulin clearance; and b) to determine which of the predictive methods yields the most accurate estimation of creatinine clearance. DESIGN: Prospective study. SETTING: Medical intensive care unit (ICU) of a university-affiliated tertiary care hospital. INTERVENTIONS: Glomerular filtration rate was measured by the criterion standard, inulin clearance. PATIENTS: Twenty mechanically ventilated adults. MEASUREMENTS: Renal function was assessed by the following procedures: inulin clearance using a standard protocol, 30-min creatinine clearance, 24-hr creatinine clearance, and creatinine clearance estimates by the Cockcroft-Gault equation. Ideal body weight, total body weight or lean body mass with actual serum creatinine or serum creatinine concentration corrected to 1 mg/dL (85 mumol/L) in cachectic patients were sequentially incorporated into the Cockcroft-Gault equation. RESULTS: The Cockcroft-Gault equation, using ideal body weight and the corrected serum creatinine concentration, was the best predictor of inulin clearance with the smallest bias (9.7 +/- 8.6, 95% confidence interval 5.7 to 13.8). The bias encountered with the 30-min creatinine clearance was not different from that value with the 24-hr creatinine clearance (21.6 +/- 33.0, 95% confidence interval 6.2 to 37.1 vs. 25.4 +/- 28.3, 95% confidence interval 11.8 to 42.9). Good correlations existed between inulin clearance and the Cockcroft-Gault equation, using ideal body weight and the corrected serum creatinine concentration (r2 = .81; p = .0001), as well as between inulin clearance and the Cockcroft-Gault equation, using the lower of ideal or total body weight and the higher of the actual serum creatinine concentration or corrected serum creatinine (r2 = .75; p = .0001). The 30-min creatinine clearance and the 24-hr creatinine clearance had poorer agreement with inulin clearance. The incorporation of a corrected serum creatinine value into the Cockcroft-Gault equation consistently led to better predictions and higher correlation coefficients. CONCLUSIONS: The utilization of the Cockcroft-Gault equation as used clinically (the lower of ideal or total body weight and the higher of actual serum creatinine or corrected serum creatinine concentration to 1 mg/dL [85 mumol/L]) results in more accurate predictions of glomerular filtration rate in the medical, critically ill patient than urine creatinine clearance measures. If creatinine clearance measures are used, the 30-min collection provided results not different from those results obtained with 24-hr urinary collections.     

Bone hyperresorption is prevalent in chronically critically ill patients

STUDY OBJECTIVE: Chronically critically ill (CCI) patients are primarily elderly people who have survived a life-threatening episode of sepsis but remain profoundly debilitated and ventilator dependent. The objective of this study was to determine the prevalence of bone hyperresorption and parathyroid hormone (PTH)-vitamin D axis abnormalities in these patients. DESIGN: Prevalence survey. SETTING: Respiratory care step-down unit (RCU) at a tertiary care teaching hospital. PATIENTS: Forty-nine ventilator-dependent CCI patients transferred from ICUs within the same institution. INTERVENTION: None. MEASUREMENTS AND RESULTS: N-telopeptide (NTx) levels in 24-h urine collections and serum intact PTH, 25-vitamin D, and 1,25-vitamin D levels were measured within 48 h of RCU admission. Patients were hospitalized a median of 30 days before RCU admission. Four patients (9%) had normal NTx and PTH levels. Forty-five patients (92%) had elevated urine NTx levels consistent with bone hyperresorption. Nineteen patients (42% of total patients) had elevated PTH levels consistent with predominant vitamin D deficiency, 4 patients (9%) had suppressed PTH levels consistent with predominant hyperresorption from immobilization, and 22 patients (49%) had normal PTH levels consistent with an overlap of both vitamin D deficiency and immobilization. There were no differences in vitamin D metabolites among these groups. CONCLUSIONS: CCI patients have a high prevalence of bone hyperresorption in which PTH levels may clarify the cause. Further studies will determine the efficacy and cost-effectiveness of routine NTx and PTH screening in these patients and the role of vitamin D and antiresorptive therapies.