A sensible approach to the nutritional support of mechanically ventilated critically ill patients

Mechanical ventilation in snake envenomation of dogs and cats

Envenomation by snakes in Elapidae and Viperidae families have been associated with respiratory failure in dogs and cats. Mechanical ventilation may be required for hypoventilation due to neuromuscular paralysis or hypoxemia due to pulmonary hemorrhage or aspiration pneumonia. Median incidence of dogs and cats with snake envenomation that require mechanical ventilation is 13% (0.06-40%). Standard treatment of snake envenomation in dogs and cats includes prompt administration of appropriate antivenom and management of envenomation complications such as coagulopathy, rhabdomyolysis and acute kidney injury. When mechanical ventilation is required, overall prognosis is good with appropriate treatment. Standard anesthetic protocols and mechanical ventilator settings are generally appropriate, with lung protective ventilation strategies typically reserved for patients with pulmonary disease. Median survival to discharge for cats and dogs with elapid envenomation is 72% (76-84%) with 33 h (19.5-58 h) median duration of mechanical ventilation and 140 h (84-196 h) median hospitalization. This article reviews indications for mechanical ventilation in cats and dogs with snake envenomation, and discusses ventilator settings, anesthetic and nursing considerations, complications and outcomes specific to this disease.

Effect of Whey Proteins on Malnutrition and Extubating Time of Critically Ill COVID-19 Patients

The novel SARS-CoV-2 virus has led to a severe pandemic, starting from early 2020. Intensive care (ICU) management of the COVID-19 disease is difficult with high morbidity and mortality. Early nutritional support, especially with whey protein, seems to be crucial in this medical case. Thus, we aimed to assess the effects of an adequate nutritional protocol rich in whey protein on nutritional and inflammatory status, extubating time, and mortality of critically ill COVID-19 patients (CICP). Methods: A prospective single-center exploratory observational study was undertaken on 32 consecutive CICP admitted to the ICU of Santa Maria Hospital, Terni, Italy, and treated with whey protein-enriched formula. Patients’ demographics, nutritional status, indexes of inflammation, daily pre-albumin serum levels, duration of mechanical ventilation, and mortality were recorded. Results: Thirty-two patients were enrolled. Ninety-five percent of them showed a gradual reduction in C-reactive protein (CRP) values and increase in pre-albumin levels after the whey protein-enriched formula. Prealbumin levels were not correlated with a better nutritional status but with a shorter extubating time and better survival. Conclusions: An adequate administration of whey protein during COVID-19 patients’ ICU stays can provide fast achievement of protein targets, reducing the duration of mechanical ventilation, and improving inflammatory status and ICU survival. Further prospective and large-scale, controlled studies are needed to confirm these results.

Pre-albumin is a strong prognostic marker in elderly intensive care unit patients

Objectives

Pre-albumin (PAB) can be used to evaluate the association between nutrition status and in-hospital mortality. However, there is no literature to compare if PAB is the best indicator to predict in-hospital mortality among the nutrition indexes in a study.

Methods

We operated a retrospective study including 145 patients admitted to our institution’s elderly intensive care unit (ICU) from January, 2017 to December, 2019. Admission laboratory results were collected. Regression analysis and receiver operating curve (ROC) were analyzed to explore the performance of different nutrition indexes.

Results

The levels of PAB were significantly different between the survivor and non-survivor group (p=0.001). Univariate analysis showed nutrition indexes (lymphocytes, albumin, body mass index [BMI], geriatric nutritional risk index (GNRI), prognostic nutritional index [PNI] and PAB) were associated with in-hospital mortality (all p<0.1). Following adjustment for age, platelets and creatinine (CREA), only BMI and PAB remained statistically significant (BMI: HR 2.799, 95% CI 1.167–6.715, p=0.021; PAB: HR 6.329, 95% CI 2.660–15.151, p<0.001). In addition, PAB had the highest area under the curve (AUC) for predicting in-hospital mortality (AUC = 0.696) followed by BMI (AUC = 0.561) and other factors.

Conclusions

PAB is a better predictor of in-hospital mortality than other nutrition indexes in elderly ICU patients.

Audit of the provision of nutritional support to mechanically ventilated dogs and cats

OBJECTIVES

To evaluate the use of enteral and parenteral nutrition in a population of mechanically ventilated cats and dogs, identify factors associated with implementation of nutrition, and assess the frequency of nutritional support within 72 hours of absent caloric intake.

DESIGN

Retrospective, single-center audit from June 2013 to June 2016.

SETTING

ICU of a veterinary university teaching hospital.

ANIMALS

Fifty-eight animals (50 dogs, 8 cats) that underwent mechanical ventilation for ≥6 hours with complete medical records.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data collected included nutritional provision, time to initiation of nutrition, period of absent caloric intake, percentage of caloric intake obtained, and possible factors contributing to the delay or failure to implement nutrition. Thirty-one percent of patients (dogs 16/50, 32%; cats 2/8, 25%) received nutritional support during mechanical ventilation with all but 2 dogs receiving parenteral nutrition. Of those patients that did not receive nutrition (dogs 34/50, 68%; cats 6/8, 75%), documented contraindications or notations within the medical record for its omission were present in 16 of 34 dogs (47%) and 4 of 6 cats (66.7%). Thirteen animals (11 dogs, 2 cats) had >72 hours of absent caloric intake with only a small number of these receiving nutrition (dogs 4/11, 36.4%; cats 0/2, 0%).

CONCLUSIONS

Only 18 of 58 (31%) mechanically ventilated dogs and cats at our institution received nutritional support, and the majority of these were fed parenterally (16/18, 88.9%). For animals that did not receive nutrition, there was no clear reason for its absence in many cases. Animals with absent caloric intake >72 hours had poor implementation of nutritional support in contrast to current guidelines. A repeat audit after implementing changes to institutional protocols for nutritional provision is warranted to assess the impact on morbidity and mortality.

Prealbumin Is Associated With In-Hospital Mortality in Critically Ill Patients

BACKGROUND

Prealbumin (PAB) has been shown to be a useful index of nutrition status in clinically stable patients. In the setting of critical illness, however, PAB is a negative acute phase reactant and may also reflect severity of illness. The purpose of this study was to evaluate the relationship between PAB and clinical outcomes in critically ill patients.

METHODS

This was a single-center, retrospective, nonrandomized cohort study of adult intensive care unit (ICU) patients. Baseline PAB and change in PAB were analyzed. The primary outcome was in-hospital mortality, and the secondary outcome was hospital length of stay (LOS). Data collected included PAB levels, Charlson Comorbidity Index, LOS, in-hospital mortality, and nutrition intake. Linear and logistic regressions were used to characterize the association between PAB levels and clinical outcomes.

RESULTS

Our study included 926 patients. Patients expiring in hospital experienced a greater decrease in PAB over time, -1.3 vs -0.7 mg/dL (odds ratio 0.94 [0.9-0.98] in multivariable regression, P = .002). Baseline PAB was not associated with in-hospital mortality or LOS. Exploratory analyses demonstrated a weak correlation between nutrition and change in PAB.

CONCLUSION

Our data demonstrate that change in PAB is associated with hospital mortality. Nutrition intake weakly correlated with change in PAB. PAB does not appear to be a robust marker of nutrition therapy but may have value as a prognostic indicator in the ICU setting.

Observed appetite and nutrient intake three months after ICU discharge

BACKGROUND & AIMS

Oral intake is diminished immediately after ICU discharge, yet factors affecting nutritional intake after hospital discharge have not been evaluated. The aim of this study was to evaluate dietary intake and factors which may influence intake - appetite and gastric emptying - 3-months after ICU discharge.

METHODS

Inception cohort study with ICU survivors compared to healthy subjects. Following an overnight fast, all participants consumed a standardized carbohydrate drink, containing ¹³C-octanoic acid, to measure gastric emptying. Dietary intake was assessed by recall of the preceding day and a standard weighed buffet meal 4-h post-drink. Appetite was assessed pre-drink (fasting) and pre- and post-buffet using visual analogue scales.

RESULTS

Fifty-one ICU survivors (82% male; 70 ± 9 y; BMI 28 ± 6 kg/m²) and 25 healthy subjects (60% male; 67 ± 12 y; BMI 27 ± 4 kg/m²) were evaluated. From the 24-h recall ICU survivors consumed less calories (ICU 1876 (708) vs. healthy subjects 2291 (834) kcal; p = 0.025) with no difference in macronutrient intake, however reported a lower preference for fat (p < 0.001). Calorie and macronutrient intake from the weighed buffet was similar between groups: calories (ICU: 658 (301) vs. healthy subjects: 736 (325) kcal; p = 0.149); protein (ICU: 37 (19) vs. healthy subjects: 40 (17) g; p = 0.275); fat (ICU: 23 (12) vs healthy subjects: 26 (13) g; p = 0.261); and carbohydrates (ICU: 69 (35) vs. healthy subjects: 79 (42) g; p = 0.141). ICU survivors reported feeling less full regardless of time-point (p = 0.041). There was no difference in the rate of gastric emptying between the two groups (p = 0.216).

CONCLUSIONS

ICU survivors reported less preference for fat and less calorie consumption than healthy subjects. However, intake of calories and macronutrients at a weighed meal was similar in the two groups, as was the rate of gastric emptying. ICU survivors reported being less full after the test meal, suggesting factors other than appetite may influence intake.

Fat-Modified Enteral Formula Improves Feeding Tolerance in Critically Ill Patients: A Multicenter, Single-Blind, Randomized Controlled Trial

BACKGROUND

Improvement of fat digestion and absorption was supposed to relieve feeding intolerance. This trial aimed to evaluate the effect of a fat-modified enteral formula on feeding tolerance in critically ill patients.

MATERIALS AND METHODS

This trial was conducted in 7 hospitals in China. In total, 144 intensive care unit (ICU) patients with estimated need of enteral nutrition (EN) for at least 5 days were randomly given fat-modified enteral formula containing medium-chain triglycerides (MCT), carnitine, and taurine (interventional feed group, n = 71) or standard enteral formula (control feed group, n = 73). EN intake, feeding intolerance (diarrhea, vomiting, gastric retention, and abdominal distension) and outcomes (mechanical ventilator-free days of 28 days, length of ICU stay, length of hospital stay, and in-hospital mortality) were collected.

RESULTS

Daily calories and protein intake were increased in the interventional feed group compared with the control feed group ( P < .01). Total incidence of feeding intolerance was 42.3% in the interventional feed group and 65.7% in the control feed group ( P < .001). Daily incidence of feeding intolerance was 11.3%, 18.3%, 14.1%, 25.4%, and 26.1% in the interventional feed group and 31.5%, 32.9%, 34.2%, 34.2%, and 30.4% in the control feed group from study days 1-5 ( P = .0083). Incidence of feeding intolerance without abdominal distention was 32.9% in the interventional feed group and 49.3% in the control feed group ( P = .047), while the incidence of abdominal distension was 26.8% in the interventional feed group and 43.8% in the control feed group ( P = .03). No significant differences existed in outcomes between the 2 groups.

CONCLUSIONS

The fat-modified enteral formula containing MCT, carnitine, and taurine may improve feeding tolerance in critically ill patients.

Nutrition therapy for critically ill and injured patients

BACKGROUND

Nutrition support has undergone significant advances in recent decades, revolutionizing the care of critically ill and injured patients. However, providing adequate and optimal nutrition therapy for such patients is very challenging: it requires careful attention and an understanding of the biology of the individual patient's disease or injury process, including insight into the consequent changes in nutrients needed.

OBJECTIVE

The objective of this article is to review the current principles and practices of providing nutrition therapy for critically ill and injured patients.

METHODS

Review of the literature and evidence-based guidelines.

RESULTS

The evidence demonstrates the need to understand the biology of nutrition therapy for critically ill and injured patients, tailored to their individual disease or injury, age, and comorbidities.

CONCLUSION

Nutrition therapy for critically ill and injured patients has become an important part of their overall care. No longer should we consider nutrition for critically ill and injured patients just as "support" but, rather, as "therapy", because it is, indeed, a key therapeutic modality.

Comparative effects on glucose absorption of intragastric and post-pyloric nutrient delivery in the critically ill

INTRODUCTION

Studies in the critically ill that evaluate intragastric and post-pyloric delivery of nutrient have yielded conflicting data. A limitation of these studies is that the influence in the route of feeding on glucose absorption and glycaemia has not been determined.

METHODS

In 68 mechanically ventilated critically ill patients, liquid nutrient (100 ml; 1 kcal/ml containing 3 g of 3-O-Methyl-D-glucopyranose (3-OMG), as a marker of glucose absorption), was infused into either the stomach (n = 24) or small intestine (n = 44) over six minutes. Blood glucose and serum 3-OMG concentrations were measured at regular intervals for 240 minutes and the area under the curves (AUCs) calculated for 'early' (AUC60) and 'overall' (AUC240) time periods. Data are presented as mean (95% confidence intervals).

RESULTS

Glucose absorption was initially more rapid following post-pyloric, when compared with intragastric, feeding (3-OMG AUC60: intragastric 7.3 (4.3, 10.2) vs. post-pyloric 12.5 (10.1, 14.8) mmol/l.min; P = 0.008); however, 'overall' glucose absorption was similar (AUC240: 49.1 (34.8, 63.5) vs. 56.6 (48.9, 64.3) mmol/l.min; P = 0.31). Post-pyloric administration of nutrients was also associated with greater increases in blood glucose concentrations in the 'early' period (AUC60: 472 (425, 519) vs. 534 (501, 569) mmol/l.min; P = 0.03), but 'overall' glycaemia was also similar (AUC240: 1,875 (1,674, 2,075) vs. 1,898 (1,755, 2,041) mmol/l.min; P = 0.85).

CONCLUSIONS

In the critically ill, glucose absorption was similar whether nutrient was administered via a gastric or post-pyloric catheter. These data may have implications for the perceived benefit of post-pyloric feeding on nutritional outcomes and warrant further investigation.

Adherence to the National Institute of Clinical Excellence guidance on parenteral nutrition screening is not enough to improve outcomes

BACKGROUND & AIM

Majority of the National Institute of Clinical Excellence (NICE) nutrition guidance recommendations were based on Grade D evidence due to absence of randomised controlled trials. The aim was to assess outcomes of parenteral nutrition (PN) administration when the guidance was adhered to.

METHODS

The prospective study included patients referred for PN. Patients were divided into two groups: guidance compliant and guidance non-compliant. Primary outcome measures were duration of PN treatment, number of PN bags used per patient, length of hospital stay and mortality.

RESULTS

There were 262 patients, aged 54(42-67) [median (IQR)] years. The guidance compliant and the non-compliant groups consisted of 143 and 119 patients respectively. In the guidance compliant group all patients were screened on admission compared to 40% in the non-compliant group (p < 0.001). Among those malnourished/at risk of malnutrition all were referred for early dietetic assessment in the compliant group but only 14% in the non-compliant group (p < 0.001). There was no difference in any of the outcome measures between the groups.

CONCLUSION

Compliance with the nutritional guidance in the UK was not enough to improve outcomes in patients requiring PN in our cohort. Evidence based changes to PN practice are required to optimise care.

A prospective randomised study comparing oral 13C-bicarbonate tracer technique versus indirect calorimetry for measurement of energy expenditure in adults

BACKGROUND AND AIMS

Accurate assessment of energy expenditure (EE) is important in guiding nutritional therapy but current methods are unsatisfactory. This study compared the oral ¹³C-bicarbonate tracer (BT) technique using the IRIS® system (Wagner, Germany) against indirect calorimetry (IC, ventilated-hood) to measure CO₂ output (VCO₂) and thus estimate EE.

METHODS

Ten overnight-fasted healthy male volunteers were randomised to studies at rest or mild exercise in a crossover manner. During each study BT-IRIS® and IC were used simultaneously to measure VCO₂ and thus EE. Participants ingested a drink labelled with 50mg ¹³C-bicarbonate and breath samples were collected every 5 min for 180 min and analysed using IRIS®. Bland-Altman plots were used to assess agreement between the two techniques in measurements of VCO₂ (L/day) and estimates of EE (kJ/day).

RESULTS

Mean ± SE age and BMI of participants were 21.1 ± 1.1 yrs and 23.6 ± 0.6 kg/m². Both at rest and exercise, there was small bias but overall poor agreement between the two techniques as evident by the wide 95% limits of agreement in measurements of VCO₂ and EE: rest VCO₂ (bias 1.4, SD 93, 95% limits of agreement -180 to 183), rest EE (-8.3, 1830, -3595 to 3578), exercise VCO₂ (49.3, 66.1, -80.4 to 178.9) and exercise EE (1083, 1944, -2727 to 4893). Furthermore, there was also evidence of systematic error in these measurements.

CONCLUSION

Prior to clinical application, further optimisation of the BT-IRIS® system should be undertaken, given the poor agreement with IC in measuring VCO₂ and estimating EE.

Influence of adherence to the national guidance on nutrition screening and dietitian referral on clinical outcomes of those requiring parenteral nutrition

BACKGROUND

National guidance in the UK on nutrition support suggests that all patients should be screened on initial admission to hospital and, where appropriate, be referred to a healthcare professional. The present study aimed to investigate whether initial nutrition screening influenced the outcome of patients who received parenteral nutrition (PN).

METHODS

Data were prospectively evaluated on 100 consecutive patients referred to the multidisciplinary PN team in a teaching hospital. Information was obtained from medical notes, electronic patient records, completed PN prescription charts, dietetic record cards and nursing care plans. Patients who were treatable by nutritional supplements or enteral nutrition were not included. Patients were divided into two groups: guidance compliant and guidance noncompliant, in order to compare outcome measures such as the duration of PN treatment, total number of PN bags used per patient and length of hospital stay. Comparison of data between the two groups was carried out using either the independent samples t-test or the Mann-Whitney U-test.

RESULTS

There was no difference in outcome measures between the guidance compliant and noncompliant groups. Patients in the guidance noncompliant group were more likely to be in general (77%) than critical wards (23%). Patients who were in the guidance compliant group received nutrition support earlier.

CONCLUSIONS

Compliance with the national guidance in the UK on screening did not improve outcomes in patients requiring parenteral nutrition in this cohort. Initial nutrition screening prior to PN administration warrants further investigation to ensure value is added to patient care.

A comparison between ventilation modes: how does activity level affect energy expenditure estimates?

BACKGROUND

An appropriate diet is essential to avoid complications of overfeeding or underfeeding in mechanically ventilated intensive care unit (ICU) patients. The paucity of consistent comparative data on energy expenditure for each ventilation mode complicates diet prescription. This study evaluates caloric requirements by comparing estimated and measured energy expenditure values for 2 ventilation modes.

METHODS

The energy expenditure of 100 ICU patients on assisted or controlled mechanical ventilation was measured by indirect calorimetry for 20 minutes. Values were calculated for a 24-hour period and compared with Harris-Benedict estimates multiplied by an injury factor and either multiplied or not by a 10% activity factor.

RESULTS

The mean Harris-Benedict estimate was 1858.87 +/- 488.67 kcal/24 h when multiplied by an injury factor and a 10% activity factor. The mean energy expenditure values measured by indirect calorimetry were 1712.76 +/- 491.95 kcal/24 h for controlled and 1867.33 +/- 542.67 kcal/24 h for assisted ventilation. The mean total energy expenditure for assisted ventilation was 10.71% greater than the mean for controlled ventilation (P < .001). For controlled ventilation, Harris-Benedict results overestimated indirect calorimetry values by 141.10 +/- 10 kcal/24 h (8.2%, P = .012) when multiplied by injury and activity factors, and underestimated values by 44.28 +/- 28 kcal/24 h (2.6%, P = .399) when the equation was calculated without the activity factor. For assisted ventilation, Harris-Benedict results underestimated indirect calorimetry values by 198.84 +/- 84 kcal/24 h (10.7%, P = .001) when not multiplied by the activity factor and by 13.46 kcal/24 h (0.75%) when the activity factor was used, but differences were not statistically significant (P = .829).

CONCLUSIONS

Results suggest that a 10% activity factor should be adopted only for assisted ventilation because multiplication by an activity factor may lead to overfeeding of patients on controlled ventilation.

The effects of sedation on gastric emptying and intra-gastric meal distribution in critical illness

OBJECTIVE

To evaluate the effects of sedation with morphine and midazolam (M&M) versus propofol on gastric emptying in critically ill patients.

DESIGN

Descriptive study.

SETTING

Mixed medical and surgical intensive care unit.

PATIENTS

Thirty-six unselected, mechanically ventilated, critically ill patients.

INTERVENTIONS

Gastric scintigraphic data were analysed retrospectively according to whether patients were receiving M&M (n=20; 14M, 6F) or propofol (n=16; 7M, 9F). Measurements were performed over 4 h after administration of 100 ml of Ensure, labelled with 20 MBq Tc99m.

MEASUREMENTS AND RESULTS

Gastric half-emptying time (t1/2) and total and regional (proximal and distal stomach) meal retention (%) were assessed. The median t1/2 of patients receiving M&M (153 (IQR: 72-434) min) was significantly longer than that of patients receiving propofol (58 (34-166) min, p=0.02). Total gastric retention was greater in patients receiving M&M compared to those receiving propofol (p<0.01). Proximal (p=0.02) but not distal (p=0.80) gastric retention was greater in patients who received M&M. Patients who received M&M were more likely to have >or=5% meal retention at 240 min than those treated with propofol (95% (19/20) vs. 56% (9/16); p=0.01). Changes in blood glucose concentrations during the study were similar in the two groups.

CONCLUSIONS

In critical illness, patients receiving M&M for sedation are more likely to have slow gastric emptying, and proximal meal retention than those receiving propofol. The apparent beneficial effects of propofol-based sedation need confirmation by a prospective randomised controlled study.

Standardized concept for the treatment of gastrointestinal dysmotility in critically ill patients--current status and future options

Inhibition of gastrointestinal motility is a major problem in critically ill patients. Motor stasis gives rise to subsequent complications including intolerance to enteral feeding, enhanced permeability of the atrophic intestinal mucosa and conditions as severe as systemic inflammatory response syndrome, sepsis and multiple organ failure. Although the diagnosis of motility disturbances in critically ill patients is difficult, the type and site of the disturbance are important to consider in the analysis of the condition and in the choice of therapeutic approach. The pharmacological treatment of impaired gastrointestinal motility is difficult to handle for the clinician, because the underlying mechanisms are complex and not fully understood and the availability of pharmacological treatment options is limited. In addition, there is a lack of controlled studies on which to build an evidence-based treatment concept for critically ill patients. Notwithstanding this situation, there has been remarkable progress in the understanding of the integrated regulation of gastrointestinal motility in health and disease. These advances, which largely relate to the organization of the enteric nervous system and its signaling mechanisms, enable the intensivist to develop a standardized concept for the use of prokinetic agents in the treatment of impaired gastrointestinal motility in critically ill patients.

24-hour indirect calorimetry in mechanically ventilated critically ill patients

BACKGROUND

Energy imbalance in critically ill, mechanically ventilated patients may lead to medical complications. The nutrition care team needs accurate, noninvasive, rapid methods to estimate energy requirements. We investigated whether brief measurements of indirect calorimetry at any time of the day would give valid estimates of 24-hour energy expenditure (EE).

METHODS

EE of 12 mechanically ventilated critically ill patients (6 men, 6 women, mean +/- SD age 67 +/- 18 years, weight 70.2 +/- 8.8 kg) was recorded every minute during 24 hours by indirect calorimetry. All patients were continuously fed enteral nutrition.

RESULTS

Mean +/- SD EE was 1658 +/- 279 kcal/d (6941 +/- 1167 kJ/d). Within patients, EE during the day fluctuated by 234 kcal in the most constant patient to 1190 kcal in the least constant patient, with a mean fluctuation of 521 kcal (12 patients). No statistically significant difference (p = .53) in mean EE between morning (6-12 hours, 1676 kcal), afternoon (12-18 hours, 1642 kcal), evening (18-24 hours, 1658 kcal), and night (0-6 hours, 1655 kcal) was found. A 2-hour instead of a 24-hour measurement resulted in a maximal error of 128 kcal (536 kJ), which was <10% of the average EE. The maximal error decreased with longer time intervals.

CONCLUSIONS

In mechanically ventilated critically ill patients, 24-hour indirect calorimetry measurements can be replaced by shorter (>/=2 hours) measurements. Time of day did not affect EE.

Evaluation of a technique for blind placement of post-pyloric feeding tubes in intensive care: application in patients with gastric ileus

OBJECTIVE

To evaluate a blind 'active' technique for the bedside placement of post-pyloric enteral feeding tubes in a critically ill population with proven gastric ileus.

DESIGN AND SETTING

An open study to evaluate the success rate and duration of the technique in cardiothoracic and general intensive care units of a tertiary referral hospital.

PATIENTS

20 consecutive, ventilated patients requiring enteral nutrition, where feeding had failed via the gastric route.

INTERVENTIONS

Previously described insertion technique-the Corpak 10-10-10 protocol-for post-pyloric enteral feeding tube placement, modified after 20 min if placement had not been achieved, by insufflation of air into the stomach to promote pyloric opening.

MEASUREMENTS AND RESULTS

A standard protocol and a set method to identify final tube position were used in each case. In 90% (18/20) of cases tubes were placed on the first attempt, with an additional tube being successfully placed on the second attempt. The median time for tube placement was 18 min (range 3-55 min). In 20% (4/20) insufflation of air was required to aid trans-pyloric passage.

CONCLUSIONS

The previously described technique, modified by insufflation of air into the stomach in prolonged attempts to achieve trans-pyloric passage, proved to be an effective and cost efficient method to place post-pyloric enteral feeding tubes. This technique, even in the presence of gastric ileus, could be incorporated by all critical care facilities, without the need for any additional equipment or costs. This approach avoids the costs of additional equipment, time-delays and necessity to transfer the patient from the ICU for the more traditional techniques of endoscopy and radiographic screening.

Implementing clinical guidelines for nutrition in a neurosurgical intensive care unit

Patients in neurosurgical intensive care have individual needs concerning nutrition because of their conditions. An important therapeutic goal is to prevent the development of malnutrition as it contributes to an increase in mortality and enhances the risk of complications in these patients. The health-care team has a mutual responsibility for this, although it is a complex task and a correct assessment of patients' nutritional needs is vital. Multidisciplinary clinical guidelines focused on nutrition might help the health-care staff in decision-making and allowing individualized treatment for patients. The aim of this study was to evaluate the implementation and use of such a guideline. The results show that the guideline is used in varying degrees by the health-care team. Areas that focused on more practical aspects of nutritional support seemed to have a unified approach, whereas areas on nutritional assessment and routine nutrition orders demonstrated both a lack of knowledge and unclear role responsibilities. The results reveal how different professional groups in health care perceive the implementation of a clinical guideline. Some areas need further clarification, there needs to be continuing development of nutritional guidelines, and education of staff is needed in order to enhance the nutritional care of patients.

Predicted vs measured energy expenditure in critically ill, underweight patients

A retrospective analysis was conducted to compare 4 energy-prediction equations against measured resting energy expenditure (MREE) determined via indirect calorimetry. Data from a heterogeneous group of 42 critically ill, severely underweight (59.50 +/- 17.30 kg; 77.1 +/- 9.7% ideal body weight [IBW]) male patients were assessed. The Hamwi formula was used to determine IBW. The Harris-Benedict (HB) equation was calculated for patients <90% IBW using both current body weight (CBW) and IBW. Energy needs were also estimated with an Ireton-Jones formula for all mechanically ventilated patients (n = 37). For patients <85% IBW (n = 31), an adjusted body weight was determined ([CBW + IBW]/2) and used in the HB formula. The HB formula using the IBW, CBW, and adjusted body weight was significantly different (p < .05) than MREE. The Ireton-Jones equation was not significantly different (p > .05) from MREE but tended to overestimate energy needs (109.3% +/- 16.8% MREE). Conversely, using the CBW or IBW in the HB underestimated the patient's energy needs; 77.0% +/- 11.6% MREE and 90.9 +/- 16.1% MREE, respectively. For patients <85% IBW, use of the adjusted body weight in the HB represented 84.2% +/- 13.9% MREE. The average caloric need was 31.2 +/- 6.0 kcal/kg CBW. Indirect calorimetry remains the best method of determining a patient's energy needs. Until a large prospective trial is conducted, a combination of prediction equations tempered with clinical judgment and monitoring the appropriateness of the nutrition prescription remains the best approach to quality patient care.

Estimation of energy requirements for mechanically ventilated, critically ill patients using nutritional status

BACKGROUND

There is very little information on what is considered an adequate energy intake for mechanically ventilated, critically ill patients. The purpose of the present study was to determine this energy requirement by making use of patients' nutritional status.

METHODS

The study was conducted in a multidisciplinary intensive care unit of Taichung Veterans General Hospital, Taiwan. Patients were hemodynamically stable and not comatose, and were requiring at least 7 days of mechanical ventilation. Fifty-four patients successfully completed this study. The resting energy expenditure was measured using indirect calorimetry. The total energy requirement was considered 120% of the measured energy expenditure. The daily nutrient intake was recorded. Nutritional status was assessed using single and multiple parameters, nitrogen balance, and medical records, and was performed within 24 hours of admission and after 7 days in the intensive care unit.

RESULTS

Fifteen patients were being underfed (<90% of total energy requirement), 20 patients were in the appropriate feeding (AF) group (within +/- 10% of total energy requirement), and 19 patients received overfeeding (>110% of total energy requirement). Patients in the underfeeding group received only 68.3% of their energy requirement, while the overfeeding group patients received up to 136.5% of their required calories. Only patients in the AF group had a positive nitrogen balance (0.04 +/- 5.1) on day 7. AF group patients had a significantly higher Nutritional Risk Index value at day 7 than at day 1.

CONCLUSION

AF patients had more improvement in nutritional status than patients in the other feeding groups. To provide at least 120% of the resting energy expenditure seemed adequate to meet the caloric energy needs of hemodynamically stable, mechanically ventilated, critically ill patients.

Vitamin B6 intakes and status of mechanically ventilated critically ill patients in Taiwan

OBJECTIVE

To assess vitamin B6 intake and status of critically ill patients. The relationship between vitamin B6 status indicators and the severity of illness and outcome in these patients was also examined.

DESIGN

Prospective clinical study.

SETTING

The study was performed at the Taichung Veteran General Hospital, in the central part of Taiwan.

SUBJECTS

Ninety-four patients in the intensive care unit (ICU) entered the study and 46 patients successfully completed this study.

INTERVENTIONS

No intervention.

MAIN OUTCOME MEASURES

Vitamin B6 intake was recorded for 14 days. Vitamin B6 status was assessed by direct measures (plasma pyridoxal 5'-phosphate (PLP), pyridoxal (PL), and urinary 4-pyridoxic acid (4-PA)) and indirect measures (erythrocyte alanine (EALT-AC) and aspartate (EAST-AC) aminotransaminase activity coefficient). The severity of illness (APACHE II score), the length of ventilation dependency, and the length of ICU and hospital stay were recorded.

RESULTS

Patients had an adequate mean vitamin B6 intake (16.26+/-19.39 mg) during the 14 day study. Mean vitamin B6 intake was significantly higher on day 14 than on day 1 (P<0.001). However, plasma PLP and PL concentrations significantly decreased at the 14th day after admission (P<0.05). Erythrocyte alanine aminotransaminase activity coefficient and EAST-AC did not change significantly. Urinary 4-PA significantly increased at the 14th day (P<0.001). No significant relationships were found between APACHE II scores and clinical outcomes (the length of ICU and hospital stay, the length of ventilation dependency) of patients, vitamin B6 intake or status indicators.

CONCLUSIONS

Critically ill patients received nutritional support in the ICU, and had sufficient mean vitamin B6 intake and adequate vitamin B6 status. Therefore, the severity of illness and the results should not be affected by vitamin B6 status. However, we have noted that plasma PLP and PL concentrations significantly decreased while vitamin B6 intake significantly increased on day 14. Critical clinical conditions and complex metabolism in the critically ill may account for the reduction of plasma PLP and PL. Since vitamin B6 deficiency causes profound effects on immune system function, dietary or supplemented vitamin B6 intake is suggested for hospitalized patients.

Measured versus estimated energy expenditure in mechanically ventilated critically ill patients

Accurate determination of energy expenditure is essential in patients receiving nutritional support to meet metabolic needs. The purpose of this study was to assess and compare the energy expenditure as measured by indirect calorimetry (MEE) and estimated by 5 equations in the mechanically ventilated critically ill patients. Forty-six patients were divided into either enteral nutrition (EN) (n=l2), total parenteral nutrition (TPN) (n=16) or combined (EN plus TPN) (n=l8) groups. Patients' energy expenditure was measured by indirect calorimetry on two occasions. Anthropometric and biochemical measurements, energy expenditure and medical status (APACHE II score) were also assessed in the intensive care unit (ICU) of Taichung Veteran General hospital. No significant difference was found in the MEE among the 3 groups. The type of nutritional support did not affect MEE. Energy expenditure calculated by using Harris- Benedict, Kleiber and Liu equations times the estimated stress factor did not significantly different than the values of MEE in all groups. There were significant correlations (P<0.01) between MEE and patients' sex (r=-0.499), age (r=-0.402), height (r=0.533), knee height (r=0.431), current body weight (r=0.379), usual body weight (r=0.407), ideal body weight (r=0.466) and urinary urea nitrogen (r=0.383) in the pooled group. Results demonstrated that energy expenditure could be estimated in most critically ill patients by using Harris-Benedict, Kleiber and Liu equations if the estimated stress factor is in the reasonable value.

Delayed gastric emptying in ventilated critically ill patients: measurement by 13 C-octanoic acid breath test

OBJECTIVE

To measure gastric emptying in ventilated critically ill patients with a new noninvasive breath test.

DESIGN

Single-center, open study.

SETTING

Combined medical and surgical intensive care unit of a university hospital.

SUBJECTS

Thirty unselected mechanically ventilated critically ill patients receiving gastric feeding and 22 healthy volunteers.

INTERVENTIONS

None.

PATIENTS

After 4 hrs without feeding, intragastric infusion of 100 mL of a liquid meal (Ensure) labeled with 100 microL 13C-octanoic acid. End-expiratory breath samples were collected into evacuated tubes from the respirator circuit every 5 mins for the first hour, then every 15 mins for 3 hrs. End-expiratory breath samples were also collected from volunteers studied supine after an overnight fast following an identical infusion via a nasogastric tube. Breath 13CO2 was measured with an isotope ratio mass spectrometer.

MEASUREMENTS AND MAIN RESULTS

Performance of the breath test posed no difficulty or interference with patient care. The CO2 level was >1% in 1297/1300 breath samples, indicating satisfactory end-expiratory timing. Data are median and interquartile range. Gastric emptying was slower in patients compared with volunteers: gastric emptying coefficient 2.93 (2.17-3.39) vs. 3.58 (3.18-3.79), p <.001 and gastric half emptying time, derived from the area under the 13CO2 curve, 155 min (130-220) vs. 133 min (120-145), p <.008. Fourteen of the 30 patients had a gastric emptying coefficient <95% of all volunteers and 11 had a gastric half emptying time longer than 95% of all volunteers. The Acute Physiology and Chronic Health Evaluation (APACHE II) score (median 22, range 13-43) either at admission or on the day of the study did not correlate with gastric emptying coefficient.

CONCLUSION

Gastric emptying of a calorie-dense liquid meal is slow in 40% to 45% of unselected mechanically ventilated patients in a combined medical and surgical intensive care unit. The 13C-octanoic acid breath test is a novel and useful bedside technique to measure gastric emptying in these patients.

Nutritional awareness of critically ill surgical high-dependency patients

It has been recognized that malnutrition in hospital is a serious problem that may go undetected. There is growing evidence that early nutritional support in high-risk patients helps reduce postoperative complications; however, malnutrition is often diagnosed only once it is well established. This study showed that, both retrospectively and prospectively; there were no formal nutritional assessments of patients in a high-dependency unit (HDU), that time to feeding was generally within the recommended 5-7 day postoperative period, and that the most common form of supplementary feeding was total parenteral nutrition (TPN). Prospectively, the choice of supplementary feeding was dependent on the type of surgery and the individual patient's condition. Since this study was completed, a dietician has been allocated to the HDU and carries out formal nutritional assessments on a daily basis. Further research is required to assess the impact of the dietician on patient nutrition.

Impacts and patterns of disturbed gastrointestinal function in critically ill patients

Disordered upper gastrointestinal tract motility occurs frequently in intensive care unit patients and often represents a substantial treatment challenge. In addition to specific complications such as pulmonary aspiration and diarrhea, abnormal gastrointestinal motility is a limiting factor for delivery and success of enteral nutrition. The pathophysiologies involved are incompletely understood because of the difficulties of making measurements of gastrointestinal function in critically ill patients. With the recent development of techniques that overcome some of these difficulties, the prospects are brighter for significant advances in this field.

Malnutrition in critically ill patients in intensive care units

The provision of artificial nutrition for critically ill patients is of great importance as many are unable to maintain their own nutritional needs. The administration of total parenteral nutrition (TPN) and enteral nutrition (EN) has become a daily practice in intensive care units. Despite this, many patients remain undernourished or even malnourished and it is estimated that the incidence of malnutrition in intensive care patients could be as high as 50% (McCain, 1993). The reasons by which patients become or remain undernourished are multifactorial and range from physiological to iatrogenic. In order to lessen the catabolic state which results from the hypermetabolism associated with critical illness, prompt and adequate nutritional support must be delivered. It is essential that members of the multidisciplinary team caring for critically ill patients are aware of the importance of nutrition and the deleterious effects of malnutrition to achieve the best possible outcome for patients.

Nutritional status of mechanically ventilated critically ill patients: comparison of different types of nutritional support

Malnutrition is a common problem in hospitalized patients. Early assessment of nutritional status may help in identifying patients for whom nutritional interventions are needed. The purpose of this study was to assess and compare the nutritional status of mechanically ventilated critically ill patients who were receiving nutritional support. Forty-nine patients were divided into either enteral nutrition, total parenteral nutrition or combined (enteral plus total parenteral nutrition) groups. Anthropometric and biochemical measurements, and medical status (APACHE II score) were assessed at the 1st day and 14th day of admission in the intensive care unit (ICU) of Taichung Veteran General Hospital. The length of ventilator dependency was significantly positively correlated with calorie and carbohydrate intake in the pooled group. Patients receiving enteral and combined nutrition showed significantly lower anthropometric measurements at the 14th day after admission. Patients in all groups had abnormal mean biochemical values at the 1st day of admission. Subjects in the combined group showed a significant increase in prealbumin and the Maastricht Index levels after 14 days. Patients in all three groups were malnourished when admitted to the ICU. Patients showed a slightly improvement of nutritional status after receiving nutritional support for 14 days.

Duodenal versus gastric feeding in ventilated blunt trauma patients: a randomized controlled trial

OBJECTIVE

To evaluate transpyloric feeds as they have been proposed as a means of providing enteric nutrition more rapidly and minimizing morbidity in ventilated trauma patients.

METHODS

Between July of 1994 and June of 1997, 80 adult ventilated trauma patients were enrolled in a randomized controlled trial of duodenal versus gastric feeds. Feeding was initiated within 72 hours of injury.

RESULTS

Forty-three patients received gastric feeds (G), and 37 patients received duodenal feeds (D). Mean age was 34.7+/-15.7 years (G) and 33.6+/-17.5 years (D); the difference in age was not significant (NS). Mean Injury Severity Score was 30.0+/-11 (G), 33.0+/-9.7 (D), NS. Mean Acute Physiology and Chronic Health Evaluation (APACHE II) score was 18.0+/-6.0 (G) and 18.0+/-7.4 (D), NS. Thirty-four of 43 patients were men (G) and 28 of 37 patients were men (D), NS. Use of narcotics and paralytics between the two groups was not significantly different. Energy requirements were 1.4 times basal energy expenditure at 2,127+/-304 Kcal (G) and 2,089+/-274 Kcal (D), NS. Intensive care unit length of stay was a median of 7 days (range, 3-32 days) (G) and 10 days (range, 3-24 days) (D), NS. Number of days on ventilator was a median of 5 days (range, 3-15 days) (G) and 9 days (range, 2-13 days) (D), NS. Hospital length of stay was a median of 25 days (range, 9-88 days) (G) and 30 days (range, 16-47 days) (D), NS. Recorded morbidity was not significantly different. Pneumonia rates were 42% (G) and 27% (D), NS. Time to tolerate full-strength feeds for 24 consecutive hours was 43.8 hours +/-22.6 (G) and 34.3 hours +/-7.1 (D), difference significant at p = 0.02.

CONCLUSION

Length of stay and ventilator days were not significantly different. A larger trial would be required to determine differences in the rates of pneumonia <20%. Transpyloric-duodenal feeds significantly reduce the time required to achieve targeted enteric nutrition.

Nutritional support in advanced pulmonary disease

Advanced pulmonary disease (APD), often secondary to emphysema or chronic bronchitis, is generally a progressive, incurable condition, ultimately leading to death. The condition is associated with significant, distressing symptoms. Most APD patients are underweight, which has numerous implications including accentuation of reduced physical capacity during daily life, increased risk of other secondary diseases, e.g. infections and osteoporosis, and a higher mortality during exacerbations with acute respiratory failure. Consequently, careful nutritional support is crucial both in enhancing physical well-being and function, and in reducing the risk of acute respiratory failure. Knowledge concerning the exact nutritional needs in APD is still very sparse; however, specific actions against malnutrition in APD patients should be mandatory in the treatment of APD. This paper reviews the literature concerning implications of malnutrition and benefits of nutritional support in APD patients, and gives suggestions for the practical, daily-life nutritional management of APD.

Nutrition and its importance to intensive care patients

The purpose in this paper is to consider the importance of early nutrition for critically ill patients, briefly reviewing the effects of malnutrition, and the metabolic response to starvation and sepsis. Discussion includes assessment of nutritional status and nutritional requirements, with a suggested enteral feeding regime; and also the combined effect of enteral nutrition and glutamine on gut integrity and its relevance to nosocomial pneumonia, and the ability of the gut to accept food during critical illness.

Gastric emptying following brain injury: effects of choice of sedation and intracranial pressure

OBJECTIVE

To compare the effects of opioid and non-opioid sedation on gastric emptying.

DESIGN

Prospective, randomized trial.

SETTING

University teaching hospital ICU.

PATIENTS

21 brain injured patients requiring sedation, mechanical ventilation and intracranial pressure (ICP) monitoring for > 24 h.

INTERVENTIONS

Patients were randomized to receive infusions of either morphine plus midazolam (M), or propofol (P). Gastric emptying was assessed by the paracetamol absorption technique and by residual volumes following a 200 ml test feed.

MEASUREMENTS AND RESULTS

Pre-sedation Glasgow Coma Score, mean ICP and the presence of bowel sounds were noted. Plasma concentrations of paracetamol were measured over 3 h following a 1 g gastric dose. There were no differences in median peak paracetamol concentration (M, 18.5 versus P, 20.8 mg/l), median time to peak concentration (M, 20 versus P, 25 min), median area under the concentration-time curve (AUC), or in the median residual volumes at 1 h (M, 14 versus P, 10.5 ml) and 2 h (M, 5 versus P, 3 ml). In patients with ICP > 20 mmHg, paracetamol concentrations were lower (p < 0.05), and AUC after 30 min was lower (165 mg.min/l versus 411 mg.min/l, p = 0.023). Mean ICP was correlated with AUC (Kendall rank p = 0.027). Gastric emptying did not correlate with initial Glasgow Coma Score or presence of bowel sounds.

CONCLUSIONS

Gastric emptying is not improved in patients with brain injury by avoiding morphine (1-8 mg/h) in the sedative regimen. Intracranial hypertension is associated with reduced gastric emptying.

Effects of chemically defined structured lipid emulsions on reticuloendothelial system function and morphology of liver and lung in a continuous low-dose endotoxin rat model

BACKGROUND

This study was undertaken to determine the effect of chemically defined structured lipids on nonspecific host defense and on histologic patterns of liver and lungs compared with a physical mixture of long-chain triglycerides and medium-chain triglycerides in a continuous low-dose endotoxin rat model.

METHODS

Forty male Sprague-Dawley rats, divided into four feeding groups (structured lipids, structured lipids+endotoxin, physical mixture, physical mixture+endotoxin), received total parenteral nutrition for 48 hours. During the first part of the study, 24 animals were given an injection of live Escherichia coli labeled with radioactive iron (59Fe) to investigate the function of the reticuloendothelial system. During the second part of the study, the liver and lungs of 16 animals were histologically examined using light and electron microscopy.

RESULTS

Despite the similar values in the control groups, the animals receiving structured lipids+endotoxin sequestered a significantly greater percentage of bacteria in the liver and spleen (p < or = .01) and a significantly lesser percentage in the lung (p < or = .05) compared with the animals given physical mixture+endotoxin as part of their diet. Moreover, rats in the physical mixture+endotoxin group showed a microscopically evaluated higher fatty infiltration in the liver than did the structured lipids+endotoxin group.

CONCLUSIONS

The results of this study indicate that chemically defined structured lipids reduce fatty infiltration of the liver compared with a physical mixture of the same compounds in an animal model of metabolic stress. They were accompanied by a better function of the reticuloendothelial system and a lesser bacterial sequestration in the lungs.