Quantitative analysis of the relationship between sedation and resting energy expenditure in postoperative patients

Management of Respiratory Failure in Hemorrhagic Shock

Hemorrhagic shock results in acute respiratory failure due to respiratory muscle fatigue and inadequate pulmonary blood flow. Because positive pressure ventilation can reduce venous return and cardiac output, clinicians should use the minimum possible mean airway pressure during assisted or mechanical ventilation, particularly during episodes of severe hypovolemia. Hypoperfusion also worsens dead space fraction. Therefore, clinicians should monitor capnography during mechanical ventilation and recognize that hypercapnia may be treated with fluid resuscitation rather than increasing minute ventilation.

Changes in oxygen supply-demand balance during induction of general anesthesia: an exploratory study using remimazolam

PURPOSE

This study was performed to evaluate the changes in oxygen supply-demand balance during induction of general anesthesia using an indirect calorimeter capable of measuring oxygen consumption (VO2) and carbon dioxide production (VCO2).

METHODS

This study included patients scheduled for surgery in whom remimazolam was administered as a general anesthetic. VO2 and VCO2 were measured at different intervals: upon awakening (T1), 15 min after tracheal intubation (T2), and 1 h after T2 (T3). Oxygen delivery (DO2) was calculated simultaneously with these measurements. VO2 was ascertained using an indirect calorimeter and further calculated using vital signs, among other factors. DO2 was derived from cardiac output and arterial blood gas analysis performed with an arterial pressure-based cardiac output measurement system.

RESULTS

VO2, VCO2, and DO2 decreased significantly from T1 to T2 and T3 [VO2/body surface area (BSA) (ml/min/m2): T1, 130 (122-146); T2, 107 (83-139); T3, 97 (93-121); p = 0.011], [VCO2/BSA (ml/min/m2): T1, 115 (105-129); T2, 90 (71-107); T3, 81 (69-101); p = 0.011], [DO2/BSA (ml/min/m2): T1, 467 (395-582); T2, 347 (286-392); T3, 382 (238-414); p = 0.0020]. Among the study subjects, a subset exhibited minimal reduction in VCO2. Although the respiratory frequency was titrated on the basis of end-tidal CO2 levels, there was no significant difference between the groups.

CONCLUSION

General anesthetic induction with remimazolam decreased VO2, VCO2, and DO2.

Comparative characteristics of some methods for estimating energy expenditure in critically ill mechanically ventilated patients

AIM

To compare the energy expenditure (EE) assessed by ventilator-derived carbon dioxide production (EE-VCO2-ventilator) and the energy expenditure calculated from six predictive equations with the gold standard energy expenditure measured with indirect calorimetry (IC) in mechanically ventilated patients.

The Good, the Bad, and the Serum Creatinine: Exploring the Effect of Muscle Mass and Nutrition

Muscle wasting (sarcopenia) is one of the hallmarks of critical illness. Patients admitted to intensive care unit develop sarcopenia through increased protein catabolism, a decrease in protein syntheses, or both. Among the factors known to promote wasting are chronic inflammation and cytokine imbalance, insulin resistance, hypermetabolism, and malnutrition. Moreover, muscle wasting, known to develop in chronic kidney disease patients, is a harmful consequence of numerous complications associated with deteriorated renal function. Plenty of published data suggest that serum creatinine (SCr) reflects increased kidney damage and is also related to body weight. Based on the concept that urea and creatinine are nitrogenous end products of metabolism, the urea:creatinine ratio (UCR) could be applied but with limited clinical usability in case of kidney damage, hypovolemia, excessive, or protein intake, where UCR can be high and independent of catabolism. Recent data suggest that the sarcopenia index should be considered an alternative to serum creatinine. It is more reliable in estimating muscle mass than SCr. However, the optimal biomarker of catabolism is still an unresolved issue. The SCr is not a promising biomarker for renal function and muscle mass based on the influence of several factors. The present review highlights recent findings on the limits of SCr as a surrogate marker of renal function and the assessment modalities of nutritional status and muscle mass measurements.

Associations of systemic oxygen consumption with age and body temperature under general anesthesia: retrospective cohort study

BACKGROUND

Body temperature (BT) is thought to have associations with oxygen consumption (VO2). However, there have been few studies in which the association between systemic VO2 and BT in humans was investigated in a wide range of BTs. The aims of this study were 1) to determine the association between VO2 and age and 2) to determine the association between VO2 and BT.

METHODS

This study was a retrospective study of patients who underwent surgery under general anesthesia at a tertiary teaching hospital. VO2 was measured by the Dräger Perseus A500 anesthesia workstation (Dräger Medical, Lubeck, Germany). The associations of VO2 with age and BT were examined using spline regression and multivariable regression analysis with a random effect.

RESULTS

A total of 7,567 cases were included in this study. A linear spline with one knot shows that VO2 was reduced by 2.1 ml/kg/min with one year of age (p < 0.001) among patients less than 18 years of age and that there was no significant change in VO2 among patients 18 years of age or older (estimate: 0.014 ml/kg/min, p = 0.08). VO2 in all bands of BT < 36.0 °C was not significantly different from VO2 in BT >  = 36 °C and < 36.5 °C. Multivariable linear regression analysis showed that compared with VO2 in BT >  = 36 °C and < 36.5 °C as a reference, VO2 levels were significantly higher by 0.57 ml/kg/min in BT >  = 36.5 °C and < 37 °C (p < 0.001), by 1.8 ml/kg/min in BT >  = 37 °C and < 37.5 °C (p < 0.001), by 3.6 ml/kg/min in BT >  = 37.5 °C and < 38 °C (p < 0.001), by 4.9 ml/kg/min in BT >  = 38 °C and < 38.5 °C (p < 0.001), and by 5.7 ml/kg/min in BT >  = 38.5 °C (p < 0.001). The associations between VO2 and BT were significantly different among categorized age groups (p = 0.03).

CONCLUSIONS

VO2 increases in parallel with increase in body temperature in a hyperthermic state but remains constant in a hypothermic state. Neonates and infants, who have high VO2, may have a large systemic organ response in VO2 to change in BT.

Application of Neuromuscular Blockers in Patients with ARDS in ICU: A Retrospective Study Based on the MIMIC-III Database

BACKGROUND

Although neuromuscular blocker agents (NMBAs) are recommended by guidelines as a treatment for ARDS patients, the efficacy of NMBAs is still controversial. Our study aimed to investigate the association between cisatracurium infusion and the medium- and long-term outcomes of critically ill patients with moderate and severe ARDS.

METHODS

We performed a single-center, retrospective study of 485 critically ill adult patients with ARDS based on the Medical Information Mart for Intensive Care III (MIMIC-III) database. Propensity score matching (PSM) was used to match patients receiving NMBA administration with those not receiving NMBAs. The Cox proportional hazards model, Kaplan-Meier method, and subgroup analysis were used to evaluate the relationship between NMBA therapy and 28-day mortality.

RESULTS

A total of 485 moderate and severe patients with ARDS were reviewed and 86 pairs of patients were matched after PSM. NMBAs were not associated with reduced 28-day mortality (hazard ratio (HR) 1.44; 95% CI: 0.85~2.46; p = 0.20), 90-day mortality (HR = 1.49; 95% CI: 0.92~2.41; p = 0.10), 1-year mortality (HR = 1.34; 95% CI: 0.86~2.09; p = 0.20), or hospital mortality (HR = 1.34; 95% CI: 0.81~2.24; p = 0.30). However, NMBAs were associated with a prolonged duration of ventilation and the length of ICU stay.

CONCLUSIONS

NMBAs were not associated with improved medium- and long-term survival and may result in some adverse clinical outcomes.

Changes in Physiological Indices Before and After Nursing Care of Postoperative Patients With Esophageal Cancer in the ICU

Introduction

Various stressors have been identified in patients in the intensive care unit (ICU), including postoperative pain, ventilatory management, and nursing care. However, sedated patients are less responsive, and nurses have difficulty capturing their stressors.

Objective

To investigate patient stress caused by nursing care performed in the ICU on sedated patients based on changes in physiological indices.

Methods

We observed nursing care performed on patients with postoperative esophageal cancer under sedation in the ICU. This included endotracheal suctioning and turning, the time required for the care, and the patients' behavioral responses. Information on arousal levels, autonomic nervous system indices, and vital signs were also obtained. The changes in indicators before and after care were then compared and analyzed.

Results

There were 14 patients in the study. The mean age of the patients was 68 years. Ninety-nine scenes of nursing care were observed, and in six of these, additional bolus sedation was administered because of the patient's significant body movements. In endotracheal suctioning, no significant changes were observed in all indicators. In turning, vital signs changed significantly, and when both were continued, all indicators changed significantly.

Conclusion

Our study found that different types and combinations of nursing care may cause different stresses to the patients. Moreover, the autonomic nervous system indices may be more likely to react to stresses in a variety of nursing care, while arousal levels may be more likely to react to burdensome stresses. If the characteristics of these physiological indicators can be understood and effectively utilized during care, it may be possible to better identify and reduce patient stress during sedation management.

Neuromuscular blockade in mechanically ventilated pneumonia patients with moderate to severe hypoxemia: A multicenter retrospective study

BACKGROUND/PURPOSE

The benefit of neuromuscular blockades (NMBs) in critically ill patients receiving mechanical ventilation remains uncertain. Therefore, we aimed to investigate whether NMB use is associated with improved survival of mechanically ventilated pneumonia patients with moderate to severe hypoxemia.

METHODS

This retrospective multicenter study was conducted at five university-affiliated hospitals. Data of pneumonia patients aged 18 years and older who received mechanical ventilation between January 1, 2011, and December 31, 2020, were analyzed.

RESULTS

In a total of 1,130 patients, the mean patient age was 73.1 years (SD±12.6), and the overall mortality rate at 30 d was 29.5% (n = 333). NMB users had a higher 30 d mortality rate than NMB nonusers (33.9% vs. 26.8%, P = 0.014). After PS matching, the 30 d mortality rate was not significantly different between NMB users and nonusers (33.4% vs. 27.8%, p = 0.089). However, 90 d mortality rate was significantly increased in NMB users (39.7% vs. 31.9%, p = 0.021). Univariable Cox proportional hazard regression analyses showed that NMB use ≥ 3 d was significant risk factor for the 90 d mortality than those with < 3 d use (90 d mortality HR 1.39 [95% CI: 1.01-1.91], P = 0.045).

CONCLUSIONS

NMB use was not associated with lower 30 d mortality among mechanically ventilated pneumonia patients with moderate to severe hypoxemia. Rather, NMB users had higher 90 d mortality, furthermore, and NMB use ≥ 3 d was associated with a higher risk of long-term mortality compared to NMB use < 3 d. Therefore, care should be taken to avoid extended use of NMB in critically ill pneumonia patients during mechanical ventilation.

Excessive Sedation as a Risk Factor for Delirium: A Comparison between Two Cohorts of ARDS Critically Ill Patients with and without COVID-19

Excessive sedation is associated with poor outcome in critically ill acute respiratory distress syndrome (ARDS) patients. Whether this prognostic effect varies among ARDS patients with and without COVID-19 has yet to be determined. We compared the prognostic value of excessive sedation—in terms of delirium, length of stay in intensive care unit (ICU-LOS) and ICU mortality—between COVID-19 and non-COVID-19 critically ill ARDS patients. This was a second analysis of prospectively collected data in four European academic centers pertaining to 101 adult critically ill ARDS patients with and without COVID-19 disease. Depth of sedation (DOS) and delirium were monitored through processed electroencephalogram (EEG) and the Confusion Assessment Method for ICU (CAM-ICU). Our main exposure was excessive sedation and how it relates to the presence of delirium, ICU-LOS and ICU mortality. The criterion for excessive sedation was met in 73 (72.3%) patients; of these, 15 (82.2%) and 58 (69.1%) were in non-COVID-19 and COVID-19 ARDS groups, respectively. The criteria of delirium were met in 44 patients (60.3%). Moreover, excessive sedation was present in 38 (86.4%) patients with delirium (p < 0.001). ICU death was ascertained in 41 out of 101 (41.0%) patients; of these, 37 (90.2%) had excessive sedation (p < 0.001). The distribution of ICU-LOS among excessive-sedated and non-sedated patients was 22 (16−27) vs. 14 (10.5−19.5) days (p < 0.001), respectively. In a multivariable framework, excessive sedation was independently associated with the development of delirium (p = 0.001), increased ICU mortality (p = 0.009) and longer ICU-LOS (p = 0.000), but only in COVID-19 ARDS patients. Independent of age and gender, excessive sedation might represent a risk factor for delirium in COVID-19 ARDS patients. Similarly, excessive sedation shows to be an independent predictor of ICU-LOS and ICU mortality. The use of continuous EEG-based depth of sedation (DOS) monitoring and delirium assessment in critically ill COVID-19 patients is warranted.

The perinatal transition and early neonatal period in hypoplastic left heart syndrome is associated with reduced systemic and cerebral perfusion

BACKGROUND

The impact of the striking perinatal circulatory changes on blood flow distribution have not to date been well-examined in hypoplastic left heart syndrome (HLHS). This study aims to document perinatal redistribution of cardiac output in HLHS compared to healthy controls, to further understand the impact of perinatal transition on cerebral and systemic blood flow.

METHODS

Prospectively recruited HLHS cases (n=31) and healthy controls (n=19) underwent serial echocardiography from late fetal stages to 96 hours after birth. Combined cardiac output (CCO), systemic, pulmonary, cerebrovascular and splanchnic flow data were compared between HLHS neonates and controls, and the impact of vasoactive support and positive pressure ventilation (PPV) in HLHS patients examined.

RESULTS

In late gestation, CCO was similar between HLHS and controls, whereas middle cerebral artery (MCA) pulsatility index (PI) in HLHS was consistent with low cerebral vascular resistance. In the 96 hours after birth, CCO and pulmonary blood flow progressively increased in HLHS compared to controls (p<0.001), and CCO was further increased in HLHS neonates receiving vasoactive support (p=0.01). HLHS neonates had reduced systemic and 6-24hr superior vena cava (SVC) flow when compared to controls (p<0.001). Low systemic flow was further suggested by increased MCA and celiac artery PI at 6 - 48 hours in HLHS neonates (p<0.001). Systemic and SVC flow did not differ between those with and without vasoactive support.

CONCLUSION

We provide quantitative echocardiographic evidence associating impaired cerebral and systemic blood flow with perinatal hemodynamic changes in the preoperative HLHS neonate.

A study protocol for a multicentre, prospective, before-and-after trial evaluating the feasibility of implementing targeted SEDation after initiation of mechanical ventilation in the emergency department (The ED-SED Pilot Trial)

INTRODUCTION

Sedation is a cornerstone therapy in the management of patients receiving mechanical ventilation and is highly influential on outcome. Early sedation depth appears especially influential, as early deep sedation is associated with worse outcome when compared with light sedation. Our research group has shown that patients receiving mechanical ventilation in the emergency department (ED) are exposed to deep sedation commonly, and ED sedation depth is impactful on intensive care unit (ICU) care and clinical outcomes. While extensive investigation has occurred for patients in the ICU, comparatively little data exist from the ED. Given the influence that ED sedation seems to carry, as well as a lack of ED-based sedation trials, there is significant rationale to investigate ED-based sedation as a means to improve outcome.

METHODS AND ANALYSIS

This is a multicentre (n=3) prospective, before-and-after pilot trial examining the feasibility of implementing targeted sedation in the immediate postintubation period in the ED. A cohort of 344 patients receiving mechanical ventilation in ED will be included. Feasibility outcomes include: (1) participant recruitment; (2) proportion of Richmond Agitation-Sedation Scale (RASS) scores in the deep sedation range; (3) reliability (agreement) of RASS measurements performed by bedside ED nurses; and (4) adverse events. The proportion of deep sedation measurements before and after the intervention will be compared using the χ² test. Logistic regression will be used to compare before-and-after differences, adjusting for potential confounders. The inter-rater correlation coefficient will be used to assess paired observations between a study team member and bedside ED nurses, and to describe reliability of RASS measurements.

ETHICS AND DISSEMINATION

The Human Research Protection Office at Washington University in St. Louis School of Medicine has approved the study. The publication of peer-reviewed manuscripts and the presentation of abstracts at scientific meetings will be used to disseminate the work.

REGISTRATION

ClinicalTrials.gov identifier NCT04410783; Pre-results.

Comparison of Energy Expenditure in Mechanically Ventilated Septic Shock Patients in Acute and Recovery Periods via Indirect Calorimetry

BACKGROUND

Nutrition in intensive care units (ICUs) affects morbidity and mortality. We aimed to evaluate the energy expenditure of mechanically ventilated patients in early and late septic shock periods.

METHODS

This study retrospectively evaluated 28 mechanically ventilated septic shock patients (11 female/17 male) in a medical ICU. Indirect calorimetry (IC) measurement was performed for 24 hours during the acute and recovery periods of septic shock. The energy values calculated by Harris-Benedict equation (predicted resting energy expenditure [PREE]), measured by IC (measured resting energy expenditure [MREE]), and given to each patient were obtained in the acute and recovery periods.

RESULTS

The mean age was 67.46 ± 14.92 (36-91) years. The MREE was 2741.1 ± 706.3 kcal/d (38.61 ± 11.44 kcal/kg/d) and 2332.8 ± 426.6 kcal/d (32.65 ± 7.8 kcal/kg/d) in the acute and recovery periods, respectively, and showed significant differences (P = 0.001). The patients' energy intake was 1152.7 ± 207.1 kcal/d and 1542.7 ± 433.3 kcal/d in the acute and recovery periods, respectively. A significant difference existed between energy intake and MREE during the acute and recovery periods (P < 0.001 for both).

CONCLUSION

Our findings showed that energy expenditure increases in septic shock. Significant differences existed between MREE, PREE, and energy intake, which were not correlated. The MREE was higher in the acute period. Despite the increasing energy requirement, the PREE and energy intake were well below MREE. For better clinical outcomes, each patient's energy expenditure must be closely monitored and evaluated using intermittent IC measurements.

Neuromuscular Blockade Applicability in Early Acute Respiratory Distress Syndrome

Neuromuscular blockade with deep sedation appears to offer no advantage to patients with acute respiratory distress syndrome who can be managed with lighter sedation. In those patients requiring deep sedation, the addition of neuromuscular blockade may be beneficial.

The effect of cisatracurium infusion on the energy expenditure of critically ill patients: an observational cohort study

Background

Both overfeeding and underfeeding of intensive care unit (ICU) patients are associated with worse outcomes. A reliable estimation of the energy expenditure (EE) of ICU patients may help to avoid these phenomena. Several factors that influence EE have been studied previously. However, the effect of neuromuscular blocking agents on EE, which conceptually would lower EE, has not been extensively investigated.

Methods

We studied a cohort of adult critically ill patients requiring invasive mechanical ventilation and treatment with continuous infusion of cisatracurium for at least 12 h. The study aimed to quantify the effect of cisatracurium infusion on EE (primary endpoint). EE was estimated based on ventilator-derived VCO₂ (EE in kcal/day = VCO₂ × 8.19). A subgroup analysis of septic and non-septic patients was performed. Furthermore, the effects of body temperature and sepsis on EE were evaluated. A secondary endpoint was hypercaloric feeding (> 110% of EE) after cisatracurium infusion.

Results

In total, 122 patients were included. Mean EE before cisatracurium infusion was 1974 kcal/day and 1888 kcal/day after cisatracurium infusion. Multivariable analysis showed a significantly lower EE after cisatracurium infusion (MD − 132.0 kcal (95% CI − 212.0 to − 52.0; p = 0.001) in all patients. This difference was statistically significant in both sepsis and non-sepsis patients (p = 0.036 and p = 0.011). Non-sepsis patients had lower EE than sepsis patients (MD − 120.6 kcal; 95% CI − 200.5 to − 40.8, p = 0.003). Body temperature and EE were positively correlated (Spearman’s rho = 0.486, p < 0.001). Hypercaloric feeding was observed in 7 patients.

Conclusions

Our data suggest that continuous infusion of cisatracurium in mechanically ventilated ICU patients is associated with a significant reduction in EE, although the magnitude of the effect is small. Sepsis and higher body temperature are associated with increased EE. Cisatracurium infusion is associated with overfeeding in only a minority of patients and therefore, in most patients, no reductions in caloric prescription are necessary.

Use of Predictive Equations for Energy Prescription Results in Inaccurate Estimation in Trauma Patients

BACKGROUND

Overfeeding and underfeeding are associated with poor clinical outcomes. In the absence of indirect calorimetry (IC), the Society of Critical Care Medicine/ASPEN recommend prescribing 25-30 kcal/kg. The Harris-Benedict equation (HBE) multiplied by a stress factor is commonly applied in critically ill patients. We describe the difference between estimated and actual energy needs in critically injured patients.

METHODS

From March to November 2018, we collected demographics and energy needs determined by continuous IC (started within 4 days) in intubated adults. Ideal or adjusted body weight was used for 25-30 kcal/kg, and HBE was multiplied by a 1.3 stress factor (1.3HBE). Daily requirements up to 14 days, extubation, or death were calculated using all 3 methods and compared with IC.

RESULTS

Fifty-five subjects were included. Median age was 38 [27-58] years, 38 (69%) were male, body mass index was 28 [25-33] kg/m² , and Acute Physiology and Chronic Health Evaluation II score was 17 [14-24] Mechanism of injury was blunt (38, 69%), penetrating (9, 16%), and burn (8, 15%). By day 14, compared with measured energy requirements by IC, the other methods could result in a cumulative 1827-kcal (+7%) surplus (1.3HBE), a 1313-kcal (-5%) deficit (25 kcal/kg), or a 3950-kcal (+14%) surplus (30 kcal/kg) per patient over a median 9 days.

CONCLUSION

In critically injured patients, predictive equations for energy needs do not account for dynamic metabolic changes over time and could result in underfeeding or overfeeding. Adjusting daily prescription based on continuous IC may result in better individualized treatment.

Systematic review of factors associated with energy expenditure in the critically ill

BACKGROUND AND AIMS

Indirect calorimetry is the reference standard for energy expenditure measurement. Predictive formulae that replace it are inaccurate. Our aim was to review the patient and clinical factors associated with energy expenditure in critically ill patients.

METHODS

We conducted a systematic review of the literature. Eligible studies were those reporting an evaluation of factors and energy expenditure. Energy expenditure and factor associations with p-values were extracted from each study, and each factor was classified as either significantly, indeterminantly, or not associated with energy expenditure. Regression coefficients were summarized as measures of central tendency and spread. Metanalysis was performed on correlations.

RESULTS

The search strategy yielded 8521 unique articles, 307 underwent full text review, and 103 articles were included. Most studies were in adults. There were 95 factors with 352 evaluations. Minute volume, weight, age, % body surface area burn, sedation, post burn day, and caloric intake were significantly associated with energy expenditure. Heart rate, fraction of inspired oxygen, respiratory rate, respiratory disease diagnosis, positive end expiratory pressure, intensive care unit days, C- reactive protein, and size were not associated with energy expenditure. Multiple factors (n = 37) were identified with an unclear relationship with energy expenditure and require further evaluation.

CONCLUSIONS

An important interval step in the development of accurate formulae for energy expenditure estimation is a better understanding of relationships between patient and clinical factors and energy expenditure. The review highlights the limitations of currently available data, and identifies important factors that are not included in current prediction formulae of the critically ill.

An Exploratory Retrospective Study of Factors Affecting Energy Expenditure in Critically Ill Children

BACKGROUND

Accurate measurement of energy expenditure is not widely available. Patient and clinical factors associated with energy expenditure have been poorly explored, leading to errors in estimation formulae. The objective of this study was to determine clinical factors associated with measured energy expenditure (MEE), expressed in kcal/kg/d, in critically ill children.

METHODS

This was a retrospective study at 2 Canadian pediatric intensive care units (ICUs). Patients were mechanically ventilated children who had 1 or more MEE using indirect calorimetry. Associations between MEE and 28 clinical factors were evaluated in univariate regression and 16 factors in a multivariate regression model accounting for repeated measurements.

RESULTS

Data from 239 patients (279 measurements) were analyzed. Median (Q1, Q3) MEE was 34.8 (26.8, 46.2) kcal/kg/d. MEE was significantly associated with weight, heart rate, diastolic blood pressure, ICU day of indirect calorimetry (P = 0.004), minute ventilation, vasoactive inotropic score (P = 0.004), opioids, chloral hydrate, dexmedetomidine, inhaled salbutamol (P = 0.02), and propofol dose (all P < 0.0001 unless otherwise specified) in the final multivariate regression model.

CONCLUSIONS

This study demonstrated association between MEE (kcal/kg/d) and factors not previously explored in pediatric critical illness. Further evaluation of these factors to confirm associations and more precisely quantify the magnitude of effect is required to support refinement of formulae to estimate energy expenditure.

Evaluation of Factors Associated with Hypermetabolism and Hypometabolism in Critically Ill AKI Patients

Acute kidney injury (AKI) is a frequent and serious condition with high mortality. The presence of hypermetabolism may be a factor related to poorer prognosis. This study evaluated the resting energy expenditure (REE) of intensive care unit (ICU) patients with severe AKI using indirect calorimetry (IC) and identified factors associated with metabolism categories. Patients were evaluated through measurement of REE and estimation of basal energy expenditure (BEE) using the Harris⁻Benedict equation. Metabolism categories were as follows: hypermetabolism (REE/BEE > 1.3) and hypometabolism (REE/BEE < 0.9). The metabolism categories were compared using ANOVA and the chi-square test. Variables were analyzed by multiple logistic regression tests. Also, survivors and non-survivors were compared using Student&rsquo;s t-tests along with Cox regression tests. Kaplan⁻Meier survival curves were also performed. We evaluated 124 patients with a mean age of 61.08 &plusmn; 16.6 years. Sixty-four patients were hypermetabolic (62%) and 18 were hypometabolic (14%). Vasoactive drug (VAD) dose and younger age were independently associated with hypermetabolism. The survival analysis was not associated with metabolism categorization. In conclusion, patients with severe AKI are mostly hypermetabolic and hypermetabolic patients of a lower age receiving treatment with higher VAD doses. The only factors associated with death were protein intake and VAD dose.

Influence of different dialysis modalities in the measurement of resting energy expenditure in patients with acute kidney injury in ICU

BACKGROUND

Currently, the execution of indirect calorimetry, which is considered the gold standard for measuring energy expenditure, is not indicate during dialysis, and it may interfere on nutritional therapy of these patients. This study aimed to evaluate the resting energy expenditure (REE) in patients with severe acute kidney injury treated by different modalities of dialysis and to identify whether dialysis influences on REE.

METHODS

This was a prospective cohort study that evaluated patients admitted in intensive care units with diagnosis of acute kidney injury AKIN-3, mechanically ventilated, and submitted to conventional hemodialysis (CHD), extended hemodialysis (EHD) or high volume peritoneal dialysis (HVPD). Indirect calorimetry was performed at pre dialysis time and during the dialysis procedure. Parameters that could change REE were also evaluated.

RESULTS

One-hundred patients undergoing 290 dialysis sessions were evaluated, with mean age 60.3 ± 17 years, 69% were male and 74% have died. There was no significant difference between REE of predialysis time and during dialysis time (2156 ± 659 kcal vs. 2100 ± 634 kcal, respectively, p = 0.15). No difference was observed in the REE before and during dialysis of different modalities. There were no differences between parameters pre and during dialysis of each modality. There was only a difference in norepinephrine dose, which was higher in pre dialysis time in HVPD and EHD modalities, compared with CHD modality. Moreover, during dialysis time, EHD modality had significantly higher VAD compared to other dialysis modalities.

CONCLUSION

The three evaluated modalities did not change REE. Indirect calorimetry can be performed during dialysis procedures and there was no difference between ventilation parameters, sedatives use, body temperature and VAD in both moments.

Increased Resting Energy Expenditure after Endovascular Coiling for Subarachnoid Hemorrhage

BACKGROUND

Appropriate nutritional care from the acute stage is essential for improved functional outcomes and reduced mortality in patients with subarachnoid hemorrhage (SAH). Although endovascular coiling is increasingly being used as an alternative to neurosurgical clipping and craniotomy for ruptured aneurysms, the resting energy expenditure (REE) of patients treated with this new technique has not been systemically evaluated.

METHODS

We measured REE values by indirect calorimetry in 12 SAH patients treated with endovascular coiling. We averaged the REE measurements obtained on days 1 and 7 after endovascular coiling, and then we statistically compared the mean REE values with those in 30 patients with acute cerebral infarction (ACI) by the Wilcoxon rank-sum test (P <.05). Next, we calculated the ratio of measured REE values to the values estimated using the Harris-Benedict equation to adjust for demographic differences in sex, weight, height, and age between the groups.

RESULTS

The ratios were significantly higher in SAH patients (median value, 1.12; interquartile range, 1.05-1.23) than in ACI patients (median value, 1.02; interquartile range, .97-1.09).

CONCLUSIONS

Because endovascular coiling is less invasive than neurosurgical clipping, the observed increase in REE was attributed to metabolic changes after SAH. To provide optimal nutritional care to SAH patients from the acute stage, clinicians should be aware of this change in REE.

Clinical Guide for the Use of Metabolic Carts: Indirect Calorimetry--No Longer the Orphan of Energy Estimation

Critically ill patients often require nutrition support, but accurately determining energy needs in these patients is difficult. Energy expenditure is affected by patient characteristics such as weight, height, age, and sex but is also influenced by factors such as body temperature, nutrition support, sepsis, sedation, and therapies. Using predictive equations to estimate energy needs is known to be inaccurate. Therefore, indirect calorimetry measurement is considered the gold standard to evaluate energy needs in clinical practice. This review defines the indications, limitations, and pitfalls of this technique and gives practice suggestions in various clinical situations.

Resting energy expenditure and substrate oxidation rates correlate to temperature and outcome after cardiac arrest - a prospective observational cohort study

INTRODUCTION

Targeted temperature management improves outcome after cardiopulmonary resuscitation. Reduction of resting energy expenditure might be one mode of action. The aim of this study was to correlate resting energy expenditure and substrate oxidation rates with targeted temperature management at 33°C and outcome in patients after cardiac arrest.

METHODS

This prospective, observational cohort study was performed at the department of emergency medicine and a medical intensive care unit of a university hospital. Patients after successful cardiopulmonary resuscitation undergoing targeted temperature management at 33°C for 24 hours with subsequent rewarming to 36°C and standardized sedation, analgesic and paralytic medication were included. Indirect calorimetry was performed five times within 48 h after cardiac arrest. Measurements were correlated to outcome with repeated measures ANOVA, linear and logistic regression analysis.

RESULTS

In 25 patients resting energy expenditure decreased 20 (18 to 27) % at 33°C compared to 36°C without differences between outcome groups (favourable vs. unfavourable: 25 (21 to 26) vs. 21 (16 to 26); P = 0.5). In contrast to protein oxidation rate (favourable vs. unfavourable: 35 (11 to 68) g/day vs. 39 (7 to 75) g/day, P = 0.8) patients with favourable outcome had a significantly higher fat oxidation rate (139 (104 to 171) g/day vs. 117 (70 to 139) g/day, P <0.05) and a significantly lower glucose oxidation rate (30 (-34 to 88) g/day vs. 77 (19 to 138) g/day; P < 0.05) as compared to patients with unfavourable neurological outcome.

CONCLUSIONS

Targeted temperature management at 33°C after cardiac arrest reduces resting energy expenditure by 20% compared to 36°C. Glucose and fat oxidation rates differ significantly between patients with favourable and unfavourable neurological outcome.

TRIAL REGISTRATION

Clinicaltrials.gov NCT00500825. Registered 11 July 2007.

Assessing, monitoring and managing continuous intravenous sedation for critically ill adult patients and implications for emergency nursing practice: A systematic literature review

BACKGROUND

Critically ill mechanically ventilated patients in ED have complex needs; chief among these is adequate sedation in addition to effective pain-relief. Emergency nurses are increasingly responsible sedation and analgesia for this complex cohort of patients. The aim of this review was to examine (1) the evidence around assessing, monitoring and managing continuous intravenous sedation for critically ill adult patients, and (2) the implications for emergency nursing practice.

STUDY DESIGN

Systematic review.

METHOD

The review of literature extended from 1946 to 2013 and examined peer review journal articles, policy and guidelines to provide a more complex understanding of a phenomenon of concern. A total of 98 articles were incorporated and comprehensively examined.

RESULTS

Analysis of the literature identified several implications for emergency nursing practice and the management of continuous intravenous sedation: workload, education, monitoring and assessing sedation and policy.

CONCLUSION

Limited literature was found that directly addressed Australasian emergency nursing practices' in managing on-going intravenous sedation and analgesia for patients. Balancing patient sedation and analgesia requires highly complex knowledge, skills and expertise; the degree of education and training required is above that obtained during pre-registration nurse training. No state or national models of education or training were identified to support ED nurses' practices in managing sedation. Little research has addressed the safety of continuous sedation use in ED.

Nutrition Monitoring in the PICU

The ideal set of variables for nutritional monitoring that may correlate with patient outcomes has not been identified. This is particularly difficult in the PICU patient because many of the standard modes of nutritional monitoring, although well described and available, are fraught with difficulties. Thus, repeated anthropometric and laboratory markers must be jointly analyzed but individually interpreted according to disease and metabolic changes, in order to modify and monitor the nutritional treatment. In addition, isotope techniques are neither clinically feasible nor compatible with the multiple measurements needed to follow progression. On the other hand, indirect alternatives exist but may have pitfalls, of which the clinician must be aware. Risks exist for both overfeeding and underfeeding of PICU patients so that an accurate monitoring of energy expenditure, using targeted indirect calorimetry, is necessary to avoid either extreme. This is very important, since the monitoring of the nutritional status of the critically ill child serves as a guide to early and effective nutritional intervention.

Indirect calorimetry reveals that better monitoring of nutrition therapy in pediatric intensive care is needed

BACKGROUND

Monitoring nutrition therapy is essential in the care of critically ill children, but the risk of nutrition failure seems to remain. The aims of the present study were to examine the prevalence of underfeeding, adequate feeding, and overfeeding in mechanically ventilated children and to identify barriers to the delivery of nutrition support.

MATERIALS AND METHODS

Children aged 0-14 years who fulfilled the criteria for indirect calorimetry were enrolled in this prospective, observational study and were studied for up to 5 consecutive days. Actual energy intake was recorded and compared with the required energy intake (measured energy expenditure plus 10%); energy intake was classified as underfeeding (<90% of required energy intake), adequate feeding (90%-110%), or overfeeding (>110%). The reasons for interruptions to enteral and parenteral nutrition were recorded.

RESULTS

In total, 104 calorimetric measurements for 140 total days were recorded for 30 mechanically ventilated children. Underfeeding, adequate feeding, and overfeeding occurred on 21.2%, 18.3%, and 60.5% of the 104 measurement days, respectively. There was considerable variability in the measured energy expenditure between children (median, 37.2 kcal/kg/d; range, 16.81-66.38 kcal/kg/d), but the variation within each child was small. Respiratory quotient had low sensitivity of 21% and 27% for detecting underfeeding and overfeeding, respectively. Fasting for procedures was the most frequent barrier that led to interrupted nutrition support.

CONCLUSION

The high percentage of children (~61%) who were overfed emphasizes the need to measure energy needs by using indirect calorimetry.

Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit

OBJECTIVE

To revise the "Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult" published in Critical Care Medicine in 2002.

METHODS

The American College of Critical Care Medicine assembled a 20-person, multidisciplinary, multi-institutional task force with expertise in guideline development, pain, agitation and sedation, delirium management, and associated outcomes in adult critically ill patients. The task force, divided into four subcommittees, collaborated over 6 yr in person, via teleconferences, and via electronic communication. Subcommittees were responsible for developing relevant clinical questions, using the Grading of Recommendations Assessment, Development and Evaluation method (http://www.gradeworkinggroup.org) to review, evaluate, and summarize the literature, and to develop clinical statements (descriptive) and recommendations (actionable). With the help of a professional librarian and Refworks database software, they developed a Web-based electronic database of over 19,000 references extracted from eight clinical search engines, related to pain and analgesia, agitation and sedation, delirium, and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain, agitation/sedation, and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method, with anonymous voting by all task force members using E-Survey (http://www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high (A), moderate (B), or low/very low (C). The strength of recommendations was ranked as strong (1) or weak (2), and either in favor of (+) or against (-) an intervention. A strong recommendation (either for or against) indicated that the intervention's desirable effects either clearly outweighed its undesirable effects (risks, burdens, and costs) or it did not. For all strong recommendations, the phrase "We recommend …" is used throughout. A weak recommendation, either for or against an intervention, indicated that the trade-off between desirable and undesirable effects was less clear. For all weak recommendations, the phrase "We suggest …" is used throughout. In the absence of sufficient evidence, or when group consensus could not be achieved, no recommendation (0) was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflict of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding.

CONCLUSION

These guidelines provide a roadmap for developing integrated, evidence-based, and patient-centered protocols for preventing and treating pain, agitation, and delirium in critically ill patients.

What are the factors that influence the attainment of satisfactory energy intake in pediatric intensive care unit patients receiving enteral or parenteral nutrition?

OBJECTIVE

Children admitted to the intensive care unit (ICU) are at risk of inadequate energy intake. Although studies have identified factors contributing to an inadequate energy supply in critically ill children, they did not take into consideration the length of time during which patients received their estimated energy requirements after having achieved a satisfactory energy intake. This study aimed to identify factors associated with the non-attainment of estimated energy requirements and consider the time this energy intake is maintained.

METHODS

This was a prospective study involving 207 children hospitalized in the ICU who were receiving enteral and/or parenteral nutrition. The outcome variable studied was whether 90% of the estimated basal metabolic rate was maintained for at least half of the ICU stay (satisfactory energy intake). The exposure variables for outcome were gender, age, diagnosis, use of vasopressors, malnutrition, route of nutritional support, and Pediatric Index of Mortality and Pediatric Logistic Organ Dysfunction scores.

RESULTS

Satisfactory energy intake was attained by 20.8% of the patients, within a mean time of 5.07 ± 2.48 d. In a multivariable analysis, a diagnosis of heart disease (odds ratio 3.62, 95% confidence interval 1.03-12.68, P = 0.045) increased the risk of insufficient energy intake, whereas malnutrition (odds ratio 0.43, 95% confidence interval 0.20-0.92, P = 0.030) and the use of parenteral nutrition (odds ratio 0.34, 95% confidence interval 0.15-0.77, P = 0.001) were protective factors against this outcome.

CONCLUSION

A satisfactory energy intake was reached by a small proportion of patients during their ICU stay. Heart disease was an independent risk factor for the non-attainment of satisfactory energy intake, whereas malnutrition and the use of parenteral nutrition were protective factors against this outcome.

Energy expenditure in patients with severe head injury: controlled normothermia with sedation and neuromuscular blockade

OBJECTIVES

Providing optimal caloric intake is important for patients with severe traumatic brain injury. Insufficient nutrition worsens prognosis, and excessive nutrition may lead to complications such as weaning delay from mechanical ventilation. However, using controlled normothermia with sedation and neuromuscular blockade for patients with anticipated severe brain edema, the optimal caloric intake is still unclear.

METHODS

Ten patients with severe traumatic brain injury were studied. All patients received midazolam and vecuronium or pancuronium to control body temperature to 36.0°C. Energy expenditure was measured using indirect calorimetry. Age, body height, body weight, heart rate, blood pressure, body temperature, and minute ventilation volume were evaluated at the time of the study. Differences between the mean measured energy expenditures (MEEs) and predicted basal energy expenditures (PEEs from the Harris-Benedict equation) were analyzed using paired t test. Furthermore, the relationships between these variables and MEEs were analyzed with multiple regression analysis.

RESULTS

The result of MEE was 1279±244 kcal/d. When compared with PEE, MEE/PEE was 87.2% ± 10%. Multiple regression analysis showed that age, body height, body weight, heart rate, and minute ventilation volume were related with MEE.

CONCLUSIONS

Energy expenditure in patients with severe traumatic brain injury who need mechanical ventilation and have received controlled normothermia with sedation and neuromuscular blockade was 13% less than predicted basal levels. Energy expenditure might be obtained from age, body height, body weight, heart rate, and minute ventilation.

Electroacupuncture reduces the dose of midazolam monitored by the bispectral index in critically ill patients with mechanical ventilation: an exploratory study

OBJECTIVE

Electroacupuncture, a modern variation on a traditional Chinese treatment, might be useful for sedation and analgesia. This study aims to investigate whether electroacupuncture can modify the dose of midazolam monitored by the bispectral index (BIS) in critically ill patients with mechanical ventilation.

METHODS

Orotracheally intubated patients undergoing mechanical ventilation were randomly assigned into three groups (groups A, B and C). All patients were given an intravenous infusion of midazolam. Patients in group A received no additional treatment. Patients in group B were given acupuncture without electrical stimulation at acupuncture points GV24 and EX-HN3 (Yintang) for 6 h simultaneously, and patients in group C were given electroacupuncture to the same points as in group B.

RESULTS

Maintaining the BIS between 60 and 80, the hourly mean one dose of midazolam within the first 6 h after sedation in group C was 0.05 (±0.02 mg/kg per hour), which was significantly lower than both group A (0.08 ± 0.03 mg/kg per hour, p<0.001) and group B (0.07 ± 0.01 mg/kg per hour, p<0.021). The doses in groups A and B showed no significant difference. Between-group comparison analysis of hepatic and renal function and severe adverse reactions all showed no significant difference between the three groups.

CONCLUSIONS

Electroacupuncture appears to reduce markedly the dose of sedative drug required in critically ill patients with mechanical ventilation monitored by BIS, without any obvious severe adverse action, and larger studies to confirm the effect are justified.

A report of anticipated benefits of functional electrical stimulation after spinal cord injury

BACKGROUND

Functional electrical stimulation (FES) has been regularly used to offset several negative body composition and metabolic adaptations following spinal cord injury (SCI). However, the outcomes of many FES trials appear to be controversial and incoherent.

OBJECTIVE

To document the potential consequences of several factors (e.g. pain, spasms, stress and lack of dietary control) that may have attenuated the effects on body composition and metabolic profile despite participation in 21 weeks of FES training.

PARTICIPANT

A 29-year-old man with T6 complete SCI participated in 21 weeks of FES, 4 days per week.

METHODS

Prior to and following training, the participant performed arm-crank-graded exercise testing to measure peak VO(2). Tests conducted included anthropometrics and dual energy X-ray absorptiometry body composition assessments, resting energy expenditure, plasma lipid profiles and intravenous glucose tolerance tests.

RESULTS

The participant frequently reported increasing pain, stress and poor eating habits. VO(2) peak decreased by 2.4 ml/kg/minute, body mass increased by 8.5 kg, and body mass index increased from 25 to 28 kg/m(2). Waist and abdominal circumferences increased by 2-4 cm, while %fat mass increased by 5.5%. Absolute increases in fat mass and fat-free mass of 8.4 and 1 kg, respectively, were reported. Fasting and peak plasma glucose increased by 12 and 14.5%, while lipid panel profiles were negatively impacted.

CONCLUSION

Failure to control for the listed negative emerging factors may obscure the expected body composition and metabolic profile adaptations anticipated from FES training.

Validation and clinical feasibility of nitrogen washin/washout functional residual capacity measurements in children

BACKGROUND

The functional residual capacity (FRC) is an important parameter in pediatric respiratory monitoring but it is difficult to assess in the clinical setting. We have introduced a modified N(2) washout method utilizing a change of F(I)O(2) of 0.1 for FRC measurement in adult respiratory monitoring. This study validated the algorithm in a pediatric lung model and investigated the stability and feasibility in a pediatric peri-operative and intensive care setting.

METHODS

The lung model was ventilated in combinations of ventilatory modes, CO(2) production, model FRC and respiratory rates. Sixteen children from 10 days to 5 years were studied peri-operatively with controlled ventilation using a Mapleson D system and in the intensive care unit using a Servo-i ventilator in a supported spontaneous mode. FRC was measured during stable metabolic, respiratory and circulatory periods at positive end expiratory pressure of 3-4 and 7-8 cmH(2)O.

RESULTS

In the model and in the clinical setting, we found an excellent agreement between washout and washin measurements of FRC as well as acceptable coefficients of repeatability.

CONCLUSION

FRC was satisfactorily measured by a modified N(2) algorithm and may be included as a monitoring variable in pediatric respiratory care. Pediatric FRC monitoring demands strictly stable conditions as measurements are performed close to the limits of the monitor's specifications.

Increased energy expenditure and glucose oxidation during acute nontraumatic skin pain in humans

BACKGROUND AND OBJECTIVE

Tissue injury is accompanied by pain and results in increased energy expenditure, which may promote catabolism. The extent to which pain contributes to this sequence of events is not known.

METHODS

In a cross-over design, 10 healthy volunteers were examined on three occasions; first, during self-controlled nontraumatic electrical painful stimulus to the abdominal skin, maintaining an intensity of 8 on the visual analogue scale (0-10). Next, the electrical stimulus was reproduced during local analgesia and, finally, there was a control session without stimulus. Indirect calorimetry and blood and urine sampling was done in order to calculate energy expenditure and substrate utilization.

RESULTS

During pain stimulus, energy expenditure increased acutely and reversibly by 62% (95% confidence interval, 43-83), which was abolished by local analgesia. Energy expenditure paralleled both heart rate and blood catecholamine levels. The energy expenditure increase was fuelled by all energy sources, with the largest increase in glucose utilization.

CONCLUSION

The pain-related increase in energy expenditure was possibly mediated by adrenergic activity and was probably to a large extent due to increased muscle tone. These effects may be enhanced by cortical events related to the pain. The increase in glucose consumption favours catabolism. Our findings emphasize the clinical importance of pain management.

Age-dependent relationship between bispectral index and sedation level

STUDY OBJECTIVE

To determine the relationship between bispectral index (BIS) and sedation.

DESIGN

Prospective, observational clinical study.

SETTING

Intensive care unit of a public hospital in Japan.

PATIENTS

22 ASA physical status I, II, and III middle-aged (18-65 yrs) and elderly (>65 yrs) patients receiving postoperative sedation with midazolam.

INTERVENTIONS

Patients were allocated to two groups: Group M was composed of middle-aged patients (<65 yrs) and Group H elderly patients (>65 yrs). Midazolam was administered at a bolus dose of 0.1 mg/kg, followed by a continuous dose of 0.04 mg/kg per hour, which was adjusted every two hours to achieve a target level of sedation at 3-6 on the Ramsay Sedation Scale (RSS); buprenorphine was administered at a constant rate (0.625 microg kg(-1) hr(-1)).

MEASUREMENTS

BIS value, RSS, midazolam dose, body temperature (BT), heart rate, dopamine dose, and mean arterial pressure were recorded every two hours by an independent nurse. Data were analyzed using Spearman rank correlation and the Mann-Whitney U test.

MAIN RESULTS

BIS values decreased depending on depth of sedation; a significant correlation was noted between groups in RSS and BIS. The BIS values at levels of RSS 5 and 6 were significantly lower in Group H than Group M.

CONCLUSION

BIS correlated with sedation depth, with BIS scores in group H than group M at a deep sedation depth.

[Effects of sedative agents on metabolic demand]

Literature about the effects of sedative drugs on the metabolic demand of critically ill patients is relatively old and of relatively poor quality. Most are experimental or observational studies. Level of evidence is therefore relatively low corresponding to "expert opinion". The effects of analgesics and hypnotics on tissue metabolic demand associated remain difficult to be adequately quantified. They are essentially related to a decreased neuro-humoral response to stress. This response involves principally the sympathetic system, which could be effectively blocked by most of the anesthetic agents. Other factors could participate to the observed reduction in tissue metabolic demand, as a decrease in spontaneous muscular activity, a reduction in work of breathing and/or a decrease in body temperature. The relative contribution of these different factors will depend on the clinical situation of the patient. Proper effects of anesthetic agents on cellular metabolism are limited as they can only decrease the functional component of this metabolism especially at the level of the heart and to some extent, at the level of the brain. Although the control of the sympathetic activity may be beneficial in critically ill patient, complete sympathetic blockade could be detrimental. Indeed, when oxygen transport to the tissues is acutely reduced, the sympathetic system plays an important role in the redistribution of blood flow according of local metabolic demand. The complete blunting of the neuro-humoral response to stress and therefore of the sympathetic system alters this physiological mechanism and results in a decrease in tissue oxygen extraction capabilities. An imbalance between tissue oxygen demand and delivery could appear with the development of cellular hypoxia. The institution of sedation in a critically ill patient requires careful evaluation of the sedation level using an appropriate scale. In patients in whom a reduction in metabolic demand is specifically requested, but also in patients with limited oxygen transport, the effects of sedative agents on the oxygen consumption-oxygen delivery relationship must also be monitored. The choice of the different agents to be administered will depend on the predefined objectives. As far as intravenous agents are concerned, there is no evidence than one association is more efficient in reducing patient's metabolic demand.

Comparison of oxygen consumption calculated by Fick's principle (using a central venous catheter) and measured by indirect calorimetry

We investigated the clinical usefulness of the Fick method using central venous oxygen saturation ScvO2 and cardiac output (CO) measured by pulse dye densitometry (PDD) for monitoring oxygen consumption VO2. This prospective clinical study was performed in 28 mechanically ventilated postoperative patients after major abdominal surgery. VO2 was determined by two methods, i.e., the Fick method and indirect calorimetry. The Fick method was employed using CO measured by PDD and VO2 obtained from a central venous catheter (CVC). VO2 measured by indirect calorimetry was averaged for 15 min. Fifty-six sets of measurements were performed. VO2 values determined by the Fick method were significantly lower than those measured by indirect calorimetry (110 +/- 29 vs 148 +/- 28 ml x min(-1) x m(-2); P < 0.01). Bland and Altma analysis showed that the mean bias and precision were 33 ml x min(-1) x m(-2) and 32 ml x min(-1) x m(-2), respectively. The correlation between the two measurements of VO2 was weak (r (2) = 0.145; P = 0.0038), indicating that the Fick method using PDD and ScvO2 is not clinically acceptable for the monitoring of VO2.

Controversies in the determination of energy requirements

To avoid any negative outcomes associated with under- or overfeeding it is essential to estimate nutrient requirements before commencing nutrition support. The energy requirements of an individual vary with current and past nutritional status, clinical condition, physical activity and the goals and likely duration of treatment. The evidence-base for prediction methods in current use, however, is poor and the equations are thus open to misinterpretation. In addition, most methods require an accurate measurement of current weight, which is problematic in some clinical situations. The estimation of energy requirements is so challenging in some conditions, e.g. critical illness, obesity and liver disease, that it is recommended that expenditure be measured on an individual basis by indirect calorimetry. Not only is this technique relatively expensive, but in the clinical setting there are several obstacles that may complicate, and thus affect the accuracy of, any such measurements. A review of relevant disease-specific literature may assist in the determination of energy requirements for some patient groups, but the energy requirements for a number of clinical conditions have yet to be established. Regardless of the method used, estimated energy requirements should be interpreted with care and only used as a starting point. Practitioners should regularly review the patient and reassess requirements to take account of any major changes in clinical condition, nutritional status, activity level and goals of treatment. There is a need for large randomised controlled trials that compare the effects of different levels of feeding on clinical outcomes in different disease states and care settings.

Resting energy expenditure during mechanical ventilation and its relationship with the type of lesion

BACKGROUND

Resting energy expenditure (REE) of critically ill patients is usually calculated according to basal energy expenditure obtained from Harris-Benedict equations traditionally corrected by different stress factors, resulting in a variable accuracy for the individual patient. The objective of this study was to investigate whether or not the type of lesion affects the metabolism level of critically ill patients treated with mechanical ventilation. We performed a retrospective study measuring the REE of critically ill patients with 3 different types of lesions (trauma, medical, surgical) who were treated with mechanical ventilation and sedation. Each lesion group of patients was matched with another group, differing in the type of lesion, according to gender, age, and weight.

METHODS

Eighty-seven from a database of 175 critically ill patients undergoing indirect calorimetry were necessary for matching. Twenty matched pairs of patients for each of the following different type of lesion were obtained: medical vs surgical, medical vs trauma, and surgical vs trauma.

RESULTS

The mean REE difference was 52 kcal/d (95% confidence interval [CI] of -136 -241 kcal/d) for the medical vs surgical group, 5 kcal/d (95% CI -236 -247 kcal/d) for the medical vs trauma group and 43 kcal/d (95% CI of -132-219 kcal/d) for the surgical vs trauma group. No statistically significant differences between groups were found in the measured REE. We did not find statistically significant differences in the measured REE of patients with and without infection.

CONCLUSIONS

Critically ill patients with different types of lesion treated with mechanical ventilation have similar measured REE.

Accurate Determination of Energy Needs in Hospitalized Patients

OBJECTIVE

To evaluate the accuracy of seven predictive equations, including the Harris-Benedict and the Mifflin equations, against measured resting energy expenditure (REE) in hospitalized patients, including patients with obesity and critical illness.

DESIGN

A retrospective evaluation using the nutrition support service database of a patient cohort from a similar timeframe as those used to develop the Mifflin equations.

SUBJECTS/SETTING

All patients with an ordered nutrition assessment who underwent indirect calorimetry at our institution over a 1-year period were included.

INTERVENTION

Available data was applied to REE predictive equations, and results were compared to REE measurements.

MAIN OUTCOME MEASURES

Accuracy was defined as predictions within 90% to 110% of the measured REE. Differences >10% or 250 kcal from REE were considered clinically unacceptable.

STATISTICAL ANALYSES PERFORMED

Regression analysis was performed to identify variables that may predict accuracy. Limits-of-agreement analysis was carried out to describe the level of bias for each equation.

RESULTS

A total of 395 patients, mostly white (61%) and African American (36%), were included in this analysis. Mean age+/-standard deviation was 56+/-18 years (range 16 to 92 years) in this group, and mean body mass index was 24+/-5.6 (range 13 to 53). Measured REE was 1,617+/-355 kcal/day for the entire group, 1,790+/-397 kcal/day in the obese group (n=51), and 1,730+/-402 kcal/day in the critically ill group (n=141). The most accurate prediction was the Harris-Benedict equation when a factor of 1.1 was multiplied to the equation (Harris-Benedict 1.1), but only in 61% of all the patients, with significant under- and over-predictions. In the patients with obesity, the Harris-Benedict equation using actual weight was most accurate, but only in 62% of patients; and in the critically ill patients the Harris-Benedict 1.1 was most accurate, but only in 55% of patients. The bias was also lowest with Harris-Benedict 1.1 (mean error -9 kcal/day, range +403 to -421 kcal/day); but errors across all equations were clinically unacceptable.

CONCLUSIONS

No equation accurately predicted REE in most hospitalized patients. Without a reliable predictive equation, only indirect calorimetry will provide accurate assessment of energy needs. Although indirect calorimetry is considered the standard for assessing REE in hospitalized patients, several predictive equations are commonly used in practice. Their accuracy in hospitalized patients has been questioned. This study evaluated several of these equations, and found that even the most accurate equation (the Harris-Benedict 1.1) was inaccurate in 39% of patients and had an unacceptably high error. Without knowing which patient's REE is being accurately predicted, indirect calorimetry may still be necessary in difficult to manage hospitalized patients.

Clinical evaluation of hormonal stress state in medical ICU patients: a prospective blinded observational study

OBJECTIVE

To evaluate whether classification of patients as having low, moderate, or high stress based on clinical parameters is associated with plasma levels of stress hormone.

DESIGN AND SETTING

Prospective, blinded, observational study in an 18-bed medical ICU.

PATIENTS

Eighty-eight consecutive patients.

INTERVENTIONS

Patients were classified as low (n=28), moderate (n=33) or high stress (n=27) on days 0 and 3 of ICU stay, based on 1 point for each abnormal parameter: body temperature, heart rate, systemic arterial pressure, respiratory rate, physical agitation, presence of infection and catecholamine administration. The stress categories were: high: 4 points or more, moderate 2-3 points, low 1 point. Plasma growth hormone (GH), insulin-like growth factor 1 (IGF-1), insulin, glucagon, cortisol were measured on days 0 and 3.

MEASUREMENTS AND RESULTS

Plasma cortisol and glucagon were significantly higher and IGF-1 lower in high vs. low stress patients on days 0 and 3. High stress patients were more likely to have high cortisol levels (odds ratio 5.8, confidence interval 1.8-18.9), high glucagon (8.7, 2.1-36.1), and low IGF-1 levels (5.9, 1.8-19.0) than low stress patients on day 0. Moderate stress patients were also more likely to have high cortisol and glucagon levels than low stress patients. Insulin and GH did not differ significantly. Results were similar for day 3.

CONCLUSIONS

Moderate and severe stress was significantly associated with high catabolic (cortisol, glucagon) and low anabolic (IGF-1) hormone levels. The hormonal stress level in ICU patients can be estimated from simple clinical parameters during routine clinical evaluation.

Has the pendulum swung too far in postoperative pain control?

BACKGROUND

The Joint Commission on Accreditation of Health Care Organizations declared pain level to be the "fifth vital sign." This has led to increased efforts to reduce patients' pain scores. Current postoperative analgesic modalities may not be entirely safe. We prospectively studied pain and sedation scores to determine whether postoperative patients were reaching sedation levels similar to patients undergoing "conscious sedation" (eg, colonoscopy cases). "Conscious sedation" patients have been shown to achieve states of sedation, which at time result in oxygen desaturation.

METHODS

Fifty-three patients within three groups were compared in an observational study. Group 1 included "conscious sedation" patients undergoing colonoscopy. Group 2 included postoperative patients using patient-controlled analgesia (PCA). Group 3 included postoperative patients under nurse-controlled analgesia (NCA). Levels of sedation were monitored using the 6-point Ramsay sedation scale. Pain and oxygen saturation were monitored using an 11-point verbal scale and finger pulse oximetry, respectively. Patients were monitored for up to 12 hours in the postoperative period or for the length of their colonoscopy procedure.

RESULTS

Patients in groups 1 and 2 reached similar sedation levels.

CONCLUSIONS

Patients may reach dangerous levels of sedation during the first 24 hours postoperatively. Patients using PCA devices warrant close observation during this time period.