Clinical Outcomes of Acute Respiratory Failure Associated With Noninvasive and Invasive Ventilation in a Pediatric ICU

BACKGROUND

It remains unknown if pediatric patients failing initial noninvasive ventilation (NIV) experience worse clinical outcomes than those successfully treated with NIV or those primarily intubated.

METHODS

This was a single-center, retrospective review of patients admitted with acute respiratory failure to the University of Michigan pediatric intensive care or cardiothoracic ICUs and receiving NIV or invasive mechanical ventilation as first-line therapy.

RESULTS

One hundred seventy subjects met inclusion criteria and were enrolled: 65 NIV success, 55 NIV failure, and 50 invasive mechanical ventilation alone. Of those failing NIV, median time to intubation was 1.8 (interquartile range [IQR] < 1-7) h. On multivariable regression, ICU-free days were significantly different between groups (NIV success: 22.9 ± 6.9 d; NIV failure: 13.0 ± 6.6 d; invasive ventilation: 12.5 ± 6.9 d; P < .001 across all groups). Multivariable regression revealed no difference in ventilator-free days between NIV failure and invasive ventilation groups (15.4 ± 10.1 d vs 15.9 ± 9.7 d, P = .71). Of 64 subjects (37.6%) meeting Pediatric Acute Lung Injury Consensus Conference pediatric ARDS criteria, only 14% were successfully treated with NIV. Ventilator-free days were similar between the NIV failure and invasive ventilation groups (11.6 vs 13.2 d, P = .47). On multivariable analysis, ICU-free days were significantly different across pediatric ARDS groups (P < .001): NIV success: 20.8 + 31.7 d; NIV failure: 8.3 + 23.8 d; invasive alone: 8.9 + 23.9 d, yet no significant difference in ventilator-free days between those with NIV failure versus invasive alone (11.6 vs 13.2 d, P = .47).

CONCLUSIONS

We demonstrated that critically ill pediatric subjects unsuccessfully trialed on NIV did not experience increased ICU length of stay or fewer ventilator-free days when compared to those on invasive mechanical ventilation alone, including in the pediatric ARDS subgroup. Our findings are predicated on a median time to intubation of < 2 h in the NIV failure group and the provision of adequate monitoring while on NIV.

Brainstem hypoxic-ischemic lesions on MRI in infants treated with therapeutic cooling: effects on the length of stay and mortality

OBJECTIVE

To test the hypothesis that brainstem hypoxic-ischemic injury on magnetic resonance imaging (MRI) would be independently associated with short-term outcomes in cooled asphyxiated infants.

METHODS

A total of 90 consecutively cooled asphyxiated infants who survived to have brain MRI were reviewed. A neuroradiologist who was masked to outcomes evaluated MRI images for brainstem involvement. Outcomes were mortality and length of stay.

RESULTS

Brainstem lesions were present on post-cooling brain MRI in 20 of the 90 infants (22%). Overall, four infants died before discharge, and all four had brainstem involvement. The infants with brainstem involvement had longer hospital stay (29 days, IQR 20-47 versus 16 days, IQR 10-26; P = 0.0001), compared to infants without brainstem lesions (n = 70); and upon multivariate analysis, brainstem involvement remained independently associated with prolonged hospital stay (β = 12.4, P = 0.001).

CONCLUSION

This study demonstrates the importance of recognizing brainstem injury for the prediction of short-term outcomes in cooled asphyxiated infants.

Rescue high frequency ventilation for congenital diaphragmatic hernia

INTRODUCTION

High frequency jet (HFJV) and oscillatory (HFOV) ventilation were used to rescue newborns with congenital diaphragmatic hernia (CDH), who failed conventional mechanical ventilation (CV). Changes in ventilator settings and pulmonary gas exchange were evaluated following transition to high frequency ventilation (HFV).

METHODS

Records of patients with CDH rescued with HFV prior to surgical intervention between 2006 and 2015 were reviewed. Mean airway pressure (Pāw) and arterial blood gases during CV and those obtained within the first hour of HFV were compared. A composite repeated measure analysis was performed to evaluate longitudinal and intergroup variances.

RESULTS

Twenty-seven patients were rescued from CV, 16 by HFJV and 11 by HFOV. The two groups had similar gestational ages and birth weights. Prior to HFV, both groups had similar Pāw, PaCO2, FiO2 and PaO2. HFV was associated with a significant improvement in ventilation, and the rate of decrease of PaCO2 was no different between groups. There was a significantly higher increase in Pāw increase with HFOV compared to HFJV.

CONCLUSIONS

In newborns with CDH rescued with HFV, ventilation improved but Pāw was significantly lower in patients supported with HFJV compared to HFOV.

Determining the Accuracy and Reliability of Indirect Calorimeters Utilizing the Methanol Combustion Technique

BACKGROUND

Several indirect calorimetry (IC) instruments are commercially available, but comparative validity and reliability data are lacking. Existing data are limited by inconsistencies in protocols, subject characteristics, or single-instrument validation comparisons. The aim of this study was to compare accuracy and reliability of metabolic carts using methanol combustion as the cross-laboratory criterion.

METHODS

Eight 20-minute methanol burn trials were completed on 12 metabolic carts. Respiratory exchange ratio (RER) and percent O₂ and CO₂ recovery were calculated.

RESULTS

For accuracy, 1 Omnical, Cosmed Quark CPET (Cosmed), and both Parvos (Parvo Medics trueOne 2400) measured all 3 variables within 2% of the true value; both DeltaTracs and the Vmax Encore System (Vmax) showed similar accuracy in measuring 1 or 2, but not all, variables. For reliability, 8 instruments were shown to be reliable, with the 2 Omnicals ranking best (coefficient of variation [CV] < 1.26%). Both Cosmeds, Parvos, DeltaTracs, 1 Jaeger Oxycon Pro (Oxycon), Max-II Metabolic Systems (Max-II), and Vmax were reliable for at least 1 variable (CV ≤ 3%). For multiple regression, humidity and amount of combusted methanol were significant predictors of RER (R² = 0.33, P < .001). Temperature and amount of burned methanol were significant predictors of O₂ recovery (R² = 0.18, P < .001); only humidity was a predictor for CO₂ recovery (R² = 0.15, P < .001).

CONCLUSIONS

Omnical, Parvo, Cosmed, and DeltaTrac had greater accuracy and reliability. The small number of instruments tested and expected differences in gas calibration variability limits the generalizability of conclusions. Finally, humidity and temperature could be modified in the laboratory to optimize IC conditions.

Does hyperglycemia in hypernatremic preterm infants increase the risk of intraventricular hemorrhage?

OBJECTIVE

Hypernatremia and hyperglycemia are highly prevalent in preterm infants during the first week after birth, and both can lead to hyperosmolarity and osmotic shifts. The objective is to determine whether hyperglycemia increases the risk of intraventricular hemorrhage (IVH) in hypernatremic preterm infants.

STUDY DESIGN

Single-center retrospective medical record review of 216 infants <1000 g birth weight and <29 weeks gestational age (admitted over a 9-year period) who had serum sodium levels and blood glucose levels monitored at least every 24 h and more frequently if indicated during the first 10 days after birth. Hyperglycemia was defined as persistently high blood glucose (usually >200 mg dl(-1)) treated with an insulin infusion. Hypernatremia was defined as a serum sodium level of ⩾150 mmol l(-1) on repeated measurements.

RESULTS

Of the 216 infants studied, 76 (35%) developed hyperglycemia and 126 (58%) developed hypernatremia. IVH developed more frequently in infants with hyperglycemia (P=0.006, odds ratio (OR) 2.3, 95% confidence interval (CI) 1.3 to 4.1), in infants with hypernatremia (P=0.018, OR 2.0, 95% CI 1.2 to 3.5) and in infants with hypernatremia plus hyperglycemia (P=0.001, OR 3.2, 95% CI 1.6 to 6.4). Multivariate regression analysis confirmed the independent association of higher risk of IVH with the presence of hypernatremia plus hyperglycemia (P=0.015, OR 2.6, 95% CI 1.2 to 5.5) but not with hypernatremia or hyperglycemia alone.

CONCLUSION

Hyperglycemia increases the risk of IVH in hypernatremic preterm infants.

Do prenatal steroids improve the survival of late preterm infants with complex congenital heart defects?

AIM

We evaluated the use of prenatal steroids (PNS) and the effect of that practice on hospital mortality of late preterm infants with complex congenital heart defects (CHD).

METHODS

Retrospective review of records of late preterm infants with complex CHD infants that were cared for in a single tertiary perinatal center between 2002 and 2009. Multivariate logistic regression analysis was performed to determine which of the risk factors commonly associated with death prior to discharge from the hospital predict the outcome (hospital death).

RESULTS

Of the 106 late preterm infants with complex CHD, 31(29%) died and 15 (14%) received PNS. Endotracheal intubation in the delivery room (42% vs 15%), necrotizing enterocolitis (10% vs 0%) and hypoplastic left heart syndrome (52% vs 25%) were statistically more frequent in non-surviving infants. Non-surviving infants were more frequently treated with PNS (23% vs 11%) but this difference was not statistically significant (p = 0.131). Using logistic regression analysis, delivery room intubation (OR 4.91; 95% CI 1.78 - 13.51) and the hypoplastic left heart syndrome (OR 3.29; 95% CI 1.28 - 8.48), but not prenatal steroids were independently associated with increased risk of hospital death.

CONCLUSIONS

In a selected population of late preterm infants with complex CHD, prenatal steroid treatment did not independently influence survival.

Assessment of association between rapid fluctuations in serum sodium and intraventricular hemorrhage in hypernatremic preterm infants

AIM

This study aims to determine the association between the rapid fluctuations in serum sodium and intraventricular hemorrhage (IVH) or death in hypernatremic preterm infants.

STUDY DESIGN

Single center observational study including 216 infants < 1,000 g birth weight and <29 weeks gestational age, who had serum sodium levels monitored at least every 12 hours. Logistic regression analyses were used to identify which of the commonly cited risk factors for IVH, including the rapid (to the extent of ≥10 and ≥15 mmol/L/d) rise or fall in serum sodium, was associated with the primary outcome of any IVH, or the secondary composite outcome of severe IVH or death during the first 10 days of life in hypernatremic infants.

RESULTS

Of 216 infants, 126 (58%) studied developed hypernatremia (serum sodium ≥ 150 mmol/L). IVH was more frequent in hypernatremic infants (p = 0.01). Presence of hypernatremia was an independent risk factor for IVH on logistic regression analysis (p = 0.022, odds ratio 2.0, 95% confidence interval: 1.1-3.8). Rapid (≥ 10 and ≥ 15 mmol/L/d) rise or fall in serum sodium in hypernatremic infants was not associated with the outcomes.

CONCLUSION

Hypernatremia per se, but not the rapid fluctuations (not exceeding 10-15 mmol/L/d) in serum sodium was independently associated with IVH.

Evaluation of the oxygenation index in adult respiratory failure

BACKGROUND

The oxygenation index (mean airway pressure × FIO2 divided by PaO2) was originally devised to measure severity of illness and predict outcome in neonatal respiratory failure. We evaluated the discrimination of a modified oxygenation index (modified with age) for predicting 28-day mortality in adults with respiratory failure (adult respiratory distress syndrome [ARDS]) using the ALVEOLI section of the ARDSNet database and validated the results in the full ARDSNet database.

METHODS

We compared age-adjusted oxygenation index (AOI) on ventilator Days 1 to 4 with 28-day mortality.

RESULTS

AOI correlated positively with mortality (area under the receiver operating characteristic curve, 0.70-0.74, for ARDS Days 1-4). Following initial development, AOI related to mortality was validated in two other ARDSNet databases producing similar results (area under the receiver operating characteristic curve, 0.70-0.78).

CONCLUSION

The observed sensitivity and specificity analysis demonstrated that AOI is equivalent to or better than other mortality prediction systems used for ARDS.

LEVEL OF EVIDENCE

Prognostic, level III.

Validation of the V(max) metabolic cart in a simulated pediatric model

BACKGROUND

The ability to accurately measure resting energy expenditure (REE) using indirect calorimetry, often referred to as the "gold standard" in nutrition needs assessment, is important given the well-established positive correlation between patient outcome and proportion of the nutrition goal met. While many studies have been done to compare various metabolic carts with one another, the literature lacks a large simulator-based validation of any metabolic cart system.

MATERIALS AND METHODS

In the present study, 8 specifically trained staff members independently conducted 10 simulation trials each using the V(max) Encore metabolic analyzer in conjunction with a metabolic calibration system, which simulates patient metabolic activity, to validate the accuracy of the V(max) Encore across a wide range of simulated metabolic conditions. Testing conditions consisted of incremental adjustments in calibrated gas infusion with a consistently set tidal volume and respiratory rate.

RESULTS

There was a strong, statistically significant correlation between the predicted and actual VO2 and VCO2 data (VO2, R (2) = 0.998; VCO2, R (2) = 0.997). In addition, we observed no significant difference between individuals performing these trials (VO2, P = 1.000, F = 0.021, df = 79; VCO2, P = 1.000, F = 0.030, df = 79).

CONCLUSIONS

This study is the first to report on such a wide spectrum of metabolic activity (50-2000 kcal REE) using a calibrated bench model and validates the accuracy, reproducibility, and use of the V(max) Encore metabolic cart.

Relationship between acute kidney injury and brain MRI findings in asphyxiated newborns after therapeutic hypothermia

BACKGROUND

We hypothesized that acute kidney injury (AKI) in asphyxiated neonates treated with therapeutic hypothermia would be associated with hypoxic-ischemic lesions on brain magnetic resonance imaging (MRI).

METHODS

Medical records of 88 cooled neonates who had had brain MRI were reviewed. All neonates had serum creatinine assessed before the start of cooling; at 24, 48, and 72 h through cooling; and then on day 5 or 7 of life. A neonatal modification of the Kidney Disease: Improving Global Outcomes guidelines was used to classify AKI. MRI images were evaluated by a neuroradiologist masked to outcomes. Outcome of interest was abnormal brain MRI at 7-10 d of life.

RESULTS

AKI was found in 34 (39%) of 88 neonates, with 15, 7, and 12 fulfilling criteria for stages 1, 2, and 3, respectively. Brain MRI abnormalities related to hypoxia-ischemia were present in 50 (59%) newborns. Abnormal MRI was more frequent in infants from the AKI group (AKI: 25 of 34, 73% vs. no AKI: 25 of 54, 46%; P = 0.012; odds ratio (OR) = 3.2; 95% confidence interval (CI) = 1.3-8.2). Multivariate analysis identified AKI (OR = 2.9; 95% CI = 1.1-7.6) to be independently associated with the primary outcome.

CONCLUSION

AKI is independently associated with the presence of hypoxic-ischemic lesions on postcooling brain MRI.

Current knowledge of acute lung injury and acute respiratory distress syndrome

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) continues to be a major cause of mortality in adult and pediatric critical care medicine. This article discusses the pulmonary sequelae associated with ALI and ARDS, the support of ARDS with mechanical ventilation, available adjunctive therapies, and experimental therapies currently being tested. It is hoped that further understanding of the fundamental biology, improved identification of the patient's inflammatory state, and application of therapies directed at multiple sites of action may ultimately prove beneficial for patients suffering from ALI/ARDS.

Esophageal and rectal temperatures as estimates of core temperature during therapeutic whole-body hypothermia

We monitored whole-body cooling concurrently by both esophageal and rectal probes. Esophageal temperature was significantly higher compared with simultaneous rectal temperature during cooling, with a temperature gradient ranging from 0.46 to 1.03°C (median, 0.8°C; IQR, 0.6-0.8°C). During rewarming, this temperature difference disappeared.

The effect of late preterm birth on mortality of infants with hypoplastic left heart syndrome

OBJECTIVES

We evaluated the effect of late preterm (34 to 36 weeks' gestation) delivery on hospital mortality of infants with hypoplastic left heart syndrome (HLHS).

STUDY DESIGN

Retrospective review of records of infants born at or after 34 weeks with no other lethal anomalies, cared for in a single tertiary perinatal center between 2002 and 2009. Factors associated with death prior to discharge from the hospital were ascertained using univariate and multivariate analyses.

RESULTS

Of the 243 infants with HLHS, 35 were late preterm and 208 were ≥37 weeks (term). Using logistic regression analysis, late preterm delivery (odds ratio [OR] 2.95; 95% confidence interval [CI] 1.35 to 6.45), the presence of other major cardiac defects (OR 3.76; 95% CI 1.31 to 10.81), and the presence of noncardiac congenital anomalies (OR 6.13; 95% CI 1.43 to 26.22) were independently associated with hospital death.

CONCLUSION

Late preterm birth of infants with HLHS was independently associated with an increased risk of hospital death compared with those delivered at term.

Does phenobarbital improve the effectiveness of therapeutic hypothermia in infants with hypoxic-ischemic encephalopathy?

OBJECTIVE

To determine whether phenobarbital (PB) given before therapeutic hypothermia to infants with hypoxic-ischemic encephalopathy (HIE) augments the neuroprotective efficacy of hypothermia.

STUDY DESIGN

Records of 68 asphyxiated infants of 36 weeks' gestation, who received hypothermia for moderate or severe HIE were reviewed. Some of these infants received PB prophylactically or for clinical seizures. All surviving infants had later brain magnetic resonance imaging (MRI). The composite primary outcome of neonatal death related to HIE with worsening multiorgan dysfunction despite maximal treatment, and the presence of post-hypothermia brain MRI abnormalities consistent with hypoxic-ischemic brain injury, were compared between the infants who received PB before initiation of hypothermia (PB group, n=36) and the infants who did not receive PB before or during hypothermia (No PB group, n=32). Forward logistic regression analysis determined which of the pre-hypothermia clinical and laboratory variables predict the primary outcome.

RESULT

The two groups were similar for severity of asphyxia as assessed by Apgar scores, initial blood pH and base deficit, early neurologic examination, and presence of an intrapartum sentinel event. The composite primary outcome was more frequent in infants from the PB group (PB 78% versus No PB 44%, P=0.006, odds ratio 4.5, 95% confidence interval 1.6 to 12.8). Multivariate analysis identified only the PB receipt before initiation of hypothermia (P=0.002, odds ratio 9.5, 95% confidence interval 2.3 to 39.5), and placental abruption to be independently associated with a worse primary outcome.

CONCLUSION

PB treatment before cooling did not improve the composite outcome of neonatal death or the presence of an abnormal post-hypothermia brain MRI, but the long-term outcomes have not yet been evaluated.

The effect of late preterm birth on mortality of infants with major congenital heart defects

OBJECTIVE

We evaluated the effect of late preterm delivery (34 to 36 weeks) on hospital mortality of infants with congenital heart defects (CHDs).

STUDY DESIGN

Retrospective record review of infants with major CHD born at or after to 34 weeks, cared for in a single tertiary perinatal center between 2002 and 2009. Factors associated with death before discharge from the hospital were ascertained using univariate and multivariate analyses.

RESULT

Of the 753 infants with CHD, 117 were born at late preterm. Using logistic regression analysis, white race (OR; 95% CI) (0.60; 0.39 to 0.95), late preterm delivery (2.70; 1.69 to 4.33), and need for intubation in the delivery room (3.15; 1.92 to 5.17) were independently associated with hospital death.

CONCLUSION

Late preterm birth of infants with major CHDs was independently associated with increased risk of hospital death compared with delivery at more mature gestational ages.

Nutrition in critical care

Critical care has evolved from a prolonged recovery room stay for cardiac surgery patients to a full medical and nursing specialty in the last 5 decades. The ability to feed patients who cannot eat has evolved from impossible to routine clinical practice in the last 4 decades. Nutrition in critically ill patients based on measurement of metabolism has evolved from a research activity to clinical practice in the last 3 decades. The authors have been involved in this evolution and this article discusses past, present, and likely future practices in nutrition in critically ill patients.

Rebound in ventilator-associated pneumonia rates during a prevention checklist washout period

OBJECTIVE To describe the washout effect after stopping a prevention checklist for ventilator-associated pneumonia (VAP). METHODS VAP rates were prospectively monitored for special cause variation over 42&emsp14;months in a paediatric intensive care unit. A VAP prevention bundle was implemented, consisting of head of bed elevation, oral care, suctioning device management, ventilator tubing care, and standard infection control precautions. Key practices of the bundle were implemented with a checklist and subsequently incorporated into the nursing and respiratory care bedside flow sheets to achieve long-term sustainability. Compliance with the VAP bundle was monitored throughout. The timeline for the project was retrospectively categorised into the benchmark phase, the checklist phase (implementation), the checklist washout phase, and the flowsheet phase (cues in the flowsheet). RESULTS During the checklist phase (12&emsp14;months), VAP bundle compliance rose from <50% to >75% and the VAP rate fell from 4.2 to 0.7 infections per 1000 ventilator days (p<0.059). Unsolicited qualitative feedback from frontline staff described overburdensome documentation requirements, form fatigue, and checklist burnout. During the checklist washout phase (4&emsp14;months), VAP rates rose to 4.8 infections per 1000 ventilator days (p<0.042). In the flowsheet phase, the VAP rate dropped to 0.8 infections per 1000 ventilator days (p<0.047). CONCLUSIONS Salient cues to drive provider behaviour towards best practice are helpful to sustain process improvement, and cessation of such cues should be approached warily. Initial education, year-long habit formation, and effective early implementation demonstrated no appreciable effect on the VAP rate during the checklist washout period.

Predicting death despite therapeutic hypothermia in infants with hypoxic-ischaemic encephalopathy

OBJECTIVE

To determine precooling attributes possibly predicting death in infants with hypoxic-ischaemic encephalopathy (HIE) despite therapeutic cooling.

METHODS

Eighty-five consecutive infants of ≥36 weeks' gestation who received cooling for HIE were reviewed. Logistic regression analysis was performed using precooling clinical and laboratory variables with death related to HIE during the first 9 months of life as the primary outcome.

RESULTS

Thirteen (15%) of the 85 infants died during 9-18 months of follow-up despite cooling. 27 of the 85 were asystolic at birth but only 12 had Apgar scores of zero at both 5 and 10 min. Univariate analysis identified Apgar scores of zero at 5 and 10 min, pH <6.7, base deficit >22 mmol/l, and absent spontaneous movement as significantly associated with death during the first 9 months despite cooling. On multivariate analysis, only the Apgar score of zero at 10 min (p<0.001, OR 51.7, 95% CI 9.9 to 269.5) remained significantly associated with the primary outcome of death from HIE. Of the 12 infants who were asystolic at and beyond 10 min of life, nine died from HIE, two had spastic quadriparesis and global delay at 18-24 months, and one had extensive encephalomalacia on brain MRI during follow-up.

CONCLUSIONS

Of the selected precooling variables, only the 10 min Apgar score is independently associated with death despite therapeutic cooling in infants with HIE. Infants who remain asystolic at 10 min and beyond are unlikely to survive despite cooling, and the rare survivor is likely to have severe disability.

Review of A Large Clinical Series: Association of Cumulative Fluid Balance on Outcome in Acute Lung Injury: A Retrospective Review of the ARDSnet Tidal Volume Study Cohort

Objective: To evaluate the independent influence of fluid balance on outcomes for patients with acute lung injury. Design: Secondary analysis of a prospective cohort study conducted between March 1996 and March 1999. Setting: The study involved 10 academic clinical centers (with 24 hospitals and 75 Intensive Care Units). Patients: All patients for whom fluid balance data existed (844) from the 902 patients enrolled in the National Heart Lung Blood Institute's ARDS Network ventilator-tidal volume trial. Interventions: The study had no interventions. Measurements/Results: On the first day of study enrollment, 683 patients were, on average, more than 3.5 L in positive fluid balance compared to 161 patients in negative fluid balance (P < .001). Cumulative negative fluid balance on day 4 of the study was associated with an independently lower hospital mortality (OR, 0.50; 95% CI, 0.28-0.89; P < .001) more ventilator and intensive care unit—free days. Conclusions: Negative cumulative fluid balance at day 4 of acute lung injury is associated with significantly lower mortality, independent of other measures of severity of illness.

Going back for more: an evaluation of clinical outcomes and characteristics of readmissions to a pediatric intensive care unit

OBJECTIVE

To determine mortality, length of stay, and factors associated with readmissions to the pediatric intensive care unit (PICU).

DESIGN

A retrospective analysis of prospectively collected data.

SETTING

A 16-bed medical-surgical tertiary PICU and a coexisting 15-bed pediatric cardiac intensive care unit.

PATIENTS

All admissions from July 1, 1998, through June 30, 2004.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Of 8,885 total eligible admissions, 711 (8%) were readmissions to the PICU. The median age of the overall cohort was 35.2 months (interquartile range, 5.5-128.2). Readmitted patients were younger (10.4 vs. 37.7 months, p < .01), had greater severity of illness (p < .01), and were more likely to be admitted emergently (p < .01), in comparison with single admissions. In multivariate analyses, readmitted patients had a trend toward higher odds of mortality (odds ratio, 1.39; 95% confidence interval, 0.98-1.98) and stayed 2.96 days longer in the PICU (95% confidence interval, 1.98-3.94) compared with single admissions to the PICU. Factors independently associated with PICU readmission were infant age (odds ratio, 1.98; 95% confidence interval, 1.57-2.49), emergent admission (odds ratio, 2.21; 95% confidence interval, 1.78-2.77), illness severity (odds ratio, 1.03; 95% confidence interval, 1.01-1.04), and time of the year between July and September (odds ratio, 1.52; 95% confidence interval, 1.20-1.93). A diagnosis of trauma was associated with low likelihood of PICU readmission (odds ratio, 0.30; 95% confidence interval, 0.18-0.50).

CONCLUSIONS

Patients readmitted to the PICU during the same hospitalization have significantly adverse outcomes. The study highlights important factors associated with PICU readmissions that can be incorporated into efforts to reduce mortality and resource utilization associated with readmission of critically ill children.

Characteristics and outcomes of interhospital transfers from level II to level I pediatric intensive care units

OBJECTIVE

To examine the characteristics, resource utilization, and outcomes for transfer admissions from level II to level I pediatric intensive care units (PICUs).

DESIGN

Retrospective study.

SETTING

A 16-bed level I PICU in a tertiary care children's hospital.

PATIENTS

All transfer admissions from level II PICUs from January 1, 1997, through December 31, 2003; admissions for cardiac surgery were excluded. Patient characteristics, resource utilization, and outcomes were described and then compared across predefined strata (low <5%, moderate 5-30%, and high >30%) of predicted probability of death.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 168 transfer admissions, 45%, 30%, and 25% were in the low, moderate, and high mortality risk groups, respectively. Length of stay at the referring PICU was shortest for the high-risk admissions. The most frequent diagnoses among all risk groups were respiratory failure (49%) and sepsis (14%). High-risk admissions were more likely to receive advanced therapies such as extracorporeal membrane oxygenation (41.5% high risk vs. 39.2% moderate vs. 6.6% low risk, p < .01) and renal replacement therapy (34.2% vs. 17.7% vs. 2.6%, p < .01). The high-risk admissions had longer PICU length of stay and the highest death rates (34% vs. 10% vs. 4%, p < .01) when compared with the moderate- and low-risk admissions, respectively.

CONCLUSIONS

This study highlights significant differences in patient characteristics, resource utilization, and outcomes across mortality risk-stratified groups of critically ill and injured children transferred from level II to level I PICU care. Further studies are warranted to investigate decision making that prompt inter-PICU transfers.

Hospital readmission for bronchiolitis

The objectives of this study were to determine the rate and risk factors for hospital readmission after inpatient treatment for bronchiolitis. We conducted a retrospective cohort study from 2000 to 2002. The readmission rate within 30 days was 3.7% (95% Confidence Interval: 2.1%-6.0%). Readmission was not associated with age, prematurity, respiratory syncytial virus status, receipt of intensive care, or the observation period off supplemental oxygen. Those who required supplemental oxygen had a lower risk of readmission. Identifying children at risk for readmission is challenging. Children who did not require supplemental oxygen may be at greater risk because they are progressing in their illness.

Immediate changes in lung compliance following natural surfactant administration in premature infants with respiratory distress syndrome: a controlled trial

OBJECTIVE

To compare immediate changes in lung compliance following the administration of two commercially available natural surfactants.

METHOD

We conducted a prospective, randomized study of 40 preterm infants with respiratory distress syndrome requiring surfactant. Infants received either Infasurf or Survanta. The primary outcome measure was the change in compliance assessed by bedside pulmonary monitoring.

RESULTS

There were no significant changes in dynamic lung compliance within or between the two groups 1 hour after surfactant administration. However, infants given Survanta required more doses per patient (4 vs 2, p=0.05) and were more likely to require >2 doses (57 vs 26%, p=0.05). Infants requiring >1 dose of surfactant had a greater change in airway pressure and improved oxygenation just before the second dose when treated with Infasurf.

CONCLUSIONS

We found no significant difference in acute changes in lung compliance. However, treatment with Infasurf seems to be more long lasting than Survanta.

Continuous quality improvement: reducing unplanned extubations in a pediatric intensive care unit

OBJECTIVE

Unplanned extubation (UEX) is a potentially serious complication of mechanical ventilation. Limited information is available regarding factors that contribute to UEXs and subsequent reintubation of children. We monitored UEXs in our pediatric intensive care unit (PICU) for a 5-year period to assess the incidence and patient conditions associated with UEX and to evaluate whether targeted interventions were associated with a reduced rate of UEXs.

METHODS

Over a 5-year period, demographic and clinical information was collected prospectively on all patients who required an artificial airway while admitted to the PICU. Additional information was collected for patients who experienced an UEX. Educational sessions and care management protocols were developed, implemented, and modified according to issues identified via the monitoring program.

RESULTS

From a total of 2192 patients who required 13 630 airway days (AWD), 141 (6%) patients experienced 164 UEXs. The overall rate of UEX for the study period was 1.2 UEXs per 100 AWD, and this rate decreased from 1.5 in the first year to 0.8 in the last year. UEXs were more common in children who were younger than 5 years (1.6 vs 0.6 UEX per 100 AWD) compared with older children. The UEX children experienced significantly longer length of mechanical ventilation (6 vs 3 days) and longer length of PICU stay (8 vs 4 days) compared with non-UEX children. Forty-six percent of the UEXs occurred in patients who were weaning from mechanical ventilation, and 22% of those patients required reintubation.

CONCLUSIONS

We conclude that UEX in pediatric patients is associated with longer length of mechanical ventilation and length of stay in the PICU. A continuous quality improvement monitoring and educational program that identified high-risk patients for UEX (younger patients) and patients who were at low risk for subsequent reintubation (weaning patients) contributed to a reduction of these potentially adverse events.

Nosocomial catheter-related bloodstream infections in a pediatric intensive care unit: risk and rates associated with various intravascular technologies

OBJECTIVE

Nosocomial bloodstream infections are associated with increased patient morbidity, mortality, and hospital costs. More than 90% of these infections are related to the use of intravascular catheter devices. This study was done to assess the risk and rates of catheter related-bloodstream infections (CR-BSI) associated with different intravascular technologies in a pediatric intensive care unit population.

DESIGN

Retrospective cohort study.

SETTING

A 16-bed pediatric intensive care unit in a tertiary children's hospital.

STUDY POPULATION

All admissions between July 1997 and December 1999 requiring placement of an intravascular access device for care were examined. Patients with CR-BSI were identified through ongoing surveillance using Centers for Disease Control/National Nosocomial Infections Surveillance System definitions for bloodstream infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 2,728 admissions during the review period, 1,043 (38.3%) required placement of an intravascular access device. Bivariate analysis revealed that patients who required intravascular cannulae for extracorporeal life support had a 10-fold increased risk of developing a CR-BSI, and patients requiring vascular access for renal replacement therapy demonstrated a 4-fold increase in the risk of developing CR-BSI compared with the referent group. There was a significant increase in the CR-BSI rate associated with the use of more intravascular access devices per patient admission. Multivariate logistic regression identified the use of extracorporeal life support therapy and the total duration of use of intravascular access devices as significant independent predictors of CR-BSI when controlling for other predictors.

CONCLUSION

The use of extracorporeal life support therapy, the presence of multiple intravascular access devices, and the total duration of intravascular access device use were associated with an increase in the rate and risk of developing CR-BSI in our pediatric intensive care unit population. Larger, prospective studies may help elucidate additional factors responsible for these observations.

The pathophysiology of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a heterogeneous process that results in diffuse alveolar damage. It is associated with a variety of causative factors that can be grouped into two general categories, those associated with direct lung injury through the airways and those associated with indirect lung injury through the blood stream. Regardless of whether injury originates within or outside the lung, a systematic inflammatory response is triggered. This article reviews some of the physiologic alterations associated with ARDS before focusing on the derangement in the cellular environment.

Relationship of neonatal endotracheal tube size and airway resistance

BACKGROUND

Infants receiving mechanical ventilation require narrow-lumen, small-diameter endotracheal tubes.

OBJECTIVE

Compare the resistances of endotracheal tubes used in the neonatal intensive care unit.

METHODS

Endotracheal tubes of internal diameter 2.5, 3.0, 3.5, and 4.0 mm were tested with a standard neonatal ventilator and a test lung. An endotracheal tube of each diameter was cut to 12 cm and connected to a flow transducer at one end and the test lung at the other. Serial measurements of resistance were made at various flows (6, 8, 10, and 12 L/min) and ventilator rates (30-90 breaths/min) encompassing the ranges of clinical practice. Analysis of variance was performed for each tube size, comparing resistance to flows and ventilator rates.

RESULTS

Resistance was significantly higher with the 2.5 mm tube than with the others. There was also a consistent trend, in all the tube sizes, towards higher resistance as flow was increased.

CONCLUSIONS

The higher resistance of the 2.5 mm tube may be detrimental to extremely low birthweight infants kept on mechanical support merely "to grow." The higher resistance may increase the work of breathing and thus increase caloric expenditure and impede growth.

Carotenoids and antioxidant vitamins in patients after burn injury

Oxidative stress may contribute to secondary tissue damage and impaired immune function in patients after burn injury. The purpose of our study was to describe plasma antioxidant micronutrient concentrations in 26 adult patients admitted with extensive burn injuries (> 20 % total burn surface area) to a level-1 trauma burn center during a 21-day period after admission. The effect of administering beta-carotene was also examined with use of a prospective randomized subjects design: patients received either placebo or 30 mg/day in an enteral feeding. Plasma concentrations of alpha- and gamma-tocopherol, carotenoids (alpha and beta-carotene, lycopene, beta-cryptoxanthin, lutein), and retinol were measured with high- performance liquid chromatography, and vitamin C was quantified with spectrophotometry, at baseline and twice per week. Vitamin C, tocopherol, and retinol concentrations were low at baseline, but levels increased significantly over the study period in both groups (p < 0.05). Plasma beta-carotene concentration increased when this carotenoid was provided in the oral feeding. Otherwise, plasma carotenoid concentrations were low at baseline and remained low throughout the study period despite normalization of associated lipids.

The effect of pre-ECLS ventilation time on survival and respiratory morbidity in the neonatal population

Although mechanical ventilation for more than 7 to 10 days has been considered a contraindication to the application of extracorporeal life support (ECLS) in neonates, the outcome and respiratory morbidity for newborns placed on ECLS after more than 7 days of ventilation have not been well characterized. The purpose of this study was to determine the impact of pre-ECLS ventilation time on the rate of survival, the likelihood of the development of bronchopulmonary dysplasia (BPD), and the need for supplemental oxygen at the time of discharge. Examination of the Extracorporeal Life Support Organization (ELSO) Registry showed that 6,110 neonates were treated for respiratory failure with a pre-ECLS ventilation time of less than 14 days between January 1990 and May 1995. Gestational age (GA), birth weight (BW), indication for ECLS, and diagnosis were compared with the rate of survival, the discharge diagnosis of BPD, and the need for home oxygen. The GA and BW of neonates placed on ECLS during the first week of life (n = 5,888) did not differ significantly from those of neonates whose ECLS was begun in the second week of life (n = 222). The neonates were divided into two groups (early, ventilation time of 3 to 6 days; late, ventilation time of 7 to 10 days) to determine the odds ratios for survival, BPD, and home oxygen. Logistic regression analysis was used to develop a model to predict the rate of survival, the risk for the development of BPD, and the need for home oxygen given the length of pre-ECLS ventilation time. The late group was less likely to survive (odds ratio, 1.8; 95% confidence interval [CI], 1.21 to 2.68). The late group also had approximately twice the risk for the development of BPD (odds ratio, 1.9; 95% CI, 1.2 to 3.04) and a trend toward an increased incidence of home oxygen use (odds ratio, 1.55; 95% CI, 0.92 to 2.60). The authors conclude that (1) there is a greater risk of mortality and BPD and a trend toward an increased need for home oxygen with increased time on the ventilator before ECLS; (2) at 14 days the predicted probability of survival is still 53% (95% CI, 31% to 74%); (3) at 14 days the predicted probability of BPD is 54% (95% CI, 28% to 78%); and (4) based on these data, it is reasonable to consider application of ECLS to patients who have had mechanical ventilation for up to 14 days.

A matched pairs analysis of venoarterial and venovenous extracorporeal life support in neonatal respiratory failure

It has been suggested that venovenous (VV) extracorporeal life support (ECLS) confers a survival advantage over venoarterial (VA) ECLS. These results have been confounded by differences in patient populations. In this study, a matched pairs comparison of survival and complication rates in neonatal respiratory failure patients managed with VA or VV ECLS was performed. Retrospective matching of 643 VA and VV patient pairs from the Extracorporeal Life Support Organization Registry was performed. Pairs were matched by same year, same diagnosis, gestational age +/- 1 week, birth weight +/- 0.3 kg, and oxygenation index +/- 5. Further matching for hemodynamic status was possible for 272 pairs and included pre ECLS CPR, use of epinephrine, and arterial pH +/- 0.1. Statistical significance was defined for outcome and selected complication rates using McNemar's chi-square analysis with correction for multiple comparisons. A survival advantage for VV was significant when matching for respiratory failure (83.8% VA versus 91.5% VV), but was not significant when matching for hemodynamic failure (90.4% VA versus 94.5% VV). In the latter match, hemolysis (10.7% VA versus 23.5% VV) and cannula kinking (0.4% VA versus 10.6% VV) were more common with VV ECLS. The incidence of intracranial hemorrhage did not significantly differ between groups (6.3% VA versus 7.4% VV). Survival is not significantly greater with VV ECLS when patients are matched for degree of respiratory and hemodynamic failure. Hemolysis and cannula kinking are more common with VV ECLS. There is no identified difference in the incidence of intracranial hemorrhage.

Comparative evaluation of the hemodynamic effects of oral cimetidine, ranitidine, and famotidine as determined by echocardiography

STUDY OBJECTIVE

To evaluate the influence of cimetidine, ranitidine, famotidine, and placebo on cardiac performance as determined by echocardiography.

DESIGN

Randomized, four-way crossover trial.

SETTING

Echocardiography laboratory at a university hospital.

PARTICIPANTS

Twelve healthy volunteers.

INTERVENTIONS

Volunteers received oral treatment with placebo, cimetidine 800 mg, ranitidine 300 mg, or famotidine 40 mg once/day for 7 days.

MEASUREMENTS AND MAIN RESULTS

On the seventh day of each study phase, 2 hours after administration of the final dose, each subject underwent cardiac echocardiography and Doppler flow studies. No significant differences were detected in ejection fraction, peak flow velocity, or percentage fractional shortening among the treatment phases. A large degree of variability in ejection fraction was observed, with some subjects experiencing marked decreases.

CONCLUSION

The histamine-2 (H2)-receptor antagonists had no effect on the hemodynamic variables as determined by echocardiography. The variability in the hemodynamic response may in part explain the conflicting results reported in the literature. It also raises the question as to whether certain individuals are more sensitive to the potential cardiac effects of H2-receptor antagonists.

Geriatric trauma: aggressive intensive care unit management is justified

The United States population older than 65 years increased 21 per cent from 1980 to 1990. Attempts to characterize geriatric trauma have failed to yield a consensus on basic descriptors or physiologic parameters predictive of outcome. We reviewed the records of 170 trauma patients, aged 60 or above, admitted to our institution in a recent 50-month period. Mortality was 21.8 per cent. None of the 54 general care patients died; 79 (68%) of the 116 ICU patients survived. ICU deaths correlated with number of organ systems failing and severe head injury. Although these results justify aggressive ICU treatment, average hospital stay was 15 days, and one third of patients required skilled nursing facilities for ultimate recovery, so the resource cost is high.

Changes in resting energy expenditure and body composition in anorexia nervosa patients during refeeding

Accurate prediction of the energy level necessary to promote weight restoration in patients with anorexia nervosa would be clinically useful. Resting energy expenditure (REE), respiratory quotient, and body composition were measured in 10 nonmedicated women with anorexia nervosa during a vigorous refeeding protocol. REE was measured three times per week by open-circuit indirect calorimetry after an overnight fast. Subjects ranged in age from 19 to 38 years and weighed 39.9 +/- 4.3 kg (mean +/- standard deviation) at admission. The refeeding protocol was as follows: phase 1, 1,200 kcal/day for 1 week (baseline); phase 2, an increase of 300 kcal/day for 1 week; phase 3, 3,600 kcal/day until target weight was reached; phase 4, 1,800 to 2,800 kcal/day (stabilization). REE was 30.0 +/- 6.4, 33.5 +/- 6.7, 37.3 +/- 6.6 and 34.5 +/- 4.4 kcal/kg body weight during phases 1, 2, 3, and 4, respectively. The Harris-Benedict equation overestimated phase 1 24-hour REE by a mean of 14% and underestimated REE in phases 2, 3, and 4 by a mean of 8%, 24%, and 23%, respectively. Skinfold measurements revealed percent body fat to be 12 +/- 4% at admission and 19 +/- 5% at discharge, with a mean of 48% of the weight gained during refeeding attributable to increased body fat. These findings indicate that refeeding in anorexia nervosa is associated with increased REE, which cannot be explained by increased body mass, and that caloric requirements for weight restoration in patients with anorexia nervosa are best determined by monitoring individual response.

Pneumonia: incidence, risk factors, and outcome in injured patients

One hundred thirty (44.2%) of 294 patients hospitalized for trauma and admitted to the Surgical Intensive Care Unit for mechanical ventilation developed hospital-acquired bacterial pneumonia. The predominant pathogens isolated were gram-negative enteric bacilli (72%), but there was not an increase in mortality associated with gram-negative pneumonia compared with similar patients without pneumonia. Of the seven admission risk factors univariately associated with the development of acquired bacterial pneumonia, only emergent intubation (p less than 0.001), head injury (p less than 0.001), hypotension on admission (p less than 0.001), blunt trauma as the mechanism of injury (p less than 0.001), and Injury Severity Score (p less than 0.001) remained significant after stepwise logistic regression. Not surprisingly, as mechanical ventilation is continued, the probability of pneumonia emerging increases. The consequences of hospital-acquired bacterial pneumonia are a significant seven-, five-, and two-fold increase in mechanically ventilated days, intensive care, and hospital stay, respectively. We conclude that the incidence of hospital-acquired pneumonia in injured patients admitted to the ICU for mechanical ventilation occurs in nearly half the patients, is associated with specific risk factors, and significantly increases morbidity but does not increase mortality.

Evaluation of the Velcom-100 pulse Doppler cardiac output computer

The use of Doppler ultrasound as a means of obtaining cardiac output (CO) measurements quickly, easily, and noninvasively has been made possible by recent technologic developments. We evaluated a new pulse Doppler ultrasonic unit (Velcom-100, Waters Instruments, Inc) in the Surgical Intensive Care Unit at the University of Michigan Medical Center. Accuracy of this device was determined by comparison of CO results obtained from the Velcom-100 (COV) against those of conventional thermal dilution cardiac output (COT) measurements. Twenty-six postoperative patients were used for this study, ranging in age from 20 to 82 years old. Initial studies prior to in vivo standardization demonstrated a significantly lower result (p = 0.039) for the Velcom-100 with a mean difference of 0.86 L/min (COT-COV). This comparison was significantly improved in subsequent studies following in vivo standardization (COT-COV = 0.02 L/min, p = 0.646). Linear regression analysis showed a significant, positive correlation between the two results (r = 0.82, p less than 0.05) indicating an excellent trending capability for the Velcom-100. Our evaluation found the Velcom-100 to be user friendly, allowing rapid training of ICU technicians and applicability for postoperative monitoring.

Measurement of elemental nitrogen by chemiluminescence: an evaluation of the Antek nitrogen analyzer system

Application of indirect calorimetry has aided nutritional support and management in critically ill populations. However, knowledge of resting energy expenditure is only one-half of the nutritional profile. Knowledge of protein losses and requirements are also important. Attainment of positive protein balance is believed to play an important role in wound healing, host defenses, morbidity, and mortality. Previous limitations of the measurement of protein losses (time and cost) have limited its application to the ICU patient. This report describes a relatively new technology which measures elemental nitrogen in biologic samples. We have found this instrument to be fast, accurate, easy to calibrate and use. Its application in the critically ill patient allows us to monitor daily changes in protein losses and balance.

Elevated intracranial pressure associated with hypermetabolism in isolated head trauma

Both metabolic rate and protein catabolism are known to increase following severe head trauma, but the etiology of this hypermetabolism is unknown. To further investigate the problem, we studied the metabolism of 17 patients with indirect calorimetry who had severe craniocerebral trauma only and who required ICP monitoring for management. Patients were studied daily and immediately after ICP spikes greater than 20 mm Hg, prior to treatment with hyperventilation, osmotic diuretics, or barbiturates. Oxygen consumption (VO2) was correlated with ICP. Two groups of patients were identified. Group I patients were treated with hyperventilation and osmotic diuretics while Group II patients additionally received cerebral metabolic depressants. Group I had a significant correlation coefficient between VO2 and ICP. Significant hypercatabolism early in the post trauma period was demonstrated by increased urine urea nitrogen. Our observations suggest that in patients with craniocerebral trauma, elevated ICP is associated with increased oxygen consumption, protein catabolism and systemic hypermetabolism. Cerebral metabolic depressants blunted increases in VO2 which were seen with elevated ICP.

A water-sealed indirect calorimeter for measurement of oxygen consumption (VO2), carbon dioxide production (VCO2), and energy expenditure in infants

We have developed a water-sealed infant calorimeter (IC) system which uses the techniques of closed-circuit spirometry to measure oxygen consumption (VO2) in premature and full-term infants. Carbon dioxide production (VCO2) is simultaneously calculated from the effluent mixed expired CO2 and the circulating flowrate. Respiratory Quotient (RQ) and Energy Expenditure (EE) are then calculated from the primary data. Measurement of VO2, VCO2, and calculation of RQ were +/- 5.0% of predicted values determined by burning ethyl alcohol or volume extraction and CO2 infusion in our bench model. Measurement in 11 premature infants produced mean values for VO2 and VCO2 of 8.5 +/- 2.5 ml/min/kg and 8.5 +/- 2.4 ml/min/kg, respectively. This system is noninvasive, does not interfere with infant tube feedings or iv infusions, and permits safe, long-term monitoring of the infant's metabolic activity. It allows a more exact matching or oral or intravenous feedings to the actual energy expenditure of the infants, and offers potential advantages for the nutritional management of sick infants.

Continuous arteriovenous filtration: an effective treatment for surgical acute renal failure

Continuous arteriovenous hemofiltration (CAVH) is a new method of renal replacement therapy that has several advantages in the surgical treatment of acute renal failure. We initially learned the technique in laboratory testing and then developed a management protocol. Since 1983 we have used CAVH to treat 61 patients with acute renal failure. This extracorporeal technique consists of arteriovenous cannulation of the femoral vessels, which provides continuous blood flow through a hollow-fiber membrane. Hydrostatic pressure (systole greater than 80 mm Hg) creates an ultrafiltrate at a typical rate of 12 L/day. Volume is replaced with an intravenous solution at a rate to achieve the desired fluid balance, usually a net loss of 1 to 2 L/day. This extracellular fluid exchange typically results in removal of 15 gm of urea nitrogen and 50 mEq of potassium per day. The technique can be used in most intensive care units and has relatively few complications. In addition to being a safe and effective means of renal replacement therapy for acute renal failure, CAVH is particularly advantageous for managing conditions of fluid overload in hemodynamically unstable patients.

Suppression of shivering decreases oxygen consumption and improves hemodynamic stability during postoperative rewarming

Thirty-three patients undergoing elective myocardial revascularization were prospectively randomized into two study groups (Group S and Group P) to permit evaluation of the effects of shivering on oxygen consumption per minute (VO2), carbon dioxide production per minute (VCO2), and hemodynamic performance. Group S was allowed to shiver during the postoperative rewarming period, and Group P received hourly injections of pancuronium bromide and Metubine (metocurine) sulfate with sedation to block the shivering response. Group S demonstrated significantly higher increases in VO2 and VCO2, lower systolic blood pressure and mixed venous oxygen saturation, and a greater use of inotropic support than the patients in Group P. Suppression of the shivering response minimized increases in VO2 and VCO2, improved hemodynamic stability, and resulted in a decreased need for inotropic support.

Continuous arteriovenous hemofiltration: improved survival in surgical acute renal failure?

Continuous arteriovenous hemofiltration (CAVH) is an effective method for renal failure management that has the potential to decrease mortality rates. This hypothesis has not been comparatively studied. Fifty six patients with acute oliguric renal failure complicating multiple organ failure had measurements of resting energy expenditure by indirect calorimetry, caloric and protein intake, energy balance, and outcome. Two management protocols included hemodialysis, full calories, and low protein (phase I) or CAVH, full calories, and high protein (phase II). The survival rate in phase I was 12% and 28% in phase II (not a statistically significant difference); CAVH did facilitate parenteral feeding. Patients with positive energy balance had improved survival compared with those with significant energy deficit (37.5% versus 9.4%, p less than 0.025). We conclude that full nutritional support improves survival in acute renal failure. The method of renal replacement therapy is of secondary importance, but CAVH has distinct advantages in the nutritional management of surgical patients.

Metabolic studies in chest trauma

By means of a volumetric respirometer, oxygen consumption and carbon dioxide production were measured in 15 patients with chest trauma who required mechanical ventilation. From the primary measurements, respiratory quotient, daily energy balance, and cumulative energy balance were calculated. There was a moderate increase in metabolic rate, which generally returned to normal during the first week after trauma. A late increase in oxygen consumption was associated with sepsis, large energy deficit, and death in three patients. Carbon dioxide overload caused by excessive feeding caused difficulty in weaning three patients from the ventilator. Measurement of oxygen consumption and carbon dioxide production is helpful in the management of patients with chest trauma and respiratory failure.