Risk Factors for Brain Injury in Newborns Treated with Extracorporeal Membrane Oxygenation.

OBJECTIVE: This study aimed to assess the association of clinical risk factors with severity of magnetic resonance imaging (MRI) brain injury in neonatal extracorporeal membrane oxygenation (ECMO) patients. STUDY DESIGN: This is a single-center retrospective study conducted at an outborn level IV neonatal intensive care unit in a free-standing academic children's hospital. Clinical and MRI data from neonates treated with ECMO between 2005 and 2015 were reviewed. MRI injury was graded by two radiologists according to a modified scoring system that assesses parenchymal injury, extra-axial hemorrhage, and cerebrospinal fluid spaces. MRI severity was classified as none (score = 0), mild/moderate (score = 1-13.5), and severe (score ≥ 14). The relationship between selected risk factors and MRI severity was assessed by Chi-square, analysis of variance, and Kruskal-Wallis tests where appropriate. Combinative predictive ability of significant risk factors was assessed by logistic regression analyses. RESULTS: MRI data were assessed in 81 neonates treated with ECMO. Veno-arterial (VA) patients had more severe injury compared with veno-venous patients. There was a trend toward less severe injury over time. After controlling for covariates, duration of ECMO remained significantly associated with brain injury, and the risk for severe injury was significantly increased in patients on ECMO beyond 210 hours. CONCLUSION: Risk for brain injury is increased with VA ECMO and with longer duration of ECMO. Improvements in care may be leading to decreasing incidence of brain injury in neonatal ECMO patients. KEY POINTS: · Veno-arterial ECMO is associated with more brain injury by MRI compared with veno-venous ECMO.. · Longer duration of ECMO is significantly associated with severe brain injury by MRI.. · Risk for neurologic injury may be decreasing over time with advances in neonatal ECMO..

Postnatal weight gain in preterm infants with severe bronchopulmonary dysplasia.

OBJECTIVES: To characterize postnatal growth failure (PGF), defined as weight < 10th percentile for postmenstrual age (PMA) in preterm (≤ 27 weeks' gestation) infants with severe bronchopulmonary dysplasia (sBPD) at specified time points during hospitalization, and to compare these in subgroups of infants who died/underwent tracheostomy and others. STUDY DESIGN: Retrospective review of data from the multicenter Children's Hospital Neonatal Database (CHND). RESULTS: Our cohort (n = 375) had a mean ± standard deviation gestation of 25 ± 1.2 weeks and birth weight of 744 ± 196 g. At birth, 20% of infants were small for gestational age (SGA); age at referral to the CHND neonatal intensive care unit (NICU) was 46 ± 50 days. PGF rates at admission and at 36, 40, 44, and 48 weeks' PMA were 33, 53, 67, 66, and 79% of infants, respectively. Tube feedings were administered to > 70% and parenteral nutrition to a third of infants between 36 and 44 weeks' PMA. At discharge, 34% of infants required tube feedings and 50% had PGF. A significantly greater (38 versus 17%) proportion of infants who died/underwent tracheostomy (n = 69) were SGA, compared with those who did not (n = 306; p < 0.01). CONCLUSIONS: Infants with sBPD commonly had progressive PGF during their NICU hospitalization. Fetal growth restriction may be a marker of adverse outcomes in this population.

The impact of ethnic population dynamics on neonatal ECMO outcomes: a single urban institutional study.

INTRODUCTION: Neonatal extracorporeal membrane oxygenation ECMO has been clinically used for the last 25 y. It has been an effective tool for both cardiac and non cardiac conditions. The impact of ethno-demographic changes on ECMO outcomes however remains unknown. We evaluated a single institution's experience with non cardiac neonatal ECMO over a 28-y period. METHODS: A retrospective review of all neonates undergoing noncardiac ECMO between the y 1984 and 2011 was conducted and stratified into year groups I, II, III (≤1990, 1991-2000, and ≥2001). Demographic, clinical, and outcome data were collected. The patient specifics, ECMO type, ECMO length, blood use, complications, and outcomes were analyzed. Univariate, bivariate, and multivariate analyses were then performed. RESULTS: Data was available for 827 patients. The number of African-American and Hispanic patients increased over the last 27 y (27.5% versus 45.0% and 3.3% versus 21.5%, year group I versus year group III, respectively). The proportion of congenital diaphragmatic hernia (CDH) patients by ethnicity also increased for African-Americans and Hispanics between the two year groups (22.0% to 33.0% and 4.9% to 33.0%, respectively). Similar pattern was noted for non-CDH diagnoses. Low birth weight, low APGAR scores, CDH, primary pulmonary hypertension, central nervous system hemorrhage, and ECMO were independent predictors of mortality. Ethnicity, in itself however, was not associated with mortality on adjusted analysis. CONCLUSION: More African-Americans and Hispanics have required ECMO over the years with a concurrent decrease in the number of Caucasians. While ethnicity was not an independent predictor of mortality, it appears to be a surrogate for fatal but sometime preventable diagnoses among minorities. Further investigations are needed to better delineate the reason behind this disparity.

A New Approach to Recognize Neonatal Impaired Kidney Function.

INTRODUCTION: Previous studies in term newborns with hypoxic ischemic encephalopathy showed that the rate of serum creatinine (SCr) decline during the first week of life could be used to identify newborns with impaired kidney function (IKF) who are missed by standard definitions of neonatal acute kidney injury (nAKI). METHODS: Retrospective review of the medical records of 329 critically ill newborns ≥27 weeks of gestational age (GA) admitted to a level 4 neonatal intensive care unit (NICU). We tested the hypothesis that the rate of SCr decline combined with SCr thresholds provides a sensitive approach to identify term and preterm newborns with IKF during the first week of life. RESULTS: Excluding neonates with nAKI, an SCr decline <31% by the seventh day of life, combined with an SCr threshold ≥0.7 mg/dl, recognized newborns of 40 to 31 weeks of GA with IKF. An SCr decline <21% combined with an SCr threshold ≥0.8 mg/dl identified newborns of 30 to 27 weeks of GA with IKF. Neonates with IKF (∼17%), like those with nAKI (7%), showed a more prolonged hospital stay and required more days of mechanical ventilation, vasoactive drugs, and diuretics, when compared with the controls. Changes in urine output did not distinguish newborns with IKF. CONCLUSION: The rate of SCr decline combined with SCr thresholds identifies newborns with IKF during the first week of life. This distinctive group of newborns that is missed by standard definitions of nAKI, warrants close monitoring in the NICU to prevent further renal complications.

Reduction in Unintended Extubations in a Level IV Neonatal Intensive Care Unit.

OBJECTIVES: Unintended extubations (UEs) lead to significant morbidity in neonates. A quality improvement project was initiated in response to high rates in our level IV NICU. We targeted creating and sustaining UE rates below the published standard of 1 per 100 ventilator days. METHODS: This project spanned 4 time periods: baseline, epoch 1 (December 2010-May 2012), sustain, and epoch 2 (May 2015-December 2017) by using standard quality improvement methodology. Epoch 1 interventions included real-time analysis of UE events, standardization of taping, patient positioning and movement, accurate event reporting, and change in nomenclature. Epoch 2 interventions included reduction in daily chest radiographs (CXRs) and development of a high-risk tool. Patient and event characteristics were statistically compared across time points. RESULTS: Of the 612 UE events recorded over 10 years, 249 UEs occurred from May 2011 to 2017 involving 184 unique patients. UE rates decreased by 43% (from 1.75 to 0.99 per 100 ventilator days; epoch 1) and were sustained until a notable spike. Epoch 2 interventions led to a further 31% rate reduction. Single CXR use decreased by half. Median corrected gestational age at the time of an event was 35 weeks (interquartile range: 29-41). Seventy percent of infants experiencing an UE required reintubation, 29% had a previous event, and 9% had a code event. CONCLUSIONS: A decrease in UE below benchmarks can be achieved and sustained by standardization and mitigation interventions. This decline was also accompanied by a reduction in use of CXRs without increasing UE events.

Reassessing the need for active surveillance of extended-spectrum beta-lactamase-producing Enterobacteriaceae in the neonatal intensive care population.

OBJECTIVE: To determine the continued need for active surveillance to prevent extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) transmission in a neonatal intensive care unit (NICU). DESIGN: This retrospective observational study included patients with ESBL-E colonization or infection identified during their NICU stay at our institution between 1999 and March 2018. Active surveillance was conducted between 1999 and March 2017 by testing rectal swab specimens collected upon admission and weekly thereafter. The overall incidence rates, of ESBL-E colonization or infection (including hospital acquired) before and after active surveillance were calculated. The cost associated with active surveillance was then estimated. RESULTS: Overall, 171 NICU patients were found to have ESBL-E colonization or infection, and 150 of those patients (87.7%) were detected by active surveillance. The overall incidence rate was 1.4 per 100 patient admissions. The hospital-acquired incidence rate was 0.41 per 1,000 patient days, and this rate had decreased since 2002, with an average of 6 cases detected annually. A significant decrease was observed in 2009 when the unit moved to a new single-bed unit featuring private rooms. Active surveillance was discontinued with no increase in the number of infections. Of the 150 ESBL-E colonized patients, 14 (9.3%) subsequently developed an infection. Active surveillance resulted in a total of 50,950 specimen collections and a cost of $127,187 for processing, an average of $848 to detect 1 ESBL-E colonized patient. CONCLUSION: ESBL-E transmission and infection in our NICU remains uncommon. Active surveillance may have contributed to the decline of ESBL-E transmission when used in conjunction with contact precautions and private rooms, but its relatively high cost could be prohibitive.

Altered cerebrovascular responses after exposure to venoarterial extracorporeal membrane oxygenation: role of the nitric oxide pathway.

BACKGROUND: Previous studies in our laboratory on newborn lambs have shown cerebral autoregulation impairment after exposure to venoarterial extracorporeal membrane oxygenation (VA ECMO), with additional studies showing an altered cerebrovascular response to NG-nitro-L-arginine methyl ester in lamb cerebral vessels in this same model. OBJECTIVE: To further study the mechanisms involved in altered cerebrovascular responses in vessels exposed to VA ECMO. DESIGN: Prospective study. SETTING: Research Animal Facility at Children's National Medical Center, Washington, DC. SUBJECT: Newborn lambs, 1-7 days of age, 4.76 +/- 0.8 kg (n = 10). METHODS: Animals randomly assigned two groups, control and VA ECMO, were anesthetized, ventilated, heparinized, and kept in a normal physiologic condition. Control animals were continued on ventilatory support, whereas animals in the VA ECMO groups were placed on VA ECMO, with bypass flows maintained between 120 and 200 mL x kg x min(-1) for 2.5 hrs. Isolated third-order branches of the middle cerebral arteries were studied for myotonic reactivity to increasing intraluminal pressure changes, response to acetylcholine, an endothelium-dependent vasodilator, 3-morpholinyl-sydnoneimine chloride, an endothelium-independent vasodilator, and serotonin, a direct vascular vasoconstrictor. Arterial caliber was monitored using video microscopy. RESULTS: Myogenic constriction response was significantly decreased in the VA ECMO group compared with the control group (p = .03). Intraluminal acetylcholine caused concentration-dependent arterial dilation in the control group, whereas it resulted in vasoconstriction in the VA ECMO group (p = .008). There were no significant differences in dilation responses to 3-morpholinyl-sydnoneimine chloride and contractile responses to serotonin among the groups. CONCLUSION: Cerebral arteries exposed to VA ECMO had impaired myogenic responses combined with altered endothelial function. The endothelial alteration seems to be mediated through the nitric oxide pathway, with recovery noted after addition of a nitric oxide donor. It can be postulated that these changes may reflect the mechanisms for the impairment of cerebral autoregulation previously reported in this lamb model.

Validation of the CAS neonatal NIRS system by monitoring vv-ECMO patients: preliminary results.

The CAS neonatal NIRS system determines absolute regional brain tissue oxygen saturation (SnO2) and brain true venous oxygen saturation (SnvO2) non-invasively. Since NIRS-interrogated tissue contains both arterial and venous blood from arterioles, venules, and capillaries, SnO2 is a mixed oxygen saturation parameter, having values between arterial oxygen saturation (SaO2) and cerebral venous oxygen saturation (SvO2). To determine a reference for SnO2, the relative contribution of SvO2 to SaO2 drawn from a brain venous site vs. systemic SaO2 is approximately 70:30 (SvO2:SaO2). If the relationship of the relative average contribution of SvO2 and SaO2 is known and does not change to a large degree, then NIRS true venous oxygen saturation, SnvO2, can be determined non-invasively using SnO2 along with SaO2 from a pulse oximeter.

Follow-up study of adolescents exposed to di(2-ethylhexyl) phthalate (DEHP) as neonates on extracorporeal membrane oxygenation (ECMO) support.

Di(2-ethylhexyl) phthalate (DEHP) is used to make polyvinyl chloride (PVC) plastic tubing soft and flexible. Animal data show that adverse effects of DEHP exposure may include reduced fertility, reduced sperm production in males, and ovarian dysfunction in females. Known treatments that involve high DEHP exposures are blood exchange transfusions, extracorporeal membrane oxygenation (ECMO), and cardiovascular surgery. Although potential exposure to DEHP in ECMO patients is significant, the exposure has not been associated with short-term toxicity. To evaluate long-term toxicity, we undertook a study of neonatal ECMO survivors to assess their onset of puberty and sexual maturity. We evaluated 13 male and 6 female subjects at 14-16 years of age who had undergone ECMO as neonates. All subjects had a complete physical examination including measurements for height, weight, head circumference, and pubertal assessment by Tanner staging. The testicular volume and the phallic length were measured in male participants. Laboratory tests included thyroid, liver, and renal function as well as measurements of luteinizing hormone, follicle-stimulating hormone, testosterone for males, and estradiol for females. Except for one patient with Marfan syndrome, the rest had normal growth percentile for age and sex. All had normal values for thyroid, liver, and renal functions. Sexual hormones were appropriate for the stage of pubertal maturity. Our results indicate that adolescents exposed to significant quantities of DEHP as neonates showed no significant adverse effects on their physical growth and pubertal maturity. Thyroid, liver, renal, and male and female gonadal functions tested were within normal range for age and sex distribution. Key Words: DEHP, ECMO, toxicity.

The use of intratracheal pulmonary ventilation and partial liquid ventilation in newborn piglets with meconium aspiration syndrome.

OBJECTIVE: To determine whether intratracheal pulmonary ventilation (ITPV) combined with partial liquid ventilation (PLV) improves oxygenation and ventilation at lower mean airway and peak inspiratory pressures when compared with conventional mechanical ventilation in a piglet model of meconium aspiration syndrome. DESIGN: Prospective, randomized, interventional study. SETTING: Animal Research Laboratory at the Children's National Medical Center, Washington, DC. SUBJECTS: Twenty newborn piglets, 1 to 2 wks of age, 1.8-2.8 kg in weight. INTERVENTION: The animals were anesthetized, paralyzed, and intubated with a 4.0 mm (internal diameter) endotracheal tube via a tracheostomy and were ventilated. Catheters were placed in the femoral artery and vein. Seven milliliters per kilogram of 20% human meconium was insufflated into the lungs over 30 mins. Dynamic pulmonary compliance was measured before and after instillation of meconium. Animals were ventilated to maintain arterial blood gases in a normal range, that is, pH = 7.35-7.45, Paco(2) = 40-45 torr (5.3-6.0 kPa), and Pao(2) = 70-90 torr (9.3-12.0 kPa). Ventilator settings were increased as needed to a maximum setting of Fio(2) = 1.0, peak inspiratory pressure (PIP) = 40 cm H(2)O, positive end-expiratory pressure = 5 cm H(2)O, and intermittent mandatory ventilation = 60 bpm. After a period of stabilization, 30 mL/kg of perflubron (Liquivent; Alliance Pharmaceutical Corp., San Diego, CA) was given intratracheally over 30 mins and the animals were randomized to either ITPV or control group. Measurements and RESULTS: Arterial blood gases were taken every 30 mins, and ventilatory settings were adjusted to achieve the targeted blood gas parameters. The animals' temperature, arterial blood pressure, heart rate, and oxygen saturation were monitored continuously. There was a significant decrease in the dynamic pulmonary compliance measurements in both groups immediately after meconium instillation. Compliance measurements after meconium instillation were similar in both groups (0.67 +/- 0.23 mL/cm H(2)O/kg ITPV; 0.88 +/- 0.46 mL/cm H(2)O/kg conventional, p =.17), indicating a similar degree of injury before the administration of perflubron. PIP and mean airway pressures were not significantly different at baseline; however, there was significant difference in PIP at 0, 2, and 4 hrs after administration of perflubron (p <.05). The maximum PIP and mean airway pressure were seen in both groups after meconium instillation before perflubron administration, with a mean PIP of 29.0 +/- 4.6 cm H(2)O in ITPV and 28.8 +/- 2.1 cm H(2)O in control. Mean airway pressure was significantly different between the two groups at 0, 1, 2, 3, and 4 hrs after perflubron administration. Lung pathology showed a uniform distribution of meconium in animals of both groups. The alveolar spaces were relatively clear of meconium and appeared to be well preserved. CONCLUSION: The results of this study indicate that ITPV combined with PLV allows for effective ventilation and oxygenation in piglets with meconium aspiration syndrome at lower mean airway pressure and PIP compared with conventional ventilation combined with PLV.

Continuous blood gas monitoring using an in-dwelling optode method: clinical evaluation of the Neotrend sensor using a luer stub adaptor to access the umbilical artery catheter.

INTRODUCTION: Arterial blood gases are essential in the management of critically ill neonates. A new technology using the Neotrend system (Diametrics Medical) allows for continuous measurement of pH, PaCO(2), and PaO(2), and calculates oxygen saturation, bicarbonate, and base excess. OBJECTIVE: To evaluate and compare the results of continuous blood gas measurement using the Neotrend system with a standard system of blood gas analysis in our intensive care unit. DESIGN: Prospective, controlled, interventional study. SETTING: The neonatal intensive care unit of a tertiary referral center. PATIENTS: Neonates with respiratory distress who required respiratory support and frequent arterial blood gas sampling and had a UAC. RESEARCH DESIGN AND METHOD: To enable Neotrend sensor access to an existing Argyle umbilical artery catheter (UAC) the catheter was cut at the 25-cm mark and connected to an 18-gauge blunt needle luer stub adaptor (Vygon 95440). The study began with the insertion of the Neotrend sensor. Subjects remained on the study until the UAC was discontinued and/or frequent blood gases were no longer needed. The blood gas results from the Neotrend system were not used in clinical management of the patient. BLOOD GAS MEASUREMENT: During the study period, with each blood sample drawn for laboratory analysis, a printout from the Neotrend monitor was recorded for comparison. RESULTS: A total of 217 pairs of blood gas samples were collected from seven neonates. The mean bias/precision for pH was 0.01/0.04; for PaO(2) 0.72/18.5 mm Hg; and for PaCO(2) 3.96/2.63 mm Hg. The correlation (r value) between the sensor reading and the blood gases were 0.85 for pH, 0.96 for PaO(2), and 0.92 for PaCO(2). CONCLUSION: The blood gases compared in the two methods had a strong correlation for pH, PaCO(2), PaO(2), and oxygen saturation. Although the bicarbonate and base excess values showed suboptimal statistical correlation, the difference was not clinically relevant. Results of this study indicate that this technology provides an accurate means of monitoring continuous blood gas parameters in neonatal patients. It also allows reduced healthcare provider exposure to blood and decreased patient iatrogenic blood loss.

Continuous blood gas monitoring using an in-dwelling optode method: comparison to intermittent arterial blood gas sampling in ECMO patients.

INTRODUCTION: The ability to measure postmembrane arterial blood gases is essential in the management of critically ill neonates treated with extracorporeal membrane oxygenation (ECMO). A new technology using, the Paratrend 7 system (Diametrics Medical, High Wycombe,UK) allows for continuous measurement of pH, PCO(2) and PO(2), and calculates oxygen saturation, bicarbonate, and base excess. OBJECTIVE: To evaluate and compare the results of continuous blood gas measurement using the Paratrend 7 system with a standard system of blood gas analysis in our intensive care unit. DESIGN: Prospective, controlled, interventional study. SETTING: The neonatal intensive care unit of a tertiary referral center. PATIENTS: Neonates who required extracorporeal life support and were expected to have frequent postmembrane arterial blood sampling during the testing period. RESEARCH DESIGN AND METHOD: To enable Paratrend 7 sensor access to the ECMO circuit, the postmembrane access port extension set that is routinely used for blood drawn for blood gas analysis was used. The study began with the insertion of the Paratrend 7 sensor. Subjects remained on the study until the ECMO was discontinued and/or frequent blood gases were no longer needed. The blood gas results from the Paratrend 7 system were not used in clinical management of the patient. BLOOD GAS MEASUREMENT: During the study period, with each blood sample drawn for laboratory analysis, a printout from the Paratrend 7 monitor was recorded for comparison. RESULTS: A total of 242 pairs of blood gas samples were collected from 10 neonates. The mean bias/precision for pH was -0.02/0.04; for PO(2) 68.35/93.44 mm Hg; and for PCO(2) 1.75/4.23 mm Hg. The correlation (r value) between the sensor reading and the blood gases were 0.89 for pH, 0.96 for PO(2), and 0.73 for PCO(2) (Table 1). CONCLUSION: The blood gases compared in the two methods had a strong correlation for pH, PCO(2) and PO(2). Results of this study indicate that this technology provides an accurate means of monitoring continuous blood gas parameters in neonatal ECMO patients. Use of the Paratrend 7 should allow reduced health-care provider exposure to blood and decreased patient iatrogenic blood loss.

High surgical burden for infants with severe chronic lung disease (sCLD).

BACKGROUND/PURPOSE: Infants with severe chronic lung disease (sCLD) may require surgical procedures to manage their medical problems; however, the scope of these interventions is undefined. The purpose of this study was to characterize the frequency, type, and timing of operative interventions performed in hospitalized infants with sCLD. METHODS: The Children's Hospital Neonatal Database was used to identify infants with sCLD from 24 children's hospital's NICUs hospitalized over a recent 16-month period. RESULTS: 556 infants were diagnosed with sCLD; less than 3% of infants had operations prior to referral and 30% were referred for surgical evaluation. In contrast, 71% of all sCLD infants received ≥1 surgical procedure during the CHND NICU hospitalization, with a mean of 3 operations performed per infant. Gastrostomy insertion (24%), fundoplication (11%), herniorrhaphy (13%), and tracheostomy placement (12%) were the most commonly performed operations. The timing of gastrostomy (PMA 48±10 wk) and tracheostomy (PMA 47±7 wk) insertions varied, and for infants who received both devices, only 33% were inserted concurrently (13/40 infants). CONCLUSIONS: A striking majority of infants with sCLD received multiple surgical procedures during hospitalizations at participating NICUs. Further work regarding the timing, coordination, perioperative complications, and clinical outcomes for these infants is warranted.

Improving hand hygiene compliance in health care workers: Strategies and impact on patient outcomes.

BACKGROUND: We described a systematic process for improving hand hygiene (HH) compliance in health care providers and assessed the impact of HH on patient outcomes. METHODS: This retrospective cohort study was conducted between July 2008 and September 2011 in a children's hospital. We employed failure mode effectiveness analysis to identify barriers for complying with HH requirements and instituted improvement measures. We conducted a subanalysis using methicillin-resistant Staphylococcus aureus (MRSA) acquisition data and HH compliance data collected in the neonatal intensive care unit (NICU) to demonstrate the impact of HH on patient outcomes. RESULTS: The overall HH compliance rate increased from 50.3% preintervention (July 2008-September 2008) to 84.0% postintervention (January 2009-September 2011) (relative risk [RR], 1.7; 95% confidence interval [CI]: 1.6-1.9). Compliance among physicians and nurses increased from 48.6% to 87.0% (RR, 1.4; 95% CI: 1.3-1.6) and from 46.5% to 77.9% (RR, 1.3; 95% CI: 1.2-1.4), respectively. Sustaining HH at 80% or higher was associated with a 48% further reduction of MRSA acquisition (incident rate ratio, -0.52; 95% CI: -0.31 to -0.90) in a unit that had comprehensive MRSA prevention measures. This reduction represents the prevention of 1.3 MRSA acquisitions per month, resulting in a saving of 11.6 NICU-days and $66,397 hospital charges. CONCLUSION: This study demonstrated the utility of failure mode effectiveness analysis to improve staff HH and suggested HH as a potential cost-effective means for preventing MRSA in hospitals.

Clinical and economic impact of methicillin-resistant Staphylococcus aureus colonization or infection on neonates in intensive care units.

OBJECTIVE: The rising incidence and mortality of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection in children has become a great concern. This study aimed to determine the clinical and economic impact of MRSA colonization or infection on infants and to measure excess mortality, length of stay, and hospital charges attributable to MRSA. DESIGN: This is a retrospective cohort study. SETTING AND PATIENTS: The study included infants admitted to a level III-IV neonatal intensive care unit from September 1, 2004, through March 31, 2008. METHODS: A time-dependent proportional hazard model was used to analyze the association between MRSA colonization or infection and mortality. The relationships between MRSA colonization or infection and length of stay and between MRSA colonization or infection and hospital charges were assessed using a matched cohort study design. RESULTS: Of 2,280 infants, 191 (8.4%) had MRSA colonization or infection. Of 132 MRSA isolates with antibiotic susceptibility results, 106 were resistant to clindamycin and/or trimethoprim-sulfamethoxazole, thus representing a noncommunity phenotype. The mortality rate was 17.8% for patients with MRSA colonization or infection and 11.5% for control subjects. Neither MRSA colonization (hazard ratio [HR], 0.9 [95% confidence interval {CI}, 0.5-1.5]; P > .05 ) nor infection (HR, 1.2 [95% CI, 0.7-1.9]; P > .05 ) was associated with increased mortality risk. Infection caused by MRSA strains that were resistant to clindamycin and/or trimethoprim-sulfamethoxazole increased the mortality risk by 40% (HR, 1.4 [95% CI, 0.9-2.2]; P > .05 ), compared with the mortality risk of control subjects, but the increase was not statistically significant. MRSA infection independently increased length of stay by 40 days (95% CI, 34.2-45.6; P < .001) and was associated with an extra charge of $164,301 (95% CI, $158,712-$169,889; P < .001). CONCLUSIONS: MRSA colonization or infection in infants is associated with significant morbidity and financial burden but is not independently associated with increased mortality.

Clinical use of new-generation pulse oximeters in the neonatal intensive care unit.

Continuous monitoring by pulse oximetry is a common practice for preterm and critically ill newborns. A new generation of motion-tolerant pulse oximeters have been designed for improved clinical performance with a substantial reduction in alarm frequency. However, little is known about the differences among these new-generation pulse oximeters in the neonatal intensive care unit (NICU). The purpose of this study is to assess the clinical performance of two new-generation pulse oximeters in the NICU. Two new-generation pulse oximeters were used simultaneously to monitor 36 patients in the NICU. The two devices studied were the Philips FAST and the Masimo SET. Patients were randomly assigned for their digit selection and data were collected only when waveforms were of good quality and/or the pulse oximeter's pulse rate (PR) correlated with the electrocardiogram heart rate (HR). The data for oxygen saturation measurements, number of true and false alarms, and number of dropouts as well as the duration of dropouts for each pulse oximeter were recorded by the primary investigator at 5-minute intervals for a period of 2 hours on each patient. Dropouts are instances when the pulse oximeter alarm sounds due to its inability to identify the arterial pulse and provide an oxygen saturation reading. The mean gestational age for the study group was 32 weeks (rang, 24 to 42 weeks). Repeated-measures analysis of variance indicated no difference between the two devices across all time measurements (p=0.357). In addition, paired t-tests for true alarms and false alarms were not significant, with p-values of 0.151 and 0.869, respectively. There was a difference in the number of data dropouts (p<0.001): the Philips device had a nearly six-fold increase in the number of dropouts (Philips 247 versus Masimo 38). The duration of dropouts was also significant; the Philips device had three times longer duration of dropouts. Physiologic monitoring in the critical care setting requires accurate data measurements. The two new-generation pulse oximeters, the Philips FAST and Masimo SET, are equally sensitive in their ability to identify true and false alarms. Masimo pulse oximeter with its signal extraction technology, however, provides more consistent and accurate reporting of SpO2 values as demonstrated by its markedly decreased incidence of data dropouts. The Masimo unit appears to be more resistant to the effects of motion artifact.

Use of furosemide and hearing loss in neonatal intensive care survivors.

Hearing loss is a significant morbidity in survivors of the neonatal intensive care unit (NICU). The overall prevalence of hearing loss in neonates is 0.93 per 1000 live births, whereas in neonates weighing less than 2000 g, it is as high as 15.5 per 1000 live births. The increased incidence of hearing loss in NICU graduates has been attributed to their underlying disease process as well as exposure to ototoxic drugs including furosemide. A retrospective chart review of all neonatal intensive care survivors was done to evaluate the potential effect of furosemide on hearing loss. From July 2000 to January 2002, there were 57 neonates who received and 207 neonates who did not receive furosemide. The incidence of abnormal hearing screen was 15.5% in the furosemide group and 15.9% in the nonfurosemide group ( p = 0.9). Although the incidence of hearing loss is significantly higher in NICU graduates in comparison with the general neonatal population, it does not seem to be directly related to the use of furosemide.

Comparison of the effect of venovenous versus venoarterial extracorporeal membrane oxygenation on renal blood flow in newborn lambs.

UNLABELLED: Venovenous extracorporeal membrane oxygenation (VV ECMO) using double lumen catheters is an alternative to venoarterial (VA) ECMO and allows for total blood flow using the patient's cardiac output in comparison to partial blood flow provided during VA ECMO. OBJECTIVE: To compare the effects of VV versus VA ECMO on renal blood flow. DESIGN: Prospective study. SETTING: Research laboratory in a hospital. SUBJECT: Newborn lambs 1-7 days of age (n = 15). INTERVENTIONS: In anesthetized, ventilated lambs, femoral artery and vein were cannulated for monitoring and renal venous blood sampling. An ultrasonic flow probe was placed on the left renal artery for continuous renal blood flow measurements. Animals were randomly assigned to control (non-ECMO), VV ECMO and VA ECMO groups. After systemic heparinization, the animals were cannulated and studied at bypass flows of 120 mL/kg/min (partial bypass) for two hours in both ECMO groups and 200 mL/kg/min (full bypass) for an additional 30 min in the VA group. Changes in blood pressure and renal flow on ECMO and during ECMO bridge unclamping were recorded continuously. Plasma renin activity (PRA) levels were sequentially sampled. RESULTS: Systemic blood pressure was not different in VV or VA ECMO at partial bypass flow. However, systemic blood pressure increased significantly at maximal bypass flow in the VA ECMO group. There was no change in renal flow in either VV or VA ECMO groups. PRA levels did not correlate with bypass flow change. During unclamping of the ECMO bridge, blood pressure and renal flow drop significantly in the VA group, but not in the VV group. CONCLUSION: VV and VA ECMO at partial bypass flows had comparable effect on blood pressure, renal blood flow and PRA level in this short-term study. However, unclamping of the ECMO bridges did differentially affect blood pressure and renal blood flow between VV and VA groups. We speculate that this repeated acute change in long-run VA ECMO support may play a role in the persistent hypertension seen in some patients.

Improved oxygenation with reduced recirculation during venovenous ECMO: comparison of two catheters.

OBJECTIVES: To determine whether the new double-lumen catheter made by OriGen Biomedical (Austin, TX) for venovenous (VV) extracorporeal membrane oxygenation (ECMO) would reduce recirculation and improve oxygenation during VV ECMO when compared with the Kendall double-lumen catheter (Kendall Healthcare Products, Mansfield, MA). DESIGN: Prospective intervention study. SETTING: The animal research laboratory at Children's National Medical Center, Washington, DC. SUBJECTS: Nine newborn lambs one to seven days old and weighing 4.4 +/- 0.8 kg. INTERVENTION: Animals were anesthetized, intubated, and ventilated. The ductus arteriosus was ligated. Femoral arterial and venous, cephalic jugular vein, and pulmonary artery catheters were placed. After systemic heparinization, the catheter to be tested, an OriGen catheter, was placed in the right internal jugular vein and advanced into the right atrium. The animal was placed on ECMO and stabilized, with the ventilator settings decreased to a peak inspiratory pressure of 15-20 cmH2O, peak end-expiratory pressure of 5 cmH2O, rate of 15-25 breaths/min, and a fractional inspired oxygen concentration of 0.21-0.30. ECMO flows were increased in 100-ml increments from 200 to 600 ml/min with measurements taken 15 min after each change. The OriGen catheter was removed, the Kendall catheter was placed, and the studies were repeated. MEASUREMENTS AND MAIN RESULTS: Heart rate, mean blood pressure, PaO2, jugular cerebral oxygen saturation, pulmonary artery oxygen saturation, pump venous oxygen saturation, and postmembrane circuit pressures were measured at each study period. The OriGen catheter improved oxygenation, with higher systemic PaO2, higher pulmonary artery and cerebral oxygen saturations, and lower pump venous oxygen saturations (indicating less recirculation). With the OriGen catheter, PaO2 levels ranged from 69 +/- 18 mmHg [9.2 +/- 2.4 kPa] to 114 +/- 45 mmHg [15.2 +/- 6.0 kPa], compared range from 61 +/- 15 mmHg [8.1 +/- 2.0 kPa] to 87 +/- 34 mmHg [11.5+/-4.5 kPa] for the Kendall catheter. These findings indicate that, at all flow rates studied, less recirculation occurred with the OriGen catheter than with the Kendall catheter. The postmembrane pressures were significantly lower for the OriGen catheter at any given flow (from 30 +/- 5 to 122 +/- 18 mmHg) when compared with the Kendall catheter (from 77+/- 16 to 330+/-78 mmHg). CONCLUSIONS: These findings indicate that the OriGen catheter resulted in a reduction of recirculation, thereby resulting in an improvement in oxygenation while on VV ECMO. The lower postmembrane pressure potentially could reduce the risk of ECMO circuit complications such as tubing rupture, bleeding complications, as well as hemolysis. This new catheter makes VV ECMO more effective and represents a design that could be used for neonatal and/or pediatric ECMO.