Effect of high altitude on neutrophil counts in newborn infants

Simple Hematological Markers in Predicting the Severity of Transient Tachypnea of Newborn: New Wine in Old Bottles

OBJECTIVES

To evaluate the validity of red cell distribution width (RDW), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and platelet mass index (PMI) of patients with transient tachypnea of the newborn (TTN), and to find out their roles in predicting severity of TTN.

PATIENTS AND METHODS

In this prospective study, hematological parameters (RDW, PMI) and ratios (NLR, PLR) of 147 patients with TTN and 147 full-term healthy controls were evaluated and compared at birth and at 72nd h of life.

PATIENT

s with TTN and 147 full-term healthy controls were evaluated and compared at birth and at 72nd hours of life.

RESULTS

RDW and NLR were not only significantly higher in patients with TTN at birth (p = 0.001) and at 72nd hours of life (p: 0.001), but also were correlated with days of nasal continuous positive airway pressure therapy, duration of O2 therapy, TTN clinical scores, hospitalization and TTN duration. At a cut-off value of 2.40, NLR had a sensitivity of 82.5% and specificity of 77.5% to predict TTN, the most striking parameter at 72nd hours of life. RDW of 17.75 was also determined as the predictive cutoff value of TTN (sensitivity 72.5%; specificity 67.5%; area under the receiver-operating characteristic curve 0.80; p = 0.001). Multivariate analysis model adjusted for delivery, gestational age, male gender revealed that RDW and NLR were significantly and independently associated with TTN.

CONCLUSION

RDW and NLR both at birth and at 72nd hours of life can be used as biomarkers to distinguish TTN patients from healthy newborns and to predict the severity of TTN.

Awan Z, Abouzaid AA, Elbahaie HM, Al Amoudi SM, Andarawi M, F Shehata S. The Prevalence of Isolated Neutropenia at High Altitude in Southern Saudi Arabia: Does Altitude Affect Leucocyte Count?

INTRODUCTION

Isolated neutropenia is a common problem in hematology practice. Benign ethnic neutropenia (BEN) is the common form of neutropenia worldwide and it affects mainly African and Middle Eastern ethnicities. Most cases of isolated mild and moderate neutropenia are benign and associated with no clinical significance. The aim of this study was to estimate the prevalence of isolated neutropenia at high-altitude southern Saudi Arabia.

METHODS

A large dataset of complete blood counts (CBCs) was analyzed for walk-in patients of both genders, of age ranges from 12 to 60 years doing blood tests at a commercial lab for high altitude - 2,270 meters above sea level - (HA) group, and from sea level SL group. Abnormal biochemical or CBC results were excluded before analysis.

RESULTS

For HA group, 3123 CBCs were analyzed and for SL group 18,427 CBCs were analyzed. The prevalence of mild neutropenia, defined as absolute neutrophil count (ANC) in the range of 1.0-.5× 109/L, was 12.4% (n=399) versus 5.6% (n=1025), while moderate neutropenia, defined as ANC of 0.5-1 × 109/L, was present 6% (n=191) versus 1.45% (n=269) in the high altitude and sea level groups, respectively. Severe neutropenia, defined as neutrophil count less than 0.5-1 × 109/L, was rare in both groups.

CONCLUSION

Isolated neutropenia is common in Saudis living at high altitude. While benign ethnic neutropenia (BEN) is thought to be the major contributing factor to this high prevalence, other factors including environmental factors and altitude are possible contributing factors along with underlying ethnic neutropenia.

Gestation-wise Reference Ranges of Neutrophil Counts in Indian Newborns

Objectives

Blood counts are commonly performed tests in neonatal intensive care units with the results having various clinical ramifications. Interpreting blood counts as normal or abnormal requires reference ranges as per gestation. Studies on reference ranges for neonatal neutrophil counts are already scarce, and data is lacking in the Asian context. We sought to formulate gestation-wise reference ranges of neutrophil counts in an Indian setting.

Methods

Healthy, newborn babies of either gender, aged between 30 to 41 weeks gestation were included in the study. Gestational age was corroborated through first trimester dating scan and postnatally by the New Ballard Score. Single venous blood samples were drawn on day three and day five for estimation of total leukocyte count, differential count (neutrophils, lymphocytes), and peripheral blood smear examination.

Results

We evaluated the data of 420 newborns. The normative values were compiled week-wise for gestational ages of 30 to 41 weeks at birth. We observed a clustering of neutrophil count values below 8000 cells/μL on day three and below 5000 cells/μL on day five. No gender-based differences in counts were observed. We were able to generate reference range curves for neutrophil counts as per gestational age.

Conclusions

The absolute neutrophil counts of term and preterm Indian newborns are higher than the values depicted in the standard reference chart used currently. This indicates that a different standard chart as per gestation should be used in Indo-Asian countries to differentiate ‘normal’ from ‘abnormal’.

Screening and Serial Neutrophil Counts Do Not Contribute to the Recognition or Diagnosis of Late-Onset Neonatal Sepsis

OBJECTIVE

To determine the validity of screening and serial neutrophil counts in predicting the absence/presence of late-onset sepsis (LOS) in infants with central venous catheters.

STUDY DESIGN

Retrospective study of infants admitted to the neonatal intensive care unit (2009-2013) at Parkland Hospital with a central venous catheter and ≥1 LOS evaluations. Infants were categorized as proven or suspect LOS or uninfected based on results of blood cultures, clinical illness, and duration of antibiotics. Receiver operating curves (ROCs) were constructed to predict the absence or presence of LOS using Manroe reference ranges for total and immature neutrophils and the immature to total neutrophil ratio at 0, 12, and 24 hours after blood culture and the neutrophil value score, which assesses serial values.

RESULTS

Of the 497 infants with a central venous catheter, 179 underwent ≥1 LOS evaluations, and 140 of 179 (78%) had ≥1 complete evaluations (2 blood cultures and neutrophil values at 0, 12, and 24 hours), resulting in 188 complete LOS evaluations. The gestational age was 28 ± 4 weeks and LOS evaluation occurred at 29 ± 34 days (SD; 4-197 days). Sixty-one (35%) infants had proven LOS, 48 (23%) were suspect, and 71 (38%) were noninfected. ROC comparing proven vs noninfected was ≤0.56 for total neutrophils, immature neutrophils, and immature to total neutrophil ratio at 0, 12, and 24 hours and similar for proven + suspect vs noninfected. ROC for neutrophil value scores and absence of LOS was 0.56.

CONCLUSIONS

Screening neutrophil values are poor predictors of LOS in neonates with a central venous catheter, as are serial neutrophils and the neutrophil value score. Alternative biomarkers are needed.

Evaluation of altitude-appropriate reference ranges for neutrophils in diagnosis of sepsis in very low birth weight infants: A multicenter retrospective study

Background

The circulating neutrophil count was commonly believed to be influenced by altitude. At present, neutrophil reference ranges (RRs) for very low birth weight (VLBW) neonates are only available from the sea level and from high altitude. This study aimed to construct RRs for neutrophils in VLBW infants in an intermediate-altitude area and assess its usefulness in evaluation for sepsis.

Methods

This was a multicenter retrospective study of 2173 VLBW infants admitted to 20 hospitals in Chongqing in southwest of China with altitude from 1000 to 2600 feet. The RRs for absolute total neutrophils (ATN), absolute total immature neutrophils (ATI), and immature: total neutrophil proportion were constructed based on “normal” neonates (unlikely infection). Values of neutrophil from septic and uninfected neonates were respectively assessed using the revised RRs and the previous Mouzinho’s and Schmutz’s RRs. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were compared using the McNemar’s test or χ² test.

Results

The upper limits for ATN and ATI using the revised RRs were much higher than those using Mouzinho’s RRs, but lower than those using Schmutz’s RRs. The revised RRs and Mouzinho’s RRs had higher sensitivities than Schmutz’s RRs at 73–672 h. The revised RRs had a higher specificity than Mouzinho’s RRs at both 0–72 h and 73–672 h. The NPV for any abnormality in neutrophil values was high at both 0–72 h and 73–672 h irrespective of the RRs used.

Conclusion

Altitude-appropriate RRs for neutrophils is more suitable to guide the diagnosis and management of neonatal sepsis in VLBW infants.

Neutropenia in the newborn

PURPOSE OF REVIEW

The aim is to review normal blood neutrophil concentrations and the clinical approach to neutropenia in the neonatal period. A literature search on neonatal neutropenia was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies.

RECENT FINDINGS

The review summarizes current knowledge on the causes of neutropenia in premature and critically ill neonates, focusing on common causes such as maternal hypertension, neonatal sepsis, twin-twin transfusion, alloimmunization, and hemolytic disease. The article provides a rational approach to diagnosis and treatment of neonatal neutropenia, including current evidence on the role of recombinant hematopoietic growth factors.

SUMMARY

Neutrophil counts should be carefully evaluated in premature and critically ill neonates. Although neutropenia is usually benign and runs a self-limited course in most neonates, it can be prolonged, and it constitutes a serious deficiency in antimicrobial defense in some infants.

Serial neutrophil values facilitate predicting the absence of neonatal early-onset sepsis

OBJECTIVE

To validate established neonatal neutrophil reference ranges (RRs) and determine the utility of serial measurements of neutrophil values in the first 24 hours to predict the absence of neonatal early-onset sepsis (EOS).

STUDY DESIGN

Retrospective study of 2073 admissions to the neonatal intensive care unit (2009-2011). Neonates were classified as blood culture-positive, proven EOS (n = 9), blood culture-negative but clinically suspect EOS (n = 292), and not infected (n = 1292). Neutrophil values from 745 not-infected neonates without perinatal complications were selected to validate RR distributions. Positive and negative predictive values were calculated; area under receiver operating characteristic curves (AUCs) were constructed to predict the presence or absence of EOS. Neutrophil value scores were established to determine whether serial neutrophil values predict the absence of EOS.

RESULTS

Seventy-seven percent of admissions to the neonatal intensive care unit were evaluated for EOS: 9 (0.56%) had proven EOS with positive blood culture ≤ 37 hours; 18% had clinically suspect EOS. Neutropenia occurred in preterm neonates, and nonspecific neutrophilia was common in uninfected neonates. The distribution of neutrophil values differed significantly between study groups. The specificity for absolute total immature neutrophils and immature to total neutrophil proportions was 91% and 94%, respectively, with negative predictive value of 99% for proven and 78% for proven plus suspect EOS. Absolute total immature neutrophils and immature to total neutrophil proportions had the best predictability for EOS >6 hours postnatal with an AUC ∼ 0.8. Neutrophil value scores predicted the absence of EOS with AUC of 0.9 and 0.81 for proven and proven plus suspect EOS, respectively.

CONCLUSION

Age-dependent neutrophil RRs remain valid. Serial neutrophil values at 0, 12, and 24 hours plus blood culture and clinical evaluation can be used to discontinue antimicrobial therapy at 36-48 hours.

Isolated elevated blood neutrophil concentration at altitude does not require NICU admission if appropriate reference ranges are used

OBJECTIVE

The Intermountain Healthcare hospitals use a clinical pathway algorithm for early-onset infection, which is based on the 2002 Centers for Disease Control and Prevention (CDC) guidelines for perinatal group B streptococcal disease. As part of this pathway, neonates in the well baby nursery, who seem to be well but have risk factors for infection, receive a 'limited laboratory evaluation including a CBC', and if the complete blood cell count (CBC) is abnormal, antibiotic treatment and neonatal intensive care unit (NICU) monitoring are initiated. We recently found that reference ranges for absolute neutrophil counts (ANCs) are much wider at our altitude (4800 to 5000 ft) than at sea level. On this basis, we speculated that some well babies with risk factors for infection are mistakenly judged as having an abnormal CBC, and are unnecessarily admitted to the NICU.

STUDY DESIGN

This was a retrospective observational cohort study of neonates of >37 weeks gestation admitted to either of two Intermountain Healthcare NICUs for intravenous antibiotic treatment during a recent 36-month period.

RESULTS

During the study period 3217 patients were admitted to the two NICUs, 1049 (32.6%) of which were born at>37 weeks gestation. Of these, 14 (1.3%) were found to have been admitted to the NICU on the basis of an abnormal CBC (elevated ANC), when in retrospect, using the appropriate ANC chart, their CBCs were completely normal. None of the 14 neonates had a leukocyte left shift (immature to total neutrophil ratio >0.3) or thrombocytopenia. None were treated with supplemental oxygen or mechanical ventilation in the NICU. All 14 had sterile blood cultures. All had antibiotics stopped in 48 to 72 h, and all were discharged home as well babies.

CONCLUSION

We identified 14 neonates who, while in the well baby nursery, were found to have risk factors for early-onset infection, but did not seem to be infected, and were subsequently admitted to a NICU for intravenous antibiotic treatment and monitoring under the mistaken impression that they had an abnormal CBC. We maintain that use of an appropriate neutrophil reference range chart can reduce NICU admissions and can limit unnecessary antibiotic exposure.

Expected ranges for blood neutrophil concentrations of neonates: the Manroe and Mouzinho charts revisited

BACKGROUND

Upper and lower reference limits for blood neutrophil concentrations of neonates were reported by Manroe, Rosenfeld and co-workers in 1979 and by Mouzinho, Rosenfeld and co-workers in 1994. Studies by Carballo and co-workers and Maynard and co-workers suggested that at high altitude a much higher upper limit of values occurs, and that neutrophilia is often diagnosed inappropriately, at high altitude, if the Manroe and Mouzinho charts are used.

STUDY DESIGN

We revisited the Manroe and Mouzinho charts using modern cell counting instrumentation and very large sample sizes. This was accomplished with data from an 18-hospital health-care system, at hospitals averaging 4,800 feet above sea level. Data were obtained from neonates in the first 10 days following birth, using tests performed on a single type of automated blood cell counter (Beckman Coulter LH 750, Fullerton, CA, USA). To obtain a description of 'expected values,' patients with the following diagnoses, known to have a high proportion of abnormal neutrophil counts, were excluded from the analysis; (1) maternal pregnancy-induced hypertension, (2) early-onset bacterial sepsis, (3) a discharge diagnosis of congenital neutropenia and (4) trisomy 21, 18 or 13.

RESULT

Blood neutrophil concentrations were tabulated from 30 354 tests performed on neonates of 23 to 42 weeks gestation, with dates of birth between 1 January 2004 and 31 May 2007. The reference range charts generated from these data have much higher upper value limits than do the Manroe and Mouzinho charts, and are similar to the high-altitude reports of Carballo and co-workers and Maynard and co-workers. Neonates whose mothers labored before delivery had significantly higher neutrophil counts (averaging 3,500 neutrophils per mul higher, P<0.0001; comparing cesarean section deliveries with vs without labor). Females had significantly higher counts (averaging 2,000 neutrophils per mul higher) than males (P<0.0001). Counts did not differ on the basis of racial/ethnic group.

CONCLUSION

The figures of this report describe the expected ranges for blood neutrophil concentrations over the first 10 days of life among neonates of 23 to 42 weeks gestation at high altitude.

Neonatal sepsis workups in infants >/=2000 grams at birth: A population-based study

BACKGROUND

Few data are available on the outcome of neonatal sepsis evaluations in an era when intrapartum antibiotic therapy is common.

METHODS

We identified all newborns weighing >/=2000 g at birth who were ever evaluated for suspected bacterial infection at 6 Kaiser Permanente hospitals between October 1995 and November 1996, reviewed their records and laboratory data, and tracked them to 1 week after discharge. We analyzed the relationship between key predictors and the presence of neonatal bacterial infection.

RESULTS

Among 18 299 newborns >/=2000 g without major congenital anomalies, 2785 (15.2%) were evaluated for sepsis with a complete blood count and/or blood culture. A total of 62 (2.2%) met criteria for proven, probable, or possible bacterial infection: 22 (.8%) had positive cultures and 40 (1.4%) had clinical evidence of bacterial infection. We tracked all but 10 infants (.4%) to 7 days postdischarge. There were 67 rehospitalizations (2.4%; 2 for group B streptococcus bacteremia). Among 1568 infants who did not receive intrapartum antibiotics, initial asymptomatic status was associated with decreased risk of infection (adjusted odds ratio [AOR]:.26; 95% confidence interval [CI]:.11-.63), while chorioamnionitis (AOR: 2. 40; 95% CI: 1.15-5.00), low absolute neutrophil count (AOR: 2.84; 95% CI: 1.50-5.38), and meconium-stained amniotic fluid (AOR: 2.23; 95% CI: 1.18-4.21) were associated with increased risk. Results were similar among 1217 infants who were treated, except that maternal chorioamnionitis was not significantly associated with neonatal infection.

CONCLUSIONS

The risk of bacterial infection in asymptomatic newborns is low. Evidence-based observation and treatment protocols could be defined based on a limited set of predictors: maternal fever, chorioamnionitis, initial neonatal examination, and absolute neutrophil count. Many missed opportunities for treating mothers and infants exist.