Partial pressure of carbon dioxide in extremely low birth weight infants supported by nasal prongs continuous positive airway pressure

Review of pediatric hypercarbia and intraoperative management

PURPOSE OF REVIEW

Hypercarbia in pediatric patients is an important component of intraoperative management. Despite marked advances in medicine and technology, it is uncertain what the physiological CO2 range in neonates, infants and small children. This data is extrapolated from the adult population. We are going to review advantages and disadvantages of CO2 measurement techniques, causes and systemic effects of hypercarbia. We are going to discuss how to approach management of intraoperative hypercarbia.

RECENT FINDINGS

Although physiological range in this patient population may not be fully understood, it is known that any rapid change from a child's baseline increases risks of complications. Any derangements in CO2 are further compromised by hypoxia, hypotension, hypothermia, anemia, all of which may occur in a dynamic operating room environment.

SUMMARY

Pediatric anesthesiologists and their teams must remain vigilant and anticipate these developments. Care must be taken to avoid any rapid changes in these vulnerable patients to minimize risks of adverse outcomes.

Performance of the Silverman Andersen Respiratory Severity Score in predicting PCO2 and respiratory support in newborns: a prospective cohort study

OBJECTIVE

To determine if the Silverman Andersen respiratory severity score, which is assessed by physical exam, within 1 h of birth is associated with elevated carbon dioxide level and/or the need for increased respiratory support.

STUDY DESIGN

Prospective cohort study including 140 neonates scored within 1 h of birth. We report respiratory scores and their association with carbon dioxide and respiratory support within 24 h.

RESULTS

Carbon dioxide level correlated with respiratory score (n = 33, r = 0.35, p = 0.045). However, mean carbon dioxide for patients with score <5 vs. ≥5 did not differ significantly (56 vs. 67, p = 0.095). Patients with respiratory scores ≥5 had respiratory support increased within 24 h more often than those with scores <5 (79% vs. 28%, p < 0.001).

CONCLUSION

The Silverman Andersen respiratory severity score may be valuable for predicting need for escalation of respiratory support and facilitate decision making for transfer in low-resource settings.

Nursing Care Guidelines for prevention of nasal breakdown in neonates receiving nasal CPAP

Use of nasal continuous positive airway pressure (CPAP) is increasing as a means of respiratory support for respiratory distress syndrome in many premature neonates across the United States. Nasal CPAP is less invasive and may be as effective as mechanical ventilation in premature infants, and has been shown to cause less lung damage in premature neonates. Because of the increased use of nasal CPAP in neonates, especially younger and more fragile neonates, the presence of nare and nasal septum breakdown may be seen as a complication. Currently, all nasal CPAP systems use a hat and prong or mask type of delivery system. This appears to be effective for many neonates, but for some, it is difficult to appropriately fit the hat and prongs. The result of an inappropriately fitted device can be mild to severe nare and nasal septum damage. This article will discuss the need for nasal CPAP and the mechanics of nasal CPAP, but more importantly, serve to guide caregivers in the appropriate physical assessment and care of a neonate on nasal CPAP with the goal of preventing skin breakdown and nasal damage.

Oxygenation and ventilation in spontaneously breathing very preterm infants with nasopharyngeal CPAP in the delivery room

AIM

To provide data on ventilation, oxygenation and acid-base state from birth to 48 h in very preterm infants treated with lung recruitment manoeuvre and nasopharyngeal continuous positive airway pressure in the delivery room.

METHODS

Subjects of this prospective observational cohort study were 48 of 61 infants enrolled in a randomised controlled trial to test two lung recruitment manoeuvres after birth. The infants had received an arterial line in the delivery room. The outcome measures were data on oxygenation, ventilation and acid-base state during spontaneous breathing.

RESULTS

Data are presented as (n [%]; median [minimum-maximum]). 22 of 48 (46%) infants (gestational age, 26.4 [25.0-28.9] weeks; birth weight 870 [540-1310] g) were never intubated during the study. The FiO(2) of these infants was low (0.4 [0.21-0.45] at 45 min and 0.21 [0.21-0.5] at 48 h). PCO(2) reached its maximum at 24 (11-44) min (8 [6.4-10.8] kPa) and decreased below 6.7 kPa (median) within 3 h. The incidence of intracranial haemorrhage/periventricular leukomalacia did not increase with hypercapnia (pCO(2) > 8 kPa).

CONCLUSION

A transient period of hypercapnia after birth may occur in spontaneously breathing very preterm infants supported with nasopharyngeal continuous positive airway pressure in the delivery room. The incidence of cerebral damage was not increased in infants with hypercapnia.

Can delivery room management impact the length of hospital stay in premature infants?

OBJECTIVES

To evaluate the impact of initiating early nasal continuous positive airway pressure (ENCPAP) on the length of hospital stay (LOS) for the very low birth weight (VLBW) infants.

STUDY DESIGN

LOS at the George Washington University Hospital (GW) after the institution of ENCPAP policy was compared to benchmark values using two-tail t-tests. The incidence of neonatal morbidity was calculated using Bonferroni corrected 95% confidence interval as compared to benchmark rates (alpha=0.001). Comparisons were repeated after stratification of the population into four birth weight subcategories: group A (GrpA) (501 to 750 g), GrpB (751 to 1000 g), GrpC (1001 to 1250 g) and GrpD (1251 to 1500 g).

RESULTS

We studied 228 consecutive VLBW infants (birth weight: 995+/-294 g and gestational age: 27.7+/-2.7 weeks). Compared to benchmark values, the GW experience was associated with a significant reduction of 5.1 days in LOS (55.9+/-25.2 vs 61+/-32 days; P=0.04). The decrease in LOS was consistent in all subgroups, but was most noticeable in infants of the smallest weight subcategory (LOS in GrpA=86+/-21 vs 104+/-32, P=0.004; in GrpB=69.9+/-16.7 vs 79+/-27, P=0.018; in GrpC=48.2+/-13 vs 56+/-22, P<0.001 and in GrpD=31.7+/-12.5 vs 40+/-19, P=0.003). In the overall population, a lower incidence of chronic lung disease (CLD) (17.8 vs 29%, P<0.001) was also noted. There were no differences in mortality rates (9 vs 14%), or the incidence of necrotizing enterocolitis (NEC) (8 vs 6%) or intraventricular hemorrhage (6.2 vs 9%) between GW and the established benchmark rates.

CONCLUSION

ENCPAP may reduce LOS in VLBW infants in our study population. This relatively shorter LOS was associated with a lower incidence of CLD, which may be a contributing factor.

Is it safer to intubate premature infants in the delivery room?

OBJECTIVES

Early nasal continuous positive airway pressure (ENCPAP) has recently emerged in neonatal units as an acceptable alternative to routine intubation and mandatory ventilation. The risks and benefits of ENCPAP have yet to be established. In this study, we aimed to examine variables that influenced the decision to initiate ENCPAP in the delivery room (DR). We also explored potential harmful effects of early intubation and examined whether unsuccessful ENCPAP attempts might subject infants to any unforeseen morbidity.

METHODS

All inborn very low birth weight (VLBW) infants admitted to the NICU since the implementation of the ENCPAP policy were included in this retrospective study. Infants were stratified initially into 2 cohorts according to whether they were intubated in the DR or began ENCPAP. Infants were then stratified into 4 groups according to the respiratory management during their first week of life. Infants in group 1 were supported with ENCPAP in the DR and continued to receive continuous positive airway pressure (CPAP) at least for the entire first week. Infants in group 2 began ENCPAP treatment in the DR but required intubation during the first week of life. Infants in group 3 were intubated in the DR but transitioned successfully to CPAP within the first 48 hours and were treated with CPAP for the first week of life or longer. Infants in group 4 were intubated in the DR and treated with intermittent mandatory ventilation for >48 hours. Univariate analyses compared different groups with the Wilcoxon nonparametric test, Kruskal-Wallis test, and analysis of variance. A multivariate regression model adjusted for differences in birth weights (BWs), gestational ages (GAs), race, and Apgar scores between the groups.

RESULTS

A total of 234 VLBW infants (weight of <1500 g) were admitted to the NICU during the period from August 1997 to December 2003. The mean BW was 977.1 +/- 305.8 g, and the mean GA was 27.7 +/- 2.7 weeks. The overall mortality rate was 11.1%, and the incidence of bronchopulmonary dysplasia among survivors was 17.4%. ENCPAP was implemented successfully in the DR for 151 (64.5%) infants, whereas 83 (35.5%) infants required intubation. Infants who required intubation had significantly lower GAs, BWs, and 1-minute Apgar scores. The use of ENCPAP in the DR increased significantly over time. The chance of successful maintenance with ENCPAP for >48 hours was not demonstrable at <24 weeks of gestation (10% success). Use of ENCPAP improved significantly by 25 weeks of gestation (45% success). Infants in group 1 required a shorter duration of oxygen use than did infants in group 3 (7.9 +/- 18.3 vs 39 +/- 32.7 days; regression coefficient [b] = 19 +/- 5.3). None of the infants in group 1 developed intraventricular hemorrhage of grade III or IV or retinopathy of prematurity of stage 3 or 4. Infants in group 3 did not show improved outcomes, compared with group 1. Compared with group 4, infants in group 2 had a higher incidence of necrotizing enterocolitis (15.6% vs 7.3%; b = 2.5 +/- 1.2).

CONCLUSIONS

The success of ENCPAP improved with increased GA and with staff experience over time. Infants treated successfully with ENCPAP were unlikely to develop intraventricular hemorrhage of grade III or IV. Infants who experienced ENCPAP failure were at increased risk for the development of necrotizing enterocolitis. Infants who were intubated briefly in the DR were at increased risk for prolonged oxygen requirement. An individualized approach should be considered for respiratory support of VLBW infants.