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ORIGINAL ARTICLE
Year : 2022  |  Volume : 11  |  Issue : 2  |  Page : 107-111

Hemodynamics of superior mesenteric artery by doppler flow velocimetry in enterally fed moderately asphyxiated newborns


1 Department of Pediatrics, Jawaharlal Nehru Medical College, A.M.U, Aligarh, Uttar Pradesh, India
2 Department of Radiodiagnosis, Jawaharlal Nehru Medical College, A.M.U, Aligarh, Uttar Pradesh, India

Date of Submission12-Aug-2020
Date of Decision16-Aug-2021
Date of Acceptance20-Aug-2021
Date of Web Publication20-Apr-2022

Correspondence Address:
Uzma Firdaus
Department of Pediatrics, Jawaharlal Nehru Medical College, A.M.U, Aligarh, Uttar Pradesh
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcn.jcn_131_20

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  Abstract 


Introduction: Asphyxia is an important cause of neonatal mortality and morbidity. The disturbed hemodynamics caused by asphyxia can damage a number of organ systems including gastrointestinal system. Enteral feedings can therefore be risky in the asphyxiated newborns with jeopardized blood supply. Objective: The objective of this study was to estimate the abnormal Doppler flow indices of splanchnic circulation in moderately asphyxiated term newborns on the 1st day of life. Design: This was a prospective case–control study. Study setting: This study was conducted in the Neonatology Division, Department of Pediatrics and Department of Radiodiagnosis, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh. Materials and Methods: This study included thirty hemodynamically stable asphyxiated babies as cases. The controls were gestation- as well as weight-matched normal newborns. Blood flow in the superior mesenteric artery (SMA) was estimated by Doppler ultrasonography within the first 24 h of birth of the baby. The peak systolic velocity, end-diastolic velocity, time-averaged mean velocity, and the resistive index were recorded. The measurement was done before and 1 h after giving feed to the baby. The pre- and postfeed Doppler indices of the SMA were measured and compared with the controls. The tolerance of oral feeds by the babies was regularly monitored. Results: The baseline velocity in the study group prior to feeding was comparable to the control group. None of the cases developed feed intolerance and showed a similar postfeed hemodynamic response in the SMA as that of controls. Conclusion: Enteral feeds could be safely started and continued in all the moderately asphyxiated term neonates within the 1st day of life after demonstrating establishment of splanchnic flow in the Doppler study.

Keywords: Doppler velocimetry, moderately asphyxiated newborns, splanchnic flow


How to cite this article:
Ashraf A, Firdaus U, Ali SM, Wahab S. Hemodynamics of superior mesenteric artery by doppler flow velocimetry in enterally fed moderately asphyxiated newborns. J Clin Neonatol 2022;11:107-11

How to cite this URL:
Ashraf A, Firdaus U, Ali SM, Wahab S. Hemodynamics of superior mesenteric artery by doppler flow velocimetry in enterally fed moderately asphyxiated newborns. J Clin Neonatol [serial online] 2022 [cited 2022 May 18];11:107-11. Available from: https://www.jcnonweb.com/text.asp?2022/11/2/107/343418




  Introduction Top


Asphyxia remains a significant cause of neonatal mortality and morbidity, despite the important advances in perinatal care.[1] Fetal hypoxia can cause redistribution of blood flow favoring cerebral circulation at the cost of other organ systems. Despite this, the central nervous system gets disturbed to varying degrees in 70% of neonates. In addition, the disturbed hemodynamics can cause damage to the renal, pulmonary, cardiac, and gastrointestinal systems.[2],[3] The gut typically undergoes intense metabolic activity after birth demanding an increase in the oxygen requirement as well as rate of gut blood flow. Inadequate blood supply and hypoxia to the digestive tract can adversely affect its normal functions.[4],[5] Various studies have shown that improved flow in superior mesenteric artery (SMA) following birth results in better tolerance of oral feeds and less chances of gastrointestinal complications.[6],[7] In contrast, hypoxia can potentially cause splanchnic vasoconstriction and decreased blood flow in the gut. This further potentiates bowel mucosal hypoxia and may result in mucosal injury resulting in feed intolerance.[4]

There are standard recommendations for management of severely asphyxiated newborns. However, the postresuscitation care of moderately asphyxiated newborns is not so clearly defined. Although the complications are less likely to occur in the latter, watchful expectancy and timely intervention is of paramount importance for improving the outcome. In the absence of standard guidelines, the medical personnel have to choose between oral feed and intravenous fluid shortly after birth for maintaining the glucose homeostasis. Early feeding with breast milk always appears to be a better option considering it is physiological and free of catheter-related complications. However, overzealous feeding may result in feed intolerance or in extreme cases, necrotizing enterocolitis (NEC). Studies addressing the basic feeding issues of stable moderately asphyxiated term newborns are largely unavailable. Therefore, the present study was designed to answer the following research question:

What is Doppler flow velocimetry of SMA on the 1st day of life in enterally fed moderately asphyxiated term newborns and its role in prediction of feed intolerance?

Objective of the study

The objective of this study was to estimate the Doppler flow indices of splanchnic circulation in moderately asphyxiated term newborns on the 1st day of life.


  Materials and Methods Top


This hospital-based prospective case–control study was conducted in the Neonatal Division, Department of Pediatrics in collaboration with Department of Radiodiagnosis, JNMCH, AMU, Aligarh, from November 2016 to October 2018. Stable term moderately asphyxiated neonates without any signs and symptoms of significant encephalopathy within the first 24 h of life were assessed for eligibility. The National Neonatal Perinatal Database 2000 defines moderate birth asphyxia as slow gasping breathing or an Apgar score of 4–6 at 1 min of age.[8] Thirty babies who were found eligible were taken as cases. The controls included stable nonasphyxiated gestation- and weight-matched babies. Babies with major congenital anomalies, with hospital stay of <48 h as well as babies with umbilical catheterization were excluded from the study. Ethical clearance was obtained from the Institutional Ethics Committee. After taking written informed consent from the parents of the eligible subjects, a detailed history and physical examination was done and recorded on a predesigned pro forma. The babies were regularly examined for cardiorespiratory stability as well as any evidence of encephalopathy based on Sarnat and Sarnat staging. The hemodynamically stable babies with moderate birth asphyxia were started on feeds (10 ml of expressed mother's breast milk) within 24 h following birth. Baseline (prefeed) abdominal girth was recorded on the pro forma. The tolerance to oral feeds was checked by repeated measurements of abdominal girth and feeds were continued if the child did not show any feature of feed intolerance. An increase of girth of >2 cm from the baseline and persistence of 50% or more of residual feeds after 2 h of feed was considered as feed intolerance. In addition, the babies were also monitored for any variation in general activity, cardiovascular, and respiratory functions following feed ingestion. Blood flow in the SMA was evaluated by pulsed Doppler ultrasonography using a high-frequency (7–12 MHZ) transducer (Toshiba Aplio XG machine) within the first 24 h. For Doppler study, the neonate was kept in a supine position and the probe was placed on the mid-abdomen above the umbilicus in the sagittal plane. After identifying the aorta, the celiac trunk and the SMA were traced a few millimeters after their emergence from the aorta in the sagittal plane. A clear image in real-time ultrasonography of the artery was obtained and correction was made for the angle of insonation. The color flow imaging was used to clearly identify the arteries. In transverse planes, the artery was displayed between the splenic vein anteriorly and the aorta posteriorly. The artery was displayed red as the flow was directed toward the transducer. When stable waveforms measurements were obtained, the curves were traced and the blood flow variables in each artery were calculated from at least three consecutive cardiac cycles of optimal quality. The final measurements were the mean of these three readings. The recorded blood flow variables were the peak systolic velocity (PSV), end-diastolic velocity (EDV), time-averaged mean velocity (TAMV), and the resistance index (RI): (PSV-EDV)/PSV. These measurements were done prefeed as well as 1 h postfeed. All the measurements were done by a single experienced investigator to avoid interobserver variability. The recorded Doppler indices were compared with the gestation- and weight-matched controls.

Sample size

A sample size of convenience was used. Thirty hemodynamically stable babies with moderate birth asphyxia were included as cases. The controls were weight- and gestation-matched normal newborns.

Statistical analysis

Data were described in terms of mean ± standard deviation (±SD) and percentages when appropriate. The comparison of numerical variables between the study groups was done using Student's t-test. P values lower than 0.05 were considered statistically significant. All statistical calculations were carried out using SPSS 20 (Statistical Package for the Social Science; SPSS Inc., Chicago, IL, USA) for Microsoft Windows.


  Results Top


The study included thirty moderately asphyxiated term newborns as cases (N) and thirty weight- and gestation-matched newborns as controls (n). [Table 1] shows the baseline characteristics of the cases and controls. The mean birth weight was 2.9 kg (SD = 0.31), and the majority were term babies; only four babies were postterm. [Table 2] shows the clinical and laboratory data of the cases. As is evident from the table, most of the babies required resuscitation in the form of bag and mask ventilation for <1 min. None of the included babies required the use of chest compression or medications. During hospital stay, a large proportion of babies exhibited features of neural hyperexcitability as per Sarnat and Sarnat staging, but none of the babies developed frank seizures. [Table 3] demonstrates the maternal characteristics of the study population.
Table 1: Baseline characteristics of the case and control groups

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Table 2: Laboratory and clinical data of the cases

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Table 3: Maternal characteristics of cases and controls

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The mean age (SD) of the baby at the time of Doppler study was 13.6 h (SD = 5.9) and 17.2 h (SD = 5.1) among cases and controls, respectively. The results of blood flow velocity in SMA are given in [Table 4] and [Figure 1]. The baseline values of Doppler velocities (PSV) were found to be almost comparable in both the groups. In both the groups, the PSV, EDV, and TAMV increased in response to feeding. The postfeed values of Doppler velocities (EDV, mean velocity [MV], and RI) were comparable in the two study groups. It is interesting to note that the difference in the Doppler indices pre- and postfeed (between cases and controls) was also not found to be statistically significant [Table 4]. None of the cases showed inability to accept oral feed or later intolerance to feeds in the form of change in abdominal girth, vomiting, increase prefeed residual volume, or abdominal wall tenderness.
Table 4: Feed-related changes in Doppler velocimetries among cases and controls

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Figure 1: Blood flow indices of cases and controls

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  Discussion Top


There is no clear-cut recommendation regarding early initiation of enteral feeds in moderately asphyxiated babies who are expected to have compromised splanchnic blood flow and increased risk of developing NEC. This study is probably the first Indian study to address the feeding issue of moderately asphyxiated term babies in an objective manner. The measurement of blood blow in the gut was assessed by performing the Doppler study of SMA in the cases and gestation- and weight-matched healthy babies who served as controls. The feed was started after documenting splanchnic flow indices and its tolerance was closely monitored by repeated clinical examinations. We found that the splanchnic blood flow velocity was comparable between the cases and controls. All the measured velocities (PSV, EDV, and TAMV) were shown to increase after giving feeds to the baby. Hemodynamic response to feeding within the first 24 h in moderately asphyxiated newborns did not differ significantly from normal healthy newborns.

For the reference values of normal blood flow velocities of SMA, we referred to the study by Leidig. The authors documented a significant change of the blood flow (PSV and MV) after feeds.[9] Similarly, we found a significant rise in PSV as well as MV postfeed in both the study groups. In an older work by Kempley and Gamsu, babies with clinical suspicion of NEC were subdivided into confirmed and unconfirmed NEC groups. The authors observed that mean SMA velocities were significantly different in the confirmed NEC group.[10] In our study, none of the babies developed NEC during the hospital stay and the mean SMA velocities were comparable in both controls and cases. Matasova et al. and Kočvarova et al. while studying term and preterm babies, respectively, found EDV to be negative in the initial 2 h of life which later became positive. We, however, observed EDV to be positive in all cases, though a postfeed rise in EDV was seen in our study.[11],[12]

Several study groups have found a significant correlation between feed tolerance and flow velocities on Doppler study in preterms.[7],[13] Bora et al. did a cohort study on small-for-gestational age (SGA) babies whose mother had reduced or absent end-diastolic flow (AEDF) in umbilical artery Doppler ultrasound, along with healthy SGA and AGA babies. The proportion of babies developing feed intolerance was significantly higher in babies with AEDF group than healthy SGA and AGA babies. The baseline TAMV was lower in the confirmed NEC group and decreased further after feeds in babies having feed intolerance.[14] In a recent work done by El Sayed et al., Doppler indices of SMA were compared among three groups of newborns: healthy preterm group, preterm with birth asphyxia, and healthy full-term babies. It was observed that early feed tolerance was significantly associated with rise of EDV and a fall in RI. Similarly, late feed tolerance group showed an adverse hemodynamic response in the form of fall in EDV and rise in RI.[15]

The major limitation of our study was its relatively small sample size. More such studies with a larger sample size are required to substantiate the observations found by us. Serial Doppler study till 72 h of age would also have been a better option. Another issue was regarding the timing of availability of Doppler machine. Doppler was available only during certain hours of the morning. Sicker babies with moderate asphyxia who showed earlier deterioration in clinical condition were not included in the study. Indian standard uses the Apgar score at 1 min as a marker for birth asphyxia which may be an oversimplification of the condition. In contrast, the AAP emphasizes upon the Apgar score at 5 min, multi-organ dysfunction, neurological involvement as well as the presence of acidosis.

Future studies with larger sample size are needed to corroborate the findings observed in this study. Similar findings as obtained by us may help in framing feeding protocols for such compromised babies. In addition to asphyxiated newborns, other high-risk cohorts of babies having high risk of feed intolerance and later NEC may be monitored by Doppler studies. Favorable Doppler studies may become an objective way for the prediction of feed tolerance and assimilation by such babies.


  Conclusion Top


Splanchnic flow as determined by the Doppler velocimetry was found to remain unaffected in all the moderately asphyxiated term newborns studied by us. Such babies showed a positive flow response to feed in the form of increase in flow velocity in SMA. Enteral feeds were safely started and continued in all the cases within the 1st day of life after demonstrating establishment of splanchnic flow. Future studies with larger sample size are needed to corroborate the findings observed in this study. This may help in framing recommendation regarding early feeding of stable moderately asphyxiated babies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Golubnitschaja O, Yeghiazaryan K, Cebioglu M, Morelli M, Herrera-Marschitz M. Birth asphyxia as the major complication in newborns: Moving towards improved individual outcomes by prediction, targeted prevention and tailored medical care. EPMA J 2011;2:197-210.  Back to cited text no. 1
    
2.
Antonucci R, Porcella A, Pilloni MD. Perinatal asphyxia in the term newborn. J Pediatr Neonat Individual Med 2014;3:e030269.  Back to cited text no. 2
    
3.
Martín-Ancel A, García-Alix A, Gayá F, Cabañas F, Burgueros M, Quero J. Multiple organ involvement in perinatal asphyxia. J Pediatr 1995;127:786-93.  Back to cited text no. 3
    
4.
Cloherty JP, Eichenwald EC, Hansen AR, Stark AR. Manual of Neonatal Care. 8th ed. Philadelphia: Lippincott Williams and Wilkins; 2012. p. 798.  Back to cited text no. 4
    
5.
Paulusova E, Matasova K, Zibolenova J, Lucanova L, Kocvarova L, Zibolen M. Very early postnatal changes in splanchnic circulation in term infants. Pediatr Radiol 2014;44:274-8.  Back to cited text no. 5
    
6.
Robel-Tillig E, Knüpfer M, Pulzer F, Vogtmann C. Blood flow parameters of the superior mesenteric artery as an early predictor of intestinal dysmotility in preterm infants. Pediatr Radiol 2004;34:958-62.  Back to cited text no. 6
    
7.
Fang S, Kempley ST, Gamsu HR. Prediction of early tolerance to enteral feeding in preterm infants by measurement of superior mesenteric artery blood flow velocity. Arch Dis Child Fetal Neonatal Ed 2001;85:F42-5.  Back to cited text no. 7
    
8.
National Neonatology Forum. Report of the National Neonatal Perinatal Database. AIIMS New Delhi; 2000. Available from: https://www.newbornwhocc.org/pdf/nnpd_report_2002-03.PDF. [Last accessed on 2019 Apr 30].  Back to cited text no. 8
    
9.
Leidig E. Pulsed Doppler ultrasound blood flow measurements in the superior mesenteric artery of the newborn. Pediatr Radiol 1989;19:169-72.  Back to cited text no. 9
    
10.
Kempley ST, Gamsu HR. Superior mesenteric artery blood flow velocity in necrotising enterocolitis. Arch Dis Child 1992;67:793-6.  Back to cited text no. 10
    
11.
Matasova K, Zibolen M, Kolarovszka H, Ciljak M, Baska T, Murgas D, et al. Early postnatal changes in superior mesenteric artery blood flow velocity in healthy term infants. Neuro Endocrinol Lett 2007;28:822-5.  Back to cited text no. 11
    
12.
Kočvarova L, Lucanova L, Zibolenova J, Paulusova E, Matasova K. Early postnatal changes in the superior mesenteric artery blood flow parameters in late preterm newborns – A pilot study. Acta Med Martiniana 2013;13:27-32.  Back to cited text no. 12
    
13.
Murdoch EM, Sinha AK, Shanmugalingam ST, Smith GC, Kempley ST. Doppler flow velocimetry in the superior mesenteric artery on the first day of life in preterm infants and the risk of neonatal necrotizing enterocolitis. Pediatrics 2006;118:1999-2003.  Back to cited text no. 13
    
14.
Bora R, Mukhopadhyay K, Saxena AK, Jain V, Narang A. Prediction of feed intolerance and necrotizing enterocolitis in neonates with absent end diastolic flow in umbilical artery and the correlation of feed intolerance with postnatal superior mesenteric artery flow. J Matern Fetal Neonatal Med 2009;22:1092-6.  Back to cited text no. 14
    
15.
El Sayed HL, Hamed MH, Hady DG. Splanchnic hemodynamics as a predictor of feeding tolerance in preterm neonates. J Clin Neonatol 2018;7:243-9.  Back to cited text no. 15
    


    Figures

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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