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N. B. Mathur, Sriram Krishnamurthy, T. K. Mishra, Evaluation of WHO Classification of Hypothermia in Sick Extramural Neonates as Predictor of Fatality, Journal of Tropical Pediatrics, Volume 51, Issue 6, December 2005, Pages 341–345, https://doi.org/10.1093/tropej/fmi049
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Abstract
The objective of this study is to correlate the severity of hypothermia in sick extramural neonates with fatality and physiological derangements. This is a prospective observational study carried out at the referral neonatal unit of a teaching hospital admitting extramural neonates. The subjects comprised of 100 extramural hypothermic neonates transported to the Referral neonatal unit. Neonates weighing more than 1000 g, with abdominal skin temperature less than 36.5°C at admission were included in the study. Hypothermia was classified as per WHO recommendations. Clinical features including age, weight, gestational age, clinical diagnosis, vitals, place of delivery, details of transportation and capillary filling time were recorded at the time of admission. Oxygen saturation was recorded by a pulse oximeter. Samples for sepsis screen, blood culture and blood glucose were taken at admission. During the study it was observed that fatality was 39.3% in mildly hypothermic babies, 51.6% in moderately hypothermic babies and 80% in severely hypothermic babies. However, the presence of associated illness (birth asphyxia, neonatal sepsis and respiratory distress), physiological derangements (hypoxia, hypoglycemia and shock) and weight less than 2000 g were associated with more than 50% fatality even in mildly hypothermic babies. When moderate hypothermia was associated with hypoxia or shock, the fatality was 83.3% and 90.9% respectively. Similarly, mild hypothermia with hypoglycemia was associated with 71.4% fatality. The conclusion drawn from this study is that the WHO classification of severity of hypothermia correlates with the risk of fatality. However, it considers only body temperature to classify severity of hypothermia. The presence of associated illness (birth asphyxia, neonatal sepsis and respiratory distress), physiological derangements (hypoxia, hypoglycemia and shock) and weight less than 2000 g should be considered adverse factors in hypothermic neonates. Their presence should classify hypothermia in the next higher category of severity in WHO classification.
Introduction
Hypothermia is an important cause of death in the newborn.1–6 Septicemia and hypoxemia in the neonatal period are likely to be complicated by hypothermia, hypoglycemia and hypoperfusion.7
Classification of severity of hypothermia has been lately defined by WHO. However, its utility and rationale has not been evaluated with reference to fatality and associated sickness. This prompted us to undertake the present study with the objective of correlating the severity of hypothermia (WHO classification) in sick extramural neonates with fatality.
Subjects and Methods
A total of 100 extramural hypothermic neonates transported to a referral neonatal unit of a teaching hospital were enrolled for the study. Neonates with abdominal skin temperature less than 36.5°C at admission were included in the study. Neonates weighing less than 1000 g were excluded.
Clinical features including age, weight, gestational age, clinical diagnosis, vitals and place of delivery were recorded at the time of admission. The diagnosis of associated morbidity was made as per the guidelines by National Neonatology Forum (NNF).8
Oxygen saturation was recorded with the help of a pulse oximeter. Perfusion was assessed by seeing the capillary filling time. Blood glucose levels were measured at the initiation of rewarming by using dextrostix. Simultaneously, the blood glucose estimation was done by using glucose oxidase method of Huggett and Nixon.9
The transportation vehicle and distance traversed were recorded at the time of admission on the basis of information provided by the relatives. The maximum and minimum city temperatures on that particular day were also recorded.
Sepsis screen10–12 was done routinely on every admitted baby and included peripheral smear for immature: total neutrophil count, total leukocyte count and micro ESR. The presence of two abnormal parameters was considered a positive sepsis screen.12 Samples for blood culture were also routinely taken.
The continuous variables were analyzed using Student's t-test and proportions by Chi-square test or Fischer test. Probability of 5% was considered significant.
Results
The mean abdominal skin temperature was 34.93 ± 1.397°C in the study subjects and 72% of the babies were moderately or severely hypothermic as per WHO classification. Fatality was 39.3%, 51.6% and 80% in mildly, moderately and severely hypothermic babies respectively.
In the present study, 36% of neonates were transported naked. Only 5% of the neonates had head covered by cap. None of the neonates were wearing gloves and stockings at admission. All the neonates were transported in open vehicles like cycle-rickshaw (14%), auto-rickshaw (50.9%), public bus (27%) and scooter (4%). Transportation distance was more than 5 km in 84% of the neonates.
Considering place of delivery, 52% of the total were home deliveries and 48% were hospital deliveries (Table 1). Difference in fatality between hypothermic babies weighing less than 2000 g and those weighing more than 2000 g was significant (p = 0.0276).
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . | ||||
---|---|---|---|---|---|---|---|---|
No. of subjects | 100 | 28 | 62 | 10 | ||||
Abdominal skin temp. (°C) Mean ± SD | 34.93 ± 1.397 | 36.136 ± 0.073 | 34.93 ± 0.746 | 31.5 ± 0.291 | ||||
Weight (g) Mean ± SD | 1969.5 ± 719.9 | 2049 ± 721 | 1936 ± 715.4 | 1954 ± 804 | ||||
Gestational age | ||||||||
Pre-term (<37 weeks) | 35 | 7 | 24 | 4 | ||||
Term (37–42 weeks) | 62 | 18 | 38 | 6 | ||||
Post-term (>42 weeks) | 3 | 3 | 0 | 0 | ||||
Age (hours) Mean ± SD | 56.45 ± 48.32 | 92.57 ± 86.11 | 41.85 ± 38.54 | 5.6 ± 3.12 | ||||
Gender of baby | ||||||||
Male | 52 | 18 | 26 | 8 | ||||
Female | 48 | 10 | 36 | 2 | ||||
Place of delivery | ||||||||
Home | 52 | 15 | 33 | 4 | ||||
Hospital | 48 | 13 | 29 | 6 | ||||
Intrauterine Growth | ||||||||
SGA | 37 | 11 | 24 | 2 | ||||
AGA | 63 | 17 | 38 | 8 | ||||
LGA | 0 | 0 | 0 | 0 |
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . | ||||
---|---|---|---|---|---|---|---|---|
No. of subjects | 100 | 28 | 62 | 10 | ||||
Abdominal skin temp. (°C) Mean ± SD | 34.93 ± 1.397 | 36.136 ± 0.073 | 34.93 ± 0.746 | 31.5 ± 0.291 | ||||
Weight (g) Mean ± SD | 1969.5 ± 719.9 | 2049 ± 721 | 1936 ± 715.4 | 1954 ± 804 | ||||
Gestational age | ||||||||
Pre-term (<37 weeks) | 35 | 7 | 24 | 4 | ||||
Term (37–42 weeks) | 62 | 18 | 38 | 6 | ||||
Post-term (>42 weeks) | 3 | 3 | 0 | 0 | ||||
Age (hours) Mean ± SD | 56.45 ± 48.32 | 92.57 ± 86.11 | 41.85 ± 38.54 | 5.6 ± 3.12 | ||||
Gender of baby | ||||||||
Male | 52 | 18 | 26 | 8 | ||||
Female | 48 | 10 | 36 | 2 | ||||
Place of delivery | ||||||||
Home | 52 | 15 | 33 | 4 | ||||
Hospital | 48 | 13 | 29 | 6 | ||||
Intrauterine Growth | ||||||||
SGA | 37 | 11 | 24 | 2 | ||||
AGA | 63 | 17 | 38 | 8 | ||||
LGA | 0 | 0 | 0 | 0 |
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . | ||||
---|---|---|---|---|---|---|---|---|
No. of subjects | 100 | 28 | 62 | 10 | ||||
Abdominal skin temp. (°C) Mean ± SD | 34.93 ± 1.397 | 36.136 ± 0.073 | 34.93 ± 0.746 | 31.5 ± 0.291 | ||||
Weight (g) Mean ± SD | 1969.5 ± 719.9 | 2049 ± 721 | 1936 ± 715.4 | 1954 ± 804 | ||||
Gestational age | ||||||||
Pre-term (<37 weeks) | 35 | 7 | 24 | 4 | ||||
Term (37–42 weeks) | 62 | 18 | 38 | 6 | ||||
Post-term (>42 weeks) | 3 | 3 | 0 | 0 | ||||
Age (hours) Mean ± SD | 56.45 ± 48.32 | 92.57 ± 86.11 | 41.85 ± 38.54 | 5.6 ± 3.12 | ||||
Gender of baby | ||||||||
Male | 52 | 18 | 26 | 8 | ||||
Female | 48 | 10 | 36 | 2 | ||||
Place of delivery | ||||||||
Home | 52 | 15 | 33 | 4 | ||||
Hospital | 48 | 13 | 29 | 6 | ||||
Intrauterine Growth | ||||||||
SGA | 37 | 11 | 24 | 2 | ||||
AGA | 63 | 17 | 38 | 8 | ||||
LGA | 0 | 0 | 0 | 0 |
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . | ||||
---|---|---|---|---|---|---|---|---|
No. of subjects | 100 | 28 | 62 | 10 | ||||
Abdominal skin temp. (°C) Mean ± SD | 34.93 ± 1.397 | 36.136 ± 0.073 | 34.93 ± 0.746 | 31.5 ± 0.291 | ||||
Weight (g) Mean ± SD | 1969.5 ± 719.9 | 2049 ± 721 | 1936 ± 715.4 | 1954 ± 804 | ||||
Gestational age | ||||||||
Pre-term (<37 weeks) | 35 | 7 | 24 | 4 | ||||
Term (37–42 weeks) | 62 | 18 | 38 | 6 | ||||
Post-term (>42 weeks) | 3 | 3 | 0 | 0 | ||||
Age (hours) Mean ± SD | 56.45 ± 48.32 | 92.57 ± 86.11 | 41.85 ± 38.54 | 5.6 ± 3.12 | ||||
Gender of baby | ||||||||
Male | 52 | 18 | 26 | 8 | ||||
Female | 48 | 10 | 36 | 2 | ||||
Place of delivery | ||||||||
Home | 52 | 15 | 33 | 4 | ||||
Hospital | 48 | 13 | 29 | 6 | ||||
Intrauterine Growth | ||||||||
SGA | 37 | 11 | 24 | 2 | ||||
AGA | 63 | 17 | 38 | 8 | ||||
LGA | 0 | 0 | 0 | 0 |
With regard to morbidity, 56% of babies were asphyxiated, 73% had sepsis, 19% had pneumonia, 42% had respiratory distress (meconium aspiration syndrome in 17%, hyaline membrane disease in 6% and pneumonia in 19%)(Table 2).
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Birth asphyxia | 50 (56) | 12 (50) | 30 (50) | 8 (87.5) |
Sepsis | 73 (63) | 20 (55) | 47 (63.8) | 6 (100) |
Respiratory distress | 42 (71.4) | 12 (41.6) | 14 (79.2) | 6 (100) |
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Birth asphyxia | 50 (56) | 12 (50) | 30 (50) | 8 (87.5) |
Sepsis | 73 (63) | 20 (55) | 47 (63.8) | 6 (100) |
Respiratory distress | 42 (71.4) | 12 (41.6) | 14 (79.2) | 6 (100) |
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Birth asphyxia | 50 (56) | 12 (50) | 30 (50) | 8 (87.5) |
Sepsis | 73 (63) | 20 (55) | 47 (63.8) | 6 (100) |
Respiratory distress | 42 (71.4) | 12 (41.6) | 14 (79.2) | 6 (100) |
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Birth asphyxia | 50 (56) | 12 (50) | 30 (50) | 8 (87.5) |
Sepsis | 73 (63) | 20 (55) | 47 (63.8) | 6 (100) |
Respiratory distress | 42 (71.4) | 12 (41.6) | 14 (79.2) | 6 (100) |
Sepsis screen was positive in 73% while blood culture was positive in 35% (Table 3). Isolates from neonates with culture positive sepsis included Klebsiella in 21, E.Coli in 8, Pseudomonas in 3 and Staphylococcus aureus in 3 babies.
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . |
---|---|---|---|---|
Culture positive | 35 | 9 | 24 | 2 |
Sepsis screen positive | 73 | 20 | 47 | 6 |
I: T ratio >0.2* | 67 | 19 | 43 | 5 |
TLC <5000** | 24 | 10 | 11 | 3 |
MicroESR >age in days +2 or >15 mm in 1st hour | 58 | 16 | 38 | 4 |
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . |
---|---|---|---|---|
Culture positive | 35 | 9 | 24 | 2 |
Sepsis screen positive | 73 | 20 | 47 | 6 |
I: T ratio >0.2* | 67 | 19 | 43 | 5 |
TLC <5000** | 24 | 10 | 11 | 3 |
MicroESR >age in days +2 or >15 mm in 1st hour | 58 | 16 | 38 | 4 |
*Immature: Total neutrophil count, **TLC = Total leukocyte count.
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . |
---|---|---|---|---|
Culture positive | 35 | 9 | 24 | 2 |
Sepsis screen positive | 73 | 20 | 47 | 6 |
I: T ratio >0.2* | 67 | 19 | 43 | 5 |
TLC <5000** | 24 | 10 | 11 | 3 |
MicroESR >age in days +2 or >15 mm in 1st hour | 58 | 16 | 38 | 4 |
. | All hypothermics . | Mild hypothermia . | Moderate hypothermia . | Severe hypothermia . |
---|---|---|---|---|
Culture positive | 35 | 9 | 24 | 2 |
Sepsis screen positive | 73 | 20 | 47 | 6 |
I: T ratio >0.2* | 67 | 19 | 43 | 5 |
TLC <5000** | 24 | 10 | 11 | 3 |
MicroESR >age in days +2 or >15 mm in 1st hour | 58 | 16 | 38 | 4 |
*Immature: Total neutrophil count, **TLC = Total leukocyte count.
Lethargy, refusal to feed, and respiratory distress were the most common symptoms. Sclerema was found in 21% of hypothermic babies. Of these, 76.2% were either moderately hypothermic or severely hypothermic (Table 4).
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Lethargy | 93 (53.8) | 24 (45.8) | 60 (51.7) | 9 (88.9) |
Seizures | 14 (57.1) | 4 (25) | 8 (62.5) | 2 (100) |
Jaundice | 6 (66.7) | 1 (100) | 4 (50) | 1 (100) |
Vomiting | 4 (50) | 1 (100) | 3 (33.3) | 0 (0) |
Respiratory distress | 34 (44.1) | 11 (9.1) | 20 (60) | 3 (66.7) |
Sclerema | 21 (80.9) | 5 (60) | 10 (80) | 6 (100) |
Peripheral cyanosis | 29 (48.3) | 6 (16.6) | 17 (47.1) | 6 (83.3) |
Pedal Edema | 16 (56.2) | 2 (50) | 19 (44.4) | 5 (80) |
Facial erythema | 6 (71.4) | 1 (100) | 3 (66.7) | 3 (100) |
Sluggish pupils | 48 (62.5) | 12 (58.3) | 32 (59.4) | 4 (100) |
Large pupils | 22 (45) | 9 (22.2) | 11 (45.5) | 2 (50) |
Small pupils | 26 (56.3) | 9 (44.4) | 15 (73.3) | 2 (100) |
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Lethargy | 93 (53.8) | 24 (45.8) | 60 (51.7) | 9 (88.9) |
Seizures | 14 (57.1) | 4 (25) | 8 (62.5) | 2 (100) |
Jaundice | 6 (66.7) | 1 (100) | 4 (50) | 1 (100) |
Vomiting | 4 (50) | 1 (100) | 3 (33.3) | 0 (0) |
Respiratory distress | 34 (44.1) | 11 (9.1) | 20 (60) | 3 (66.7) |
Sclerema | 21 (80.9) | 5 (60) | 10 (80) | 6 (100) |
Peripheral cyanosis | 29 (48.3) | 6 (16.6) | 17 (47.1) | 6 (83.3) |
Pedal Edema | 16 (56.2) | 2 (50) | 19 (44.4) | 5 (80) |
Facial erythema | 6 (71.4) | 1 (100) | 3 (66.7) | 3 (100) |
Sluggish pupils | 48 (62.5) | 12 (58.3) | 32 (59.4) | 4 (100) |
Large pupils | 22 (45) | 9 (22.2) | 11 (45.5) | 2 (50) |
Small pupils | 26 (56.3) | 9 (44.4) | 15 (73.3) | 2 (100) |
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Lethargy | 93 (53.8) | 24 (45.8) | 60 (51.7) | 9 (88.9) |
Seizures | 14 (57.1) | 4 (25) | 8 (62.5) | 2 (100) |
Jaundice | 6 (66.7) | 1 (100) | 4 (50) | 1 (100) |
Vomiting | 4 (50) | 1 (100) | 3 (33.3) | 0 (0) |
Respiratory distress | 34 (44.1) | 11 (9.1) | 20 (60) | 3 (66.7) |
Sclerema | 21 (80.9) | 5 (60) | 10 (80) | 6 (100) |
Peripheral cyanosis | 29 (48.3) | 6 (16.6) | 17 (47.1) | 6 (83.3) |
Pedal Edema | 16 (56.2) | 2 (50) | 19 (44.4) | 5 (80) |
Facial erythema | 6 (71.4) | 1 (100) | 3 (66.7) | 3 (100) |
Sluggish pupils | 48 (62.5) | 12 (58.3) | 32 (59.4) | 4 (100) |
Large pupils | 22 (45) | 9 (22.2) | 11 (45.5) | 2 (50) |
Small pupils | 26 (56.3) | 9 (44.4) | 15 (73.3) | 2 (100) |
. | All hypothermics No. (fatality%) . | Mild hypothermia No. (fatality%) . | Moderate hypothermia No. (fatality%) . | Severe hypothermia No. (fatality%) . |
---|---|---|---|---|
Lethargy | 93 (53.8) | 24 (45.8) | 60 (51.7) | 9 (88.9) |
Seizures | 14 (57.1) | 4 (25) | 8 (62.5) | 2 (100) |
Jaundice | 6 (66.7) | 1 (100) | 4 (50) | 1 (100) |
Vomiting | 4 (50) | 1 (100) | 3 (33.3) | 0 (0) |
Respiratory distress | 34 (44.1) | 11 (9.1) | 20 (60) | 3 (66.7) |
Sclerema | 21 (80.9) | 5 (60) | 10 (80) | 6 (100) |
Peripheral cyanosis | 29 (48.3) | 6 (16.6) | 17 (47.1) | 6 (83.3) |
Pedal Edema | 16 (56.2) | 2 (50) | 19 (44.4) | 5 (80) |
Facial erythema | 6 (71.4) | 1 (100) | 3 (66.7) | 3 (100) |
Sluggish pupils | 48 (62.5) | 12 (58.3) | 32 (59.4) | 4 (100) |
Large pupils | 22 (45) | 9 (22.2) | 11 (45.5) | 2 (50) |
Small pupils | 26 (56.3) | 9 (44.4) | 15 (73.3) | 2 (100) |
Hypoxia, shock and hypoglycemia were detected at admission in 47%, 15% and 35% respectively. The fatality was significantly increased when hypothermia was associated with hypoxia, shock or hypoglycemia (p = 0.033, p = 0.012, and p = 0.0249 respectively) (Table 5). When moderate hypothermia was associated with hypoxia or shock, the fatality was 83.3% and 90.9% respectively. Similarly, mild hypothermia with hypoglycemia was associated with 71.4% fatality.
. | All hypothermics No. (fatality %) . | Mild hypothermia No. (fatality %) . | Moderate hypothermia No. (fatality %) . | Severe hypothermia No. (fatality %) . |
---|---|---|---|---|
Abdominal skin temp. (°C) | 100 (51%) | 28 (39.3%) | 62 (51.6%) | 10 (80%) |
Hypothermic babies with hypoxia* | 47 (70.2%) | 16 (43.8%) | 24 (83.3%) | 7 (85.7%) |
Hypothermic babies with shock** | 15 (86.7%) | 2 (50%) | 11 (90.9%) | 2 (100%) |
Hypothermic babies with hypoglycemia# | 35 (65.7%) | 7 (71.4%) | 27 (62.9%) | 1 (100%) |
. | All hypothermics No. (fatality %) . | Mild hypothermia No. (fatality %) . | Moderate hypothermia No. (fatality %) . | Severe hypothermia No. (fatality %) . |
---|---|---|---|---|
Abdominal skin temp. (°C) | 100 (51%) | 28 (39.3%) | 62 (51.6%) | 10 (80%) |
Hypothermic babies with hypoxia* | 47 (70.2%) | 16 (43.8%) | 24 (83.3%) | 7 (85.7%) |
Hypothermic babies with shock** | 15 (86.7%) | 2 (50%) | 11 (90.9%) | 2 (100%) |
Hypothermic babies with hypoglycemia# | 35 (65.7%) | 7 (71.4%) | 27 (62.9%) | 1 (100%) |
*Spo2 < 90%, **CFT > 3 sec, #Blood sugar<47 mg% (WHO definition).
. | All hypothermics No. (fatality %) . | Mild hypothermia No. (fatality %) . | Moderate hypothermia No. (fatality %) . | Severe hypothermia No. (fatality %) . |
---|---|---|---|---|
Abdominal skin temp. (°C) | 100 (51%) | 28 (39.3%) | 62 (51.6%) | 10 (80%) |
Hypothermic babies with hypoxia* | 47 (70.2%) | 16 (43.8%) | 24 (83.3%) | 7 (85.7%) |
Hypothermic babies with shock** | 15 (86.7%) | 2 (50%) | 11 (90.9%) | 2 (100%) |
Hypothermic babies with hypoglycemia# | 35 (65.7%) | 7 (71.4%) | 27 (62.9%) | 1 (100%) |
. | All hypothermics No. (fatality %) . | Mild hypothermia No. (fatality %) . | Moderate hypothermia No. (fatality %) . | Severe hypothermia No. (fatality %) . |
---|---|---|---|---|
Abdominal skin temp. (°C) | 100 (51%) | 28 (39.3%) | 62 (51.6%) | 10 (80%) |
Hypothermic babies with hypoxia* | 47 (70.2%) | 16 (43.8%) | 24 (83.3%) | 7 (85.7%) |
Hypothermic babies with shock** | 15 (86.7%) | 2 (50%) | 11 (90.9%) | 2 (100%) |
Hypothermic babies with hypoglycemia# | 35 (65.7%) | 7 (71.4%) | 27 (62.9%) | 1 (100%) |
*Spo2 < 90%, **CFT > 3 sec, #Blood sugar<47 mg% (WHO definition).
Fatality was found to increase with increasing physiological derangements (Table 6). Hypothermia associated with other physiological derangements (hypoxia, shock, hypoglycemia) was found to have a higher fatality as compared to hypothermia alone (p = 0.0494).
. | No. . | No. expired . | Fatality % . |
---|---|---|---|
Hypothermia alone | 35 | 9 | 25.6 |
Hypothermia + hypoglycaemia | 14 | 6 | 42.9 |
Hypothermia + hypoxia | 22 | 12 | 52.1 |
Hypothermia + hypoglycemia + hypoxia | 14 | 11 | 78.57 |
Hypothermia + hypoglycemia + shock | 4 | 3 | 75 |
Hypothermia + hypoxia + shock | 8 | 7 | 87.5 |
Hypothermia + hypoglycemia + Hypoxia + shock | 3 | 3 | 100 |
100 | 51 | 51 |
. | No. . | No. expired . | Fatality % . |
---|---|---|---|
Hypothermia alone | 35 | 9 | 25.6 |
Hypothermia + hypoglycaemia | 14 | 6 | 42.9 |
Hypothermia + hypoxia | 22 | 12 | 52.1 |
Hypothermia + hypoglycemia + hypoxia | 14 | 11 | 78.57 |
Hypothermia + hypoglycemia + shock | 4 | 3 | 75 |
Hypothermia + hypoxia + shock | 8 | 7 | 87.5 |
Hypothermia + hypoglycemia + Hypoxia + shock | 3 | 3 | 100 |
100 | 51 | 51 |
. | No. . | No. expired . | Fatality % . |
---|---|---|---|
Hypothermia alone | 35 | 9 | 25.6 |
Hypothermia + hypoglycaemia | 14 | 6 | 42.9 |
Hypothermia + hypoxia | 22 | 12 | 52.1 |
Hypothermia + hypoglycemia + hypoxia | 14 | 11 | 78.57 |
Hypothermia + hypoglycemia + shock | 4 | 3 | 75 |
Hypothermia + hypoxia + shock | 8 | 7 | 87.5 |
Hypothermia + hypoglycemia + Hypoxia + shock | 3 | 3 | 100 |
100 | 51 | 51 |
. | No. . | No. expired . | Fatality % . |
---|---|---|---|
Hypothermia alone | 35 | 9 | 25.6 |
Hypothermia + hypoglycaemia | 14 | 6 | 42.9 |
Hypothermia + hypoxia | 22 | 12 | 52.1 |
Hypothermia + hypoglycemia + hypoxia | 14 | 11 | 78.57 |
Hypothermia + hypoglycemia + shock | 4 | 3 | 75 |
Hypothermia + hypoxia + shock | 8 | 7 | 87.5 |
Hypothermia + hypoglycemia + Hypoxia + shock | 3 | 3 | 100 |
100 | 51 | 51 |
Discussion
It is estimated that annually, about 17 million neonates develop hypothermia in the developing world.1 Sick or low birthweight babies admitted to neonatal units with hypothermia are more likely to die than those admitted with normal temperatures.13,14 In the present study, fatality was 39.3% in mildly hypothermic babies, 51.6% in moderately hypothermic babies and 80% in severely hypothermic babies. This is the first study correlating fatality with severity of hypothermia according to WHO classification.
According to WHO classification of hypothermia,13 the newborn with a body temperature of 36–36.4°C is under cold stress (mild hypothermia). A baby with a temperature of 32–35.9°C has moderate hypothermia while a temperature below 32°C is considered to be indicative of severe hypothermia. Mild hypothermia has been regarded as a cause for concern. Moderate hypothermia has been associated with danger to the neonate and warming the neonate is recommended. Severe hypothermia has been associated with grave outlook requiring urgent skilled care.
Although the WHO classification is based solely on temperature of the newborn, sickness is a frequent association with neonatal hypothermia. Physiological derangements like hypoxia, hypoglycemia and shock set up a perpetuating cycle with hypothermia. Hence, neonatal morbidities like birth asphyxia, sepsis and respiratory distress are important factors affecting the outcome in hypothermic neonates. However, the WHO classification of hypothermia does not take into account these easily assessable morbidities. The present study found a strong association of these clinical parameters in predicting fatality.
Severely hypothermic neonates are critically sick and known to require intensive care.13 However, in our study, even in mild and moderate hypothermia, the fatality was increased significantly in the presence of associated illness (birth asphyxia, neonatal sepsis and respiratory distress) and physiological derangements (hypoxia, hypoglycemia and shock). Similarly, mildly hypothermic neonates weighing less than 2000 g had 59.3% fatality. Hence, their mere presence should classify a hypothermic neonate to a higher category of severity.
The site of measurement of hypothermia is not specified in WHO classification. In the present study, body temperature was measured by abdominal skin temperature recorded with the help of a thermistor probe attached to the upper abdomen. This method has been shown to be representative of the core temperature, is reliable for the diagnosis of hypothermia1 and has been used in some of the earlier studies.1,3,4,15–19 As the abdominal skin does not vasconstrict, it can be used as an indicator of central temperature and is easier and safer than using the rectum.
To conclude, WHO classification of severity of hypothermia correlates with risk of fatality. However, it considers only body temperature to classify severity of hypothermia. The presence of weight less than 2000 g, associated illness (birth asphyxia, neonatal sepsis and respiratory distress) and physiological derangements (hypoxia, hypoperfusion and hypoglycemia) should be considered adverse factors in hypothermic neonates. Their presence should classify hypothermia in the next higher category of severity in WHO classification.
Key Messages
WHO classification of severity of hypothermia correlates with the risk of fatality.
The presence of associated illness (birth asphyxia, neonatal sepsis and respiratory distress), physiological derangements (hypoxia, hypoglycemia and shock) and weight less than 2000 g should be considered adverse factors in hypothermic neonates.
The presence of these adverse factors should classify hypothermia in the next higher category of severity in the WHO classification.
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Author notes
Departments of aPediatrics and bBiochemistry, Maulana Azad Medical College, New Delhi 110002, India
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