Shayam L. Kaushik
Neehim Grover
V.R. Parmar
Rajni Kaushik
Anmol K. Gupta
From
the Department of Pediatrics, Indira Gandhi
Medical College, Shimla 171 001, India.
Reprint requests: Dr. (Mrs.) Neelam Grover, IV!2, Richmond Estate, Shimla 171 001, India.
Manuscript received: February 25, 1997;
Initial review completed: April 7, 1997;
Revision accepted: February 26, 1998.
Neonatal hypothermia has been shown to be prevalent even in the tropical climates of developing countries and is a potentially greater hazard in the colder mountaineous region particularly in winters(1,3). This fact is borne out by the studies relating higher incidence of neonatal hypothermia to nocturnal winter temperatures(4,5). Neonates;
i
particularly low birth weight (LBW),
I
preterm and small for date (SFD) babies,
are most susceptible and sensitive to hypothermia due to immaturity of their thermo-
!
regulatory mechanism(6,7). A high altitude
F
with cold weather prevailing all around the
year leads not only to increased incidence but also profound and prolonged hypothermia in newborns in a shorter period of exposure inspite of its awareness and traditional practices prevailing among masses in this region to prevent it(8). The current communication presents our experience with neonatal hypothermia.
Subjects and Methods
The present study was conducted in the Neonatology Unit of the Department of Pediatrics and Kamla Nehru Hospital (KNH), Indira Gandhi Medical College, Shimla.
The study was carried out from July 1994 to June 1995 for one year
to include all seasons. All consecutive live births at KNH in this duration were included in the study. Outborn babies admitted with hypothermia were not included in the study. Hypothermia was defined as skin (axillary) temperature of less than 35°C(9).
Axillary temperature of all babies born at KNH was recorded within one hour of
birth and then 12 hourly till discharge.
Mothers were an active participant in recognizing hypothermia by touching the skin of feet and abdomen of the baby(10) and bringing it to the notice of resident on duty who further confirmed it by axillary
temperature of < 35°C. Babies found to be hypothermic (axillary
temperature < 35°C) were admitted to newborn unit in the Department of Pediatrics and managed under radiant warmer/incubator. Temperature of these babies were recorded hourly till stabilized. Low reading thermometer (recording upto 22°C) was used for it. Depending upon the axillary temperature babies were grouped as follows: (i) Hypothermia: 32°C to < 35°C; and (ii) Severe hypothermia: <32°C.
Transportation of hypothermic babies from obstetrical unit at KNH to newborn nursery at IGMC, Shimla (6-7 km) was done by Ambulance/Private Vehicle after
wrapping them in. cotton and covering by blanket. Sometimes during snowfall when vehicles did not ply, transportation. was done on foot. Summer was counted from April to September and winter from October to March.
Babies were found hypothermic either in operation theatre, labor
room or in the maternity ward. The ambient temperature of
operation theatre, labor room and maternity ward during the study
period remained between 15°C-26°C. The temperature of the newborn nursery where the hypothermic babies were managed was maintained "between 28°C-32°C.
Investigations done in all the hypothermic babies were blood culture, sepsis screen, serum electrolytes, blood sugar and X-ray chest. Ultrasound and CT Scan of head were done only in those babies who were suspected to have intracranial bleed.
Data so collected was fed in the computer and subjected to statistical analysis using chi-square test.
Results
During one year study period, there were 2063 live births and 59 (2.9%) of these developed hypothermia. The incidence of hypothermia was observed to vary with seasons being significantly higher in winter. From October to March (winter) the incidence was 3.9% (38/953) as compared to 1.9% (21/1110) from April to September (summer) [p < 0.005]. Hypothermia was found to be
significantly higher amongst LBW, preterm and SFD babies (Table 1).
Hypothermia was detected in babies while they were in operation theatre (n
= 11), labour room (n = 18) and maternity ward with mothers (n
=
26). Four of the babies developed hypothermia after the discharge from hospital and they were readmitted in the newborn nursery.
Clinical features and biochemical abnormalities found in babies with hypothermia and/or other morbidity are shown in Table II. The average time taken for correction of hypothermia in those babies who re- covered from hypothermia was 5 hours (3- 8 hours).
The first 24 hours of life were observed to be critical for maintaining the body
temperature as the maximum cases of hypothermia (n
=
47) were seen within this period.
Birth asphyxia requiring active resuscitation was associated with 51 % (n
=
30) cases
of hypothermia and 18.6% (n
=
11) had septicemia.
TABLE
I
Incidence
of Hypothermia
(%) by Birth
Weight,
Gestation and Gestational Category.
|
Variable
|
Total
live births |
Hypothermia
(%) |
X2
(p) |
OR
(95% CI) |
|
Birth weight
|
|
< 2500 g |
573 |
48 |
(8.4) |
87.04 |
12.29 |
|
≥2500 g |
1490 |
11 |
(0.7) |
« 0.001) |
(7.3 - 20.8) |
|
Period of gestation
|
|
< 37 week |
277 |
41 (14.8) |
164.27 |
17.06 |
|
≥37 week |
1786 |
18 |
(1.0) |
(< 0.001) |
(11.1- 26.3) |
|
Gestational category*
|
|
SFD (<
- 2SD)
|
148 |
24 (16.2) |
102.4 |
10.39 |
|
AFD |
1897 |
35 |
(1.9) |
(< 0.001) |
(6.6 -16.4) |
* 18 of the babies were large for date and none of these developed hypothermia.
SFD
-
Small for date, AFD
-
Appropriate for date.
TABLE
II
Clinical Features and Biochemical Abnormalities in Babies With Hypothermia (n = 59).
|
Clinical features |
n |
(%) |
Biochemical abnormality |
n |
(%) |
|
Apathy
I
Lethargy |
59 |
(100) |
Hypoglycemia |
9 |
(15.3) |
|
Refusal to feed |
59 |
(100) |
Hypoglycemia |
4 |
(6.8) |
|
Coldness to touch |
59 |
(100) |
Acidosis |
12 |
(20.3) |
|
Immobility |
38 |
(64.4) |
Hyperbilirubinemia |
6 |
(10.2) |
|
Redness of face & extremities |
19 |
(32.2) |
Hyponatremia |
2 |
(3.4) |
|
Bradycardia |
44 |
(74.6) |
|
|
|
|
Apnea |
8 |
(13.6) |
|
|
|
|
Seizures |
5 |
(8.5) |
|
|
|
|
Sclerema |
4 |
(6.8) |
|
|
|
|
Oliguria |
6 |
(10.2) |
|
|
|
|
Edema |
7 |
(11.9) |
|
|
|
|
Severe hypothermia* |
16 |
(27.1) |
|
|
|
There were 73 neonatal deaths during
the study period and primary causes of neonatal death were asphyxial conditions
(n
=
23), infections (n = 17), immaturity (n = 13), hypothermia (n = 7), congenital malformation (n
=
1) and' miscellaneous (n
=
12). Hypothermia alone contributed to 6.9% (n
=
7) of all neonatal deaths, besides 9 of the newborns who died due to birth asphyxia, 8 with immaturity, 4 with infections and 2 with miscellaneous conditions also had hypothermia in addition to the primary morbidities. In all 59 of the babies who suffered from hypothermia with or without other illnesses 51 % (n
=
30) died.
Discussion
Neonatal hypothermia has been re- ported at the institutional
level in some developing countries including India (11,12). The
dual factors influencing hypothermia are disorders of body's
thermoregulatory mechanism and low environmental temperature. There is a higher incidence of neonatal cold injury in winter nights and in winter months(4,5,13). In our study, the overall incidence of hypothermia was high (2.9%) against 1.9% reported from New Delhi(12). A significantly higher incidence of hypothermia amongst neonates during winter is also in conformity with earlier experience(13).
It is well documented fact that birth weight and gestational age have an important bearing on incidence and associated mortality due to hypothermia(9). In our study the incidence as well as mortality due to hypothermia was higher in LBW babies. Our study confirmed the association between birth asphyxia and hypothermia (51%) as most of these babies required active resuscitation and hence prolonged exposure.
Overall 51 % of mortality amongst hypothermic neonates is comparable to 56.2%
reported from North India(13). Hypothermia contributed to 9.6% of total neonatal deaths in contrast to 1.4% from Varanasi(11). This could be related to cold weather round the year and time for transportation of sick babies from KNH to Pediatric Ward.
In conclusion, the incidence as well as mortality due to hypothermia was significantly higher amongst LBW, perterm and SPD
babies and in babies having other associated illnesses. The first
24 hours of birth were found to be critical for the development of
hypothermia. A significant seasonal variation with higher incidence of hypothermia during winter is also reflected in the study. Hypothermia is an important
cause of preventable morbidity and mortality amongst neonates. The incidence of hypothermia can be lowered by providing effective warming facility in the labor room, operation theatre and during the transportation of sick neonates.
