Hypothermia

Rewarming the neonate is an important first step in care, as hypothermia inhibits gastric motility and causes bradycardia, which may eventually result in a decreased respiratory rate and cardiovascular collapse.¹² Normal neonatal temperatures range from 95 to 99 F (35 to 37.2 C).^9,15 Hypothermic neonates need to be slowly warmed to a rectal temperature of 97 to 98 F (36.1 to 36.6 C) over a period of one to three hours. Rewarming too rapidly increases the neonate's metabolic demand, which can cause pulmonary and circulatory collapse.³

You can use several methods to warm a hypothermic neonate, but an infant incubator is ideal.¹⁵ The ideal ambient temperature is 85 to 90 F (29.4 to 32.3 C).¹⁵ Other sources such as warm-water circulating pads, microwaved rice bags, warm-water bottles, warm towels, and infrared heat lamps can be used, but take extreme care to ensure that the neonate is not overheated or burned. It has been suggested to place a warm-water circulating pad on the ceiling of the cage to create a warmer environment.¹⁴ Establish a temperature gradient, allowing neonates to be able to move away from the heat source¹⁴ to prevent hyperthermia.

Normal blood glucose concentrations in neonatal animals are 90 to 140 mg/dl.¹³ Hypoglycemia usually results from inadequate or infrequent feedings. A puppy can survive 24 hours and maintain normal blood glucose concentrations through glycogenolysis and gluconeogenesis,²⁴ but has used most of the substrates for gluconeogenesis by this point and the blood glucose concentration can drop precipitously. Disease processes such as sepsis can also result in hypoglycemia.

Clinical signs of hypoglycemia, which can also be the result of processes other than hypoglycemia, include muscle tremors, seizures, lethargy, depression, collapse, and coma; death may also occur.¹³ Intravenous or intraosseous dextrose is the ideal treatment until the neonate is capable of feeding (normothermic and well-hydrated). Examples of intravenous doses include 10% dextrose solution at 1 to 2 ml/kg intravenously or intraosseously¹³ and 10% dextrose solution at 2 to 4 ml/kg intravenously or intraosseously as a slow bolus.¹⁵ The dose depends on the severity of hypoglycemia. The goal is to maintain the animal's blood glucose concentration in the normal range.

Sepsis

Antibiotics are often administered empirically to neonates that may have sepsis. Consider these drugs when a neonate is as stable as possible. Antibiotics that are safer to administer to neonates include cephalosporins, penicillins, clavulanic acid, macrolides, and trimethoprim-sulfonamide.¹⁹ Penicillins are recognized as one of the safer antibiotics because of their broad dose range and are often used as a first choice.¹²

Antibiotics to avoid in neonates are aminoglycosides (renal damage and ototoxicosis), tetracyclines (dental damage), chloramphenicol (bone marrow suppression), and quinolones (cartilage damage).¹²

Necropsy

If a puppy or kitten does not survive, perform a necropsy or have one performed by a veterinary pathologist. A bacterial (e.g. streptococcus) or viral (e.g. herpesvirus) cause may be found. A necropsy does not always provide the answer, but the results may direct a more specific treatment plan for surviving littermates.

CONCLUSION

Neonates that need critical care can be treated successfully, but the physiologic differences between adults and neonates must be recognized in order to institute the most successful therapy. Once the emergency stage has passed, careful monitoring for hypoxia, hypothermia, hypoglycemia, and dehydration must continue to ensure the best chance of survival for the neonate. Additional treatments should begin after the animal is as stable as possible. Although not every puppy and kitten will be saved, a higher percentage of survival can be ensured when an intensive treatment effort is made.

Olivia Wilson, DVM
Tigard Animal Hospital
13599 Southwest Pacific Highway, Suite C
Tigard, OR 97223

Mushtaq A. Memon, BVSc, PhD, DACT
Department of Veterinary Clinical Sciences
College of Veterinary Medicine
Washington State University
Pullman, WA 99164