Study Design

Reduced Quality Factors

0 = no serious, - = serious,

- - = very serious

Positive Quality Factors

0 = none, + = one, ++ = multiple

Dichotomous Outcome Summary

Non-Dichotomous Outcome Summary

Brief description

Overall Quality

High, moderate, low,
very low, none

No of studies

Study Type

RoB

Indirectness

Imprecision

Inconsistency

Large Effect

Dose-Response

Confounder

# Intervention with Outcome

# Control with Outcome

RR (95% CI)

Outcome: Survival to discharge

5

OBS

- -

-

-

0

0

0

0

Very low

Outcome: Favorable neurologic outcome

5

OBS

-

-

-

0

0

0

0

Very low

Outcome: Hospital length of stay, histopathologic damage

0

NA

N/A

Introduction

Many newborns born without a heartbeat have experienced an indeterminate period of ischemia prior to birth and initiation of CPR. This potential for extended periods of a hypoxic-ischemic state prior to initiation of resuscitative efforts introduces variability and uncertainty regarding the usefulness of CPR efforts in newborns as a group. Certainly, there is a group of newborns for which the intrauterine period of hypoxia is brief enough that resuscitation at birth can lead to good outcomes, and so initiating CPR on individuals born without a heartbeat is reasonable in many cases. In addition, the rescuer does typically not know which newborns have potential for a good outcome at birth. Additionally, longer periods of the low-flow state experienced during CPR are associated with worse outcomes due to lack of adequate oxygen delivery to vital tissues such as the brain and heart.

Historically, ILCOR recommendations have stated that it is reasonable to consider stopping resuscitative measures if a newborn’s heartbeat remains undetectable for ≥ 10 minutes after birth.[ Perlman 2010] However, more recent information shows that some individuals survive with good neurologic function if high-quality resuscitative measures continue despite remaining pulseless at ≥ 10 minutes, and updated human guidelines suggest individualizing the decision of when to terminate resuscitation if the newborn remains pulseless at ≥ 10 minutes.[ Perlman 2015; Wyckoff 2020] The prognosis for survival with favorable neurologic outcome in newborn puppies and kittens undergoing CPR for more than 10 minutes at birth is unknown.

Consensus on science

Outcome 1: Survival to discharge

For the most critical outcome of survival to discharge, we identified 5 observational studies (very low quality of evidence, downgraded for very serious risk of bias, serious indirectness, and imprecision) that addressed the PICO question.[Steiner 1975, 1903; Patel 2004, 1902; Kasdorf 2015, 1904; Sproat 2017, 1901; Shibasaki 2020, 1907] Steiner et al. reported a single-center case series of 22 newborn infants with perinatal arrest, 14 of which occurred in the delivery room setting; 3 of these 14 infants underwent CPR for ≥ 10 minutes, and 2/3 survived beyond 1 and 2.5 years of age, respectively.[ Steiner 1903] Sproat and others reported a series of 87 newborns infants with no audible heart beat for the first 10 minutes of life (median time to heart beat 16 min, range 10 – 35 min). Of the 87 infants, 8 (9%) were alive at 2 years of age.[ Sproat 1901]

The 3 other studies suffer from very serious risk of bias for this outcome based on selection criteria because only newborns that achieved ROSC were included; the survival results follow here. Patel et al. presented a case series of 29 full-term newborn infants with Apgar 0 (no detectable heartbeat) from birth to ≥ 10 minutes of life; median time to heartbeat was 15 min (range 11 – 40 min) and all cases included were successfully resuscitated at their birth hospital and were then presented at one of the study group’s tertiary referral facilities. Therefore, overall survival cannot be determined from this study, but of the 29 infants included, 9 (31%) survived to hospital discharge. [Patel 1902] Kasdorf et al. compiled cases from 4 prior clinical trials (n = 81) and added 9 author institution cases of newborns with an Apgar score 0 at 10 minutes that either were (n = 56) or were not (n = 34) managed with therapeutic hypothermia. Hypothermia being the study intervention, all included newborn infants had achieved ROSC to be enrolled in the therapeutic hypothermia trials. Overall mortality for babies with an Apgar score of 0 at 10 min who also lived to participate in the cooling trials was 45/90 (50%) at 18 months of age.[ Kasdorf 1904] Finally, a study by Shibasaki et al. in term newborn infants (n=28) that had experienced an Apgar of 0 at 10 minutes after birth and were enrolled in a cooling study, reported a survival rate of 68% (19/28) at ≥ 18 months of age.[ Shibasaki 1907] These 3 studies would all overestimate the likelihood of survival in newborns with Apgar 0 at 10 minutes of age because only babies that achieved ROSC were included.

Outcome 2: Favorable neurologic outcome

For the critical outcome of favorable neurologic outcome, we identified 5 observational studies (very low quality of evidence, downgraded for serious risk of bias, serious indirectness, and imprecision) that addressed the PICO question.[ Steiner 1975, 1903; Patel 2004, 1902; Kasdorf 2015, 1904; Sproat 2017, 1901; Shibasaki 2020, 1907] These were the same studies already cited for the outcome of survival to hospital discharge. In the study by Steiner et al., the newborn infants that did survive, did so with good neurologic outcomes beyond 1 and 2.5 years of age, respectively.[ Steiner 1903] In the study by Sproat and colleagues that included 87 newborn infants that had no detectable heart beat for at least 10 minutes after birth, 5 of the 9 surviving infants were neurodevelopmentally normal at ~2 years of age.[ Sproat 1901] In the study by Patel et al. 8 of the 9 surviving infants (89%) experienced severe disability and 1/9 (11%) had moderate disability.[ Patel 1902] Kasdorf et al. found that of 90 newborn infants enrolled in the study, 27% (15/56) of those treated with hypothermia and 21% (7/34) in the normothermia group were neurologically normal at 18-24 months. Thus, overall 22/90 (24%) of the newborns that achieved ROSC following ≥ 10 minutes of CPR achieved a good long-term neurologic outcome.[ Kasdorf 1904] The study by Shibasaki et al. found that of the 19 infants that survived to ≥ 18 months of age, 16 (84%) had severe disability based on psychological, motor, intelligence scales while 3 (16%) had normal neurologic outcome.[ Shibasaki 1907]

Outcomes 3 and 4: Length of hospital stay or histopathologic damage

For the important outcomes of length of hospital stay and histopathologic damage, no studies were identified.

Treatment recommendation

In newborn puppies and kittens receiving chest compressions, we suggest continuation of CPR for at least 15 minutes before abandoning resuscitation efforts, as long as such efforts do not detract from necessary care of littermates with a better prognosis.(weak recommendation, very low quality of evidence)

Justification of treatment recommendation

Case series in newborn infants have shown that survival with good neurologic outcome is possible even in babies with no heartbeat for 10 or more minutes after birth. Particularly considering the relatively lesser executive function expected from dogs and cats compared to people, survival with the opportunity to achieve adequate neurologic function was considered the most critical outcome. Reported numbers in the less biased populations are small: 2/3 newborns survived in one small case series [Steiner 1903] while 8/87 (9%) survived in another. [Sproat 1901]. Such survival likelihood is similar to that for CPR in adult small animals, so it seems reasonable to pursue.

No evidence was found in newborn puppies and kittens, and many studies were biased because cases were selected from post-resuscitation study populations, which likely biases the results of those studies toward survival. Indeed, for infants that lived long enough to be enrolled in a cooling trial, survival to discharge was found to be 31% in one trial, and the two studies that followed babies to ≥ 18 months found survival of 50% and 68%. These high survival frequencies are unlikely in the general population of newborn puppies and kittens requiring resuscitation because every newborn infant enrolled in these studies had already achieved ROSC.

Moreover, the committee chose to suggest continuing CPR efforts in newborn puppies and kittens without spontaneous circulation for at least 15 minutes after birth, as long as such efforts do not detract from necessary care of littermates with a better prognosis. Other factors may influence the decision to perform CPR and its duration, including presence of obvious, severe congenital abnormality or clear signs of death (e.g., anasarca, depilation). As for in newborn infants,[Wyckoff 2020] the decision to discontinue resuscitative efforts should be undertaken with both clinical team and pet owner goals in mind.

Knowledge gaps

It is important to better delineate what the survival rate, functional outcome and level of post-resuscitation care are in newborn puppies and kittens that undergo incremental durations of CPR.