Heart Rate Assessment in Neonatal Resuscitation: Methods and Clinical Decision Points

Heart rate (HR) is widely regarded as one of the most reliable indicators of physiological status in newborn puppies and kittens. During the immediate postnatal period, HR reflects the adequacy of oxygenation and perfusion. The RECOVER guidelines recommend using HR as a primary parameter to guide resuscitation decisions, particularly when determining the need for ventilation or escalation to advanced interventions^1,2. 

Understanding Heart Rate Thresholds in Practice¹ 

Specific HR thresholds are used to guide clinical decision-making during neonatal resuscitation: 

• HR >120 beats per minute: May indicate adequate oxygenation and transition 

• HR <120 beats per minute: May suggest compromised status requiring ventilatory support 

• HR <50 beats per minute or absent: May indicate the need for cardiopulmonary resuscitation (CPR) 

These thresholds should not be interpreted in isolation but rather in conjunction with respiratory effort and overall clinical presentation. 

Methods for Assessing Heart Rate¹ 

Several techniques may be used to assess HR in neonatal patients. The choice of method often depends on clinical setting, equipment availability, and the condition of the neonate. 

Auscultation 

Auscultation using a stethoscope is commonly employed due to its practicality and speed. It allows direct assessment of cardiac activity and is often sufficient in most clinical scenarios. 

Palpation 

Palpation of the apex beat may be attempted, although it can be challenging in small or compromised neonates. This method may be less reliable compared to auscultation. 

Electrocardiography (ECG) 

ECG provides continuous and accurate HR monitoring. However, its use may be limited during the initial resuscitation phase due to time constraints and equipment availability. 

Doppler Ultrasound 

Doppler devices may assist in detecting cardiac activity and measuring HR, particularly when other methods are inconclusive. 

Limitations of Pulse Oximetry 

Pulse oximetry is not considered a reliable standalone method for HR assessment in neonates. It may provide delayed or inaccurate readings, especially in compromised patients^1,2. 

Interpreting Heart Rate in Clinical Context 

Heart rate should always be interpreted alongside other clinical parameters. For example, a neonate with an HR above 120/min but inadequate respiratory effort may still require intervention. 

Bradycardia in newborns is often secondary to hypoxemia rather than intrinsic cardiac dysfunction. Therefore, addressing the underlying cause, typically inadequate ventilation, is considered a priority over pharmacologic intervention¹. 

Dynamic Changes During Resuscitation¹ 

Heart rate in neonates may change rapidly in response to interventions. Effective ventilation, particularly positive pressure ventilation (PPV), may lead to a prompt increase in HR, indicating improved oxygenation. 

Conversely, persistent bradycardia despite intervention may suggest inadequate ventilation, airway obstruction, or the need for escalation to advanced resuscitative measures. 

Guiding Clinical Decisions 

The guidelines recommend using HR as a trigger for initiating or modifying interventions: 

• Initiate PPV if HR remains below 120/min 

• Escalate to CPR if HR remains below 50/min 

• Continue monitoring if HR improves with intervention 

Timely decisions based on HR assessment may reduce delays in care and improve the likelihood of successful resuscitation. 

Practical Considerations for Veterinary Teams 

In clinical practice, rapid and accurate HR assessment is essential. Veterinary teams should be familiar with multiple assessment methods and be prepared to adapt based on the situation. 

Preparation, including availability of appropriate equipment and training in assessment techniques, may enhance efficiency during resuscitation. 

Conclusion 

Heart rate assessment is a cornerstone of neonatal resuscitation in puppies and kittens. By combining accurate measurement with clinical context, veterinarians may make informed decisions that support effective intervention. Continuous reassessment and timely response to changes in HR are essential components of successful neonatal care. 

Reference 

1. Boller M, Burkitt‐Creedon JM, Fletcher DJ, Byers CG, Davidson AP, Farrell KS, Bassu G, Fausak ED, Grundy SA, Lopate C, Veronesi MC. RECOVER Guidelines: Newborn Resuscitation in Dogs and Cats. Clinical Guidelines. Journal of Veterinary Emergency and Critical Care. 2025 Aug;35:S60-85. https://onlinelibrary.wiley.com/doi/pdf/10.1111/vec.70013 
2. Murphy MC, De Angelis L, McCarthy LK, O’Donnell CP. Comparison of infant heart rate assessment by auscultation, ECG and oximetry in the delivery room. Archives of Disease in Childhood-Fetal and Neonatal Edition. 2018 Sep 1;103(5):F490-2. https://www.researchgate.net/profile/Madeleine-Murphy-2/publication/325372531_Comparison_of_infant_heart_rate_assessment_by_auscultation_ECG_and_oximetry_in_the_delivery_room/links/613bb37c01846e45ef3e328b/Comparison-of-infant-heart-rate-assessment-by-auscultation-ECG-and-oximetry-in-the-delivery-room.pdf