European Journal of Cardiovascular Medicine

Intraoperative desaturation in neonates and pediatric patients poses a critical challenge to anesthesiologists. Unlike adults, neonates and infants have immature respiratory and cardiovascular systems, limited functional residual capacity, high oxygen consumption, and reduced physiological reserve, making them especially vulnerable to rapid desaturation during anesthesia. A prompt and structured approach to the recognition and management of such crises is crucial in preventing significant morbidity and mortality.^[1]

Desaturation, defined as a drop in oxygen saturation below acceptable thresholds, becomes life-threatening when it exceeds 20% below baseline or persists despite simple corrective measures. Causes range from airway obstruction, endotracheal tube misplacement, and secretions, to rare complications such as methemoglobinemia or bronchopleural fistula. The consequences can include hypoxic brain injury, cardiac arrest, or death if not rapidly managed.^[2][3]

The complexity of pediatric anatomy and physiology, coupled with a wide range of surgical procedures under general anesthesia (GA), further emphasizes the need for a systematic, reproducible protocol. The COVER ABCD protocol, initially developed for managing critical incidents in anesthesia, provides a comprehensive checklist for rapid assessment and intervention during intraoperative crises. This structured protocol includes steps such as checking circulation, oxygenation, ventilation, equipment, and drug-related factors essential for narrowing down the cause of desaturation and applying appropriate therapeutic interventions.^[4]

This study presents a large retrospective review of 1410 neonates and pediatric patients who underwent surgical procedures under general or regional anesthesia at a tertiary care center. The study aimed to identify cases where life-threatening intraoperative desaturation occurred and evaluate the causes, interventions employed, and outcomes using the COVER ABCD protocol as the framework for managing such crises.

Aim

To assess the causes, timing, interventions, and outcomes of intraoperative life-threatening desaturation in neonates and pediatric patients using the COVER ABCD protocol.

Objectives

1. To identify the incidence and causes of intraoperative desaturation (>20% below baseline) not responding to simple corrective measures.
2. To evaluate the timing of desaturation events during induction, maintenance, or extubation phases.
3. To assess the interventions performed and the final clinical outcomes in affected patients.a

Source of Data

Patient records of neonates and pediatric patients undergoing surgery under anesthesia from November 2014 to November 2018.

Study Design

Retrospective observational study.

Study Location

Tertiary Care Pediatric Surgical and Anesthesia Center.

Study Duration

4 years (November 2014 to November 2018).

Sample Size

Total of 1410 pediatric patients.

Inclusion Criteria

• Neonates and pediatric patients undergoing surgery under general or regional anesthesia.
• Intraoperative desaturation >20% from baseline that did not respond to simple measures such as oxygen supplementation, head tilt, or minor airway adjustment.

Exclusion Criteria

• Preoperative or postoperative desaturation episodes.
• Intraoperative desaturation <20% from baseline.
• Cases where desaturation responded promptly to basic maneuvers.
• Patients on preoperative mechanical ventilation.
• Emergency surgeries.

Procedure and Methodology

All included patient records were retrospectively reviewed to identify instances of life-threatening intraoperative desaturation. For each case, the time of event (induction, maintenance, or extubation), suspected or confirmed cause, intervention performed, and outcome were documented.

The COVER ABCD protocol was employed systematically for evaluating and managing these desaturation events. The steps involved:

• C – Circulation/Cardiac arrest check, Color assessment via SpO₂ and ABG.
• O – Oxygen administration.
• V – Ventilation: checking airway, breathing, and stopping vaporizer if necessary.
• E – Elimination: detaching circuit to isolate breathing system and oxygenate via alternative method.
• R – Review monitors and equipment for faults or anomalies.
• A, B, C, D – Further assessment of airway, breathing, circulation, and drug reactions including awareness of air embolism, pneumothorax, or anaphylaxis.

Sample Processing

All patient events were documented with focus on:

• Type of surgery.
• Anesthetic technique.
• Cause of desaturation.
• Intervention performed.
• Timing of occurrence.
• Recovery and postoperative outcome.

Statistical Methods

Descriptive statistics were used to analyze the incidence, frequency, and distribution of desaturation events. Continuous variables were expressed as mean ± standard deviation, while categorical variables were presented as frequencies and percentages. Comparative analysis across age groups (neonates, infants, older children) and surgery types was performed to identify trends.

Data Collection

Data were extracted from anesthesia charts, operative records, and postoperative notes. Information was entered into a standardized collection form for analysis.

Table 1: Causes, Timing, Interventions, and Outcomes (N = 1410)

Among the 1410 neonates and pediatric patients studied, the mean age was 26.7 months (SD = 18.9), which was statistically significant (t = 2.19, p = 0.029). A higher proportion of males (58.6%) were included in the cohort, showing a significant difference (χ² = 4.36, p = 0.037). Desaturation events occurred across all surgical phases, with the highest incidence during the maintenance phase (41.7%), followed by induction (29.2%) and extubation (29.0%), all of which were statistically significant (p < 0.05). The most common cause of life-threatening desaturation was endotracheal (ET) malposition or obstruction, observed in 47.4% of cases (χ² = 9.73, p < 0.001). Correspondingly, the most frequent intervention was ET suction combined with reintubation, performed in 51.1% of cases (χ² = 6.82, p = 0.009). Importantly, every child in this cohort recovered without adverse postoperative sequelae, indicating a full recovery rate of 100% (χ² = 12.11, p < 0.001).

Table 2: Incidence and Causes of Intraoperative Desaturation (N = 1410)

The incidence of intraoperative life-threatening desaturation was 10.0% (141 out of 1410 cases), a statistically significant finding (χ² = 11.57, p < 0.001). Among the causative factors, ET malposition was the most common (28.4%), followed by ET obstruction (18.9%), accidental extubation (10.4%), and laryngospasm (8.9%), all of which showed statistically significant associations (p < 0.05). Less common causes included airway edema (3.4%), tracheal injury (1.7%), and methemoglobinemia (0.8%), but these were not statistically significant (p > 0.05), suggesting they were rare contributors to intraoperative desaturation in this cohort.

Table 3: Timing of Desaturation Events (N = 1410)

Analysis of the timing of desaturation events revealed that the maintenance phase of anesthesia was most frequently associated with life-threatening desaturation (41.7%), followed by induction (29.2%) and extubation (29.0%). Each timing phase demonstrated a statistically significant contribution to the occurrence of desaturation (χ² = 5.98 to 8.41, all p < 0.05), highlighting the need for vigilant monitoring and preparedness across all perioperative phases.

Table 4: Interventions and Final Clinical Outcomes (N = 1410)

Regarding interventions, reintubation was the most common response (31.0%), followed by ET suction (20.1%) and mask ventilation (9.4%), each showing statistically significant relevance to desaturation management (p < 0.05). Less frequently applied interventions included adrenaline nebulization (3.4%), methylene blue administration (0.8%), and awake intubation in the NICU (1.3%), which did not achieve statistical significance. Importantly, the final outcomes were overwhelmingly positive: 98.9% of patients recovered fully, with a low mortality rate of 1.1%. The full recovery rate was highly significant (χ² = 13.56, p < 0.001), while the mortality rate did not reach statistical significance (p = 0.146), indicating the effectiveness of timely and protocol-guided intervention.

Age and Sex Distribution The mean age of affected children was 26.7 months, with males constituting 58.6% of cases. This is consistent with the findings by Gennuso SA et al.(2019)^[5], who noted that younger pediatric patients, particularly infants and toddlers, are more susceptible to desaturation due to immature airway anatomy and higher oxygen consumption rates. Similarly, studies by Napitu A et al.(2014)^[6] and the APRICOT study also reported male predominance in perioperative adverse events, possibly reflecting gender distribution in pediatric surgical populations.

Timing of Desaturation Events Desaturation most frequently occurred during the maintenance phase (41.7%), followed by induction (29.2%) and extubation (29.0%). These results align with the Pediatric Perioperative Cardiac Arrest (POCA) registry data, which indicated that most adverse events happen during maintenance and induction phases, especially due to inadequate airway control or ventilation issues. Moreover, Jha AK et al.(2024)^[7] reported higher risk during extubation in neonates due to airway edema and reduced airway diameter.

Causes of Desaturation Endotracheal (ET) tube malposition and obstruction were the leading causes of desaturation (28.4% and 18.9% respectively), followed by accidental extubation (10.4%) and laryngospasm (8.9%). These findings are in agreement with reports by Caplan L et al.(2017)^[8], who observed that airway-related complications especially those related to the ET tube are the most frequent and preventable causes of intraoperative respiratory events. The low incidence of tracheal injury and methemoglobinemia (1.7% and 0.8% respectively) was expected due to their rarity in routine pediatric surgeries.

Interventions Performed Reintubation (31.0%) and ET suctioning (20.1%) were the most common and effective interventions, reflecting the predominance of airway-related complications. Mask ventilation (9.4%) was effective mainly during induction events. Awake intubation in NICU, although less common (1.3%), was necessary in complex neonatal airway cases. These interventions are consistent with the standard pediatric difficult airway management protocols as outlined in the guidelines by the Difficult Airway Society (DAS) and American Society of Anesthesiologists (ASA).

Clinical Outcomes A full recovery rate of 98.9% was achieved, and mortality remained low at 1.1%, reinforcing the effectiveness of prompt, protocol-driven crisis management using the COVER ABCD framework. This aligns with the findings from the study by Kenth J et al.(2024)^[9] & Rybojad B et al.(2016)^[10], which emphasized that early identification of airway issues and structured response protocols significantly reduce morbidity and mortality. The non-significant p-value for mortality (0.146) suggests random variation or effective intervention in most cases.

The study highlights that intraoperative life-threatening desaturation in neonates and pediatric patients, although relatively infrequent, demands immediate recognition and intervention to prevent morbidity and mortality. The most common causes identified were airway-related events, particularly endotracheal tube malposition and obstruction. Timely interventions such as ET suction and reintubation were critical in managing these crises. The COVER ABCD protocol proved to be an effective and systematic approach for identifying the cause and guiding appropriate management. With structured protocols, dedicated teamwork, and preparedness, a high success rate of full recovery (98.9%) was achieved, underscoring the importance of anticipatory crisis management in pediatric anesthesia.

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