Abstract:

Acute severe asthma, or status asthmaticus, can rapidly progress to life-threatening respiratory failure, particularly in patients who develop severe hypercapnia and acidosis. While endotracheal intubation and mechanical ventilation are standard in such cases, they are associated with high complication rates. Non-invasive ventilation (NIV), although controversial in asthma, has shown potential benefit in select patients. We present a case of a 38-year-old male with a history of poorly controlled asthma who presented with acute severe respiratory distress, altered sensorium, pH of 7.12, and PaCO₂ of 96 mmHg. The patient was initiated on NIV (BiPAP mode) along with aggressive bronchodilator therapy, corticosteroids, and supportive care. Over the next 5 days, the patient’s ventilation parameters improved significantly without the need for invasive mechanical ventilation. This case highlights the potential role of early NIV as a bridge therapy in carefully selected patients with acute severe asthma complicated by severe hypercapnic respiratory acidosis.

Keywords: Non-invasive ventilation, acute severe asthma, hypercapnia, respiratory acidosis, BiPAP, status asthmaticus, respiratory failure, case report

Introduction:

Asthma is a major global health concern, affecting over 260 million people worldwide and causing nearly 455,000 deaths annually, as reported by the World Health Organization (WHO, 2023). While most asthma exacerbations can be managed effectively with inhaled bronchodilators and corticosteroids, a small subset of patients progress to acute severe asthma—also referred to as status asthmaticus—characterized by respiratory failure, hypoxemia, and hypercapnia unresponsive to initial therapy. This condition requires urgent and often advanced respiratory support.¹

According to WHO guidelines and the Global Initiative for Asthma (GINA), patients presenting with life-threatening features such as silent chest, altered consciousness, exhaustion, and elevated PaCO₂ levels should be considered for immediate escalation of care, including ventilatory support. In such cases, invasive mechanical ventilation (IMV) is traditionally employed, especially when patients develop severe respiratory acidosis (pH < 7.25) and hypercapnia (PaCO₂ > 60–70 mmHg), or show signs of fatigue or altered mentation.

However, IMV in asthma carries considerable risk. The mechanically ventilated asthmatic lung is prone to dynamic hyperinflation, intrinsic positive end-expiratory pressure (PEEPi), barotrauma, and ventilator-associated complications, including pneumothorax and hypotension due to impaired venous return. These risks make it imperative to explore less invasive alternatives where feasible.² Non-invasive ventilation (NIV), particularly bilevel positive airway pressure (BiPAP), has emerged as a potential bridge therapy in managing respiratory failure in select patients with acute severe asthma. NIV helps reduce the work of breathing, improve alveolar ventilation, decrease hypercapnia, and possibly avert the need for endotracheal intubation. Though not explicitly recommended in all cases of status asthmaticus, GINA and other international guidelines acknowledge that NIV may be considered in an intensive care setting under close monitoring, especially in centers with adequate experience and patient selection criteria.

The WHO recognizes the importance of optimizing critical care interventions and reducing the burden of mechanical ventilation where possible, particularly in resource-limited settings where ICU beds and ventilators may be scarce (WHO, Oxygen therapy for children: a manual for health workers, 2016; Global report on effective access to assistive technology, 2022). Thus, effective use of NIV in asthma could play a vital role in improving outcomes without exposing patients to the risks of IMV.³

This case report presents a patient with acute severe asthma and profound hypercapnic respiratory acidosis (pH 7.12, PaCO₂ 84 mmHg), who was managed successfully with early application of NIV. Despite traditionally being viewed as a relative contraindication to NIV, the patient’s condition improved significantly without the need for intubation. This report aims to highlight the evolving role of NIV in the management of severe asthma and underscores the importance of individualized, closely monitored care in respiratory emergencies.⁴

Table: 1: Indications and Contraindications of Non-Invasive Ventilation

Indications	Contraindications
Moderate to severe respiratory distress with preserved consciousness and airway reflexes	Altered mental status
Hypercapnic respiratory acidosis (e.g., pH 7.25–7.35, PaCO₂ > 45 mmHg)	Inability to protect the airway
Inadequate response to medical therapy with ongoing hypoxemia	Hemodynamic instability
To avoid intubation in patients at high risk of ventilator complications	Severe hypoxemia not responsive to NIV
	Facial trauma or anatomical deformity preventing mask Seal
	Recent upper gastrointestinal surgery or bleeding
	Excessive respiratory secretions
	Failure to improve after initial NIV trial

Case Report:

A 73-year-old male patient, with a known history of bronchial asthma spanning several years, was also diagnosed with hypertension and type 2 diabetes mellitus, both under medical management. Additionally, he had underlying chronic kidney disease, likely secondary to his comorbidities. The patient had been relatively stable until approximately five days prior to hospital admission when he began experiencing progressive respiratory symptoms. Initially, the patient reported mild shortness of breath and intermittent wheezing, which he attributed to his usual asthma symptoms. However, over the subsequent days, his dyspnea worsened significantly, becoming persistent and severe enough to limit his daily activities. He experienced frequent episodes of chest tightness and coughing with sputum production. The family noted increased use of accessory muscles of respiration, nasal flaring, and an inability to lie flat without respiratory discomfort.

Concomitantly, the patient developed a high-grade fever peaking at 104°F, associated with chills, rigors, and generalized weakness, raising suspicion for an infectious etiology precipitating his respiratory deterioration. There was no reported history of chest pain or hemoptysis. As his respiratory distress intensified, he experienced episodes of confusion and lethargy, indicative of possible hypoxia and hypercapnia. There was also a noticeable reduction in urine output, which raised concerns about acute kidney injury complicating his pre-existing chronic kidney disease.

On presentation to the Emergency Medical Room on 26.07.2025, vital signs revealed tachypnea, hypoxia, and evidence of respiratory fatigue. Arterial blood gases confirmed severe type II respiratory failure with marked hypercapnia (pCO₂ 96.35 mmHg) and acidemia (pH 7.057). Electrolyte disturbances and metabolic acidosis were also noted, likely secondary to renal impairment and systemic illness. Given the critical state, he was promptly admitted to the High Dependency Unit for close monitoring and initiation of advanced respiratory support.

The clinical picture was consistent with an acute severe bronchial asthma exacerbation complicated by type II respiratory failure, mixed acidosis, and acute kidney injury on the background of chronic kidney disease, necessitating a multidisciplinary approach for management.

Table:2 Vitals and blood gas parameters on arrival to date of discharge

Date	pH	pCO₂ (mmHg)	Na⁺ (mmol/L )	K⁺ (mmol/L)	Ca²⁺ (mmol/L)	Cl⁻ (mmol/L)	Lactate (mmol/L)	Glucose (mmol/L)	pO₂ (mmHg)
26.07.2025 (Date Of arrival)	7.057 ↓	96.35 ↑	141.18	5.80 ↑	1.13 ↓	106.32 ↑	1.25	15.51	89.86
27.07.2025	7.066 ↑	82.72 ↓	137.07	5.65 ↑	1.03 ↓	106.91 ↑	1.09	10.45	103.32
28.07.2025	7.070 ↑	75.45 ↓	141.07	5.24 ↑	0.63 ↓	109.38 ↑	1.36	11.99	84.02
29.07.2025	7.209 ↑	68.87 ↓	145.23	4.15	0.86 ↓	106.80 ↑	1.63	8.66	82.36
30.07.2025	7.242 ↑	53.45 ↓	147.45 ↑	3.77	0.43 ↓	106.23 ↑	1.31	9.68	81.91
31.07.2025	7.337 ↑	50.82 ↓	140.04	4.70 ↑	1.01 ↓	108.59 ↑	1.78	13.81	94.58
01.08.2025 (Date of Discharge)	7.476 ↑	47.17 ↓	144.99	3.43	0.83 ↓	95.59 ↓	1.07	8.71	98.17

Discussion:

This case highlights the effective use of non-invasive ventilation (NIV), specifically bilevel positive airway pressure (BiPAP), in managing a 73-year-old male patient with acute severe bronchial asthma complicated by severe mixed acidosis and type II respiratory failure (T2RF). The patient’s presentation was complex due to multiple comorbidities, including hypertension, type 2 diabetes mellitus, and chronic kidney disease (CKD) with superimposed acute kidney injury (AKI), which increased the risks associated with invasive mechanical ventilation. Acute severe asthma can progress rapidly to respiratory failure due to airway obstruction, bronchospasm, and respiratory muscle fatigue, often leading to hypercapnic respiratory acidosis. Traditional management includes aggressive medical therapy with bronchodilators, corticosteroids, oxygen supplementation, and invasive ventilation when indicated. However, invasive ventilation is associated with significant risks, including ventilator-associated pneumonia, airway trauma, and increased ICU stay.⁵

In this patient, the initial arterial blood gas analysis showed severe respiratory acidosis with a pH of 7.057 and markedly elevated pCO₂ of 96.35 mmHg, indicative of severe hypoventilation and carbon dioxide retention. The presence of metabolic derangements with mixed acidosis further complicated the clinical scenario. Despite this, the patient maintained preserved consciousness and airway reflexes, making him a suitable candidate for NIV. Non-invasive ventilation offers several physiological benefits in such cases. BiPAP supports ventilation by reducing the work of breathing, improving alveolar ventilation, and facilitating carbon dioxide clearance, which was evident in the patient’s progressive normalization of ABG parameters over the subsequent days (pH improved to 7.476 and pCO₂ reduced to 47.17 mmHg by day 7). Moreover, NIV helps to avoid the complications related to endotracheal intubation, especially important in elderly patients with multiple comorbidities.⁶

The indications for NIV in this case aligned with the recognized criteria: moderate to severe respiratory distress with preserved airway reflexes, hypercapnic respiratory acidosis (pH between 7.25 and 7.35, pCO₂ > 45 mmHg), and inadequate response to conventional medical therapy with ongoing hypoxemia. Additionally, the aim was to avoid intubation due to the patient’s high risk of ventilator- related complications.⁷

Several contraindications to NIV were carefully monitored and excluded in this patient, such as altered mental status, inability to protect the airway, hemodynamic instability, and severe hypoxemia unresponsive to NIV. Regular monitoring ensured that the patient continued to meet the criteria for safe NIV use. Multidisciplinary management was crucial for this patient’s recovery. Close nephrology involvement helped manage AKI on CKD, electrolyte imbalances, and fluid status. Respiratory medicine specialists optimized bronchodilator and steroid therapies, while intensive care specialists provided vigilant monitoring of respiratory and hemodynamic status.⁸

Despite these encouraging results, it is important to recognize that NIV is not universally recommended for all asthma exacerbations due to variable evidence and patient factors. Patient selection, close monitoring, and prompt identification of NIV failure are critical. In this case, the patient’s preserved consciousness, hemodynamic stability, and cooperative status favored successful NIV application. Financial constraints led to the patient’s discharge against medical advice after clinical improvement, which underlines the importance of socio-economic factors in patient care continuity.⁹

In summary, this case reinforces that NIV is a valuable tool in the management of acute severe asthma complicated by hypercapnic respiratory failure and mixed acidosis when applied judiciously. It provides effective ventilatory support, potentially avoids intubation, and reduces associated morbidity and mortality in appropriately selected patients.

Conclusion

Non-invasive ventilation can be an effective and safe alternative to invasive mechanical ventilation in carefully selected patients with acute severe asthma complicated by hypercapnic respiratory failure and mixed acidosis. Early application, close monitoring, and multidisciplinary management are key to improving outcomes and avoiding intubation-related complications. This case supports the growing evidence for the judicious use of NIV in acute severe asthma.¹⁰

Conflict of Interest:

No potential conflict of interest relevant to this article was reported

Authors of this Article

• Md. Mohiuddin Majed Chy, MBBS, MD, Consultant (ICU), Chittagong Medical College & Hospital
• Md. Imtiaz Ahmed, MBBS, RMO (ICU), Labaid Specialized Hospital Chattogram
• Abhimanyu Sen, MBBS, RMO (ICU), Labaid Specialized Hospital Chattogram
• Muhammad Mainuddin Murshed, MBBS, MPH, UHFPO (Eidgaon, Cox’s Bazar)
• KM Baki Billah, MBBS, MCPS, MD, Professor, Department of Anesthesia, Pain and Palliative & Intensive Care. Chittagong Medical College & Hospital

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