Use of Non-Invasive Ventilation in ICU to Reduce the Incidence of Invasive Mechanical Ventilation.

In the intensive care unit (ICU), one of the most common and difficult conditions is acute respiratory failure.¹ It can be brought on by a variety of conditions, including acute respiratory distress syndrome (ARDS), pneumonia, acute cardiogenic pulmonary edema, abrupt aggravation of chronic obstructive pulmonary disease (COPD), neuromuscular issues, and other severe disorders.^2,3 In order to maintain proper breathing and oxygenation, patients with respiratory failure frequently need respiratory support.^4,5 Endotracheal intubation and invasive mechanical ventilation (IMV) may be required and potentially life-saving in severe circumstances.⁶ However, ventilator-associated pneumonia, airway trauma, ventilator-induced lung injury, hemodynamic disturbances, increased sedation requirements, delirium, extended ICU stay, and complications associated with challenging or protracted weaning are also linked to invasive mechanical ventilation.^7,8 Thus, avoiding needless intubation while preserving sufficient respiratory support continues to be a key goal of critical care treatment.⁹

Non-invasive ventilation (NIV) has evolved as a valuable approach to delivering ventilatory support without the use of an artificial airway.¹⁰ Using an external interface—typically a nasal, oronasal, or full-face mask—NIV provides positive-pressure breathing. Bilevel positive airway pressure ventilation and continuous positive airway pressure (CPAP) are the two main types of NIV.^11,12 NIV can enhance alveolar ventilation and gas exchange, lessen respiratory muscle workload, lessen dyspnea, and enable worn-out respiratory muscles to recuperate by supplying positive airway pressure and inspiratory assistance.^13,14 While receiving respiratory support, NIV typically permits patients to be conscious, communicate, cough, and swallow while maintaining their natural airway processes, in contrast to invasive ventilation.¹⁵

Even with these advantages, not all patients benefit from NIV. Proper patient selection, the severity and cause of respiratory failure, the timing of NIV beginning, the right interface selection, proper ventilator settings, patient participation, and ongoing monitoring are some of the variables that affect the result.¹⁶ Endotracheal intubation may be delayed and have unfavorable consequences if a patient's condition is not recognized. Therefore, the goal of NIV should be to minimize needless or preventable invasive ventilation while guaranteeing prompt intubation when clinically warranted, rather than to prevent invasive mechanical ventilation in every patient.¹⁷

For achieving good NIV, healthcare professionals are crucial. Early detection of improvement or decline is made possible by ongoing monitoring of respiratory rate, oxygen saturation, work of breathing, consciousness level, hemodynamic condition, mask tolerance, skin integrity, and blood gas parameters. NIV adherence and patient comfort can both be enhanced by appropriate nurse care.¹⁸

In order to ascertain its role in lowering the prevalence of preventable intrusive mechanical ventilation, it is crucial to look at the usage of non-invasive ventilation in intensive care unit patients. Increased knowledge of suitable indications, monitoring needs, NIV failure predictors, and prompt escalation of respiratory support may encourage safer and more efficient NIV use, lessen complications from needless intubation, and enhance the standard of care for critically ill patients. Therefore, the current study aims to evaluate the effectiveness of a standardized NIV protocol in reducing the frequency of invasive mechanical ventilation among ICU patients with acute respiratory failure in adults.

This was a retrospective cohort study. After receiving approval from the Ethical Review Committee, research was carried out for six months, from June 2025 till  December 2025, at the adult medical ICU of Shaukat Khanum Memorial Cancer Hospital and Research Centre. The study included 27 patients who received NIV. With a 9% margin of error, a 95% confidence interval, and the expected frequency of IMV in patients who received NIV as 5.9%¹⁸, a sample size of 27 patients was estimated. The method of non-probability consecutive sampling was applied.

Inclusion criteria: Patients of age 18 years, admitted to the adult ICU with a primary diagnosis of acute respiratory failure (hypoxemic, hypercapnic, or mixed) requiring advanced ventilatory support, who were initiated on NIV within 24 hours of ICU admission  were included. Additionally, only those cases with availability of sufficient data in the electronic record to determine ventilatory strategy and main outcomes were included.

Exclusion criteria: Patients admitted for elective postoperative monitoring without acute respiratory failure; patients with a documented do not intubate (DNI) or comfort measures only order at or within 24 hours of ICU admission; those with preexisting tracheostomy or chronic home mechanical ventilation dependence at the time of admission; patients with immediate cardiac arrest, massive trauma, or other conditions in which the primary indication for intubation was nonrespiratory (e.g., severe head injury, ongoing seizures, or coma from nonrespiratory causes); patients transferred from another ICU with more than 24 hours of prior invasive ventilation; patients for whom pretransfer ventilator data could not be reliably obtained; and those with incomplete records where the need for intubation or the duration of invasive mechanical ventilation could not be determined were excluded.

NIV was defined in our study as providing ventilatory assistance utilizing CPAP or BiPAP modes through an external interface without the use of an endotracheal or tracheostomy tube. IMV was described as positive pressure ventilation administered by an ICU ventilator through a tracheostomy or endotracheal tube. The term "acute respiratory failure" (ARF) refers to a situation that requires advanced ventilatory support and is defined by either hypoxemia, hypercapnia, or both. The need for endotracheal intubation following a first NIV trial during the same ICU stay was referred to as NIV failure. This study's primary goal was to determine whether a standardized NIV regimen may lower the incidence of invasive mechanical ventilation in adult ICU patients with acute respiratory failure.

Following the hospital's ethical committee's clearance, ICU admission logs and electronic health record (EHR) queries of 27 adult patients admitted with acute respiratory failure in the study period who received NIV were assessed. For study purposes, admission notes, ventilator charts, and nursing/respiratory therapy documentation to determine whether NIV or IMV was initiated first within 24 hours were checked. Data was collected for age, gender, presence of comorbidities (e.g., COPD, heart failure, chronic kidney disease, diabetes), primary diagnosis leading to acute respiratory failure (e.g., COPD exacerbation, cardiogenic pulmonary edema, pneumonia, ARDS, sepsis), baseline physiologic and laboratory data around the time of ventilatory support initiation (Vital signs, arterial blood gases, and basic labs), ventilatory details such as NIV mode and interface settings at start and after 1–2 hours, and the timing of any switch from NIV to IMV were noted down.

Data was analyzed and assessed using Statistical Package for Social Sciences (SPSS) version 27.0. Normality of data was assessed by the Shapiro-Wilk test and normally distributed numerical variables were presented as mean and standard deviation and non-normally distributed data was presented as median and interquartile range, whereas categorical variables were presented as frequency and percentages.

This study evaluated the clinical outcomes of 27 ICU patients initially managed with NIV support. Seventeen patients (63.0%) subsequently required intubation, whereas 10 (37.0%) avoided invasive mechanical ventilation. Clinically, this relatively high rate of escalation suggests that patients receiving non-invasive respiratory support in this cohort represented a substantially ill population in whom close monitoring and repeated assessment were particularly important. However, the requirement for intubation should not automatically be interpreted as failure of care; rather, it may indicate progression of the underlying critical illness despite initial respiratory support.

HFNC was the most frequently used modality (51.9%), followed by BiPAP (29.6%) and CPAP (18.5%). Respiratory-support mode was not significantly associated with subsequent intubation (p = 0.668). This finding does not demonstrate equivalence between these modalities, because treatment selection was not randomized and the number of patients in each group was small. Clinically, the choice of HFNC, BiPAP, or CPAP is influenced by the underlying cause of respiratory failure, gas-exchange abnormalities, haemodynamic status, patient tolerance, and clinician assessment. Therefore, the absence of a statistical difference should not be used to favour one modality over another.

Early clinical response may provide useful information during bedside reassessment. Although the overall association between response at 1–2 hours and intubation was not statistically significant (p=0.626), worsening occurred in 41.2% of patients who were subsequently intubated compared with 20.0% of those who avoided intubation. Conversely, improvement occurred in 70.0% of non-intubated patients compared with 47.1% of intubated patients.

While these findings are exploratory, they support the clinical importance of reassessing patients soon after initiation of non-invasive support rather than relying solely on the initial treatment decision.

Among the physiological variables examined, MAP was the only factor significantly associated with intubation. Patients who required intubation had a lower mean MAP than those who avoided intubation (72.53 ± 13.89 versus 86.50 ± 17.06 mmHg; p = 0.029). Clinically, lower MAP may reflect greater hemodynamic compromise and overall severity of illness. This finding suggests that respiratory status should not be considered in isolation when evaluating the likelihood of successful non-invasive support. Hemodynamic stability may form an important component of the overall bedside assessment. Nevertheless, MAP cannot be considered an independent predictor from this study because the analysis was unadjusted and involved a small sample.

Other variables, including respiratory rate, GCS, oxygenation indices, lactate, ROX index, and HACOR score, were not significantly associated with intubation. These negative findings should be interpreted cautiously because the study may have been underpowered to detect clinically meaningful differences.

The most striking outcome was the association between intubation and mortality. Mortality occurred in 82.4% of intubated patients compared with 20.0% of non-intubated patients (p = 0.003). Importantly, this does not imply that intubation caused the higher mortality. Patients requiring invasive ventilation were likely to have experienced greater disease severity or physiological deterioration, making intubation a potential marker of a more severe clinical course.

Overall, these findings emphasize the importance of careful patient selection, haemodynamic assessment, and frequent reassessment during non-invasive respiratory support. The high rate of escalation to invasive ventilation highlights the need to identify deterioration promptly while avoiding unnecessary delay in clinically indicated intubation. Given the small sample size, single-cohort design, and absence of multivariable adjustment, these findings should be considered exploratory and confirmed in larger prospective studies.

In this study, 37% of ICU patients initially managed with non-invasive respiratory support avoided intubation, while 63% subsequently required invasive mechanical ventilation. Lower mean arterial pressure was significantly associated with the requirement for intubation highlighting the potential importance of hemodynamic stability when assessing patients receiving noninvasive respiratory support. Mortality was significantly higher among patients who required intubation; however, this likely reflects greater severity of illness rather than an effect of intubation itself. Overall, the findings emphasize careful patient selection, close monitoring, early recognition of deterioration, and timely escalation to invasive ventilation when clinically indicated. Given the small sample size and observational design, larger prospective studies are needed to confirm these findings.

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