DISCUSSION
Non-invasive ventilation has profoundly changed the approach to patients with ARF over the last 20 years, reducing hospital stay and avoiding the complications of IMV ¹⁴. The overall effectiveness of NIV use in avoiding intubation was reported to range between 69% and 79% in randomized studies ¹⁵. It was also reported that NIV had the potential to reduce the length of hospitalization and associated costs for adults with chronic obstructive pulmonary diseases and ARF ¹⁶.
For drowning patients with Szpilman scores of grades 3 and 4, administering high-flow oxygen therapy and/or mechanical ventilation was proposed ¹⁷. Despite the absence of recommendations for NIV use for cases of drowning-related ARF, NIV was previously applied with safety and efficacy for drowning patients ¹º. Similar to IMV, NIV provides airway pressure to prevent atelectasis and support respiratory muscle use while preventing hypoxemia. Its value might be based on the use of positive end-expiratory pressure (PEEP) over oxygen supplementation in the clinical course ¹º.
We could find very limited relevant data in the literature; to our knowledge, there is only one study evaluating adults and a few case reports of adults and children describing the use of NIV for drowning patients ¹º´¹¹´¹⁸ˉ²º. Our study has the largest number of pediatric cases to evaluate the efficacy of NIV treatment to date.
Michelet et al. evaluated adults with drowning-related ARF in intensive care units and assessed the efficacy of ventilator strategies used. They declared that their cases were grades 3 to 5 according to the Szpilman classification, and of the 25 patients who underwent NIV treatment, 4 were intubated due to respiratory or neurological deterioration. They reported similar neurological outcomes and correction of hypoxemia and acidosis comparing patients treated with NIV versus IMV after drowning. Furthermore, patients who were treated with NIV had a lower incidence of infection and decreased length of intensive care unit and hospital stay ¹º.
In our study, all children were treated using BiPAP, and none of them deteriorated to require IMV. The Szpilman classification was grade 3 or 4 for our cases. Our results demonstrate that NIV treatment was associated with rapid improvement in the early phase of oxygenation. Considering drowning-related ARF, which is characterized by profound but reversible hypoxemia without relevant hypercapnia, early application of NIV may aid in the hastening of clinical improvement.
Our decision to use NIV was made on the basis of confidence that its early application could be a preventive treatment strategy, with the reversible nature of drowning, for eligible patients without complete loss of consciousness to reduce morbidity ¹º´²º. We preferred to use BiPAP to reduce the respiratory workload for patients who were tachypneic, whereas the application of PEEP was repeatedly suggested and CPAP was used as frequently as BiPAP in pre-hospital settings ¹º. However, the use of NIV for drowning patients with altered mental status should be considered with a high index of caution because there may be increased risk of vomiting and aspiration ⁹. The initial neurological assessment appears to be of paramount importance to initially choose the ventilator strategy. The occurrence of neurological deterioration is an indication for IMV rather than NIV use. Gregorakos et al. evaluated adults with drowning-related ARF in the emergency department and concluded that IMV could be avoided in non-comatose patients ¹⁸. The improvement of neurological status as well as the lower incidence of hemodynamic instability could facilitate alternative treatment choices such as NIV ¹⁴´¹⁵. At this point, the Szpilman score, which is first based on neurological status and secondly on respiratory and hemodynamic status, could guide the physician for the choice of ventilation strategy.
Ruggeri et al. reported successful NIV use for a 45-year-old man who had ARF secondary to drowning after an epileptic crisis ¹¹. Dottorini et al. reported 13- and 19-year-old drowning patients without loss of consciousness who presented with radiographic appearance of pulmonary edema and were successfully treated with nasal CPAP therapy, highlighting the importance of neurological status in the choice of ventilation strategy ¹⁹. Çağlar et al. also reported 5-, 12-, and 13-year-old drowning patients with pulmonary edema who were successfully treated with BiPAP therapy in the pediatric emergency department. The Szpilman classification was grade 3 or 4 for these patients ²º.
We acknowledge the limitations related to the retrospective nature of our study. Information was missing for some patients. Also, we only evaluated the patients who underwent NIV treatment. If we had a control group, we could have compared the hastening of clinical improvement, morbidity, complications, and length of stay in the hospital for NIV treatment.
We have reported a favorable clinical course of drowning patients who underwent early use of NIV in a pediatric emergency department. Management of drowning patients by NIV with close follow-up can be successfully applied in selected cases. The choice of NIV appears to be a valuable preventive ventilation strategy for reducing IMV and implicitly reducing morbidity resulting from the complications of IMV. Nevertheless, multicenter studies with larger case series are required to determine the effectiveness of choices for ventilator strategy and to reveal the benefits of early application of NIV for drowning patients in pediatric emergency settings, and to help shape treatment guidelines.