| OBJECTIVE-To evaluate the clinical efficacy and safety of non-invasive helmet delivered continuous positive airway pressure (Helmet CPAP) in treating extubated patients with hypoxemia post cardiac surgery.METHODS-From March 2014 to July 2015,120 adult participants, admitted by the Center for Cardiac Intensive Care (CCIC) in Beijing Anzhen Hospital and suffering from hypoxemia 48 hours within the time of extubation after cardiac surgery, were enrolled in this study. Postoperative hypoxemia is defined by a postoperative radial artery blood oxygenation index (PaO2/FiO2) of 200mmHg or lower, after treating the patient with Venturi mask through which FiO2 is set at 50% and an indication that the oxygen saturation level is fully stabilized. The participants are randomly assigned to either the Helmet CPAP group (experimental group, n=60) or the high concentration mask group (control group, n=60). Patients received their respective treatments for at least 6 hours. Various clinical data for each participant is gathered prior to the study. Statistics such as blood gas measurements, vital signs, and echocardiography results were collected prior to the treatment,3 hours, and 6 hours after the treatment. The study also took note of the duration of Intensive Care Unit (ICU) stay, total hospital length of stay, mechanical ventilation rate, and mortality within 30 days. Incidence of complications and intolerance were also observed.RESULTS-A total of 120 participants were enrolled in the study. No significant differences were observed (p>0.05) between the experimental group and the control group in basic data before treatment (e.g. sex, age, body surface area, NYHA class, and co-morbidity), operation statistics (e.g. operation length, blood use in operation, and the use of cardiopulmonary bypass), and other clinical data before treatment (e.g. blood pressure, heart rate, arterial pO2, amount of vasoactive agents, and ventilator use).Participants receiving non-invasive helmet CPAP had an increase in oxygenation index (144.35±24.43 vs.201.35±52.97,p<0.05) and an increase in left ventricular ejection fraction (53.83±8.44 vs.55.40±8.44,p<0.05) after the treatment; they also reported a decrease in breathing rate (22.60±5.08 vs.18.53±4.13,p<0.05) and a decrease in shock index (0.85±0.35 vs.0.75±0.15,p<0.05) after the treatment. The amount of variation corresponded positively with the duration of treatment. The change witnessed in the experimental group were significantly larger than the change observed for the control group (p<0.05). The experimental group also reported a significantly lower use of mechanical ventilation and shorter ICU stay (6.67% vs.28.33% and 41.0 (25.0,67.5) vs.49.5 (32.5,90.8), respectively,p<0.05). Length of hospital stay after extubation, mortality rate within 30 days, and rate of pulmonary infection are lower in the experimental group, but these differences were not statistically significant.Non-invasive helmet CPAP is relatively safe and well-tolerated by the patients, shown by the high rate of completion of treatment and the absence of complaints for most participants in this study. Premature termination is low (8.3%); severe complications (e.g. severe abdominal distension, perforation of tympanic membrane, and respiratory acidosis) have a low incidence (1.7%); other malignant events (e.g. uncontrollable hypoxia, malignant arrhythmia, and abnormal mental symptoms) are also uncommon (8.3%). All of the above indicators do not differ significantly from the control group (p>0.05). Finally, no incidences of direct and indirect mortality or disability as a result of the non-invasive helmet CPAP treatment were observed in this study.DISCUSSION-Non-invasive helmet CPAP can be effectively and safely used in extubated patients with hypoxemia post cardiac surgery. It can improve patient’s oxygenation condition, heart and circulatory functions, reduce ICU stay and use of mechanical ventilation. However, it did not significantly reduce total length of hospital stay or mortality. |
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