Bilevel Positive Airway Pressure Group Research Articles

Comparative Effect of High-Frequency Nasal Cannula and Noninvasive Ventilation on the Work of Breathing and Postoperative Pulmonary Complication after Pediatric Congenital Cardiac Surgery: A Prospective Randomized Controlled Trial.

Various forms of commonly used noninvasive respiratory support strategies have considerable effect on diaphragmatic contractile function which can be evaluated using sonographic diaphragm activity parameters. To compare the magnitude of respiratory workload decreased as assessed by thickening fraction of the diaphragm and longitudinal diaphragmatic strain while using high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) modes [nasal intermittent positive pressure ventilation (NIPPV) and bilevel positive airway pressure (BiPAP)] in pediatric patients after cardiothoracic surgery. This prospective randomized controlled trial was performed at a tertiary care surgical intensive care unit in postcardiac surgery patients aged between 1 and 48 months, who were randomly allocated into three groups: 1) HFNC (with flows at 2 L/kg/min), 2) NIPPV via RAMS cannula in PSV mode (pressure support 8 cmH2O, PEEP 5 cmH2O), and 3) BiPAP in nCPAP mode (CPAP of 5 cmH2O). Measurements were recorded at baseline after extubation (R0) and subsequently every 12 hourly (R1, R2, R3, R4, R5) at 12, 24, 36, 48, and 60 hours respectively until therapy was discontinued. Sixty patients were included, with 20 patients each in the NIPPV group, HFNC group, and BiPAP group. Longitudinal strain at crura of diaphragm was lower in the BiPAP group as compared to HFNC group at R2-R4 [R2 (-4.27± -2.73 vs - 8.40± -6.40, P = 0.031), R3 (-5.32± -2.28 vs -8.44± -5.6, P = 0.015), and R4 (-3.8± -3.42 vs -12.4± -7.12, P = 0.040)]. PFR was higher in HFNC than NIPPV group at baseline and R1-R3[R0 (323 ± 114 vs 264 ± 80, P = 0.008), R1 (311 ± 114 vs 233 ± 66, P = 0.022), R2 (328 ± 116 vs 237 ± 4, P = 0.002), R3 (346 ± 112 vs 238 ± 54, P = 0.001)]. DTF and clinical parameters of increased work of breathing remain comparable between three groups. The rate of reintubation (within 48 hours of extubation or at ICU discharge) was 0.06% (1 in NIPPV, 1 in BiPAP, 2 in HFNC) and remain comparable between groups (P = 1.0). BiPAP may provide better decrease in work of breathing compared to HFNC as reflected by lower crural diaphragmatic strain pattern. HFNC may provide better oxygenation compared to NIPPV group, as reflected by higher PFR ratio. Failure rate and safety profile are similar among different methods used.

Bilevel positive airway pressure ventilation in patients susceptible to hypoxemia during procedural sedation for colonoscopy: a prospective randomized controlled study

Background and aimsHypoxemia is one of the most common adverse events during colonoscopy, particularly among patients who are diagnosed with obstructive sleep apnea (OSA) or are overweight. Consequently, the objective of this study is to evaluate the effectiveness of bilevel positive airway pressure (BPAP) ventilation for patients with high risk hypoxemia during colonoscopy with sedation. MethodsIn this trial, 127 patients who met the eligibility criteria were randomly assigned to the BPAP oxygen and nasal cannula (NC) group. The primary endpoint was the incidence of hypoxemia. ResultsCompared to the use of NC, BPAP ventilation exhibited a significant reduction in the incidence of hypoxemia, decreasing it from 23.8% to 6.3% (absolute risk difference [ARD]: 17.5% [95% confidence interval (CI), 5.4 to 29.6], p = 0.006). Importantly, BPAP ventilation prevented the occurrence of severe hypoxemia (9.5% vs. 0%, ARD: 9.5% [95% CI, 2.3 to 16.7], p = 0.035). Besides, the BPAP group required fewer airway interventions (p < 0.05). ConclusionsIn individuals with OSA or overweight status, the use of BPAP ventilation during colonoscopy significantly reduced the incidence of hypoxemia.

The Effect of Bilevel Positive Airway Pressure on Voice Quality

Inflammation of the upper airways, thickening of the lateral pharyngeal walls, elongation of the soft palate and uvula, hypertrophy of the tonsils and base of the tongue can be seen in obstructive sleep apnea syndrome patients. Changes in these structures may affect articulation and phonation, negatively affecting the quality of the voice. Positive airway pressure (PAP) treatment reduces the volume of the root of the tongue, dissolves the edema in the upper respiratory tract, increases the posterior pharyngeal area, and positively changes the quality of the voice. A total of 151 people, 50 control group, and 101 patients, were included in the study between December 2020 and December 2021. The patient group was divided into two groups as continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BPAP) users. All voice recordings were made in the control group and the patient group before and 3 months after CPAP and BPAP treatment, and were evaluated with the Praat (Paul, 2001) voice analysis program. The fundamental frequency of the sound (F0), frequency perturbation (jitter), amplitude perturbation (shimmer), noise-to-harmonic ratio (NHR) values were evaluated in the patient and control groups, and they were compared with each other before and after the treatment in the CPAP and BPAP groups. Before and after PAP treatment; the changes in F0, Jitter, Shimmer, and NHR in the CPAP and BPAP group were statistically significant (P < 0.05). While the F0 change before and after PAP treatment was the most in the CPAP group, the jitter, shimmer and NHR changes were the most in the BPAP group. Regular 3-month PAP treatment positively affects F0, jitter, shimmer and NHR values. The greatest F0 change is in the use of CPAP, the improvement in jitter, shimmer and NHR is the most in the use of BPAP.

Bi-level Positive Airway Pressure Versus Nasal CPAP for the Prevention of Extubation Failure in Infants After Cardiac Surgery.

Extubation early in the postoperative period is beneficial to the recovery and rehabilitation of patients. This study compared the postoperative extubation failure rates among infants who received postextubation respiratory support by either bi-level positive airway pressure (BPAP) or nasal CPAP following cardiac surgery. This was a single-center randomized controlled trial registered at the Chinese Clinical Trial Registry (number ChiCTR2000041453) and was conducted between January 2020 and March 2021. Ventilated infants who underwent cardiac surgery were randomized to either a BPAP or a nasal CPAP group for ventilatory support following extubation. The primary outcome measure was the extubation failure rate within 48 h. The analyses included 186 subjects. Treatment failure necessitating re-intubation was noted in 14 of the 93 infants (15%) in the BPAP group and in 11 of the 93 infants (12%) in the nasal CPAP group (P = .52). Moreover, there were no statistically significant differences between the 2 groups regarding the duration of noninvasive ventilation (P = .54), total enteral feeding time (P = .59), or complications (P = .85). We found that both the BPAP group and the nasal CPAP group showed significantly improved oxygenation and relief of respiratory distress after treatment. However, the PaCO2 level within 24 h was significantly lower in the BPAP group (P = .001) than in the CPAP group. Additionally, the PaO2 /FIO2 in the BPAP group was significantly higher than in the nasal CPAP group at 6 h, 12 h, and 24 h after treatment (P < .001). The introduction of BPAP for postextubation respiratory support was not inferior to nasal CPAP in infants after cardiac surgery. Moreover, BPAP was shown to be superior to nasal CPAP in improving oxygenation and carbon dioxide clearance.

Pressão positiva de duplo nível em via aérea melhora o balanço autonômico no pós-operatório de cirurgia cardíaca: ensaio randomizado

ABSTRACT The use of bilevel positive airway pressure (BiPAP) has repercussions on cardiorespiratory outcomes. However, the literature still lacks analyses of the postoperative influence of BiPAP on the modulation of the autonomic nervous system after cardiac surgery. This study aimed to evaluate the effects of BiPAP on peripheral oxygen saturation, vital signs, and autonomic balance during hospitalization after cardiac surgery. This randomized controlled trial evaluated 36 patients before and after surgery. The BiPAP group was treated in two 20-minute daily sessions of routine physical therapy since 18 hours after surgery until discharge. The control group received routine physical therapy during the same period. Our primary outcome was peripheral oxygen saturation. Secondary outcomes were vital signs and autonomic balance evaluated by heart rate variability. We observed that peripheral oxygen saturation and blood pressure were unaffected at hospital discharge. Both groups showed a similar increase in heart and respiratory rates. The BiPAP group showed a reduction of the low sympathetic frequency component in −27.1 n.u. (95% CI: −39 to −15.2), increase of high parasympathetic frequency in 27.1 n.u. (95% CI: 15.2 to 39), and an improvement to the LF/HF ratio in −2.5 (95% CI: −3.8 to −1.2), when compared to the control group. BiPAP attenuated sympathetic activity and improved vagal modulation and autonomic balance at hospital discharge. These findings evidence that BiPAP enables more efficient autonomic mechanisms during hospitalization after cardiac surgery.

P0437 / #2122: OUTCOMES OF NON-INVASIVE BI-LEVEL POSITIVE AIRWAY PRESSURE VENTILATION AS INITIAL MANAGEMENT OF ACUTE RESPIRATORY FAILURE IN PEDIATRIC CRITICAL CARE

Aims & Objectives: To assess the outcomes of non-invasive bi-level positive airway pressure (BLPAP) ventilation as first-line therapy in children with acute respiratory failure (ARF). Methods: Design: A retrospective observational study. Setting: Pediatric Intensive Care Unit (PICU) of a university hospital. Patients: Eighty-seven patients subjected to non-invasive ventilation (NIV) as the initial management in a total of 92 ARF episodes were included, from July-2017 to June-2020. Each episode was treated as an independent event. Main Outcome Measures: We evaluated changes of heart rate, respiratory rate and SpO2/FiO2 ratio (S/F) at 3, 6, 12, and 24 hours after NIV onset, and compared patients using BLAP vs CPAP as first-line therapy. Results: BLPAP was started in 63 episodes (68.5%). Ten of 29 episodes (34.5%) that started CPAP were escalated to BLPAP. Baseline characteristics, initial physiologic parameters and severity score did not differ between groups. The S/F ratio increase at 6 hours was significantly greater in the BLPAP group (mean 48; CI95% 29-66) compared to the CPAP group (mean 21; CI95% -17-59; p=0,011). The trend continued over time, S/F ratio increase was greater in the BLPAP group at 24 hours. No difference was found in the intubation rate (BLPAP 4.4% vs CPAP 3.2%). The mean length of stay in the PICU was 1 day longer in the CPAP group, although it was not a significant difference. Conclusions: In children with ARF, the initial use of BLPAP rapidly improves the S/F ratio compared to CPAP. BLPAP as first-line therapy could be the best option for the management of patients with ARF.

Determinants of bilevel therapy in the management of obstructive sleep apnea

The aim of this study was to investigate potential patient or polysomnogram (PSG) characteristics that can help determine who might benefit from bilevel positive airway pressure (BPAP) in the treatment of uncomplicated OSA. This was a single center, retrospective, observational study in which 19 patients who met our inclusion criteria for BPAP were matched to 40 patients in the control group. Data on patient baseline characteristics as well as PSG results were analyzed. Baseline patient and PSG characteristics were similar with the exception of shorter sleep time in the BPAP group, 290min compared with 351min (p = 0.005). Analysis of oxygen saturations revealed that the percent of total sleep time (TST) spent below90% (SpO2 < 90%) was statistically higher in BPAP group (mean 21.4% ± 23.6%) compared with CPAP (mean 9.1% ± 11.1%, p= 0.045). For every 5% increase in TST at SpO2 < 90%, there is a 28% increase in the odds of BPAP prescription (OR = 1.276, 95%CI 1.029, 1.582, p= 0.027), and for every 10% increase, there is an increase of 63% (OR 1.627, 95%CI 1.058-2.502). The Hosmer-Lemeshow goodness-of-fit test revealed a good fit (p= 0.23). The AUC was 0.7. There is an association between duration of hypoxemia on the PSG and the likelihood of requiring BPAP for the treatment of uncomplicated OSA. More research is needed to understand the best patient-centered therapy when initiating PAP in the management of OSA.

Use of bilevel positive pressure ventilation in patients with bronchiolitis.

This study aims at describing the use of bilevel positive airway pressure (BiPAP) in infants with severe bronchiolitis. The use of BiPAP in infants with bronchiolitis may be associated with a worst outcome. A single-center retrospective study performed from October 2013 to April 2016. All infants from 1 day to 6 months of age admitted in the pediatric intensive care unit (PICU) were included if they had a clinical diagnosis of bronchiolitis and if they required any type of noninvasive ventilation (NIV), including high flow nasal cannula, continuous positive airway pressure and BiPAP at admission in PICU. There was no local written protocol regarding the ventilator management during the study. Overall, 252 infants (median age 45 (26-72) days) were included in the study and 110 infants (44%) were supported by BiPAP at admission. More infants were born preterm in the group of patients supported by BiPAP at admission. No complication related to NIV occurred. Patients in the BiPAP group had a longer duration of noninvasive support as well as a longer PICU length of stay. However, hospital length of stay did not differ according to the type of respiratory support at admission. The use of BiPAP was not associated with endotracheal intubation, however it was associated with increased PICU length of stay and increased duration of NIV.

Comparison of three different noninvasive ventilation strategies as initial respiratory support in very low birth weight infants with respiratory distress syndrome: A retrospective study

BackgroundThere is inadequate evidence regarding which noninvasive ventilation (NIV) is superior for initial respiratory support of preterm infants with respiratory distress syndrome. ObjectivesTo compare the failure of noninvasive ventilation (NIV) and neonatal outcomes between nasal continuous positive airway pressure (NCPAP), bi-level positive airway pressure (BiPAP), and nasal intermittent positive pressure ventilation (NIPPV) as the initial respiratory support with less invasive surfactant administration (LISA) in very low birth weight (VLBW) infants. MethodsMedical records of 419 VLBW infants born at 26–30weeks’ gestation who did not require intubation in the delivery room and were initially supported with either NCPAP (n=221), BiPAP (n=101), or NIPPV (n=97) were retrospectively reviewed. The LISA approach was preferred in cases of surfactant requirement. The primary outcome was the failure of NIV within the first 72h of life. Failure of NIV was defined as the persistence or recurrence of one or more of the following: hypoxemia, respiratory acidosis, more than one episode of apnea requiring bag and mask ventilation or more than six episodes of apnea requiring stimulation over a 6-h period. Data were analyzed using univariate and multivariate logistic regression analysis. ResultsFailure of NIV within the first 72h of life was significantly higher in the NCPAP group (29.4%) compared with the BiPAP (12.9%) or NIPPV (12.4%) group (P<0.001). However, the BiPAP and NIPPV groups were not different in terms of NIV failure (P=0.91). Multivariable logistic regression analysis showed that antenatal steroid administration (OR: 0.49, 95% CI: 0.27–0.90; P=0.02) and gestational age˂28weeks (OR: 2.03, 95% CI: 1.18–3.49; P=0.01) were independent factors that influence failure of NIV within the first 72h of life. ConclusionCompared with NCPAP, the use of NIPPV/BiPAP strategies for initial respiratory support can reduce the need for invasive ventilation in infants born at 26–30weeks’ gestation.

Effectiveness of nCPAP for moderate preterm infants compared to BiPAP: A Randomized, Controlled Non-Inferiority Trial.

Bilevel positive airway pressure (BiPAP) has recently been used in preterm infants with respiratory distress as an alternative to nasal continuous positive airway pressure (nCPAP) because, theoretically, BiPAP is thought to be more effective than nCPAP. However, the results of some studies comparing nCPAP with BiPAP as the initial respiratory support were controversial. The aim of this study is to compare the clinical effectiveness and safety of nCPAP with BiPAP at gestational ages of 30+0 to 34+6 weeks. A total of 93 infants with gestational ages of 30+0 to 34+6 weeks, who presented with respiratory distress within 24h after birth, were randomized to the nCPAP group or the BiPAP group. The primary outcome was the incidence of treatment failure with these two non-invasive respiratory support devices. Criteria for treatment failure included any of the following: respiratory acidosis (PaCO2 >65mmHg with pH <7.2), hypoxia (FiO2 >0.4), or apnea (>2-3 episodes of apnea/h). There was no statistically significant difference in treatment failure between the two groups (P = 0.576). The risk difference comparing treatment failure rate between nCPAP and BiPAP groups was -4.7% (95% CI: -21.5-11.9). Nasal continuous positive airway pressure is not inferior to BiPAP as an initial management of respiratory distress in these premature infants. We therefore conclude that nCPAP can be used as an initial management for preterm infants at gestational age of between 30 and 35weeks as a substitute for BiPAP.

Bilevel Positive Airway Pressure ventilation efficiently improves respiratory distress in initial hours treating children with severe asthma exacerbation

Treatment of severe asthma exacerbation could be challenging, especially in the initial hours of acute attack when systemic corticosteroid is yet to take effect. In spite of using inhaled agents, the role of non-invasive ventilation (NIV), including Bilevel Positive Airway Pressure (BiPAP), had been addressed recently. We reviewed 5-year experience in our hospital for records of patients who were admitted to pediatric intensive care unit because of severe asthma attack. The included admission records from 2012 to 2017 were grouped according to BiPAP use (Yes/No). Clinical parameters (heart rate (HR), respiratory rate (RR), SpO2 and serum pCO2) at selected time intervals of treatment were collected for both groups and analyzed. We included data of 46 admissions from 33 different patients (24 with BiPAP and 21 without BiPAP.) The BiPAP group had significantly higher initial RR as well as higher severity scores compared with the other group (p < 0.001). The RR improved significantly in the following time intervals in BiPAP group. There was no significant difference in HR between groups in any of the time intervals. The serum pCO2 levels decreased significantly after initiation of ventilation support in the BiPAP group, and SpO2 levels improved significantly for both groups. BiPAP seemed efficient in improving respiratory rate and oxygenation in our study. It does not seem to cause additional irritation regarding that HR was not increased in BiPAP group compared with non-BiPAP group. Overall, BiPAP ventilation is safe and efficient in treating children with severe asthma attack.

Preventing Respiratory Failure After Cardiac Surgery Using Post-extubation Bilevel Positive Airway Pressure Therapy

Objective: Our study aimed to evaluate if an extubation protocol for all post-operative cardiac patients in the cardiothoracic intensive care unit using intermittent bilevel positive airway pressure (BiPAP) could reduce the rate of re-intubation.Methods: A total of 1,718 patients undergoing cardiac surgery from May 2012 to April 2016 were analyzed. Patients from May 2014 to April 2016 were included in a post-extubation BiPAP therapy protocol that included one hour of BiPAP followed by three hours of a nasal cannula for 24 hours after extubation in the cardiothoracic intensive care unit. The protocol cohort was retrospectively compared to a control group (nasal cannula only) from May 2012 to April 2014. All demographic and outcome data were analyzed from our institution’s Society of Thoracic Surgeons (STS) Cardiac Database.Results: There was no statistical difference in the rate of re-intubation between the BiPAP group (n = 35; 4.07%) and the control group (n = 34; 3.96%; p = 0.9022). Sub-group analysis of the 69 re-intubated patients identified several significant risk factors: prior valve surgery (p = 0.028), chronic lung disease (p = 0.0343), emergent operation (p = 0.0016), longer operating room time (p = 0.0109), cardiopulmonary bypass time (p = 0.0086), higher STS predicted risk of mortality score (p = 0.0015). Re-intubation was associated with higher 30-day mortality rates (p = 0.0026), prolonged cardiothoracic intensive care unit length of stay (p < 0.0001), and hospital length of stay (p < 0.0001).Conclusion: While a BiPAP protocol did not show a significant difference in re-intubation rates after cardiac surgery, the subgroup analysis of re-intubated patients showed several significant risk factors for re-intubation. Early identification of these risk factors when considering extubation may help teams avoid associated morbidity and mortality outcomes.

Randomized Trial of Bilevel versus Continuous Positive Airway Pressure for Acute Pulmonary Edema

BackgroundStudies have shown different clinical outcomes of noninvasive positive pressure ventilation (NPPV) from those of continuous positive airway pressure (CPAP). ObjectiveWe evaluated whether bilevel positive airway pressure (BPAP) more rapidly improves dyspnea, ventilation, and acidemia without increasing the myocardial infarction (MI) rate compared to continuous positive pressure ventilation (CPAP) in patients with acute cardiogenic pulmonary edema (APE). MethodsPatients with APE were randomized to either BPAP or CPAP. Vital signs and dyspnea scores were recorded at baseline, 30 min, 1 h, and 3 h. Blood gases were obtained at baseline, 30 min, and 1 h. Patients were monitored for MI, endotracheal intubation (ETI), lengths of stay (LOS), and hospital mortality. ResultsFourteen patients received CPAP and 13 received BPAP. The two groups were similar at baseline (ejection fraction, dyspnea, vital signs, acidemia/oxygenation) and received similar medical treatment. At 30 min, PaO2:FIO2 was improved in the BPAP group compared to baseline (283 vs. 132, p < 0.05) and the CPAP group (283 vs. 189, p < 0.05). Thirty-minute dyspnea scores were lower in the BPAP group compared to the CPAP group (p = 0.05). Fewer BPAP patients required intensive care unit (ICU) admission (38% vs. 92%, p < 0.05). There were no differences between groups in MI or ETI rate, LOS, or mortality. ConclusionsCompared to CPAP to treat APE, BPAP more rapidly improves oxygenation and dyspnea scores, and reduces the need for ICU admission. Further, BPAP does not increase MI rate compared to CPAP.

Effect of adding postoperative noninvasive ventilation to usual care to prevent pulmonary complications in patients undergoing coronary artery bypass grafting: A randomized controlled trial

We compared the efficacy of noninvasive ventilation with bilevel positive airway pressure added to usual care versus usual care alone in patients undergoing coronary artery bypass grafting. We performed a 2-group, parallel, randomized controlled trial. The primary outcome was time until fitfor discharge. Secondary outcomes were partial pressure of carbon dioxide, forced expiratory volume in 1second, atelectasis, adverse events, duration of intensive care stay, and actual postoperative stay. A total of 129 patients were randomly allocated to bilevel positive airway pressure (66) or usual care (63). Three patients allocated to bilevel positive airway pressure withdrew. The median duration of bilevel positive airway pressure was 16hours (interquartile range, 11-19). The median duration of hospital stay until fit for discharge was 5days for the bilevel positive airway pressure group (interquartile range, 4-6) and6days for the usual care group (interquartile range, 5-7; hazard ratio, 1.68; 95% confidence interval, 1.08-2.31; P=.019). There was no significant difference in duration of intensive care, actual postoperative stay, and mean percentage of predicted forced expiratory volume in 1second on day 3. Mean partial pressure of carbon dioxide was significantly reduced 1hour after bilevel positive airway pressure application, but there was no overall difference between the groups up to 24hours. Basal atelectasis occurred in 15 patients (24%) in the usual care group and 2 patients (3%) in the bilevel positive airway pressure group. Overall, 30% of patients in the bilevel positive airway pressure group experienced an adverse event compared with 59% in the usual caregroup. Among patients undergoing elective coronary artery bypass grafting, the use of bilevel positive airway pressure at extubation reduced the recovery time. Supported by trained staff, more than 75% of all patients allocated to bilevel positive airway pressure tolerated it for more than 10hours.

Perioperative ventilatory strategies for improving arterial oxygenation and respiratory mechanics in morbidly obese patients undergoing laparoscopic bariatric surgery

BackgroundOxygenation impaired in morbidly obese patients undergoing bariatric surgery. We studied the safety and efficacy of recruitment maneuvers with different levels of positive end expiratory pressure (PEEP) in intraoperative and postoperative periods. The influence of postextubation bilevel positive airway pressure (BiPAP) on oxygenation was also studied.MethodsThe study included 60 patients with body mass index (BMI) > 50 kg m2 undergoing laparoscopic bariatric surgery. Patients were randomized into three groups; All study groups received 40 cm H2O inspiratory pressure followed by PEEP 10 cm H2O and O2 postoperatively in the first group (PEEP 10 + O2 Group), PEEP 15 cm H2O and O2 postoperatively in the second one (PEEP 15 + O2 Group), and PEEP 15 and postoperative BiPAP in the third one (PEEP 15 + BiPAP Group). Primary end points were intraoperative oxygenation, ventilation, respiratory mechanics, hemodynamics, and postoperative oxygenation. Secondary end points were Vasopressor doses, length of intensive care unit (ICU) stay, and postoperative pulmonary complications.ResultsHemodynamics, and total vasopressor doses were comparable between groups. PaO2/FiO2 decreased after induction of anesthesia and pneumoperitonium and was similar between groups. After recruitment, PaO2/FiO2 increased significantly in PEEP 15 groups (P < 0.05). Static compliance decreased in all study groups 5 min after induction of pneumoperitonium, however, improved significantly after recruitment in the PEEP 15 groups (P < 0.05). PaO2/FiO2 was significantly higher in PEEP 15 groups 1 h postoperatively (P < 0.05). However, it was significantly increased only in PEEP 15 + BIPAP at 2, 12, 24 h postoperatively. ICU stay was significantly shorter in the PEEP + BiPAP group (P < 0.05). Complications were comparable between groups.ConclusionsRecruitment maneuver followed by PEEP 15 cm H2O improved oxygenation and respiratory mechanics during intraoperative and early postoperative periods in morbidly obese patients undergoing laparoscopic bariatric surgery. Moreover, postoperative BiPAP was essential to maintain oxygenation in these patients.

Role of bilevel positive airway pressure in the management of preterm newborns who have received surfactant

Surfactant given during brief intubation followed by immediate extubation on nasal continuous positive airway pressure [Intubation-Surfactant-Extubation (InSurE) approach] is used to treat respiratory distress syndrome in newborns. Our aim was to evaluate whether bilevel positive airway pressure (BiPAP) after InSurE failure is able to prevent the need for mechanical ventilation (MV). Chart data of infants with a birth weight <1500 gr or GA <32weeks undergoing InSurE in the period 2002-2008 in an Italian Tertiary Neonatal Intensive Care Unit were reviewed retrospectively. InSurE failure was defined as follows: FiO(2) >0.4, respiratory acidosis or intractable apnoea within 1 week. After InSurE failure, newborns born before the implementation of BiPAP (historical control group) received MV, whereas those born after BiPAP implementation (BiPAP group) received BiPAP and underwent MV only if failure criteria persisted. The two groups were compared to evaluate whether BiPAP reduced the need for MV in the 7 days after InSurE failure. Six of twenty-two (27%) and 14 of the 38 (37%) infants failed InSurE in the two groups, respectively (p > 0.05). Need for MV was 27% in the historical control group versus 0% in the BiPAP group (risk estimate, 3.38; 95% CI, 2.24, 5.09; p = 0.001). BiPAP reduced the need for MV after InSurE failure.

Effect of BiPAP noninvasive ventilation on patients with acute left ventricular failure

Objective To observe the effect of Bi-level positive airway pressure(BiPAP) noninvasive ventilation on acute left ventricular failure(LVF). Methods BiPAP group :32 patients with severe LVF from various causes were treated by BiPAP with traditional drugs. Control group:32 patients were treated with traditional drugs alone,and the results were compared with those of BiPAP group. Results Dyspnea was relieved in all patients in BiPAP group,both the respiratory rate and heart rate were slowed,the vital signs were stable,and PaO2 ,SaO2 went up. The total effective rate was 100%, which was only 68. 75% in control group. Conclusion The use of BiPAP noninvasive ventilation therapy is feasible and effective on LVF. Key words: Left heart failure; Veutilators

Cardiac Effects of Continuous and Bilevel Positive Airway Pressure for Patients With Heart Failure and Obstructive Sleep Apnea: A Pilot Study

Obstructive sleep apnea (OSA) is prevalent in patients with heart failure. Treatment with continuous positive airway pressure (CPAP) improves systolic function in patients with heart failure. Bilevel positive airway pressure (PAP) is another treatment modality for OSA. The intermediate-term effect of bilevel PAP on left ventricular ejection fraction (LVEF) in patients with stable heart failure and OSA has not been compared to the effect of CPAP. In this pilot randomized controlled trial, patients with stable systolic dysfunction and newly diagnosed OSA (n = 24) were randomized to receive either CPAP or bilevel PAP. Titration was done in the sleep laboratory using a CPAP-based algorithm. Primary outcome was the improvement in LVEF after 3 months of treatment. Other measurements included 6-min walk test, Epworth sleepiness scale score, and the Minnesota Living With Heart Failure questionnaire. Bilevel PAP increased LVEF 7.9% (LVEF percentage scale) more than CPAP (95% confidence interval [CI], 2.3 to 13.4; p = 0.01). In the bilevel PAP group, LVEF increased 8.5% (95% CI, 3.7 to 13.4; p = 0.002). In the CPAP group, LVEF did not change significantly (0.5%; 95% CI, - 2.7 to 3.7; p = 0.7). The difference in LVEF improvement between the two groups was still significant after adjustment for adherence, level of treatment positive pressure, body mass index, and severity of OSA. This pilot randomized controlled trial suggests that bilevel PAP is superior to CPAP in improving LVEF in patients with systolic dysfunction and OSA. Larger trials are required to evaluate the mechanism behind this effect.

The effect of bi-level positive airway pressure mechanical ventilation on gas exchange during general anaesthesia

Atelectasis may occur and ventilation-perfusion mismatch may increase during general anaesthesia with neuromuscular paralysis and mechanical ventilation, though preservation of some intermittent muscle contraction might mitigate this process. There is still no ideal manoeuvre to minimize such mismatch or atelectasis. Bi-level positive airway pressure (BiPAP) ventilation adjusts to extra breaths and improves gas exchange during recovery of diaphragm function after neuromuscular paralysis. We hypothesize that BiPAP ventilation may limit the development of pulmonary shunt and may improve ventilation-perfusion mismatch when compared with standard IPPV, with or without PEEP when neuromuscular paralysis has been used during surgery. Twenty ventilated patients either on BiPAP or IPPV with or without PEEP were studied randomly using the multiple inert gas elimination technique (MIGET) at 60 and 120 min after rocuronium at induction and after 60 min. Non-invasive cardiac output (NICO) monitoring and plasma concentrations of rocuronium were measured. We compared the data of MIGET, gas exchange, haemodynamic variables and pulmonary mechanics measurements between the different ventilatory modes. Intrapulmonary shunt (blood flow to V(A)/Q < 0.005) did not increase at 60 min of anaesthesia in any of the different ventilation modes compared with the shunt value before anaesthesia. Log standard deviation of perfusion increased in IPPV, with and without PEEP groups, compared with the baseline (P< 0.05) but did not increase in the BiPAP group. BiPAP ventilation generated a higher level of Pa(O2)than IPPV with or without PEEP (P<0.05). BiPAP ventilation was beneficial in decreasing ventilation-perfusion mismatch and improving oxygenation when compared with conventional IPPV (with or without PEEP).

Treatment of Acute Bronchospasm With β-Adrenergic Agonist Aerosols Delivered by a Nasal Bilevel Positive Airway Pressure Circuit

Study objective: To determine whether β-adrenergic agonist aerosols are more effective in treating acute bronchospasm if delivered by nasal bilevel positive airway pressure (BiPAP) than by a small-volume nebulizer (SVN). We hypothesized that BiPAP would reduce the work of breathing in asthmatic patients and thereby hasten improvement of bronchospasm from β-agonist therapy. Previous trials with aerosols given by intermittent positive-pressure breathing were unrewarding, but BiPAP is unique in that inspiratory (IPAP) and expiratory (EPAP) support pressures may be set separately. Design: Convenience-randomized prospective clinical study. Setting: Emergency department of an urban tertiary care teaching hospital. Participants: Afebrile, wheezing patients between 18 and 40 years of age. Interventions: Patients were randomly assigned to receive two doses of aerosolized albuterol (2.5 mg in 3 mL normal saline solution), 20 minutes apart, delivered by either SVN (n=40) or BiPAP (n=60) by nosemask or facemask (IPAP, 10 cm H 2O; EPAP, 5 cm H 2O). Results: Peak expiratory flow rate (PEFR), arterial blood oxygen saturation (by pulse oximetry), and pulse and respiratory rates were measured at baseline and after each treatment. The two treatment groups had similar values for pulse oximetry, pulse rate, respiratory rate, and percent of predicted peak expiratory flow rate (%PPEFR) at entry, and all patients experienced similar changes in the first three of these variables through the course of treatment. BiPAP patients had a significantly greater increase in %PPEFR after each treatment ( P =.0011) and from baseline to completion ( P =.0013). Increase in absolute PEFR was greater in the BiPAP group (from 211±89 [mean±SD] to 357±108 L/minute for BiPAP, from 183±60 to 280±87 L/minute for SVN; P =.0001). Conclusion: In this population, response to initial ED management of bronchospasm, as measured by PEFR, was better with aerosols delivered by BiPAP than with those delivered by SVN. [Pollack CV Jr, Fleisch KB, Dowsey K: Treatment of acute bronchospasm with β-adrenergic agonist aerosols delivered by a nasal bilevel positive airway pressure circuit. Ann Emerg Med November 1995;26:552-557.]