Bi-level positive airway pressure

BiPAP bi-level positive airway pressure SNRI serotonin norepinephrine reuptake inhibitor SSRI selective serotonin reuptake inhibitor... 

Bi-level Positive Airways Pressure air (if necessary enriched with oxygen 24% or 28%) is administered through a close fitting face-mask, at a positive pressure of 14-18 cm of water to support inspiration, then at a pressure of 4 cm of water during expiration to help maintain patency of small airways and increase gas exchange in alveoli. 

Schwartz AR, Kacmarek RM, Hess DR. Factors affecting oxygen delivery with bi-level positive airway pressure. Respir Care 2004 49(3) 270-275. 

She was started on bi-level positive airway pressure ventilation 20/8 cmH20 with a rate of 15 breaths per minute (bpm). Her nocturnal gas exchange (Fig. 4) returned to within... 

Despite commencing elective bi-level positive airway pressure ventilatory support, he was unable to sustain adequate gas exchange. The reduced tone of his facial muscles was addressed with the use of a chinstrap. However, an anatomical jaw malocclusion could not be remedied and he declined ventilation via a mouthpiece. He sustained marked air leakage at the mouth, such that many ventilator delivered breaths did not result in adequate ventilatory support, as seen by limited chest and abdominal excursion (Fig. 9). He was advised to consider an elective tracheostomy, but relocated and was lost to follow-up. Ultimately he agreed, at his new location, to have mouthpiece ventilation and he has remained stable. 

OHS may present with various possible sleep respiratory patterns (obstructive apneas, hypoventilation, and sometimes, central apneas, or a combined pattern) (7) and needs polysomnographic evaluation to adapt the ventilatory treatment, which is then mandatory (Fig. 3) either as nasal continuous positive airway pressure (nCPAP) or bi-level positive airway pressure ventilation, generally with oxygen supplementation if severe desaturation is present. 

Schafer H, Ewig S, Hasper E, et al. Failure of CPAP therapy in obstructive sleep apnoea syndrome predictive factors and treatment with bi-level positive airway pressure. Respir Med... 

Extubation to continuous high span bi-level positive airway pressure or, jaeferably, to NIPPV via mouth/nasal interface, no supplemental oxygen. 

Abbreviations-. Sp02, saturation of oxygen in arterial blood NIPPV, noninvasive intermittent positive pressure ventilation MAC, mechanically assisted cough CO2, carbon dioxide IPAP, inspiratory positive airway pressure BiPAP, bi-level positive airway pressure. 

Casanova et al., in a one-year study (145), randomized 52 COPD patients to standard care or standard care plus NIV with outcomes that included rate of acute exacerbations, hospital admissions, need for intubation and mortality at three, six, and 12 months. Bi-level positive pressure in spontaneous mode was implemented at an expiratory positive airway pressure of 4 cmH20 and an inspiratory positive airway pressure level of 12 cmH20, adjusted to decrease dyspnea and accessory muscle use. Five of the NIV group (total n = 26) did not tolerate it and the remainder used it for 6.2 hours per 24 hours, with only a few using it for less than 3 hr/day. One-year survival was similar between groups, as was the number of exacerbations. The breathlessness scores decreased in the NIV group, but only one psychomotor test improved. There was no evidence that the results were better in more hypercapnic patients (Paco2 > 7.3 kPa) or in those who used NIV for >5 hours per 24 hours. 

The variable controlled during the expiratory phase is known as the baseline variable, most commonly, pressure, typically expressed as EPAP or PEEP. It is necessary to have a positive baseline pressure in bi-level devices to assure CO2 washout. Bi-level devices have also been shown to be effective in managing upper airway collapse, in patients with obstructive sleep apnea and overlap (14). Einally, a positive baseline pressure has been shown to decrease the work of breathing associated with intrinsic PEEP and improve... 

Bi-level NIV may be used as a first-line treatment, with supplemental oxygen (27). Expiratory airway pressure is titrated to control h5q)opneas and apneas, and inspiratory airway pressure is added to control Paco2. If bi-level NIV fails, nasal volume ventilation may be used (29). In many patients with OHS and predominant OSA, once hypercapnia has improved (which may take several weeks) nCPAP may be used (29). Thirteen obese patients (n = 13) with a BMI > 35, aged 28-69 years with severe OSAS and hypercapnia (8.2 0.3 kPa) and failing to respond to initial CPAP therapy, were treated via a nasal nocturnal volume-cycled ventilator, which was tolerated by all patients. Significant improvements in daytime arterial blood gas levels were obtained after 7 to 18 days of nasal intermittent positive pressure ventilation (29) in 10 of the 13 patients three months later, 12 of the 13 patients could be converted to nCPAP therapy and one patient remained on NIV. In another study (37), the same results were observed after three months of home nocturnal bi-level NIV in seven patients, three of whom had severe obesity. 

Waldhom RE. Nocturnal nasal intermittent positive pressure ventilation with bi-level airway pressure (BIPAP) in respiratory failure. Chest 1992 101 516-521. 

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