BiPAP - Terminology Modes of ventilation (S) – Spontaneous; all breaths triggered by patient (T ) – Timed; all breaths initiated by machine ( S/T ) – Spont/Timed: Spontaneous unless no breath for a time period of 60/T ( AVAPS ) – Average Volume Assured Pressure Support
BiPAP - Terminology Triggering – the parameter that terminates expiration, switching from EPAP ► IPAP Cycling – the parameter that terminates inspiration, switching from IPAP ► EPAP
NIPPV: Synchronization
BiPAP - Terminology • Rise Time – rate of rise of IPAP • IPAPmax- maximal inspiratory (IPAP) time for termination in case of cycling failure • IPAPmin – minimal inspiratory ( IPAP) time in case of premature cycling
NIPPV: Synchronization
BiPAP - Terminology • Leak – amount of air leaking from the system. Intentional Leak- obligatory for mask washout to prevent CO2 rebreathing Non intentional leak – from mouth or around the mask. Undesirable to patient and system
Nasal Masks Pro: less risk of aspiration easy to fit easier secretion clearance easier speech may be able to eat less claustrophobia less dead space Con: mouth leak
Face Masks Pro: better oral leak control more effective in mouth breathers Con: increased aspiration risk asphyxiation with ventilator malfunction increased dead space
Possible Mechanism of NIPPV Benefit • Rest of chronically fatigued respiratory muscles • Improved V/Q matching • Resetting of central chemosensitivity to CO2 • Improved sleep duration and quality
Goals of NIPPV Improve gas exchange Alleviate symptoms Improve sleep quality Improve quality of life Avoid complications Avoid hospitalization Prolong survival
הל"פ ביתית התאמה • היכן לבצע את תהליך ההתאמה )מסגרת(: באשפוז במסגרת ייעודית ביןכותלי בי"ח מרפאת ) BiPAPאשפוז יום( מעבדת שינה בית המטופל• פרמטרים להחלטה על המסגרת הנאותה: חומרת המחלה הנשימתית קצב התקדמותה קיום comorbidities מיומנות ידנית של המטופל רצונו של המטופל
NIPPV COMPLICATIONS Minor and frequent: •skin ulcerations •nasal congestion •mucosal dryness •sinus/ear pain •eye irritation •claustrophobia •gastric distension
NIPPV COMPLICATIONS Major and less frequent •hypotension •aspiration •pneumothorax
INITIATION of NIPPV • Increase IPAP to achieve VT ~ 10 ml IBW • Initial EPAP ~ 4-5 cmH2O • In COPD, EPAP may be increased gradually to 7- 8 cmH2O to counteract PEEPi • Mode TRD – S/T COPD – S or S/T • Ascertain patient- ventilator synchrony
Acclimatization to NIPPV • The time following set-up and initiation • Patient role: nocturnal +/- diurnal use • Physician role: further tuning based on: patient’s subjective blood gases results (lowering PCO2)
“ during mechanical ventilation the respiratory system is affected by 2 pumps: the ventilator controlled by the physician and the patient’s own respiratory muscle pump. Patient-ventilator interaction is an expression of these 2 controllers, which should work in harmony (synchrony) for optimal results”
Deleterious Effects of P – V Asynchrony increased work of breathing muscle fatigue gas exchange patient discomfort patient compliance sleep disturbance
Salient Features of P – V Asynchrony • Worsening dyspnea • Use of accessory muscles • Non-triggering breaths
Factors affecting P –V Synchrony Ventilator variables: Triggering Cycling Rise time Mode
• Patient variables: PEEPi Pathology of resp system Pain, splinting Sedation
Dynamic Hyperinflation and PEEPi
Dynamic Hyperinflation • Lung emptying is slowed and expiration is interrupted by the next inspiratory effort, before the patient has reached the static equilibrium volume. (EELV > FRC) • dynamic hyperinflation is affected by Vt, Te, Rexp, Clung
PEEPi (autoPEEP) • Due to the incomplete empting of the lungs before the next inspiration (Dynam. Hyperinflation) alveolar pressure is > 0. • This positive Palv is called PEEPi
Salient Features of P – V Asynchrony • Worsening dyspnea • Use of accessory muscles • Non-triggering breaths
Non Triggering Breaths During NIPPV Due to PEEPi
Counteracting PEEPi by Application of EPAP During NIPPV
