Permissive Hypercapnia
-Therapeutically allowing the PaCO2 to increase and the ph to drop to acidosis by limiting ventilatory support
-Allow PaCO2 to rise above normal (e.g greater than 50) and Ph values are allowed to fall below normal (e.g, greater than equal to 7.10-7.30) -Lung protection strategy to avoid overdistension and acute lung injury (prevent damage to the alveoli)
Permissive Hypercapnia
-Indications
-Anytime Pplat is rising -<30 cmH2O
Permissive Hypercapnia
-Contraindications
-Contraindications
-Presence of disorders such as head trauma, hemorrhage, CNS lesions and intracranial disease -Increased PaCO2= cerebral vasodilation= increased ICP -Pt with cardiovascular instability -Increased PaCO2 and decreased pH may lead to decreased myocardial contractility, arrhythmias and vasodilation
Permissive Hypercapnia
-Management
-Remove sources odd mechanical dead space
-Ventilate with a low VT (4-7 lm/kg IBW) -INcrease the frequency of mandatory breaths -Goal to keep Pplat <30 cmH2O
Chronic Obstructive Pulmonary disease
-Non-invasive strategies
-Non-invasive strategies
-Benefit from using NIV as first line intervention to reduce mortality and the need for intubation -Suggested Non invasive settings -IPAP= 10cmH2O -EPAP=5 cmH2O -FiO2 = <50 when possible but do not under treat clinical hypoxia -Totrate to clinical goals (CO2,O2,WOB) and tolerance
Chronic Obstructive Pulmonary disease
-Invasive
-Suggested settings
-Vt 6-8 ml/kg IBW keep Pplat <30
-F- 8-16 breaths per min, lower may be best to ensure full exhalation -Ti- .6-1.2 seconds, lower Ti, I:E ratio=1.4-1.6 -Flow 60-100 L/min
Chronic Obstructive Pulmonary disease
-Weaning
-Weaning can be challenging- my need to extubate to NPPV (may not have perfect weaning parameters)
Asthma
-Non invasive management
-May be useful short term/ trial allow for steroids and bronchodilators to become effective
-Limitations- increases risk of aspiration and high risk of auto PEEP
Asthma
-Non invasive management
-CPAP
-CPAP- when FiO2<.70 and PaCO2 < 50mmHg
-Begin CPAP at 5 cmH2O and titrate SPO2, FiO2 100% and wean as clinically indicated
Asthma
-Non invasive management
-BiPAP
-BiPAP when FiO2> .70 and PaCO2 > 50mmHG
-IPAP 8-10, EPAP 3-5 -Maintian driving pressure of at least 5 cmH2O -Failure to improve after a short trial may be an indication for intubation
Asthma
-Invasive management
-Suggested vent settings
-Vt- -8 ml/kg IBW , keep PIP < 40 and PPLat <30
-Ti, .75-1.2 seconds, Te is adequate for exhalation, I:E ratio = 1:3 =1:5
-Heliox (Heliox driven albuterol treatment) or magnesium sulfate may be considered to avoid intubation
Neuromuscular Disorders
-Monitoring
-Pulmonary mechanics, Vt,VC, MIP/NIF
Neuromuscular Disorders
-Non invasive strategies
-Access airway patency, secretion management
-NIF may indicate need of invasive support
Neuromuscular Disorders
-Invasive strategies
-Vt 6-8 ml/kg may be necessary to use Vt at 8ml/kg and possibly higher, keep PPLat <30
-Ti < 1 sec -PEEP 5 to maintain RC -FiO2 minimal once lungs are recruited
Head trauma or Closed head Injury
-Normal values
-Cerberal perfusion pressure (CCP)( 70-90 mmHG
-Defined by equation: CPP=MAP-ICP -CPP<60 mmHG indicate poor cerebral perfusion -Intercranial pressure (ICP) 5-10 mmHg -Mean Arterial Pressure 90-95
Head trauma or Closed head Injury
-Glasgow Coma Scale
Lower the number the worse the pt the higher the better
Head trauma or Closed head Injury
-Invasive strategies
-VT 6-8 ml/kg Keep pplat <30
-Ti <1 sec -Flow high to keep Ti short -PEEP < 5 PEEP can increase ICP and is used only if necessary to avoid severe hypoxia **-FiO2 1.0 initially and titrate s needed to keep PAO2 from 70-100 mmHG to avoid Hypoxemia, hypoxia can further injury ** -Note suctioning and CPT can increase ICP, but maintaining a clear, patient airway is essential, use with cautions
Head trauma or Closed head Injury
-Iatrogenic hyperventilation
-Maintain normal eucapnic ventilation unless ICP is uncontrolled and >20 mmHG
-Iatrogenic hyperventilation, deliberate lowering a PaCO2 25-30 mmhg -acute reductions in PaCO2 results in cerebral vasoconstriction , reducing cerebral blood volume and reducing ICP -Avoid hyperventilation in the first 24 hours after injury, just suggested
Head trauma or Closed head Injury
cushing response
-Sudden increases in PACO2 could trigger increases in cerebral blood flow and ICP
-A normal response to acute increase in ICP is hypertension with bradycardia -Called cushing response
Acute Cardiogenic Pulmonary Edema or Congestive Heart Failure (CHF)
-Noninvasive strategies
-NPPV should be considered if accompany acute hypercapnia
-CPAP 10-15 ccHG -MAy help reduce preload, reduce left ventricular afterload and prevent alveolar collapse and end extubation -FiO2 1.0 then wean down
Acute Cardiogenic Pulmonary Edema or Congestive Heart Failure (CHF)
-Invasive strategies
-VT 6-8 ml/kg
-FiO2 1.0
-Careful evaluation of the effects of PPV on hemodynamics is essential
-PPV and PEEP can decrease venous return
Acute Respiratory Distress Syndrome (ARDS)
-Invasive strategies
-VT 6-8 ml/kg Pplat <30 cmH2O
-vt as low as 4 ml/kg be necessary -f- 12 bpm or more to maintain adequate minute ventilation -Ti .8 1.2 sec -Lengthen Ti to improve oxygenation only after Vt, f , and PEEP have been optimized -PEEP 5 or greater without causing overdistention -FiO2 as needed to achieve PaO2 target of 60 torr
-ARDS management
-Goal
-Goal is to largely protect lungs from as much damage as possible, support failing system, and treat underlaying cause
-ARDS management
-Lung protective strategies
-Maintaining Pplat <30 driving pressure <15 high pressure= pressure control
-USE LOW vt STRATEGIES, REDUCING vT 6 ML/KG POSSIBLY DOWN TO 4 ML/KG -Consider permissive hypercapines -Consider advanced vent modes, APRV, PRV, etc. -Oxygenation- refractory hypoxemia and pulmonary shunting is likely, utilize PEEP -PaO2/ FiO2 severity on PEEP > 5 mild=200-300, moderate 100-200 severe < 100
