oxygen therapy faisal malmstrom, critical care department skmc
Post on 16-Dec-2015
225 Views
Preview:
TRANSCRIPT
Oxygen TherapyOxygen Therapy
Faisal Malmstrom,Faisal Malmstrom,
Critical Care DepartmentCritical Care Department
SKMCSKMC
ABCABC
Air goes in and out, blood goes round Air goes in and out, blood goes round and round. and round.
Any variation on this is a bad thing.Any variation on this is a bad thing.
Airway obstruction needs to be Airway obstruction needs to be addressed immediately addressed immediately
Respiratory failureRespiratory failure
Type 1 (hypoxemic) Type 1 (hypoxemic)
Saturation Saturation < 90%. PaO< 90%. PaO2 2 <60 mm Hg<60 mm Hg
Type 2 (hypercapnic)Type 2 (hypercapnic)
PCOPCO22>50 mmHg, pH<7.35>50 mmHg, pH<7.35
HypoxemiaHypoxemia
Low alveolar oxygen tensionLow alveolar oxygen tension
(ambient, hypoventilation)(ambient, hypoventilation) Ventilation-perfusion mismatchVentilation-perfusion mismatch Right to left shunt (venous admixture)Right to left shunt (venous admixture)
intracardiacintracardiac
extracardiacextracardiac Impaired oxygen diffusion (uncommon)Impaired oxygen diffusion (uncommon)
V/Q mismatchV/Q mismatch
Ventilated but not perfused: increased Ventilated but not perfused: increased dead space ventilation, VT=dead space ventilation, VT=VDVD+VA+VA
VD= VD= VD VD equipment equipment + VD+ VD anatomic anatomic + VD + VD physiologicphysiologic
Perfused but not ventilated: shuntPerfused but not ventilated: shunt
>20% Shunt fraction, minimal >20% Shunt fraction, minimal improvement with increased FiO2improvement with increased FiO2
Hypoxia Hypoxia
Hypoxemic HypoxiaHypoxemic Hypoxia Anaemic HypoxiaAnaemic Hypoxia Stagnant Hypoxia ( distributive or low Stagnant Hypoxia ( distributive or low
CO)CO) Histotoxic Hypoxia Histotoxic Hypoxia
VDO2VDO2= CO x Hb x SAT/100 x 1.34ml/gHb+ = CO x Hb x SAT/100 x 1.34ml/gHb+ (PaO2 x 0.003mlO2/100ml/mmHg)(PaO2 x 0.003mlO2/100ml/mmHg)
Symptoms of Hypoxemia Symptoms of Hypoxemia and Hypoxiaand Hypoxia
Dyspnea, tachypnea. HyperventilationDyspnea, tachypnea. Hyperventilation +/- Cyanosis ( Hb, perfusion) >15g/l+/- Cyanosis ( Hb, perfusion) >15g/l Impaired mental performance----comaImpaired mental performance----coma Seizures, permanent brain injurySeizures, permanent brain injury Tachycardia/Hypertension – Tachycardia/Hypertension –
Hypotension/Bradycardia( 30 mmHg)Hypotension/Bradycardia( 30 mmHg) Lactic acidosisLactic acidosis
Indications for Oxygen Indications for Oxygen therapytherapy
Cardiac and respiratory arrestCardiac and respiratory arrest Hypoxemia ( pO2 < 58.5 mmHg, Hypoxemia ( pO2 < 58.5 mmHg,
Sat<90%)Sat<90%) Hypotension ( Systolic BP < 100 mmHg)Hypotension ( Systolic BP < 100 mmHg) Low Cardiac Output and Metabolic Low Cardiac Output and Metabolic
Acidosis ( bicarbonate <18 mmol/l)Acidosis ( bicarbonate <18 mmol/l) Respiratory distress ( RR>24/minute)Respiratory distress ( RR>24/minute)American College of Chest Physicians and NHLBI American College of Chest Physicians and NHLBI
Treatment ITreatment I
EmpiricEmpiric oxygen treatment oxygen treatment
Cardiac/ respiratory arrestCardiac/ respiratory arrest
HypotensionHypotension
Respiratory Distress Respiratory Distress
TraumaTrauma
GCS decrease from any causeGCS decrease from any cause
Postoperative Postoperative
Treatment IITreatment II
Verify hypoxemiaVerify hypoxemia
Pulse oximetry Pulse oximetry
ABG’sABG’s Start Oxygen treatment.Start Oxygen treatment. Treatment goal ( sat level)Treatment goal ( sat level) Administration mode, flow, when to stop Administration mode, flow, when to stop
Copyright ©2006 BMJ Publishing Group Ltd.
Currie, G. P et al. BMJ 2006;333:34-36
The oxyhaemoglobin dissociation curve showing the relation between partial pressure of oxygen and haemoglobin saturation
Copyright ©2000 BMJ Publishing Group Ltd.
Dodd, M E et al. BMJ 2000;321:864-865
Charting Oxygen treatment
Bad medicineBad medicine
To withhold Oxygen out of fear of hypercarbic To withhold Oxygen out of fear of hypercarbic ventilatory failure is poor practiceventilatory failure is poor practice
Identify patients at risk (COPD)Identify patients at risk (COPD)
Use Venturi masks 0.24 -0.28 ---- FiO2.Use Venturi masks 0.24 -0.28 ---- FiO2.
ABG’s/ O2-sat to direct therapyABG’s/ O2-sat to direct therapy
Support ventilation (BiPAP, intubationSupport ventilation (BiPAP, intubation))
Oxygen HazardsOxygen Hazards
Fire ( airway fires) Fire ( airway fires) Tissue toxicity, pulmonary and retinaTissue toxicity, pulmonary and retina Decreased hypoxemic drive and Decreased hypoxemic drive and
increased VDincreased VD in COPD. in COPD. Seizures (hyperbaric)Seizures (hyperbaric) Mucosal damage due to lack of humidityMucosal damage due to lack of humidity
Oxygen administrationOxygen administration
Low flow systemsLow flow systems
High Flow systems (HFOE)High Flow systems (HFOE)
Copyright ©2006 BMJ Publishing Group Ltd.
Currie, G. P et al. BMJ 2006;333:34-36
Long term oxygen therapy prolongs survival in hypoxaemic patients with COPD when used for ≥15 hours/day. (Results from the nocturnal oxygen therapy trial (NOTT) and the MRC trial)
Take home messageTake home message
Acute empiric oxygen treatment is ok but hypoxemia Acute empiric oxygen treatment is ok but hypoxemia should be verified with pulse oximetry and /or ABG’s should be verified with pulse oximetry and /or ABG’s when situation more stable.when situation more stable.
Oxygen is a drug and should be ordered as such: Oxygen is a drug and should be ordered as such: mode of administration, flow rate, FiO2 (venturi), mode of administration, flow rate, FiO2 (venturi), treatment goal, monitoring, when to stop.treatment goal, monitoring, when to stop.
Never withhold oxygen out of fear of possible Never withhold oxygen out of fear of possible hypercarbiahypercarbia
Avoid overzealous treatment- Adequate saturation for Avoid overzealous treatment- Adequate saturation for the patient. COPD 88-90%the patient. COPD 88-90%
top related