BÀI GIẢNG DÀNH CHO SINH VIÊN Y KHOA, BÁC SĨ, SAU ĐẠI HỌC Introduction to invasive BP monitoring Understanding of what is required Introduction to waveform analysis Understanding of potential complications Understanding of the care & safety issues of Arterial lines
Arterial Lines Peter Branfield Aims & Objectives Introduction to invasive BP monitoring Understanding of what is required Introduction to waveform analysis Understanding of potential complications Understanding of the care & safety issues of Arterial lines Arterial Blood Pressure (BP) Pressure exerted on arterial wall Determined by flow & resistance BP=SV X HR X SVR MAP more accurately indicates perfusion MAP = (SBP – DBP)/3 + DBP Automated Non-invasive BP Most common method – Oscillometry – Measures blood flow induced oscillation Cuff with dual pneumatic & sensing channels Controlled stepped deflation Blood flow causes vibrations – Sensed as pressure changes & analysed Automated Non-invasive BP Can be uncomfortable Pressure risk Occlusion of infusions Important to get the size right Least useful when most needed Greater frequency & accuracy needed in ICU Invasive Blood Pressure -Why? Continuous measurement of BP – Cardiovascular instability – Inotropes or vasodilators – NIBP difficult or inaccurate Multiple arterial blood samples (Lough 1987) Greater accuracy -the gold standard Visual display What Cannula – Flow stop (20g) – Arrow – PiCCO Non-compliant manometer tubing Transducer Pressurised flush bag Pressure Transducers Turns a pressure signal into an electrical signal – Piezoresistive stain gauge Single transducer costs £10:50 Safe draw £13:68 Pressure Transducers Requires correct setting up – Continuous fluid pathway – No air bubbles – Non-compliant manometer tubing – Zeroed to atmospheric pressure – Level with the phlebostatic axis – No additional tubing Death by Arterial Line 85 yr, 3/52 ICU for MOF Suddenly unconscious @ 13.00hrs – ? Stroke CT 17.45 normal Laboratory Blood glucose 19.00 =0.1mmol/L Neuroglycopenic brain damage remained comatose Glucose put up as flush solutioncontaminated samples Nursing Care What you think are the Key issues for the nursing care of a patient with an arterial catheter? minutes to discuss Nursing Care (1) Nursing care mainly directed to preventing complications Ensure that the insertion site is visible at all times – This may not be possible with femoral-sited arterial lines – To ensure early detection of disconnection or leaking from site – To maintain patients dignity Nursing Care (2) All connections must be secured with luer locks – To prevent accidental disconnection Ensure that the cannula site is covered with an appropriate dressing – To maintain asepsis Place a label reading “Arterial line” next to the sampling three-way tap – To ensure correct identification of the arterial line Nursing Care (3) Never inject anything into an arterial cannula or arterial line – Concentration of a drug into the tissues served by the cannulated artery can result in cell death – skin necrosis, severe gangrene, limb ischemia, amputation & permanent disabilities Accidental Arterial Injection Immediate discomfort (seconds) – Local irritation to intense pain Cutaneous manisfestations – Flushing, mottling Sensory problems (minutes) – Tinkling, burning Altered motor function – Muscle contractures, weakness Accidental Arterial Injection Week later – – – – – Pluselessness Pain Cyanosis or pallor Paraesthesia paralysis Permanent functional deficits – Chronic pain – Depression – Inactive lifestyle Nursing Care (4) Ensure that the flush bag has adequate fluid Use only 0.9% sodium chloride Ensure that the pressure in the pressure bag is maintained at 300mmHg Do not allow the flush bag to empty – – – – – To maintain patency of arterial cannula To prevent air embolism To maintain accuracy of blood pressure reading To maintain accuracy of fluid balance chart To prevent backflow of blood Nursing Care (5) Use only the manometer tubing supplied with the transducer set – Tubing is rigid and non compliant & correct length Observe for & remove air bubbles – To ensure accuracy in measuring blood pressure Air unlike fluid is compressible as a result the pressure waveform will be dampened For children under ten years of age use a syringe driver instead of the flush bag – To prevent fluid overload Nursing Care (6) Monitor colour & temperature of limb distal to arterial line & compare to other limb – To confirm that circulation to the limb is adequate – To ensure the early detection of impaired circulation Nursing Care (7) Monitor and display the arterial waveform at all times – To detect cannula disconnection Rezero transducer once per shift – To ensure accuracy in measuring blood pressure Explanation to patient and relatives Nursing Care (8) Maintain the transducer level with the patient’s phlebostatic axis (fourth intercostal space midaxillary line) – To ensure accuracy in measuring blood pressure In patients with ICP monitoring it is appropriate to level the transducer to the tagus of the ear – In order to correctly calculate cerebral perfusion pressure (CPP) Nursing Care (9) On removal of arterial cannula maintain pressure over puncture site for at least minutes until bleeding has stopped – To prevent bleeding and haematoma formation Send cannula tip to microbiology – Only if suspected infection – To detect infection Nursing Care (10) Change the transducer set only when the cannula is resited – To reduce the risk of infection References Ahrens, T (1994) Ask the Experts Critical Care Nurse,14 (6), 98-99 Anderson, L.E (Ed.) (1998) Mosby’s medical, nursing, and allied health dictionary (5th Ed.) St Louis: Mosby Campbell, B (1997) Arterial waveforms: Monitoring changes in configuration Heart and Lung, 26 (3), 205-215 Chulay, M (1995) Ask the experts Critical Care Nurse, 15 (2), 108 Chulay, M., & Holland, S (1996) Ask the experts Critical Care Nurse, 16 (6), 103-107 Chulay, M., & Holland, S (1997) Ask the experts Critical Care Nurse, 17 (3), 14-16 Gamby, A., & Bennett, J (1995) A feasibility study of the use of non-heparinised 0.9% sodium chloride for transduced arterial and venous lines Intensive and Critical Care Nursing, 11 (3), 148 – 150 Daily, E., & Schroeder, J (1995) Techniques in bedside hemodynamic monitoring (5th ed) St Louis: Mosby Darovic, G., Vanriper, J., & Vanriper, S (1995) Arterial pressure monitoring In Darovic, G (Ed.), Hemodynamic Monitoring: Invasive and noninvasive clinical application (pp.177-210) Philadelphia: W.B Saunders Company Darovic, G., & Vanriper, S (1995) Fluid filled monitoring systems In Darovic, G., (Ed.), Hemodynamic monitoring: Invasice and noninvasive clinical application (pp.149-175) Philadelphia: J.B.Lippincott Company Gavenstein, G., Paulus, J., & Paulus, D (1987) Clinical monitoring practice (2nd ed.) Philadelphia: J.B.Lippincott Compnay Hudak, C (1998) Assessment: Cardiovascular system In Hudak, C., Gallo, B., & Benz, J (Eds.), Critical Care Nursing: A holistic approach (5th ed.) (pp.124-135) Philadelphia: J.B Lippincott Company Lough, M (1987) Introduction to hemodynamic monitoring The Nursing Clinics of North America 22 (1), 89103 National Patient safety Agency Rapid Response Report Npsa/2008/Rrr06 Problems with infusions and sampling from arterial lines 28 July 2008 Sen S, Chini E N, Brown M J (2005) Complications After Unintentional Intra-arterial Injection of Drugs: Risks, Outcomes, and Management Strategies Mayo Clinic Proceedings.;80:783-795 ... Large limb artery – Radial – Brachial – Axillary – Doralis Pedis – Femoral Usually the radial artery Normal Waveform Critically damped (correctly) – Return to waveform immediately after flushing... or high SVR Slow systolic upstroke – Poor myocardial contractility – high SVR Waveform Analysis (3) Marked respiratory swing – Hypovolaemia – Pericardial effusion – Airway obstruction Waveforms... Analysis (1) Notches – Dicrotic notch • Closing of the aortic valve • Further along in hypovolaemia – Anacrotic notch • Severe aortic stenosis Waveform Analysis (2) Short systolic time – Hypovolaemia