Stroke volume variation SVV 5 % ≤ 10 %
Cardiac Index 4.68 (L/min) 3.0 – 5.0l/min/m2
Stroke Volume SV 60 (ml) 40 – 60ml/m2
Heart Rate HR 78 (beats/min) 60-90/min
Blood Temperature 38.2[°C] 36.2-37.2[°C]
Global End Diastolic Volume 460 (ml)
The above variables were used as guide for rate of Noradrenaline infusion and fluid administration. ABG immediately after PiCCO studies was; FI02 60%, PH7.3, PC02 6.5kpa, PO2 12.2kpa, HC03 24.6mmol/l, BASE –1.2, K+ 4.0mmol/l, S02 98.6%, HB 10.6g/dl, NA 132mmol/l, Pso2 of 97% with capillary refill within 2 seconds.
%
PiCCO flows monitoring is different from other haemodynamic monitoring devices because it offers a continuous Cardiac output measurement combined with Cardiac Preload volume, and Lung water monitoring without the need for a pulmonary artery catheter. (Sakka et al (2000)
The following volume of iced 0.9% NACL or 5% Glucose is recommended.
Kg body weight Iced injection volume (ml)
< 3 2mls
< 10 3mls
< 25 5mls
< 50 10mls
< 100 15mls
> 100 20mls
The injection volume should be done as fast (< 5 sec) and as steadily as possible and calibration is recommended every four hours. ()
Five hours latter, I noticed that Mr Benedict’s extremities were becoming blue compared to his warmed and pinked skin colour thirty minutes ago. The Arterial Blood pressure on the monitor was 132/73 mmHg (with mean arterial pressure of 70mmHg), HR 73; ABG was taken and read as follows FI02 60%, PH7.32, PC02 4.6kpa, PO2 11.25kpa, HC03 26.0mmol/l, Base Excess –1.0mmol/l, S02 97%, K+ 3.9mmol/l, HB 9.5g/dl, NA 132mmol/l, Ps02 was non-recordable, the capillary refill was more than five seconds, and the extremities were becoming colder. The Anaesthetist Registrar on call was informed and on arrival he opted for another PiCCO studies because the last studies was done five hours ago and to confirm Mr benedict’s Systemic Vascular Resistance (SVRI).
Experience Anaesthetist or experience Senior Nurses normally performs PiCCO flow studies in our Intensive Care Unit. The Anaesthetist Registrar on this occasion performed the calibration and injection of fluid. The fluid he used for calibration was at room temperature and the volume was 20mls (instead of 15mls that was the recommended volume for Mr Benedict’s weight). The results were as follows:
Parameters Actual Normal Range
Arterial Blood Pressure 130/92 (mmHg)
Mean Arterial Pressure 75(mmHg) 70 – 90mmHg
Pulse pressure 53 (mmHg) 30-50mmHg
Index of left ventricular contractility 709 (mmHg/sec)
Systemic Vascular Resistance SVRI 2 1028 (dyn-sec-cm5) 1200 – 2000dyn*s*cm-5*m2
Stroke volume variation SVV 5 % ≤ 10 %
Cardiac Index 4.68 (L/min) 3.0 – 5.0l/min/m2
Stroke Volume SV 70 (ml) 40 – 60ml/m2
Heart Rate HR 108 (beats/min) 60-90/min
Blood Temperature 37.2[°C] 36.2-37.2[°C]
Global End Diastolic Volume 440 (ml)
From the above studies the SVRI and Stroke volume were below the normal range: if those values were relied on, rate of nonadrenaline would go up from 18mcg/minute with additional fluid challenge, the rate was not increased and there was no fluid challenge.
Comparison of Arterial Blood Pressure displayed on PiCCO flow monitor could not be made with the main monitor because the Arterial trace was not steady and different from non-invasive Blood Pressure.
I suggested to the Anaesthetist Registrar that the injected fluid’s temperature and the volume might have influenced the result, I expected the SVRI to be higher than 1200(dyn-sec-cm5) because of Ps02 was non-recordable and the capillary refill was poor, and the extremities were cold and cyanosed.
ACTION PLAN
I have assisted Consultants and Senior Nurses during PiCCO studies and on all those occasions the manufacturer’s instructions were strictly followed.
I made my feelings known to the Anaesthetist Registrar, but he did not feel my observations about the Temperature and volume of injected fluid would influence the result.
Five minutes later, our Consultants Anaesthetist came into the Unit, and he was informed about the patient’s condition. He repeated the haemodynamic studies with manufacturers instructions strictly followed, and the result were as follows:
Parameters Actual Normal Range
Arterial Blood Pressure 160/102 (mmHg)
Mean Arterial Pressure 92 (mmHg) 70 – 90mmHg
Pulse pressure 53 (mmHg) 30-50mmHg
Index of left ventricular contractility 1390 (mmHg/sec)
Systemic Vascular Resistance SVRI 2 2324 (dyn-sec-cm5) 1200 – 2000dyn*s*cm-5*m2
Stroke volume variation SVV 5 % ≤ 10 %
Cardiac Index 4.68 (L/min) 3.0 – 5.0l/min/m2
Stroke Volume SV 70 (ml) 40 – 60ml/m2
Heart Rate HR 108 (beats/min) 60-90/min
Blood Temperature 38.2[°C] 36.2-37.2[°C]
Global End Diastolic Volume 460 (ml)
Further clinical decision was made, based on the above result. Noradrenaline was reduced.
FEELINGS
After the Noradrenaline rate was reduced, the mean arterial pressure came down to; the colour of sink gradually turned pink and the pulse oximetry became recordable (94%). I felt happy within me because had it been that the rate of the nonadrenaline was not reduced the feet and hands of Mr Benedict might become gangrenous. The Pulse Contour Cardiac Output (PiCCO) flow, though an innovative technology that monitors the cardiac preload volume through the global end diastolic volume (GEDV) and gives an estimation of the intra-thoracic blood volume through a `beat to beat' analysis of the arterial pressure wave and measures continuous cardiac output, but it is important that manufacturer’s instructions are strictly followed otherwise the results would be inaccurate (Rocca et al (1999).
EVALUATION
Good understanding of measures and calculated values, and knowing how to identify errors in measurement and signal transduction are crucial to the use of PiCCO. Errors can occur during haemodynamic studies, and obtaining accurate cardiac measurements requires good thermo-dilution technique.
Oversights and inappropriate ways of performing procedures would make results inaccurate, which in many cases will result in decisions that are of no value to the patient, increase patients length of stay in ICU, increase the relatives anxiety, demoralise the nursing staff, and waste of human and financial resources (Jevon &Ewen 2002).
The most positive thing about this incident was that, our Consultant gave a brief lecture on the PiCCO study with the Registrar in attendance.
After this episode, I read through the PiCCO manual with great interest and I was able to understand the history of PiCCO and how PiCCO studies can influence clinical decisions and the significance of the variables.
CONCLUSION
Knowledge, assessment and monitoring of haemodynamic parameters such as Pulse pressure variation PPV, Index of left ventricular contractility, Systemic Vascular Resistance SVR, Stroke volume variation SVV, Cardiac Index, Stroke Volume SV, SVRI, cardiac output (CO) and pulmonary artery pressures (PAPs) may aid in fast diagnosis and treatment of the patient and help guide the management of critically ill patients (Darovic 2002). The calibration performed by the anaesthetist Registrar was inaccurate possibly because of inexperience and non-compliance with manufacturer’s instruction.
The PiCCO parameters are determined both intermittently through trans-pulmonary thermo-dilution technique and continuously through arterial pulse contour analysis (Johnston 1997).
If this situation arises again, I will refer who ever it may be concerned to manufacturer’s manual.
Proper assessment of patients requires understanding of how measured values differ from predicted values and knowing how to identify errors in measurement and signal transduction. Improper positioning of the patient, volume and temperature of injection fluid, incorrect calibration or balancing of the transducer can render measurements invalid and make management of patient unrewarding. (Darovic 2002)
The last calibration performed by the Consultant was accurate because of the consultants past experiences and his compliance with manufacturer’s instruction.
References:
Darovic G (2002) Haemodynamic Monitoring: Invasive and Non-invasive Clinical Application. Elsevier Science
G Delia Rocca, L Pompei, C Coccia, MG Costa, F Ruberto and F Pugliese (6-19 March 1999) PiCCO monitoring during anaesthesia 19th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium.
GIBBS model (1988)
Harris RS, Hess DR, Venegas JG (2000). An objective analysis of the pressure-volume curve in the Acute respiratory distress syndrome. Am J Respir Critical Care Med 2000; 161
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Jevon &Even (2002a), (2003b) Monitoring the critically ill patients. Blackwell Science
Johnston R (1997) International handbook of Intensive Care Euromed Communications Ltd
Matthay MA, Chatterjee K (1988) Bedside catheterization of the pulmonary artery: risks compared with benefits. Ann Intern Med 109:826-34.
Nursing and Midwifery Council UK (2002).
Swan HJC, Ganz W J Am Coll Cardiol (1983). Hemodynamic measurements in clinical practice: A decade in review. J Am Coll Cardiol 1983; 1: 103-13.
Sharkey W (1997) . Lippincott Williams & Wilkins
Sakka SG, Reinhart K, Meier-Hellmann A (2000) Is the placement of a pulmonary artery catheter still justified solely for the measurement of cardiac output? : J Cardiothoracic Vacs Anaesthesia. 2000 Apr; 14(2): 119-24.
