Use and Misuse of Clinical Data

Use and Misuse ofClinical DataFocus Conference

May 15, 2014

David ChangProfessorCardiorespiratory CareUniversity of South Alabama

Quiz #1The normal cerebral perfusion pressure

(CPP) is _______ . The mortality rate increases by _______ for each 10 mm Hg drop in CPP.

A. 8 to 12 mm Hg; 10%B. 8 to 12 mm Hg; 20%C. 70 to 80 mm Hg; 10%D. 70 to 80 mm Hg; 20%

Quiz #2An arterial blood gas sample was collected from a

patient with COPD 10 minutes after initiation of mechanical ventilation. The results are: pH = 7.47, PaCO2 = 40 mm Hg, HCO3- = 28 mEq/L. This ABG most likely represents :

A. Respiratory acidosisB. Respiratory alkalosisC. Metabolic acidosisD. Metabolic alkalosisE. None of the above

Quiz #3The results of an arterial blood gas sample drawn

from a mechanically ventilated patient are: pH = 7.47, PaCO2 = 33 mm Hg, PaO2 = 68 mm Hg, FIO2 = 40%. No PEEP. The therapist should:

A. decrease the frequencyB. increase the FIO2 C. decrease the frequency and increase the FIO2 D. increase the frequency and increase the FIO2 E. increase the frequency or pressure support

Quiz #4The pressure / volume loop is typically used

to evaluate a patient’s _______ status.

A. airflow resistanceB. compliance C. oxygenation D. ventilatory

Outline1. Clinical Data and Patient Care2. Types of Clinical Data3. Reasons for Using Clinical Data Correctly4. Incorrect Use of Clinical Data5. Causes of Invalid Clinical Data6. Application of Clinical Data

DataPleural of Latin datumRelated to “give” “something given”Data represent information

DataPleural of Latin datumRelated to “give” “something given”Data represent information (more than

numbers)

Clinical errors are strongly related to (1) misuse of clinical information, or (2) use of incomplete or invalid clinical information

Data EverywhereDaily: Time, newspaper, place, people,

email, TVClinical: Breath sounds, vital signs, physical

exam



Clinical Data and Patient Care1. Decision making (initiate, change,

discontinue)2. Best patient care vs. defensive medicine 3. Errors in health care in the U.S. alone

cause between 44,000 and 98,000 deaths every year (Ref: Mechanical Ventilation - H.M. 2011)

4. Non-use of patient clinical data presents a greater risk than misuse (Ref: St. Clair, 2008)



cause between 44,000 and 98,000 deaths every year (Ref: Mechanical Ventilation - H.M. 2011)




cause between 44,000 and 98,000 deaths every year (Ref: Mechanical Ventilation - H.M. 2011) (+100,000s of unreported deaths and injuries) e.g., 3 fetal errors in incorrect breath sound assessment




cause between 44,000 and 98,000 deaths every year (Ref: Mechanical Ventilation - H.M. 2011) (+100,000s of unreported deaths and injuries)



Types of Clinical Data1. Data from history and admitting workup 2. Ongoing assessment and monitoring 3. Routine and special laboratory data

(patient is passive) 4. Data from clinical procedures (patient is

active)



active)



active)



active)


Reasons for Using Clinical Data Correctly

1. Prevent harm (e.g., false-positive, false-negative)

2. Reduce malpractice3. Reduce healthcare cost4. Protect professional license5. Improve professionalism














Incorrect Use of Clinical Data1. Unfamiliar data or procedure 2. Carelessness3. Incorrect interpretation4. Incomplete information

Quiz #1The normal cerebral perfusion pressure

(CPP) is _______ . The mortality rate increases by _______ for each 10 mm Hg drop in CPP.


Quiz #1The normal cerebral perfusion pressure (CPP)

is _______ . The mortality rate increases by _______ for each 10 mm Hg drop in CPP.


CPP = MAP - ICP


Incorrect Use of Clinical DataA 34-year-old woman was incorrectly

diagnosed with a rare and aggressive form of neuroendocrine cancer. Her entire lower jaw and teeth were removed and her face was reconstructed with bones taken from lower legs, suffering permanent disfigurement. It turned out that her lab sample was contaminated with another patient’s sample.


Quiz #2An arterial blood gas sample was collected from a

patient with COPD 10 minutes after initiation of mechanical ventilation. The results are: pH = 7.47, PaCO2 = 40 mm Hg, HCO3- = 28 mEq/L. This ABG most likely represents :

A. Respiratory acidosisB. Respiratory alkalosisC. Metabolic acidosisD. Metabolic alkalosisE. None of the above

Incorrect InterpretationAn arterial blood gas sample was collected from a patient with COPD 10 minutes after initiation of mechanical ventilation. The results are: pH = 7.47, PaCO2 = 40 mm Hg, HCO3- = 28 mEq/L. This ABG most likely represents :acute respiratory alkalosis superimposed on chronic respiratory acidosis.

pH PaCO2 HCO3-

Chronic respiratory acidosis ↓ NL ↑↑ ↑↑

Acute respiratory alkalosis ↑↑ ↓↓ ↓ NL

Combined ↑ NL ↑

Incorrect Use of Clinical Data1. Unfamiliar data 2. Carelessness3. Incorrect interpretation4. Incomplete information

Quiz #3The results of an arterial blood gas sample drawn from

a mechanically ventilated patient are: pH = 7.47, PaCO2 = 33 mm Hg, PaO2 = 68 mm Hg, FIO2 = 40%. No PEEP, SIMV f = 10/min, total f = 34/min, average spontaneous VT = 120 mL. The therapist should

A. decrease the frequencyB. increase the FIO2 C. decrease the frequency and increase the FIO2 D. increase the frequency and increase the FIO2

E. increase the frequency or initiate pressure support


Causes of Invalid Clinical Data

1. Human/machine errors2. Data from incorrectly done procedures3. Missing / incomplete information

- Lab errors 1 to 3% in 1976 (Am J Med Tech, 1976)- Lab errors 3 to 5% in 2006 (Post Gazette, 2006)



- Sample mixed up- Analytical/technical errors- Inaccurate calibration and poor quality control- Incorrect auto-interpretation



- Maximal Inspiratory Pressure (MIP)- Rapid Shallow Breathing Index (RSBI)- Sputum Gram Stain or Culture-



pH = 7.47, PaCO2 = 40 mm Hg, HCO3- = 28 mEq/LNormal: Metabolic alkalosisCOPD: Acute respiratory alkalosis superimposed on chronic respiratory acidosis.

pH PaCO2 HCO3-

Chronic respiratory acidosis ↓ NL ↑↑ ↑↑

Acute respiratory alkalosis ↑↑ ↓↓ ↓ NL

Combined ↑ NL ↑


Application of Clinical DataSample must be valid - repeat if necessary

(change of FIO2 , air bubble, venous admixture, wrong settings)

Results must be valid (calibration, QA)Reporting must be complete (FIO2,

ventilator settings)Procedure must be consistent (MIP, RSBI,

FVC)Clinical data should be applied (MAP and

CPP)






CPP)






CPP)






CPP)






CPP)






CPP)






CPP)e.g., CPP = MAP - ICP

Application of Clinical Data

CPP = MAP – ICP

Brain occupies ~2% of total body weightBrain uses 15% of energy generated by the bodyBrain does not hold or store any energy of its ownBrain relies on a small amount of glycogen in the astrocytes

Low CPP reduces availability of oxygen to the brainLow CPP may lead to hypoxic-ischemic encephalopathy (HIC) e.g., patients with hypotension, CHF, COPD Energy failure (duration sensitive) may result in cerebral

cellular injury or death


CPP = MAP – ICP

CPP: Critical threshold 70 to 80 mm Hg (mortality increases about 20% for each 10 mm Hg drop in CPP below 70 mm Hg)

MAP: Keep CPP > 70 mm Hg (keep SBP > 90 mm Hg if MAP not available)

ICP: Normal 8 to 12 mm Hg, Clinical critical value < 20 mm Hg


The pressure / volume loop is typically used to evaluate a patient’s _______ status.

A. airflow resistanceB. compliance C. oxygenation D. ventilatory


Take Home Messages(1) Do not accept clinical data at face value(2) Make sure the data are technically valid

and accurate(3) Interpretation must be based on

complete data and supporting information(4) Clinical data must match patient’s

presentation(5) Use clinical information frequently and

wisely

Best wishes

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Use and Misuse of Clinical Data