Knowing and understanding the different normal values is important for making informed clinical decisions as a respiratory therapist.

Because if a patient’s results fall outside of the normal range, it may be indicative of a problem or disease that needs to be further investigated.

Therefore, if you do not know the normal values ranges, how are you supposed to know the best action to take for each patient?

This reference guide will provide you with the most common normal values that are used in the field of respiratory care.

Note: Please keep in mind that what’s considered to be a normal value may vary from one publication to another. However, we have provided the most appropriate ranges to help respiratory therapy students pass the licensure board exams. This information is for educational purposes only.

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Vital Signs Normal Values:

  • Heart Rate:  60–100 beats/min
  • Respiratory Rate:  12–20 breaths/min
  • Blood Pressure:  120/80 mmHg
  • Body Temperature:  98.6˚F (37˚C)
  • Oxygen Saturation (SpO2):  > 93%

ABG Normal Values:

  • pH:  7.35–7.45
  • PaCO2:  35–45 mmHg
  • PaO2:  80–100 mmHg
  • HCO3-:  22–26 mEq/L
  • BE:  -2 – +2

Normal Lab Values:

  • Hemoglobin (Hb):  12–16 gm/dL
  • Hematocrit (Hct):  40–50%
  • Red Blood Cells:  4–6 millions/mL
  • White Blood Cells:  5,000–10,000 millions/mL
  • Creatinine:  0.7–1.3 mg/dL
  • Blood Urea Nitrogen (BUN):  8–25 mg/dL
  • Prothrombin Time:  11–15 seconds
  • Platelet Count:  150,000–400,000 units
  • Troponin:  < 0.4 ng/mL
  • Brain Natriuretic Peptide (BNP):  < 100 pg/mL

Electrolyte Values:

  • Sodium (Na+):  135–145 mEq/L
  • Chloride (Cl+):  80–100 mEq/L
  • Potassium (K+):  3.5–4.5 mEq/L

Ventilatory Values:

  • Tidal Volume (VT):  > 5 mL/kg
  • Vital Capacity (VC):  65–75 mL/kg
  • Minute Ventilation (VE):  5–8 L/min
  • Mean Airway Pressure (MAP):  5–10 cmH2O
  • Maximum Inspiratory Pressure (MIP):  > -20 cmH2O
  • Maximum Expiratory Pressure (MEP):  > +40 cmH2O
  • Rapid Shallow Breathing Index (RSBI):  < 100
  • Deadspace-to-Tidal-Volume Ratio (VD/VT):  < 60%
  • Anatomic Deadspace:  1 mL/pound of IBW
  • Cuff Pressure:  25–35 cmH2O
  • Capnography:  3–5 %
  • Intracranial Pressure (ICP):  5–10 mmHg

Hemodynamic Monitoring Values:

  • Cardiac Output:  4–8 L/min
  • Central Venous Pressure (CVP):  2–6 mmHg
  • Cardiac Index:  2–4 L/min/m2
  • Stroke Volume:  50–100 mL/beat
  • Pulmonary Artery Pressure (PAP):  25/8 mmHg
  • Pulmonary Vascular Resistance (PVR):  200 dynes/sec/cm5
  • Systemic Vascular Resistance (SVR):  1400 dynes/sec/cm5
  • Pulmonary Capillary Wedge Pressure (PCWP):  5–10 mmHg
  • Mean Arterial Pressure (MAP):  93 mmHg
  • Urine Output:  40 mL/hour

Oxygenation Normal Values:

  • SpO2:  > 93%
  • PAO2:  95–100 mmHg on room air
  • PaO2/FiO2 Ratio:  > 380
  • Shunt (Qs/Qt):  3–5%
  • CaO2:  17–20 vol%
  • CvO2:  12–16 vol%
  • C(a-v)O2:  4–5 vol%
  • PetCO2:  25–35 mmHg
  • Oxygenation Index (OI):  < 10

Pulmonary Function Testing Normal Values:

  • FEV1:  > 80% of predicted
  • FEV1/FVC%:  ≥ 70%
  • Forced Vital Capacity (FVC):  > 80% of predicted
  • Slow Vital Capacity (SVC):  > 80% of predicted
  • Airway Resistance (RAW):  0.6–2.4 cmH2O/L/sec
  • Diffusing Capacity for Carbon Monoxide (DLCO):  20–25 mL/CO/min/mmHg
  • Peak Expiratory Flow Rate (PEFR):  10 L/sec
  • Exhaled Carbon Monoxide:  < 7 for nonsmokers

Initial Ventilator Settings Normal Values:

  • Tidal Volume:  5–10 mL/kg of the patient’s ideal body weight (IBW)
  • Frequency:  10–20 breaths/min.
  • FiO2:  30–60% or the FiO2 they were previously on
  • Flow Rate:  40–60 L/min
  • I:E Ratio:  1:2–1:4
  • Sensitivity:  -1 to -2 cmH2O
  • PEEP:  4–6 cmH2O

Infant Normal Values:

  • Heart Rate:  110–160 beats/min
  • Respiratory Rate:  30–60 breaths/min
  • Blood Pressure:  60/40 mmHg
  • Body Temperature:  98.6˚F (37˚C)
  • Oxygen Saturation (SpO2):  > 90%
  • Blood Glucose:  > 30 mg/dL
  • Gestation Age:  40 weeks
  • Apgar Score:  7–10
  • Birth Weight:  ≥ 3,000 grams
  • L/S Ratio:  ≥ 2:1
  • Silverman Anderson Score:  0–1

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Final Thoughts

It’s essential for respiratory therapists to learn and understand the different normal values and the appropriate range for each.

Some of the most important types are in the following categories:

By learning and understanding the normal values for each category, you will be better equipped to provide the best possible care for your patients.

Not to mention, students must know these normal values in order to pass the TMC Exam as well. Hopefully, this guide can make the learning process a little bit easier for you. Thanks for reading!

Medical Disclaimer: This content is for educational and informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Please consult with a physician with any questions that you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you read in this article. We strive for 100% accuracy, but errors may occur, and medications, protocols, and treatment methods may change over time.

References

The following are the sources that were used while doing research for this article:

  • Egan’s Fundamentals of Respiratory Care. 11th ed., Mosby, 2016. [Link]
  • Clinical Application of Mechanical Ventilation. 4th ed., Cengage Learning, 2013. [Link]
  • Respiratory Care Calculations. 4th ed., rtexam, 2018. [Link]
  • “Interpretation of Arterial Blood Gas.” PubMed Central (PMC), 14 Apr. 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC2936733.

Disclosure: The links to the textbooks are affiliate links which means, at no additional cost to you, we will earn a commission if you click through and make a purchase.

Medical Disclaimer: The information provided by Respiratory Therapy Zone is for educational and informational purposes only. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. Please consult with a physician with any questions that you may have regarding a medical condition.