PHYSIOLOGICAL PATHWAYS THAT MAY LEAD TO RESPIRATORY COMPROMISE

Multiple underlying conditions may be responsible for evolving respiratory compromise. Conditions that lead to respiratory compromise can be categorized by three physiological pathways: hypoxic respiratory failure, hypercapnic respiratory failure, and sleep disordered breathing related arousal failure.1

Respiratory Insufficiency vs. Respiratory Failure

The main difference between respiratory insufficiency and respiratory failure is  that respiratory insufficiency does not indicate that the respiratory system is completely unable to supply adequate oxygen to maintain metabolism and/or eliminate sufficient carbon dioxide to avoid respiratory failure.2 In contrast, respiratory failure is often defined as a respiratory condition requiring intervention such as mechanical ventilation or unplanned intubation, or use of naloxone.3

The likelihood for developing respiratory compromise may be influenced by a number of patient-specific or treatment-specific factors.

Discover below the common physiological pathways leading to respiratory compromise1 and which respiratory and monitoring solutions from Medtronic can help with the early identification of respiratory compromise.

Common physiological pathways leading to respiratory compromise1
  Hypoxic Respiratory Failure Hypercapnic Respiratory Failure Sleep Disordered Breathing Related Arousal Failure
Primary Issue Decreasing ability to oxygenate blood due to congestion (e.g., fluid, pus, etc.) in lung tissue (alveoli). Inadequate ventilation to clear carbon dioxide secondary to hypoventilation. Failure of patient to initiate hyperventilatory ‘arousal response’ following sleep apnea related hypoventilation. Failure of arousal response is often related to opioid/sedative administration.
Common Causes

Pneumonia

Pulmonary edema

Pulmonary embolism

Atelectasis

Pulmonary Fibrosis

Central hypoventilation

Asthma

COPD

Neuromuscular disorders

Chest wall disorders

Obstructive sleep apnea

Central sleep apnea

Cheyne-Stokes respiration

Precipitating Vital Signs

↑ Respiratory rate

↑ Minute ventilation

↓ Blood CO2

SpO2 is maintained until precipitous drop at respiratory failure

Normal or ↓ respiratory rate

↑ Blood CO2

Lagging drop in SpO2

Due to plateau of oxyhemoglobin dissociation curve, SpO2 is maintained above 90% through a significant rise in CO. Further masked by use of supplemental oxygen

Sawtooth pattern of of drops and increases in RR and MV

Results in reciprocal sawtooth rises and falls in blood oxygen and CO2

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Risk Factors for Respiratory Compromise

Multiple clinical studies have identified independent risk factors for respiratory compromise. Applicable risk factors may be altered by patient population or endpoint being investigated (e.g. respiratory failure, unplanned intubation, etc).

Risk factors for respiratory compromise

Risk factors for respiratory compromise
Study Outcome Risk Factor Odds Ratio 95% CI P Value
Alvarez 20154 Postoperative Respiratory Failure Age 1.018 1.016 to 1.019 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Male 1.255 1.211 to 1.299 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Inpatient Status 10.864 9.616 to 12.232 < 0.001
Alvarez 20154 Postoperative Respiratory Failure General Anesthesia 2.773 2.516 to 3.057 < 0.001
Alvarez 20154 Postoperative Respiratory Failure BMI 0.992 0.989 to 0.0994 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Smoking 1.297 1.244 to 1.353 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Dyspnea (moderate) 1.375 1.31 to 1.443 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Male 1.255 1.211 to 1.299 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Independent functional status 0.641 0.525 to 0.783 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Ventilator 1.365 1.241 to 1.501 < 0.001
Alvarez 20154 Postoperative Respiratory Failure COPD 1.578 1.503 to 1.657 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Male 1.255 1.211 to 1.299 < 0.001
Alvarez 20154 Postoperative Respiratory Failure CHF 1.467 1.354 to 1.591 < 0.001
Alvarez 20154 Postoperative Respiratory Failure Emergent Case 2.034 1.95 to 2.122 < 0.001
Ramachandran 20113 Early Postoperative Intubation BMI < 18.5 kg/m2 1.5 1.3 to 1.9 <0.001
Ramachandran 20113 Early Postoperative Intubation
BMI ≥ 40 KG/m2 1.3 1.1. to 1.6 0.011
Ramachandran 20113 Early Postoperative Intubation
BMI < 18.5 KG/m2 1.5 1.3 to 1.9 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Alcohol use 1.4 1.1 to 1.8 0.004
Ramachandran 20113 Early Postoperative Intubation
Current Smoker 1.5 1.3 to 1.7 < 0.001
Ramachandran 20113 Early Postoperative Intubation
BMI < 18.5 KG/m2 1.5 1.3 to 1.9 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Dyspnea 1.6 1.4 to 1.8 < 0.001
Ramachandran 20113 Early Postoperative Intubation
BMI < 18.5 Kg/m2 1.5 1.3 to 1.9 < 0.001
Ramachandran 20113 Early Postoperative Intubation
COPD 1.6 1.4 to 1.8 < 0.001
Ramachandran 20113 Early Postoperative Intubation
BMI < 18.5 Kg/m2 1.5 1.3 to 1.9 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Diabetes, insulin tested 1.3 1.1 to 1.5 0.003
Ramachandran 20113 Early Postoperative Intubation
BMI < 18.5 Kg/m2 1.5 1.3 to 1.9 < 0.001
Ramachandran 20113 Early Postoperative Intubation
CHF 1.6 1.2 to 2.0 0.001
Ramachandran 20113 Early Postoperative Intubation
Liver Function 1.4 1.2 to 1.8 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Cancer 1.5 1.3 to 1.8 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Prolonged Hospitalization 1.3 1.2 to 1.5 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Weight loss 1.5 1.2 to 1.8 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Sepsis 1.5 1.3 to 1.8 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Hypertension 1.4 1.2 to 1.5 < 0.001
Ramachandran 20113 Early Postoperative Intubation
Very high-risk surgery 5.3 4.4 to 6.4 < 0.001

Weingarten 20155
Naloxone Use Cardiovascular disease 2.56 1.28 to 5.11 0.008
Weingarten 20155 Naloxone Use OSA 2.44 1.15 to 5.19 0.021
Weingarten 20155 Naloxone Use Neurologic disease 4.05 1.61 to 10.17 0.003
Weingarten 20155 Naloxone Use Anesthetic Duration 1.07 1.00 to 1.22 0.043
Weingarten 20155 Naloxone Use Use of long-acting opioids 2.48 1.05 to 5.88 0.039
Weingarten 20155 Naloxone Use Respiratory event in Pacua 5.11 2.32 to 11.27 <0.001
  • 1. Lynn, L.A., & Curry, J.P. Patterns of unexpected in-hospital deaths: a root cause analysis. Patient Saf Surg. 2011;5(1):3.

  • 2. Health Information Associates. 2010. Respiratory failure diagnosis coding. Accessed online at https://www.hiacode.com/wp-content/uploads/2017/10/Respiratory-Failure-%E2%80%93-Clinical-Indicators-Treatment-Coding-and-Sequencing.pdf.

  • 3. Ramachandran, S. K., Nafiu, O. O., Ghaferi, A., Tremper, K. K., Shanks, A., & Kheterpal, S. Independent predictors and outcomes of unanticipated early postoperative tracheal intubation after nonemergent, noncardiac surgery. Anesthesiology. 2011;115(1):44-53

  • 4. Alvarez, M. P., Samayoa-Mendez, A. X., Naglak, M. C., Yuschak, J. V., & Murayama, K. M. Risk Factors for Postoperative Unplanned Intubation: Analysis of a National Database. Am Surg. 2015;81(8):820-825.

  • 5. Weingarten, T. N., Herasevich, V., McGlinch, M. C., et al. Predictors of Delayed Postoperative Respiratory Depression Assessed from Naloxone Administration. Anesth Analg. 2015;121(2):422-429.

  • 6. Cacho, G., Perez-Calle, J. L., Barbado, A., Lledo, J. L., Ojea, R., & Fernandez-Rodriguez, C. M. Capnography is superior to pulse oximetry for the detection of respiratory depression during colonoscopy. Rev Esp Enferm Dig. 2010;102(2):86-89.

  • 7. Maddox, R. R., Oglesby, H., Williams, C. K., Fields, M., & Danello, S. (2008). Continuous Respiratory Monitoring and a "Smart" Infusion System Improve Safety of Patient-Controlled Analgesia in the Postoperative Period.

  • 8. Overdyk, F. J., Carter, R., Maddox, R. R., Callura, J., Herrin, A. E., & Henriquez, C. Continuous oximetry/capnometry monitoring reveals frequent desaturation and bradypnea during patient-controlled analgesia. Anesth Analg. 2007;105(2):412-418.