Topic 5-6 Discussion

Q-1

What would be the difference between respiratory acidosis and alkalosis?

Respiratory acidosis is the acidosis that is caused by alveolar hypoventilation whereas respiratory alkalosis is the alkalosis that is caused by alveolar hyperventilation. During hypoventilation the lungs fail to expel CO2. Hypoventilation or decreased ventilation is the primary cause for excess CO2 in the body. Hyperventilation is primary cause for loss of excess CO2 from the body because during hyperventilation, lot of CO2 is expired through respiratory tract leading to decreased pCO2. Hyperventilation causes excess loss of CO2 from the body. Hyperventilation is primary cause for loss of excess CO2 from the body because during hyperventilation, lot of CO2 is expired through respiratory tract leading to decreased pCO2 (Batlle, Chin-Theodorou, & Tucker, 2017).

Provide an example of each arterial blood gas reading.

pH= 7.48, PaCO2= 28, HCO3= 22, PaO2= 85, Respiratory Alkalosis

pH= 7.33, PaCO2= 25, HCO3=12, PaO2= 89, Metabolic Acidosis

pH: 7.21, pCO2: 8.5, HCO3: 29, pO2: 7.2, Respiratory Acidosis

pH: 7.56, pCO2: 5.0, HCO3: 31, pO2: 10.7 Metabolic Alkalosis

 

Differentiate the initial treatment plan for respiratory acidosis and alkalosis using the ventilator as well as pharmacotherapeutic agents.

In mechanically ventilated patients who have respiratory alkalosis, the tidal volume and/or respiratory rate may need to be decreased. Inadequate sedation and pain control may contribute to respiratory alkalosis in patients breathing over the set ventilator rate. Therapeutic measures that may be lifesaving in severe hypercapnia and respiratory acidosis include endotracheal intubation with mechanical ventilation. Pharmacologic therapy can also be used to help improve ventilation. Bronchodilators like beta-agonists, anticholinergic drugs, and methylxanthines can be used in treating patients with obstructive airway diseases. Naloxone can be used in patients who overdose on opioid use (Banga & Khilnani, 2019).

COPD is commonly associated with HF in clinical practice, as in the patient. Both conditions incur significant morbidity and mortality. In COPD patients, HF should be treated according to usual HF guidelines as there is no evidence that HF should be treated differently in the presence of this respiratory disease. Although β-blocker therapy improves symptoms and survival among patients with chronic HF, it is frequently withheld in patients with COPD due to concerns of the diminution of the β2-agonist bronchodilator effect and the worsening of bronchospasm. Treatment with statins, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin-receptor blockers (ARBs) can reduce the morbidity and mortality of COPD patients. The use of diuretics is another important aspect that must be evaluated in these patients, given that high doses of loop diuretics can produce metabolic alkalosis, with the presence of hypoventilation as a compensatory mechanism, which in turn could worsen hypercapnia. Finally, patients with HF and concomitant COPD who require a regular long-acting inhaled bronchodilator, should start treatment with a long-acting antimuscarinic (Banga & Khilnani, 2019).

What environmental and nutritional interventions would you recommend for this patient?

Smoking cessation is essential to improving outcomes in patients with comorbid COPD. A number of studies and systematic reviews have demonstrated the benefits of exercise training in patients with either COPD. Patients with COPD, who have limited exercise capacity, can often achieve an increase in their activity level with pulmonary rehabilitation. Nutritional supplement therapy has been proved to be effective for maintaining and improving the muscle strength and exercise tolerance in poorly nourished COPD patients and are identified as a modifiable risk factor to chronic disease development and progression. Small frequent meals that are dense in nutrient content with sufficient calories that meet basal energy expenditure and induce weight gain, meals that require little preparation (e.g. liquid nutritional supplements, microwaveable), resting before meals, and taking daily dose of multivitamins are recommended (Rawal & Yadav, 2015).

 

Banga, A., & Khilnani, G. C. (2019). Post-hypercapnic alkalosis is associated with ventilator dependence and increased ICU stay. COPD, 6(6), 437–440. https://doi.org/10.3109/15412550903341448

Batlle, D., Chin-Theodorou, J., & Tucker, B. M. (2017). Metabolic Acidosis or Respiratory Alkalosis? Evaluation of Low Plasma Bicarbonate Using the Urine Anion Gap. American journal of kidney diseases: the official journal of the National Kidney Foundation, 70(3), 440–444. https://doi.org/10.1053/j.ajkd.2017.04.017

Rawal, G., & Yadav, S. (2015). Nutrition in chronic obstructive pulmonary disease: A review. Journal of translational internal medicine, 3(4), 151–154. https://doi.org/10.1515/jtim-2015-0021

Q-2

Patients should be assessed daily for readiness to wean off mechanical ventilation. Trials should be conducted with patient off sedation and on minimal ventilator support. For a spontaneous breathing trial to be considered successful, a patient should be able to breathe for at least 30 minutes without signs of hemodynamic derangement (respiratory rate <35, no significant elevation or drop in blood pressure, oxygen saturation >90%), and with the absence of signs of distress or anxiety. Other factors to consider include respiratory secretions burden, the presence of a strong cough, and ability to maintain adequate wakefulness. A successful trial is usually followed by a cuff leak test and removal of the endotracheal tube and discontinuation of mechanical ventilation. Cuff leak test is to ensure there is adequate gas leak around the endotracheal tube after the cuff is deflated. This ensures the airway is patent without significant laryngeal edema. Moveover, it is worth to mention that clinician’s judgment is an important consideration when considering extubation. Patients who should be considered high risk intubated patients, including those who repeatedly fail their SBT, patients with advanced COPD or CHF, hypercapnic patients, and those >65 years of age. An experienced clinician is often able to combine all the data together and see through an apparently failed weaning parameter (Eskandar & Apostolakos, 2017).

Every weaning that fails is associated with a higher morbidity for the patient. It is important to know and understand that at any given moment, there are more mechanically ventilated patients than should be. Finally, weaning from a mechanical ventilator should never be an emergency and preferably should be done during the day time. Discontinuing mechanical ventilation and removing the artificial airway as soon as possible reduces the risk of ventilator-induced lung injury, nosocomial pneumonia, airway trauma from the endotracheal tube, and unnecessary sedation, but premature ventilator-discontinuation or extubation can cause ventilatory muscle fatigue, gas exchange failure, and loss of airway protection (Boles & Welte, 2017).

Eskandar, N., & Apostolakos, M. J. (2007). Weaning from mechanical ventilation. Critical care clinics, 23(2), 263–x. https://doi.org/10.1016/j.ccc.2006.12.002

Boles, J. M., & Welte, T. (2007). Weaning from mechanical ventilation. The European respiratory journal, 29(5), 1033–1056. https://doi.org/10.1183/09031936.00010206

Q-3

Mrs. P. has been in the ICU for several days, has made gradual progression, and appears to be doing well with laboratory findings and arterial blood gases indicating normal readings. The enteral feeds were held overnight for anticipation of extubation. Describe the process for weaning the patient from the ventilator and discuss when it is appropriate to remove ventilator support as the patient has improved. What are the risks to monitor for as this process is implemented for the patient? Support your answer with two or three peer-reviewed resources.

The weaning process begins as the patient improves their condition and requires less ventilator support (Zein, Baratloo, Negida, & Safari, 2016). For example, someone requiring 50% Fio2 to maintain SpO2 saturation of 94-96% would not be eligible for a spontaneous weaning trial (Zein, Baratloo, Negida, & Safari, 2016). As we are able to come down on Fio2, respiratory rate, and peep to normal ranges ( approx 35% FiO2, RR 16-18, and Peep of 5) the patient would then have shown they only require minimal support and would be a candidate for a spontaneous weaning trial (Zein, Baratloo, Negida, & Safari, 2016).

Placing the patient on a weaning trial or pressure support for a time of at least 30 minutes but no longer than 120 minutes, would give us plenty of information on whether the patient is going to be successful or not (Zein, Baratloo, Negida, & Safari, 2016). Some things to look out for would be heart rate variability, breathing patterns, ability to follow commands, and vital sign stability (Zein, Baratloo, Negida, & Safari, 2016). If the patient's ability to maintain their heart rate, Spo2, a normal breathing pattern, and has an ability to follow commands, then the next step would be performing a rapid shallow breathing index calculation to give us the final determination of the patient's ability to successfully be extubated (Nabila et al., 2019).

The rapid shallow breathing index is calculated as Tidal Volume divided by Respiratory rate, and an overall goal would be less than 105 which would indicate an approximately 80% successful rate (Nabila et al., 2019). Adding the assessment, the ABG, the patient's response, toleration of the weaning trial, and finally, the RSBI all together can give the provider a great idea about how successful the extubation would be (Nabila et al., 2019).

Depending on the results, the patient could be extubated to BiPAP, nasal cannula, or room air, however, extubating to nasal cannula would be the safest, and we can always wean off the nasal cannula easily (Nabila et al., 2019).

Some risks of extubation include that the patient could fall back into respiratory distress or back into respiratory failure, these things can happen and although they are rare, still occur (Zein, Baratloo, Negida, & Safari, 2016). If these situations do happen, there is a possibility that the patient could be reintubated, or placed on non-invasive mechanical ventilation (Zein, Baratloo, Negida, & Safari, 2016).

References:

Nabila, I. L., Mohammad, F. M., Sahar, M., Abdelsalam. A, & M. Abdelwahab. (2019). Sonographic measurement of lung aeration versus rapid shallow breathing index as a predictor of successful weaning from mechanical ventilation. The Egyptian Journal of Bronchology, 13(4), 477–483. https://doi-org.lopes.idm.oclc.org/10.4103/ejb.ejb_7_19

Zein, H., Baratloo, A., Negida, A., & Safari, S. (2016). Ventilator Weaning and Spontaneous Breathing Trials; an Educational Review. Emergency, 4(2), 65–71.