Pulmonary Disease Lecture 7 Fall 2024 PDF

10/9/24 Pulmonary Disease C LINIC AL NU TRITIO N ASSESSMENT AND INTERV ENTIO N LEC TU RE 7: FAL L 2024 1 2 1 ...

10/9/24 Pulmonary Disease C LINIC AL NU TRITIO N ASSESSMENT AND INTERV ENTIO N LEC TU RE 7: FAL L 2024 1 2 1  10/9/24 Pulmonary Failure v Insufficient ventilation and/or inadequate oxygenation of arterial blood with or without elimination of CO2 o May be acute or chronic v Acute respiratory failure o Acute lung injury (ALI), e.g. smoke inhalation o Pneumonia o Acute respiratory distress syndrome (ARDS), associated with systemic inflammation in the critically ill o rapid onset of dyspnea (SOB) and severe deficits in gas exchanges v Chronic respiratory failure o Chronic obstructive pulmonary disease (COPD) o Lung cancer o airflow limitations (not fully reversible) 3 3 Acute Respiratory Distress Syndrome (ARDS) v Patients with ARDS present with acute onset of SOB, tachypnea, hypoxemia, which is refractory to oxygen supplementation o Clinical conditions commonly associated with ARDS: sepsis, pneumonia, aspiration, inhalation injury, near drowning, trauma, etc v Principles of ARDS management: o Treatment of underlying cause, such as sepsis, aspiration or bacterial pneumonia o Mechanical ventilatory support o Hemodynamic stability o Prevention of complications, ie pressure injuries, DVT o Provision of nutrition support for prevention of cumulative caloric deficits, loss of lean body mass, malnutrition and deterioration of respiratory muscle strength § Underlying clinical events such as sepsis or trauma that lead to the development of ARDS also result in hypermetabolic state § Malnutrition common in patients who require mechanical ventilation § Important not to overfeed à delayed weaning from mechanical vent 4 2  10/9/24 Acute Respiratory Distress Syndrome (ARDS) Complications from Overfeeding and Underfeeding in ARDS Underfeeding Overfeeding o Nosocomial (ie hospital acquired) o Nosocomial infections infections o Hypercapnia o Immunosuppression o Immunosuppression o Depressed respiratory muscle strength o Failure in weaning from mechanical o Failure in weaning from mechanical ventilator ventilator o Stress hyperglycemia o Low ventilatory drive o Poor wound healing o Electrolyte imbalance o Azotemia 5 COPD v Chronic Obstructive Pulmonary Disease o Chronic bronchitis § inflammation of bronchi § excess mucous production § chronic cough § difficulty breathing § may à cardiac enlargement with failure o Emphysema § abnormal, permanent enlargement and destruction of alveoli § chronic mild cough § nutritional depletion greater in these patients o These conditions may coexist in varying degrees § Those with primary emphysema have more dyspnea, cachexia § Those with bronchitis: hypoxia, hypercapnia (increased carbon dioxide), more complications such as pulmonary hypertension, right heart failure 6 3  10/9/24 7 COPD v Third most common cause of death in the world v Causes o Smoking (cigarettes, pipes, cigars, …) o Environmental: second-hand smoke, air pollution, chemical fumes, dust o Rarely – genetic X environment § Alpha-1 antitrypsin deficiency + exposure to smoke or other lung irritants v Airflow obstruction in COPD is irreversible v Patients with COPD are more susceptible to nutritional depletion o Dyspnea is significantly correlated with energy intake o Increased work of breathing increases energy requirement v Frequent acute exacerbations in COPD patients o Increases the severity of chronic inflammation o Malnourished individuals more likely to have exacerbations and shorter survival time than those who are well-nourished 8 4  10/9/24 COPD v Malnutrition common with COPD: 30-60% prevalence rate o Inadequate oral intake § Low appetite § Increased breathlessness while eating § Difficulty shopping and preparing meals § Dry mouth § Altered taste perceptions § Early satiety § Fatigue o Increased metabolic rate o Extra energy required for work of breathing § Normal breathing expends 36-72kcal/d, increases 10-fold with COPD o Frequent and recurrent respiratory infections, +fever vMalnutrition more likely with ventilated patients o May make it difficult to wean off vent 9 COPD v Effects of malnutrition on pulmonary physiology o Muscle compromise § diaphragm, intercostal muscles, accessory muscles o Impaired immunocompetence § decreased IgA, cell medicated immunity, epithelial integrity, T/B cell dysfunction o Surfactant deficit § surfactant lowers surface tension, prevents atelectasis v Individuals with COPD and low body weight o Impaired pulmonary status o Lower exercise capacity o Higher mortality than those adequately nourished v May lead to cor pulmonale o Increased blood pressure à enlargement of right ventricle of heart and right sided heart failure à can result in fluid retention § “Weight gain” from fluids can mask weight loss, camouflage wasting 10 5  10/9/24 Arterial Blood Gas Analysis v pH/PCO2/PO2/HCO3/O2 sat v Evaluation of ABGs determines pH, oxygen content, and carbon dioxide content of blood, and can be used to measure pulmonary function v PCO2 o Partial pressure of CO2 o Measures how much CO2 is dissolved in the blood and how well it is able to move out of the blood into airspaces of lung o Direct indicator of pulmonary function and effectiveness of mechanical ventilation o Normal values: 35-45 mm Hg 11 11 Arterial Blood Gas Analysis v HCO3 (chemical buffer) o Reflection of renal regulation of acid-base balance o Reacts more slowly than pulmonary regulation of acid base balance via PCO2 exchange o Normal values: 21-28 mEq/L v PO2 o Indirect measure of O2 content of the arterial blood and how well O2 is able to move from the lungs into the blood o Normal values: 80-100 mmHg v O2 saturation o Reflects the percentage of hemoglobin saturated with O2 o Normal Values: adult 95-100%, elderly 95% 12 12 6  10/9/24 Arterial Blood Gas Analysis o In respiratory disorders, pH and PaCO2 change in opposite directions o In metabolic disorders the pH and PaCO2 change in the same direction Acidosis Respiratory pH ↓ PaCO2 ↑ Acidosis Metabolic pH ↓ PaCO2 ↓ Alkalosis Respiratory pH ↑ PaCO2 ↓ Alkalosis Metabolic pH ↑ PaCO2 ↑ Disorder pH Primary problem Compensation Metabolic acidosis ↓ ↓ in HCO3- ↓ in PaCO2 Metabolic alkalosis ↑ ↑ in HCO3- ↑ in PaCO2 Respiratory acidosis ↓ ↑ in PaCO2 ↑ in [HCO3-] Respiratory alkalosis ↑ ↓ in PaCO2 ↓ in [HCO3-] 13 13 Etiology v Metabolic acidosis v Respiratory acidosis (CO2 retention) ◦ Diabetic ketoacidosis ◦ COPD ◦ Uremia ◦ Asthma ◦ Lactic acidosis ◦ OSA ◦ GI loss of HCO3 ◦ Neuromuscular impairment ◦ diarrhea, ileostomy ◦ Incorrect mechanical vent settings ◦ Renal loss of HCO3 v Respiratory alkalosis (CO2 loss) ◦ Renal tubular disease ◦ Hyperventilation v Metabolic alkalosis ◦ CNS stimulation ◦ GI loss of H+ ◦ Fear, pain, anxiety, head trauma, ◦ vomiting, gastric suction brain tumor, CVA, CNS infection ◦ Renal loss of H+ ◦ Incorrect mechanical vent settings ◦ loop, thiazide diuretics 14 14 7  10/9/24 Blood Gas Interpretation in COPD v Early disease: amount of oxygen in arterial blood is WNL v As disease progresses (middle stage): PO2 drops (< 60 mm Hg) hypoxemia* → hyperventilation → respiratory alkalosis v Later stages: Not enough energy to hyperventilate, CO2 builds up o Hypoxemia with Chronic Respiratory Acidosis § Lower pH § Increased PCO2 § Respiratory depression ↓ oxygen in and carbon dioxide out * deficiency of oxygen in arterial blood 15 15 Management of COPD v Assess and monitor disease o Manage exacerbations v Treatment o Pulmonary rehabilitation programs o Oxygen therapy o Medications § Bronchodilators § Glucocorticosteroids Ø Osteoporosis (long-term use) § Mucolytic agents § Antibiotics Ø When bacterial infection suspected cause of exacerbation 16 16 8  10/9/24 Management of Respiratory Failure v O2 supplementation (nasal) v Non invasive ventilation o Bilevel positive airway pressure (BiPap) o Continuous positive airway pressure (CPAP) v Invasive (mechanical) ventilation o Continuous mechanical ventilation o Intermittent mandatory ventilation 17 MNT v Goal: adequate intake to prevent loss of lean body mass (LBM) o Small frequent meals (5-6x/day) that are nutritionally dense o Consumption of main meal when energy level is at its highest § Typically in the morning; early in the day o Provision of adequate calories and protein § Determine individual needs § Protein: 1.2-1.5g/kg (possibly higher) Ø Requirements at higher end with malnutrition/muscle wasting § Calories: indirect calorimetry (gold standard); or 25-35kcals/kg Ø On vent: 25-30kcals/kg, or use predictive formula o Availability of foods that require less preparation, can be heated easily o Eating slowly and having period of rest before mealtimes o Use of oral supplements between meals to optimize intake o Limit fluids intake at mealtime; fluids between meals can help to increase ability to consume nutrient-dense foods at mealtimes 18 9  10/9/24 MNT v Enteral nutrition initiation may be indicated when oral intake is insufficient (for prolonged period) and patient has adequate GI function o Standard polymeric enteral formula (1 kcal/cc) o Maintain aspiration precautions § Monitor position of head § HOB minimum 30 degrees (45 degrees is preferable) v COPD patients are particularly vulnerable to re-feeding syndrome o Monitor closely; hallmark of re-feeding: ↓ levels of P, K and Mg o Typically occurs within 3 days of feeding o Other signs § Hyperglycemia and hyperinsulinemia § Interstitial fluid retention § Cardiac decompensation and arrest v Hypercaloric feeding may ↑ CO2 production à hypercapnia o DO NOT OVERFEED while weaning from mechanical vent 19 19 MNT v Additional considerations o Provide adequate fluids / hydration to help sputum consistency § Recommended fluid intake 35ml/kg for 18-60 years old § Recommended fluid intake 30ml/kg for >60 years old § Exception: patients with cor pulmonale and subsequent fluid retention may require sodium and fluid restriction o Vitamins and minerals § Individualize § Vitamin C supplement for smokers § Assess Ca/vitamin D adequacy, particularly with poor overall intake v Osteoporosis § Consider potential medication side effects o Consider factors that can be affecting intake § Individualize feeding strategies, interdisciplinary team § Difficulty preparing food because of fatigue § Lack of financial resources 20 10