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Brian X Weaver MS, RRT-NPS, RPFT Director of Respiratory Therapy ( Rt.) University Hospital / UMDNJ, Newark, N.J. Assistant Director CardioPulmonaryNeurodiagnostics Services On-Site Manager MMC Southern Campus 600 River Avenue | Lakewood | NJ 08701 [email protected] Regularly nebulized medication Non-conventional nebulized medication Respiratory meds in reverse Current Nebulizers Finally presented some fundamental mechanics review Albuterol β2-adrenergic agonists(receptor agonists) Smooth muscle relaxation. Beta-adrenergic receptors • Cyclic Adenosine MonoPhosphate (cAMP) Albuterol; Proventil, Ventolin, Levalbuterol; Xopenex, Terbutaline , Metaproterenol; Alupent Jill A. Ohar; James F. Donohue, Mono- and Combination Therapy of Long-acting Bronchodilators and Inhaled Corticosteroids in Advanced COPD, Respir Crit Care Med. 2010;31(3):321-333. Salmeterol: Serevent Diskus, Formoterol; Foradil, Symbicort Their long duration of action is due to the addition of a long, lipophilic side-chain that binds unbinds binds. unbinds Epinephrine vs Adrenalin John Able 1897 ---- Epinephrine extracts he prepared from the adrenal Iokichi Takamine 1901 ----- Adrenalin patented a purified adrenal extract, and the name trademarked by Park, Davis & Co in the U.S. Epinephrine became the generic name in the U.S. The British term for this chemical is Adrenaline http://www.britannica.com/biography/Jokichi-Takamine Dictionary of Scientific Biography | 2008 COPYRIGHT 2008 Charles Scribner's Sons Ipratropium exhibits Cyclic Guanosine MonoPhosphate (cGMP) decreased contractility of smooth muscle in the lung, Peanut allergy Atrovent inhalers used chlorofluorocarbon (CFC) as a propellant and contained soy lecithin in the propellant ……………………………..CFC inhalers were phased …………………………………………….. It has never been a contraindication when administered as a nebulized solution. http://www.drugs.com/pro/ipratropium.html The Ritedose Corporation Antibiotic . Used to treat bacterial Gram-negative Pseudomonas reduce mucus viscosity by splitting disulfide bonds Dornase alfa enzyme >> cleaves DNA hydrolyzes the DNA present in sputum/mucus and reduces viscosity Regularly nebulized medication Non-conventional nebulized medication Respiratory meds in reverse Current Nebulizers Finally presented some fundamental mechanics review Aerosolized drugs have several advantages over other drug formulations, • Quick onset of action • Low incidence of systemic adverse effects. • No pain to the patient • Convenient method of drug delivery. Disadvantage is the generally lower percentage of drug delivered to the site of action compared with other methods of administration; Mary Beth Shirk; Kevin R. Donahue; Jill Shirvani, Unlabeled Uses of Nebulized Medications, Am J Health Syst Pharm. 2006;63(18):1704-171 More research is needed to develop guidelines for their use since nebulization may provide benefits to many patients who otherwise cannot be treated or would be at risk of systemic adverse effects of the drugs. NEW JERSEY ADMINISTRATIVE CODE TITLE 13 LAW AND PUBLIC SAFETY CHAPTER 44F STATE BOARD OF RESPIRATORY CARE For the purposes of treating, managing, controlling and caring for patients with deficiencies and abnormalities of the cardiac and pulmonary system, a respiratory care practitioner may perform the following duties under the direction or supervision of a physician: 4) Administration of drugs and medications; Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others Prostacyclin Naturally occurring prostaglandin Potent vasodilator that increases intracellular cAMP Prostacyclin synthase ( enzyme responsible for the formation of prostacyclin), Deficient in the pulmonary endothelium Three prostacyclin analogs are FDA-approved for the treatment of PAH: Epoprostenol, Treprostinil and Iloprost. Tuder RM, Cool CD, Geraci MW et al. Prostacyclin synthase expression is decreased in lungs from patients with severe pulmonary hypertension. Am. J. Respir. Crit. Care Med. 159(6), 1925–1932 (1999). Iloprost is a synthetic prostacyclin half-life of only 20–30 min, it requires 6–9 inhalation sessions throughout the day specially approved inhalation system. Ventavis®, package insert. Actelion Pharmaceuticals US Inc., CA, USA. Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others opioids. One class of drugs that is frequently used in a nebulized form is the opioids. The mechanism of action of nebulized opioids is uncertain, Dyspnea end-stage can typically be done at home, which can provide additional psychological comfort to the patient. Foral PA, Malesker MA, Huerta G et al. Nebulized opioids use in COPD. Chest. 2004; 125:691–4 The most common nebulized opioids: Morphine Hydromorphone Generic Name: hydromorphone (oral) (HYE droe MOR fone) Brand Name: Dilaudid, Dilaudid-5, Exalgo Hydromorphone is much more soluble in water than morphine ---deliver the drug in a smaller volume of water. Fentanyl Fentanyl is approximately 80 to 100 times more potent than morphine and roughly 40 to 50 times more potent than pharmaceutical grade (100% pure) heroin. Limited research has also investigated nebulized-opioid use in the management of stable chronic obstructive pulmonary disease (COPD) and other respiratory diseases, but the results are conflicting. Foral PA, Malesker MA, Huerta G et al. Nebulized opioids use in COPD. Chest. 2004; 125:691–4. Farncombe M, Chater S. Clinical application of nebulized opioids for treatment of dyspnoea in patients with malignant disease. Support Care Cancer. 1994; 2:184–7. patients reported a decrease in shortness of breath, greater feelings of relaxation, and more exercise tolerance. They also reported no significant adverse effects. 63% of all patients and in 81% of patients who received more than three doses. Farncombe M, Chater S, Gillin A. The use of nebulized opioids for breathlessness: a chart review. Palliat Med. 1994; 8:306–12 Non-regularly nebulized Prostacyclin medication Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others Lidocaine is a common local anesthetic frequently nebulized during bronchoscopy procedures Lidocaine toxicity is a serious concern, and concentrations of serum lidocaine over 5 mg/L can lead to lightheadedness, tremors, hallucinations, and cardiac arrest. Wu FL, Razzaghi A, Souney PF. Seizure after lidocaine for bronchoscopy: case report and review of the use of lidocaine in airway anesthesia. Pharmacotherapy. 1993; 13:72–8. Langmack EL, Martin RJ, Pak J et al. Serum lidocaine concentrations in asthmatics undergoing research bronchoscopy. Chest. 2000; 117:1055–60. Lidocaine treatment is to manage bronchial hyperactivity. Studies examined the use of nebulized lidocaine in managing cough and asthma symptoms. Cough could be reduced with inhaled lidocaine acting locally in the tracheobronchial airways. Hansson L, Midgren B, Karlsson JA. Effects of inhaled lignocaine and adrenaline on capsaicin-induced cough in humans. Thorax. 1994; 49:1166–8. Study, evaluated nebulized lidocaine in the management of asthma. 50 Patients were given 100 mg of 4% lidocaine or placebo four times daily. Asthma severity indicators such as FEV1, symptoms, bronchodilator use, blood eosinophil counts, and nighttime awakenings showed improvement in the lidocaine-treated group by the end of the treatment period. nine of the patients in the lidocaine group had to stop treatment due to worsening asthma symptoms, Hunt LW, Frigas E, Butterfield JH et al. Treatment of asthma with nebulized lidocaine: a randomized, placebo controlled study. J Allergy Clin Immunol. 2004; 113:853–9. Non-regularly nebulized medication Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others Currently, the most widely accepted treatments for asthma include ß2-adrenergic agonists and corticosteroids. The search for treatment alternatives led to nebulized magnesium sulfate. The Action; it is associated with cellular homeostasis and frequently acts as a cofactor in enzymatic reactions. It has also been suggested that magnesium acts as a smooth muscle relaxant by interfering with calcium uptake. Mahajan P, Haritos D, Rosenberg N et al. Comparison of nebulized magnesium sulfate plus albuterol to nebulized albuterol plus saline in children with acute exacerbations of mild to moderate asthma. J Emerg Med. 2004; 27:21–5. A randomized, double-blind, controlled clinical study compared nebulized magnesium sulfate with nebulized albuterol in 33 patients with asthma (ages 12–60 years). The Fischl index score showed both groups improved by a significant amount (p < 0.05), and the improvements were similar between the two groups. Mangat HS, D’Souza GA, Jacob MS. Nebulized magnesium sulphate versus nebulized salbutamol in acute bronchial asthma, a clinical trial. Eur Respir J. 1998; 12:341–4. A different study examined magnesium sulfate as a vehicle for nebulized albuterol in treating acute asthma. 35 Random asthma patients received a one-time dose 2.5 mg of albuterol in 3 mL of 0.9% sodium chloride or 3 mL of isotonic magnesium sulfate. The magnesium group demonstrated significant improvements in PEF (61%) compared with the control (31%) group (p < 0.05). the PEF value was 48 L/min greater for the magnesium group. None of the test subjects reported any adverse events during treatment. Nannini LJ, Pendino JC, Corna RA et al. Magnesium sulfate as a vehicle for nebulized salbutamol in acute asthma. Am J Med. 2000; 108:193– 7. Non-regularly nebulized medication Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others Amphotericin B Antifungal drug often used intravenously for systemic fungal infections . It is the only effective treatment for some fungal infections The toxicity of antifungals when used to treat a systemic infection is also a concern. Investigation into alternative methods of treating these infections is ongoing Behre GF, Lenz K, Schilling E et al. Aerosol amphotericin B inhalations for prevention of invasive pulmonary aspergillosis in neutropenic cancer patients. Ann Hematol. 1995; 71:287–91. One study prospectively examined rates of fungal infections in patients receiving lung, heart, or heart–lung transplants. Then 126 patients received 5 mg of nebulized amphotericin B three times daily, increased to 20 mg three times daily within five days after surgery. The rate of fungal infection was compared with 101 patients who were transplanted without amphotericin B prophylaxis. Both groups of patients received the same immunosuppressive therapy after the transplant. The study found a significant decrease in the rate of fungal infections in patients receiving nebulized amphotericin B at 3 and 12 months Reichenspurner H, Gamberg P, Nitschke M et al. Significant reduction in the number of fungal infections after lung-, heartlung, and heart transplantation using aerosolized amphotericin B prophylaxis. Transplant Proc. 1997; 26:627–8 Results from multiple studies demonstrated that nebulized amphotericin B will not protect against invasive fungal infections in cases where the patient had a previous fungal infection during chemotherapy. the optimal time to begin prophylaxis treatment is during chemotherapy, before transplantation. Ideally, this would minimize the number of transplant candidates with preexisting infections. Monforte V, Roman A, Gavalda J et al. Nebulized amphotericin B prophylaxis for Aspergillus infection in lung transplantation: study of risk factors. J Heart Lung Transplant. 2001; 20:1274–81. Hertenstein B, Kern W, Schmeiser T et al. Low incidence of invasive fungal infections after bone-marrow transplantation in patients receiving amphotericin B inhalations during neutropenia. Ann Hematol. 1994; 68:21–6. Non-regularly nebulized medication Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others FDA non-labeled nebulization reported in the literature. Amikacin Antibiotic -hospital-acquired infections with MDR Gram Neg bacteria ( Kidney) Carbenicillin Antibiotic belonging to the subgroup of the Penicillins - Tx UTI ( Kidney) Ceftazidime – Antibiotic -It is a third-generation Cephalosporin - activity against both Gram-positive and Gramnegative bacteria ( few) Gentamicin – Antibiotic - wide range of bacterial infections, mostly Gram-negative bacteria but some Grampositive ( inner ear –Kindney) Has been reported in the cystic fibrosis population . Palmer LB, Smaldone GC, Simon SR et al. Aerosolized antibiotics in mechanically ventilated patients: delivery and response. Crit Care Med. 1998; 26:31– 9. Sermet-Gaudelus I, Marquette CH, Wallet F et al. Nebulized antibiotics in cystic fibrosis. Paediatr Drugs. 2002; 4:455–67. Stead RJ, Hodson ME, Batten JC. Inhaled ceftazidime compared with gentamicin and carbenicillin in older patients with cystic fibrosis infected with Pseudomonas aeruginosa. Br J Dis Chest. 1987; 81:272–9. Antibiotic effective against most Gram negative bacilli Colistin is an old drug not used much because of its nephrotoxicity It remains one of the last resorts for treating multidrug-resistant (MDR) P Aeruginosa , Klebsiella pneumoniae, and Acinetobacter and Multidrug resistant Enterobacteriaceae. Falagas ME, Grammatikos AP, Michalopoulos A (October 2008). "Potential of old-generation antibiotics to address current need for new antibiotics“. Expert review of anti-infective therapy 6 (5): 593–600. doi:10.1586/14787210.6.5.593. PMID 18847400. Non-regularly nebulized medication Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others Heparin Early trials with heparin for the prevention of exercise- induced asthma have been positive Heparin has also been studied to reverse the viscosity of sputum in patients with cystic fibrosis Garrigo J, Danta I, Ahmed T. Time course of the protective effect of inhaled heparin on exercise-induced asthma. Am J Respir Crit Care Med. 1996; 153:1702– 7. Ahmed T, Garrigo J, Danta I. Preventing bronchoconstriction in exercise-induced asthma with inhaled heparin. N Engl J Med. 1993; 329:90–5. Polosa R, Magri S, Vancheri C et al. Time course of changes in adenosine 5'-monophosphate airway responsiveness with inhaled heparin in allergic asthma. J Allergy Clin Immunol. 1997; 99:338–44. Ledson M, Gallagher M, Hart CA et al. Nebulized heparin in Burkholderia cepacia colonized adult cystic fibrosis patients. Eur Respir J. 2001; 17:36– 8. Non-regularly nebulized medication Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others powdered via nebulizer 2007 as effective, but not better than injected Cost prohibitive Exubera, by Pfizer in 2006 poor sales led Pfizer to withdraw it in 2007.[3] Afrezza, developed by Mannkind, approved by the FDA in 2014. IMPORTANT SAFETY INFORMATION FOR AFREZZA® (INSULIN HUMAN) INHALATION POWDER WARNING: RISK OF SUDDEN LUNG PROBLEMS (BRONCHOSPASM) IN PATIENTS WITH LONGTERM (CHRONIC) LUNG DISEASE Sudden lung problems (acute bronchospasm) have been seen in patients with asthma and COPD (chronic obstructive pulmonary disease) using Afrezza®. Afrezza® is not to be used in patients with long-term lung disease such as asthma or COPD. Non-regularly nebulized medication Prostacyclin Opioids Lidocaine Magnesium Amphotericin B Antibiotic Heparin Insulin And others Protein involved in the breakdown of blood clots. Serine protease ; In the cells that line the blood vessels An enzyme responsible for clot breakdown. Is used to treat strokes, PE, MI and DVT’ Rivera-Bou WL, Cabanas JG, Villanueva SE (2008-11-20). "Thrombolytic Therapy". Medscape. Dwayne Scott F, Wardlaw JM, Murray V, Berge E, del Zoppo G, Sandercock P, Lindley RL, Cohen G (June 2012). "Recombinant tissue plasminogen activator for acute ischaemic stroke: an updated systematic review and meta-analysis". Lancet 379 (9834): 2364–72. doi:10.1016/S0140-6736(12)60738-7. PMC3386494. PMID22632907. Vancouver style error (help) DeMers G, Meurer WJ, Shih R, Rosenbaum S, Vilke GM (December 2012). "Tissue plasminogen activator and stroke: review of the literature for the clinician". J Emerg Med 43 (6): 1149–54. doi:10.1016/j.jemermed.2012.05.005. PMID22818644. Plastic bronchitis is a lymphatic flow disorder that causes severe respiratory issues. In children with plastic bronchitis, lymph fluid builds in the airways and forms rubbery or caulk like plugs (known as casts). These casts block the airways, making it difficult to breathe. http://www.chop.edu/conditions-diseases/plastic-bronchitis The patient was extubated on hospital day 12 and was maintained on therapy with albuterol, N-acetylcysteine, budesonide, deoxyribonuclease (DNase) by nebulization, and oral sildenafil. Despite such therapy, other two episodes of respiratory deterioration occurred over the following 10 days, each requiring bronchoscopic removal of casts from the bronchial tree. After the latest episode, treatment with aerosolized t-PA (Actilyse, Boehringer Ingelheim) was added to the previous therapy. A total of 5 ml of the drug diluted to 1 mg/ml of normal saline was delivered every 6 hours via a Pari TurboBoy S compressor with a Pari LC Sprint reusable nebulizer and a mask (Pari GmbH, Starnberg, Germany). Over the next few days, the child started expectorating thinner bronchial secretions and his condition improved gradually, with clearing of areas of atelectasis and no recurrence of respiratory symptoms. The patient was discharged home receiving budesonide (0,5 mg twice daily), DNase (1,25 mg twice daily) and t-PA (5 mg four times daily) by nebulization, oral sildenafil, and chest physiotherapy. Massimo Colaneri,1 Andrea Quarti,1 Marco Pozzi,1 Stefano Gasparini,2 Ines Carloni,3 and Fernando Maria de Benedictis, Management of plastic bronchitis with nebulized tissue plasminogen activator: another brick in the wall , Ital J Pediatr. 2014; 40: 18. Published online 2014 Feb 13. doi: 10.1186/18247288-40-18, PMCID: PMC3974171 Nicolas Santos – Born with Hypoplastic Left Heart Syndrome 9-25-2000 Norwood Procedure at age of 4 days Bilatteral, birerectional Glenn at age of 5 ½ months Ruptured aorta during the Glenn procedure- Aortic reconstruction performed Fontan Procedure performed at age 3 Mid 2005, developed constant, ongoing and progressively worsening cough June 5, 2006 – Hospitalized due to severe respiratory distress June 11, 2006 Cardiac/Respiratory arrest. Diagnosed with Plastic Bronchitis Late June 2006 – Subsequent Respiratory Arrests, Multiple Bronchoscopies to remove significant casts. Placed on ECMO for cardiac and respiratory support Nicolas Santos – Started on Nebulized tPA Picture of Nick’s first cast removed during Bronch tPA- 12 vials per day from June of 2006 to November of 2013. Nick in August of 2006- After overcoming ECMO, multi organ failure, dialyses 8 bronchoscopies. On a slow road to recovery. Left hospital on October 13, 2006. Because respiratory treatments and airway clearance therapy would last over 1 hours-4x per day, during the last year+ of his life, several of Nick’s nebulized meds were replaced with inhalers. This was done strictly for quality of life purposes tPA broke down the vicious casts to loosely formed plugs that Nick was able to cough up or would be suctioned out. It was not unusual for Nick to soak 2 shirts per night front and back with the frothy secretions that would come from his trach. Nebulized Bicarbonate 1. The bronchial secretions acidity imparts stickiness 2. Aerosol use of bicarbonate for lung and bronchial adenocarcinoma. 3. Dr. Lewis Nelson, a specialist in emergency medicine says, “Nebulized sodium bicarbonate has been shown to provide symptomatic relief in patients exposed to chlorine, and it is probably useful with all irritant gases that liberate acid. Nebulized Peroxide Hydrogen peroxide has been used for decades to conquer viral infections Dr. Shallenberger testimony: I have treated hundreds of cases of colds, flus, sinusitis, and bronchitis all with the same great results. “not only is the hydrogen peroxide being disseminated into the entire body through the lungs, it is also going directly to the areas of the body that are most affected by viruses – the sinuses, throat, bronchial tract, and lungs.” Nebulized Iodine 1. Nebulization with iodine offers an extremely strong therapy which can clear the lungs quite rapidly of infections 2. When it comes to using iodine in a nebulizer special caution is needed. The choice of iodine is important because putting in potassium, which is found in Lugol’s, is dangerous. Potassium chloride, another salt of potassium, is used for lethal injection so I recommend only Nascent Iodine.. Nebulized Glutathione Glutathione :. One role is to enable the liver to remove toxins, medications and other substances from the body. 2. The glutathione level of the epithelial lining fluid is decreased in severe inflammatory lung diseases including in cases with Cystic fibrosis. 3. In a case of a 95-year-old man with an acute respiratory crisis secondary to emphysema and apparent bronchial infection treatment with nebulized glutathione led to a rapid resolution of the crisis, as well as a marked improvement in the chronic course of the disease. This treatment has been used since for a number of patients with emphysema. The safety and bioavailability of this method of delivery have been established in human studies. 1. Regularly nebulized medication Non-regularly nebulized medication Respiratory meds in reverse Current Nebulizers Finally presented some fundamental mechanics review When taken by mouth , acetylcysteine is used to prevent liver damage from Acetaminophen overdose. This drug may also be taken by mouth to prevent Kidney damage due to dyes from certain X-ray procedures (such as CT Scan). http://www.webmd.com/drugs/2/drug-63406/mucomyst/details Ophthalmic is used in the eye to treat bacterial infections of the eye. Tobramycin works by killing bacteria. Generic Name: albuterol inhalation (all-Bet-ter-all) Brand Names: I ordered it-Just do it, Patient wants it, their ear hurts, their foot hurts, just shut them up, I don’t know what else to do. For the treatment of just about anything that there is no particular treatment for. Including squeaky draws and cleaning truck parts. Medical Training instructions for idiots.com Regularly nebulized medication Non-regularly nebulized medication Respiratory meds in reverse Nebulizers Finally presented some fundamental mechanics review They are being developed in cooperation with pharmaceutical companies to deliver expensive formulations with which precise dosing is needed. Some drug solutions are only approved for delivery with specific nebulizers Respirgard II for aerosolized Pentamidine The Respirgard II is fitted with one-way valves and filters to minimize gross contamination of the environment. The Circulaire nebulizer reduces waste from a constant-output nebulizer by attachment of a storage bag with a one-way valve in the mouthpiece connector The AeroEclipse nebulizer has a breath-actuated valve that triggers aerosol generation only during inhalation, eliminating the need for a storage bag or reservoir. Rau, JL, Ari, A, Restrepo, RD. Performance comparison of nebulizer designs: constant-output, breathenhanced, and dosimetric. Respir Care 2004; 49:174. Ultrasonic nebulizers energy to high-frequency ultrasonic waves with a frequency of 1.63 megahertz. A piezoelectric element in the transducer vibrates at the same frequency as the applied wave. . Small volume ultrasonic nebulizers are commercially available for delivery of inhaled bronchodilators; large volume ultrasonic nebulizers are used for sputum induction. Vibrating mesh nebulizers — Several manufacturers have developed aerosol devices that use a vibrating mesh or plate It will generate aerosols with a high fine-particle fraction, which results in more efficient drug delivery compared to conventional nebulizers. Dhand, R. New frontiers in aerosol delivery during mechanical ventilation. Respir Care 2004; 49:666. The Aerogen® Solo Specifications The Aerogen® Solo is a compact, single patient use nebulizer for aerosol therapy, which can be used for continuous and/or intermittent nebulization. The Aerogen® Solo nebulizer produces a fine particle, low velocity aerosol optimized for targeted drug delivery. The iNeb nebulizer uses vibrating mesh technology with adaptive aerosol delivery (ADD). ADD monitors the patient's breathing pattern and injects the aerosol at the beginning of inhalation. This nebulizer is used specifically for the administration of Ventavis® (iloprost) Inhalation Solution (CoTherix, Inc) for the treatment of pulmonary arterial hypertension The Small-Particle Aerosol Generator (SPAG) was designed specifically to aerosolize Ribavirin. It consists of a nebulizer and drying chamber that reduce the MMAD to about 1.3 µm, which optimizes drug delivery to distal airspaces. The SPAG is used with a scavenging system to minimize contamination of the ambient environment. ; Regularly nebulized medication Properties of Nebulization Non-regularly nebulized medication Respiratory meds in reverse Nebulizers Gas density ; Albuterol with helium and oxygen (heliox). The flow to the nebulizer should be increased by 50 percent if it is powered with heliox Hess, DR, Acosta, FL, Ritz, RH, et al. The effect of heliox on nebulizer function using a bet agonist bronchodilator. Chest 1999; 115:184. Smaller particles tend to reach the lower respiratory tract with greater regularity but are more easily exhaled without reaching their targeted absorption site. Larger particles are more likely to have an effect on the upper respiratory tract but have a greater chance of not reaching the respiratory tract. A gas flow rate of 8 L/min has been recommended because that rate seems to balance the variables of nebulization time and particle size. Dolovich, MB, Ahrens, RC, Hess, DR, et al. Device selection and outcomes of aerosol therapy: evidence-based guidelines: American College of Chest Physicians/American College of Asthma, Allergy, and Immunology. Chest 2005; 127:335. Rau, JL. Design principles of liquid nebulization devices currently in use. Respir Care 2002; 47:1257. A jet flow of driving gas creates an area of low pressure above the medication reservoir, generating an aerosol. The baffle helps insure the formation of respirable particles, and prevents inhalation of oversized droplets of medication. Most nebulizers require a flow rate of 8 liters per minute for optimum performance webmd.com