This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.
Aspiration pneumonitis is known as an acute lung injury that results from inhalation of gastric content. Individuals with reduced consciousness, dysphasia, disorders of the upper gastrointestinal tract, pharyngeal anesthesia, mechanical disruption of glottis closure and other conditions related to elevated intragastric volume, have increased risk of developing aspiration pneumonitis (Hines & Marschall, 2008). The properties of increased gastric acid shared by these conditions, was initially described by Mendelson in 1946 and it is mostly referred to as Mendelson's syndrome. The syndrome predicts potential risk of aspiration pneumonitis based on the volume, content and acidity of the aspirate inhaled independent of infection. According to Mendelson's study, there is an increased risk for aspiration pneumonitis if the pH of the aspirate is less than 2.5, the volume of aspirate is greater than 0.3mL/kg (20-25mL in adults) and the aspirate contains particles (Marik, 2001).
Aspiration pneumonitis can progress very rapidly and within hours. However, symptoms are not apparent until hours after the aspiration. Symptoms of aspiration pneumonitis include wheezing, shortness of breath, coughing, hypoxia, cyanosis, hypotension, pulmonary edema and acute respiratory distress syndrome leading to death (Marik, 2001). As a result of serious complications that can ensue with this problem, individuals with increased risk of aspiration need to be carefully screened and prepared before undergoing any anesthestic management. The risk factors can be controlled by the assurance fasting period, 6-8 hours for solid food and 3-4 hours for clear liquid (Morgan, Mikhail & Murray, 2006). Further preventative technique, such as, nasogastric decompression, acid neutralization, acid suppression with non-particulate antacid and increased gastric peristalsis can be employed (Ng & Smith, 2001). Even though these patients are NPO preoperatively, they need to be treated as having full stomach (recent food intake) in order to ensure patient safety.
Individuals with aspiration pneumonitis manifesting one or more of the symptoms mentioned will require supplemental oxygen, ventilator support or both. Treatment is mainly supportive and may include the addition of positive end expiratory pressure, bronchoscopy for the removal of obstructing pieces and antibiotic therapy with a documented infection (Jean et al., 2008).
Patient's ability to undergo a surgical procedure with low anesthetic complications is established by preoperative assessment. Patient will be assessed for any airway abnormalities, history of injuries in the oral cavity. Visible structures of the airway will be evaluated and classified according to Mallampati classification system. Additional airway evaluation will include range of motion of head and neck, assessing interincisor distance, length and thickness of neck and thyromental distance. Breath sounds will be auscultated and the chest area will be assessed for any visual abnormalities (Stoelting & Miller, 2007). Baseline pulse-oximetry will be obtained and documented on room air.
Assessment of heart sounds and baseline vital signs will be performed. Enquire about the incidence of SOB with physical activities in order to determine any underlying cardiac and lung problems (Stoelting & Miller, 2007). Determination of patients BMI will be done to assess the risk of postoperative morbidity and associated anesthetic complications. Enquire if patient smokes and/ or drink, including his last drink and/or cigarette. Patient's current well being and psychological status will be assessed. Evaluation of family history of anesthesia complications, in order to, determines patient's risk of malignant hyperthermia and associated anesthetic complications. Head to toe physical assessment will be completed for any physical abnormalities and documented.
After the preoperative evaluation the anesthesia machine will be checked before connecting the patient to the machine. The anesthesia machine check includes; inspection of the low and high pressure system, examination of carbon dioxide absorbent color change, inspecting the breathing circuit for any loose connections, assessing proper functioning of the mechanical ventilator, performing a leak test, calibration of the oxygen analyzer, inspecting levels of vaporizer, checking the availability of back up battery and gas cylinders, assessment of proper functioning of the scavenging system and set alarm limits on the monitor (Stoelting & Miller, 2007). Some of the medications that will be made available in the cart include lidocaine, propofol, fentanyl, midazolam, glycopyrrolate, succinylcholine, rocuronium, neostigmine, ephedrine, antiemetics, H2-receptor blocker, opioid and benzodiazepine antagonist. Equipments to be ensured to be in the cart are laryngoscope, different size blades, stylets, different size tracheal tubes, oral/nasal airway, properly working suction and appropriate size face mask.
Assessment of patient's allergies will be evaluated and documented. To review drug interactions, all medications including over the counter drugs being taken by patient will be evaluated. Evaluations of these medications will facilitate the management of potential complications intraoperatively and postoperative phase. Enquiry of last oral intake will be evaluated to determine NPO status and possible aspiration risk. Preoperative assessment allows for the recognition of patients with increased risk aspiration pneumonitis. The patient identified to have increased risk for aspiration will be pre treated with bicitra for acid neutralization, metoproclopromide as a prokinetic and famotidine as a non-particulate antacid as preventative measures (Ng & Smith, 2001). The combination of these agents prevents aspiration during intubation.
After the preoperative assessment anesthetic choice is made in collaboration with the patient and the surgeon. The final decision ultimately rest on patient's safety in relation to the type of surgery. Regional anesthesia with minimal sedation is considered one the safe anesthetic technique in patients with increased risk of aspiration (Morgan, Mikhail & Murray, 2006). General anesthesia with endotracheal intubation can be used if regional anesthesia is contraindicated. Patients undergoing general anesthesia are pre treated with bicitra, metoproclopromide and famotidine.
After the pre treatment, patients who are known to be easy intubation will undergo rapid sequence induction (RSI) or Sellick maneuver intubation. The use of RSI is intended to allow rapid, safe airway management and protection while minimizing periods of hypoxia. The technique involves preoxygenation via bag-mask ventilation to establish the presence of a patent airway as well as to determine the ability to oxygenate. At this point, cricoid pressure is applied followed by the administration of an induction agent, propofol, which rapidly produces unconsciousness and apnea. Neuromuscular blocking agent such as succinnylcholine is immediately given after the propofol. Laryngoscopy and endotracheal intubation is performed. Cricoid pressure is released after the confirmation of endotracheal tube placement by auscultating bilateral breath sounds, ETCO2 and bilateral chest expansion. Patient is then ventilated with additional paralytic agent and sedation as needed (Batra & Mathew, 2005).
Furthermore, secured airway can be achieved via awake- intubation technique in patients with known difficult airway. This can be a frightening situation for the patient, it is therefore imperative to thoroughly prepare the patient and carefully explained the procedure. Patient can be pre-medicated with antianxiolytic decrease anxiety. Awake- intubation is usually accomplished by the "blind" nasal route, fiberoptic bronchoscopy, or direct visualization, often with the aid of Magill forceps (Batra & Mathew, 2005).
After securing the airway, patient will be connected to the ventilator, attached to EKG monitor, pulse-oximetry and capnography. The number of hours fasted will be calculated and patient will be evaluated for episodes of nausea, vomiting or diarrhea. Intraoperative fluid requirement and administration will be estimated using the 4:2:1 rule (Stoelting & Miller, 2007). Half of the calculated fluid requirement will be replaced with isotonic solution during the first hour of the surgery. Half of the rest of the fluid will be given during the second hour of surgery. During this time, if there is a blood loss, the replacement for the blood loss will be added. Each 1ml of blood loss will be replaced with 3ml of crystalloid isotonic solution (Stoelting & Miller, 2007). The rest of the fluid with any additional blood loss will be replaced during the third hour. If the surgery lasts less than three hours, the fluid will be completed during postoperative period. Volatile anesthetic will be used and nitrous oxide will be used with caution or avoided with patients undergoing abdominal surgery. Patient will be vigilantly monitored for any signs of aspiration during the anesthetic care.
Emergence from anesthesia can cause increased risk of aspiration (Morgan, Mikhail & Murray, 2006). Therefore, "full stomach" patients need to be fully awake, full return of airway reflexes and free of nausea/vomiting before extubation. These patients need to be aggressively treated for postoperative nausea and vomiting (PONV). Treatment of PONV will decrease the risk of aspiration, decrease patients anxiety as well as decrease length of hospital stay (Ng & Smith, 2001). Some of the agents used for PONV treatment include metroclopromide, ondansetron, dexamethasone and scopolamine patch. In addition to the treatment of PONV, administration of analgesic for postoperative pain improves patients' outcome. Ketorolac, morphine and fentanyl are some analgesic that can be use to control pain. Patient can discharge be discharged after the assurance of adequate oxygenation and ventilation, adequate pain control and free of nausea and vomiting.