Anaesthetic Management - Essay Example

Anaesthetic Management of a Patient with Chronic Obstructive Pulmonary Disease (COPD) COPD ranks fourth among the death causing diseases worldwide and was projected to be the third leading cause of death in 2020. (Murray and Lopez, 1997). The author further revealed that death rates trend continue on the rise due to COPD ailment increasing with age and normally starts from 45 years old. Clinical admissions data revealed that COPD was often associated with other ailments like abdominal tract aneurism and other heart ailments. Under this situation, needed surgery to correct the primary ailment becomes complicated especially in anaesthetic management. Patients with COPD ailments need professional anaesthetic management both in perioperative and postoperative situations due to the fact that anaesthetics directly affect the respiratory functions which may lead to morbidity. Based from this special consideration, it is of prime importance to know the effective anaesthetic management procedures of COPD patients to prevent morbidity, increase higher survival chance and ensure the well being of their health. Chronic Obstructive Pulmonary Disease is characterized by a progressive, partially reversible airflow limitation (Buist, 2007). According to the author, the chronic airflow limitation is depicted by two disease processes, chronic bronchitis which is a relentless coughing associated with sputum production and emphysema which on the other hand is described as progressive destruction of the lung parenchyma which leads to dyspnea especially on exertion. Further more, the author claimed that in most patients with COPD, this disease processes arise together. The author stressed that smoking is mainly the important risk factor in patients with COPD. The author claimed that Spirometry is essential in the diagnosis of COPD. In obstructive pattern like COPD, the FEV1 (the force expiratory volume in one second) is reduced to less than 70% of the predicted value in terms of your age, size and weight. The ratio between FEV1/FVC should be 0.7 or less, otherwise, the medical case is not COPD. The author emphasized that the FVC (Forced Vital Capacity) is the total amount of air that you breath out after maximum expiration,. 2 Pathophysiogical changes COPD causes major pathological related changes in the four different lung compartments namely central airways, the surrounding airway system as well as the pulmonary vasculature (Bowes, ca 2007). The mechanism starts when the lung vasculature is exposed with toxic gases and particles that may come from cigarette smoke (Bowes, ca 2007) or other occupational chemicals. (American Thorasic Society, ca 2007). The author further revealed that in COPD patient, the chronic inflammation is pronounced in the tracheal central airways, in the bronchi and in the larger bronchioles resulting to more epithelial goblet and squamous cells, the mucous secreting glands are enlarged, filial function is impaired and the formation of connective tissue and smooth muscles is increased. This in turn cause the production of elastases that cannot be work against by the antiproteases and so, lung destruction ensues. The small bronchi and bronchioles of the peripheral airways undergo similar process but the most distinct is the narrowing of the airway. The author further point to the fact that the destruction of the lung gas exchanging surfaces lead to well pronounced bronchi and alveoli of the lung parenchyma .The author further added that COPD patients also exhibit changes in the pulmonary vasculature. Slight thickening of the walls of the blood vessels is very common in mild disease condition and the thickening progresses as the disease advances. These all result to increase in vascular pressure thereby destroying the capillary bed of the lungs. Also, oxidative stress formed from the free radical emission of cigarette smoke may lead to apoptosis of exposed cells. These changes result to chronic and progressive thickening of the airway wall, alveolar attachments are lost and oversecretion of mucus and absence of the lung's elastic recoil innate property. The role of surgery and anaesthesia management Studies suggest that lobar surgery with the aim of reducing it may relieve symptoms in severe emphysema patients. This technique involves removing the enlarged emphysematous cells that normally lead to improvement of the lung tension and lung's mechanical performance related to distributing ventilation to functional tissues of the lungs (Bowes, ca 3 2007). It is a known fact that anaesthesia and method of induction is essential in surgery. According to Rutkowska et.al (2006), the method of anaesthesia induction should be adjusted according to planned surgery. The doctors emphasized that regional anaesthesia is safer and it offer lower side effect risks than general anesthesia. In major epigastric and thorasic surgery, general anaesthesia is combined usually with epidural block. The doctors remind that inhalation aenaesthethics cause brochial dilation while epidural anaesthesia promotes effective analgesic result without the need of opiods administration. Moreover, the need for increased duration of mechanical ventilation is minimized thereby lowering the likely incidence of pneumonia in postoperative situations. The doctors suggested that utmost care should be exercised in using epidural or subarachnoid analgesics so that extensive blockage of motor nerves of muscles responsible for active expiration including muscles in the abdomen can be minimized. The upper body region should be elevated during the surgical operation as it promotes spontaneous ventilation. The doctors added that extensive sympathetic blockage usually result to bronchospasms. They reported that high epidural anaesthesia using ropivacaine and bupivacaine usually minimize bronchospasms and only slightly reduce the FEV1. The authors revealed that "in cardiosurgical anaesthesia it is beneficial to give up extracorporeal circulation. It allows avoiding the effects of generalized inflammatory reactions on the diseased lungs" (The choice of anaesthesia, p.155). The doctors further said that contraindicated drugs cannot be clearly defined but it is of common knowledge that long term action drugs and those that are depressant in action to myocardium should be avoided specially in identified risk cases of right ventricular insufficiency. The anaesthesia administration can be done with intravenous agents and the most effective drug is propofol, according to the doctors. This drug minimizes the airway resistance and promotes inspiratory flow and at the same time decrease brochi reactivity. On the desired length of anaesthetic activity, the doctors claimed that anaesthetic effect with profonol can be 4 best maintained in the absence of emphysematous bullae with inhalation anaesthetics in combination with nitrous oxide. The combination result to bronchial dilation, better control and quicker elimination thereby promoting quick extubation. Inhalation anaesthetic preparations Anaesthetic effect can be achieved through the use of inhalation anaesthetic preparations. With inhalation anaesthetics, the desired effect can be maximized with the combination of nitrous oxide. The doctors revealed that in the early postoperative instances, inhalation anaesthetic effect from the combination on respiratory depression is negligible and quickly eliminated from the patient's system compared to intravenous route. The following are the choices for inhalatory anaesthetic preparations: 1. Halothane according to doctors substantially reduce the airways' resistance at reduced rates and does not the effect at rest. However, some other properties of halothane should be considered in deciding what anaesthetizing agent to use like its strong negative inotropic activity, severe ventricular arrhythmias and considerably lowering down of anaesthetic activity in only a short time. If the desired anaesthetic effect according to operation plan is short-acting, then halothane should be the choice. 2. Isoflurane is another anaesthetic preparation that is gaining popular use among anesthesiologists. According to doctors, Isoflurane and other newer agents have significantly reduced side effects. However, this chemical exhibit bronchial effects and may also cause moderate tachycardia. Branchospasms resulting from Isoflurane anaesthesia in a patient with hypersensitive airways is very common, according to the doctors. 3. Another anaesthetic agent is Desflurane. This agent, according to the doctors is nasal irritant and may cause cough, tachycardia or laryngospasm but other patients are not reactive to nasal irritant property of this preparation. 4. The other inhalation anaesthetic preparation is Sevoflurane. The doctors claimed that this nasal anaesthetic is an optimal inhalation anaesthesia for COPD patients due to its advantage 5 as haemodynamic stability enhancing effect on patients particularly those with cardiovascular diseases. 5. Remifentanyl owing to its desired pharmacokinetics is being considered by most neurologists as the best preparation for patients with risks of postoperative respiratory- related complications. It is fast acting with short half life and is rapidly broken down in tissues and blood by esterases which are non-specific. If Remifentanyl is used, even if the infusion time is long, the respiratory depression stops as quickly as in cases of short-term administration. The patient can recover within minutes after infusion pump disconnection, are better oriented, start spontaneous respiration with ease and more effective coughing can be observed. For anaesthesia needs prior to surgery, opiods with short term actions are often applied like fentanyl and derivatives. The doctors however cautioned that they cause dose- dependent depression of the central respiration, can result to muscle rigidity and can inhibit the cough reflex mechanism of the patient. The doctors adviced that great caution should be considered especially when administering them without endotracheal intubation. Moreover, the doctors adviced that those anaesthetics should not be used without combination with other inhalatory anaesthetics. Medical cases on anaesthetic management of diseases associated with COPD The first case involved the use of non-invasive positive pressure ventilation in combination with spinal anaesthesia for the purpose of inserting a dynamic hip screw to an obese patient with advanced COPD (Leech et.al, 2006). According to doctors, a 76 year old female patient with BMI 37kgm2 went to the hospital for fixation of fracture neck of femur with DHS. She had an advanced COPD, cor pulmonale, and pulmonary arterial hypertension. Her exercise tolerance, limited by breath shortness was 5-10 yards and she cannot lie flat for more than 10 minutes. The preoperative respiratory function test result was FEV1 0.7 and FEV1/FVC of 0.4. The doctors reported that "Echocardiography showed evidence of right heart failure and moderate pulmonary arterial hypertension. Electrocardiography showed right bundle branch block" (Case Report, 1st par.). The common anaesthetic approach to this patient 6 would be a general anaesthetic and need for intubation and ventilate invasively during and some periods at post operation. Prolonged endotracheal intubation may result to upper airway trauma, ventilator pneumonia and swallowing /speech related problems. Knowing these risks according to the doctors, spinal anaesthesia combined with NIPPV was decided as the best approach. Using this technique, they were able to produce satisfactory intraoperative and postoperative analgesia, the supine position was maintained through the duration of the operation and totally avoided the hazards of general anaesthesia and postoperative ventilation. By understanding the mechanism by which respiratory compromise and failure in an obese patient with COPD, the wisdom of using regional anaesthesia and NIPPV becomes obvious. The doctors reported that ventilation was made possible with the respiratory muscle able to pump against a load on it, in combination with an adequate central respiratory drive to maintain the pump. According to them, events as well as conditions which weaken the pump, increase work load and decrease in the central drive will increase the risk of ventilatory failure. NIPPV was proven as effective in the control of wide ranging conditions of ventilatory failures related to chest wall deformity, neuromuscular disorder and abnormal central respiratory drive. NIPPV has been popular over the years in the management of both acute exacerbations and in cases of chronic and stable COPD. Most COPD patients are prone to ventilatory problems brought by the failure of the above mentioned three factors. The contributing cause of failure is partly from worsening obstruction of the airflow leading to chest hyperinflation and the development of intrinsic PEEP. The author revealed that after operation, the risk of respiratory failure is greater due to opiates' effect and analgesics action resulting to weakening of the respiratory drive. In the case of obese patients, there is reduction in functional residual capacity (FRC) and expiratory reserve volume. The basal lung become over ventilated leading to mismatch in ventilation- perfusion ratio and hypoxaemia of the arteries. This situation is normally worsened by the compression atelactasis common during general anaesthesia wherein lung tissue in dependent a region is compressed by an increased abdominal and pleural pressure. Simultaneously 7 occurring is a cephalad shift of the diaphragm due to altered chest geometry as well as related changes in the diaphragm and a pooling of central blood in the abdomen. The doctors revealed that one study in a postoperative case, has identified a clear reduction of spirometric volumes proportionately with BMI as well as the need for oxygen as directly proportional to body weight. This put more risk on respiratory failure due to an increased need on a system that has already exhibiting reduced capacity. This is naturally occurring in COPD situation and act synergistically with obese condition towards respiratory failure. The NIPPV involved in this case was two-level pressure support ventilation referred as BiPAP. The principle behind is the fact that elevated inspiratory positive airway pressure helps ventilation while the lower counterpart increases extrinsic PEEP thereby balancing in return any intrinsic PEEP. By doing so, it aid under-ventilated lungs, increase tidal volume, reduce respiratory frequency and decreasing the effort for breathing. The improvement in ventilation therefore is directly proportional to the pressure applied. This is compared with continuous positive airway pressure which proved not to improve ventilatory conditions in short term and require much longer application to be effective. The doctors claimed that spinal and epidural anaesthetic introduction are beneficial to both obese with advanced COPD patients. Furthermore, they claimed that "compared with general anaesthesia, the maintenance of spontaneous breathing means there is less cephalad displacement of the diaphragm and less risk of atelectasis () closing capacity and FRC are less affected and pulmonary gas exchange is better maintained" (Discussion, 7th par.). The doctors claimed that ideally, solely nerve block anaesthesia could have served the purpose and avoiding any compromise in breathing but the patient's obese condition proved that this is not technically possible. The doctors revealed that the other benefits of spinal anaesthesia include postoperative analgesia without the risk of respiratory depression and avoidance of the need for strong stimulation of intubation and the risk of constriction of the bronchial opening on extubation. The disadvantage of solely regional anaesthesia is that many awake obese and COPD patients may not endure remaining in supine position needed for surgery. 8 This is the rationale of combining spinal anaesthesia with NIPPV. In conclusion, the doctors recommend the use of the technique with patients with COPD that require postoperative ventilation and who cannot lie flat for extended time during the period of operation. The second case involve a 74 year old man with gastric cancer complicated with abdominal tract aneurysm coupled with COPD (Usukura et. al, 2008). A two stage surgery was planned which require repair of abdominal aortic aneurysm and gastrectomy. It is essential to maintain spontaneous breathing during the surgical operation under epidural and light general anaesthesia. For the first surgery, two epidural catheters were placed at T1-2 and T7-8 on the day prior to surgery. After establishing epidural anaesthesia, general anaesthesia was introduced and maintained with midazolam, fentanyl and sevoflurane and without muscle relaxant with BIS monitoring. A 0.375% Ropivacaine solution was infused through an epidural catheter and spontaneous breathing was kept along with the operation. The surgery according to the authors lasted for almost five hours and satisfactory recovery of the patient was noted. The second operation was done forty days after the first surgery. Anaesthetic management was almost similar as the first one except for the use of dexmedetomizine in place of sevoflurane. In both surgeries, sufficient analgesia was ensured with epidural anaesthesia and the surgeons were satisfied noting the satisfactory muscle relaxation. Moreover, with the procedure, postoperatively, no respiratory complication was experienced by the patient. Maintaining the spontaneous breathing in cases of abdominal surgery using epidural anesthesia combined with light general anaesthesia is an excellent option for patients with other ailments complicated with COPD. The next case presents a successful continuous spinal anaesthetic in a 55 year old woman, oxygen dependent (at 2L/min) patient with COPD (severe end -stage emphysema) and preoperative baseline hypercapnia that exceeds 100 mm mercury (Sprung et. al, 1998). The patient's main complaint was 6 weeks of progressively increasing numbness and coldness of the left leg and pain of the left toe. The authors reported that "An angiogram revealed occlusion of the left superficial femoral artery with distal flow in the area supplied by the 9 popliteal artery () the course of the vascular disease and the present level of patient's continuous discomfort required left lower extremity revascularization" (Case report, 1st par.). Furthermore, the patient was orthopneic and depend on accessory respiratory according to the doctors. The anaesthetic plan was to provide continuous spinal anaesthesia, close monitoring and an arterial line placement. The surgery required nasal administration of oxygen at 2L/min. An epidural set was used to ensure continuous spinal anaesthesia to the patient while at sitting position. The initial anaesthesia consisted of 7.5 mg isobaric, 0.5% bupicaine followed by 5 mg dose 15 minutes after. According to the doctors, the BP at that time was 150/75 mm Hg and heart rate of 75bpm. A good sensory and motor block was achieved at T10 level but the patient still felt the placement of the Foley catheter. An additional 3mg of 0.75% hyperbaric bupivacaine was given resulting to 130/60 mm Hg BP and heart rate of 80bpm. The patient did well while in sitting position for the first 3 hours until an additional 5mg of 0.5% isobaric bupivacaine was administered in response to leg movement due to inadequate anaesthesia. The response of the patient according to the doctors was BP of 65/35 mm Hg and heart beat of 98 bpm and coincided with acute respiratory distress, confusion and air gasping. In response, several IV boluses of 100 pg phenylephrine and 5mg of ephedrine and fast infusion of 1L of crystalloid solution which increased the BP to 120/80 mm Hg were done. The patient always gasp for breathe every time the BP register to 90 mm Hg. This was treated by introduction of additional fluids and boluses of ephedrine. Finally, the patients BP stabilized after sufficient IV fluids and 3 U of packed red cells were administered. When the surgery was completed, the patient was transferred to ICU, her BP was 120/70 mm Hg. Her recovery Was remarkable according to the doctors and the breathing pattern were comparable to preoperative condition. The postoperative pain was treated by continuous administration of 0.0625% bupivacaine at the rate of 0.75 ml/hour through intrethecal catheter (11.3 mg of buprivacaine over 24 hours). The catheter was removed on the 2nd day of postoperation, transferred to regular nursing unit the same day and discharged on the 5th postoperative day . The authors concluded that, "despite severe dyspnea at rest, low spirometric values, and 10 severe hypercapnia, elective peripheral vascular surgery can be accomplished with a carefully performed regional anesthetic technique, provided that hemodynamic stability and oxygen carrying capacities are maintained" (Discussion, 4th par.). Summary and Conclusion The use of general anaesthesia in cases of patients with severe COPD offer theoretical advantages as it ensures full cooperation from the patient and allow the possibility of suction of secretions in the bronchus. This not possible with regional anaesthesia as airway manipulation cannot be done as well as the minimal alteration of blood gases and maintenance of ventilatory control. All of these proved advantageous for COPD patient's well being. It was proven by the cases presented that regional anaesthesia though may seem practical may not be suited for all COPD patients and in all cases. Regional anaesthesia is not practical because excessive blockade may possibly weaken the respiratory muscles and result to impaired cough. It was proven from the case presented that in spinal anaesthesia, slight hypoventilation occurred in elderly patients. This condition usually result to impaired gas distribution and ventilation-perfusion mismatch during the postoperative recovery phase of the patient. Other doctors claimed that in midthorasic level of spinal anaesthesia, only a clinically insignificant impairment of forced expiratory muscle function was observed and alveolar ventilation, blood gas tensions and exchange of respiratory gas were not affected. From the analysis of the cases presented, it appears that regional anaesthesia provide superior anaesthetic management for COPD patients. This is due to the fact that normally patients who underwent regional anaesthesia doesn't require mechanical ventilation during the postoperative recovery period. As proof to the morbidity safeness of regional over general anaesthesia, Tarhan et al. (cited in Sprung et. al, 1998) reported no deaths in 121 surgical patients with moderate to severe chronic pulmonary ailments who underwent spinal or epidural anaesthesia; however, the author reported that 33 of 464 patients who had general anaesthesia died from respiratory failure. The author further claimed that thorasic and upper 11 abdominal surgeries with general anaesthesia registered higher mortality rate. There is no available literature showing evidence that specific anaesthetic technique is superior to others in patients with end-stage COPD. It appears that the last case although it entailed a lot of monitoring and professional work is the most practical from the point of view of patients well being during the postoperative stage. Elective surgery can be resorted to in patients with severe respiratory dysfunction, one that permanently require oxygen supply accessory by titrating the local anaesthetic during the continuous spinal anaesthesia. However, this technique require close monitoring of cardiac output and hemoglobin concentration preservation. Continuous titration of anaesthetic substances to achieve stability of the patient and maintaining optimal analgesic effect to ensure minimal respiratory problem impact result to higher morbidity safety margin and lesser time needed for excellent postoperative recovery. 12 Works Cited American Thorasic Society. (ca 2007). Standards for the Diagnosis and Management of patients with COPD [on line].2004 American Thorasic Society and European Respiratory Society. Available from< https://www.thoracic.org/sections/copd/resources/copddoc.pdf> [Accessed 18 September 2008] Buist, S. (2007). Global Strategy for the Diagnosis, Management and Prevention of Chronic Obstructive Pulmonary Disease. In Global Initiative for Chronic Obstructive Lung Disease. Updated 2007. Medical Communications Resources, Inc. Leech, C., Baba, A., and Dhar, M. (2006).Spinal anaesthesia and non-invasive positive pressure ventilation for hip surgery in an obese patient with advanced chronic obstructive pulmonary disease. British Journal of Anaesthesia, 13(1), 763-5. Mark Bowes. (ca 2007). Management of COPD: An Update [on line]. In AAFP Video CME Program. American Academy of Family Physicians. Available from: http://www.aafp.org/PreBuilt/videocme/copdupdate_mono.pdf [Accessed 19 September 2008] Mannino DM, Homa DM, Akinbami LJ, Ford ES, Redd SC. (2002) Chronic obstructive pulmonary disease surveillance - United States, 1971-2000. MMWR 2002; 51: 1-16. Murray CJL, Lopez AD. (1997) Alternative projections of mortality and disability by cause 1990-2020: Global Burden of Disease Study. Lancet 1997; 349: 1498-1504. Rutkowska, K., Misioek, H., Kucia, H., and Knapik, P. (2006). Perioperative management of COPD patients undergoing nonpulmonary surgery. Anaesthesiology Intensive Therapy. 38, 153-157. Sprung, J., Correia, R., Shoenwald, P., Bhambini, R., and O'Hara, P. (1998). A Successful Continuous Spinal Anesthetic in a Patient with Preoperative Baseline Hypercapnia Exceeding 100 mm Hg. Anaesth Analg. 86: 591-3. Read More