Difficulty Weaning Research Articles

Difficult weaning from mechanical ventilation in the pediatric ICU

Background Respiratory disorders are the main cause of respiratory failure in children. Insufficient alveolar ventilation results in hypoxemia and hypercapnia, which contribute to further depression of ventilation, resulting in respiratory failure. Although most patients wean from mechanical ventilation with little difficulty, some patients are unable to maintain sustained efforts of breathing for long periods and develop signs of fatigue. A failed weaning is defined as either the failure of spontaneous breathing trial or the need for reintubation within 48 h after extubation. Objective This study was undertaken to identify the causes of difficult weaning from mechanical ventilation and predict the variables responsible for this difficulty. Participants and methods A prospective study was performed on 100 children, comprising 59 boys and 41 girls. Their ages ranged between 2 months and 10 years. All the children were subjected to a detailed medical history taking, clinical examination, and laboratory investigations (complete blood count, serum electrolytes, and arterial blood gas). Patients were selected to participate in this study on the basis of the inclusion and exclusion criteria. Statistical analysis The Mann-Whitney U -test and the χ 2 -test were used for statistical analysis. Results Among the 100 studied patients, 86 (86%) succeeded in being weaned from mechanical ventilation, whereas the remaining 14 patients (14%) failed to wean. This group included nine children who experienced difficulty in weaning and five children with prolonged weaning. Patients who were successfully weaned spent statistically less time on mechanical ventilation, had lower PaCO 2 , and lower bicarbonate level compared with patients who failed to wean ( P = 0.002, 0.001, 0.04, respectively). There was no association between clinical diagnosis, hematological parameters, serum electrolytes, and weaning success. Conclusion We conclude that patients who were successfully weaned were statistically older, spent less time on mechanical ventilation, had lower PaCO 2 and FiO 2 , and lower bicarbonate level compared with those who failed to be weaned. We did not find a significant relation between the clinical diagnosis, hematological parameters, serum electrolytes, and weaning success.

Late Presentation of Recurrent Monomorphic Ventricular Tachycardia following Minimally Invasive Mitral Valve Repair due to Epicardial Injury.

We report a 73-year-old male with late onset monomorphic ventricular tachycardia following mitral valve repair (MVR). Typically, injury to epicardial arteries following mitral valve repair/replacement presents immediately as ventricular tachycardia/fibrillation, difficulty weaning from cardiopulmonary bypass, worsening ECG changes, increasing cardiac biomarkers, or new wall motion abnormalities. Our case illustrates a “late complication” of a distorted circumflex artery following mitral valve repair and the importance of early diagnostic angiography and percutaneous intervention.

1286

Introduction: A 68 year-old man with chronic alcohol abuse and recent COPD exacerbation was admitted to our surgical ICU after a laparotomy for a small bowel obstruction. He was started on a lorazepam revised Clinical Institute Withdrawal Assessment of Alcohol (CIWA-Ar) scale to help in the assessment and management of alcohol withdrawal syndrome (AWS). His post-operative course was complicated by respiratory distress requiring intubation. On hospital day 5, he was switched from lorazepam to PO vodka for AWS prevention due to a concern that lorazepam was causing oversedation, resulting in difficulty weaning from the ventilator. After a 24-hour trial of oral vodka was conducted, at 30ml every 6 hours, the patient was switched back to lorazepam due to escalating AWS. This medical case led to significant discussion among the medical teams involved regarding patient selection, indications, and evidence for this age-old, but controversial, therapy. Hospitalized patients with histories of chronic alcohol abuse risk developing AWS during their hospital course, and often require care in the ICU due to potentially lethal complications, such as seizures and delirium. Clinically, AWS is commonly defined as alcohol withdrawal symptom severity resulting in a CIWA-Ar score of greater than 20. Current first-line prophylaxis of AWS in SICU patients is intravenous (IV) benzodiazepines. CIWA-Ar score is evaluated every hour until a score of less than 10 has been maintained for at least 24 hours. If the CIWA-Ar score rises above 20, treatment should be initiated with higher doses of benzodiazepines. Historically ethanol has been used as an alternative for preventing AWS, particularly in surgical patients, but current literature on its use is lacking. Available research addresses IV ethanol for AWS prevention, and advises against its use because of the high cost, narrow therapeutic index, and unpredictable pharmacokinetics. Compared to benzodiazepines, oral (PO) ethanol may cause less sedation and respiratory depression at effective doses. Pharmacy cost-containment strategies may favor PO over more costly IV ethanol formulations. Despite its long-standing, therapeutic considerations, current literature is heavy weighted against the use of PO ethanol for AWS prevention, primarily due to the paucity of data validating its use. Nonetheless, many hospitals nationwide have PO ethanol available for patients with histories of alcohol abuse. At our institution, the Medication Safety and Quality Committee recently approved the use of PO ethanol for AWS prevention in surgical patients undergoing thoracic and head and neck procedures, given the high prevalence of alcohol abuse in these cohorts. Available literature suggests that use of PO ethanol is most effective when administered using a protocol, but a validated protocol has yet to be published. Our pharmacy recommends the use of 40% vodka in 30 mL doses (13g of ethanol) every 4 to 8 hours, with a starting dose of 0.5-1g/kg/day. The vodka is purchased by the pharmacy's supplier, stored in the pharmacy, and administered as a nonformulary drug. Due to potential drug interactions, additional precautions must be taken when using PO ethanol, including discontinuation of NSAIDs and/or the addition of GI prophylaxis, limitation of acetaminophen doses to under 2g/day, and the discontinuation of drugs that may cause a disulfiram-like reaction, such as metronidazole. In addition to logistical issues with its administration, many physicians ethically object to prescribing ethanol to patients who are addicted to alcohol. More research is needed regarding which patients may benefit from PO ethanol over standard first-line benzodiazepine therapy, and how to safely and effectively administer ethanol to these patients.

DILATIVE VASCULOPATHY AND CEREBRAL HAEMORRHAGE AS A PRESENTATION OF LATE–ONSET POMPE DISEASE

A 51 year old gentleman who had experienced a spontaneous intracerebral haemorrhage was referred for a neurological opinion when the anaesthetists experienced difficulty weaning him from the ventilator on the...

Isolated Right Superior Vena Cava Into the Left Atrium Detected by Contrast Echocardiography

The patient is a 56-year-old woman admitted to the Intensive Care Unit for an acute traumatic subdural hematoma. Her medical history was significant for progressive, severe hypoxia reported to be secondary to chronic obstructive pulmonary disease, despite absence of supporting pathology on chest radiogram (Figure 1). An electrocardiogram on admission revealed sinus rhythm with left atrial enlargement and a prolonged QT (Figure 2). She underwent emergent craniectomy and evacuation, thereafter experiencing a prolonged Intensive Care Unit course with difficulty weaning off mechanical ventilation. During the hospitalization, intravenous access was obtained with a subclavian venous line (Figure 1). Intravenous agitated saline was injected into this subclavian line under echocardiographic guidance to confirm correct line placement. Within seconds, saline microbubbles were visualized in the left atrium (LA), without transit …

Are intraoperative precursor events associated with postoperative major adverse events?

Precursor events are undesirable events that can lead to a subsequent adverse event and have been associated with postoperative mortality. The purpose of the present study was to determine whether precursor events are associated with a composite endpoint of major adverse cardiac events (MACE) (death, acute renal failure, stroke, infection) in a low- to medium-risk coronary artery bypass grafting, valve, and valve plus coronary artery bypass grafting population. These events might be targets for strategies aimed at quality improvement. The present study was a retrospective cohort design performed at the Queen Elizabeth Health Science Centre. Low- to medium-risk patients who had experienced postoperative MACE were matched 1:1 with patients who had not experienced postoperative MACE. The operative notes, for both groups, were scored by 5 surgeons to determine the frequency of 4 precursor events: bleeding, difficulty weaning from cardiopulmonary bypass, repair or regrafting, and incomplete revascularization or repair. A univariate comparison of ≥1 precursor events in the matched groups was performed. A total of 311 MACE patients (98.4%) were matched. The primary outcome occurred more frequently in the MACE group than in the non-MACE group (33% vs 24%; P=.015). The incidence of the individual events of bleeding and difficulty weaning from cardiopulmonary bypass was significantly higher in the MACE group. Those patients with a precursor event in the absence of MACE also appeared to have a greater prevalence of other important postoperative outcomes. Patients undergoing cardiac surgery who are exposed to intraoperative precursor events were more likely to experience a postoperative MACE. Quality improvement techniques aimed at mitigating the consequences of precursor events might improve the surgical outcomes for cardiac surgical patients.

Difficulty Weaning Off Cardiopulmonary Bypass: Role of Diabetes-Associated Cardiomyopathy

Diabetes mellitus is a progressive systemic disease that adversely affects cardiovascular function. Diabetesassociated cardiovascular changes are a major cause of morbidity and mortality worldwide. Clinical trials indicate that diabetes accelerates and worsens the prognosis of coronary atherosclerosis, is associated with a 3-fold increase in the incidence of heart failure and that it is independently associated with worse heart failure prognosis [1]. The prognostic implications of thought of specific diabetes-induced structural, metabolic and functional cardiovascular changes triggered scientists to introduce the term (diabetic cardiomyopathy, DCM) as a separate clinical phenotype of myocardial dysfunction [2].

Tracheal extubation under deep sevoflurane anesthesia: A novel strategy for weaning difficulties in intensive care

Various criteria for weaning patients from ventilators in intensive care have been widely published. These criteria are increasingly incorporated into guidelines, protocols, and more recently, care pathways. We present a case where a patient’s lungs were ventilated for 4 days with an infective exacerbation of chronic obstructive pulmonary disease (COPD). We successfully weaned off mechanical ventilation and rapidly extubated the patient’s trachea utilizing deep sevoflurane anesthesia. Published weaning indices suggest that this would have been an inappropriate course of action at the time. However, our patient clearly benefited and avoided the need for tracheostomy and prolonged ventilation.

Cardiopulmonary bypass weaning difficulty due to anomalous origin of coronary artery -A case report-

We report a case of hemodynamic instability after aortic valve replacement, due to the anomalous origin of the right coronary artery. During the cardiopulmonary bypass weaning process, hemodynamic instability occurred. The cause was not identified at first, and compression of the anomalous right coronary artery was thought to be the culprit, thereafter.

Weaning from cardiopulmonary bypass

The main goal of weaning from cardiopulmonary bypass (CPB) is a smooth transition from mechanical pump-assisted circulation to spontaneous heart activities with sufficient blood flow to maintain systemic circulation. Before initiation of weaning from the CPB, optimal condition for re-beating should be prepared. Normothermia (core temperature > 36℃) is achieved by actively re-warming through the CPB heat exchanger, active warming devices. However, core temperature should not be exceeded by more than 38℃ to avoid postoperative neurological dysfunction [1]. The findings of laboratory data should be within normal ranges. Arterial blood gas analysis is carried out to identify oxygen content of the blood as hematocrit (> 25%), hemoglobin (> 7 g/dl), PaO2 (> 100 mmHg) and absence of metabolic, electrolytic disturbances. The anesthesiologists restart sleeping alarms and adjust monitors, ventilator settings and oxygen flows. After aortic declamping, heart re-beat spontaneously in most cases with minor supportive interventions such as electrical defibrillation, pace maker, and small dose of inotropics. Atrial kick contributes more than 20% of ventricular filling, returning and maintaining of normal sinus rhythm (heart rate between 70-100 beats per min) is preferable. Electric conversion of supraventricular tachycardia, atrial fibrillation and temporary cardiac pacing for atrioventricular conduction block should be considered. Optimized preload is achieved by volume control, mean arterial pressure maintained within 70-90 mmHg with vasoactive agents. In case of inability to wean from CPB despite preload optimization, global cardiac function and completeness of surgery should be assessed by transesophageal echocardiography (TEE) examination. Most common causes of weaning difficulty are left and/or right ventricular failures and inappropriate vasodilatation. TEE allows diagnostic and therapeutic decision makings, and appropriate treatment option. Routine TEE examinations before terminating the CPB is essential for detecting unexpected problems such as an iatrogenic aortic dissection from arterial cannulation site or intracardiac thrombus formations even after full heparinization or any other anatomical anomalies [2,3]. Because of major complication of TEE probe insertion is the esophageal injury, anesthesiologists carefully manipulate TEE probe, especially patient with an esophageal pathology preoperatively [4]. Faultiness of surgery should be excluded (valvular dysfunction, coronary graft failure, left ventricular outflow obstruction) by TEE examinations, and vasoplegic syndrome managed by vasopressor administration [5]. The recently emerged minimally-invasive hemodynamic monitoring devices can assess the cardiac output, preload, intrathoracic volume and tissue oxygenation which might be guide weaning management with real time inspections of responsiveness of fluid loading and vasoactive agents [6]. Patients with risk factor of ventricular dysfunction (elderly, chronic beta-blocker treatment, renal failure, pulmonary hypertension) tend to be difficult in weaning from CPB, awareness of these risk factors are important for preparing and planning aggressive cardiosupportive management earlier as prophylactic intervention [7]. Protamine sulfate is administrated slowly in order to neutralize generalized heparinization. Thromboelastography as a point-of-care monitoring device can provide rapid information about global hemostatic states (from clot formation, stabilization to fibrinolysis) to achieve goal oriented transfusions during the cardiac operation [8]. Weaning from CPB is associated with complicated problems and requires multiplinary approaches simultaneously. According to observational studies, there were strong correlations between the technical errors and teamwork disruptions caused by poor communication and lack of information during weaning period in cardiac teams [9]. The weaning moment is a critical time for confirming and verifying surgical results and achieving the optimization of hemodynamics. Thus, important information and process should be shared and fully communicated among the anesthesiologist, the cardiac surgeon, and the perfusionist.

Successful weaning from mechanical ventilation in the quadriplegia patient with C2 spinal cord injury undergoing C2-4 spine laminoplasty -A case report-

In patients with cervical spine injuries, respiratory function requires careful attention. Voluntary respiratory control is usually possible with lesions below C4 level although paralysis of the abdominal musculature results in a decreased ability to cough and to clear secretions, which may later lead to respiratory insufficiency. Therefore, injuries above C5 usually necessitate long term mechanical ventilation. Even though weaning criteria are not definitive for the quadriplegic patient, M-mode ultrasonography of the diaphragm may be useful in identifying patients at high risk of difficulty weaning. Diaphragmatic dysfunction (vertical excursion < 10 mm or paradoxical movements) results in frequent early and delayed weaning failures. We present our clinical experience with successful weaning by using M-mode ultrasonography and a cough-assist device for secretion clearance after extubation in a quadriplegic patient undergoing C2-4 spine laminoplasty.

Le traitement de la dépendance du tabac

SUMMARY Several studies show that more than 60 to 70% of smokers want to stop smoking. The main difficulty in smoking weaning is usually important and is related to a physical and psychological smoking dependence. Smoking is considered as a chronic disease that often requires support in the long term, both pharmacological and psychological management. Smoker's motivation is a key element to start smoking weaning and to maintain it. In the first time, the management of smoking dependence is conducted by primary care doctors or by all specialized doctors graduated in this field. In case of difficulty, a recover by specialized physicians implicating in this management is desirable. The organizing of Tobacology Coordination Unit (TCU) in hospitals is also necessary. The physicians of TCU treat hospitalized patients and who are presents in consultation department. For a pragmatic point of view, it is necessary to establish a hierarchy of objectives: total stop smoking is both initial and final objective of the management of cigarette smoking weaning in smoker. The reduction of tobacco consumption in patients who do not want and / or can not quit smoking despite well conducted weaning attempts, should be considered as an intermediate step towards a definitive smoking weaning.

Congenital Central Hypoventilation Syndrome with PHOX2B Gene Mutation

A term baby developed hypoventilation on day 1 of life requiring mechanical ventilation and had subsequent difficulty in weaning. Diagnostic workup for pulmonary, cardiac, metabolic, sepsis and structural CNS diseases were negative. In view of persistent hypoventilation despite raised pCO(2) levels in absence of any sedation, the diagnosis of Idiopathic. Congenital Central Hypoventilation Syndrome (CCHS) was considered. The baby was tested for Paired-like Homeobox 2B (PHOX2B) gene mutation and was found to have expanded alleles containing 10 polyalanine repeats producing genotype of 20/30 on chromosome 4p12 (The normal being 20/20). This is the first report of a neonate from India with genetically confirmed CCHS.

An innovative method of pediatric chest wall reconstruction using Surgisis and swinging rib technique

PurposeHerein, we describe a new surgical approach for chest wall reconstruction using a native supporting rib and Surgisis. MethodsA retrospective review of 3 cases from 2 tertiary pediatric health care centers presenting with chest wall defects in the neonatal period was performed. Perioperative data were collected. ResultsTwo chest wall deformities were diagnosed at birth (Poland syndrome and cleft sternum). One patient was diagnosed prenatally with a mediastinal mass. The first infant had absent ribs 2 through 9. He underwent chest wall reconstruction at 4 weeks of life because of difficulty weaning from ventilation related to paradoxical breathing. The hamartoma of the second asymptomatic patient was removed at 6 weeks. The third patient's V-shaped sternal defect encompassed through the upper two thirds of the sternum and was repaired at 6 months of age with intraoperative transesophageal echocardiogram monitoring. In all cases, Surgisis (collagen matrix) was used as an onlay patch. In 2 cases, a swinging rib acted supportive. Neither patient had intraoperative complications. ConclusionSurgisis is useful in pediatric chest wall reconstruction, particularly in combination with swinging ribs. The capacity for adaptation to the child's growth of this approach is crucial. Short-term safety is shown, but long-term assessment is required.

PEO1 Gene (Twinkle) Mutation and Multi-Organ Failure Following Propofol Infusion (IN7-1.005)

Objective: Present a case of mitochondrial myopathy and multi-organ failure following propofol infusion. Background Mitochondrial DNA deletions are associated with a variety of clinical syndromes including chronic progressive external ophthalmoplegia (CPEO) due to nuclear as opposed to mitochondrial mutations. The nuclear PEO1 gene encodes for Twinkle, a helicase required for mitochondrial DNA replication and stability. Clinically, autosomal dominant Twinkle mutations are associated with CPEO. POLG mutations result in defects in the DNA polymerase gamma and can be associated with either autosomal dominant or autosomal recessive CPEO. Mitochondrial myopathies are associated with a sensitivity to propofol, and patients are more susceptible to developing a propofol infusion syndrome with resultant multi-organ dysfunction. Design/Methods: Literature review and illustrative case. Results: A 62-year old woman with a history of congenital ptosis and ophthalmoplegia was admitted for elective right eye enucleation for a corneal ulcer following levator resection. During the procedure, she was given propofol for anesthesia and the surgery was uneventful. Postoperatively, she developed a series of medical complications including Takotsubo cardiomyopathy, congestive heart failure, acute renal failure, and encephalopathy. She also developed dysarthria, bifacial and proximal muscle weakness, and difficulty weaning from the ventilator. Muscle biopsy was done showing a mitochondrial myopathy with scattered ragged red fibers and cytochrome oxidase negative muscle fibers. Genetic analysis showed nuclear mutations in the PEO1 and POLG genes. Conclusions: This patient had a mitochondrial myopathy presenting with CPEO, and after elective surgery, developed muti-organ dysfunction. She had the PEO1 mutation in addition to a POLG mutation. The literature on propofol use in mitochondrial myopathies is limited, but it has been associated with propofol infusion syndrome, and may have led to her poor clinical course. Disclosure: Dr. Harrison has nothing to disclose. Dr. Valerio has nothing to disclose. Dr. Buffam has nothing to disclose. Dr. Mezei has received personal compensation for activities with Genzyme as a speaker.

Mechanical ventilation induces a time‐dependent reduction in microvascular oxygenation and vascular conductance in the diaphragm

Prolonged mechanical ventilation (MV) promotes diaphragmatic atrophy and contractile dysfunction, collectively termed ventilator‐induced diaphragmatic dysfunction. A local mismatching of O2 delivery (QO2) to consumption (VO2) within the diaphragm may contribute, in part, to muscle dysfunction and weaning difficulties following MV. We tested the hypotheses that longer durations of MV (i.e., 6 hrs.) will 1) cause a mismatching of QO2‐to‐VO2, evident through a reduction microvascular PO2 (i.e., PO2m); and 2) reduce vascular conductance (VC) compared to acute MV (i.e., 30 min). Diaphragm PO2m and VC were measured in vivo in adult female Sprague‐Dawley rats (n=15). Data was collected during spontaneous breathing (SB) and after acute MV and 6 hr of MV. PO2m in the diaphragm was significantly reduced following the onset of MV (SB: 53±6, acute MV: 37±8 mmHg; P&lt;0.05) and by an additional ~51% after 6 hr (versus acute MV) to 18±5 mmHg (P&lt;0.05). Diaphragm VC was diminished after the onset of MV (SB: 0.36±0.02, acute MV: 0.24±0.02) and reduced further after 6 hr MV (0.08±0.01 ml/min/100 g/mmHg; all P&lt;0.05). The diminished microvascular driving pressure of O2 and VC provides important insight, and a potential contributing mechanism, into the inadequate maintenance of the QO2‐to‐VO2 ratio in the diaphragm with prolonged MV. The mechanisms responsible for the reduced PO2m and VC with MV require further studies. (NIH and FBRP)

Inspiratory Muscle Strength Training in Infants With Congenital Heart Disease and Prolonged Mechanical Ventilation: A Case Report

Inspiratory muscle strength training (IMST) has been shown to improve maximal pressures and facilitate ventilator weaning in adults with prolonged mechanical ventilation (MV). The purposes of this case report are: (1) to describe the rationale for IMST in infants with MV dependence and (2) to summarize the device modifications used to administer training. Two infants with congenital heart disease underwent corrective surgery and were referred for inspiratory muscle strength evaluation after repeated weaning failures. It was determined that IMST was indicated due to inspiratory muscle weakness and a rapid, shallow breathing pattern. In order to accommodate small tidal volumes of infants, 2 alternative training modes were devised. For infant 1, IMST consisted of 15-second inspiratory occlusions. Infant 2 received 10-breath sets of IMST through a modified positive end-expiratory pressure valve. Four daily IMST sets separated by 3 to 5 minutes of rest were administered 5 to 6 days per week. The infants' IMST tolerance was evaluated by vital signs and daily clinical reviews. Maximal inspiratory pressure (MIP) and rate of pressure development (dP/dt) were the primary outcome measures. Secondary outcome measures included the resting breathing pattern and MV weaning. There were no adverse events associated with IMST. Infants generated training pressures through the adapted devices, with improved MIP, dP/dt, and breathing pattern. Both infants weaned from MV to a high-flow nasal cannula, and neither required subsequent reintubation during their hospitalization. This case report describes pediatric adaptations of an IMST technique used to improve muscle performance and facilitate weaning in adults. Training was well tolerated in 2 infants with postoperative weaning difficulty and inspiratory muscle dysfunction. Further systematic examination will be needed to determine whether IMST provides a significant performance or weaning benefit.

The effect of neoadjuvant chemoradiotherapy on airway colonization and postoperative respiratory complications in patients undergoing oesophagectomy for oesophageal cancer

Respiratory complication is one of the important postoperative complications of oesophageal cancer. The aim of this study was to evaluate whether neoadjuvant chemotherapy before surgery is effective for postoperative respiratory complications. In this study, patients with oesophageal cancer were divided into two group: one with neoadjuvant therapy and the other without neoadjuvant therapy. Before surgery, they all underwent bronchoscopy and bronchoalveolar lavage. We evaluated respiratory complications and the effects of preoperative neoadjuvant therapy. Forty patients (M/F = 23/17 and mean age 61 years) were enrolled in this study. Twenty-two cases had cancer in the middle part and 18 in the lower part of the oesophagus. Significant correlation was observed between the number of positive micro-organism and difficulty in weaning and receiving neoadjuvant therapy. But no significant correlation was found between neoadjuvant therapy and respiratory complications.

Respiratory Dysfunction in Ventilated Patients: Can Inspiratory Muscle Training Help?

Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. Moreover, psychological influences, including anxiety, may contribute to difficulty in weaning. There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.

A12 Ischemic Heart Disease and Weaning from Mechanical Ventilation, how efficient Esmolol can be when Extubation is unsuccessful?

Background and Goal of Study: Patients with ischemic heart disease are known to tolerate hemodynamic stress poorly. As a consequence of their coronary artery disease, ischemic episodes may develop during, or shortly after tracheal tube removal. We describe a case with coronary artery disease that developed repeated episodes of pulmonary oedema each time extubation was attempted. We describe a case of patient with ischemic heart disease and the difficulties in weaning and extubation. Methods: A 70 year old male was submitted urgently because of an abdominal aneurysm. The patient was hemodynamically stable throughout the intervention that lasted 4 hours and on ICU admission, (Heart rate 100/min, and blood pressure 130/65mmHg). Despite trying twice the patient did not achieve successful extubation, in both instances, after extubation, he presented with a rapid shallow breathing and low arterial oxygen saturation. On auscultation, he presented crepitations in middle zones of both lung fields and the chest X-ray was indicative for pulmonary oedema. A trans-thoracic echo that was performed showed normal systolic ventricular function and diastolic dysfunction with abnormal relaxation, patient was therefore given initially esmolol 500 μg/kg/min (iv.) followed by an infusion of 50 μg/kg/min. Sedation was gradually decreased and infusion rate of esmolol was increased. Patient was extubated successfully under 100 μg/kg/min and was discharged from the ICU two days later. Results: Extubation stress in patients with coronary artery disease cause excessive increases in myocardial oxygen consumption thereby altering the supply/demand ratio. Our patient was experiencing ischemic left ventricular dysfunction during weaning, secondary to catecholamine release due to upper airway stimulation by the tracheal tube. This was manifested as hypertension, tachycardia and episodes of pulmonary oedema, which were rapidly resolved with sedation. Conclusions: Using esmolol, a short/acting beta/blocker, allowed successful extubation of patient who developed repeated episodes of pulmonary oedema each time extubation was attempted.