Weaning-failure patients

In a survey of intensive care units in the UK, more than two-thirds of the respondents would have chosen suxamethonium in a clinical scenario requiring re-intubation in a patient with abdominal sepsis and weaning failure after 20 days of ICU stay (198). The authors concluded that there is a lack of appreciation of the dangers of suxamethonium in critically ill patients in intensive care units. 

Gluck EH. Predicting eventual success or failure to wean in patients receiving long-term mechanical ventilation. Chest 1996 110(4) 1018-1024. 

Datta D, Scalise P. Hypothyroidism and failure to wean in patients receiving prolonged mechanical ventilation at a regional weaning center. Chest 2004 126(4) 1307-1312. 

Srivastava S, Chatila W, Amoateng-Adjepong Y, et al. Myocardial ischemia and weaning failure in patients with coronary artery disease an update. Crit Care Med 1999 27(10) 2109-2112. 

Krishan JA, Moore D, Robeson C, et al. A prospective controlled trial of a protocol-based strategy to discontinue mechanical ventilation. Am J Respir Crit Care Med 2004 169 673-678. Nava S, Amlnosino N, Clini E, et al. Noninvasive mechanical ventilation in the weaning of patients with respiratory failure due to chronic obstructive pulmonary disease. A randomized controlled trial. Ann Intern Med 1998 128 721-728. 

Only a small proportion of patients fail to wean from mechanical ventilation, but they require a disproportionate amount of resources. Weaning failure has been extensively studied in the clinical literature and several factors are likely to contribute to it. These factors include inadequate ventilatory drive, respiratory muscle weakness, respiratory muscle fatigue, increased work of breathing, or cardiac failure. There is accumulating... 

Weaning failure increases the risk of myocardial ischemia, left ventricular dysfunction, and pulmonary hypertension (27,29). In a prospective cohort study, Epstein et al. (30) evaluated medical outcomes of 42 patients reintubated after an unsuccessful extubation attempt. They noted an increase in mortality, duration of ICU and hospital stay, dependence on ventilatory support, and requirements for long-term care among these patients. Predicting failure to wean has been disappointing (15,27,31), especially among patients with neuromuscular disease who often perform better than expected (13,32). 

Patients with decompensated cardiac failure requiring the use of IV inotropic therapy (such patients should first be weaned from IV therapy before initiating carvedilol) bronchial asthma (see Warninas) or related bronchospastic conditions second- or third-degree AV block sick sinus syndrome or severe bradycardia (unless a permanent pacemaker is in place) cardiogenic shock clinically manifest hepatic impairment hypersensitivity to the drug. 

Intestinal transplantation is combined with liver transplantation in 46% of cases, because of terminal liver failure (93). Of 78 patients who had received parenteral nutrition for more than 2 years n — 66) and/ or had short bowel syndrome and could not be weaned from parenteral nutrition (n = 12), 58 developed chronic cholestasis and 37 developed one or more severe liver complication (serum bilirubin concentration 60 pmol/l, factor V (proaccelerin) 50%, portal hypertension, encephalopathy, ascites, bleeding from the gastrointestinal tract, or histological findings consisting of extensive fibrosis and cirrhosis) after 6 (3-132) months and 17 (2-155) months respectively. Liver disease was responsible for deaths in 6.5% of the patients (22% of deaths). 

Docarpamine was also shown to be an orally effective peripheral dopamine prodrug, at doses higher than ibopamine [13, 23], and it is used in Japan for weaning patients from i.v. dopamine infusion in severe heart failure. 

Worldwide mortality, studies report mortality rales of 3-25%. The compounds involved most frequently are maiathion, dichlorvos, trichlorfon, and fenthion/ malathion. Mortality rates depend on the type of compound u.sed, amount ingested, general health of the patient, delay in discovery and transport, insufficient respiratory management. delay in intubation, and failure to wean off ventilatory support. Signs and symptoms of OP poisoning can be divided into three broad categories, including muscarinic effects, nicotinic effects, and CNS effects. Complications include respiratory distress, seizures, and aspiration pneumonia. Respiratory failure is the most common cause of death. 

By shortening AV delay and reducing LV dyssynchrony, CRT can increase LV filling time, increase sttoke volume, and reduce mitral regurgitation (5,10,11). These are the underlying mechanism of acute improvement with CRT. In fact, patients frequently feel better almost immediately after implantation. Occasionally, we see patients with end-stage heart failure who cannot be weaned off inotropic support be successfully weaned 1-2 days after CRT implantation. 

Dasgupta and colleagues (1998) treated 20 patients with neoplastic tracheobronchial strictures with uncovered Wallstents. Stents were successfully deployed in all patients and airway patency was restored. Four patients were successfully weaned after stent insertion, five were receiving mechanical ventilatory assistance, while the remaining died from unrelated causes while receiving mechanical ventilatory assistance. No deaths occurred from stent failure or stent related complications. 

Liver The effect of weaning patients off PN and its relationship to liver histology has been evaluated in a study including 38 patients with paediatric intestinal failure. Abnormal histology was foxmd in 77% of patients weaned of parenteral nutrition. Portal inflammation and fibrosis were also observed [117 ]. In a prospective cohort study to determine the incidence and risk factors for development of abnormal LFTs in patients on short-term PN (8-54 days mean 15.9 days), 57.5% of 80 patients had abnormal LFTs [118 ]. Septic shock, hyperglycaemia, soybean lipid and absolute diet were associated with an increased risk of abnormal LFTs. 

In a retrospective study of 319 patients, multivariate analysis identified shock on ICU admission day as the only independent predictor for PMV (>21 days) (47). In a prehminaty study of 111 patients, increased duration of MV and need for transfer to a long-term ventilator care facility was associated with a creatinine elevation of 1.3 mg/dL anytime during the ICU stay (48). In another study, none of the 52 patients with PMV and renal failure were successfully weaned (49). Chao and colleagues reviewed >1000 patients transferred to their regional weaning center and identified 63 with renal dysfunction, with creatinine >2.5 mg/dL (40 on renal replacement therapy) (50). When compared to those with creatinine <2.5 mg/dL, patients with renal dysfunction were less likely to wean from MV (13% vs. 58%). 

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