Pablo Rodriguez

Presence and severity of intensive care unit-acquired paresis at time of awakening are associated with increased intensive care unit and hospital mortality.

Objectives: To assess whether the presence and severity of intensive care unit-acquired paresis are associated with intensive care unit and in-hospital mortality. Design: Prospective, observational study. Setting: Two medical, one surgical, and one medico-surgical intensive care units in two university hospitals and one university-affiliated hospital. Patients: A total of 115 consecutive patients were enrolled after > 7 days of mechanical ventilation. Interventions: None. Measurements and Main Results: The Medical Research Council score (from 0–60) was used to evaluate upper and lower limb strength at time of awakening, identified as the ability to follow five commands. Intensive care unit-acquired paresis was defined as a Medical Research Council score <48. Patients were followed-up until hospital discharge. The primary end point was hospital mortality. At awakening, median Medical Research Council score was 41 (interquartile range, 21–52), and 75 (65%) patients had intensive care unit-acquired paresis. Hospital non-survivors had a significantly lower Medical Research Council score at awakening (21 [11–43]) vs. 41 [28–53]; p = .008) and a significantly higher rate of intensive care unit-acquired paresis (85.1% vs. 58.4%; p = .02) compared to survivors. After multivariate risk adjustment, intensive care unit-acquired paresis was independently associated with higher hospital and intensive care unit mortality (odds ratio for hospital mortality, 2.02; 95% confidence interval, 1.03–8.03; p = .048). Each Medical Research Council point decrease was associated with a significantly higher hospital mortality (odds ratio, 1.03; 95% confidence interval, 1.01–1.05; p = .033). Conclusions: Both the presence and severity of intensive care unit-acquired paresis at the time of awakening are associated with increased intensive care unit and hospital mortality; the mechanisms underlying this association need further study.

Origin of ICU acquired paresis determined by direct muscle stimulation

Background: Acquired diffuse paresis in an intensive care unit (ICU) can result from critical illness myopathy or polyneuropathy. Clinical examination and conventional neurophysiological techniques may not distinguish between these entities. Objective: To assess the value of direct muscle stimulation (DMS) to differentiate myopathic from neuropathic process in critically ill patients with diffuse severe muscle weakness. Methods: 30 consecutive patients with ICU acquired diffuse motor weakness were studied. Responses of the right deltoid and tibialis anterior muscles to DMS and to motor nerve stimulation (MNS) were studied and compared with results of conventional nerve conduction studies and concentric needle electromyography (EMG). An original algorithm was used for differential diagnosis, taking into account first the amplitude of the responses to DMS, then the MNS to DMS amplitude ratio, and finally the amplitude of the sensory nerve action potentials recorded at the lower limbs. Results: Evidence of neuropathy and myopathy was found in 57% and 83% of the patients, respectively. Pure or predominant myopathy was found in 19 patients. Other results were consistent with neuromyopathy (n = 5) and pure or predominant neuropathy (n = 2). Four patients had normal results with stimulation techniques, but spontaneous EMG activity and raised plasma creatine kinase suggesting necrotic myopathy. Conclusions: A neurophysiological approach combining DMS and conventional techniques revealed myopathic processes in a majority of ICU patients. Reduced muscle fibre excitability may be a leading cause for this. The diagnosis of myopathy in ICU acquired paralysis can be established by a combination of DMS, needle EMG, and plasma creatine kinase.

Muscle weakness in septic patients requiring mechanical ventilation: Protective effect of transcutaneous neuromuscular electrical stimulation ☆

PURPOSE The aim of this study was to evaluate the effect of transcutaneous neuromuscular electrical stimulation (NMES) on muscle strength in septic patients requiring mechanical ventilation (MV). METHODS Sixteen septic patients requiring MV and having 1 or more organ failure other than respiratory dysfunction were enrolled within 48 hours from admission to the intensive care unit. Neuromuscular electrical stimulation was administered twice a day on brachial biceps and vastus medialis (quadriceps) of 1 side of the body until MV withdrawal. Blinded investigators measured arm and thigh circumferences, biceps thickness by ultrasonography, and muscle strength after awakening with Medical Research Council scale. RESULTS Two patients died before strength evaluation and were excluded from the analysis. Neuromuscular electrical stimulation was applied for 13 days (interquartile range, 7-30 days). Biceps (P = .005) and quadriceps (P = .034) strengths were significantly higher on the stimulated side at the last day of NMES. Improvement was mainly observed in more severe and weaker patients. Circumference of the nonstimulated arm decreased at the last day of NMES (P = .015), whereas no other significant differences in limb circumferences or biceps thickness were observed. CONCLUSION Neuromuscular electrical stimulation was associated with an increase in strength of the stimulated muscle in septic patients requiring MV. Neuromuscular electrical stimulation may be useful to prevent muscle weakness in this population.

Transpulmonary Pressure and Gas Exchange During Decremental PEEP Titration in Pulmonary ARDS Patients

BACKGROUND: Selection of the PEEP associated with the best compliance of the respiratory system during decremental PEEP titration can be used for the treatment of patients suffering from ARDS. We describe changes in transpulmonary pressure (Ptp) and gas exchange during a decremental PEEP titration maneuver in subjects with pulmonary ARDS. METHODS: Eleven subjects with early ARDS were included. After a recruitment maneuver they were ventilated in volume-controlled ventilation and PEEP was decreased from 30 to 0 cm H2O by steps of 3 cm H2O. Static airway pressure (Paw), esophageal pressure (Pes), Ptp (Paw – Pes), the ratio of dead space to tidal volume (VD/VT), and PaO2 were recorded at each step. RESULTS: A linear correlation was found between Paw and Ptp. Expiratory Ptp became negative in all subjects when PEEP decreased below 8.9 ± 5.2 cm H2O. VD/VT was 0.67 ± 0.06 with 30 cm H2O of PEEP, and decreased 15.4 ± 8.5% during the maneuver, when PEEP and expiratory Ptp were 10.6 ± 4.1 cm H2O and 1.2 ± 2.8 cm H2O, respectively. VD/VT was significantly higher during ventilation at high (> 18 cm H2O), compared to low, inspiratory Ptp values (P < .001). PaO2 decreased when expiratory Ptp became negative (P < .001). CONCLUSIONS: During decremental PEEP titration we sequentially observed high inspiratory Ptp that stressed lung tissue and increased VD/VT, and negative Ptp, indicating high risk of alveolar collapse, explaining worse oxygenation. PEEP selection based on Ptp and VD/VT in ARDS may help to avoid these situations.

Hormonal status in protracted critical illness and in-hospital mortality

IntroductionThe aim of this study was to determine the relationship between hormonal status and mortality in patients with protracted critical illness.MethodsWe conducted a prospective observational study in four medical and surgical intensive care units (ICUs). ICU patients who regained consciousness after 7 days of mechanical ventilation were included. Plasma levels of insulin-like growth factor 1 (IGF-1), prolactin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, estradiol, progesterone, testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS) and cortisol were measured on the first day patients were awake and cooperative (day 1). Mean blood glucose from admission to day 1 was calculated.ResultsWe studied 102 patients: 65 men and 37 women (29 of the women were postmenopausal). Twenty-four patients (24%) died in the hospital. The IGF-1 levels were higher and the cortisol levels were lower in survivors. Mean blood glucose was lower in women who survived, and DHEA and DHEAS were higher in men who survived.ConclusionsThese results suggest that, on the basis of sex, some endocrine or metabolic markers measured in the postacute phase of critical illness might have a prognostic value.

Gas exchange and lung mechanics in patients with acute respiratory distress syndrome: Comparison of three different strategies of positive end expiratory pressure selection

PURPOSE The purpose of the study was to compare gas exchange and lung mechanics between different strategies to select positive end-expiratory pressure (PEEP) in acute respiratory distress syndrome (ARDS). METHODS In 20 consecutive ARDS patients, 3 PEEP selection strategies were evaluated. One strategy was based on oxygenation using the ARDS network PEEP/fraction of inspired oxygen (Fio2) table; and two were based on lung mechanics, either PEEP titrated to reach a plateau pressure of 28 to 30 cm H2O as in the ExPress trial or best respiratory compliance method during a derecruitment maneuver. Gas exchange, airway pressures, stress index (SI), and end-expiratory transpulmonary pressure (P(tpe)) and end-inspiratory transpulmonary pressure (P(tpi)) values were assessed. Data are expressed as median (interquartile range [IQR]). RESULTS Lower total PEEP levels were observed with the use of the PEEP/Fio2 table (8.7 [6-10] cm H2O); intermediate PEEP levels, with the Best Compliance approach (13.0 [10.2-13.8] cm H2O); and higher PEEP levels, with the ExPress strategy (16.5 [15.0-18.5] cm H2O) (P < .01). Pao2/Fio2 ratio was lower with the PEEP/Fio2 table. Oxygenation with Best Compliance approach and ExPress strategy was not different with lower plateau pressure in the former (23 [20-25] vs 30 [29-30] cm H2O; P < .01). Paco2 was slightly higher with the ExPress method than the others 2 strategies. Negative P(tpe) was observed in 35% of the patients with the PEEP/Fio2 table, in 15% applying the Best Compliance, and in only 1 case with the ExPress method. Higher SI and P(tpi), with lower lung compliance, were obtained with ExPress strategy. CONCLUSIONS Using a best respiratory compliance approach resulted in better oxygenation levels without risk of overdistension according to SI and P(tpi), achieving a mild risk of lung collapse according to P(tpe).

Electrical muscle stimulation for prevention of critical illness polyneuropathy

We read with interest the study by Routsi and colleagues showing that electrical muscle stimulation (EMS) reduced the frequency of critical illness polyneuropathy in intensive care unit (ICU) patients [1] . Th e authors stated that an intention-to-treat analysis was used. One hundred and forty patients were randomized to electrical stimulation or to usual care. Measurement of the main outcome could only be performed in cooperating patients surviv ing after awakening. Th us, 39 patients (57%) and 44 patients (61%) who died or who had impaired cognitive state were excluded from analysis in each arm. Data from fi ve out of 29 subjects on the intervention arm were also excluded from the fi nal analysis because of neuro muscu lar blocker use (n = 3) or a lack of electrical stimulation during the ICU stay (n = 2). Th e latter probably induced a selection bias, as subjects receiving neuromuscular blockers have increased risk of critical illness polyneuropathy and patients with this condition have not been excluded from the usual care group [2] . Th e authors reported other outcomes such as duration of mechanical ventilation or ICU length of stay for patients with strength score evaluation, while analysis in all randomized subjects could have been valuable. Finally, reported strength scores represented the addition of upper and lower extremities, while stimulation was only applied to the latter. As systemic eff ects of EMS have not been defi nitely established in this setting, it would have been interesting to compare the strength of muscles where the intervention was tested.

Tromboembolismo pulmonar secundario a migración intrapulmonar de filtro de vena cava inferior

La enfermedad tromboembólica venosa, que incluye la trombosis venosa profunda (TVP) y el tromboembolismo pulmonar (TEP), es la tercera enfermedad cardiovascular más frecuente, después de la enfermedad coronaria y la enfermedad cerebrovascular. Presenta una alta morbimortalidad en la población general, y aún mayor en el paciente internado1,2. El tratamiento habitual de esta patología es la anticoagulación. Sin embargo, existen situaciones clínicas donde la misma se encuentra inicialmente contraindicada, o el paciente presenta recurrencia de embolismo pulmonar bajo adecuada anticoagulación. En estos casos puede recurrirse a la interrupción del flujo de la vena cava con dispositivos mecánicos, definitivos o transitorios, para prevenir el tromboembolismo pulmonar. Varias complicaciones son posibles, durante la colocación o alejadas del procedimiento. Describimos un caso de tromboembolismo pulmonar bilateral, secundario a la migración del filtro de vena cava inferior a la circulación pulmonar. Paciente masculino de 66 años, con diagnóstico de adenocarcinoma de pulmón (estadio iv, con metástasis óseas, en tratamiento con quimioterapia), que desarrolla tromboembolismo pulmonar (TEP), por lo que se indica anticoagulación con heparina, y posterior administración de dicumarínicos.