Stephen Hoffmann

Acquired Weakness, Handgrip Strength, and Mortality in Critically Ill Patients

RATIONALE ICU-acquired paresis (ICUAP) is common in survivors of critical illness. There is significant associated morbidity, including prolonged time on the ventilator and longer hospital stay. However, it is unclear whether ICUAP is independently associated with mortality, as sicker patients are more prone and existing studies have not adjusted for this. OBJECTIVES To test the hypothesis that ICUAP is independently associated with increased mortality. Secondarily, to determine if handgrip dynamometry is a concise measure of global strength and is independently associated with mortality. METHODS A prospective multicenter cohort study was conducted in intensive care units (ICU) of five academic medical centers. Adults requiring at least 5 days of mechanical ventilation without evidence of preexisting neuromuscular disease were followed until awakening and were then examined for strength. MEASUREMENTS AND MAIN RESULTS We measured global strength and handgrip dynamometry. The primary outcome was in-hospital mortality and secondary outcomes were hospital and ICU-free days, ICU readmission, and recurrent respiratory failure. Subjects with ICUAP (average MRC score of < 4) had longer hospital stays and required mechanical ventilation longer. Handgrip strength was lower in subjects with ICUAP and had good test performance for diagnosing ICUAP. After adjustment for severity of illness, ICUAP was independently associated with hospital mortality (odds ratio [OR], 7.8; 95% confidence interval [CI], 2.4-25.3; P = 0.001). Separately, handgrip strength was independently associated with hospital mortality (OR, 4.5; 95% CI, 1.5-13.6; P = 0.007). CONCLUSIONS ICUAP is independently associated with increased hospital mortality. Handgrip strength is also independently associated with poor hospital outcome and may serve as a simple test to identify ICUAP. Clinical trial registered with www.clinicaltrials.gov (NCT00106665).

Continuity of care in intensive care units: a cluster-randomized trial of intensivist staffing.

RATIONALE Little is known about the consequences of intensivists’ work schedules, or intensivist continuity of care. OBJECTIVES To assess the impact of weekend respite for intensivists, with consequent reduction in continuity of care, on them and their patients. METHODS In five medical intensive care units (ICUs) in four academic hospitals we performed a prospective, cluster-randomized, alternating trial of two intensivist staffing schedules. Daily coverage by a single intensivist in half-month rotations (continuous schedule) was compared with weekday coverage by a single intensivist, with weekend cross-coverage by colleagues (interrupted schedule). We studied consecutive patients admitted to study units, and the intensivists working in four of the participating units. MEASUREMENTS AND MAIN RESULTS The primary patient outcome was ICU length of stay (LOS);we also assessed hospital LOS and mortality rates. The primary intensivist outcome was physician burnout. Analysis was by multivariable regression. A total of 45 intensivists and 1,900 patients participated in the study. Continuity of care differed between schedules (patients with multiple intensivists = 28% under continuous schedule vs. 62% under interrupted scheduling; P < 0.0001). LOS and mortality were nonsignificantly higher under continuous scheduling (ΔICU LOS 0.36 d, P = 0.20; Δhospital LOS 0.34 d, P = 0.71; ICU mortality, odds ratio = 1.43, P = 0.12; hospital mortality, odds ratio = 1.17,P = 0.41). Intensivists experienced significantly higher burnout, work–home life imbalance, and job distress working under the continuous schedule. CONCLUSIONS Work schedules where intensivists received weekend breaks were better for the physicians and, despite lower continuity of intensivist care, did not worsen outcomes for medical ICU patients.

Treatment of septic shock in rats with nitric oxide synthase inhibitors and inhaled nitric oxide.

OBJECTIVE To evaluate the effect of treatment with a combination of nitric oxide synthase inhibitors and inhaled nitric oxide on systemic hypotension during sepsis. DESIGN Prospective, randomized, controlled study on anesthetized animals. SETTING A cardiopulmonary research laboratory. SUBJECTS Forty-seven male adult Sprague-Dawley rats. INTERVENTIONS Animals were anesthetized, mechanically ventilated with room air, and randomized into six groups: a) the control group (C, n=6) received normal saline infusion; b) the endotoxin-treated group received 100 mg/kg i.v. of Escherichia coli lipopolysaccharide (LPS, n=9); c) the third group received LPS, and 1 hr later the animals were treated with 100 mg/kg i.v. Nw-nitro-L-arginine (LNA, n=9); d) the fourth group received LPS, and after 1 hr, the animals were treated with 100 mg/kg i.v. aminoguanidine (AG, n=9); e) the fifth group received LPS and 1 hr later was treated with LNA plus 1 ppm inhaled nitric oxide (LNA+NO, n=7); f) the sixth group received LPS and 1 hr later was treated with aminoguanidine plus inhaled NO (AG+NO, n=7). Inhaled NO was administered continuously until the end of the experiment. MEASUREMENTS AND MAIN RESULTS Systemic mean blood pressure (MAP) was monitored through a catheter in the carotid artery. Mean exhaled NO (ENO) was measured before LPS (T0) and every 30 mins thereafter for 5 hrs. Arterial blood gases and pH were measured every 30 mins for the first 2 hrs and then every hour. No attempt was made to regulate the animal body temperature. All the rats became equally hypothermic (28.9+/-1.2 degrees C [SEM]) at the end of the experiment. In the control group, blood pressure and pH remained stable for the duration of the experiment, however, ENO increased gradually from 1.3+/-0.7 to 17.6+/-3.1 ppb after 5 hrs (p< .05). In the LPS treated rats, MAP decreased in the first 30 mins and then remained stable for 5 hrs. The decrease in MAP was associated with a gradual increase in ENO, which was significant after 180 mins (58.9+/-16.6 ppb) and reached 95.3+/-27.5 ppb after 5 hrs (p< .05). LNA and AG prevented the increase in ENO after LPS to the level in the control group. AG caused a partial reversal of systemic hypotension, which lasted for the duration of the experiment. LNA reversed systemic hypotension almost completely but only transiently for 1 hr, and caused severe metabolic acidosis in all animals. The co-administration of NO with AG had no added benefits on MAP and pH. In contrast, NO inhalation increased the duration of the reversal in MAP after LNA, alleviated the degree of acidosis, and decreased the mortality rate (from 55% to 29%). CONCLUSIONS In this animal model, LPS-induced hypotension was alleviated slightly and durably after AG, but only transiently after LNA. Furthermore, co-administration of NO with AG had no added benefits but alleviated the severity of metabolic acidosis and mortality after LNA. We conclude that nitric oxide synthase (NOS) inhibitors, given as a single large bolus in the early phase of sepsis, can exhibit some beneficial effects. Administration of inhaled NO with NOS inhibitors provided more benefits in some conditions and therefore may be a useful therapeutic combination in sepsis. NO production in sepsis does not seem to be a primary cause of systemic hypotension. Other factors are likely to have a major role.

UPDATE IN PULMONARY MEDICINE

Chronic inflammation in many pulmonary diseases, such as sarcoidosis and IPF, lead to end-stage lung disease and fibrosis. In other diseases, such as chronic thromboembolic disease and emphysema, long-term complications can result in pulmonary hypertension and cor pulmonale. Therapeutic options for end-stage lung disease are quite limited. One possible solution is lung transplantation. Although fraught with potential serious complications, including infection, rejection, and death, lung transplantation may offer overall improvement in mortality rates and quality of life.