Sedation in critically ill patients: a review.

The most commonly used sedatives in the intensive care setting are midazolam, propofol and lorazepam. The ACCM/SCCM recommendations provide reasonable options for selection of therapeutic agents. Choices may differ, however, in specific cases. For example, where frequent neurological evaluation is necessary, propofol may be the sedative of choice in long term sedation. Abrupt withdrawal of any sedative may precipitate withdrawal symptoms and infusion dosages should be reduced gradually. Finally, any sedation strategy should be devised in cooperation with the ICU nursing staff to be certain that both medical and nursing requirements converge with the patients needs.

A 9-year, single-institution, retrospective review of death rate and prognostic factors in adult respiratory distress syndrome.

OBJECTIVE: To evaluate, at a single institution, the adult respiratory distress syndrome (ARDS) death rate in critically ill ventilated surgical/trauma patients and to identify the factors predicting death in these patients. SUMMARY BACKGROUND DATA: The prognostic features affecting mortality at the onset of ARDS have not been clearly defined. Defining rare characteristics would be valuable because it would allow for better stratification of patients in clinical trials and more appropriate utilization of constrained resources in ICU environments. METHODS: A retrospective analysis of 980 ventilated surgical and trauma intensive care unit patients from January 1990 to December 1998 was performed at Rhode Island Hospital. One hundred eleven adult intensive care unit patients with ARDS were identified using the criteria of Lung Injury Score more than 2.50 and the definition from the American-European Consensus Conference. Slightly more than half were trauma patients, 57% were men, and the median age was 59 years. The overall death rate was 52%. Patients were segregated by admission date to the intensive care unit (before or after January 1, 1995). Severity of illness was measured by the Revised Trauma Score for trauma patients and the Acute Physiology and Chronic Health Evaluation III for surgical patients. The Multiple Organ Dysfunction Score was determined on the day of onset of ARDS for all patients. Other recorded variables were age, sex, intensive care unit length of stay, length and mode of ventilation, presence or absence of tracheostomy, ventilation variables of peak and mean airway pressures, lung injury scores, elective versus emergency surgery, and presence or absence of pneumonia. RESULTS: There was a significant decrease in the ARDS death rate from the period 1990 to 1994 to the period 1995 to 1998. The major reason for the decline was a reduction in the posttraumatic ARDS death rate. Lung-protective ventilation strategies were used more frequently in the second period than in the first, and the death rate was significantly decreased in trauma patients in the second period when lung-protective ventilation modes were used. Predictors of death at the onset of ARDS were advanced age, Multiple Organ Dysfunction Score of 8 or more, and Lung Injury Score of 2.76 or more. CONCLUSION: In this single-institution series, the death rate from ARDS declined from 1990 to 1998, primarily in posttraumatic patients, and the decrease is related to the use of lung-protective ventilation strategies. Based on this patient population, the authors developed a statistical model to evaluate important prognostic indicators (advanced age, organ system and pulmonary dysfunction measurements) at the onset of ARDS.

Prediction of post-extubation work of breathing.

OBJECTIVE: To evaluate which mode of preextubation ventilatory support most closely approximates the work of breathing performed by spontaneously breathing patients after extubation. DESIGN: Prospective observational design. SETTING: Medical, surgical, and coronary intensive care units in a university hospital. PATIENTS: A total of 22 intubated subjects were recruited when weaned and ready for extubation. INTERVENTIONS: Subjects were ventilated with continuous positive airway pressure at 5 cm H2O, spontaneous ventilation through an endotracheal tube (T piece), and pressure support ventilation at 5 cm H2O in randomized order for 15 mins each. At the end of each interval, we measured pulmonary mechanics including work of breathing reported as work per liter of ventilation, respiratory rate, tidal volume, negative change in esophageal pressure, pressure time product, and the airway occlusion pressure 100 msec after the onset of inspiratory flow, by using a microprocessor-based monitor. Subsequently, subjects were extubated, and measurements of pulmonary mechanics were repeated 15 and 60 mins after extubation. MEASUREMENTS AND MAIN RESULTS: There were no statistical differences between work per liter of ventilation measured during continuous positive airway pressure, T piece, or pressure support ventilation (1.17+/-0.67 joule/L, 1.11+/-0.57 joule/L, and 0.97+/-0.57 joule/L, respectively). However, work per liter of ventilation during all three preextubation modes was significantly lower than work measured 15 and 60 mins after extubation (p < .05). Tidal volume during pressure support ventilation and continuous positive airway pressure (0.46+/-0.11 L and 0.44+/-0.11 L, respectively) were significantly greater than tidal volume during both T-piece breathing and spontaneous breathing 15 mins after extubation (p < .05). Negative change in esophageal pressure, the airway occlusion pressure 100 msec after the onset of inspiratory flow, and pressure time product were significantly higher after extubation than during any of the three preextubation modes (p < .05). CONCLUSIONS: Work per liter of ventilation, negative change in esophageal pressure, the airway occlusion pressure 100 msec after the onset of inspiratory flow, and pressure time product all significantly increase postextubation. Tidal volume during continuous positive airway pressure or pressure support ventilation overestimates postextubation tidal volume.

Analysis of the effect of conversion from open to closed surgical intensive care unit.

OBJECTIVE: To compare the effect on clinical outcome of changing a surgical intensive care unit from an open to a closed unit. DESIGN: The study was carried out at a surgical intensive care unit in a large tertiary care hospital, which was changed on January 1, 1996, from an open unit, where private attending physicians contributed and controlled the care of their patients, to a closed unit, where patients' medical care was provided only by the surgical critical care team (ABS or ABA board-certified intensivists). A retrospective review was undertaken over 6 consecutive months in each system, encompassing 274 patients (125 in the open-unit period, 149 in the closed-unit period). Morbidity and mortality were compared between the two periods, along with length-of-stay (LOS) and number of consults obtained. A set of independent variables was also evaluated, including age, gender, APACHE III scores, the presence of preexisting medical conditions, the use of invasive monitoring (Swan-Ganz catheters, central and arterial lines), and the use of antibiotics, low-dose dopamine (LDD) for renal protection, vasopressors, TPN, and enteral feeding. RESULTS: Mortality (14.4% vs. 6.04%, p = 0.012) and the overall complication rate (55.84% vs. 44.14%, p = 0.002) were higher in the open-unit group versus the closed-unit group, respectively. The number of consults obtained was decreased (0.6 vs. 0.4 per patient, p = 0.036), and the rate of occurrence of renal failure was higher in the open-unit group (12.8% vs. 2.67%, p = 0.001). The mean age of the patients was similar in both groups (66.48 years vs. 66.40, p = 0.96). APACHE III scores were slightly higher in the open-unit group but did not reach statistical significance (39.02 vs. 36.16, p = 0.222). There were more men in the first group (63.2% vs. 51.3%). The use of Swan-Ganz catheters or central and arterial lines were identical, as was the use of antibiotics, TPN, and enteral feedings. The use of LDD was higher in the first group, but the LOS was identical. CONCLUSIONS: Conversion of a tertiary care surgical intensive care unit from an open to closed environment reduced dopamine usage and overall complication and mortality rates. These results support the concept that, when possible, patients in surgical intensive care units should be managed by board-certified intensivists in a closed environment.

Typhoid fever associated with adult respiratory distress syndrome.

Adult respiratory distress syndrome (ARDS) is rarely reported in association with typhoid fever despite the fact that sepsis is a common manifestation and endotoxemia has been described in this multisystem condition. We describe the course of a patient with ARDS and typhoid fever. With conventional treatment of the lung injury and with specific antimicrobial therapy, the patient survived. Recent consensus definitions of sepsis and ARDS simplified reporting of this case. Clinicians caring for individuals from or recent visitors to developing countries should be aware of the association of typhoid fever, sepsis, and ARDS.

Effects of cigarette smoking and short-term smoking cessation on airway responsiveness to inhaled methacholine.

Threshold of airway responsiveness to methacholine aerosol was determined in 53 apparently healthy persons. In 18 nonallergic nonsmokers matched according to sex and age to 18 nonallergic smokers, the mean methacholine threshold of airway response (T), as measured using partial flow-volume curves, had a tendency to be greater in nonsmokers, but the difference was not significant for the group as a whole; it was, however, significant for a subset of 9 matched pairs with a cigarette consumption greater than 10 pack-years (mean T nonsmokers, 2.8 mg/ml; smokers, 0.3; p = 0.036). In 17 smokers who stopped smoking for 99 days in average, T was not significantly different for the group as a whole, although the majority of the smokers reported improvement of respiratory symptoms after cessation of smoking. The results of this study indicate that cigarette smoking is associated with increased airways responsiveness to inhaled methacholine and that this effect is dose related.

Combined effect of cigarette smoking and allergic rhinitis on airway responsiveness to inhaled methacholine.

A group of healthy nonatopic subjects was compared with a group of atopic subjects with allergic rhinitis who were otherwise healthy. They were matched for sex, age, and smoking habits; 15 pairs were nonsmokers and 11 pairs were smokers. Threshold of airway response to inhaled methacholine based on partial flow-volume curves was not significantly different between nonatopic nonsmokers and nonsmokers with allergic rhinitis. However, smokers with allergic rhinitis had a threshold on the average of 3 doubling doses lower than smokers without allergic rhinitis. We concluded that there is a combined effect of chronic cigarette smoking and allergic rhinitis affecting nonspecific airway responsiveness.