Hospital-Acquired Pneumonia in Critically Ill Patients

Study objectives: To identify, in patients experiencing hospital-acquired pneumonia (HAP), prognostic factors present at disease onset and build an algorithm capable of stratifying mortality risk upon HAP onset. Design: Observational cohort from January 1994 to December 2001. Setting: One intensive care unit (ICU) from a university-affiliated, urban teaching hospital. Patients: All consecutive patients exhibiting bacteriologically documented HAP either on ICU admission or during ICU stay. Interventions: Data collection and multivariate analysis using Chi-Square Automatic Interaction and Detection technique. Results: 168 patients were studied. The overall mean mortality rate was 49.4%. Upon onset of HAP, five independent variables allowed binary stratification of mortality risk. These consisted of underlying diseases (nonfatal versus ultimately and rapidly fatal diseases), Simplified Acute Physiology Score II (less than versus ≥37), platelet count (less than versus ≥150 000/mm³), chest x-ray involvement (1 versus >1 lobe), and PaO₂/FiO₂ (less than versus ≥167mm Hg). A branching algorithm consisting of these five variables identified patients with HAP at both low (<35%) and high (>75%) risk of mortality. Conclusion: Mortality in ICU patients with HAP may be predicted early, upon onset of HAP, by the cumulative use of prognostic factors in an algorithm.     

Airway Management in Critically Ill Patients

In critically ill patients, endotracheal intubation is associated with a high risk of complications, including severe hypoxemia and hypotension. The purpose of this review is to discuss the definitions, complications, airway assessment, and patient optimization with respect to these patients. In addition, we present different approaches and techniques to help secure the airway in critically ill patients. We also discuss strategies to help minimize the risk of a difficult or failed airway and to mitigate the severe life-threatening complications associated with this high-risk procedure.     

Pepsin and Bile Acid Concentrations in Sputum of Mustard Gas Exposed Patients

Background/Aim:

Gastro-esophageal reflux has been suggested to be associated with several pulmonary complications such as asthma, and post-transplant bronchiolitis obliterans (BO). Pepsin or bile salts in the sputum is shown to be an optimal molecular marker of gastric contents macro/micro aspiration. In this study, we investigated sputum pepsin as a marker of micro-aspiration in sulfur mustard (SM) exposed cases compared to healthy controls.

Materials and Methods:

In a case controlled study, 26 cases with BO and 12 matched healthy controls were recruited and all cases were symptomatic and their exposure to SM was previously documented during Iran-Iraq conflict. Pepsin levels in sputum and total bile acids were measured using enzymatic assay. The severity of respiratory disorder was categorized based upon the spirometric values.

Result:

The average concentration of pepsin in sputum was higher in the case group (0.29 ± 0.23) compared with healthy subjects (0.13 ± 0.07; P ± 0.003). Moreover, the average concentration of bile acids in the sputum cases was not significantly different in comparison to the controls (P = 0.5).

Conclusion:

Higher pepsin concentrations in sputum of SM exposed patients compared with healthy control subjects indicate the occurrence of significantly more gastric micro-aspiration in SM exposed patients.     

Challenges in Glycemic Control in Perioperative and Critically Ill Patients: An Overview of Hypoglycemia in the Critically Ill

Hypoglycemia is a common and serious problem among patients with diabetes mellitus. It is also perceived as the most important obstacle to tight glucose control using intensive insulin therapy in critically ill patients. Because glucose is an obligatory metabolic fuel for the brain, hypoglycemia always represents an emergency that signals the inability of the brain to meet its energy needs. When left untreated, hypoglycemia can result in permanent brain damage and ultimately, death. In the context of critical illness that limits endogenous glucose production and increases glucose utilization, inadequate nutrition, or insufficient provision of glucose, intensive insulin therapy is the most frequent cause of hypoglycemia. Neurogenic and neuroglycopenic symptoms of hypoglycemia can remain unknown because of the underlying critical illness and sedation. Thus, close and reliable monitoring of the glycemic level is crucial in detecting hypoglycemia. In prospective randomized controlled studies comparing the effects of two glucose regimens, intensive insulin therapy aimed to reach strict glucose control (<110 mg/dl) but increased the incidence of severe hypoglycemia (<40 mg/dl) by four- to sixfold. Severe hypoglycemia is statistically associated with adverse outcomes in intensive care unit patients, although a direct causal relationship has not been demonstrated.     

Plasma Catalytic Iron,AKI, and Death among Critically Ill Patients

Background and objectives

Catalytic iron has been hypothesized to be a key mediator of AKI. However, the association between plasma catalytic iron levels and AKI has not been well studied in humans.

Design, settings, participants, & measurements

A single-center, prospective, nonconsecutive cohort study of 121 critically ill patients admitted to intensive care units (ICUs) between 2008 and 2012 was performed. Plasma catalytic iron, free hemoglobin, and other iron markers were measured on ICU days 1 and 4. The primary end point was in-hospital mortality or AKI requiring RRT. Secondary end points included mortality (assessed during hospitalization, at 30 days, and 1 year) and incident AKI, defined by modified Kidney Disease Improving Global Outcomes criteria.

Results

ICU day 1 plasma catalytic iron levels were higher among patients who reached the primary end point (median, 0.74 µmol/l [interquartile range, 0.31–3.65] versus 0.29 µmol/l [0.22–0.46]; P<0.01). ICU day 1 plasma catalytic iron levels were associated with number of packed red blood cell transfusions before ICU arrival (r_s=0.29; P<0.001) and plasma free hemoglobin levels on ICU day 1 (r_s=0.32; P<0.001). Plasma catalytic iron levels on ICU day 1 were significantly associated with in-hospital mortality or AKI requiring RRT, even after adjusting for age, enrollment eGFR, and number of packed red blood cell transfusions before ICU arrival (13 events; adjusted odds ratio per 1-SD higher ln[catalytic iron], 3.33; 95% confidence interval, 1.79 to 6.20). ICU day 1 plasma catalytic iron levels were also significantly associated with incident AKI, RRT, hospital mortality, and 30-day mortality.

Conclusions

Among critically ill patients, elevated plasma catalytic iron levels on arrival to the ICU are associated with a greater risk of incident AKI, RRT, and hospital mortality.     

Bile Acid Concentrations, Cytotoxicity, and pH of Fecal Water from Patients with Colorectal Adenomas

In the multistage model of human colorectaltumorigenesis, both genetic and environmental factorsplay an important role. The identity of theenvironmental factors involved, however, still remainsto be elucidated. As fecal bile acids are proposed ascandidates, we compared the concentration of bile acidsin fecal water from patients at different risk ofdeveloping colorectal cancer. In addition, pH of fecal water as well as its cytotoxicity toHT-29 colonic cells was determined. The high-risk groupconsisted of individuals diagnosed with one or more(tubulo)villous colorectal adenomas larger than 1 cm in diameter and containing moderate or severedysplasia (N = 20). Subjects with colorectal adenomassmaller than 1 cm and showing only minor dysplasia wereassigned to the medium risk group (N = 19). The control group consisted of persons with normalfindings by colonoscopy (N = 25). The results show nosignificant differences in fecal water bile acidconcentrations between the three groups. However, 46% of the observed cytotoxicity is explained in aregression model that includes pH and the concentrationsof deoxycholic acid, cholic acid, and ursodeoxycholicacid. The pH of fecal water is found to be significantly lower in the high risk group as compared to thecontrols, suggesting that a relatively high fecal pH hasa protective effect on the development of colorectaladenomas. Although hyperproliferation as a result of cytotoxicity has been suggested tocontribute to tumor formation in the colon, thepH-dependent cytotoxicity of bile acids in fecal waterwas not found to be associated with adenoma formation inthe present study.     

Challenges in Glycemic Control in Perioperative and Critically Ill Patients: Glycemic Variability and Mortality in Critically Ill Patients: The Impact of Diabetes

Background

Glycemic variability (GV) has recently been associated with mortality in critically ill patients. The impact of diabetes or its absence on GV as a risk factor for mortality is unknown.

Methods

A total of 4084 adult intensive care unit (ICU) patients admitted between October 15, 1999, and June 30, 2009, with at least three central laboratory measurements of venous glucose samples during ICU stay were studied retrospectively. The patients were analyzed according to treatment era and presence or absence of diabetes: 1460 admitted before February 1, 2003, when there was no specific treatment protocol for hyperglycemia (“PRE”) and 2624 patients admitted after a glycemic control protocol was instituted (“GC”). 3142 were patients without diabetes (“NON”), and 942 were patients with diabetes (“DM”). The coefficient of variation (CV) [standard deviation (SD)/mean glucose level (MGL)] of each patient was used as a measure of GV. Patients were grouped by MGL (mg/dl) during ICU stay (70–99, 100–119, 120–139, 140–179, and 180+) as well as by CV (<15%, 15–30%, 30–50%, and 50%+).

Results

Patients with diabetes had higher MGL, SD, and CV than did NON (p < .0001 for all comparisons). Mean glucose level was lower among both GC groups compared to their corresponding PRE groups (p < .0001), but CV did not change significantly between eras. Multivariable logistic regression analysis demonstrated that low CV was independently associated with decreased risk of mortality and high CV was independently associated with increased risk of mortality among NON PRE and GC patients, even after exclusion of patients with severe (<40 mg/dl) or moderate (40–59 mg/dl) hypoglycemia. There was no association between CV and mortality among DM using the same multivariable model. Mortality among NON from the entire cohort, with MGL 70–99 mg/dl during ICU stay, was 10.2% for patients with CV < 15% versus 58.3% for those with CV 50%+; for NON with MGL 100–119 mg/dl, corresponding rates were 10.6% and 55.6%.

Conclusions

Low GV during ICU stay was associated with increased survival among NON, and high GV was associated with increased mortality, even after adjustment for severity of illness. There was no independent association of GV with mortality among DM. Attempts to minimize GV may have a significant beneficial impact on outcomes of critically ill patients without diabetes.     

Emerging Applications of Extracardiac Ultrasound in Critically Ill Cardiac Patients

Point-of-care ultrasound has evolved as an invaluable diagnostic modality and procedural guidance tool in the care of critically ill cardiac patients. Beyond focused cardiac ultrasound, additional extracardiac ultrasound modalities may provide important information at the bedside. In addition to new uses of existing modalities, such as pulsed-wave Doppler ultrasound, the development of new applications is fostered by the implementation of additional features in mid-range ultrasound machines commonly acquired for intensive care units, such as tissue elastography, speckle tracking, and contrast-enhanced ultrasound quantification software. This review explores several areas in which ultrasound imaging technology may transform care in the future. First, we review how lung ultrasound in mechanically ventilated patients can enable the personalization of ventilator parameters and help to liberate them from mechanical ventilation. Second, we review the role of venous Doppler in the assessment of organ congestion and how tissue elastography may complement this application. Finally, we explore how contrast-enhanced ultrasound could be used to assess changes in organ perfusion.     

Renal Outcomes in Critically Ill Patients Receiving Propofol or Midazolam

Background and objectives

Propofol has been shown to provide protection against renal ischemia/reperfusion injury experimentally, but clinical evidence is limited to patients undergoing cardiac surgery. There are no data about its association with oliguria and AKI in critically ill patients.

Design, setting, participants, & measurements

We obtained data from the Multiparameter Intelligent Monitoring in Intensive Care II database (2001–2008). Patient selection criteria included adult patients in their first intensive care unit (ICU) admission, need for mechanical ventilation, and treatment with propofol or midazolam. Propensity score analysis (1:1) was used and renal-related outcomes (AKI, oliguria, cumulative fluid balance, and need for RRT) were evaluated during the first 7 days of ICU stay.

Results

There were 1396 propofol/midazolam-matched patients. AKI in the first 7-day ICU time period was statistically lower in propofol-treated patients compared with midazolam-treated patients (55.0% versus 67.3%, P<0.001). Propofol was associated with lower AKI incidence using both urine output (45.0% versus 55.7%, P<0.001) and serum creatinine criteria (28.8% versus 37.2%, P=0.001). Patients receiving propofol had oliguria (<400 ml/d) less frequently (12.4% versus 19.6%, P=0.001) and had diuretics prescribed less often (8.5% versus 14.3%, P=0.001). In addition, during the first 7 days of ICU stay, patients receiving propofol less frequently achieved cumulative fluid balance >5% of body weight (50.1% versus 58.3%, P=0.01). The need for RRT in the first 7 days of ICU stay was also less frequent in propofol-treated patients (3.4% versus 5.9%, P=0.03). ICU mortality was lower in propofol-treated patients (14.6% versus 29.7%, P<0.001).

Conclusions

In this large, propensity-matched ICU population, patients treated with propofol had a lower risk of AKI, fluid-related complications, and need for RRT.