Lung ultrasound is increasingly used in emergency departments, medical wards, and critical care units—adult, pediatric, and neonatal. In vitro and in vivo studies show that the number and type of artifacts visualized change with lung density. This has led to the idea of a quantitative lung ultrasound approach, opening up new prospects for use not only as a diagnostic but also as a monitoring tool. Consequently, the multiple scoring systems proposed in the last few years have different technical approaches and specific clinical indications, adaptable for more or less time-dependent patients. However, multiple scoring systems may generate confusion among physicians aiming at introducing lung ultrasound in their clinical practice. This review describes the various lung ultrasound scoring systems and aims to clarify their use in different settings, focusing on technical aspects, validation with reference techniques, and clinical applications.

In the intensive care unit, patient lung ultrasound provides accurate information on lung morphology with diagnostic and therapeutic relevance. It enables clinicians easy, rapid, and reliable evaluation of lung aeration and its variations at the bedside. Supplemental Digital Content is available in the text.

Background: Few outcome data are available about intraoperative cardiac arrest (IOCA). The authors studied 90-day functional outcomes and their determinants in patients admitted to the intensive care unit after IOCA. Methods: Patients admitted to 11 intensive care units in a period of 2000–2013 were studied retrospectively. The main outcome measure was a day-90 Cerebral Performance Category score of 1 or 2. Results: Of the 140 patients (61 women and 79 men; median age, 60 yr [interquartile range, 46 to 70]), 131 patients (93.6%) had general anesthesia, 80 patients (57.1%) had emergent surgery, and 73 patients (52.1%) had IOCA during surgery. First recorded rhythms were asystole in 73 patients (52.1%), pulseless electrical activity in 44 patients (31.4%), and ventricular fibrillation/ventricular tachycardia in 23 patients (16.4%). Median times from collapse to cardiopulmonary resuscitation and return of spontaneous circulation were 0 min (0 to 0) and 10 min (5 to 20), respectively. Postcardiac arrest shock was identified in 114 patients (81.4%). Main causes of IOCA were preoperative complications (n = 46, 32.9%), complications of anesthesia (n = 39, 27.9%), and complications of surgical procedures (n = 36, 25.7%). On day 90, 63 patients (45.3%) were alive with Cerebral Performance Category score 1/2. Independent predictors of day-90 Cerebral Performance Category score 1/2 were day-1 Logistic Organ Dysfunction score (odds ratio, 0.78 per point; 95% CI, 0.71 to 0.87; P = 0.0001), ventricular fibrillation/tachycardia as first recorded rhythm (odds ratio, 4.78; 95% CI, 1.38 to 16.53; P = 0.013), and no epinephrine therapy during postcardiac arrest syndrome (odds ratio, 3.14; 95% CI, 1.29 to 7.65; P = 0.012 ). Conclusions: By day 90, 45% of IOCA survivors had good functional outcomes. The main outcome predictors were directly related to IOCA occurrence and postcardiac arrest syndrome; they suggest that the intensive care unit management of postcardiac arrest syndrome may be amenable to improvement.

The aim of this review is to perform a critical analysis of experimental studies on aerosolized antibiotics and draw lessons for clinical use in patients with ventilator-associated pneumonia. Ultrasonic or vibrating plate nebulizers should be preferred to jet nebulizers. During the nebulization period, specific ventilator settings aimed at decreasing flow turbulence should be used, and discoordination with the ventilator should be avoided. The appropriate dose of aerosolized antibiotic can be determined as the intravenous dose plus extrapulmonary deposition. If these conditions are strictly respected, then high lung tissue deposition associated with rapid and efficient bacterial killing can be expected. For aerosolized aminoglycosides and cephalosporins, a decrease in systemic exposure leading to reduced toxicity is not proven by experimental studies. Aerosolized colistin, however, does not easily cross the alveolar-capillary membrane even in the presence of severe lung infection, and high doses can be delivered by nebulization without significant systemic exposure.

Background In spontaneously breathing cardiac patients, pulmonary artery pressure (PAP) can be accurately estimated from the transthoracic Doppler study of pulmonary artery and tricuspid regurgitation blood flows. In critically ill patients on mechanical ventilation for acute lung injury, the interposition of gas between the probe and the heart renders the transthoracic approach problematic. This study was aimed at determining whether the transesophageal approach could offer an alternative. Methods Fifty-one consecutive sedated and ventilated patients with severe hypoxemia (arterial oxygen tension/fraction of inspired oxygen < 300) were prospectively studied. Mean PAP measured from the pulmonary artery catheter was compared with several indices characterizing pulmonary artery blood flow assessed using transesophageal echocardiography: preejection time, acceleration time, ejection duration, preejection time on ejection duration ratio, and acceleration time on ejection duration ratio. In a subgroup of 20 patients, systolic PAP measured from the pulmonary artery catheter immediately before withdrawal was compared with Doppler study of regurgitation tricuspid flow performed immediately after pulmonary artery catheter withdrawal using either the transthoracic or the transesophageal approach. Results Weak and clinically irrelevant correlations were found between mean PAP and indices of pulmonary artery flow. A statistically significant and clinically relevant correlation was found between systolic PAP and regurgitation tricuspid flow. In 3 patients (14%), pulmonary artery pressure could not be assessed echocardiographically. Conclusions In hypoxemic patients on mechanical ventilation, mean PAP cannot be reliably estimated from indices characterizing pulmonary artery blood flow. Systolic PAP can be estimated from regurgitation tricuspid flow using either transthoracic or transesophageal approach.

Background Malposition of percutaneously inserted chest tubes is considered as a rare complication in critically ill patients. Its incidence, however, remains uncertain. The aims of the study were to assess the true incidence of chest tube malposition in critically ill patients and to identify predicting factors. Methods The authors prospectively studied 122 chest tubes percutaneously inserted in 75 consecutive critically ill patients. For clinical reasons independent of the study, thoracic computed tomography scanning was performed in 63 patients, allowing direct visualization of 106 chest tubes. Based on these findings, chest tube position was classified as intrapleural, intrafissural, or intraparenchymal. Factors predicting chest tube malposition were analyzed by univariate and multivariate analysis. Results The mean delay between chest tube placement and thoracic scan was 3.5+/-2.9 days. Twenty-two chest tubes were diagnosed as being intrafissural (21%), and 10 were diagnosed as being intraparenchymal (9%). The only predicting factor associated with the risk of malposition was the use of a trocar for the percutaneous insertion of the chest tube (P=0.032). Conclusions Malposition was detected in 30% of percutaneously inserted chest tubes, a higher incidence than previously reported. Avoiding the use of a trocar may reduce significantly the incidence of chest tube malposition.

Background In cardiac patients, pulmonary capillary wedge pressure (PCWP) is estimated using color M-mode Doppler study of left ventricular filling and Doppler tissue imaging. The goal of this study was to assess whether echocardiography accurately estimates PCWP in critically ill patients. Methods Sixty ventilated patients admitted for septic shock and acute lung injury were prospectively studied using simultaneously transesophageal echocardiography and pulmonary artery catheterization. Initial PCWP values and their changes measured invasively were compared to initial values and corresponding changes of early diastolic velocity of mitral annulus displacement measured by Doppler tissue imaging (Ea), flow propagation velocity of early diastolic mitral inflow measured by color M-mode Doppler (Vp), and their respective ratio to early mitral inflow velocity (E) measured by conventional Doppler: E/Ea and E/Vp. Relations between E/Ea, E/Vp, and PCWP were prospectively tested in 20 additional patients. Results E/Ea and E/Vp gave a rough estimate of initial PCWP values with mean biases of 0.4 +/- 2.2 and 0.1 +/- 2.9 mmHg, respectively. Receiving operating characteristic curves demonstrated that an E/Ea of 6 or greater is an accurate predictor of a PCWP of 13 mmHg or greater and that an E/Ea of 5.4 is a good predictor of a PCWP of 8 mmHg or less. Changes in PCWP were significantly correlated to changes in E/Ea (Rho = 0.84, P < 0.0001). Conclusions In patients with postoperative circulatory shock and acute lung injury, transesophageal echocardiography estimates noninvasively PCWP. However, echocardiographic estimation of PCWP may not be accurate enough for adjusting therapy.

Background Although neonatal rats have become widely used as experimental laboratory animals, minimum alveolar concentration (MAC) values of volatile anesthetics in rats during postnatal maturation remain unknown. Methods We determined MAC values of volatile anesthetics in spontaneously breathing neonatal (2-, 9-, and 30-day-old) and adult Wistar rats exposed to increasing (in 0.1-0.2% steps) concentrations of halothane, isoflurane, or sevoflurane (n = 12-20 in each group), using the tail-clamp technique. MAC and its 95% confidence intervals were calculated using logistic regression and corrected for body temperature (37 degrees C). Results In adult rats, inspired MAC values corrected at 37 degrees C were as follows: halothane, 0.88% (confidence interval, 0.82-0.93%); isoflurane, 1.12% (1.07-1.18%); and sevoflurane, 1.97% (1.84-2.10%). In 30-day-old rats, the values were as follows: halothane, 1.14% (1.07-1.20%); isoflurane, 1.67% (1.58-1.76%); and sevoflurane, 2.95% (2.75-3.15%). In 9-day-old rats, inspired MAC values were as follows: halothane, 1.68% (1.58-1.78%); isoflurane, 2.34% (2.21-2.47%); and sevoflurane, 3.74% (3.64-3.86%). In 2-day-old rats, inspired MAC values were as follows: halothane, 1.54% (1.44-1.64%); isoflurane, 1.86% (1.72-2.01%); and sevoflurane, 3.28% (3.09-3.47%). Conclusion As postnatal age increases, MAC value significantly increases, reaching the greatest value in 9-day-old rats, and decreases thereafter, and at 30 days is still greater than the adult MAC value.