Electricity: How Much for the Contemporary Tertiary Care Operating Room? A Case Report.

Surgery requires many electrically driven devices. Three events occurred recently in an operating room (OR) suite circa the 1980s wherein circuit breakers tripped due to overloaded circuits. This led to us to (1) increase OR electric capacity; (2) record each instrument's power requirements, map their OR location, and determine when during surgery they were used; (3) provide users with instruction and diagrams into which outlet to plug each instrument. When introducing surgeries requiring devices, especially with high electrical power (current or amperage) demands, or renovating older or planning new ORs, it is important to provide ORs with sufficient electric current, circuits, and outlets.

Urine flow rate monitoring in hypovolemic multiple trauma patients.

BACKGROUND: The urine output is an important clinical parameter of renal function and blood volume status, especially in critically ill multiple trauma patients. In the present study, the minute-to-minute urine flow rate and its variability were analyzed in hypotensive multiple trauma patients during the first 6 h of their ICU (intensive care unit) stay. These parameters have not been previously reported. METHODS: The study was retrospective and observational. Demographic and clinical data were extracted from the computerized Register Information Systems. A total of 59 patients were included in the study. The patients were divided into two study groups. Group 1 consisted of 29 multiple trauma patients whose systolic blood pressure was greater than 90 mmHg on admission to the ICU and who were consequently deemed to be hemodynamically compromised. Group 2 consisted of 30 patients whose systolic blood pressure was less than 90 mmHg on admission to the ICU and who were therefore regarded as hemodynamically uncompromised. RESULTS: The urine output and urine flow rate variability during the first 6 h of the patients' ICU stay was significantly lower in group 2 than in group 1 (p < 0.001 and 0.006 respectively). Statistical analysis by the Pearson method demonstrated a strong direct correlation between decreased urine flow rate variability and decreased urine output per hour (R = 0.17; P = 0.009), decreased mean arterial blood pressure (R = 0.24; p = 0.001), and increased heart rate (R = 0.205; p = 0.001). CONCLUSION: These findings suggest that minute-to-minute urine flow rate variability is a reliable incipient marker of hypovolemia and that it should therefore take its place among the parameters used to monitor the hemodynamic status of critically ill multiple trauma patients.

Minute-to-minute urine flow rate variability: a new renal physiology variable.

BACKGROUND: Urine output is a surrogate for tissue perfusion and is typically measured at 1-hour intervals. Because small urine volumes are difficult to measure in urine collection bags, considerable over- or underestimation is common. To overcome these shortcomings, digital urine meters were developed. Because these monitors measure urine volume in 1-minute intervals, they provide minute-to-minute measurements of the urine flow rate (UFR). In a previous study, we observed that the minute-to-minute variability in the UFR disappeared during hypovolemia. The aim of this study was to describe the minute-to-minute variability in the UFR as a new physiological variable and to show its relationship to blood volume depletion. METHODS: Seven adult pigs were used in this study. The UFR, minute-to-minute UFR, mean arterial blood pressure, heart rate, and base excess were measured at euvolemia and during gradual hemorrhaging (10%, 20%, and 30% of estimated blood volume). Variance and wavelet spectral analysis were used to measure the disappearance of the minute-to-minute UFR variability. RESULTS: The UFR decreased from 2.2 ± 0.2 to 1.0 ± 0.1 mL/min after a 10% estimated blood volume loss (±1 SE, n = 7, P = 0.0348). The variance in the minute-to-minute UFR decreased from 1.4 ± 0.3 to 0.4 ± 0.1 mL/min (±1 SE, n = 7, P = 0.046). CONCLUSIONS: The UFR and its minute-to-minute variability decrease during hemorrhaging. The variability in the UFR may be useful as an aid for the diagnosis of hypovolemia.

The current status of continuous noninvasive measurement of total, carboxy, and methemoglobin concentration.

Intraoperative early detection of anemia, identifying toxic levels of carboxyhemoglobin after carbon monoxide exposure and titrating drug dosage to prevent toxic levels of methemoglobin are important goals. The pulse oximeter works by illuminating light into the tissue and sensing the amount of light absorbed. The same methodology is used by laboratory hemoglobinometers to measure hemoglobin concentration. Because both devices work in the same way, efforts were made to modify the pulse oximeter to also measure hemoglobin concentration. Currently there are 2 commercial pulse oximeters (Masimo Rainbow SET and OrSense NBM-200MP) that measure total hemoglobin concentration and one (Masimo) that also measures methemoglobin and carboxyhemoglobin. In this review, we describe the peer-reviewed literature addressing the accuracy of these monitors.

Automatic computerized endotracheal tube position verification: an animal model evaluation.

BACKGROUND: Improper endotracheal tube positioning carries a high risk for morbidity and mortality; verification and confirmation of correct placement is necessary. We propose a computer-automated identification of endotracheal tube positioning using image analysis. The end product will not retain a monitor; rather, the acquired image will be automatically analyzed by a mini electronic processor. METHODS: An algorithm that automatically analyzes images has been developed: it classifies images into esophagus, trachea, and carina. Image processing includes converting the image to grayscale and extracting and classifying into 1 class, on the basis of similarity to pretrained patterns. A prototypical video sensor mounted on an intubating stylet has also been assembled. This stylet was introduced into 10 bovine throats, and video images were gathered. Videos were analyzed and classified as carina, trachea, or esophagus. The videos were then introduced to the new algorithm. In each test cycle, 9 videos were used to train the algorithm, and the 10th was used as a benchmark. This procedure was repeated 10 times so that each video was used 9 times for teaching and 1 time for testing. RESULTS: Ten videos were recorded, of which 1600 images were extracted (trachea: 490 images; carina: 550 images; and esophagus: 560 images). Only 1 esophageal image was classified as trachea (false positive 0.001%). Two carinal images and 22 tracheal images were recognized as esophagus (false negative 0.041%), sensitivity 0.98 and specificity 0.99. Twenty images of the carina were identified as trachea, and 25 images of the trachea were identified as the carina (false positive 0.045%, false negative 0.041%, sensitivity 0.96 and specificity 0.95). CONCLUSION: A potential tube position verification system was assessed. High accuracy of the analysis algorithm was shown using nonperfused biological tissue, justifying further research.

Automatic endotracheal tube position confirmation system based on image classification--a preliminary assessment.

Endotracheal intubation is a complex medical procedure in which a ventilating tube is inserted into the human trachea. Improper positioning carries potentially fatal consequences and therefore confirmation of correct positioning is mandatory. This paper introduces a novel system for endotracheal tube position confirmation. The proposed system comprises a miniature complementary metal oxide silicon sensor (CMOS) attached to the tip of a semi rigid stylet and connected to a digital signal processor (DSP) with an integrated video acquisition component. Video signals are acquired and processed by a confirmation algorithm implemented on the processor. The confirmation approach is based on video image classification, i.e., identifying desired expected anatomical structures (upper trachea and main bifurcation of the trachea) and undesired structures (esophagus). The desired and undesired images are indicators of correct or incorrect endotracheal tube positioning. The proposed methodology is comprised of a continuous and probabilistic image representation scheme using Gaussian mixture models (GMMs), estimated using a greedy algorithm. A multi-dimensional feature space, which consists of several textural-based features, is utilized to represent the images. The performance of the proposed algorithm was evaluated using two datasets: a dataset of 1600 images extracted from 10 videos recorded during intubations on dead cows, and a dataset of 358 images extracted from 8 videos recorded during intubations performed on human subjects. Each one of the video images was classified by a medical expert into one of three categories: upper tracheal intubation, correct (carina) intubation and esophageal intubation. The results, obtained using a leave-one-case-out method, show that the system correctly classified 1530 out of 1600 (95.6%) of the cow intubations images, and 351 out of the 358 human images (98.0%). Misclassification of an image of the esophagus as carina or upper-trachea, which is potentially fatal, was extremely rare (only one case when in the animal dataset and no cases when in the human intubation dataset). The classification results of the cow intubations dataset compare favorably with a state-of-the-art classification method tested on the same dataset.

Urine flow is a novel hemodynamic monitoring tool for the detection of hypovolemia.

BACKGROUND: Noticeable changes in vital signs indicating hypovolemia occur only after 15% of the blood volume is lost. More sensitive variables (e.g., cardiac output, systolic pressure variation and its Δdown component) are invasive and difficult to obtain in the early phase of bleeding. Lately, a new technology for continuous optical measurements of minute-to-minute urine flow rates has become available. We performed a preliminary evaluation to determine whether urine flow can act as an early and sensitive warning of hypovolemia. METHODS: Eleven patients (ASA physical status I-II) undergoing posterior spine fusion surgery were studied prospectively. Study variables included heart rate, blood pressure (systolic and diastolic), systolic pressure variation and Δdown, minute urinary flow, hemoglobin, blood and urinary sodium, and creatinine in the blood and urine. Urine flow rate was measured using URINFO 2000™ (FlowSense Medical, Misgav, Israel). After recording baseline variables, 10 mL/kg of the patient's blood was shed and a second set of variables was recorded. Subsequently, hypovolemia was reversed by infusing colloid solution (hetastarch 6%) followed by recording a third set of variables. These 3 observations were then compared. RESULTS: An average of 614 ± 143 mL (mean ± SD) of blood was shed. During phlebotomy, the mean urine flow rate decreased from 5.7 ± 8 mL/min to 1.07 ± 2.5 mL/min. Systolic blood pressure and hemoglobin also decreased. Δdown increased. After rehydration, urine flow, blood pressure, and Δdown values returned to baseline. The hemoglobin concentration decreased whereas other variables did not change significantly. CONCLUSION: Urine flow rate is a dynamic variable that seems to be a reliable indicator of changes in blood volume. These results justify further investigation.

Novel automatic endotracheal position confirmation system: mannequin model algorithm evaluation.

OBJECTIVE: A novel endotracheal intubation accurate positioning confirmation system based on image classification algorithm is introduced and evaluated using a mannequin model. METHODS: The system comprises a miniature complementary metal oxide silicon sensor (CMOS) attached to the tip of a semi rigid stylet and connected to a digital signal processor (DSP) with an integrated video acquisition component. Video signals acquired and processed by an algorithm implemented on the processor. During mannequin intubations, video signals were continuously recorded. A total of 10 videos were recorded. From each video, 7 images of esophageal intubation and 8 images of endotracheal intubation (in which the carina could be clearly seen) were extracted, yielding a total of 150 images taken from arbitrary positions and angles which were processed by the confirmation algorithm. RESULTS: The performance of the confirmation algorithm was evaluated using a leave-one-out method: in each iteration, 149 images were used to train the system and estimate the models, and the remaining image was used to test the system. This process was repeated 150 times such that each image participated once in testing. The system correctly identified 80 out of 80 endotracheal intubations and 70 out of 70 esophageal intubations. CONCLUSIONS: This fully automatic image recognition system was used successfully to discriminate airway carina and non-carina endotracheal tube positioning. The system had a 100% success rate using a mannequin model and therefore further investigation including live tissue model and human research should follow.

Early management of the traumatized airway.

Penetrating face and neck trauma is usually obvious, but blunt trauma mandates high index of suspicion to recognize its existence. Comprehensive understanding of the injury is mandatory to plan the best timing and method to secure the airway.

Conventional terrorist bomb incidents and the intensive care unit.

PURPOSE OF REVIEW: A terror bombing creates a momentary stress on acute care services, including the emergency medical system, emergency departments, and intensive care units. A knowledge of the progression of events, the anticipated volume of injured survivors, and the pattern of injuries will enable the physician in the intensive care unit to prepare the unit quickly and efficiently for the expected rush of injured survivors. RECENT FINDINGS: In the past 2 years it has become apparent in the medical literature that terror bombing causes more complicated injuries than other types of trauma. The injuries are a combination of blast, penetrating, and blunt trauma, as well as burns. As a result, a significant number of patients will need care in the intensive care unit for a long time. Treating these injuries mandates an understanding of the combination of injury mechanisms because the ideal treatment for one mechanism might cause harm if another coexists. In addition, recent literature delineates the volume of admissions an intensive care unit should anticipate. This information should allow the preparation of sufficient vacant intensive care unit beds and facilitate the efficient use of equipment and personnel. SUMMARY: This review, based on recently published data, aims to provide the intensive care unit physician with crucial information about the anticipated progression of events, the possible numbers of patients, and the nature of their injuries after a terrorist bombing. This information should aid in rational crisis planning.

Multiple casualty terror events: the anesthesiologist's perspective.

UNLABELLED: In a 28-mo period 14 multiple-casualty terror events occurred in Jerusalem, challenging the Department of Anesthesiology and Critical Care Medicine of the city's sole Level 1 trauma center. We performed a retrospective review of the response of the department to evaluate staff activities, resource use (emergency department, operating rooms, and intensive care unit [ICU]), and patient flow. A total of 1062 people were injured in the 14 multi-casualty terror incidents. The emergency department treated 355 victims; 108 of them were hospitalized, and 58 underwent surgery during the first 8 h. Only two surgeries were performed during the first hour, and the average time to the first surgery was 124 min. Fifty-one patients were admitted to the ICU an average of 5.5 h after the terror event. After a terrorist act, multiple, simultaneous efforts were required of the anesthesiology department, including taking part in the initial resuscitation in the emergency department, anesthetizing victims for surgery and angiographies, and caring for them in the recovery room and ICU. Therefore, anesthesiology departments are greatly impacted by such events and must plan for them to maximize the use of available personnel and to have the appropriate equipment and supplies available. IMPLICATIONS: Anesthesiologists provide essential care to patients injured in terror events, from the initial resuscitation through therapeutic/diagnostic procedures and surgeries. Operational issues faced by a department of anesthesiology during the initial 8 h after terrorist actions were examined. Multiple, and often parallel, efforts were required of the department.