Optimization of the Operating Room Scheduling Process for Improving Efficiency in a Tertiary Hospital.

Efficient operating room (OR) scheduling can improve OR utilization and reduce costs. We hypothesize that the scheduling office (ORSO) leading the modification scheduling process could increase OR utilization rate. Using retrospective data from a single tertiary hospital in two consecutive calendar years, we compared OR utilization rate, the number of daily cases and cumulative operative time in the pre- and post-implementation of scheduling process alteration. We operated about 100,609 cases in the OR during the study period. Daytime utilization rate increased from 85.6% to 89.4% (P < 0.001); overall OR utilization rate from 115.1% to 117.6% (P = 0.019); daily case numbers from 229.9 ± 7.3 to 239.6 ± 7.6 (P = 0.0.14); and cumulative operation time of total and daytime cases from 611.7 case-hour/day to 624.5 case-hour/day (P = 0.013) and from 510.8 case-hour/day to 533.8 case-hour/day (P < 0.001), respectively. Evening/night time case-hour significantly decreased from 100.9 case-hour/day to 90.7 case-hour/day (P < 0.001). The optimization of the scheduling process and coordination by the office during regular workhours resulted in enhanced OR efficiency. The OR scheduling office can act as a control tower to make OR management more flexible, which can improve efficiency and carry financial benefits in tertiary hospitals.

Real-Time Monitoring of Blood Pressure Using Digitalized Pulse Arrival Time Calculation Technology for Prompt Detection of Sudden Hypertensive Episodes During Laryngeal Microsurgery: Retrospective Observational Study.

BACKGROUND: Laryngeal microsurgery (LMS) is often accompanied by a sudden increase in blood pressure (BP) during surgery because of stimulation around the larynx. This sudden change in the hemodynamic status is not immediately reflected in a casual cuff-type measurement that takes intermittent readings every 3 to 5 min. OBJECTIVE: This study aimed to investigate the potential of pulse arrival time (PAT) as a marker for a BP surge, which usually occurs in patients undergoing LMS. METHODS: Intermittent measurements of BP and electrocardiogram (ECG) and photoplethysmogram (PPG) signals were recorded during LMS. PAT was defined as the interval between the R-peak on the ECG and the maximum slope on the PPG. Mean PAT values before and after BP increase were compared. PPG-related parameters and the correlations between changes in these variables were calculated. RESULTS: BP surged because of laryngoscopic manipulation (mean systolic BP [SBP] from 115.3, SD 21.4 mmHg, to 159.9, SD 25.2 mmHg; P<.001), whereas PAT decreased significantly (from mean 460.6, SD 51.9 ms, to 405.8, SD 50.1 ms; P<.001) in most of the cases. The change in SBP showed a significant correlation with the inverse of the PAT (r=0.582; P<.001). Receiver-operating characteristic curve analysis indicated that an increase of 11.5% in the inverse of the PAT could detect a 40% increase in SBP, and the area under the curve was 0.814. CONCLUSIONS: During LMS, where invasive arterial catheterization is not always possible, PAT shows good correlation with SBP and may, therefore, have the potential to identify abrupt BP surges during laryngoscopic manipulations in a noninvasive manner.

Recurrent ST segment elevations in a patient with asymptomatic early repolarization during head and neck surgery: implications of vasospastic angina.

A 57-year-old woman scheduled for cochlear implant removal exhibited preoperative electrocardiographic findings of early repolarization (ER). Four episodes of transient ST segment elevations during surgery raised suspicion for vasospastic angina (VA). In the post-anesthetic care unit, the patient complained of chest discomfort and received sublingual nitroglycerin with uncertain effect. The patient refused to proceed with postoperative invasive coronary angiography, resulting in inconclusive diagnosis. Intraoperative circumstances limit the diagnosis of VA, which emphasizes the need for further testing to confirm the diagnosis. When VA is suspected in patients with underlying ER, it is reasonable to consider invasive examination to establish the diagnosis and prevent recurrence of VA. If ST changes are observed during surgery in patients with preoperative ER, careful monitoring is recommended. Due to general anesthesia, the absence of patient symptoms limits the definitive diagnosis of those with suspected VA. Therefore, additional postoperative surveillance is recommended.

Pulmonary aspiration during intubation in a high-risk patient: A video clip and clinical implications.

We report a case of pulmonary aspiration during induction of general anesthesia in a patient who was status post esophagectomy. Sudden, unexpected aspiration occurred even though the patient had fasted adequately (over 13 hours) and received rapid sequence anesthesia induction. Since during esophagectomy, the lower esophageal sphincter is excised, stomach vagal innervation is lost, and the stomach is flaccid, draining only by gravity, the patient becomes vulnerable to aspiration. As the incidence of perioperative pulmonary aspiration is relatively low, precautions to prevent aspiration tend to be overlooked. We present a video clip showing pulmonary aspiration and discuss the literature concerning the risk of aspiration and its preventive strategies.

Suppressed neural complexity during ketamine- and propofol-induced unconsciousness.

Ketamine and propofol have distinctively different molecular mechanisms of action and neurophysiological features, although both induce loss of consciousness. Therefore, identifying a common feature of ketamine- and propofol-induced unconsciousness would provide insight into the underlying mechanism of losing consciousness. In this study we search for a common feature by applying the concept of type-II complexity, and argue that neural complexity is essential for a brain to maintain consciousness. To test this hypothesis, we show that complexity is suppressed during loss of consciousness induced by ketamine or propofol. We analyzed the randomness (type-I complexity) and complexity (type-II complexity) of electroencephalogram (EEG) signals before and after bolus injection of ketamine or propofol. For the analysis, we use Mean Information Gain (MIG) and Fluctuation Complexity (FC), which are information-theory-based measures that quantify disorder and complexity of dynamics respectively. Both ketamine and propofol reduced the complexity of the EEG signal, but ketamine increased the randomness of the signal and propofol decreased it. The finding supports our claim and suggests EEG complexity as a candidate for a consciousness indicator.

Cardiovascular collapse due to right heart failure following ethanol sclerotherapy: a case report.

Ethanol sclerotherapy for the treatment of low-flow vascular malformations can cause catastrophic cardiopulmonary complications, including pulmonary embolism and pulmonary hypertension, that can result in right heart failure and fatal arrhythmias, leading to death. We here report a case of abrupt cardiovascular collapse that developed immediately following ethanol sclerotherapy in 31-year-old female patient who had a large arteriovenous malformation in her leg. Anesthesiologists should be aware of the fatal cardiopulmonary complications that are associated with ethanol sclerotherapy and consider the use of invasive hemodynamic monitoring, such as pulmonary artery pressure monitoring, when large doses of ethanol are required.

Preferential inhibition of frontal-to-parietal feedback connectivity is a neurophysiologic correlate of general anesthesia in surgical patients.

BACKGROUND: The precise mechanism and optimal measure of anesthetic-induced unconsciousness has yet to be elucidated. Preferential inhibition of feedback connectivity from frontal to parietal brain networks is one potential neurophysiologic correlate, but has only been demonstrated in animals or under limited conditions in healthy volunteers. METHODS AND FINDINGS: We recruited eighteen patients presenting for surgery under general anesthesia; electroencephalography of the frontal and parietal regions was acquired during (i) baseline consciousness, (ii) anesthetic induction with propofol or sevoflurane, (iii) general anesthesia, (iv) recovery of consciousness, and (v) post-recovery states. We used two measures of effective connectivity, evolutional map approach and symbolic transfer entropy, to analyze causal interactions of the frontal and parietal regions. The dominant feedback connectivity of the baseline conscious state was inhibited after anesthetic induction and during general anesthesia, resulting in reduced asymmetry of feedback and feedforward connections in the frontoparietal network. Dominant feedback connectivity returned when patients recovered from anesthesia. Both analytic techniques and both classes of anesthetics demonstrated similar results in this heterogeneous population of surgical patients. CONCLUSIONS: The disruption of dominant feedback connectivity in the frontoparietal network is a common neurophysiologic correlate of general anesthesia across two anesthetic classes and two analytic measures. This study represents a key translational step from the underlying cognitive neuroscience of consciousness to more sophisticated monitoring of anesthetic effects in human surgical patients.

The effects of sevoflurane with propofol and remifentanil on tracheal intubation conditions without neuromuscular blocking agents.

BACKGROUND: Propofol and remifentanil are used for tracheal intubation in the absence of neuromuscular blocking agents. We hypothesized that the addition of sevoflurane to propofol and remifentanil would improve intubation conditions and provide hemodynamic stability. METHODS: Seventy-six patients scheduled for elective surgery were randomly allocated to be ventilated with either 4% (group I) or 7% sevoflurane (group II) after propofol injection (2 mg/kg). All patients received remifentanil (1 microg/kg) 30 seconds after administration of propofol. Ninety seconds after remifentanil was given, laryngoscopy and tracheal intubation were performed. Intubation conditions and hemodynamic changes were evaluated. RESULTS: The overall incidence of clinically acceptable intubation conditions was significantly higher in group II (92%) than group I (58%) (P = 0.001). Scores for vocal cord position, coughing, and limb movement were significantly better in group II (P < 0.05). Mean blood pressure remained significantly lower than the pre-induction level throughout the investigation in both groups (P < 0.001), but there was no incidence of bradycardia or hypotension requiring treatment. CONCLUSIONS: Tracheal intubation without neuromuscular blocking agents can be achieved safely and reliably by adding 7% sevoflurane to propofol (2 mg/kg) and remifentanil (1 microg/kg).

Comparison of the effects of propofol and pentobarbital on hydrogen peroxide-stimulated hepatic SNU761 cells.

BACKGROUND: Propofol and barbiturates are both known to protect cells of several organs against ischemia/reperfusion injury, but there are few reports on any possible protective effects on human hepatocytes. We investigated the activities of both agents on human hepatic SNU761 cells under hydrogen peroxide (H(2)O(2))-induced oxidative stress. METHODS: To determine whether propofol and pentobarbital protect hepatocytes from H(2)O(2)-induced toxicity, we used SNU761 cells, a human hepatocellular carcinoma (HCC) cell line. Cells were pretreated with different dosages (1, 10, 50 microM) of propofol or pentobarbital (1, 10, 50, 100, 400 microM) 30 min before H(2)O(2) application. Lactate dehydrogenase (LDH) was measured to assess and quantify cell death. To determine the nature of cell death, treated hepatocytes were doubly stained with fluorescein isothiocyanate (FITC)-labeled Annexin V and propidium iodide (PI), and analyzed by flow cytometry. RESULTS: Pretreatment with propofol, but not pentobarbital, suppressed H(2)O(2)-induced LDH release. In Annexin V-FITC/PI binding analysis, propofol decreased the number of necrotic and late apoptotic cells, but no significant decreases in such cell numbers were seen when pentobarbital was used. CONCLUSIONS: Unlike pentobarbital, propofol, at clinical concentrations, protected SNU-761 HCC cells against oxidative stress.

Effects of propofol and etomidate on hydrogen peroxide-induced oxidative damage in hepatocyte.

BACKGROUND: The present investigation was undertaken to evaluate the protective effect of propofol and etomidate against hydrogen peroxide (H2O2) induced oxidative damage in human hepatic SNU761 cells by measuring lactate dehydrogenase (LDH). METHODS: The cell line of human hepatocellular carcinoma was grown for 24 hours in dissociated cell culture. They were divided into eight groups: negative control (NC) group with no drug administration, positive control (PC) group with H2O2 250 micrometer and other groups pretreated with propofol (P; 1, 10, 50 micrometer) or etomidate (ET; 1, 10, 50 micrometer) followed H2O2 administration. After 7 hours, cell death was assessed by morphology under the light microscope and quantified by measuring the LDH in the culture media. RESULTS: In the light microscopic findings, the intact cells were increased in all three propofol groups compared to group PC. H2O2-induced LDH production was also significantly suppressed in all three propofol groups compared to group PC (P < 0.001). There were no significant differences in the microscopic findings and LDH production between the etomidate groups and group PC. CONCLUSIONS: These results suggest that the propofol has protective effect on the hepatocyte against H2O2-induced oxidative stress.

Protective effect of isoflurane anesthesia on noise-induced hearing loss in mice.

HYPOTHESIS/OBJECTIVES: To examine the protective effect of general anesthesia with isoflurane against noise-induced hearing loss in mice. STUDY DESIGN: Animal study using noise stimulation and measurement of hearing in BALB/c mice. METHODS: Mice were exposed to 122 dB peak equivalent sound pressure level click noise for 3 hours per day for 3 consecutive days with or without anesthesia using isoflurane. Hearing levels were measured and hair cell survival ratio was observed. RESULTS: In mice without anesthesia, hearing threshold increased after noise stimulation (73.7 dB hearing level [HL]) and persisted for at least 1 month. However, in mice exposed to noise under anesthesia, hearing loss was less severe (44.1 dB HL) and had recovered more (26.5 dB HL) by one month. Histological examination showed hair cell survival was higher in anesthetized compared to non-anesthetized mice. CONCLUSION: These data indicate isoflurane general anesthesia protects against noise-induced hearing loss and tissue damage in mice.