Development and Application of a New Type of Medical Protective Sputum Suction Respiratory Circuit

Background: At present, there are few breathing circuits that can protect health care workers. Here, we have developed a new disposable medical protective sputum suction breathing circuit.Methods：The main components of the structure of the novel medical protective breathing circuit are adapter, isolation sleeve, stop sleeve, sealing cover and sealing ring. An isolation sleeve is inserted into the conversion joint. The isolation sleeve inner sleeve has a stop sleeve with an inverted round table structure. The upper nozzle of the adapter is provided with a sealing ring tightly combined with the lower outer edge of the isolation sleeve, and a sealing cover is provided on the sealing ring.Results: The device is easy to operate and can prevent the pollution caused by sputum splashing when sucking sputum.Conclusion: The medical protective sputum suction and breathing circuit is simple in structure, easy to use, and can effectively protect medical staff.

Waste Anesthetic Gase: A Forgotten Problems

Waste anesthetic gas (WAG) is a small amount of inhaled anesthetic gas that comes out of the patient’s anesthesia breathing circuit into the envorinment air while the patient is under anesthesia. According to American Occupation Safety and HealthAdministration (OSHA) more than 200.000 healthcare workers especially aneaesthesiologist, surgery nurse, obstetrician and surgeons are at risk of developing work-related disease due to chronic exposure to WAG. Exposure to WAG in short time associated with multiple problems such as headaches, irritability, fatigue, nausea, drowsiness, decrease work efficiency and difficulty with judgment and coordination. While chronic exposure of WAG is associated with genotoxicity, mutagenicity, oxidative stress, fatigue, headache, irritability, nausea, nephrotoxic, neurotoxic, hepatotoxic, immunosuppressive and reproductive toxicological effect. Waste anesthetic gases are known as environmental pollutants and will be released from the OR to the outside environment then the substance will reach the atmosphere damaging ozone layer. Exposure to trace WAG in the perioperative environment cannot be eliminated completely,but it can be controlled. Controlling WAG can be achieve by using scavenging system, proper ventilation, airway management, ideal anesthetic choice, maintaining anesthesia machine and equipment, hospital regulation and routine healthcare workers health status examination.

Incidental operating room fire from a breathing circuit warmer system: a case report

Background An airway-associated fire in an operating room can have devastating consequences for patients. Breathing circuit warmers (BCWs) are widely used to provide heated and humidified anesthetic gases and eventually prevent hypothermia during general anesthesia. Herein, we describe a case of a BCW-related airway fire. Case presentation In this case, an electrical short within a BCW wire caused a fire inside the circuit. Simultaneously, the fire was extinguished, ventilation was stopped, and the endotracheal tube was disconnected from the BCW. The patient was exposed to the fire for less than 10 s, resulting in burns to the trachea and bronchi. Immediately after airway burn, bronchoscopy showed no edema or narrowing except for soot in the trachea and both main bronchus. After the inhalation burn event, prophylactic antibiotics, bronchodilator, mucolytics nebulizer, and corticosteroid nebulizer were started. On bronchoscopy 3 days after the inhalation burn, mucosal erythematous edema was observed and the inflammatory reaction worsened. The inflammatory reaction showed aggravation for up to 2 weeks, and then gradually recovered, and the epithelium and mucous membrane of the upper respiratory tract returned to normal after 4 weeks. Eventually, the patient recovered without long-term complications and was successfully discharged. Conclusions This is the first report of a fire caused by BCW. We wanted to share our experience of how we responded to an airway-related fire in an OR and treated the patient. It cannot be overemphasized that the electrical medical appliance associated with the airways are fatal to the patient in the event of a fire, so caution should always be exercised.

Quality Fade in Medical Device Manufacturing: Thinness of Airway Breathing Circuit Plastic

Mechanical respirators typically use a plastic circuit apparatus to pass gases from the ventilator to the patient. Structural integrity of these circuits is crucial for maintaining oxygenation. Anesthesiologists, respiratory therapists, and other critical care professionals rely on the circuit to be free of defects. The American Society for Testing and Materials maintains standards of medical devices and had a standard (titled Standard Specification for Anesthesia Breathing Tubes) that included circuits. This standard, which was last updated in 2008, has since been withdrawn. Lack of a defined standard can invite quality fade—the phenomenon whereby manufacturers deliberately but surreptitiously reduce material quality to widen profit margins. With plastics, this is often in the form of thinner material. A minimum thickness delineated in the breathing circuit standard would help ensure product quality, maintain tolerance to mechanical insults, and avert leaks. Our impression is that over the recent years, the plastic in many of the commercially available breathing circuits has gotten thinner. We experienced a circuit leak in the middle of a laminectomy due to compromised plastic tubing in a location that evaded the safety circuit leak check that is performed prior to surgery. This compromised ventilation and oxygenation in the middle of a surgery in which the patient is positioned prone and hence with a minimally accessible airway; it could have resulted in anoxic brain injury or death. The incident led us to reflect on the degree of thinness of the circuit's plastic.

Experimental Investigation on Water Adsorption Using Laser Photoacoustic Spectroscopy and Numerical Simulations

In the present research we propose a model to assess the water vapors adsorption capacity of a SiO2 trap in the breathing circuit, aiming to reduce the loading of interfering compounds in human breath samples. In this study we used photoacoustic spectroscopy to analyze the SiO2 adsorption of interfering compounds from human breath and numerical simulations to study the flow of expired breath gas through porous media. As a result, the highest adsorption rate was achieved with a flow rate of 300 sccm, while the lowest rate was achieved with a flow rate of 600 sccm. In the procedure of H2O removal from the human breath air samples, we determined a quantity of 213 cm3 SiO2 pearls to be used for a 750 mL sampling bag, in order to keep the detection of ethylene free of H2O interference. The data from this study encourages the premise that the SiO2 trap is efficient in the reduction of interfering compounds (like water vapors) from the human breath.

Deviation from Clinical Routines Can Reveal Sources of Device Design Vulnerability

The ability to adequately ventilate a patient is critical and sometimes a challenge in the emergency, intensive care, and anesthesiology settings. Commonly, initial ventilation is achieved through the use of a face mask in conjunction with a bag that is manually squeezed by the clinician to generate positive pressure and flow of air or oxygen through the patient's airway. Large or small erroneous openings in the breathing circuit can lead to leaks that compromise ventilation ability. Standard procedure in anesthesiology is to check the circuit apparatus and oxygen delivery system prior to every case. Because the face mask itself is not a piece of equipment that is associated with a source of leak, some common anesthesia machine designs are constructed such that the circuit is tested without the mask component. We present an example of a leak that resulted from complete failure of the face mask due to a tiny tear in its cuff by the patient's sharp teeth edges. This subsequently prevented formation of a seal between the face mask and the patient's face and rendered the device incapable of generating the positive pressure it is designed to deliver. This instance depicts the broader lesson that deviation from clinical routines can reveal unappreciated sources of vulnerability in device design.

Environmental And Economic Impact of Using A Higher Efficiency Ventilator And Vaporizer During Surgery Under General Anesthesia: A Randomized Controlled Prospective Cohort

Background: Compared to traditional breathing circuits, low-flow anesthesia machines utilize a low-volume breathing circuit system by injecting volatile agent into the circuit mainly during inspiration. We aimed to assess whether Maquet Flow-i C20 anesthesia workstation delivers volatile anesthetic more efficiently than a GE Aisys CS2 during elective general surgery. Methods: Eligible candidates enrolled in the study (2014-1248) met the following inclusion criteria: 18 – 65 years old, scheduled for surgery requiring general anesthesia at UC Irvine Health, and expected to receive sevoflurane for the duration of the procedure. Exclusion criteria: < 18 years old, history of COPD, cardiovascular disease, sevoflurane sensitivity, BMI > 30 kg/m2, ASA > 2, pregnant, or surgery scheduled < 120 minutes. We calculated the total amount of sevoflurane delivered and consumption rates during induction/maintenance periods and compared the groups using parametric testing (Student’s t-Test). Results: In total, 103 subjects (Maquet: n=52, GE: n=51) were analyzed. Overall, the Flow-i C-20 group consumed significantly less sevoflurane (95.5 ± 49.3 g) compared to the Aisys2 (118.2 ± 62.4 g) (p = 0.043 for group difference) corresponding to an approximately 20% efficiency improvement in overall agent delivery. When accounting for the fresh gas flow setting, agent concentration and length of induction, the Maquet machines delivered volatile agent at a significantly lower rate compared to the GE devices (7.4 ± 3.2 L/min vs. 9.2 ± 4.1 L/min; p = 0.017). Based on these results, we estimate that the Maquet Flow-i workstations can save an estimated average of $239,440 over the expected 10-year machine lifespan. This 20% decrease in CO2 equivalent emissions corresponds to 201 metric tons less greenhouse gas emissions over a decade compared to the GE Aisys; equivalent to 491,760 miles driven by an average passenger vehicle or 219,881 pounds of coal burned.Conclusions: Overall, our results from this pilot study suggest that the Maquet Flow-i delivers significantly less (~20%) volatile agent during routine elective surgery using a standardized anesthetic protocol compared to a traditional anesthesia system. The results demonstrate a strong opportunity for economic and environmental benefits if implemented across other medical institutions.

Choosing optimal anesthetic and method of general anesthesia for laser surgery retinopathy of prematurity

Purpose. Comparative analysis of clinical efficacy and safety of inhalational general anesthesia (GA) with halothane and sevoflurane in premature infants with retinopathy of prematurity (ROP) during laser coagulation (LC) of the avascular retina. Material and methods. The clinical material included 284 children who underwent laser surgery of ROP in the period from 2008 to 2017 (method of continuous sampling). Introduction to anesthesia and maintenance of anesthesia was performed by inhalation of anesthetic (halothane or sevoflurane) with O2 using face mask and Mapleson breathing circuit. Two groups were formed: in the 1st group (167 people) halothane was used at anesthetic at oxygen concentration of 0.3 vol%, in the 2nd group (117 people) – sevoflurane at concentration of 1–1.5 vol%. Results. In case of GA with halothane in children of the 1st group, in 68 children (40.7%) developed negative reactions during anesthesia in the form of of respiratory depression, in several cases – up to pronounced bradypnea, bradycardia, prolonged awakening after surgery. In the 2nd group with GA with sevoflurane, negative reactions in the form of moderate bradycardia and bradypnea were observed only in 14 children (11.9%). All complications and reactions were promptly eliminated in all cases. Conclusion. Based on the obtained results, the optimal inhalation anesthetic for LC of retina in premature infants is sevoflurane in low concentrations (at the sedation level) using the Mapleson breathing circuit and face mask. With this method of anesthesia, the frequency of side effects of sevoflurane, negative reactions during anesthesia and the degree of their severity are extremely low. Key words: premature infants, retinopathy of premature, sevoflurane, general anesthesia, laser coagulation of the retina.

Correlation of exhaled propofol with Narcotrend index and calculated propofol plasma levels in children undergoing surgery under total intravenous anesthesia - an observational study

Background Exhaled propofol concentrations correlate with propofol concentrations in adult human blood and the brain tissue of rats, as well as with electroencephalography (EEG) based indices of anesthetic depth. The pharmacokinetics of propofol are however different in children compared to adults. The value of exhaled propofol measurements in pediatric anesthesia has not yet been investigated. Breathing system filters and breathing circuits can also interfere with the measurements. In this study, we investigated correlations between exhaled propofol (exP) concentrations and the Narkotrend Index (NI) as well as calculated propofol plasma concentrations. Methods A multi-capillary-column (MCC) combined with ion mobility spectrometry (IMS) was used to determine exP. Optimal positioning of breathing system filters (near-patient or patient-distant) and sample line (proximal or distal to filter) were investigated. Measurements were taken during induction (I), maintenance (M) and emergence (E) of children under total intravenous anesthesia (TIVA). Correlations between ExP concentrations and NI and predicted plasma propofol concentrations (using pediatric pharmacokinetic models Kataria and Paedfusor) were assessed using Pearson correlation and regression analysis. Results Near-patient positioning of breathing system filters led to continuously rising exP values when exP was measured proximal to the filters, and lower concentrations when exP was measured distal to the filters. The breathing system filters were therefore subsequently attached between the breathing system tubes and the inspiratory and expiratory limbs of the anesthetic machine. ExP concentrations significantly correlated with NI and propofol concentrations predicted by pharmacokinetic models during induction and maintenance of anesthesia. During emergence, exP significantly correlated with predicted propofol concentrations, but not with NI. Conclusion In this study, we demonstrated that exP correlates with calculated propofol concentrations and NI during induction and maintenance in pediatric patients. However, the correlations are highly variable and there are substantial obstacles: Without patient proximal placement of filters, the breathing circuit tubing must be changed after each patient, and furthermore, during ventilation, a considerable additional loss of heat and moisture can occur. Adhesion of propofol to plastic parts (endotracheal tube, breathing circle) may especially be problematic during emergence. Trial Registration The study was registered in the German registry of clinical studies (DRKS-ID: DRKS00015795).