A Case of Brainstem Anesthesia after Retrobulbar Block for Globe Rupture Repair

Purpose. To present a rare case of brainstem anesthesia from retrobulbar block and discuss evidence-based methods for reducing the incidence of this complication. Case. A 72-year-old female, was given a retrobulbar block of 5 mL of bupivacaine 0.5% for postoperative pain management, after a globe rupture repair under general anesthesia. Prior to injection, the patient was breathing spontaneously via the anesthesia machine circuit and had not received any additional narcotics/muscle relaxants for 2.5 hr (with full recovery of neuromuscular blocking agent after anesthetic reversal). Over 7 min, however, there was a steady increase in ETCO2 and the patient became apneic, consistent with brainstem anesthesia. She remained intubated and was transported to the postanesthesia care unit for prolonged monitoring, with eventual extubation. Discussion. Brainstem anesthesia is an important complication to recognize as it can lead to apnea and death. The judicious use of anesthetic volume, shorter needle tips, and mixed formulations can help reduce the chance of brainstem anesthesia. Observation of the contralateral eye 5–10 minutes after injection for pupillary dilation, and prior to surgical draping, can help identify early CNS involvement.

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.

Preparation of Dräger Atlan A350 and General Electric Healthcare Carestation 650 anesthesia workstations for malignant hyperthermia susceptible patients

Background Patients at risk of malignant hyperthermia need trigger-free anesthesia. Therefore, anesthesia machines prepared for safe use in predisposed patients should be free of volatile anesthetics. The washout time depends on the composition of rubber and plastic in the anesthesia machine. Therefore, new anesthesia machines should be evaluated regarding the safe preparation for trigger-free anesthesia. This study investigates wash out procedures of volatile anesthetics for two new anesthetic workstations: Dräger Atlan A350 and General Electric Healthcare (GE) Carestation 650 and compare it with preparation using activated charcoal filters (ACF). Methods A Dräger Atlan and a Carestation 650 were contaminated with 4% sevoflurane for 90 min. The machines were decontaminated with method (M1): using ACF, method 2 (M2): a wash out method that included exchange of internal parts, breathing circuits and soda lime canister followed by ventilating a test lung using a preliminary protocol provided by Dräger or method 3 (M3): a universal wash out instruction of GE, method 4 (M4): M3 plus exchange of breathing system and bellows. Decontamination was followed by a simulated trigger-free ventilation. All experiments were repeated with 8% desflurane contaminated machines. Volatile anesthetics were detected with a closed gas loop high-resolution ion mobility spectrometer with gas chromatographic pre-separation attached to the bacterial filter of the breathing circuits. Primary outcome was time until < 5 ppm of volatile anesthetics and total preparation time. Results Time to < 5 ppm for the Atlan was 17 min (desflurane) and 50 min (sevoflurane), wash out continued for a total of 60 min according to protocol resulting in a total preparation time of 96-122 min. The Carestation needed 66 min (desflurane) and 24 min (sevoflurane) which could be abbreviated to 24 min (desflurane) if breathing system and bellows were changed. Total preparation time was 30-73 min. When using active charcoal filters time to < 5 ppm was 0 min for both machines, and total preparation time < 5 min. Conclusion Both wash out protocols resulted in a significant reduction of trace gas concentrations. However, due to the complexity of the protocols and prolonged total preparation time, feasibility in clinical practice remains questionable. Especially when time is limited preparation of the anesthetic machines using ACF remain superior.

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.

Comparing Ventilation Parameters for COVID-19 Patients Using Both Long-Term ICU and Anesthetic Ventilators in Times of Shortage

In the first months of the COVID-19 pandemic in Europe, many patients were treated in hospitals using mechanical ventilation. However, due to a shortage of ICU ventilators, hospitals worldwide needed to deploy anesthesia machines for ICU ventilation (which is off-label use). A joint guidance was written to apply anesthesia machines for long-term ventilation. The goal of this research is to retrospectively evaluate the differences in measurable ventilation parameters between the ICU ventilator and the anesthesia machine as used for COVID-19 patients. In this study, we included 32 patients treated in March and April 2020, who had more than 3 days of mechanical ventilation, either in the regular ICU with ICU ventilators (Hamilton S1), or in the temporary emergency ICU with anesthetic ventilators (Aisys, GE). The data acquired during regular clinical treatment was collected from the Patient Data Management Systems. Available ventilation parameters (pressures and volumes: PEEP, Ppeak, Pinsp, Vtidal), monitored parameters EtCO2, SpO2, derived compliance C, and resistance R were processed and analyzed. A sub-analysis was performed to compare closed-loop ventilation (INTELLiVENT-ASV) to other ventilation modes. The results showed no major differences in the compared parameters, except for Pinsp. PEEP was reduced over time in the with Hamilton treated patients. This is most likely attributed to changing clinical protocol as more clinical experience and literature became available. A comparison of compliance between the 2 ventilators could not be made due to variances in the measurement of compliance. Closed loop ventilation could be used in 79% of the time, resulting in more stable EtCO2. From the analysis it can be concluded that the off-label usage of the anesthetic ventilator in our hospital did not result in differences in ventilation parameters compared to the ICU treatment in the first 4 days of ventilation.