CASE REPORT


https://doi.org/10.5005/jp-journals-11010-1073
Indian Journal of Respiratory Care
Volume 12 | Issue 4 | Year 2023

A Case Report on Use of Anesthetic Conserving Device in a Patient with Bullous Cystic Lung Disease


Kankana D Samanta1, Arindam Kar2

1,2Critical Care Unit, Sir HN Reliance Foundation Hospital and Research Centre, Mumbai, Maharashtra, India

Corresponding Author: Kankana D Samanta, Critical Care Unit, Sir HN Reliance Foundation Hospital and Research Centre, Mumbai, Maharashtra, India, Phone: +91 7769953049, e-mail: kd.samanta@rediffmail.com

Received: 06 June 2023; Accepted: 10 November 2023; Published on: 18 January 2024

ABSTRACT

Aim and background: Mechanical ventilation is a lifesaving intervention used in critically ill patients with respiratory failure. However, it is not without risks, as it can cause harm to the lungs, increase the need for sedatives and analgesics, and prolong the time patients spend on mechanical ventilation. One way to mitigate these risks is by using an anesthetic conserving device (ACD).

With the use of ACD, the use of volatile anesthetics like sevoflurane has been available for intensive care unit (ICU) critically ill patients having chronic pulmonary diseases for faster awakening, preventing critical myopathy and quicker weaning from the ventilator.

Case description: In this case study, a 42-year-old female patient presented to the emergency room (ER) with a complaint of breathlessness persisting for 2 days. The patient had a medical history of left recurrent pneumothorax and bullous cystic lung disease. Upon admission to the ER, the patient exhibited drowsiness and hypotension, and arterial blood gas (ABG) analysis revealed severe respiratory acidosis. Consequently, the medical team decided to intubate the patient using pressure-regulated volume control (PRVC) ventilation while administering sedation and paralysis with atracurium, fentanyl, and a ketamine infusion.

The use of ketamine infusion was initiated due to the acute exacerbation of chronic obstructive pulmonary disease (COPD), specifically type II respiratory failure. Employing an ACD proved to be highly beneficial in enhancing gas exchange and achieving more effective sedation. This approach facilitated quicker awakening and smoother weaning trials, a significant advantage when dealing with chronic pulmonary patients on mechanical ventilation. Remarkably, the patient was successfully transitioned to pressure support ventilation mode within just 4 days of implementing the ACD. Subsequently, the patient was extubated and placed on noninvasive ventilation, marking a successful outcome.

Conclusion: This is a case study on the use of an ACD that facilitated quicker awakening and improved gas exchange, thereby reducing hypercarbia and peak airway pressures. Ultimately, this led to quicker weaning from the ventilator.

Clinical significance: By utilizing an ACD, it has become possible to administer volatile anesthetics such as sevoflurane to critically ill patients in the ICU who suffer from chronic pulmonary diseases. This approach facilitates quicker awakening, helps prevent critical myopathy, and expedites the process of weaning patients from ventilatory support.

How to cite this article: Samanta KD, Kar A. A Case Report on Use of Anesthetic Conserving Device in a Patient with Bullous Cystic Lung Disease. Indian J Respir Care 2023;12(4):355–357.

Source of support: Nil

Conflict of interest: None

Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.

Keywords: Anesthetic conserving device, Case report, Chronic obstructive pulmonary disease, Hypercarbia, Mechanical ventilator, Weaning

INTRODUCTION

Mechanical ventilation is a lifesaving intervention used in critically ill patients with respiratory failure. However, it is not without risks, as it can cause harm to the lungs, increase the need for sedatives and analgesics, and prolong the time patients spend on mechanical ventilation. One way to mitigate these risks is by using an anesthetic conserving device (ACD).

Effective sedation and analgesia are of utmost importance in intensive care unit (ICU) to reduce pain, anxiety, and delirium during mechanical ventilation.1,2An ACD is a device that is placed between the patient and the ventilator circuit, which captures exhaled anesthetic gases and recycles them back to the patient during the next inhalation. This allows for a reduction in the number of anesthetic agents required, thereby reducing the risk of adverse effects associated with their use. In addition to reducing the number of anesthetic agents needed, ACDs have also been shown to benefit patients with bronchospasm. Bronchospasm is a condition characterized by constriction of the airways, which can lead to difficulty in breathing. ACDs have been found to reduce the incidence and severity of bronchospasm in mechanically ventilated patients, likely due to the decreased need for anesthetic agents, which can irritate the airways. Overall, the use of ACDs can lead to improved outcomes in mechanically ventilated patients, including reduced risk of lung injury, decreased need for sedation and analgesia, and improved management of bronchospasm.AnaConDa (Anesthetic Conserving Device), manufactured by Sedana Medical, is a medical device designed to reduce the amount of anesthetic gases that are released into the environment during mechanical ventilation of patients. It is an innovative device that helps to minimize the use of anesthetic agents, thereby reducing the cost of healthcare and environmental pollution. The AnaConDa device is equipped with a sidestream monitoring system that can measure the minimum alveolar concentration (MAC) and fraction of expired inspired nitrous oxide (Fet%) values in mechanically ventilated patients. This monitoring system allows for accurate and continuous measurement of the patient’s level of anesthesia, which can help clinicians adjust the anesthetic dosage and minimize the risk of over-sedation.3

Set-up of the AnaConDa device on mechanically ventilated patient—the device was connected between the Y-piece and catheter mount. There was no heat and moisture exchanger (HME) filter to be connected as the device itself works like an HME. There are two connection lines—one is the pressure monitoring line which needs to be connected on the side stream capnography and the other one into the syringe adapter where the anesthetic agent is filled up (Fig. 1).3

Fig. 1: Connection of the AnaConDa device to the patient

CASE DESCRIPTION

A 42-year-old female patient presented to the emergency room (ER) with a chief complaint of breathlessness lasting for 2 days. Her past medical history included a left recurrent pneumothorax and bullous cystic lung disease. She had previously undergone pleurodesis surgery. Upon admission to the ER, the patient exhibited drowsiness, hypotension, and severe respiratory acidosis, as evidenced by arterial blood gas (ABG) results. Consequently, she was intubated using pressure-regulated volume control (PRVC) ventilation, and she was sedated and paralyzed using atracurium in combination with fentanyl and ketamine infusions. The decision to initiate a ketamine infusion was made due to the acute exacerbation of chronic obstructive pulmonary disease (COPD), classified as type II respiratory failure. The patient was ventilated on PRVC mode with the following settings—FiO2 at 45%, PEEP at 5 cms of H2O, respirate rate at 28 breath per minute, tidal volume at 320 mL where observed peak inspiratory pressures (PIP) was 44 cm H2O. Given her hemodynamic instability, she was also placed on noradrenaline and vasopressin infusions. Nebulizations were started and administered through an in-line nebulizer. Initially, end-tidal carbon dioxide (EtCO2) levels were shooting up around 80; we thereby thought of reduction in dead space by removing the filter and utilizing a collapsible catheter mount. Upon chest auscultation, spasm and severe wheezing were detected. As a therapeutic measure, the patient was started on an aminophylline drip administered at a rate of 20 mL/hour for 20 hours.

Despite 2 days of ventilation, the patient continued to experience severe wheezing and hypercarbia. Consequently, the medical team considered implementing the use of the AnaConDa (Anesthetic Conserving Device). A sevoflurane infusion was initiated at a rate of 5 mL/hour, while the ketamine infusion rate was reduced from 5 mL/hour to 1 mL/hour.

Initially, we were accepting a MAC value of 0.5–1, as mentioned in Table 1. The patient’s pulse rate was initially on the higher side upon the initiation of sevoflurane, but it subsequently stabilized over the following days. This improvement in lung compliance and better gas exchange occurred as the patient awakened and experienced reduced bronchospasm. We were able to transition the patient to pressure support ventilation mode by comparing the first day of initiation to the last day, which resulted in a significant reduction in EtCO2 levels and improved lung compliance, consequently reducing PIPs.

Table 1: Monitoring parameters during use of ACD
Ventilator Ventilator Ventilator Ventilator
FiO2 45 FiO2 45 FiO2 35 FiO2 35
PEEP 4 PEEP 4 PEEP 4 PEEP 4
RR 22 RR 26 RR 20 RR 20
TV 380 TV 360 TV 400 TV 400
Monitoring Monitoring Monitoring Monitoring
MAC 0.8 MAC 0.5 MAC 0.4 MAC 0.5
inSev 1.1 inSev 0.6 inSev 0.5 inSev 0.5
etSev 1.6 etSev 1.3 etSev 0.5 etSev 0.95
EtCO2 88 EtCO2 75 EtCO2 60 EtCO2 56
PIP 48 PIP 46 PIP 44 PIP 38
Sedation Sedation Sedation Sedation
Ketamine 10 mg Ketamine 10 mg Ketamine 20 mg Ketamine 20 mg
Atracurium 20 mg Sevoflurane 6 mL Sevoflurane 6 mL Sevoflurane 6 mL
Aminophylline 20 mL Aminophylline 20 mL

*etSev, end-tidal concentrations of sevoflurane; *inSev, inspiratory sevoflurane; MAC, minimum alveolar concentration; PIP, peak inspiratory pressures on ventilator

In previous studies, CO2 rebreathing was identified as a limiting factor for the use of an ACD.4 However, in this case, the device actually enhanced gas exchange, leading to a reduction in hypercarbia. The utilization of the ACD contributed to improved gas exchange and a more efficient sedation effect, facilitating quicker awakening and weaning trials for this type of chronic pulmonary patient from mechanical ventilation. Remarkably, we were able to wean the patient to pressure support ventilation mode within just 4 days of implementing the ACD. Subsequently, the patient was successfully extubated and transitioned to noninvasive ventilation.

Working of the AnaConDa device—we connected the 50 mL AnaConDa device attached between the Y connector and catheter mount. Do not attach any extra HME filter as it can absorb the inhalational agent and will hamper the proper functioning of the AnaConDa. It is a single-used device and should be replaced every 48 hours or as needed. Liquid anesthetic agent is delivered through the anesthetic agent line, as shown in the below diagram. The anesthetic agent is vaporized with help of the evaporator rod and is then inhaled by the patient with ventilator inspiratory flow. With continuous breathing, majority of anesthetic agent not absorbed by the lungs is then absorbed by the activated carbon filter during exhalation, which on further inhalation, is transported back to the lungs, reducing the amount of anesthetic agent wasted. There is a gas analyzer port that is used to measure the exhaled anesthetic concentration in MAC value or end tidal concentration (Fet%). We arranged a special monitor having side stream gas monitoring, measuring continuously the concentrations of CO2 and the anesthetic gas used (sevoflurane).

The utilization of an ACD on mechanically ventilated patients offers several advantages, including shorter awakening times, the ability for patients to breathe spontaneously, reduced anesthetic accumulation, enhanced gas exchange, improved lung compliance, and facilitation of the weaning process.

DISCUSSION

With the arrival of ACDs, the use of these volatile anesthetics in ICU can finally be available and benefit some groups of critically ill patients like interstitial lung disease (ILD) and COPD with severe spasm and thereby difficult to wean. It is also recommended and studied for recovery from its sedation effect faster than using propofol or other sedatives and thus resulted in shorter duration on ventilator.5

The chart above (Fig. 2) illustrates a substantial decrease in EtCO2 values and a reduction in peak inspiratory airway pressures (PIP). This data supports the conclusion that the use of an ACD improves gas exchange while maintaining sedation and its associated effects. However, it is important to note that there have been limited studies conducted in this regard. Further research and additional cases are needed to thoroughly investigate and observe the potential for CO2 retention when using the ACD.

Fig. 2: Improved gas exchange showing reduced EtCO2 and PIP

CONCLUSION

This case report introduces a novel approach by implementing an ACD that focuses on treating critically ill patients with such chronic pulmonary diseases. Set this case report apart, as to treat these patients, we often face challenges in sedation management due to their compromised respiratory function. So, the use of volatile anesthetic agents might present a new approach of minimizing the respiratory complications by maintaining sedation and faster awakening. The focus on faster awakening, prevention of critical myopathy, and potential for quicker ventilator weaning establishes this report as a significant contribution to ICU sedation strategies. Further studies need to be done to identify other potential benefits that could be used significantly in patients.

Clinical Significance

With the use of an ACD, the use of volatile anesthetics like sevoflurane has been available for ICU critically ill patients having chronic pulmonary diseases for faster awakening, preventing critical myopathy and quicker weaning from the ventilator.

REFERENCES

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2. Sessler CN, Varney K. Patient-focused sedation and analgesia in the ICU. Chest 2008;133(2):552–565. DOI: 10.1378/chest.07-2026

3. Farrell R, Oomen G, Carey P. A technical review of the history, development and performance of the anesthetic conserving device “AnaConDa” for delivering volatile anesthetic in intensive and post-operative critical care. J Clin Monit Comput 2018;32(4):595–604. DOI: 10.1007/s10877-017-0097-9

4. Sturesson LW, Bodelsson M, Jonson B, et al. Anesthetic conserving device AnaConDa: dead space effect and signiႡcance for lung protective ventilation. Br J Anaesth 2014;113(3):508–514. DOI: 10.1093/bja/aeu102

5. Röhm KD, Wolf MW, Schöllhorn T, et al. Short-term sevoflurane sedation using the Anesthetic Conserving Device after cardiothoracic surgery. Intensive Care Med 2008;34(9):1683–1689. DOI: 10.1007/s00134-008-1157-x

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