Usefulness of Inhaled Sedation in Patients With Severe ARDS Due to COVID-19

BACKGROUND

Sedation in intensive care is fundamental for optimizing clinical outcomes. For many years the world has been facing high rates of opioid use, and to combat the increasing opioid addiction plans at both national and international level have been implemented.1 The COVID-19 pandemic posed a major challenge for health systems and also increased the use of sedatives and opioid analgesia for prolonged periods of time, and at high doses, in a significant proportion of patients. In our institutions, the shortage of many drugs for intravenous (IV) analgosedation forces us to alternatives to replace out-of-stock drugs or to seek sedation goals, which are difficult to obtain with traditional drugs at high doses.2 METHODS: This was an analytical retrospective cohort study evaluating the follow-up of subjects with inclusion criteria from ICU admission to discharge (alive or dead). Five end points were measured: need for high-dose opioids (≥ 200 µg/h), comparison of inhaled versus IV sedation of opioid analgesic doses, midazolam dose, need for muscle relaxant, and risk of delirium.

RESULTS

A total of 283 subjects were included in the study, of whom 230 were administered IV sedation and 53 inhaled sedation. In the inhaled sedation group, the relative risks (RRs) were 0.5 (95% CI 0.4-0.8, P = .045) for need of high-dose fentanyl, 0.3 (95% CI 0.20-0.45, P < .001) for need of muscle relaxant, and 0.8 (95% CI 0.61-1.15, P = .25) for risk of delirium. The median difference of fentanyl dose between the inhaled sedation and IV sedation groups was 61 µg/h or 1,200 µg/d (2.2 ampules/d, P < .001), and that of midazolam dose was 5.7 mg/h.

CONCLUSIONS

Inhaled sedation was associated with lower doses of opioids, benzodiazepines, and muscle relaxants compared to IV sedation. This therapy should be considered as an alternative in critically ill patients requiring prolonged ventilatory support and where IV sedation is not possible, always under adequate supervision of ICU staff.

General anesthetic techniques for enhanced recovery after surgery: Current controversies

General anesthesia technique can influence not only immediate postoperative outcomes, but also long-term outcomes beyond hospital stay (e.g., readmission after discharge from hospital). There is lack of evidence regarding superiority of total intravenous anesthesia over inhalation anesthesia with regards to postoperative outcomes even in high-risk population including cancer patients. Optimal balanced general anesthetic technique for enhance recovery after elective surgery in adults includes avoidance of routine use preoperative midazolam, avoidance of deep anesthesia, use of opioid-sparing approach, and minimization of neuromuscular blocking agents and appropriate reversal of residual paralysis. Given that the residual effects of drugs used during anesthesia can increase postoperative morbidity and delay recovery, it is prudent to use a minimal number of drug combinations, and the drugs used are shorter-acting and administered at the lowest possible dose. It is imperative that the discerning anesthesiologist consider whether each drug used is really necessary for accomplishing perioperative goals.

Malignant Hyperthermia Syndrome: A Clinical Case Report

Malignant hyperthermia is a pharmacogenetic disorder. It manifests as a hypercatabolic skeletal muscle syndrome linked to inhaled volatile anesthetics or depolarizing muscle relaxants. Its clinical signs and symptoms are tachycardia, hyperthermia, hypercapnia, acidosis, muscle rigidity, rhabdomyolysis, hyperkalemia, arrhythmia and renal failure. Mortality without specific treatment is 80% and decreases to 5% with the use of dantrolene sodium. This article presents the case of a 39-year-old patient admitted to the Intensive Care Unit for malignant hyperthermia after surgery for septoplasty plus turbinoplasty.

Inhaled Anesthetics: Environmental Role, Occupational Risk, and Clinical Use

Inhaled anesthetics have been in clinical use for over 150 years and are still commonly used in daily practice. The initial view of inhaled anesthetics as indispensable for general anesthesia has evolved during the years and, currently, its general use has even been questioned. Beyond the traditional risks inherent to any drug in use, inhaled anesthetics are exceptionally strong greenhouse gases (GHG) and may pose considerable occupational risks. This emphasizes the importance of evaluating and considering its use in clinical practices. Despite the overwhelming scientific evidence of worsening climate changes, control measures are very slowly implemented. Therefore, it is the responsibility of all society sectors, including the health sector to maximally decrease GHG emissions where possible. Within the field of anesthesia, the potential to reduce GHG emissions can be briefly summarized as follows: Stop or avoid the use of nitrous oxide (N2O) and desflurane, consider the use of total intravenous or local-regional anesthesia, invest in the development of new technologies to minimize volatile anesthetics consumption, scavenging systems, and destruction of waste gas. The improved and sustained awareness of the medical community regarding the climate impact of inhaled anesthetics is mandatory to bring change in the current practice.

Inhaled sedation with sevoflurane in critically ill children during extracorporeal membrane oxygenation

Sedation can be challenging in critically ill children. Inhaled anesthetics such as sevoflurane have proved to be useful in difficult or long-term sedation. However, its use in children out of the operating room is still limited and little is yet known about its use in patients undergoing ECMO with no previous reports in children. The objective is to assess the effectiveness and safety of sevoflurane during ECMO in two pediatric patients. Sedation was successfully achieved in both patients, and patients' contribution to breathing was possible even with deep sedation. There were not any side effects during sevoflurane treatment or after withdrawal.

Inhalation of low-dose desflurane prevents the hemodynamic instability caused by target-controlled infusion of remifentanil and propofol during laparoscopic gynecological surgery: A randomized controlled trial

The objective of the present study was to determine whether the addition of inhaled desflurane is superior to remifentanil-propofol total intravenous anesthesia (TIVA) alone in patients undergoing laparoscopic gynecological surgery. A total of 60 patients who were scheduled to undergo laparoscopic gynecological surgery were prospectively enrolled and randomly allocated to receive either propofol-remifentanil (PR group; n=30) or combined propofol-remifentanil and low-dose desflurane (PRD group; n=30) for the maintenance of anesthesia. Hemodynamics [mean arterial pressure (MAP); heart rate (HR)], recovery parameters and complications were recorded. The results of the present study indicated that the addition of desflurane significantly reduced the amount of propofol and remifentanil that was administered in the PRD group, compared with that in the PR group. MAP and HR were significantly higher at T3 (5 min post-pneumoperitoneum), but significantly lower at T4 (removal of pneumoperitoneum needle) and T5 (post-operation immediately) in the PR group, compared with the PRD group. Moreover, MAP and HR were significantly altered at multiple time points within the PR group; however, they were relatively stable in the PRD group. There were no significant differences in the recovery parameters and complications between the two groups. In conclusion, combining low-dose desflurane with PR may represent an efficient anesthesia regimen to prevent the hemodynamic instability of TIVA in patients undergoing laparoscopic gynecological surgery.

The implementation of low-flow anesthesia at a tertiary pediatric center: A quality improvement initiative

INTRODUCTION

Anesthesia machines have evolved over the years to excel in delivering low-flow anesthesia (<1 L fresh gas flow) in a closed-circuit system, with the obvious benefits being decreased costs and reduced emissions of greenhouse gases. At a pediatric hospital that provides over 25 000 anesthetics a year, a quality improvement project was initiated with the aim of decreasing the amount of sevoflurane used per anesthetic by 20% over the course of a year.

METHODS

Three Plan-Do-Study-Act cycles involving gathering comparative data, departmental education, improvement updates on our huddle board, and intraoperative confirmation rounds were completed. The bottles of sevoflurane used and the total number of anesthetics performed were collected each month. To account for the fluctuation of anesthetic cases per month, a metric of "Anesthetics Performed per Bottle of Sevoflurane Used" was created.

RESULTS

Compared to a prior twelve-month period, the Anesthetics Performed per Bottle of Sevoflurane Used were higher with a mean increase of 25%. The bottles of sevoflurane used per month was lower with a mean decrease of 20%. The carbon footprint of our sevoflurane use was also decreased and extrapolated over a year, and the decrease was equivalent to 70 000 miles driven, over 3,200 gallons of gasoline consumed, or over 31000 pounds of coal burned.

CONCLUSION

A QI initiative aimed at changing the practice of delivering at least 2L fresh gas flow to delivering a low-flow anesthetic has been a successful value-added enhancement to our pediatric anesthesia practice.

Successful management of hypothermic cardiopulmonary bypass in a malignant hyperthermia susceptible patient

Malignant hyperthermia (MH) is a potentially lethal reaction in those that are genetically predisposed, frequently triggered by inhaled anesthetics. MH is often difficult to diagnose because it is accompanied by signs and symptoms that are shared with other disorders. The diagnosis is further obscured in cardiac surgical patients, as the signs of MH can be masked by the cardiopulmonary bypass circuit (CPB) and the use of induced hypothermia. In this case-report, we describe the successful anesthetic management of a 65-year-old MH-susceptible female, confirmed via caffeine halothane contracture test, with aortic regurgitation and ascending aortic dilatation who underwent a Bentall procedure. We have also identified certain key measures for the safe anesthetic management of these patients.

The Role of Inhaled Anesthetics in Tumorigenesis and Tumor Immunity

Inhaled anesthetics are widely used for induction and maintenance of anesthesia during surgery, including isoflurane, sevoflurane, desflurane, haloflurane, nitrous oxide (N₂O), enflurane and xenon. Nowadays, it is controversial whether inhaled anesthetics may influence the tumor progression, which urges us to describe the roles of different inhaled anesthetics in human cancers. In the review, the relationships among the diverse inhaled anesthetics and patient outcomes, immune response and cancer cell biology were discussed. Moreover, the mechanisms of various inhaled anesthetics in the promotion or inhibition of carcinogenesis were also reviewed. In summary, we concluded that several inhaled anesthetics have different immune functions, clinical outcomes and cancer cell biology, which could contribute to opening new avenues for selecting suitable inhaled anesthetics in cancer surgery.

Adjunct Therapies for Refractory Status Asthmaticus in Children

Asthma exacerbation is a common reason for children to present to the emergency department. If primary therapies fail to halt the progression of an asthma flare, status asthmaticus often leads to hospital, and potentially ICU, admission. Following the initial administration of inhaled β agonists and systemic corticosteroids, a wide array of adjunct medical therapies may be used to treat status asthmaticus. Unfortunately, the data supporting the use of these adjunct therapies are often unclear, conflicting, or absent. This review will present the physiologic basis and summarize the supporting data for a host of adjunct therapies, including ipratropium, intravenous β agonists, methylxanthines, intravenous and inhaled magnesium, heliox (helium-oxygen mixture), ketamine, antibiotics, noninvasive ventilation, inhaled anesthetics, and extracorporeal membrane oxygenation. Finally, we present a suggested care map for escalating to these therapies in children with refractory status asthmaticus.

Postoperative Cognitive Dysfunction in the Elderly: A Review Comparing the Effects of Desflurane and Sevflurane

PURPOSE

The incidence of postoperative cognitive dysfunction (POCD) remains a relatively common complication in the elderly following surgery. Use of anesthesia for surgery might precipitate certain cognitive alterations. The purpose of this review is to address the impact of two volatile anesthetic agents, desflurane and sevoflurane, on POCD.

DESIGN

The focus of this review was on postoperative recovery and complications using two anesthetic agents.

METHODS

Several databases including PubMed and Cochrane were searched from the date of inception. The search words POCD, elderly, general anesthetics, desflurane, and sevoflurane were used and the search was limited to human, randomized clinical trials, and English.

FINDINGS

The findings show no difference in the emergence time between sevoflurane and desflurane and the incidence of POCD.

CONCLUSIONS

No definitive conclusion can be drawn about the type of anesthetic used and its relation to occurrence of POCD. However, the information presented is crucial, which can help to improve anesthetic usage and patient safety.

Anesthetic synergy between two n-alkanes

OBJECTIVE

N-butane and n-pentane can both produce general anesthesia. Both compounds potentiate γ-aminobutyric acid type A (GABA_A) receptor function, but only butane inhibits N-methyl-d-aspartate (NMDA) receptors. It was hypothesized that butane and pentane would exhibit anesthetic synergy due to their different actions on ligand-gated ion channels.

STUDY DESIGN

Prospective experimental study.

ANIMALS

A total of four Xenopus laevis frogs and 43 Sprague-Dawley rats.

METHODS

Alkane concentrations for all studies were determined via gas chromatography. Using a Xenopus oocyte expression model, standard two-electrode voltage clamp techniques were used to measure NMDA and GABA_A receptor responses in vitro as a function of butane and pentane concentrations relevant to anesthesia. The minimum alveolar concentrations (MAC) of butane and pentane were measured separately in rats, and then pentane MAC was measured during coadministration of 0.25, 0.50 or 0.75 times MAC of butane. An isobole with 95% confidence intervals was constructed using regression analysis. A sum of butane and pentane that was statistically less than the lower-end confidence bound isobole indicated a synergistic interaction.

RESULTS

Both butane and pentane dose-dependently potentiated GABA_A receptor currents over the study concentration range. Butane dose-dependently inhibited NMDA receptor currents, but pentane did not modulate NMDA receptors. Butane and pentane MAC in rats was 39.4±0.7 and 13.7±0.4 %, respectively. A small but significant (p<0.03) synergistic anesthetic effect with pentane was observed during administration of either 0.50 or 0.75×MAC butane.

CONCLUSIONS

Butane and pentane show synergistic anesthetic effects in vivo consistent with their different in vitro receptor effects.

CLINICAL RELEVANCE

Findings support the relevance of NMDA receptors in mediating anesthetic actions for some, but not all, inhaled agents.

A review of the use of adjunctive therapies in severe acute asthma exacerbation in critically ill children

Asthma is a common and potentially life threatening childhood condition. Asthma involves not only chronic airway remodeling, but may also include frequent exacerbations resulting from bronchospasm, edema, and mucus production. In children with severe exacerbations, standard therapy with β2-agonists, anti-cholinergic agents, oxygen, and systemic steroids may fail to reverse the severe airflow obstruction and necessitate use of adjunctive therapies. These therapies include intravenous or inhaled magnesium, inhaled helium-oxygen mixtures, intravenous methylxanthines, intravenous β2-agonists, and intravenous ketamine. Rarely, these measures are not successful and following the initiation of invasive mechanical ventilation, inhaled anesthetics or extracorporeal life support may be required. In this review, we discuss the mechanisms and evidence for adjunctive therapies in the setting of severe acute asthma exacerbations in children.