Airway Management in Aviation, Space, and Microgravity

Although medical services in aviation have evolved over years based on our understanding of physiology, advancement in monitoring technology but airway management was only recently studied with a focus on space environment. The barometric pressure of ambient air declines as altitude increases, while the volume of air in a confined space will increase according to Boyle law, and therefore oxygen concentration remains at a constant 21%. Altitude sensitive equipment includes endotracheal and tracheostomy cuffs, pneumatic anti shock garments, air splints, colostomy bags, Foley catheters, orogastric and nasogastric tubes, ventilators, invasive monitors, and intra-aortic balloon pumps. The microgravity reduces the body compensation capacity for hemorrhage, while the redistribution of the blood can affect intubation by causing facial edema. Another change is the decreased gastric emptying during aviation. Acute respiratory failure, hypoxemia or inadequate ventilation and protection of the airway in a patient with impaired consciousness are common indications for advanced airway management in aviation. Airway management requires adequate training to maintain excellent medical care during aviation. Tracheal intubation using laryngoscopy would be difficult in microgravity, since the force exerted by the laryngoscope causes the head and neck move out of the field of vision by lever effect exerted on the head and generated through the laryngoscope blade by hand generating a lack of stability, resulting in the difficulty to insert the tracheal tube. While on the ground with the help of gravity, an adequate positioning of the patient is facilitated to achieve alignment of the laryngeal, pharyngeal and oral axes, which is known as sniffing position that allows visualization of the vocal cords and supraglottic structures allowing the introduction of an endotracheal tube

Principles of Anesthesia and Airway Management in Head and Neck Surgery

This topic aims to discuss key aspects of anesthetic and airway management for head and neck surgery. Airway management is a central part of patient care and management in Head and Neck Surgery. Common challenges in Head and Neck surgery are shared airway, distorted airway anatomy due to existing pathology; risk of airway obstruction, disconnection or loss of airway intra-operatively; risk of soiling of the airway due to bleeding and surgical debris; and the potential for airway compromise post-operatively. The option for airway management technique is influenced by patient’s factors, anesthetic needs, and surgical requirements. Intubation technique necessitating either a small or large cuffed tracheal tube with a throat pack provides the highest level of airway protection Non-intubation or open airway techniques involve mask ventilation, apneic techniques, and insufflation techniques, or the use of a laryngeal mask airway. Lastly, jet ventilation techniques may be conducted via a supraglottic, subglottic or transtracheal routes. It is essential to have clear airway management plans including rescue airway strategies that should be communicated with the surgeons and patients at the earliest opportunity

Genetic and non-genetic factors impact on inr normalization in preprocedural warfarin management

Background: Annually, 10% of warfarin patients will likely need to stop warfarin prior to elective surgery to achieve a baseline international normalization ratio (INR) level (INR ≤ 1.2) at the time of the procedure. This study explores the influence of genetic and nongenetic factors on INR normalization in the Arab (major part of Near Eastern) population in preprocedural warfarin management. Methods: An observational prospective cohort study was designed to recruit Arab patients taking warfarin and scheduled for an elective procedure. Two INR readings were recorded. DNA extraction and genotyping of variants in CYP2C9*2, CYP2C9*3, CYP4F2*3, VKORC1*2, and FII (rs5896) and FVII (rs3093229) genes using real-time polymerase chain reaction were performed. Results: Data from 116 patients were included in the analysis. CYP2C9 and VKORC1 genetic variants carriers required lower maintenance dose compared to non-carriers. The analysis showed that ciprofloxacin, antiplatelet medications, and INR index (INR at visit 1) are the only factors associated with the INR decline rate. Also, the proportion of CYP2C9*3 carriers with normal INR (≤1.2) on the day of surgery was significantly lower than those with wild-type genotype (28% vs 60%, p=0.013). In addition, heparin bridging, INR target, and Sudanese nationality are significant predictors of INR normalization (≤1.2) on the day of the procedure. Conclusion: Despite the confirmed effect of genetic factors on warfarin maintenance dose, the study was not able to find a significant effect of any genetic factor on the rate of INR normalization possibly due to the small sample size. Index INR and interacting medications showed to be significant predictors of INR decline rate.This work was supported by Hamad Medical Corporation MRC [grant number 1698/2017]

Periprocedural Anticoagulation Management of Patients receiving Warfarin in Qatar: A Prospective Cohort Study

Background: The use of anticoagulant bridging remains controversial. This study was conducted to evaluate our warfarin periprocedural management in Qatar and investigate the associated clinical outcomes with such management. Methods: A prospective cohort study was designed to describe the periprocedural clinical practice in warfarin patients in Qatar and to compare clinical safety and efficacy outcomes between anticoagulant bridging and nonbridging. Results: 103 patients were recruited. Bridging occurred in 82% of the participants. No thromboembolic events were observed, while 39.1% of patients experienced bleeding events during the study period. The incidence of overall bleeding and major bleeding were numerically higher for bridging group compared to nonbridging but did not reach statistical significance ([30.6% vs 22.2%, P = 0.478] and [12.9% vs 5.6%, P = 0.375], respectively). Conclusion: Warfarin interruption and bridging are overwhelmingly used in warfarin-treated patients in Qatar. While bridging was numerically associated with increased bleeding events, there is no statistical difference in reported clinical events between bridging and nonbridging strategies