The obstetric difficult airway: if we can't predict it, can we prevent it?

Videolaryngoscopy during Urgent Cesarean Delivery: Association with Neonatal Intensive Care Unit Admission

OBJECTIVES

Parturients are at increased risk for difficult airway management with subsequent fetal complications. Videolaryngoscopy was opined to be the new standard of airway care to facilitate orotracheal intubation under urgent care conditions. We examined in parturients requiring general anesthesia for urgent cesarean delivery the association of the type of laryngoscopy technique and time required to facilitate orotracheal intubation with the incidence of subsequent neonatal intensive care unit (NICU) admission.

METHODS

Following institutional review board approval, 431 parturients aged 18 years and older who underwent urgent cesarean section requiring general anesthesia were entered into this study. Patient characteristics, maternal comorbidities, and indications for urgent cesarean delivery were collected from the electronic medical records from January 2013 to November 2018. Orotracheal intubation times by type of laryngoscopy (video or direct) and NICU admission rates also were collected. A measure of effect size, risk differences with 95% confidence intervals (CIs), were calculated for the likelihood of NICU admission by difficult orotracheal intubation and by type of laryngoscopy used to secure the airway.

RESULTS

Videolaryngoscopy as the primary type of laryngoscopy was used in 24.1% (95% CI 20.3%-28.3%) of general anesthetics. The incidence of difficult orotracheal intubation was 4.4% (95% CI 2.8%-6.7%), with a higher incidence observed with videolaryngoscopy (8.7%) than with direct laryngoscopy (3.1%) and a risk difference of 5.6% (95% CI 0.001%-11.3%). The incidence of NICU admission was 38.4% (95% CI 34.0%-43.1%). Times for successful orotracheal intubation were longer with videolaryngoscopy. Videolaryngoscopy had a higher association for NICU admission (47%) than for direct laryngoscopy (36%), with a risk difference of 11.4% (95% CI 0.01%-22.3%).

CONCLUSIONS

Videolaryngoscopy did not decrease the incidence of difficult orotracheal intubation, and it did not decrease the time associated with orotracheal intubation. Videolaryngoscopy was associated with a higher association of NICU admission. These results suggest that videolaryngoscopy does not supplant direct laryngoscopy as the standard of care for orotracheal intubation under urgent care conditions of general anesthesia for cesarean section.

Airway management and pulmonary aspiration during surgical interventions in pregnant women in the 2nd/3rd trimester and immediate postpartum - a retrospective study in a tertiary care university hospital

BACKGROUND

Pregnancy is associated with an increased risk of pulmonary aspiration during general anaesthesia, but the incidence of this complication is not well defined.

METHODS

We performed a retrospective database review in a tertiary care university hospital to determine the incidence of pulmonary aspiration in pregnant patients undergoing endotracheal intubation, with and without Rapid Sequence Induction (RSI), as well as face-mask ventilation and supraglottic airway devices. We included Patients in the 2nd or 3rd trimester of pregnancy and immediate postpartum undergoing surgical procedures. The primary endpoint was the occurrence of pulmonary aspiration.

RESULTS

Data from 2,390 patients undergoing general anaesthesia for cerclage of cervix uteri, manual removal of retained placenta, repair of obstetric laceration, or postpartum bleeding were retrospectively evaluated. A supraglottic airway device or face-mask ventilation was used in 1,425/2,390 (60%) of patients, while 638/2,390 (27%) were intubated. RSI was used in 522/638 (82%) of patients undergoing tracheal intubation, or 522/2,390 (22%) of the entire cohort. In-depth review of the charts, including 54 patients who had been initially classified as "possible pulmonary aspiration" by anaesthetists, revealed that this adverse event did not occur in the cohort.

CONCLUSIONS

In conclusion, in this obstetric surgery patient population at risk for pulmonary aspiration, supraglottic airway devices were used in approximately 60% of cases. Yet, no aspiration event was detected with either a supraglottic airway or endotracheal intubation.

[Obstetric Anesthesia]

Patient safety and reduction of possible complications are the top priorities for anesthesiologists in everyday clinical practice. Thus, interdisciplinary early assessment and optimization of patient specific medical conditions and risk factors are crucial. In obstetrics, regional anesthesia and general anesthesia are routinely being performed. To ensure maternal and fetal safety, knowledge regarding physiological changes during pregnancy is highly important. Regional anesthesia, particularly epidural analgesia, has its main field of application in the context of natural birth in the delivery room. Spinal anesthesia, as well as epidural and combined spinal-epidural anesthesia (CSE) are widely used for caesarean section. In this context, special attention should be paid to possible bleeding disorders. The combination of risk stratification and strategies to improve the patient's preoperative medical status is capable to reduce maternal and fetal complications.

Updated guideline on equipment to manage difficult airways: Australian and New Zealand College of Anaesthetists

The Australian and New Zealand College of Anaesthetists (ANZCA) recently reviewed and updated the guideline on equipment to manage a difficult airway. An ANZCA-established document development group, which included representatives from the Australasian College for Emergency Medicine and the College of Intensive Care Medicine of Australia and New Zealand, performed the review, which is based on expert consensus, an extensive literature review, and bi-nationwide consultation. The guideline (PG56(A) 2021, https://www.anzca.edu.au/getattachment/02fe1a4c-14f0-4ad1-8337-c281d26bfa17/PS56-Guideline-on-equipment-to-manage-difficult-airways) is accompanied by a detailed background paper (PG56(A)BP 2021, https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PG56(A)BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper), from which the current recommendations are reproduced on behalf of, and with the permission of, ANZCA. The updated 2021 guideline replaces the 2012 version and aims to provide an updated, objective, informed, transparent, and evidence-based review of equipment to manage difficult airways.

Analysis of Airway Management for Cesarean Delivery: Use of Risk and Proportion Differences

OBJECTIVES

Securing the parturient airway is essential during general anesthesia for cesarean delivery. The purpose of this study was to compare inferior airway views provided by the use of three commonly available laryngoscopy blades-Macintosh, Miller, or Glidescope Mac-Style-to the incidence of difficult orotracheal intubation.

METHODS

Following institutional review board approval, data from 449 electronic medical records in parturients undergoing general anesthesia for cesarean delivery were extracted during a 6-year period. The association of these blades with difficult orotracheal intubation was analyzed with risk and proportion differences measures of effect size.

RESULTS

The overall incidence of difficult orotracheal intubation was 4.2% (95% confidence interval 2.7 - 6.5%), with 6 failed orotracheal intubations (5 laryngeal mask airways rescues and 1 mask rescue). Clinically important increases in risk differences for difficult orotracheal intubation were observed in parturients with restricted mouth openings, modified Mallampati III and IV views, and reduced thyromental distances. When modified Cormack-Lehane views were grouped into III and IV versus I and II cohorts; proportion differences for difficult orotracheal intubation were dependent upon the type of blade used, with the Miller blade providing the lowest proportion difference.

CONCLUSIONS

Miller blade laryngoscopy provided the lowest proportion difference for difficult orotracheal intubation during general anesthesia for cesarean delivery. Miller blade laryngoscopy provides effective procurement of the parturient airway.