Airway management for cesarean delivery performed under general anesthesia

Supreme laryngeal mask airway for cesarean section under general anesthesia: a 10-year retrospective cohort study

Background

Previous research showed the use of supraglottic airways in obstetric anesthesia. The relevant evidence of laryngeal mask airway (LMA) on maternal and neonatal outcomes is still limited. We aimed to assess the maternal and neonatal outcomes when the LMA Supreme was used for cesarean section under general anesthesia.

Methods

We included all patients who underwent general anesthesia for cesarean section between January 2010 and December 2019. Propensity score matching was used to reduce potential bias from non-random selection of airway intervention. The primary outcome was adverse maternal and neonatal outcomes defined as maternal regurgitation, aspiration, hypoxemia, and low neonatal Apgar scores. Secondary outcomes included patient admission to the intensive care unit, neonate required tracheal intubation, external cardiac massage, and admission to the neonatal intensive care unit.

Results

A total of 723 patients were included in the analysis; of whom, 221 received Supreme laryngeal mask airway (LMA group) and 502 were intubated with an endotracheal tube (ETT group). After propensity score matching, 189 patients remained in each group. No episode of regurgitation and aspiration occurred in both groups. There was no difference in the rates of Apgar score below 7 at 1 min (14.3% LMA group vs. 15.3% ETT group, OR 0.931, 95% CI 0.574 to 1.510, P = 0.772) and 5 min (3.7% vs. 4.2%, OR 0.875, 95% CI 0.324 to 2.365, P = 0.792). No difference was observed in the secondary outcomes between the two groups.

Conclusion

The LMA Supreme was not associated with higher adverse maternal and neonatal outcomes when compared to an endotracheal tube for cesarean section under general anesthesia. It might be considered an alternative to tracheal intubation in obstetric practice.

Airway management for 362 cesarean deliveries performed with general anesthesia at a Texas level IV maternal facility

At our hospital, direct and video laryngoscopy are used in airway management for cesarean deliveries performed with general anesthesia. We hypothesized that video laryngoscopy would have a higher success rate of endotracheal intubation on the first attempt compared to direct laryngoscopy. We used our electronic medical record system to search for patients who had cesarean deliveries with general anesthesia with endotracheal intubation performed in the operating room from July 1, 2017, through June 30, 2021. Totals of 186 and 176 patients had direct and video laryngoscopy for the first intubation attempts, respectively; 177 (95%) and 163 (93%) patients, respectively, had a successful intubation on the first attempt with each method. The odds ratio of successful intubation on the first attempt for video laryngoscopy was 0.64 (95% CI 0.27, 1.53; P = 0.31) compared to patients who had direct laryngoscopy. There was no statistically significant difference in Cormack-Lehane grade views of the glottis between direct and video laryngoscopy on the first attempt. In conclusion, there was no statistically significant improvement in the success rate of intubation on the first attempt when video laryngoscopy was used for patients undergoing general anesthesia for cesarean delivery.

COVID-19 critical illness in pregnancy

Although the pregnant population was affected by early waves of the COVID-19 pandemic, increasing transmission and severity due to new viral variants has resulted in an increased incidence of severe illness during pregnancy in many regions. Critical illness and respiratory failure are relatively uncommon occurrences during pregnancy, and there are limited high-quality data to direct management. This paper reviews the current literature on COVID-19 management as it relates to pregnancy, and provides an overview of critical care support in these patients. COVID-19 drug therapy is similar to that used in the non-pregnant patient, including anti-inflammatory therapy with steroids and IL-6 inhibitors, although safety data are limited for antiviral drugs such as remdesivir and monoclonal antibodies. As both pregnancy and COVID-19 are thrombogenic, thromboprophylaxis is essential. Endotracheal intubation is a higher risk during pregnancy, but mechanical ventilation should follow usual principles. ICU management should be directed at optimizing maternal well-being, which in turn will benefit the fetus.

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.

Critical Care Management of Severe COVID-19 in Pregnant Patients

Since December 2019, the coronavirus disease (COVID-19) pandemic has had a disastrous impact worldwide. COVID-19 is caused by the SARS-CoV-2 virus and was declared a pandemic by the WHO on March 11, 2020. The virus has been linked to a wide range of respiratory illnesses, ranging from mild symptoms to acute pneumonia and severe respiratory distress syndrome. Pregnant women are more vulnerable to COVID-19 complications owing to the physiological and immunological changes caused by pregnancy. According to the CDC, pregnant patients with COVID-19 are commonly hospitalized and often require admission to ICUs and ventilator support. Therefore, it is especially important for pregnant women to adhere to disease prevention measures to lower the risk of contracting the disease. In addition, the guidelines of several clinical societies and local health authorities should be followed when caring for pregnant women with suspected or confirmed COVID-19. In this review article, we discuss the epidemiology of COVID-19 during delivery, its effect on the physiological and immunological changes during pregnancy, the classification of COVID-19 severity, maternal and fetal risks, antenatal care, respiratory management, treatment/medication safety, timing and mode of delivery, anesthetic considerations, and the outcome of critically ill pregnant patients with COVID-19, as well as their post-delivery care and weaning from mechanical ventilation.

Frequency and Risk Factors for Difficult Intubation in Women Undergoing General Anesthesia for Cesarean Delivery: A Multicenter Retrospective Cohort Analysis

BACKGROUND

Estimates for the incidence of difficult intubation in the obstetric population vary widely, though prior studies reporting rates of difficult intubation in obstetrics are older and limited by smaller samples. The goals of this study were to provide a contemporary estimate of the frequency of difficult and failed intubation in women undergoing general anesthesia for cesarean delivery and to elucidate risk factors for difficult intubation in women undergoing general anesthesia for cesarean delivery.

METHODS

This is a multicenter, retrospective cohort study utilizing the Multicenter Perioperative Outcomes Group database. The study population included women aged 15-44 undergoing general anesthesia for cesarean delivery between 2004 and 2019 at one of 45 medical centers. Co-primary outcomes included the frequencies of difficult and failed intubation. Difficult intubation was defined as Cormack-Lehane view ≥3, intubation attempts ≥3, rescue fiberoptic intubation, rescue supraglottic airway, or surgical airway. Failed intubation was defined as any attempt at intubation without successful endotracheal tube placement. Rates of difficult and failed intubation were assessed. Several patient demographic, anatomical, and obstetric factors were evaluated for potential associations with difficult intubation.

RESULTS

We identified 14,748 cases of cesarean delivery performed under general anesthesia. There were 295 cases of difficult intubation, with a frequency of 1:49 (95% CI: 1:55, 1:44) (n=14,531). There were 18 cases of failed intubation, with a frequency of 1:808 (95% CI: 1:1,276, 1:511) (n=14,537). Factors with the highest point estimates for the odds of difficult intubation included increased body mass index, Mallampati score III or IV, small hyoid to mentum distance, limited jaw protrusion, limited mouth opening, and cervical spine limitations.

CONCLUSIONS

In this large, multi-center, contemporary study of over 14,000 general anesthetics for cesarean delivery, we observed an overall risk of difficult intubation of 1:49 and a risk of failed intubation of 1:808. Most risk factors for difficult intubation were non-obstetric in nature. These data demonstrate that difficult intubation in obstetrics remains an ongoing concern.

Comparison of videolaryngoscopy and direct laryngoscopy for tracheal intubation in obstetrics: a mixed-methods systematic review and meta-analysis

PURPOSE

The incidence of difficult and failed intubation is higher in obstetrical patients than in the general population because of anatomic and physiologic changes in pregnancy. Videolaryngoscopy improves the success rate of intubation and reduces complications when compared with direct laryngoscopy in adults; however, it is not known whether this extends to obstetrical surgery. The aim of this study was to examine the efficacy, efficiency, and safety of videolaryngoscopy compared with direct laryngoscopy in obstetrics.

SOURCE

Central, CINAHL, Embase, MEDLINE and Web of Science databases were searched from inception to 27 May 2020 with no restrictions. Inclusion criteria included randomized-controlled trials (RCTs), observational studies, case series, and case reports that reported the application of videolaryngoscopy to intubate the trachea in pregnant patients having general anesthesia.

PRINCIPAL FINDINGS

Overall, four RCTs with 428 participants, nine observational studies, and 35 case reports/series with 100 participants were included. On meta-analysis of three trials, the co-primary outcomes of first-attempt success rate (risk ratio, 1.02; 95% confidence intervals [CI], 0.98 to 1.06; P = 0.29; I2 = 0%) and time to tracheal intubation (mean difference, 1.20 sec; 95% CI, -6.63 to 9.04; P = 0.76; I² = 95%) demonstrated no difference between videolaryngoscopy and direct laryngoscopy in parturients without difficult airways. Observational studies and case reports underline the role of videolaryngoscopy as a primary choice when difficulty with tracheal intubation is expected or as a rescue modality in difficult or failed intubations.

CONCLUSIONS

Evidence for the utility of videolaryngoscopy continues to evolve but supports its increased adoption in obstetrics where videolaryngoscopes should be immediately available for use as a first-line device.

TRIAL REGISTRATION

PROSPERO (CRD42020189521); registered 6 July 2020.

Comparison of postoperative pulmonary outcomes in patients undergoing cesarean section under general and spinal anesthesia: A single-center audit

Introduction:

Regional anesthesia (RA), i.e., spinal or epidural anesthesia when performed for lower segment cesarean section (LSCS) provides excellent surgical conditions, avoiding manipulation of the maternal airway, maternal satisfaction, and good postoperative analgesia. However, in situations like fetal distress (fetal heart rate abnormalities), obstetric indications (abruption of placenta, antenatal placental bleeding, cord prolapse), maternal refusal for RA, contraindications to neuraxial anesthesia (anticoagulation, coagulopathy), and at times failed RA general anesthesia (GA) is administered. Several studies have demonstrated greater mortality and morbidity when LSCS is done under GA when compared to neuraxial block.

Methods:

After necessary approval, we retrospectively reviewed data over a period of 1 year (January 1, 2020–December 31, 2020) of LSCS under GA versus RA. The aim was to compare immediate postoperative complications, postoperative pulmonary complications up to 4 weeks from the time of elective and emergency LSCS under either RA or GA.

Results:

Of the 753 patients who underwent LSCS in one calendar year, there were 272 (36.12%) elective and 481 (63.87%) emergency LSCS. The number of elective LSCS under neuraxial block was 219 (29.09%) and under GA were 53 (7.03%). Emergency LSCS done under neuraxial block were 268 (35.59%) and under GA were 213 (28.28%). There were no adverse pulmonary complications at the end of 4 weeks in either group.

Conclusion:

RA provides maternal satisfaction and excellent perioperative analgesia in LSCS. Safe GA can be achieved with proper airway planning, if case is attended by at least two anesthesiologist with adequate preoperative fasting, and postoperative monitoring.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 1. Difficult airway management encountered in an unconscious patient

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the literature on airway management has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This first of two articles addresses difficulty encountered with airway management in an unconscious patient.

SOURCE

Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians, were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence was lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Most studies comparing video laryngoscopy (VL) with direct laryngoscopy indicate a higher first attempt and overall success rate with VL, and lower complication rates. Thus, resources allowing, the CAFG now recommends use of VL with appropriately selected blade type to facilitate all tracheal intubations. If a first attempt at tracheal intubation or supraglottic airway (SGA) placement is unsuccessful, further attempts can be made as long as patient ventilation and oxygenation is maintained. Nevertheless, total attempts should be limited (to three or fewer) before declaring failure and pausing to consider "exit strategy" options. For failed intubation, exit strategy options in the still-oxygenated patient include awakening (if feasible), temporizing with an SGA, a single further attempt at tracheal intubation using a different technique, or front-of-neck airway access (FONA). Failure of tracheal intubation, face-mask ventilation, and SGA ventilation together with current or imminent hypoxemia defines a "cannot ventilate, cannot oxygenate" emergency. Neuromuscular blockade should be confirmed or established, and a single final attempt at face-mask ventilation, SGA placement, or tracheal intubation with hyper-angulated blade VL can be made, if it had not already been attempted. If ventilation remains impossible, emergency FONA should occur without delay using a scalpel-bougie-tube technique (in the adult patient). The CAFG recommends all institutions designate an individual as "airway lead" to help institute difficult airway protocols, ensure adequate training and equipment, and help with airway-related quality reviews.

The use of adjunct anesthetic medication with regional anesthesia and rates of general anesthesia for 1867 cesarean deliveries from 2014 to 2018 in a community hospital

The number of cesarean deliveries performed with a general anesthetic decreased when regional anesthesia for cesarean delivery was reported to be associated with lower maternal mortality. Anesthetic adjunct administration for cesarean deliveries performed with regional anesthesia is typically not reported alongside general anesthesia rates for cesarean delivery. This retrospective study analyzed rates of general anesthesia and systemic anesthetic adjunct administration for cesarean deliveries performed under regional anesthesia at a community hospital from 2014 to 2018. We used the hospital electronic medical record system to collect data on cesarean deliveries during the study period. A total of 1867 cesarean deliveries were performed, corresponding to a cesarean delivery rate of 30.4%. Of the subjects, 104 (5.6%) received general anesthesia and 333 (17.8%) received regional anesthesia with at least one systemic anesthetic adjunct. These adjuncts included a variety of intravenous agents-midazolam (1.7%), fentanyl (5.2%), morphine (6.6%), propofol (7.9%), and ketamine (1.7%)-as well as inhaled nitrous oxide (1.4%) and sevoflurane (0.1%). These data on anesthetic adjunct administration with regional anesthesia provide clinical context for the rates of general anesthesia reported for cesarean delivery.

Rescue supraglottic airway devices at caesarean delivery: What are the options to consider?

Tracheal intubation is considered the gold standard means of securing the airway in obstetric general anaesthesia because of the increased risk of aspiration. Obstetric failed intubation is relatively rare. Difficult airway guidelines recommend the use of a supraglottic airway device to maintain the airway and to allow rescue ventilation. Failed intubation is associated with a further increased risk of aspiration, therefore there is an argument for performing supraglottic airway-guided flexible bronchoscopic intubation (SAGFBI). The technique of SAGFBI has a high success rate in the non-obstetric population, it protects the airway and it minimises task fixation on repeated attempts at laryngoscopic tracheal intubation. However, after failed intubation via laryngoscopy, there is a lack of specific recommendations or indications for SAGFBI in current obstetric difficult airway guidelines in relation to achieving tracheal intubation. Our narrative review explores the issues pertaining to airway management in these cases: the use of supraglottic airway devices and the techniques of, and technical issues related to, SAGFBI. We also discuss the factors involved in the decision-making process as to whether to proceed with surgery with the airway maintained only with a supraglottic airway device, or to proceed only after SAGFBI.

[Application of sevoflurane and laryngeal mask in cesarean section in women with heart disease]

OBJECTIVE

To compare the safety of sevoflurane anesthesia with laryngeal mask and tracheal intubation in cesarean section in women with heart disease.

METHODS

Fifty-two pregnant women with heart diseases undergoing cesarean section were randomized into laryngeal mask (LAM) group and tracheal intubation group. In LAM group, 6% sevoflurane was given at the rate of 6 L/min for induction with a maintenance sevoflurane concentration of 3%. In the intubation group, 1.5 mg/kg propofol and 1 µg/kg remifentanil were injected intravenously, and after achieving D0 with Narcotrend monitoring, 0.9 mg/kg rocuronium was injected and intubation was performed 1 min later. The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded in the two groups before anesthesia induction (T₀), at intubation or laryngeal mask placement (T₁), skin incision (T₂), and extubation or laryngeal mask removal (T₃). The surgery to fetal birth time, uterine incision to fetal childbirth time, drug discontinuation to awake time, and newborn Apgar scores were also recorded. Sevoflurane consumption and maternal comfort during hospitalization were compared between the two groups.

RESULTS

In LAM group, HR and MBP at T₁ and T₃ were significantly lower than those in the intubation group (P<0.05). The drug discontinuation to extubation time and to awaken time were significantly shorter in LAM group than in the intubation group (P<0.05), but the operation time and fetal child birth time were comparable between the two groups (P>0.05). The women in LAM group reported better physical and psychological comforts than those in the intubation group (P<0.05). The neonatal Apgar scores and the scores of health education, satisfaction with hospital environment and service were all similar between the two groups (P>0.05).

CONCLUSION

Sevoflurane anesthesia with laryngeal mask can achieve satisfactory anesthetic effects in cesarean section in women with heart disease.