La cesarean section with general anesthesia It's a topic that often generates a lot of questions and a certain amount of apprehension among pregnant women. These days, regional anesthesia (spinal or epidural) is the norm, allowing the mother to be awake and witness the birth of her baby. However, there are situations where general anesthesia is still necessary or even the safest option.
Although general anesthesia has been used less in obstetrics in recent decades, They remain a fundamental pillar In emergencies, when there are contraindications for neuraxial anesthesia, or when regional blocks fail, a thorough understanding of what the procedure entails, its risks and benefits for both mother and newborn, and what recent scientific evidence tells us, helps in making more informed decisions and reducing unnecessary fears.
What is general anesthesia during a cesarean section and when is it used?
In a cesarean section under general anesthesia, the mother is totally asleep and unconsciousShe feels no pain and is unaware of what is happening during the procedure, and her breathing is controlled by intubation and mechanical ventilation. This contrasts with neuraxial blocks (epidural or spinal), in which the woman remains awake but pain-free from the waist down.
International guidelines and obstetric anesthesia societies recommend prioritize regional anesthesia General anesthesia is preferred whenever possible, primarily due to the increased risk of difficult intubation and aspiration of gastric contents in pregnant women. However, even with these recommendations, approximately 0,5-1% of cesarean sections are still performed under general anesthesia in large referral hospitals.
In a large-scale follow-up study of more than 15.000 cesarean sections performed at a tertiary hospital, it was observed that the vast majority of cases of general anesthesia were due to emergency cesarean sections These procedures were used when it was deemed that there was insufficient time to administer a spinal or epidural block. They were also used when there were formal contraindications to regional anesthesia (severe coagulation disorders, severe bleeding, infections at the puncture site, certain neurological conditions) or when the patient categorically refused the puncture.
Another typical scenario is the failure of neuraxial anesthesiaIf spinal or epidural block is insufficient or asymmetric and cannot be corrected with additional doses, the intervention should continue with general anesthesia and endotracheal intubation to ensure maternal comfort and safety.
Therefore, although its use is decreasing, general anesthesia in cesarean sections remains an essential tool, which should be reserved for well-selected situations and operate following very strict protocols.
General anesthesia versus regional anesthesia: benefits and risks
To honestly compare the general anesthesia with neuraxial This involves considering both the maternal experience and the health outcomes for both mother and baby. The choice should not be based solely on preferences, but also on the available evidence regarding complications and outcomes.
Regarding the mother's experience, a key point of regional anesthesia is that it allows be awake and have skin-to-skin contact. Very early contact with the newborn, including seeing and hearing their first cry, is associated with better breastfeeding rates and emotional benefits, and is an important added value for many women.
However, meta-analyses comparing both techniques reveal interesting nuances. Neuroaxial anesthesia has been shown to be associated with more maternal nausea and vomitingThese effects are likely related to the frequent hypotension following spinal anesthesia. In contrast, general anesthesia has a higher incidence of intraoperative blood loss and chills, although many studies show no significant differences in immediate recovery.
Regarding the newborn, several analyses have evaluated the Umbilical cord pH and Apgar scoresIn some studies, spinal anesthesia was associated with a slightly lower umbilical pH than general or epidural anesthesia, but the difference was minimal and of questionable clinical relevance. More relevant are the large population-based studies that showed that, in emergency settings and with already depressed fetuses, general anesthesia was associated with a greater need for advanced resuscitation and neonatal intubation, as well as a lower 5-minute Apgar score.
It is worth clarifying that in these studies there is a clear severity biasWe tend to use general anesthesia in the most critical cases, with the worst initial fetal condition, so it is difficult to separate what part of the worst outcome is really due to the type of anesthesia and what part to the urgency and severity of the condition.
Maternal mortality and morbidity with general anesthesia in cesarean section
For decades it was repeated that general anesthesia in cesarean sections implied a maternal mortality is much higher to that of regional anesthesia. This was largely due to times when airway control, monitoring, and available drugs were much more limited than they are now.
The most recent data paint a different picture: with modern techniques, maternal mortality attributable to general anesthesia during cesarean section has been reduced to levels practically comparable to the regionalwith ratios around 1,7 and wide, overlapping confidence intervals. In other words, in trained hands and with current protocols, the risk of maternal death directly linked to the type of anesthesia is very low.
Where differences are still noticeable is in the maternal morbidityRegional anesthesia is consistently associated with less intraoperative bleeding, a lower rate of surgical site infection, less postoperative pain, and somewhat shorter hospital stays. A large population-based study identified an approximately four-fold increased risk of wound infection in women undergoing cesarean section under general anesthesia compared to those who received neuraxial anesthesia.
Some authors point out that part of this difference could be due to the fact that many cesarean sections under general anesthesia are performed in emergency contextThis is especially true when surgical preparation (asepsis, time for antibiotic prophylaxis, etc.) is less meticulous. It has also been suggested that the vasodilation produced by neuraxial blockade improves tissue perfusion and could reduce the risk of infection.
In women with severe preeclampsia, a large study showed that general anesthesia was associated with a higher risk of cerebrovascular accident In subsequent years, compared to neuraxial techniques, this finding suggests that extreme caution should be exercised with general anesthesia in this subgroup, where the hypertensive response to intubation and extubation can be especially dangerous.
Long-term effects on the mother and baby (including mental health)
Beyond the immediate outcomes, attempts have been made to assess whether the type of anesthesia can influence the child neurodevelopment or maternal mental health In the medium and long term. The results are interesting, although not yet definitive.
A cohort study that followed more than 5.000 children for five years compared the risk of learning disorders three groups were compared: vaginal delivery with regional anesthesia, cesarean section with general anesthesia, and cesarean section with neuraxial anesthesia. Children born by cesarean section with neuraxial anesthesia had the lowest incidence of learning disorders, while those born by vaginal delivery with regional block and those born by cesarean section with general anesthesia showed similar, slightly higher rates.
These findings align with concerns, stemming from animal and pediatric studies, that early exposure to general anesthetics It could alter synaptic density in a rapidly developing brain. Currently, there are no firm conclusions about the actual clinical impact of these alterations in humans, but experts recommend caution regarding prolonged or repeated exposure at very young ages.
More recent evidence has emerged regarding maternal mental health. A large study conducted in the United States, involving more than 34.000 women who underwent a cesarean section, found that general anesthesia was associated with a increased risk of postpartum depression with need for hospitalization, as well as a higher probability of suicidal ideation or self-harm.
The researchers suggest that this could be related to the inability to perform immediate skin-to-skin contact and the experience of initiating breastfeeding in the first few hours, as well as the subjective feeling of having been absent at the time of birth. All of this, combined with possible obstetric complications that led to the choice of general anesthesia, could contribute to increased emotional vulnerability in the postpartum period.
On the other hand, a recent review published in Anesthesiology, which pooled data from 36 clinical trials and nearly 3.500 cesarean sections, concluded that general anesthesia appeared to be safe for mother and baby Overall, there was no clear increase in major complications or the need for neonatal intensive care, although there were slight differences in parameters such as Apgar scores and immediate respiratory support.
Practical advantages and disadvantages of general anesthesia in cesarean section
From a technical point of view, general anesthesia has a number of very clear advantages in the obstetric context. Among their advantages are the speed of implementation (ideal in emergencies), the low failure rate when performed correctly, absolute control of the airway and ventilation, and a greater capacity to manage hemodynamics in complex situations.
It also allows combining, in the same surgical procedure, other simultaneous interventions that may be necessary for the mother, since the entire body is under anesthesia. In cases such as eclampsia with seizures, the airway and central nervous system control provided by general anesthesia can be critical for maternal survival.
On the other hand, there are the well-known disadvantages. A pregnant woman's physiology favors... difficult airwayMucosal edema, breast enlargement, sometimes limited cervical mobility, and almost always a higher body mass index. All of this, combined with the need for rapid intubation, increases the risk of failed or complicated intubation.
Added to this is the danger of aspiration of gastric contentsSince a pregnant woman should always be considered to have a "full stomach" from the second trimester until 24 hours postpartum, the combination of delayed gastric emptying, increased intra-abdominal pressure, and relaxation of the lower esophageal sphincter makes regurgitation more likely. If this occurs during a loss of consciousness, gastric contents can enter the airways and cause severe chemical pneumonitis.
Other relevant disadvantages include the risk of consciousness during anesthesia (intraoperative awakening) if the depth of anesthesia is insufficient, excessive uterine relaxation produced by some inhalational agents (which may favor bleeding) and possible respiratory or neurological depression of the neonate due to the transplacental passage of the drugs used.
Pre-assessment, preparation and monitoring of the patient
Before considering general anesthesia for a cesarean section, the anesthesiologist must perform a full assessment This should include a detailed medical history, a focused physical examination, and a specific airway assessment. Even in urgent situations, it's worth investing a few seconds in this assessment, as it can make all the difference in a complicated intubation.
Aspects such as mouth opening, thyromental distance, neck mobility, and Mallampati classification are reviewed. The latter correlates with the visualization of the glottis described by the Cormack-Lehane scale during direct laryngoscopy, and both are useful clinical tools for suspecting a potentially difficult airway.
Regarding pharmacological preparation, all pregnant women are considered to be at risk of aspiration, so efforts are made to administer, when time allows, a non-particulate antacid (for example, oral sodium citrate), an intravenous H2 antagonist (ranitidine), and a prokinetic agent such as metoclopramide. Proton pump inhibitors such as omeprazole and drugs that accelerate gastric emptying have also been studied. Although direct evidence on reducing aspiration is limited, they do raise the pH and reduce gastric volume, which likely lessens the severity of aspiration should it occur.
Whenever possible, a good caliber (16-18 G) venous access is ensured for administer fluids and medication rapidly. Minimum monitoring includes continuous electrocardiogram, pulse oximetry, non-invasive blood pressure, and capnography, the latter being key to confirming correct intubation and adjusting ventilation to avoid both hyperventilation (which can compromise uteroplacental perfusion) and hypoventilation.
In cases of higher risk (severe preeclampsia, heart disease, massive hemorrhage, etc.) advanced monitoring may be added: arterial lines for continuous invasive pressure, central venous catheter, diuresis measurement, neuromuscular relaxation monitor or anesthetic depth indices such as BIS, which help reduce the risk of intraoperative awakening.
Anesthetic technique: preoxygenation, induction and rapid intubation
One of the pillars of general anesthesia in obstetrics is the adequate pre-oxygenationPregnant women have lower functional residual capacity and higher oxygen consumption, which causes them to desaturate very quickly during any period of apnea. Therefore, they are asked to breathe 100% oxygen for several minutes before induction.
Different techniques have traditionally been compared: normal breathing for three minutes, eight deep breaths in one minute, or four deep breaths in 30 seconds. The first two achieve higher saturation levels and prolong the time to desaturation in prolonged apnea. In an obstetric emergency setting, many teams opt for the eight deep breaths in one minutebecause they balance efficiency and speed.
Position also matters. Placing the pregnant woman in semi-sitting position (30-45º) during preoxygenation and induction increases functional residual capacity and improves apnea tolerance, which is especially relevant in obese patients. Furthermore, the uterus is laterally tilted to the left (by tilting the table or manually moving it) to avoid aortocaval compression, which can cause marked hypotension and compromise uteroplacental blood flow.
Induction of general anesthesia in cesarean section is usually performed in rapid sequence: hypnotic drugs and muscle relaxants are administered while applying pressure on the cricoid cartilage (Sellick maneuver) to reduce the risk of regurgitation. The goal is to lose consciousness, intubate, and inflate the endotracheal tube cuff as soon as possible, ventilating with 100% oxygen and without excessive positive pressure manual ventilation before sealing the airway, to limit the risk of gastric insufflation.
Among induction drugs, thiopental was the standard for years, with doses of 3-7 mg/kg. It is known that moderate doses Doses below 4 mg/kg have little depressant effect on the neonate, while high doses may be associated with poorer neonatal adaptation. In many countries, its availability has decreased and it has been replaced by propofol, which is used at somewhat lower doses than in the general population (around 1,5-2 mg/kg) due to the greater sensitivity of pregnant women and its dose-dependent hypotensive effect.
Other options include ketamine, which is very useful in cases of hypovolemia or shock because it tends to maintain blood pressure, although its sympathomimetic effect makes it less advisable in severe preeclampsia. Midazolam has been used occasionally, but its significant transplacental passage It can cause neonatal depression and, although it is reversible with flumazenil, its use as the sole induction hypnotic in cesarean section is becoming less and less frequent.
Muscle relaxants, inhalational gases and other adjuvants
In the rapid sequence of a cesarean section, a muscle relaxant is recommended to provide excellent intubation conditions in a very short timeFor decades the reference choice has been succinylcholine, an ultra-rapid onset and short duration depolarizing agent, which allows spontaneous recovery of breathing to occur in a few minutes if intubation fails and the patient was well pre-oxygenated.
Rocuronium, at high doses (around 1,0-1,2 mg/kg), offers similar intubation conditions within one minute, and has the advantage that we now have a specific antagonist, the sugammadexwhich can reverse neuromuscular blockade very quickly. This makes it an attractive alternative when succinylcholine is contraindicated, always considering the cost and the need to have the antidote available if a difficult airway is anticipated.
Following intubation, anesthesia is typically maintained with a volatile inhalational agent (sevoflurane, isoflurane, desflurane) in combination with oxygen, sometimes with nitrous oxide. A minimum alveolar concentration (MAC) is targeted to ensure the patient does not regain consciousness, but without reaching a level of excessive uterine relaxation that promotes atony and bleeding. In general, a MAC target of around 0,7, adjusted with the help of depth monitors such as the BIS, is considered a reasonable balance.
Nitrous oxide It has been used as an adjunct to reduce the need for halogenated anesthetics and decrease the risk of intraoperative awareness in emergency cesarean sections, although not all teams use it routinely. Electroencephalographic studies have shown that, contrary to previous beliefs, pregnancy does not significantly increase cerebral sensitivity to volatile anesthetics, reinforcing the importance of monitoring depth to avoid underdosing.
Among the contributing factors, the role of magnesium sulphateIt is widely used in preeclampsia, reducing the need for propofol and other drugs, improving the response to noxious stimuli, and helping to control the hypertensive response. However, its use must be cautious, because an overdose can cause respiratory depression and excessive neuromuscular blockade.
Ultra-short-acting opioids, such as remifentanil, are valuable tools for attenuating the hemodynamic response to laryngoscopy and intubation, especially in preeclamptic patients at risk of hypertensive crisis. However, they cross the placenta to a large extent and can cause neonatal respiratory depression If administered as a bolus before birth, their use must be very carefully measured and coordinated with the neonatology team.
Specific complications: difficult airway, aspiration, and intraoperative awareness
Probably the complication that most worries the anesthesiologist in a cesarean section with general anesthesia is the failed intubationThe incidence of impossible or very difficult intubation in obstetrics is higher than in the general population, at approximately 0,4% (1 in 250 obstetric general anesthetics). The risk of rapid desaturation and aspiration necessitates a well-defined plan.
Every center that performs cesarean sections should have a specific algorithm for obstetric airway managementThis protocol usually includes: limiting the number of intubation attempts, optimizing head and neck positioning, using aids such as stylets or videolaryngoscopes, always prioritizing oxygenation over intubation at all costs, and resorting to supraglottic devices (laryngeal mask, especially ProSeal or Supreme models) if mask ventilation is difficult.
If, despite everything, a scenario arises where "intubation is not possible, ventilation is not possible," techniques for [the following] must be rapidly adopted. surgical access to the airwaysuch as emergency cricothyroidotomy or, ultimately, an urgent tracheostomy. These cases are exceptional, but the key is to recognize failure early and not insist on multiple intubation attempts that only worsen oxygenation and increase edema.
Another serious complication is chemical pneumonitis from aspiration of gastric contents. Although pharmacological prophylaxis and protective maneuvers have reduced its incidence, it remains a potential cause of severe maternal morbiditySystematic reviews have shown that antacids, H2 antagonists, and proton pump inhibitors raise gastric pH and decrease volume, but studies are less clear regarding a direct translation into a reduction of aspiration episodes, which does not prevent their widespread use in countries with strict obstetric protocols.
Intraoperative awareness is another very real concern in cesarean section under general anesthesia. It is defined as the conscious recollection of events that occurred during anesthesia and can leave significant psychological sequelae, including post traumatic stress disorderPregnant women are at greater risk than the general population, especially during the period between induction and birth, because we tend to reduce drug doses to minimize the impact on the fetus.
In past decades, rates of awareness as high as 26% were reported in cesarean sections under general anesthesia. Today, thanks to improved protocols and the use of monitors like the BIS, this incidence has been reduced approximately one hundredfold, to around 0,26%. Even so, careful planning is crucial. temporality of drugs (when each one is administered, in what dose, and how the anesthesia is reinforced right after birth) to avoid periods of underdosing.
The role of simulation and training in obstetric anesthesia
Although general anesthesia for cesarean sections is less common than it once was, that's precisely why many anesthesiologists are taking risks. less to this technique in daily practice and may lose fluency in critical situations such as difficult airways or unexpected drug reactions.
To keep skills sharp, there is an increasing reliance on... clinical simulation In obstetric settings: workshops with high-fidelity mannequins, training in failed intubation algorithms, eclampsia simulations requiring urgent general anesthesia, etc. This type of training allows rehearsing communication with the obstetric and neonatology team, decision times, and the application of protocols without putting real patients at risk.
In addition, various groups recommend establishing specific records of cesarean sections performed under general anesthesia, with data on indications, complications, and short- and long-term maternal and neonatal outcomes. These registries help identify areas for improvement, update protocols, and provide local evidence to complement large international studies.
For pregnant women, it is very helpful that information about the different types of anesthesia (spinal, epidural, general) be included in prenatal education. Being able to discuss any doubts with the anesthesiologist or the obstetric team, and knowing the real advantages and risks Understanding each option and knowing that general anesthesia, when properly managed, can be a safe alternative reduces anxiety and facilitates shared decision-making when the time comes.
The choice between regional and general anesthesia for cesarean section is based on a combination of factors: the specific clinical situation, urgency, contraindications, the team's experience, and the mother's preferences, provided that safety is not compromised. Current evidence indicates that neuraxial anesthesia remains the preferred technique due to its lower morbidity, but also that general anesthesia, when administered with rigorous protocols and by trained teams, is a valuable tool. valid and necessary which should not be demonized and about which women should have clear, realistic information based on quality studies.