Preface
Clinical Guidelines for the Prevention of Aspiration
Particulate-free fluids
1) Women without obstetric complications are allowed to drink moderate amounts of clear fluids during labor and delivery in the delivery room.
2) In the case of elective cesarean delivery, such women should begin to abstain from drinking 2 hours before induction of anesthesia.
3) Clear liquids include water, fruit juices without pulp, soda drinks, clear tea, coffee without dairy products, sports drinks, etc. Avoidance of particulate objects within the liquid is more important than the volume of liquid ingested for the prevention of aspiration.
4) For women with additional risk factors for aspiration (e.g., morbid obesity, diabetes, difficult airway), or who are at risk for cesarean delivery (e.g., uncertain fetal heart rate abnormalities), fluid intake needs to be further restricted on an individual basis.
Solid foods
Solid food intake should be avoided during labor and delivery, and women undergoing elective surgery (cesarean delivery or postpartum tubal ligation) should be strictly fasted for 6-8 hours before anesthesia.
Pharmacological prophylaxis (acid reducers, H2 receptor antagonists and gastrodia).
The anesthesiologist should administer non-granular acid reducers, H2 antagonists, and/or gastrodia to prevent aspiration at the appropriate time (the medication needs time to work) before the procedure (i.e., cesarean section, postpartum tubal ligation).
Question1: Fasting is required for labor and delivery analgesia in U.S. hospitals, with a maximum of coffee or ice without milk. Traditionally, Chinese women are encouraged to eat, as the birth of a child requires a lot of physical energy. How is fasting good?
A: Historically, as seen in the statistics from 1952-1985 in the United Kingdom, malabsorption accounted for more than 50% of all deaths from anesthesia. The American Society of Anesthesiologists Medical Malpractice Claims Database study also found that obstetric patients were at high risk for medical claims due to vomiting, difficult airway in general anesthesia, and malpractice due to high/all spinal anesthesia.
Fasting and abstinence from food and drink is not due to labor analgesia, but rather to reduce maternal mortality. Rather, of the top 5 reasons discussed for the decline in both absolute and relative malpractice deaths after 1985 in the United Kingdom, the widespread use of intralesional analgesia and anesthesia emerged as the leading factor. The establishment and reinforcement of clinical initiatives for fasting and abstinence from food and drink was also one of the reasons. The other three causes were; 1) acid-producing agent prophylaxis, 2) rapid induction techniques for general anesthesia, and 3) training of anesthesiologists. The contribution of obstetric anesthesia development to this problem can be seen in this. However, there were still 3 maternal deaths by inadvertent aspiration in the UK from 1994-2008 national statistics. In China today, where obstetric anesthesia is not yet widespread, these histories are very important as a cautionary tale.
The blanket abstinence from food and drink when entering the labor and delivery room has recently been called into question in Western countries where intralesional labor analgesia/anesthesia is widely practiced. This is especially true for the abstinence from drinking. Given the rather mundane nature of nausea and vomiting during labor, the inability to fully predict who is truly low risk in the delivery room, the possibility of emergency cesarean delivery at any time in case of emergency, and the fact that most women without intravesical labor analgesia are under general anesthesia, starting fasting after labor initiation is an important measure to prevent malpractice, especially fatal malpractice.
The principle is to give only clear and bright drinks, thirsty mouth with ice cubes (this is estimated to be difficult for Chinese people to accept). And use 5% sugar saline 250 ml/hr intravenous rehydration. Some hospitals or birthing centers also allow women to drink non-particulate beverages, such as sports drinks. If the likelihood of cesarean delivery is estimated to be high, or if the woman is at high risk, she will be strictly fasted from food and drink.
Freshly fed expectant mothers are not contraindicated for labor analgesia, but once they enter the delivery room, they begin fasting as prescribed.
The negative impact of energy depletion or starvation ketosis on maternal and infant clinical outcomes is of great concern. Based on the results of the 2013 Cochrance meta-analysis, there was no difference in clinical outcomes of interest, including in patient satisfaction. We are not yet well aware of the hyperglycemia of diabetic mothers given large amounts of high-energy substances, especially carbohydrates, during labor, for example, where the fetus is hyperglycemic and hyperinsulinemia occurs. Whether hyperglycemia, which occurs in the neonate as a result of a lagged regression of hyperinsulinemia and disruption of maternal sugar supply after birth, also occurs in nondiabetic mothers and infants. A surprising result was found in a randomized double-blind study in the Netherlands: the rate of cesarean delivery was 2.9 times higher in mothers who consumed sugar water than in the abstinent group. Historically, intraoperative sugar infusion for energy supply was considered. Then it was found that high sugar and mortality/complication rates were strongly correlated and now sugar-containing intravenous fluids are not given. Surgery is an emergency procedure for the body, and delivery may be as well. Of course, it is better to have individualized medicine. Excitingly, with improvements in ultrasound technology, transabdominal gastric emptying testing gives us new hope.
The reduction in maternal energy consumption with intralesional labor analgesia has also made this much easier.
There are no national statistics on this in either the United States or China. This may make it easy to drop the ball on maternal deaths from inadvertent aspiration. It is recommended that the practice of Western countries that routinely abstain from food and water for low-risk women who deliver by cesarean section, but not clear, grain-free beverages, and high-risk women who deliver by cesarean section, contribute to maternal safety. In the meantime, further examination of this approach or study of individual medical approaches to better address this clinical problem. (See below for details)
Question2: Should every woman in labor abstain from food and drink throughout?
A: According to the latest guidelines of the American Society of Anesthesiologists in 2007 and the American College of Obstetricians and Gynecologists in 2009, strict fasting is no longer considered necessary for every woman in labor.
However, it is still necessary for high-risk women. Low-risk women need only fasting and can drink clear beverages. Much remains to be determined, for example, whether maternal fasting needs to be limited to the beginning of the active phase, etc., and remains to be answered by research.
Question3: Should I fast as soon as labor starts, or should I fast during labor analgesia? Is it contraindicated for labor analgesia in pregnant women who have already eaten?
A: Fasting and water control should be initiated at the moment of labor onset. Pain and/or the use of opioids have been found to slow down gastric emptying. Fasting and water control is not for labor analgesia, but for maternal safety. No one can be sure which woman will have an uneventful delivery until labor is complete. However, a full stomach is not a contraindication to labor analgesia, as long as it is not used as an exception.
Question 4: It is often said that a pregnant woman should be treated as having a full stomach even if she has fasted for 8 hours before the operation; but why is the fasting rule for elective caesarean section in China mostly 6 hours?
Answer: Usually, 6 hours means that the patient has used a diet with very little protein and fat content, while 8 hours is for those who have eaten large amounts of fish and meat.
Question5: What is a dregs-free drink? Is it possible to give a little rice soup to a woman with an upset stomach?
Answer: A dregs-free drink is a clear, transparent drink that does not contain any dregs or floating particles. Water, clear fruit juice, carbonated drinks, carbohydrate drinks, sports drinks, tea, clear coffee (without milk), etc. The beverages should be free of protein, fat, and fiber. Milk, freshly squeezed juice, yogurt, etc. are not dregs-free beverages. Rice soup with suspended particles inside is not a dregs-free drink, and accidentally inhaling it into the lungs will be very dangerous. You can drink sports drinks, Red Bull, dregs-free cinnamon soup, etc.
Question6: How many clear beverages can a woman allow?
A: According to a study, women who had a low-risk cesarean section started drinking 500 ml and then 500 ml every 3-4 hours, and no accumulation of stomach contents was seen on ultrasound.
Question7: Why should antacids be given even to women who deliver by cesarean without general anesthesia?
A: There are many non-deterministic factors in obstetrics itself during cesarean delivery and even after delivery. For example, postpartum hemorrhage caused by various reasons.
surgical malpractice, differences in obstetrician skills, etc., all of which require a longer operative time or are so difficult that intravertebral anesthesia cannot be accommodated. From the perspective of anesthesia, the cases of conversion to general anesthesia are: 4-13% epidural, 0.5-4% lumbar anesthesia cannot meet the needs of cesarean delivery; higher than chest 2 high spinal anesthesia or full spinal anesthesia complications resulting in impaired ventilation, loss of laryngeal return protection of the airway, cardiovascular problems require the transition to general anesthesia; even in the process of doing intralesional anesthesia, the situation changes requiring immediate cesarean delivery, etc. Also, cesarean delivery under intraspinal anesthesia with no sedation while awake is a huge psychological pressure on the mother. It is not uncommon for a woman to lose control mid-operation and be converted to general anesthesia. Therefore, this answer is already self-explanatory. As we always say, in the anesthesia world, a backup plan is always needed.
Question8: What is the significance of taking sodium citrate and citrate combination for cesarean women in the United States? What can be used instead of sodium citrate and citrate? What are the effects of gastrofacial and ranitidine? Can ondansetron prevent vomiting and aspiration?
A: Citrate combination is a non-granular acid preparer (granular acid preparers should be avoided), which can neutralize the retained fluid in the stomach. It is taken orally 30mL each time (containing 3g of sodium citrate + 2g of citric acid). There are other similar ones, such as 0.3 equivalent of sodium citrate, Elka-Seltzer effervescent tablets, and optionally 5% sodium bicarbonate 45 mL. Gastroflucan is used to promote gastric emptying, and ranitidine reduces acid secretion and raises the pH of gastric juice. Proton pump inhibitors can be used as an alternative to H2 receptor blockers. Ondansetron is used to prevent and treat postoperative nausea and vomiting. It has not been used to prevent malabsorption. The prevention of aspiration is hoped for by reducing gastric contents and decreasing gastric acidity. Drugs such as ondansetron are more likely to keep the stomach contents “in the stomach”.
Question9: What should we do if a woman is unwilling or refuses to control her diet and water during labor?
Answer: First of all, after the widespread implementation of intrauterine labor analgesia, the impression of high consumption will slowly fade away. With a patient-first medical mindset, it is the responsibility of the health care provider to explain the pros and cons of a medical intervention in detail. The vast majority of women can understand that this is for their safety. This happened in two hospitals on the China trip, and by explaining it, two women who had previously refused diet control were very conscientious about complying with the rule. Once they learned that it was about their lives (which became: to die or to eat?), the problem was solved. The problem was solved.