【Anesthesia hot spots】Anesthesia for bariatric surgery

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Anesthesia for bariatric surgery

Case form: Review case analysis

The patient, male, 44 years old, 180 cm tall, weighs 170 kg (body mass index [BMI], 52 kg/m2), history of hypertension, obstructive sleep apnea (OSA), and history of non-insulin-dependent diabetes mellitus is proposed laparoscopic gastric bypass surgery

The patient has a choice of laparoscopic gastric bypass surgery

Case discussion

Bariatric surgery is more effective than other methods of weight loss, and multiple studies have shown sustained weight reduction, incidence of obesity-related diseases, and overall mortality

Table 24.

Bariatric surgery includes several surgical methods, generally divided into restrictive surgery (gastric bladder gastroplasty, vertical band gastroplasty, malabsorption surgery [biliary-pancreatic bypass surgery]), or mixed surgery (gastric bypass surgery) (Figure 24.

Airway management

Morbid obesity and its common complications OSA make mask ventilation difficult

Just as the method of endotracheal intubation should be done with caution, the timing and decision of extubation should be appropriate

Anesthesia management

Pharmacokinetics differ in
morbidly obese patients.

The amount of propofol used is determined by the overall weight, not the ideal or defatted body weight
.

Due to the lipophilia of thiopental sodium and benzodiazepines, obese patients should be given larger doses
than non-obese patients.

The metabolic kinetics of opioids are more complex, with limited data suggesting that the dose of ramifentanil and fentanyl should be determined based on ideal body weight, while the dose of sufentanil can be accurately calculated
with overall weight.

The dosage of neuromuscular tissue drugs is better predicted
because non-depolarizing drugs are hydrophilic.

To avoid neuromuscular block timeout, the dose of vecuronium bromide and rocuronium bromide should be calculated
according to ideal body weight.

Although all inhaled anesthetics are safe for use in morbidly obese patients, diflurane and sevoflurane wake up faster
than isoflurane.

Dexmedetomidine, a selective alpha2 adrenal receptor agonist, can reduce the amount of opioids used during surgery, while also improving hemodynamics
during surgery.

Although epidural analgesia is technically more difficult to implement in morbidly obese patients, it can improve postoperative analgesia and can also reduce the amount
of anesthesia infiltrated at the incision site.

In short, in morbidly obese patients undergoing bariatric surgery, no anesthesia technique has more advantages than others, but when combined with OSA, it is generally believed that short-acting drugs should be used, so that recovery is faster, postoperative respiratory depression is less, and respiratory function is restored to baseline levels
faster.

Intraoperative monitoring

There is little evidence that morbidly obese patients require more cardiovascular monitoring
when performing bariatric surgery than non-obese patients.

The need for more invasive surveillance should depend on the circumstances of the comorbidities
.

Patients with pulmonary hypertension, such as OSA or hyperobesity, may need to use a ductus
pulmonary arteriosus.

Peripheral venous access is difficult to establish and a central venous catheter
is usually inserted under ultrasound guidance to facilitate blood collection.

Finally, if the blood pressure cuff is technically difficult, a ductus arteriosus
may need to be inserted.

Prognosis for patients

The overall mortality and morbidity associated with bariatric surgery are less than 1% and 15%, respectively, although open surgery is higher than laparoscopic surgery and is also elevated
in patients with multiple complications.

Multivariate analysis and risk models used to predict mortality confirm a range of risk factors
.

These include males, ages > 45 years, body mass index > 50 kg/m2, and coexisting OSA/pulmonary hypertension
.

(Table 24.
2) Postoperative mortality is mainly secondary to pulmonary embolism/deep vein thrombosis, intra-abdominal leakage/sepsis, and myocardial infarction
.

Other non-fatal complications include wound infection, pneumonia, abdominal hernia, malnutrition, and surgical events of specific procedures (e.
g.
, sac enlargement, slippage of the band).

Table 24.
2 Risk factors for postoperative complications

conclusion

For morbidly obese patients, bariatric surgery is an effective way to reduce weight loss, which can reduce the occurrence of complications and long-term mortality
.

Key information

1.
Morbidly obese patients have a high complication rate, including diabetes, hypertension, obstructive sleep apnea, gastroesophageal reflux disease and pulmonary hypertension/right heart dysfunction
.

2.
Important anesthesia considerations include the choice of use of special monitoring (usually with arterial and central venous catheters), conservative airway management, insulin therapy to maintain normal blood glucose and the choice of short-acting anesthetics
.

3.
Ventilation management during surgery should use a high concentration of inhaled oxygen and 5 to 10 cmH2O of positive end-expiratory pressure
.

Postoperative care in patients with serious complications should strengthen cardiopulmonary monitoring, and patients with OSA should use continuous positive airway pressure ventilation
.

4.
Perioperative treatment and postoperative morbidity and mortality are related to a series of risk factors and preoperative body mass index, and the incidence of postoperative complications is highest
in patients with super obesity (body mass index > 60kg/m2).

issue

1.
Which of the following diseases has the least incidence after bariatric surgery?

A.
High blood pressure

B.
Coronary heart disease

C.
Diabetes

D.
Hyperlipidemia

E.
Sleep apnea

Answer: B

2.
Which of the following drugs should be given in total weight?

A.
Fentanyl

B.
Rocuronium bromide

C.
Propofol

D.
Remifentanil

E.
Vecuronium bromide

Answer: C

3.
Which of the following patient characteristics increases morbidity and mortality after bariatric surgery?

A.
Female

B.
BMI> 40kg/m2

C.
Age> 40 years

 D.
  OSA

E.
Diabetes

Answer: D

The article | Guan Yong

Typeset | meat