Complications of Laparoscopy Case File

Complications of Laparoscopy Case File

Lydia Conlay, MD, PhD, MBA, Julia Pollock, MD, Mary Ann Vann, MD, Sheela Pai, MD, Eugene C. Toy, MD

Case 41

A 26-year-old woman presents to an outpatient surgery center for a laparoscopic excision of an ovarian cyst. The patient is very anxious and comments that she does not want to be awake. Her medical history includes asthma treated with an inhaler, and gastroesophageal reflux disease. Her only medication is albuterol, but she has not needed it for 6 months. She has no prior surgical history, no history of familial or anesthetic complications, and no allergies to medications. On examination, the patient’s height is 62 in and she weighs 75 kg. Breath sounds are clear. Airway examination reveals a Mallampati 2 classification, full range of motion of the neck, and a 3-cm thyromental distance. Her hematocrit is 37. This patient’s ASA physical status classification is ASA class II. Since she is a healthy patient undergoing a low-risk outpatient procedure, no further preoperative evaluation is required. The patient was taken to the operating room, and an intravenous placed. She was premedicated with bicitra, metoclopramide, and ranitidine for her gastric reflux, and midazolam for her anxiety. Standard monitors were placed, and anesthesia was induced uneventfully with propofol, cisatracurium, and fentanyl, and maintained with sevoflurane and 40% oxygen. The trachea was easily intubated and placed on the ventilator with a tidal volume of 650 mL and respiratory rate of 10 breaths/minute (bpm). She was then placed in a dorsal lithotomy and head-up position. Upon insufflation of the peritoneum, the patient’s peak inspiratory pressure increased from 17 to 37 cm of water. Over the next 10 minutes, the endtidal carbon dioxide measurement rose from 32 mm Hg to 44 mm Hg and oxygen saturation decreased from 98% to 94%. Blood pressure and heart rate remained unchanged.

➤ What is the differential diagnosis of hypoxia in this patient?

➤ What are the maneuvers to treat the complications in this patient?

ANSWERS TO CASE 41:

Complications of Laparoscopy

Summary: A healthy young woman undergoes an uneventful anesthetic induction for laparoscopic surgery. After change in patient position and insufflation, there is an increase in end-tidal carbon dioxide and hypoxia.

➤ Causes of hypoxia: Endobronchial intubation, kinking or dislodgement of the endotracheal tube, hypoventilation, pneumothorax, atelectasis, pneumoperitoneum, decreased cardiac output, gas embolism, and potential vascular injuries.

➤ Corrective manuevers: Administration of 100% oxygen, ensuring correct endotracheal tube placement, hemodynamic support with pressors or inotropes if needed, the addition of positive end-expiratory pressure (PEEP), and treating the etiology of hypoxia are the maneuvers required at this time.

ANALYSIS

Objectives

1. Identify the physiologic changes that can be encountered during laparoscopy.

2. List the possible complications of laparoscopy.

3. Describe the management of hypoxia and hypercarbia during laparoscopy.

Considerations

When an unexpected event occurs during an anesthetic, the first level of the differential diagnosis addresses the acuity of the problem. For example, is it a “little problem,” or a “big problem”? In this case, the patient’s hypoxemia has occurred over a 10-minute period, and her other vital signs are stable. Thus while the situation must be addressed and could be serious, it is not currently in the catastrophic category of events. Next, when hypoxemia is observed in a patient who is intubated and mechanically ventilated, it is important to differentiate an iatrogenic or mechanical cause from a patient-related medical condition. But first, the fraction of inspired oxygen is increased. Then by ventilating by hand and auscultating the breath sounds, it is possible to assess for the presence of bilateral breath sounds, the presence of wheezing, an endotracheal tube obstruction, displacement, cuff leak, and possibly, a pneumothorax. If the evaluation is unremarkable, then the ventilator and its connections should be checked. In this patient, breath sounds were clear bilaterally which implied proper endotracheal tube placement and excluded major pulmonary pathology. Oxygen saturation improved with 100% oxygen and addition of positive end-expiratory pressure (PEEP). Mechanical ventilation was resumed, with a fraction of inspired oxygen of 50% and 5 cm of water of positive endexpiratory pressure and an oxygen saturation of 98% was maintained.

Increasing the patient’s minute ventilation can usually decrease the endtidal carbon dioxide measurement. But since the pneumoperitoneum during laparoscopy often elevates peak inspiratory pressure, increasing minute ventilation is best accomplished by increasing the respiratory rate and decreasing the tidal volume for an overall increase in minute ventilation. Reducing the tidal volume may also reduce the peak inspiratory pressure, resulting in an increase in lung compliance. Increasing the respiratory rate from 10 to 16 and decreasing the tidal volume from 650 mL to 500 mL would increase the minute ventilation by 1.5 L/min, from 6.5 L/min to 8 L/min. In this case, endtidal carbon dioxide decreased from 44 mm Hg to 40 mm Hg after the increase in minute ventilation. The procedure proceeded uneventfully, and within 20 minutes of extubation, 4 mg of ondansetron was given for prevention of postoperative nausea and vomiting.

APPROACH TO

Complications of Laparoscopy

CLINICAL APPROACH

Laparoscopic surgery offers many benefits over open surgery. These include smaller incisions, less blood loss and postoperative pain, shorter hospital stay, and fewer postoperative wound infections. Performed almost exclusively by gynecologists for decades, this technique is now common for both general and genitourinary surgical procedures as well.

Laparoscopy is facilitated by insufflating gas into the abdomen. The most common gas used for insufflation is carbon dioxide, which does not support combustion as do oxygen, air, or nitrous oxide. Carbon dioxide is also more soluble than other alternatives such as helium and nitrogen, thus likely reducing the impact of a gas embolus should it occur. However, because of CO2’s solubility, there is significant absorption across the peritoneum, which often results in a mild hypercapnia.

While there are benefits to laparoscopic surgery, laparoscopy can result in profound cardiovascular and pulmonary changes in physiology. There are many factors that contribute to the hemodynamic alterations that occur during laparoscopy (Table 41–1), but the most influential are intra-abdominal pressure (IAP) and patient position. The pneumoperitoneum created for laparoscopy can compress the abdominal arterial and venous vasculature. Consequently, there is increased IAP and systemic vascular resistance (SVR)

Table 41–1 FACTORS THAT AFFECT CARDIOVASCULAR STATUS WITH PNEUMOPERITEUM

Intra-abdominal pressure Patient position Intravascular volume Volume of carbon dioxide absorbed Ventilatory technique Surgical conditions Anesthetic agent

and a decreased cardiac index. However, if insufflation pressure remains below 12 mm Hg, minimal hemodynamic consequences occur in healthy patients.

Changes in patient position also contribute to the hemodynamic consequences of a pneumoperitoneum. In the head-up position, there is decreased venous return and cardiac output due to venous pooling in the legs (in addition to the pneumoperitoneum), with up to a 50% reduction in cardiac index. In healthy patients, this is generally well tolerated, but hemodynamic instability can result in patients with preexisting cardiovascular disease, anemia, or hypovolemia. The head-down position is associated with a cephalad shift of the diaphragm, which decreases functional residual capacity and lung compliance, possibly leading to atelectasis, mild hypoxemia, and an increased peak airway pressure. Endobronchial intubation is also more likely to occur.

Absorption of the CO2 used for insufflation, in addition to hypoventilation, can result in hypercarbia. Hypercarbia, in turn, stimulates the sympathetic nervous system and can increase blood pressure, heart rate, myocardial contractility, and cause arrhythmias (tachycardia is the most common). It can sensitize the myocardium to catecholamines, setting the stage for ventricular arrhythmias. Hypercarbia can typically be overcome by increasing minute ventilation. However, if it is refractory or accompanied by hypoxemia or high airway pressures, the pneumoperitoneum should be released and insufflation attempted again at a lower intra-abdominal pressure. If complications recur, it may be necessary to convert to an open procedure. For recalcitrant hypercarbia, the possibility of malignant hyperthermia should be kept in mind.

Complications of Laparoscopy

The physiological changes that accompany laparoscopy can range from the common place and almost expected to the catastrophic and fortunately, rare. The most vulnerable time for the patient is just after the induction of anesthesia, during trocar insertion and gas inflation. Trocar insertion is a blind procedure, which can result in damage to blood vessels or vital organs such as the liver. Insufflation can cause a reduction in cardiac output which may be poorly tolerated in a patient with significant comorbidities. (Perhaps ironically, the sicker the patient, the more he or she will benefit from a minimally invasive approach.) Insufflation can also be associated with the catastrophic complication of air embolus, pneumothorax, or the development of subcutaneous emphysema. Even the more minor and expected physiologic alterations, such as decreased venous return and a decrease in FRC, may be magnified because of the continued presence of anesthetic induction agents and/or the introduction of inhalation anesthetics, clouding the differential diagnosis. During this initial portion of the surgical procedure, the anesthesiologist must be especially vigilant.

Vascular injuries can occur, chiefly during insertion of the Veress needle or trocar into major vessels such as the aorta, common iliac vessels, or inferior vena cava. If this occurs, the needle or trocar should be left in place to avoid further bleeding and help identify the site of injury and a laparotomy performed. Similarly, gastrointestinal or urinary tract injuries may occur during Veress needle or trocar insertion.

Gas embolism may cause hypotension and asystole, which occur most likely during insufflation. Gas may embolize through a tear in the abdominal wall or peritoneum or directly into a vein or organ. If embolism is suspected, insufflation should be discontinued, the patient should be placed in the left lateral decubitus position and head down to allow the gas to collect in the apex of the right ventricle, and prevent entry into the pulmonary artery. Hyperventilation will facilitate the elimination of carbon dioxide. A central venous catheter can be placed in order to aspirate the gas.

Pneumothorax has been reported during laparoscopic procedures and can occur during trocar insertion, insufflation, or dissection if associated with a tear in the visceral peritoneum, parietal pleura, or rupture of preexisting bullae. The presentation of pneumothorax during laparoscopy can be insidious, or there may be an increase in peak airway pressure, a decrease in oxygen saturation, severe hypotension, and cardiac arrest. Once this diagnosis is made, the pneumoperitoneum should be released immediately. Since carbon dioxide is rapidly absorbed, there may be no need for chest tube placement unless there is cardiopulmonary compromise. With similar mechanisms, pneumomediatinum and pneumopericardium are also possible.

Pneumoperitoneum can mask blood loss, even marked blood loss exceeding 1 L. Thus, acute blood loss must be considered in the differential diagnosis of deteriorating cardiovascular function.

Bradycardia and asystole can occur during laparoscopy, and have been attributed to vagal stimulation from the stretching of the peritoneum in the face of light anesthesia, or from a more catastrophic complication, carbon dioxide embolization. (For a more complete list of the differential diagnosis of cardiovascular collapse during laparoscopy please see Table 41–2.)

Postoperative nausea and vomiting (PONV) is a common issue addressed after laparoscopic surgery. The 5-HT3 receptor antagonists, such as ondansetron, are often effective in preventing PONV when given at the end of surgery, as well as adequate hydration and pain control.

Table 41–2 CAUSES OF CARDIOVASCULAR COLLAPSE DURING LAPAROSCOPY

Acute blood loss Cardiac tamponade Drug-related complications Dysrhythmia Excessive intra-abdominal pressure Gas embolism Myocardial dysfunction Respiratory acidosis Tension pneumothorax Vasovagal reaction

Comprehension Questions

41.1. At which point during laparoscopy are life-threatening complications most likely to occur?

A. Insertion of the trocar and insufflations of the abdomen

B. During the procedure being performed

C. After the abdomen is deflated and the CO2 removed

D. Postoperatively, in the recovery room

41.2. A 54-year-old woman is undergoing a laparoscopic cholecystectomy procedure under general anesthesia. During the procedure, the patient’s oxygen saturation decreases and peak inspiratory pressure increases. There are no breath sounds on the right side. Which of the following is the most likely diagnosis?

A. Gas embolism

B. Pneumothorax

C. Pneumomediastinum

D. Acute blood loss

E. Pulmonary aspiration

41.3. A 35-year-old woman is undergoing laparoscopy procedure for chronic pelvic pain and suspected endometriosis. During insufflation of carbon dioxide into the abdominal cavity, the patient develops hypotension and hypoxemia. Auscultation of the heart and lungs reveals a machinelike murmur. The first step in treatment for this patient should be which of the following?

A. Stop insufflating and decompress the pneumoperitoneum.

B. Place patient head up.

C. Place patient head down.

D. Place central venous catheter to aspirate gas.

ANSWERS

41.1. A. Most of the life-threatening complications of laparoscopy occur during insertion of the trocar and insufflation of the abdomen. This period follows closely the induction of anesthesia, and is a time when the anesthetist may be attending to charting. However, vigilance at this time is of paramount importance to the patient.

41.2. B. While any of the choices could result in hypoxia, the absence of breath sounds makes pneumothorax the best choice.

41.3. A. This patient likely has a CO2 embolism. In the event of gas embolus, the first response to a suspected gas embolus during laparoscopy should be to stop insufflation and decompress the pneumoperitoneum. It is also advisable to place the patient in the head-down position in an attempt to prevent the embolus from entering the pulmonary artery and attempt to withdraw gas from a central venous catheter.

Clinical Pearls

➤ Physiologic perturbations during laparoscopy may result from the pneumoperitoneum or from surgical complications.

➤ Increased intra-abdominal pressure secondary to insufflation causes increased systemic vascular resistance and decreased cardiac output, which can be exacerbated by the head-up position.

➤ Hypercarbia,hypoxia, and atelectasis may result during laparoscopy due to a decrease in pulmonary compliance and functional residual capacity.

➤ Other complications of laparoscopy include arrhythmias, hemorrhage, gas embolus, tension pneumothorax, pneumomediastinum, perforation, and postoperative nausea and vomiting.

References

Gerges FJ, Kanazi GE, Jabbour-Khoury SI. Anesthesia for laparoscopy: a review. J Clin Anesth. 2006;18(1):67-78. Joshi GP. Anesthesia for laparoscopic surgery. Can J Anesth. 2002:49(6):R1-R5. Joshi GP. Complications of laparoscopy. Anesthesiol Clin North Am. 2001:19(1):89-105. O’Malley C, Cunningham AJ. Anesthesia for minimally invasive surgery: laparoscopy, thoracoscopy, hysteroscopy. Anesthesiol Clin North Am. 2001:19(1):1-19.

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