UBP 2.4 (Long Form): Endocrine – Pheochromocytoma Flashcards
Secondary Subject -- α-blockade & ß-blockade/α-Methylparatyrosine/ Hypercarbia Differential - Laporascopic Surgery/Malignant Hyperthermia/Malignant Hypertension/ Subcutaneous Emphysema/Post-operative Conjunctival Edema/Post-operative Nausea and Vomiting
Intra-operative Management:
Would you give a fluid bolus prior to induction?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Recognizing that this patient’s elevated hematocrit is consistent with hypovolemia, I would perform a careful examination to evaluate his volume status, and provide fluids as indicated.
While some patients with pheochromocytoma are hypovolemic secondary to chronically increased SVR, many patients are normovolemic, especially those who have been receiving alpha-blockers for a sufficient time to normalize systemic vascular resistance and intravascular volume (about 2 weeks).
My goal would be – to correct any hypovolemia, recognizing that inadequate volume replacement places the patient at increased risk for:
- significant hypotension following –
- induction,
- establishment of a pneumoperitoneum, and
- vascular isolation of the tumor;
- gas embolism and paradoxical embolism (the latter is more of a risk when there is a patent foramen ovale), complications associated with laparoscopic surgery; and
- post-operative nausea and vomiting (occurs in 40-75% of patients following laparoscopic surgery).
However, recognizing that this patient may be at risk of developing congestive heart failure with overly aggressive volume replacement, I may choose to use invasive monitoring (CVP or PAC) to guide fluid replacement.
Intra-operative Management:
What monitoring would you require?
Would you place a pulmonary artery catheter?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
GIven the potential for significant variations in blood pressure due to inadequate volume replacement, excessive catecholamine release, vascular isolation of the tumor, and/or the hemodynamic effects of pneumoperitoneum (increased abdominal pressure and hypercapnia lead to reduced cardiac output, increased arterial pressures, and increased systemic and pulmonary vascular resistances),
I would require direct arterial pressure monitoring (may also be beneficial due to the poor correlation between PaCO2 and PETCO2 in patients with cardiopulmonary disturbances – i.e. COPD, cardiomyopathy, etc.),
an ECG with a V5 lead, and
a Foley catheter (to decompress the bladder for laparoscopy and aid in fluid management),
in addition to standard ASA monitors.
Given this patient’s complaints of decreased energy and the 47% ejection fraction noted during echocardiography, combined with the potential for significant cardiovascular stress with establishment of a pneumoperitoneum (increased SVR & PVR; decreased cardiac output),
intra-operative fluid shifts, and catecholamine secretion during tumor manipulation (increased afterload), I would also require a central line combined with a pulmonary artery catheter or transesophageal echocardiography (TEE) to aid in fluid management and treatment with vasoactive drugs.
However, I would keep in mind that the increased thoracic pressure associated with pneumoperitoneum complicates the interpretation of central venous and pulmonary artery pressure measurements, making them less reliable.
Clinical Note:
- The insertion of an orogastric or nasogastric tube is also required for laparoscopy in order to decompress the stomach (improves visualization and reduces the risk of regurgitation and/or gastric perforation).
- Intermittent sequential compression stockings should be utilized to reduce the risk of thromboembolic complications (potentially increased risk secondary to the lower limb venous stasis associated with increased intra-abdominal pressures).
Intra-operative Management:
How will you induce this patient?
(*note – in answering this question, Set the stage for Why you are doing what you are doing… Mention your goals & concerns.. But Answer the question…)
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
My goals in inducing this patient with pheochromocytoma, COPD, and GERD, include:
- avoiding drugs that may directly stimulate the pheochromocytoma and/or exacerbate the effects of catecholamine excess;
- achieving a sufficient plane of anesthesia to prevent bronchospasm or sympathetic stimulation;
- avoiding hypoxia and hypercarbia, which may stimulate the sympathetic nervous system; and
- avoiding pulmonary aspiration.
Therefore, I would:
- ensure appropriate intravascular volume replacement, aspiration prophylaxis (avoid metoclopramide as it may cause tumor secretion of catecholamines), bronchodilator therapy, and adequate preoxygenation;
- apply cricoid pressure and place him in reverse trendelenburg position to facilitate rapid intubation and inhibit passive regurgitation; and
- perform a rapid sequence induction using intravenous lidocaine and fentanyl to blunt the sympathetic response to laryngoscopy, propofol to ensure an adequate plane of anesthesia, and rocuronium to provide rapid muscle relaxation (Avoid Succinylcholine – mention this up front! – succinylcholine can cause histamine release and/or abdominal fasciculations, which may result in the release of catecholamines from the tumor).
Intra-operative Management:
Could this case proceed with regional anesthesia alone?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Possibly, but I don’t believe this would be optimal.
Although regional anesthesia may prevent sympathetic discharge in the area of blockade, it does not block the sympathetic activity associated with tumor release of catecholamines.
Additionally, regional anesthesia may provide inadequate analgesia to alleviate the discomfort of abdominal distension and diaphragmatic irritation associated with the creation of the pneumoperitoneum.
Also, in the presence of regional anesthesia and a pneumoperitoneum, this patient with COPD may be unable to generate adequate spontaneous ventilation to prevent hypercarbia, which can result in an undesirable increase in sympathetic tone.
Intra-operative Management:
Which medications should be avoided during the case?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Drugs that should be avoided, if possible, during the case include:
- those that stimulate tumor cells, such as succinylcholine (abdominal fasciculations) and histamine releasing drugs (i.e. morphine and atracurium);
- those that result in increased sympathetic activity, such as atropine, pancuronium, ketamine, and ephedrine; and
- those that sensitive the myocardium to catecholamines, such as halothane.
Droperidol, metoclopramide, and ephedrine should also be avoided if possible since they have all been associated with significant hypertension when administered to patients with pheochromocytoma.
Any drugs that are sympathomimetic should be avoided.
Ephedrine is avoided because of its indirect effects – you want to use direct-acting agents such as phenylephrine for hypotension.
Anticipate this question – what drugs will you use in pheochromocytoma for hypotension?
Intra-operative Management:
Ten minutes after establishment of the pneumoperitoneum, the arterial blood gas shows a PaCO2 of 54 mmHg.
What do you think may be going on?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Assuming CO2 was used to establish the pneumoperitoneum, this hypercarbia most likely reflects the normal increase in arterial CO2 that occurs during the first 15-30 minutes following peritoneal insufflation (primarily due to absorption of CO2 from the peritoneal space, but ventilation/perfusion mismatch secondary to patient positioning, cardiopulmonary disturbances, and/or increased abdominal pressures may contribute).
However, other potential causes should be considered including:
- inadequate ventilation,
- CO2 emphysema (extraperitoneal insufflation of CO2);
- capnothorax (movement of CO2 into the thorax through natural or iatrogenic communications between the peritoneal cavity and the pleural and pericardial sacs),
- CO2 embolism (usually occurs with the direct insufflation of large amounts of CO2 into a blood vessel),
- pneumothorax secondary to alveolar rupture (risk increased due to smoking history, central line placement, and hyperventilation to maintain normocarbia),
- aspiration (pulmonary edema, bronchospasm, atelectasis → ventilation/perfusion mismatching → hypercarbia),
- malignant hyperthermia (no known previous exposure to triggering agents), and
- other causes of ventilation/perfusion mismatch (i.e. hypotension, congestive heart failure, COPD, arrhythmia).
An examination of the oropharynx for gastric material, verification of proper endotracheal tube placement and bilateral breath sounds, a focused physical exam, and a review of the patient’s blood pressure, ECG, end-tidal CO2, and an ABG would help to narrow the differential.
Intra-operative Management:
10 minutes after establishment of the pneumoperitoneum, the arterial blood gas shows a PaCO2 of 54 mmHg.
What would you do?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
(Try to shorten this answer)
Recognizing that hypercapnia can stimulate an undesirable release of catecholamines,
- I would ensure proper ETT placement and adequate ventilation;
- auscultate the chest for equal and bilateral breath sounds;
- examine his oropharynx for signs of gastric material; and
- evaluate his blood pressure, cardiac rhythm, end-tidal CO2, temperature, and ABG.
Next, I would examine the patient for signs of:
- subcutaneous emphysema (increased PETCo2, increased PaCo2, and subcutaneous crepitating of the head, neck, and face);
- capnothorax (decreased pulmonary compliance, increased airway pressures, increased PETCo2, and increased PaCo2);
- CO2 embolism (initially the PETCo2 is decreased due to decreased cardiac output, increased PaCO2, hypotension, hypoxia, aspiration of foamy blood from the central venous catheter, increased pulmonary artery pressure, increased central venous pressure, millwheel murmur, cyanosis, cardiac arrhythmia, and right heart strain on ECG);
- tension pneumothorax secondary to alveolar rupture (decreased PETCo2 secondary to decreased cardiac output, increased PaCO2, hypotension, hypoxia, hyper-resonance to percussion over the left thorax, contralateral tracheal shift, distended neck veins, and abnormal motion of one hemidiaphragm as observed by the surgeon);
- congestive heart failure (increased PaCo2 secondary to decreased cardiac output, pulmonary edema, jugular venous distention, increased CV and PAC pressures); and
-
malignant hyperthermia (generalized rigidity, changes in blood pressure, arrhythmias, increased temperature, peripheral mottling, cyanosis, hyperkalemia, myoglobinuria, sweating, and a mixed metabolic and respiratory acidosis).
7.
Intra-operative Management:
Since this patient has never had surgery before, would you consider giving dantrolene?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
In the absence of other signs of malignant hyperthermia, such as – generalized rigidity, increased temperature, peripheral mottling, rhabdomyolysis, and a mixed metabolic and respiratory acidosis,
I would NOT immediately treat with dantrolene.
However, I would continue to assess the patient for any additional signs of MH reaction and treat accordingly.
Intra-operative Management:
The case is proceeding and you notice the patient’s urine output is low.
What would you do?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Recognizing that transient oliguria often occurs during laparoscopic surgery secondary to the hypercarbia and increased intra-abdominal pressures
- (urine output may be reduced by 50% due to –
- decreased cardiac output,
- sympathetic-induced release of catecholamines, and/or
- increased secretion of antidiuretic hormone),
I would cautiously provide volume replacement after considering fluid losses, urine output, invasive monitoring data (although this may be less reliable in the presence of pneumoperitoneum), and the amount of residual intraperitoneal saline.
I would be very careful to avoid excessive fluid replacement in this patient with cardiomegaly, decreased energy levels, and an ejection fraction of 47% (increased risk for congestive heart failure).
Assuming the patient’s oliguria were the result of increased abdominal pressures and hypercarbia, I would expect his renal function to quickly return to normal following the release of the pneumoperitoneum.
Intra-operative Management:
You notice puffiness around her chest and neck that exhibits crepitus.
What would you do?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
This clinical picture is consistent with subcutaneous emphysema, a complication that may occur with pneumothorax secondary to pneumoperitoneum formation (i.e., capnothorax) or alveolar rupture (this patient is at increased risk due to pulmonary disease, recent central line placement, and hyperventilation).
Therefore, I would check for increased PETCO2 and/or PaCO2 and assess the patient for possible pneumothorax (i.e. chest x-ray or bedside ultrasound).
If examination suggested that the subcutaneous emphysema was secondary to CO2 insufflation, I would discontinue insufflation, hyperventilate the patient, and, following the resolution of his hypercapnia, have the surgeon recreate the pneumoperitoneum using a lower insufflation pressure.
Finally, given this patient’s pulmonary disease (COPD), I would delay extubation at the end of the case and continue mechanical ventilation until the hypercapnia was completely resolved, in order to avoid unnecessary post-operative increases in the work of breathing.
Intra-operative Management:
The surgery proceeds and the patient’s blood pressure increases dramatically to 205/108 mmHg.
What will you do?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
After verifying the blood pressure, I would ask the surgeon to cease any manipulation of the tumor;
ensure adequate ventilation, normocapnia, sinus rhythm, and a sufficient depth of anesthesia; and
review hemodynamic data provided by the CVP and PAC.
If the hypertension persisted, I would consider administering one of the following antihypertensive medications:
- sodium nitroprusside
- (a potent direct vasodilator that has a rapid onset and a short duration of action),
- phentolamine
- (a competitive alpha-blocker and direct vasodilator;
- onset and duration of action or prolonged as compared to sodium nitroprusside;
- associated with tachyphylaxis and tachycardia),
- nitroglycerine
- (may cause tachycardia),
- esmolol,
- labetalol
- (possibly useful for predominantly epinephrine-secreting tumors secondary to its relatively greater B-blocking activity), or
- magnesium sulfate
- (inhibits catecholamine release from the adrenal medulla and peripheral nerve terminals;
- a direct vasodilator;
- reduces the sensitivity of alpha-receptors to catecholamines).
- Alternatively, I could initiate a continuous infusion of – nicardipine,
- as this drug’s selective action on arterial resistance vessels (avoiding a potentially deleterious reduction in venous return) is desirable for patients with cardiac disease undergoing laparoscopy (pneumoperitoneum causes decreased cardiac output and increased systemic and pulmonary vascular resistance).
If his hypertension remained refractory, I would consider administering a mixture of antihypertensive drugs such as sodium nitroprusside, phentolamine, esmolol, and diltiazem.
The use of short acting antihypertensive drugs is often desirable to avoid exacerbating the significant hypotension that often develops following tumor vein ligation.
Intra-operative Management:
The blood pressure is normalized and the surgeon ligates the vein supplying the tumor.
Shortly thereafter, the patient’s blood pressure drops to 74/46 mmHg.
What do you think is going on?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
The timing of this hypotension makes the isolation of the tumor, with a subsequent decrease in plasma catecholamines (the 1/2 life of epinephrine and norepinephrine are about 1-2 minutes), the most likely etiology.
Other factors that often contribute to this hypotension include –
- residual alpha-blockade,
- hypovolemia (i.e. inadequate preoperative volume replacement, blood loss, and intraoperative fluid loss),
- catecholamine-induced cardiomyopathy, and
- anesthetic-induced cardiovascular depression.
Of course other potential causes of hypotension, independent of tumor isolation, should also be considered, such as –
- congestive heart failure,
- vagal stimulation (manipulation of viscera),
- arrhythmia,
- cardiac ischemia,
- massive blood loss, and
- pneumothorax.
Post-operative Management:
You notice the patient has significant conjunctival edema.
Would you delay extubation?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
There are two reasons I would delay extubation.
- First, his conjunctival edema (possibly due to trendelenburg positioning and/or volume overload) may be associated with laryngeal edema, placing him at increased risk for loss of airway following extubation.
- Second, given his chronic obstructive pulmonary disease (i.e. FEV1 = 75% predicted; hyperinflated lungs on CXR) and the intraoperative development of subcutaneous emphysema, I would want to continue mechanical ventilation until his hypercapnia had completely resolved in order to avoid excessively increased work of breathing.
Therefore, I would extubate the patient when his hypercapnia resolved and I could elicit a leak around the endotracheal tube following balloon deflation.
While his conjunctival edema may simply represent localized edema secondary to intraoperative trendelenburg positioning, it could be the result of significant fluid overload and/or more generalized edema, placing him at increased risk for – post-operative hypertension, congestive heart failure, and pulmonary edema.
Therefore, if further evaluation suggested volume overload, I would – administer a diuretic, and monitor the patient closely until he demonstrated adequate diuresis and decreased signs of fluid overload (the return of normal renal function following pneumoperitoneum release may make a diuretic unnecessary).
Post-operative Management:
While you are in the post-op area, the nurse tells you that his blood sugar is 58 mg/dL.
Why do you think his blood sugar is so low?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Patients are at increased risk of developing significant hypoglycemia following tumor removal because the drop in plasma catecholamines results in –
- increased release of insulin
- (the stimulation of alpha 2-adrenergic receptors in pancreatic beta cells by epinephrine and norepinephrine inhibits the release of insulin) and
- reduced gluconeogenesis and glycogenolysis
- (epinephrine stimulates these processes that serve to increase blood sugar).
Therefore, fluid replacement following tumor removal should include dextrose-containing solutions and the patient’s blood sugar should be monitored closely for at least 24 hours post-operatively.
Post-operative Management:
Is this patient at increased risk of postoperative nausea and vomiting?
- (A 56-year-old male presents for laparoscopic resection of an abdominal pheochromocytoma.*
- PMH: He has a history of poorly controlled hypertension, recurrent headaches, palpitations, and sweating. He complains of decreased energy for the past 6 months, and daily acid reflux that he treats with Tums. He also admits to a 30-year history of smoking.*
- PSH: The patient has never had surgery.*
- Medications: Phenoxybenzamine; Atenolol; Tums*
- PE: Vital Signs: P = 76; BP = 116/72 mmHg; R = 10; T = 37 ºC*
- Airway: Mallampati II*
- CV: RRR*
- Lungs: CTA Bilaterally*
- Lab: H/H = 17/51; Plt = 178*
- plasma catecholamines = 2200 pg/mL*
- EKG: Left axis deviation*
- CT: 2.2 cm mass in right adrenal medulla*
- CXR: Cardiomegaly, hyperinflated lungs*
- Echo: Ejection Fraction = 47%*
- PFTs: FEV1 = 75% predicted)*
Yes.
Post-operative nausea and vomiting (PONV) occurs in around 40-75% of patients following laparoscopic surgery.
This complication is thought to be the result of bowel manipulation, diffusion of CO2 into the bowel, and rapid peritoneal distension during creation of the pneumoperitoneum.
The incidence of PONV is –
- increased by the use of intra-operative opioids and
- reduced by the use of propofol anesthesia, gastric emptying, and the administration of antiemetics, such as droperidol (NOT appropriate for this case), ondansetron, dexamethasone, and transdermal scopolamine.
(Also NO Reglan for this case – it’s not appropriate.)
