UBP 5.3 (Long Form): Endocrine – Carcinoid Syndrome Flashcards
Secondary Subject -- Bowel Obstruction / Aspiration / Cricoid Pressure / Airway Blocks / Asthma / Delayed Emergence / Vaporizers / Penicillin Allergy / Pseudotumor Cerebri and Ventriculoperitoneal Shunt / CVP Waveform / Line Isolation Monitor
Intra-operative Management:
You walk into the operating room to await the patient’s arrival and the medical student asks you to explain what happens when you fill a sevoflurane-specific vaporizer wth isoflurane.
What will you tell her?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
The vaporizer is agent-specific for sevoflurane, because delivery of the appropriate concentration of agent (as indicated by the control dial setting) is calibrated for the vapor pressure of sevoflurane.
Therefore, if a sevoflurane-specific vaporizer is filled with isoflurane, the delivered concentration will be higher than expected (because the vapor pressure of isoflurane is higher than that of sevoflurane).
The danger to the patient would be compounded by the fact that isoflurane is a more potent agent than sevoflurane.
Clinical Note:
-
Vapor pressures of Volatile agents (at 20ºC)
- Sevoflurane = 160 mmHg
- Isoflurane = 240 mmHg
- Desflurane = 681 mmHg
Intra-operative Management:
The surgeon asks you to administer cefoxitin for antibiotic prophylaxis.
What do you think?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
Assuming her previous reaction was NOT an anaphylactic reaction,
I would be comfortable administering a second-generation cephalosporin such as cefoxitin (in the case of an anaphylactic reaction, the severity of the reaction justifies avoiding even a small risk of cross-reaction).
- First, less than 10% of patients who report an allergy to penicillin have a true allergy to the drug, because most of these reactions are nonimmunologic events (such as vomiting, diarrhea, or nonspecific rash) or were inappropriately attributed to the drug in the first place.
- Second, studies that suggested a very high cross-reactivity between penicillin and cephalosporins were flawed, and the true cross-reactivity is about 0.5% for first-generation cephalosporins and near zero for both second and third-generation cephalosporins.
Intra-operative Management:
What monitoring would you require?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
Given this patient’s various comorbidities, I would employ the following monitors:
- an arterial line, to facilitate rapid treatment of this patient, who is not only at risk for –
- increased intracranial pressure during the perioperative period (pseudotumor cerebri, ventriculoperitoneal shunt malfunction, pneumoperitoneum insufflation), but also
- hemodynamic instability occurring secondary to –
- hypovolemia (vomiting, diarrhea, nasogastric suctioning, and fluid-sequestration into the bowel and peritoneal cavity),
- arrhythmias (intramyocardial metastases of carcinoid tumor),
- tumor-released vasoactive mediators,
- intrinsic heart disease, and/or
- pneumoperitoneum insufflation;
- a CVP and a
-
Foley catheter to facilitate fluid management, –
- recognizing that this is of particular importance in this case in order to avoid –
- carcinoid crisis,
- cerebral ischemia (potential for elevated intracranial pressures), and
- heart failure (right ventricular dilation and 3+ tricuspid regurgitation on exam).
- recognizing that this is of particular importance in this case in order to avoid –
While a PAC would more accurately monitor left ventricular function in the presence of tricuspid regurgitation, I believe that following the pressure trends provided by the CVP monitor would be adequate in this case.
Likewise, the use of low insufflation pressures would most likely make invasive ICP monitoring unnecessary.
Intra-operative Management:
How would you induce general anesthesia?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
Given this patient’s asthma, carcinoid tumor, small bowel obstruction, and risk for aspiration (small bowel obstruction, nausea, and vomiting), my goals in inducing this patient include the following:
- rapidly and safely securing her airway;
- achieving a depth of anesthesia sufficient to prevent bronchospasm or a sympathetic response during ETT placement;
- minimizing the risk of aspiration; and
- avoiding factors that could lead to increased tumor release of vasoactive substances, such as – hypotension, catecholamine secretion, and histamine release.
Therefore, I would:
- ensure the stomach was decompressed;
- administer a B2-agonist to reduce the risk of bronchospasm;
- ensure the appropriate airway equipment was immediately available;
- provide an adequate fluid bolus;
- administer intravenous narcotics to –
- reduce the risk of bronchospasm
- (increased risk due to asthma and tumor secretion of serotonin and histamine) and
- avoid a stress-induced release of catecholamines
- (which could lead to increased tumor release of vasoactive substances);
- reduce the risk of bronchospasm
- position the patient in reverse trendelenburg
- (improves respiratory mechanics, facilitates intubation, and reduces the risk of passive regurgitation);
- apply cricoid pressure; and
- perform a rapid sequence induction, using rocuronium to rapidly provide optimum intubating conditions.
- _(**Do not use succinylcholine?? Double-check master review sheets**)_
While a slow controlled induction would be desirable to reduce the risk of catecholamine release and/or bronchospasm, I believe that the risk of aspiration for this patient with small bowel obstruction is more significant.
Intra-operative Management:
Given her risk of aspiration, would you use succinylcholine to perform a rapid sequence induction?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
I would AVOID using succinylcholine because – the fasciculations and potential histamine release associated with its administration could lead to increased release of vasoactive substances from the carcinoid tumor.
Therefore, as long as her airway exam was reassuring, I would utilize high-dose rocuronium to facilitate rapid endotracheal tube placement, recognizing that the onset of action is only slightly slower than that of succinylcholine.
Intra-operative Management:
Does cricoid pressure reduce the risk of aspiration?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
There is insufficient evidence to prove the utility of cricoid pressure in reducing the risk of aspiration.
The Sellick maneuver is performed by –
- extending the patient’s neck, providing support behind the cervical spine (i.e. pillow or hand),
- applying about 10 Newtons of pressure (equivalent to a weight of about 1 kg) to the cricoid cartilage while the patient is awake,
- increasing this to 30 N as the patient loses consciousness, and
- maintaining pressure until the cuff is inflated and proper ETT positioning is confirmed.
It is hoped that this will compress the esophagus against the cervical vertebral bodies, thereby preventing regurgitated material from entering the lungs (or at least reducing the amount).
The practice is questioned by some for several reasons:
- radiological studies have shown that in more than 90% of patients the esophagus is laterally displaced in relation to the cricoid cartilage when cricoid pressure is applied (therefore, the esophagus is not compressed against the vertebral bodies);
- cricoid pressure has been shown to reduce lower esophageal sphincter tone, potentially increasing the risk of regurgitation;
- the proper application of force has been shown to increase the difficulty of intubation in some cases (i.e. interference with insertion of the laryngoscope, degraded view of the larynx in up to 30% of patients, making external manipulation by the anesthesiologist difficult or impossible, and impeding insertion of the ETT; and
- evidence has demonstrated that many practitioners apply insufficient or excessive force during the procedure, leading to ineffectiveness and increased difficulty of intubation, respectively.
However, recognizing that the proper application of cricoid pressure may reduce the risk of aspiration in this high-risk patient, I would apply it,
with plans to reduce or eliminate the pressure if I believed it was interfering with rapid intubation (delaying the placement of the ETT places the patient at increased risk for aspiration) or if the patient began to actively vomit (failure to reduce or eliminate cricoid pressure during active vomiting risks the generation of sufficient esophageal pressure to cause esophageal rupture).
Intra-operative Management:
She tells you that the last time she was scheduled for surgery, the case was cancelled because, “they could not get the tube in her throat”.
How would this change your plan?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
Given this history, I would review her past anesthesia records and consider securing this patient’s airway while she was awake and spontaneously breathing.
Moreover, considering her high risk for aspiration, I would avoid performing a superior laryngeal nerve block and the transtracheal injection of local anesthetic, recognizing that, while these blocks may improve patient comfort, they would impair protective airway reflexes that would normally prevent the passage of regurgitated material into the lungs.
However, considering the importance of preventing a sympathetic-induced release of vasoactive substances from her carcinoid tumor (secondary to catecholamine secretion), I would provide as much airway analgesia as possible in combination with careful sedation.
Intra-operative Management:
Given the concerns about the intravascular volume loss associated with bowel obstruction, would you consider utilizing nitrous oxide to reduce the amount of volatile agent needed to maintain anesthesia?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
I would AVOID nitrous oxide during this case, recognizing that it diffuses into gas-filled cavities 34 times faster than air (primarily nitrogen) diffuses out, leading to expansion of the cavity.
Since the amount of air in the bowel is greatly increased in the setting of bowel obstruction, the use of nitrous oxide may lead to significantly increased intraluminal pressures, with subsequent bowel ischemia and necrosis.
- Clinical Note:*
- In the case of laparotomy (vs. laparoscopy), the use of nitrous oxide may complicate abdominal closure following the completion of surgery.
Intra-operative Management:
Shortly after surgery start, her blood pressure drops to 74/40 mmHg, her airway pressures increase, and you hear wheezing upon auscultation of the lungs. What is your differential?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
Given the onset of hypotension and wheezing at the same time, I would be concerned that her condition represented – **carcinoid crisis ** or an anaphylactic reaction.
However, I would keep in mind that the hypotension may, or may not, be related to the increased airway pressures and wheezing.
The hypotension could be the result of:
- hypovolemia;
- vasodilation with the induction of anesthesia;
- carcinoid crisis;
- right heart failure with reduced left heart filling (patient has right ventricular dilation with 3+ tricuspid valve insufficiency);
- cardiac arrhythmia (secondary to cardiac metastasis of carcinoid tumor or electrolyte or acid base disturbances)
- sepsis (secondary to bowel obstruction);
- tension pneumothorax (secondary to inflation of the pneumoperitoneum, central line placement, or COPD);
- anaphylaxis, or
- hypoglycemia (secondary to altered carbohydrate metabolism with carcinoid syndrome).
While the increased airway pressures and wheezing could be the result of:
- bronchospasm (secondary to her asthma),
- carcinoid crisis (tumor release of serotonin and/or histamine),
- anaphylaxis, or
- aspiration (higher risk due to bowel obstruction).
Therefore, I would immediately take steps to determine the etiology and relationship of these symptoms, in order to deliver the appropriate treatment.
Intra-operative Management:
What will you do?
(Shortly after surgery start, her blood pressure drops to 74/40 mmHg, her airway pressures increase, and you hear wheezing upon auscultation of the lungs.)
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
I would –
- ask the surgeon to cease any manipulation of the tumor,
- deflate the pneumoperitoneum,
- provide 100% oxygen,
- hand ventilate,
- confirm a sinus rhythm,
- evaluate the end-tidal CO2,
- examine her skin for hives (consistent with anaphylaxis) or flushing (consistent with carcinoid crisis or anaphylaxis), and
- auscultate the lungs to identify a tension pneumothorax and evaluate air movement.
I would then look at the CVP to determine whether her hypotension was due to right ventricular dysfunction or hypovolemia
(increasing CVP implies right ventricular dysfunction; decreasing CVP implies hypovolemia).
Then, if I did not think this was a tension pneumothorax or worsening right heart failure, I would – administer a fluid bolus, phenylephrine, octreotide, and diphenhydramine.
If none of these interventions were helping, I would place a TEE and consider administering epinephrine (to treat anaphylaxis, septic shock, or bronchospasm), vasopressin, or aprotinin (the latter two may be used to treat refractory hypotension occurring secondary to carcinoid crisis).
Intra-operative Management:
Would you give epinephrine to a patient with carcinoid syndrome?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
If I suspected anaphylaxis, septic shock, or bronchospasm that was refractory to other treatment, I would consider giving epinephrine.
However, this would be a risk/benefit decision since the administration of an exogenous catecholamine would carry the risk of inducing or worsening a carcinoid crisis.
Post-operative Management:
The patient is slow to wake following the discontinuation of anesthesia.
What is your differential for the delayed emergence of this patient?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
Given this patient’s history of carcinoid tumor and pseudotumor cerebri,
my differential would include – elevated serotonin levels (associated with delayed emergence) and elevated intracranial pressure, with the latter resulting from malfunction of her ventriculoperitoneal shunt.
Considering the physiologic disturbances associated with bowel obstruction, my differential would also include – acid-base and electrolyte abnormalities.
Finally, I would consider those causes that are associated with a routine anesthetic, such as – prolonged neuromuscular blockade, residual anesthetic, and/or significant hypothermia.
Post-operative Management:
You extubate the patient and are taking her to the ICU. The medical student is watching the CVP waveform and asks you to explain how tricuspid regurgitation (TR) affects the waveform.
What would you say?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
In the presence of tricuspid regurgitation,
the central venous pressure tracing usually exhibits a prominent cv-wave and an absent x-descent.
In the healthy heart, the c-wave reflects elevation of the tricuspid valve during early ventricular systole,
the v-wave reflects venous return against a closed tricuspid valve, and
the x-descent occurs with the downward displacement of the tricuspid valve during systole.
Regurgitation into the right atrium during systole and an increased right atrial and ventricular end-diastolic volume, result in a prominent cv-wave and an abolished x-descent on the central venous pressure tracing.
Post-operative Management:
Later that evening, she is showing radiographic findings consistent with aspiration.
What is the pathophysiology of aspiration pneumonitis?
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
The aspiration of gastric material can cause damage to surfactant-producing cells and the pulmonary capillary endothelium, with the subsequent development of atelectasis, pulmonary edema, alveolar hemorrhage, and pulmonary hypertension (the latter occurs secondary to hypoxic pulmonary vasoconstriction).
Signs and symptoms include – arterial hypoxemia (the earliest and most reliable sign of aspiration pneumonitis), tachypnea, wheezing, tachycardia, coughing, cyanosis, and bronchospasm.
Radiographic findings may take up to 6-12 hours to develop.
Post-operative Management:
Would you administer prophylactic antibiotics?
(Pt shows radiographic findings consistent with aspiration.)
- (A 5’3”, 78 kg, 47-year-old female is scheduled for laparoscopic bowel resection of a carcinoid tumor that is obstructing her bowel.*
- PMH: She was brought to the emergency room earlier in the morning with nausea, vomiting, fever, and abdominal pain. Her medical history is significant for asthma, 30 years of tobacco use, and pseudotumor cerebri, for which she has a ventriculoperitoneal shunt. She also adds that, for the past several months, she has been experiencing chronic diarrhea and occasional “bad hot-flashes”.*
- PSH: She has never had surgery.*
- Allergies: Penicillin gives her a rash.*
- PE: Vital Signs: HR = 88, BP = 128/84, R = 12, T = 36.8ºC*
- Airway: Mallampati II*
- Heart: RRR, 3/6 pansystolic murmur best heard at the left sternal border*
- Lungs: CTAB*
- Abdominal: Abdominal distension and hepatomegaly*
- Extremities: Minimal edema noted in the lower extremities*
- Radiography: Upright/Lateral CXR: Diaphragmatic elevation*
- Supine/Upright Abdominal X-ray: Small bowel is dilated with air/fluid levels*
- Echocardiogram: Right ventricular dilation & tricuspid valve insufficiency with 3+ regurgitant flow)*
While I would not routinely administer prophylactic antibiotics, I would consider it in this case, because this patient with small bowel obstruction may have aspirated feculent gastric contents, increasing her risk of pulmonary infection.
Of course, I would keep in mind her history of penicillin allergy when selecting the appropriate antibiotics (need to cover anaerobic and gram-negative bacteria).
Routine prophylactic antibiotic therapy is NOT recommended following non-feculent aspiration because, not only can it lead to drug-resistance and superinfection, but also because it has not been proven to reduce mortality or secondary infection rates.
Therefore, antibiotics should only be administered when:
- the patient demonstrates a bacterial infection based on culture and sensitivity testing,
- there is a high likelihood of gram-negative or anaerobic organisms (such as occurs in the setting of bowel obstruction), or
- the patient’s clinical course fails to improve, or worsens, after 2-3 days.
