Resident Readiness General Surgery (45 page)

3.
Hypovolemia is common in the postoperative patient and is a result of intraoperative fluid losses, ongoing sensible and insensible fluid losses, and fluid shifts. This is the most likely cause of Mr. Patel’s hypotension. He has several factors contributing to an overall net negative fluid balance: inadequate maintenance fluids, NPO, and an open abdominal operation. The next step in managing Mr. Patel’s hypovolemia should start with a 1 L bolus of resuscitative fluid—again 0.9% normal saline or lactated Ringer’s solution. If the patient has congestive heart failure, then you should give fluid more judiciously, generally 250 to 500 cm
³
at a time. An adequate response should include resolution of tachycardia and a return to the patient’s baseline blood pressure. If an adequate response is not seen after the first fluid bolus, a repeat 1 L bolus should be given. You may also consider raising the maintenance IV fluid rate.

While hypovolemia is the most common cause of postoperative hypotension, analgesia is another common cause. Narcotics cause peripheral vasodilation and may also be accompanied by a depressed mental status and decreased sympathetic tone. Proper management of this patient depends on the severity of hypotension, but withholding additional narcotic administration until the patient’s blood pressure returns to normal is the first step. In an emergency, reversal agents such as naloxone are also indicated. Epidural analgesia is another common cause of postoperative hypotension because it contains a solution of local anesthetic (eg, bupivacaine) by itself or mixed with a narcotic (eg, hydromor-phone or fentanyl). These medications can anesthetize the efferent sympathetics of the spinal cord and cause peripheral vasodilation and therefore hypotension. Initial management includes decreasing or temporarily stopping the infusion
of pain medication as well as judicious administration of IV fluids. You should alert your Anesthesia colleagues, who can readjust the infusion when the hypotension has resolved.

While less common, postoperative β-blockade can be yet another cause of postoperative hypotension. Note that, in contradistinction to hypovolemia and analgesics, β-blockers not only decrease blood pressure but also prevent normal reflex tachycardia. Once again, initial treatment depends on the severity of the hypotension. Options include a 1 L bolus and, in extreme cases, reversal of β-blockade with glucagon.

Lastly, you should consider a primary cardiac cause of hypotension—even if it is rarer than the other etiologies. Surgical procedures are associated with significantly increased cardiac demand, and patients with underlying coronary artery disease are at increased risk of myocardial infarction in the immediate postoperative period. If the heart attack is significant, the reduction in cardiac output will result in shock and most likely hypotension. If you suspect a cardiac cause of the hypotension, you should obtain an EKG while you begin treatment and notify your senior resident.

In summary, hypotension is a common issue in the postoperative patient and it will be something you will come across frequently. For severe cases, treatment and diagnosis should proceed in parallel, generally with the administration of fluid and collection of at least a CBC and an EKG. Most of the time, however, the cause of the hypotension will be nonhemorrhagic hypovolemia or a drug effect. In those cases, a 1 L bolus is both a therapeutic and a diagnostic maneuver and should be your initial response for all patients without underlying heart failure. You should follow up to ensure that the patient did indeed respond. If the patient’s blood pressure does not respond to this intervention, you must broaden your differential, consider escalation of care, and notify your senior resident.

TIPS TO REMEMBER

If the patient is critically ill, initiate CPR or ACLS per standard protocols.

Be vigilant for signs of shock.

Severe hypotension in a postoperative patient should prompt a call to someone senior to you (eg, senior resident, fellow, attending).

In the absence of known or suspected heart failure, it is usually safe to give a 1 L bolus of resuscitative fluid (0.9% NS or LR).

If giving boluses of IV fluids, it is also reasonable to increase the IV fluid rate.

Adequately treating a hypotensive patient requires intervention (ie, boluses, increased infusion rates)
and
following for response.

COMPREHENSION QUESTIONS

1.
You are paged to the bedside of a recent postoperative patient with a blood pressure of 100/83. Her preoperative blood pressure was 130/91. Which of the following exam findings is most concerning?

A. Tachycardia

B. Cold big toe

C. Pallor

D. Incisional tenderness

2.
You are paged to the bedside of a recent postoperative patient with a blood pressure of 100/83. He is confused and oliguric. What is the first thing you do?

A. Check a CBC.

B. Check an EKG.

C. Do a physical exam.

D. Order a 1 L bolus of NS.

Answers

1.
C
. Pallor suggests that the patient is bleeding. Hypotension in this setting is particularly ominous and demands immediate attention.

2.
D
. While a physical exam and diagnostic tests are important, this patient is in shock and you should initiate empiric treatment while you begin your assessment. If during your assessment you determine that the patient does not need additional fluid, you can always turn it off with minimal negative consequences. Not giving fluid, however, has the potential for very large negative consequences if in fact the patient is hypovolemic.

A 57-year-old Man Who Is Postoperative With a Blood Pressure of 210/95

Eric N. Feins, MD

You are paged by the nurse in the postoperative recovery room about a 57-year-old man who underwent laparoscopic cholecystectomy 1 hour ago and is now hypertensive—BP 210/95.

On arrival to the recovery room you find the patient mentating normally. Temperature 98.5°F, HR 105, BP 190/92, RR 22, and O
₂
98% on 2 L nasal cannula. He complains of 7 out of 10 abdominal pain, for which he has already received several doses of IV hydromorphone. He denies any headache, vision changes, chest pain, or difficulty breathing. He tells you that his systolic blood pressure normally runs in the 130s and that he took his prescribed metoprolol at home this morning. His cardiopulmonary exam is notable for mild tachycardia and clear lungs. He is obese, and his abdomen is soft with mild-to-moderate tenderness in his periumbilical region, right upper quadrant, and suprapubic region.

1.
Name two possible reasons for his hypertension (HTN).