High blood pressure in the PACU has been linked to poorer outcomes after painful surgical procedures.
According to a recent study’s results, the incidence of posto perative hypertension in patients who had undergone general anesthesia was associated with increased PACU length of stay (LOS) and pulmonary complications. Future studies evaluating blood pressure in the immediate postoperative period are needed, the authors suggested, and proposed that hypertension and its treatment might be beneficial as a novel metric in an enhanced recovery after surgery (ERAS) pathway.
“Incidence of systolic hypertension was a lot higher than we thought and more common than diastolic hypertension,” said Jordan Sharlin, MD, an anesthesiology resident at Northwestern University Feinberg School of Medicine, in Chicago.
“Laparoscopic abdominal and spine cases were associated with a higher incidence of systolic and diastolic hypertension and higher pain scores compared to open abdominal and orthopedic cases, emphasizing our original hypothesis—that pain is a driving force of hypertension after surgery.”
Possible Component of Future ERAS Pathway?
As Dr. Sharlin reported, hypertension—driven by sympathetic activity—is common after surgery and can lead to pulmonary edema and respiratory compromise. “The perception of pain releases catecholamines, and these catecholamines lead to a redistribution phenomenon that can overwhelm the heart’s functional capacity,” he said.
For the patient, hypertensive acute heart failure manifests as a rapid onset of difficulty breathing. Although implementation of an ERAS care pathway has been shown to attenuate surgical stress and accelerate patient recovery, he said, direct measures of hyperadrenergic stress are absent from current practice summaries.
“There are many components to ERAS, but prevention and treatment of PACU high blood pressure is not one of them,” Dr. Sharlin observed. “Adrenergically mediated hypertension may represent a novel care determinant in the postoperative period and ERAS pathway.”
“We hypothesize that pain is a driving factor for hypertension after surgery, so we chose to include procedures with a predicted potential for causing moderate to severe postoperative pain based on recent findings,” Dr. Sharlin said (Anesthesiology 2013;118:934-944).
As Dr. Sharlin reported at the International Anesthesia Research Society 2017 annual meeting (abstract 1410), incidence of systolic hypertension (systolic blood pressure [SBP], 140-180 mm Hg) in the PACU was 50%, whereas incidence of severe hypertension (SBP, >180 mm Hg) was 10%. Overall incidence of systolic hypertension (SBP, >140 mm Hg) exceeded that of diastolic hypertension (diastolic blood pressure [DBP], >90 mm Hg) at 60% versus 25%, respectively (n=844).
The data also demonstrated that laparoscopic abdominal and spinal cases were associated with a higher incidence of systolic and diastolic hypertension and higher pain scores (n=684) compared with open abdominal and orthopedic cases (P<0.001).
The incidence of systolic hypertension was highest for laparoscopic abdominal cases (73.6%; n=323), followed by spinal (65%; n=160), open abdominal (48.3%; n=151) and orthopedic (42.8%; n=210) cases, respectively. The incidence of diastolic hypertension was highest for spinal cases (36.9%; n=160), followed by laparoscopic abdominal (30.6%; n=323), orthopedic (17.1%; n=210) and open abdominal (13.9%; n=151) cases, respectively. Spinal cases were associated with the highest pain scores (7.67±2.35; n=136), followed by laparoscopic abdominal (7.06±2.34; n=291), open abdominal (6.74±2.71; n=111) and orthopedic cases (6.26±3.29; n=146), respectively.
High blood pressure also was associated with longer PACU LOS and postoperative pulmonary complications. Although the relationship between SBP and oxygen saturation/fraction of inspired oxygen ratio was statistically significant (P=0.031; n=501) after adjusting for age, sex, ASA physical status score, body mass index (BMI), procedure type and surgery length, additional variables—such as postoperative opioid consumption and residual neuromuscular blockade—need to be accounted for in order to strengthen the regression model, Dr. Sharlin noted.
“In our linear regression model, the two strongest predictors of postoperative pulmonary complications were age and BMI, followed by ASA score and systolic blood pressure,” Dr. Sharlin said. “Surprisingly, the relationship between surgery length and postoperative pulmonary complications did not appear to be statistically significant, which contradicts previous reports.”
In the future, the investigators intend to factor duration of hypertension into the analysis to see whether there is an additional association with PACU LOS and postoperative pulmonary complications.
Moderator of the session, Anis Dizdarevic, MD, assistant professor of anesthesiology and pain management at NewYork-Presbyterian/Columbia University Medical Center, in New York City, wondered why laparoscopic cases might be associated with more pain.
“I suspect that surgeons are more likely to flood the field with local anesthetic after surgery if it is an open incision down the middle, but they don’t frequently put local anesthetic around the laparoscopic portholes,” Dr. Sharlin said. “Even though they are minor incisions, if they’re not blocked, they can definitely cause pain.
“There could also be more blood loss in the open abdominal cases,” Dr. Sharlin added. “When compared to laparoscopic cases, it’s possible that the open cases didn’t have as much hypertension because they had lost more blood during the surgery. In the future, I would like to look at estimated blood loss and fluids given during surgery to determine whether there’s a net negative or positive balance.”