Case report: Profound hypotension associated with labetalol therapy in a patient with cerebral aneurysms and subarachnoid hemorrhage

An audit of postoperative haemodynamic stability after intraoperative labetalol administration in non-cardiac surgery patients

Anaesthesiologists commonly use intravenous labetalol to adjust patient haemodynamics during surgical procedures. Cases of profound hypotension after continuous labetalol infusions have been reported; however, there is limited evidence regarding the safety of intraoperative labetalol boluses. This audit examined the frequency of postoperative hypotension and bradycardia in 292 adult non-cardiac surgery patients treated with intraoperative labetalol boluses. Blood pressure and heart rate data were collected from the post-anaesthesia care unit and on the floor units for 24 hours after surgery. The median total intraoperative labetalol dose was 10mg. A total of 30/292 patients had all-cause postoperative hypotension within 24 hours of surgery, 26 of which had other medical or surgical precipitants. Fifteen patients developed bradycardia. There were no deaths or intensive care unit admissions attributed to labetalol. This audit demonstrates a low risk of all-cause postoperative hypotension (10%) and bradycardia (5%) after the use of small IV doses of intraoperative labetalol.

Safety of high-dose intravenous labetalol in hypertensive crisis

Purpose

The study assesses the safety of high-dose intravenous (i.v.) labetalol in adults.

Methods

This is a retrospective administrative record review of 28 hospitals in one health care system, from October 2010 through October 2015. Patients were included if they received 300 mg of i.v. labetalol within a 24-hour period. Vital signs, adverse events and cumulative medication doses were obtained for up to 24 hours while on labetalol. Adverse events were defined as any systolic blood pressure measurement less than 90 mm Hg or heart rate less than 60 beats per minute.

Results

We analyzed the records of 188 patients who received i.v. labetalol at higher than the maximum recommended dose of 300 mg. The mean dose of labetalol was 996 mg (range 300 to 4465 mg). The cumulative labetalol dose was not associated with adverse safety outcomes (p = 0.428), although eighty-one patients (44.3%) experienced adverse events. Sixty-six patients (36.5%) developed bradycardia and 34 patients (18.6%) developed hypotension. Only five patients (2.7%) required a rescue agent for refractory adverse events.

Conclusion

A retrospective review of high-dose i.v. labetalol hydrochloride with doses greater than 300 mg in 24 hours observed a high rate of bradycardia and hypotension, but the study found that these events rarely caused clinically significant hemodynamic compromise and was not statistically associated with adverse events.

Comparing Labetalol and Nitroglycerine on Inducing Controlled Hypotension and Intraoperative Blood Loss in Rhinoplasty: A Single-Blinded Clinical Trial

Background

Uncontrolled bleeding during surgery is one of the main predisposing factors for failure of the surgeon and complications following rhinoplasty. The current study aimed at comparing the effects of nitroglycerine and labetalol on the induction of controlled hypotension and bleeding volume during septorhinoplasty.

Methods

The current randomized, controlled, clinical trial enrolled 60 patients candidate for septorhinoplasty at Firoozgar hospital in Tehran, Iran, in 2 equal groups receiving either 0.1 to 1 mcg/kg/minute nitroglycerine or 2 to 4 mg/minute labetalol to achieve a mean arterial blood pressure of about 60 to 65 mmHg. In case the targeted blood pressure was not achieved, isoflurane was added. Degree of bleeding was evaluated by the volume of suctioned blood and the blood remaining in surgical gauzes. Additionally, the surgeon's satisfaction with the surgical field was evaluated by a scoring system. The collected data were, then, compared between the study groups by the statistical methods.

Results

Based on the current study findings, systolic (P < 0.001), diastolic (P = 0.002), and the mean arterial blood pressures (P < 0.001) were significantly lower in the nitroglycerine group. Ninety percent of the patients in the labetalol group received isoflurane to achieve the targeted blood pressure defined as controlled hypotension. There was no significant difference between the groups regarding the volume of bleeding (P = 0.75); however, the surgeons were more satisfied with nitroglycerine than labetalol (P < 0.001).

Conclusions

It was concluded that nitroglycerine had a better effect, in comparison to labetalol, on inducing the controlled hypotension in septorhinoplasty.

Post-traumatic acute kidney injury: a cross-sectional study of trauma patients

BACKGROUND

The causes of post-traumatic acute kidney injury (AKI) are multifactorial, and shock associated with major trauma has been proposed to result in inadequate renal perfusion and subsequent AKI in trauma patients. This study aimed to investigate the true incidence and clinical presentation of post-traumatic AKI in hospitalized adult patients and its association with shock at a Level I trauma center.

METHODS

Detailed data of 78 trauma patients with AKI and 14,504 patients without AKI between January 1, 2009 and December 31, 2014 were retrieved from the Trauma Registry System. Patients with direct renal trauma were excluded from this study. Two-sided Fisher's exact or Pearson's chi-square tests were used to compare categorical data, unpaired Student's t-test was used to analyze normally distributed continuous data, and Mann-Whitney's U test was used to compare non-normally distributed data. Propensity score matching with a 1:1 ratio with logistic regression was used to evaluate the effect of shock on AKI.

RESULTS

Patients with AKI presented with significantly older age, higher incidence rates of pre-existing comorbidities, higher odds of associated injures (subdural hematoma, intracerebral hematoma, intra-abdominal injury, and hepatic injury), and higher injury severity than patients without AKI. In addition, patients with AKI had a longer hospital stay (18.3 days vs. 9.8 days, respectively; P < 0.001) and intensive care unit (ICU) stay (18.8 days vs. 8.6 days, respectively; P < 0. 001), higher proportion of admission into the ICU (57.7% vs. 19.0%, respectively; P < 0.001), and a higher odds ratio (OR) of short-term mortality (OR 39.0; 95% confidence interval, 24.59-61.82; P < 0.001). However, logistic regression analysis of well-matched pairs after propensity score matching did not show a significant influence of shock on the occurrence of AKI.

DISCUSSION

We believe that early and aggressive resuscitation, to avoid prolonged untreated shock, may help to prevent the occurrence of post-traumatic AKI. However, more evidence is required to support this observation.

CONCLUSION

Compared to patients without AKI, patients with AKI presented with different injury characteristics and worse outcome. However, an association between shock and post-traumatic AKI could not be identified.

Neurogenic stunned myocardium in subarachnoid hemorrhage

"Stunned myocardium," characterized by reversible left ventricular dysfunction, was first described via animal models using transient coronary artery occlusion. However, this phenomenon has also been noted with neurologic pathologies and collectively been labeled "neurogenic stunned myocardium" (NSM). Neurogenic stunned myocardium resulting from subarachnoid hemorrhage (SAH) is a challenging pathology due to its diagnostic uncertainty. Traditional diagnostic criteria for NSM after SAH focus on electrocardiographic and echocardiographic abnormalities and troponemia. However, tremendous heterogeneity still exists. Traditional pathophysiological mechanisms for NSM encompassed hypothalamic and myocardial perivascular lesions. More recently, research on pathophysiology has centered on myocardial microvascular dysfunction and genetic polymorphisms. Catecholamine surging as a mechanism has also gained attention with particular focus placed on the role of adrenergic blockade in both the prehospital and acute settings. Management remains largely supportive with case reports acknowledging the utility of inotropes such as dobutamine and milrinone and intra-aortic balloon pump when NSM is accompanied by cardiogenic shock. Neurogenic stunned myocardium that follows SAH can result in many complications such as arrhythmias, pulmonary edema, and prolonged intubation, which can negatively impact long-term recovery from SAH and increase morbidity and mortality. This necessitates the need to accurately diagnose and treat NSM.

Medication error report: Intrathecal administration of labetalol during obstetric anesthesia

Labetalol, a combined alfa and beta-adrenergic receptor antagonist, is used as an antihypertensive drug. We report a case of an acute rise in blood pressure and lower limb pain due to the inadvertent intrathecal administration of labetalol, mistaking it for bupivacaine, during obstetric anesthesia. The situation was rescued by converting to general anesthesia. The cesarean delivery was uneventful, and mother as well as newborn child showed no ill-effect. This particular medication error was attributable to a failure on the part of the doctors administering the injection to read and cross-check medication labels and the practice of keeping multiple injections together. In the absence of an organized medication error reporting system and action on that basis, such events may recur in future.

Management of Acute Hypertensive Response in Patients With Ischemic Stroke

High blood pressure (BP) >140/90 mm Hg is seen in 75% of patients with acute ischemic stroke and in 80% of patients with acute intracerebral hemorrhages and is independently associated with poor functional outcome. While BP reduction in patients with chronic hypertension remains one of the most important factors in primary and secondary stroke prevention, the proper management strategy for acute hypertensive response within the first 72 hours of acute ischemic stroke has been a matter of debate. Recent guidelines recommend clinical trials to ascertain whether antihypertensive therapy in the acute phase of stroke is beneficial. This review summarizes the current data on acute hypertensive response or elevated BP management during the first 72 hours after an acute ischemic stroke. Based on the potential deleterious effect of lowering BP observed in some clinical trials in patients with acute ischemic stroke and because of the lack of convincing evidence to support acute BP lowering in those situations, aggressive BP reduction in patients presenting with acute ischemic stroke is currently not recommended. While the early use of angiotensin receptor antagonists may help reduce cardiovascular events, this benefit is not necessarily related to BP reduction.

Systolic blood pressure reduction and risk of acute renal injury in patients with intracerebral hemorrhage

BACKGROUND

Aggressive systolic blood pressure reduction may precipitate acute renal injury because of underlying hypertensive nephropathy in patients with intracerebral hemorrhage. The study's objective was to determine the rate and determinants of acute renal injury during acute hospitalization among subjects with intracerebral hemorrhage using a post hoc analysis of a multicenter prospective study.

METHODS

Subjects with intracerebral hemorrhage and elevated systolic blood pressure of 170 mm Hg or greater who presented within 6 hours of symptom onset and underwent treatment of acute hypertensive response and fluid management as per study and local protocols, respectively. Acute renal injury was defined post hoc using the criteria used in Acute Kidney Injury Network classifications within 72 hours of admission. Descriptive statistics and standard statistical tests were used to characterize and evaluate the effect of systolic blood pressure reduction parameters (relative to initial systolic blood pressure) and average maximum hourly dose of nicardipine on the occurrence of acute renal injury.

RESULTS

A total of 60 subjects were recruited (57% were men; mean age of 62.0 ± 15.1 years). Five subjects (9%) had stage I acute renal injury according to the Acute Kidney Injury Network criteria. None of the subjects had stage II or III acute renal injury. The serum creatinine course for the first 3 days suggested that the peak elevation of creatinine was seen at 18, 30, 57, 58, and 71 hours after baseline measurements in these 5 subjects, all of which except for the first one were beyond the protocol-specified treatment period. The incidences of neurologic deterioration and symptomatic hematoma expansion were significantly greater in the subjects with stage I renal impairment. The systolic blood pressure reduction parameters (in particular, the area under the curve depicting the 24-hour systolic blood pressure summary statistic) and the higher average maximum hourly nicardipine dose were strongly associated with stage I renal impairment.

CONCLUSIONS

Although acute renal injury is infrequent and mild among subjects with intracerebral hemorrhage undergoing systolic blood pressure reduction, a trend in association between systolic blood pressure reduction and renal impairment was observed in this small study. Therefore, it is important to carefully monitor the renal function when administering treatment to reduce systolic blood pressure in patients with intracerebral hemorrhage.

Preadmission beta-blockers are associated with decreased incidence of neurogenic stunned myocardium in aneurysmal subarachnoid hemorrhage

BACKGROUND

Neurogenic stunned myocardium (NSM) is a frequent complication of aneurysmal subarachnoid hemorrhage (aSAH), with a significant impact on disease course. The presumed cause is catecholamine surge at the time of aneurysm rupture. Beta-blockers, which reduce the impact of the catecholamine surge, may decrease the risk of developing NSM.

METHODS

A chart review of 234 consecutive patients admitted to the Oregon Health and Science University Neurosurgery service between March 6, 2008 and June 23, 2010 with a diagnosis of aneurysmal SAH was performed. This group was further subdivided by patients who received echocardiograms on admission, by gender, and by the prehospital administration of β-blockers.

RESULTS

One hundred thirty of 234 patients had echocardiograms on or shortly after admission, and 18 of these developed NSM (13.8%). None of the 22 patients taking prehospital β-blockers developed NSM. Using the Fisher exact test to compare the 2 groups, patients who were administered prehospital β-blockers were significantly less likely to develop stunning compared to those who were not (P = .04). After correcting for other variables using multiple logistic regression analysis, the previous use of β-blockers was still found to be significantly associated with a decreased incidence of NSM after SAH (P = .049). There was no significant difference in hospital length of stay, peribleed stroke, vasospasm, or death. Of the 18 patients with stunning, 15 were women, 5 of whom were on estrogen supplementation. The mean peak troponin elevation of women who developed NSM on estrogen supplementation was significantly higher than for those who were not (mean peak troponin 9.97 ± 2.01 mg/dL; P < .001).

CONCLUSION

Prehospital β-blockers are associated with decreased risk of developing NSM in patients with aSAH. Estrogen may play an additional role in shaping the degree of NSM in women.

Safety and efficacy of intravenous labetalol for hypertensive crisis in infants and small children

OBJECTIVE

To determine the efficacy and safety of labetalol for hypertensive crisis in children ≤ 24 months of age.

DESIGN

Retrospective chart review. Statistical analysis utilized analysis of variance for continuous data, chi-square tests for nominal data, and linear regression.

SETTING

A 737-bed pediatric teaching institution.

PATIENTS

Twenty-seven patients ≤ 24 months of age were treated with 37 intravenous infusions of labetalol, nicardipine, or nitroprusside for hypertensive crisis or hypertensive urgency.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary end point consisted of time to 20% reduction in systolic blood pressure. Primary safety end points measured the prevalence of deleterious effects of labetalol. Continuous infusion of labetalol reduced mean systolic blood pressure by at least 20% in < 8 hrs. This effect was similar to nicardipine and nitroprusside infusions. The reported side effects were similar in each group. Patients receiving labetalol and presenting with ischemic or traumatic brain injury were likely to develop hypotension requiring infusion discontinuation.

CONCLUSIONS

Continuous intravenous labetalol infusion is efficacious for treatment of hypertensive crisis in children ≤ 24 months of age. Aside from patients presenting with ischemic or traumatic brain injury, labetalol was safe to use in this population for hypertensive emergencies and had a satisfactory adverse effect profile. Labetalol may reach dose saturation at a much lower dose in young children in comparison to adults. Clinicians should use caution when initiating labetalol infusions in young patients with brain injury.

Labetalol infusion for refractory hypertension causing severe hypotension and bradycardia: an issue of patient safety

Incremental doses of intravenous labetalol are safe and effective and, at times, such therapy may need to be augmented by a continuous infusion of labetalol to control severe hypertension. Continuous infusions of labetalol may exceed the recommended maximum daily dose of 300 mg on occasion. We report a case in which hypertension occurring after an abdominal aortic aneurysm repair, initially responsive to intermittent intravenous beta-blockade, became resistant to this therapy leading to the choice of an intravenous labetalol infusion as the therapeutic option. The labetalol infusion resulted in a profound cardiovascular compromise in this postoperative critically ill patient. While infusions of labetalol have successfully been used, prolonged administration in the intensive care unit requires vigilance and the establishment of a therapeutic rationale/policy for interventions, such as the ready availability of glucagon, beta-agonists, phosphodiesterase inhibitors, insulin, and vasopressin when severe cardiovascular depression occurs.

Fatal intoxication with labetalol (Trandate)

The dead body of a 44-year-old woman, previously known for depression and alcoholism, has been discovered at her place of residence by her husband. A forensic autopsy has been carried out. The results indicated unspecific histological lesions (alveolar oedema, liver steatosis and interstitial nephritis) but did not reveal any apparent cause of death. Several boxes of medicines have been found near the body, justifying a toxicological analysis. This has been performed on peripheral blood and urine samples using liquid chromatography with diode array and mass spectrometric detections, in conjunction with gas chromatography coupled with mass spectrometry. Ethanol has been found (1.24 g/L in blood, 2.63 g/L in urine and 1.33 g/kg in gastric content), as well as therapeutic concentrations of meprobamate (14.1mg/L) and low concentrations of nordazepam (0.12 mg/L) in blood. On the other hand, particularly high levels of labetalol, a widely used beta-blocker, have been found both in blood (1.7 mg/L) and urine (20.2mg/L), which led us to measure labetalol levels in available viscera samples (liver, heart, kidney, and lung) and gastric content. Measured concentrations were 14.2 microg/g, 7.8 microg/g, 5.4 microg/g, 5.2 microg/g and 31.1 microg/g, respectively. We describe here the first report of a fatal intoxication attributed to labetalol that is linked to its acute toxicity, with tissue distribution of this beta-blocker.