Anupa Deogaonkar

Bispectral Index monitoring correlates with sedation scales in brain-injured patients

Objective:Monitoring critically ill, brain-injured patients with a decreased level of consciousness is challenging. Our goal is to determine in this population the correlation between the Bispectral Index (BIS) and three commonly used sedation agitation scales: the Richmond Agitation-Sedation Scale (RASS), the Sedation-Agitation Scale (SAS) and the Glasgow Coma Scale (GCS) scores. Design:Prospective, single-blinded observational study. Setting:Eight-bed neurology-neurosurgery intensive care unit at the Cleveland Clinic Foundation. Patients:Thirty critically ill patients admitted to the neurointensive care unit with primary brain injury and a decreased level of consciousness. Measurements and Main Results:Patients were prospectively evaluated for level of consciousness using the RASS, SAS, and GCS every hour and simultaneously were monitored continuously with a BIS monitor for 6 hrs. A Spearman’s correlation coefficient was used to correlate the BIS scores with clinical scales. In 15 patients monitored with the newer BIS XP version, the BIS values correlated significantly with the RASS (R2 = .810; p < .0001), SAS (R2 = .725; p < .0001), and GCS (R2 = .655; p < .0001). In 15 patients monitored with the older BIS 2.1.1 software, the correlation was as follows: for RASS, R2 = .30 (p < .008), for SAS: R2 = .376 (p < .001), and for GCS: R2 = .274 (p < .015). This correlation was maintained in patients who received sedative medications. Conclusions:A statistically significant correlation existed between BIS values and the RASS, SAS, and GCS scores in critically ill brain-injured patients, with and without sedation. The newer BIS XP software package may be a useful adjunctive tool in objective assessment of level of consciousness in brain-injured patients.

Multimodal monitoring in the neurological intensive care unit

Background:Neurocritical care is a specialty that focuses on the critical care management of patients with catastrophic neurologic diseases. Brain ischemia and hypoxia are often central causes of brain damage in these patients. Until recently, the only methods widely accepted for monitoring in the neurological intensive care unit have been intracranial pressure and cerebral perfusion pressure monitoring. Recent developments in technology have resulted in several new monitoring techniques that can provide the neurointensivist with information, at the cellular level, that can help guide management. Review Summary:The brain requires a continuous blood-borne supply of oxygen and glucose for normal metabolism. Ischemia occurs when supply is insufficient to meet the metabolic demand. Cerebral blood flow can now be directly monitored using laser Doppler or thermal diffusion techniques. Transcranial cerebral oximetry can estimate regional cerebral oxygen saturation, although the reliability is questionable. Jugular bulb oximetry can provide a global assessment of oxygen delivery, and consumption and brain tissue oxygen tension monitoring can provide a focal measurement of cerebral oxygenation. Intracerebral microdialysis can provide information about glucose metabolism and the overall health of the neuron. Conclusions:New monitoring techniques can provide the neurointensivist with crucial information about brain physiology and metabolism. Combining these techniques (“multimodal monitoring”) can produce a more accurate overall picture. This approach, along with new computer systems for integrating data at the bedside, may change the way patients with brain injury are monitored and treated in the future.

Venous Air Embolism during Deep Brain Stimulation Surgery in an Awake Supine Patient

Deep brain stimulation (DBS) of the subthalamic nucleus and globus pallidus is used to improve Parkinsonian symptoms and reduce levodopa-induced motor complications in Parkinson’s disease (PD). This procedure is usually performed with minimal or no sedation to allow accurate feedback from patients during surgery. Venous air embolism (VAE) has been previously reported in patients undergoing awake neurosurgical procedures for brain tumors or pallidotomy for PD. We describe a case of intraoperative VAE in an awake, supine patient while undergoing DBS surgery for PD who presented with coughing, tachypnea and hypoxemia. The difference in clinical presentation between VAE in awake vs. anesthetized patients is discussed as are intraoperative monitoring techniques and management options.

Precordial Doppler Probe Placement for Optimal Detection of Venous Air Embolism During Craniotomy

Verification of appropriate precordial Doppler probe position over the anterior chest wall is crucial for early detection of venous air embolism. We studied responses to normal saline (NS) and carbon dioxide (CO2) test injections at various probe locations during elective craniotomy. All patients received four IV injections (10 mL of NS and 1 mL of CO2 via central and peripheral venous catheters). Doppler sounds were simultaneously recorded with two separate probes. In Group A, probes were placed in left and right parasternal positions. In Group B, the left probe was intentionally malpositioned as far laterally over the left precordium as was compatible with an audible signal. In Group A (n = 23), a left parasternal Doppler signal was easily obtainable in 23 of 23 patients, versus 18 of 23 patients for the right parasternal probe (P < 0.05). In Group B (n = 17), central CO2 injection yielded a positive right parasternal response rate of 88% compared with 29% over the far left precordium (P < 0.015), where central NS injections yielded a 76% response rate (P < 0.015 versus central CO2 injection). Left parasternal placement is at least as sensitive to clinical venous air embolism events as right parasternal placement. Peripheral saline injection represents a viable alternative (83% response rate). Vigorous central injection of 10 mL of NS however, risks false positive verification of left lateral precordial probe placement.

Propofol-induced dyskinesias controlled with dexmedetomidine during deep brain stimulation surgery.

for the next 5 min. At this point, 1.5 g/kg dexmedetomidine was administered as a loading dose over 20 min. The patient’s dyskinesias subsided within 18 –20 min of dexmedetomidine infusion. The dexmedetomidine infusion rate was then reduced to 1.2 g kg 1 h 1 for another 10 min, after which it was continued at a rate of 0.2– 0.5 g kg 1 h 1 . When the infusion was stopped just before the microelectrode recordings, dyskinesias recurred. The dexmedetomidine infusion was restarted with good control of dyskinetic movements and titrated to keep the patient sufficiently awake to answer questions. Specifically, during microstimulation at the end of microelectrode recording for each tract, the patient was asked whether he experienced paresthesias or pulling in the muscles of his face, arms, or legs. During macrostimulation at the time of placement of the DBS electrodes, he was asked to move his fingers or toes. This allowed satisfactory placement of bilateral subthalamic nucleus DBS electrodes. Approximately an hour after surgery, the patient had another brief episode of dyskinesias that subsided spontaneously while he was in the postoperative care unit. The patient was off dexmedetomidine infusion at this time. The patient did well postoperatively and was discharged home without further problems. During his follow-up visit at 5 weeks, he reported improvement of all symptoms, indicating satisfactory DBS function.

Pre-existing do-not-resuscitate orders are not associated with increased postoperative morbidity at 30 days in surgical patients

Objective:To assess the relationship between pre-existing do-not-resuscitate orders and the incidence of postoperative 30-day minor morbidity in surgical patients. Design:Retrospective analysis of prospectively collected data from the American College of Surgeons National Surgical Quality Improvement Program database in patients undergoing general surgical procedures between 2005 and 2008. Setting:All U.S. hospitals that participated in the American College of Surgeons National Surgical Quality Improvement Program, which is the nationally validated, risk-adjusted, outcomes-based program that uses a prospective, peer-controlled, validated database to quantify 30-day risk-adjusted surgical outcomes, allowing valid comparison of outcomes among all hospitals in the program. Interventions:American College of Surgeons National Surgical Quality Improvement Program data included preoperative risk factors, intraoperative variables, and 30-day postoperative mortality and morbidity outcomes for patients undergoing major surgical procedures in both the inpatient and outpatient setting. The data were collected, validated, and submitted by a trained Surgical Clinical Reviewer at each site. Association between do-not-resuscitate status and minor and major morbidities was assessed using proportional hazards models adjusting for death as a competing risk. Measurements and Main Results:Of 635,265 patients in the database, 576,745 patients were analyzed. Propensity-matched analysis successfully matched 2,199 (of 2,687 [81.8%]) patients having pre-existing do-not-resuscitate orders (DNR group) with 6,002 non-do-not-resuscitate control subjects (nonDNR group). At any time point within 30 days of surgery, DNR patients were 16% (95% confidence interval, 3–28%; p = .02) less likely to have a minor complication as compared with nonDNR patients after accounting for the competing risk of death. DNR patients were more likely to experience 30-day mortality compared with nonDNR patients (hazard ratio, 2.3; 95% confidence interval, 1.9–2.7; p < .001). However, there was no association between pre-existing do-not-resuscitate orders and occurrence of any major complication (p = .65) treating death as a competing risk event. When associations between do-not-resuscitate orders and individual minor complications were analyzed, a pre-existing do-not-resuscitate order remained independently associated only with decreased odds of superficial surgical site infection (p = .001). Conclusions:Undergoing surgery with a pre-existing do-not-resuscitate order did not increase the risk of having a postoperative minor or major morbidity at any time within the 30-day postoperative period. Results of health care in U.S. hospitals do not differ based on presence of do-not-resuscitate orders.

Intraoperative Tight Glucose Control Using Hyperinsulinemic Normoglycemia Increases Delirium after Cardiac Surgery

Background:Postoperative delirium is common in patients recovering from cardiac surgery. Tight glucose control has been shown to reduce mortality and morbidity. Therefore, the authors sought to determine the effect of tight intraoperative glucose control using a hyperinsulinemic–normoglycemic clamp approach on postoperative delirium in patients undergoing cardiac surgery. Methods:The authors enrolled 198 adult patients having cardiac surgery in this randomized, double-blind, single-center trial. Patients were randomly assigned to either tight intraoperative glucose control with a hyperinsulinemic–normoglycemic clamp (target blood glucose, 80 to 110 mg/dl) or standard therapy (conventional insulin administration with blood glucose target, <150 mg/dl). Delirium was assessed using a comprehensive delirium battery. The authors considered patients to have experienced postoperative delirium when Confusion Assessment Method testing was positive at any assessment. A positive Confusion Assessment Method was defined by the presence of features 1 (acute onset and fluctuating course) and 2 (inattention) and either 3 (disorganized thinking) or 4 (altered consciousness). Results:Patients randomized to tight glucose control were more likely to be diagnosed as being delirious than those assigned to routine glucose control (26 of 93 vs. 15 of 105; relative risk, 1.89; 95% CI, 1.06 to 3.37; P = 0.03), after adjusting for preoperative usage of calcium channel blocker and American Society of Anesthesiologist physical status. Delirium severity, among patients with delirium, was comparable with each glucose management strategy. Conclusion:Intraoperative hyperinsulinemic–normoglycemia augments the risk of delirium after cardiac surgery, but not its severity.

Perioperative complications of blood brain barrier disruption under general anesthesia: A retrospective review

Blood brain barrier disruption enhances drug delivery in primary central nervous system lymphoma. In this study, we report adverse events that were encountered intraoperatively and in the postoperative period in these patients. A retrospective analysis of 17 patients documenting demographic data, preprocedure medical history, intraoperative, and postoperative anesthetic complications was conducted between January 2002 and December 2004. Seventeen patients underwent 210 treatments under general anesthesia with a mean of 12.4±7.2 treatments per patient. Focal seizures occurred in 13% of patients. Generalized motor seizures occurred in 4 treatment sessions in 2 different patients. The incidence of seizures was significantly higher when the internal carotid artery was used for injection, as opposed to the vertebral artery (20.8% and 6.02%, respectively, P=0.0034). Tachycardia associated with ST segment depression occurred 9 times (4.3%) in 3 patients. One patient had significant ST segment elevation (more than 1.5 mm). Transient cerebral vasospasm after methotrexate injection occurred in 9% of patients. Postoperative nausea and vomiting were observed in 11.9% of patients. After emergence, lethargy and obtundation occurred in 7.6% of the cases. The incidence of postoperative headache and reversible motor deficits was 6% and 3.8%, respectively. Our review highlights the problems that were encountered during blood brain barrier disruption under anesthesia and in the postoperative period. Further prospective studies are required for comprehensive evaluation of intraprocedure and postprocedure complications that will allow development of an optimal anesthetic plan and will improve patient outcome by preventing potential complications.

The clinical quandary of counseling the moribund critical care patient—a registry analysis of postsurgical outcomes ☆

PURPOSE To provide outcomes data to intensivists and surgeons for counseling patients and family members when considering a surgical intervention in a moribund patient. MATERIALS AND METHODS Retrospective analysis of prospectively collected data from the American College of Surgeons National Surgical Quality Improvement Program database in moribund patients undergoing general surgical procedures. RESULTS Out of 633,262 patients available in the national registry, 2063 (0.3%) were of moribund status. Post-operative mortality was 52.8% for moribund patients. Those who died had higher rates of compromised respiratory, renal and cognitive dysfunction, were older, less independent prior to surgery and had generally longer surgeries. 83% of patients experienced a major complication including mortality and 17 % of patients experienced minor complications. CONCLUSION The moribund patient is not as grave as once thought and surgery on these patients may not be futile given the 47% survival rate at 30 days. Postoperative complication rates are high. The data presented provide a meaningful tool for the clinicians in counseling patients and families on the expectations when considering a surgical intervention for moribund patients.

A Propensity-Matched Comparison of the Incidence of New-Onset Postoperative Atrial Arrhythmias in Cardiac and Noncardiac Thoracic Surgery Patients

OBJECTIVE The primary aim of this investigation was to compare the incidence of new-onset postoperative atrial arrhythmias (POAAs) in cardiac versus noncardiac thoracic surgery patients. A subgroup analysis also was performed in the cardiac surgery patients comparing POAAs in patients who underwent cardiac surgery on and off cardiopulmonary bypass (CPB). DESIGN This was a retrospective study using the Department of Cardiothoracic Anesthesia patient registry. All patients (n = 33,500) undergoing cardiac (n = 29,057) and noncardiac thoracic (n = 4,443) surgeries between 1993 and 2004 were identified from the patient registry. Two propensity-matched comparisons for the incidence of POAAs were made: (1) in cardiac surgery patients versus noncardiac thoracic surgery patients and (2) in patients undergoing cardiac surgery with versus without CPB. SETTING A large metropolitan multidisciplinary clinic. PARTICIPANTS Patients. INTERVENTION No interventions were done because this was a retrospective study. MEASUREMENTS AND MAIN RESULTS The cardiac patients had a significantly higher incidence of POAAs when compared with noncardiac thoracic surgery patients (11.6% v 7.5%, p < 0.001). There was no significant difference in the incidence of POAAs between patients undergoing CPB versus off-pump CPB (13.3% v 12.3%, p = 0.3). CONCLUSION The incidence of new-onset POAAs was higher in patients undergoing cardiac surgery than in patients undergoing noncardiac thoracic surgery in propensity-matched patient groups. CPB was not associated with new-onset POAAs.