Depressive Symptoms and Risk of Postoperative Delirium.

OBJECTIVE: Previous studies have shown that elevated depressive symptoms are associated with increased risk of postoperative delirium. However, to our knowledge no previous studies have examined whether different components of depression are differentially predictive of postoperative delirium. METHODS: One thousand twenty patients were screened for postoperative delirium using the Confusion Assessment Method and through retrospective chart review. Patients underwent cognitive, psychosocial, and medical assessments preoperatively. Depression was assessed using the Geriatric Depression Scale-Short Form. RESULTS: Thirty-eight patients developed delirium (3.7%). Using a factor structure previously validated among geriatric medical patients, the authors examined three components of depression as predictors of postoperative delirium: negative affect, cognitive distress, and behavioral inactivity. In multivariate analyses controlling for age, education, comorbidities, and cognitive function, the authors found that greater behavioral inactivity was associated with increased risk of delirium (OR: 1.95 [1.11, 3.42]), whereas negative affect (OR: 0.65 [0.31, 1.36]) and cognitive distress (OR: 0.95 [0.63, 1.43]) were not. CONCLUSION: Different components of depression are differentially predictive of postoperative delirium among adults undergoing noncardiac surgery.

Does depth of anesthesia monitoring improve postoperative outcomes?

PURPOSE OF REVIEW: Devices using the electroencephalogram to estimate anesthetic depth have been available since 1996. Despite the use of these monitors for over a decade, there is little agreement among clinicians about the need for or value of depth of anesthesia monitoring. Since the majority of the studies evaluating the impact of depth of anesthesia monitoring on postoperative outcomes have utilized the bispectral index (BIS Covidian), this manuscript will focus on studies with this device. This review will evaluate the evidence that BIS monitoring can improve long-term outcomes. RECENT FINDINGS: BIS-guided anesthesia can reduce the incidence of awareness with recall in high-risk patients, but a recent study found that anesthetic management directed by an end-tidal anesthetic-agent concentration protocol is equally effective, and probably less expensive. Deep anesthesia (BIS < 45) during the intraoperative period is associated with increased postoperative mortality, but this relationship may be an epiphenomenon rather than causal. SUMMARY: There is growing concern that anesthetic management and even specific anesthetic agents may worsen outcomes in high-risk patients. There is, however, no conclusive evidence that depth of anesthesia monitors can improve outcomes and no evidenced-based reasons for anesthesia providers to change their current practice.

Dexmedetomidine and magnesium sulfate in the perioperative management of a child undergoing laparoscopic resection of bilateral pheochromocytomas.

The case of an 8 year-old boy undergoing resection of pheochromocytoma, who received a combination of dexmedetomidine and magnesium sulfate (MgSO4) for hemodynamic control, is reported. He was prepared for surgery with phenoxybenzamine and atenolol. Dexmedetomidine was started in the preoperative holding area and, with MgSO4, continuously infused for most of the case. Good cardiovascular stability was achieved, but low-dose esmolol and nicardipine infusions were required during tumor manipulation. There was minimal post-resection hypotension, the neuromuscular block was easily antagonized, and the child's trachea was quickly extubated.

Executive function and depression as independent risk factors for postoperative delirium.

BACKGROUND: Postoperative delirium has been associated with greater complications, medical cost, and increased mortality during hospitalization. Recent evidence suggests that preoperative executive dysfunction and depression may predict postoperative delirium; however, the combined effect of these risk factors remains unknown. This study examined the association among preoperative executive function, depressive symptoms, and established clinical predictors of postoperative delirium among 998 consecutive patients undergoing major noncardiac surgery. METHODS: A total of 998 patients were screened for postoperative delirium (n = 998) using the Confusion Assessment Method as well as through retrospective chart review. Patients underwent cognitive, psychosocial, and medical assessments preoperatively. Executive function was assessed using the Concept Shifting Task, Letter-Digit Coding, and a modified Stroop Color Word Interference Test. Depression was assessed by the Beck Depression Inventory. RESULTS: Preoperative executive dysfunction (P = 0.007) and greater levels of depressive symptoms (P = 0.049) were associated with a greater incidence of postoperative delirium, independent of other risk factors. Secondary analyses of cognitive performance demonstrated that the Stroop Color Word Interference Test, the executive task with the greatest complexity in this battery, was more strongly associated with postoperative delirium than simpler tests of executive function. Furthermore, patients exhibiting both executive dysfunction and clinically significant levels of depression were at greatest risk for developing delirium postoperatively. CONCLUSIONS: Preoperative executive dysfunction and depressive symptoms are predictive of postoperative delirium among noncardiac surgical patients. Executive tasks with greater complexity are more strongly associated with postoperative delirium relative to tests of basic sequencing.

Measures of executive function and depression identify patients at risk for postoperative delirium.

BACKGROUND: Postoperative delirium is associated with increased morbidity and mortality. Preexisting cognitive impairment and depression have been frequently cited as important risk factors for this complication. This prospective cohort study was designed to determine whether individuals who perform poorly on preoperative cognitive tests and/or exhibited depressive symptoms would be at high risk for the development of postoperative delirium. METHODS: One hundred nondemented patients, aged 50 yr and older, scheduled to undergo major, elective noncardiac surgery completed a preoperative test battery that included measures of global cognition, executive function, and symptoms of depression. Known preoperative risk factors for delirium were collected and examined with the results of the preoperative test battery to determine the independent predictors of delirium. RESULTS: The overall incidence of delirium was 16% and was associated with increased hospital duration of stay (P < 0.05) and an increased incidence of postoperative complications (P < 0.01). Delirious subjects did not differ from their nondelirious cohorts with regard to their preoperative global cognitive function, preexisting medical comorbidities, age, anesthetic management, or history of alcohol use. Preoperative executive scores (P < 0.001) and depression (P < 0.001), as measured by the Trail Making B test and Geriatric Depression Scale-Short Form, respectively, were found to be independent predictors of postoperative delirium. CONCLUSIONS: Low preoperative executive scores and depressive symptoms independently predict postoperative delirium in older individuals. A rapid, simple test combination including tests of executive function and depression could improve physicians' ability to recognize patients who might benefit from a perioperative intervention strategy to prevent postoperative delirium.

Predictors of cognitive dysfunction after major noncardiac surgery.

BACKGROUND: The authors designed a prospective longitudinal study to investigate the hypothesis that advancing age is a risk factor for postoperative cognitive dysfunction (POCD) after major noncardiac surgery and the impact of POCD on mortality in the first year after surgery. METHODS: One thousand sixty-four patients aged 18 yr or older completed neuropsychological tests before surgery, at hospital discharge, and 3 months after surgery. Patients were categorized as young (18-39 yr), middle-aged (40-59 yr), or elderly (60 yr or older). At 1 yr after surgery, patients were contacted to determine their survival status. RESULTS: At hospital discharge, POCD was present in 117 (36.6%) young, 112 (30.4%) middle-aged, and 138 (41.4%) elderly patients. There was a significant difference between all age groups and the age-matched control subjects (P < 0.001). At 3 months after surgery, POCD was present in 16 (5.7%) young, 19 (5.6%) middle-aged, and 39 (12.7%) elderly patients. At this time point, the prevalence of cognitive dysfunction was similar between age-matched controls and young and middle-aged patients but significantly higher in elderly patients compared to elderly control subjects (P < 0.001). The independent risk factors for POCD at 3 months after surgery were increasing age, lower educational level, a history of previous cerebral vascular accident with no residual impairment, and POCD at hospital discharge. Patients with POCD at hospital discharge were more likely to die in the first 3 months after surgery (P = 0.02). Likewise, patients who had POCD at both hospital discharge and 3 months after surgery were more likely to die in the first year after surgery (P = 0.02). CONCLUSIONS: Cognitive dysfunction is common in adult patients of all ages at hospital discharge after major noncardiac surgery, but only the elderly (aged 60 yr or older) are at significant risk for long-term cognitive problems. Patients with POCD are at an increased risk of death in the first year after surgery.

Blood conservation in pediatric anesthesia.

This review focuses on perioperative blood conservation techniques and the role of transfusion triggers and algorithms, preoperative autologous donation, acute normovolemic hemodilution, intraoperative blood salvage, deliberate hypotension, and preoperative recombinant human erythropoietin in avoiding allogeneic blood transfusion in pediatric patients.

Intratracheal pressure: a more accurate reflection of pulmonary airway pressure in pediatric patients with respiratory failure.

OBJECTIVES: Peak inflation pressure (PIP) on many ventilators (P(vent)), measured distal to the exhalation limb or Y-piece of the breathing circuit, is assumed as the pressure applied to the airways and lungs. However, in vitro studies show P(vent) data are spurious. There are no studies evaluating the accuracy of P(vent) data for pediatric patients with acute respiratory failure. We hypothesized that intratracheal airway pressure (P(T)) is more accurate than P(vent) and that by using P(vent), abnormally increased imposed resistive work of breathing (WOBi) may go undetected. DESIGN: Prospective and descriptive study. SETTING: A pediatric intensive care unit at a university hospital. PATIENTS: Twenty-one pediatric patients with respiratory failure requiring mechanical ventilation. INTERVENTIONS: All patients were intubated with a commercially available endotracheal tube (ETT) with a pressure measuring the lumen opening at the distal end used for measuring P(T). Pressure/flow sensors positioned between the ETT and Y-piece measured tidal volume (V(T)) and flow rate. P(vent) data were recorded as displayed on the ventilator. WOBi was measured by integrating P(T) and V(T) data. RESULTS: PIP at P(vent) and P(T) were 26 +/- 8 cm H(2)O and 19 +/- 7 cm H(2)O, respectively (p < .05). P(T) measurements averaged 27% less than P(vent). The relationship between P(vent)-P(T) (pressure drop across the breathing circuit and ETT) and flow rate during spontaneous inhalation was highly correlated (r = .80, p < .002), indicating the greater the flow rate, the greater the pressure drop and WOBi. WOBi, ranging from 0.04-1.5 J/L, was measured in 52% of the patients. CONCLUSIONS: P(vent) significantly overestimates PIP. Moreover, P(vent) data does not allow for recognition of increased WOBi for many patients. Clinicians need to be aware of the limitations of P(vent) data and consider using ETTs that allow measurement of P(T), a more accurate reflection of pulmonary airway pressure.

Anesthetic management and one-year mortality after noncardiac surgery.

Little is known about the effect of anesthetic management on long-term outcomes. We designed a prospective observational study of adult patients undergoing major noncardiac surgery with general anesthesia to determine if mortality in the first year after surgery is associated with demographic, preoperative clinical, surgical, or intraoperative variables. One-year mortality was 5.5% in all patients (n = 1064) and 10.3% in patients > or =65 yr old (n=243). Multivariate Cox Proportional Hazards modeling identified three variables as significant independent predictors of mortality: patient comorbidity (relative risk, 16.116; P <0.0001), cumulative deep hypnotic time (Bispectral Index <45) (relative risk=1.244/h; P=0.0121) and intraoperative systolic hypotension (relative risk=1.036/min; P=0.0125). Death during the first year after surgery is primarily associated with the natural history of preexisting conditions. However, cumulative deep hypnotic time and intraoperative hypotension were also significant, independent predictors of increased mortality. These associations suggest that intraoperative anesthetic management may affect outcomes over longer time periods than previously appreciated.

The effect of caudal analgesia on emergence agitation in children after sevoflurane versus halothane anesthesia.

UNLABELLED: Sevoflurane anesthesia in young children has been associated with an increased incidence of emergence agitation compared with halothane. Postoperative pain may be an etiologic factor. We designed a study to compare the incidence of emergence agitation after halothane and sevoflurane anesthesia in children whose pain was managed with caudal analgesia. Eighty children undergoing inguinal hernia repair between the ages of 12 mo and 6 yr were randomly assigned to receive either halothane or sevoflurane anesthesia. Baseline preoperative anxiety was assessed with the Yale Preoperative Anxiety Scale. The children were sedated with oral midazolam, underwent a mask induction, and had a caudal block placed for postoperative analgesia. After surgery, the children's behavior was assessed with a four-point agitation scale. At 5 min after arrival in the postanesthesia care unit (PACU), sevoflurane was associated with a greater incidence of emergence agitation than halothane (26% vs 6%; P < 0.05), but not during the remainder of the PACU stay. Higher levels of preoperative anxiety were associated with difficult mask induction, agitation on admission to the PACU, and more severe agitation episodes. Emergence agitation appears to be an early and transient phenomenon after sevoflurane anesthesia in children with effective postoperative analgesia. IMPLICATIONS: Effective postoperative analgesia may reduce the incidence of emergence agitation reported with sevoflurane anesthesia. The Yale Preoperative Anxiety Scale appears to be helpful in identifying young children who are at risk for developing emergence agitation.

A comparison of three doses of a commercially prepared oral midazolam syrup in children.

UNLABELLED: Midazolam is widely used as a preanesthetic medication for children. Prior studies have used extemporaneous formulations to disguise the bitter taste of IV midazolam and to improve patient acceptance, but with unknown bioavailability. In this prospective, randomized, double-blinded study we examined the efficacy, safety, and taste acceptability of three doses (0.25, 0.5, and 1.0 mg/kg, up to a maximum of 20 mg) of commercially prepared Versed((R)) syrup (midazolam HCl) in children stratified by age (6 mo to <2 yr, 2 to <6 yr, and 6 to <16 yr). All children were ASA class I-III scheduled for elective surgery. Subjects were continuously observed and monitored with pulse oximetry. Ninety-five percent of patients accepted the syrup, and 97% demonstrated satisfactory sedation before induction. There was an apparent relationship between dose and onset of sedation and anxiolysis (P < 0.01). Eight-eight percent had satisfactory anxiety ratings at the time of attempted separation from parents, and 86% had satisfactory anxiety ratings at face mask application. The youngest age group recovered earlier than the two older age groups (P < 0.001). There was no relationship between midazolam dose and duration of postanesthesia care unit stay. Before induction, there were no episodes of desaturation, but there were two episodes of nausea and three episodes of emesis. At the time of induction, during anesthesia, and in the postanesthesia care unit, there were several adverse respiratory events. Oral midazolam syrup is effective for producing sedation and anxiolysis at a dose of 0.25 mg/kg, with minimal effects on respiration and oxygen saturation even when administered at doses as large as 1.0 mg/kg (maximum, 20 mg) as the sole sedating medication to healthy children in a supervised clinical setting. IMPLICATIONS: Commercially prepared oral midazolam syrup is effective in producing sedation and anxiolysis in doses as small as 0.25 mg/kg; there is a slightly faster onset with increasing the dose to 1.0 mg/kg. At all doses, 97% of patients demonstrated satisfactory sedation, whereas 86% demonstrated satisfactory anxiolysis when the face mask was applied.