Sabera Hossain

Predictors of hypotension after induction of general anesthesia.

Hypotension after induction of general anesthesia is a common event. In the current investigation, we sought to identify the predictors of clinically significant hypotension after the induction of general anesthesia. Computerized anesthesia records of 4096 patients undergoing general anesthesia were queried for arterial blood pressure (BP), demographic information, preoperative drug history, and anesthetic induction regimen. The median BP was determined preinduction and for 0–5 and 5–10 min postinduction of anesthesia. Hypotension was defined as either: mean arterial blood pressure (MAP) decrease of >40% and MAP <70 mm Hg or MAP <60 mm Hg. Overall, 9% of patients experienced severe hypotension 0–10 min postinduction of general anesthesia. Hypotension was more prevalent in the second half of the 0–10 min interval after anesthetic induction (P < 0.001). In 2406 patients with retrievable outcome data, prolonged postoperative stay and/or death was more common in patients with versus those without postinduction hypotension (13.3% and 8.6%, respectively, multivariate P < 0.02). Statistically significant multivariate predictors of hypotension 0–10 min after anesthetic induction included: ASA III–V, baseline MAP <70 mm Hg, age ≥50 yr, the use of propofol for induction of anesthesia, and increasing induction dosage of fentanyl. Smaller doses of propofol, etomidate, and thiopental were not associated with less hypotension. To avoid severe hypotension, alternatives to propofol anesthetic induction (e.g., etomidate) should be considered in patients older than 50 yr of age with ASA physical status ≥3. We conclude that it is advisable to avoid propofol induction in patients who present with baseline MAP <70 mm Hg.

The Visual Analog Scale for Pain: Clinical Significance in Postoperative Patients

Background The visual analog scale is widely used in research studies, but its connection with clinical experience outside the research setting and the best way to administer the VAS forms are not well established. This study defines changes in dosing of intravenous patient-controlled analgesia as a clinically relevant outcome and compares it with VAS measures of postoperative pain. Methods Visual analog scale measurements were obtained from 150 patients on the morning after intraabdominal surgery. On the same afternoon, 50 of the patients provided a VAS score on the same form used in the morning, 50 on a new form, and 50 were not asked for a second VAS measurement. Results Visual analog scale values and changes in value were similar for patients who were given a new VAS form in the afternoon and those who used the form that showed the morning value. The proportions of patients requesting additional analgesia were 4, 43, and 80%, corresponding to afternoon VAS scores of 30 or less, 31–70, and greater than 70, respectively. Change from morning VAS score had no apparent influence on patient-controlled analgesic dosing for patients with afternoon values of 30 or less or greater than 70, but changes in VAS scores of at least 10 did discriminate among patients whose afternoon values were between 31 and 70. Conclusions When pain is an outcome measure in research studies, grouping final VAS scores into a small number of categories provides greater clinical relevance for comparisons than using the full spectrum of measured values or changes in value. Seeing an earlier VAS form has no apparent influence on later values.

Intraoperative tachycardia and hypertension are independently associated with adverse outcome in noncardiac surgery of long duration.

Relatively little is known about the influence of intraoperative hemodynamic variables on surgical outcomes. We drew subjects (n = 797) from a study of patients undergoing major noncardiac surgery. The physiological component of the POSSUM (Physiological and Operative Se- verity Score for the enUmeration of Mortality) operative risk stratification index was determined, and intraoperative measurements of heart rate (HR), mean arterial blood pressure, and systolic arterial blood pressure (SAP) were retrieved from computerized anesthesia records. For every 5-min epoch during the surgery, HR, mean arterial blood pressure, and SAP were each classified as low, normal, or high. Negative surgical outcome (NSO) was defined as a hospital stay of >10 days with a morbid condition or death during the hospital stay. Statistical analyses included Mantel-Haenszel tests and multiple logistic regression. There was no significant association between hemodynamic variables and NSO with short operations. In 388 patients with operations longer than the median time of 220 min, NSO occurred in 15.6%. Controlling for POSSUM score and operation time beyond 220 min, both high HR (odds ratio, 2.704;P = 0.01) and high SAP (odds ratio, 2.095;P = 0.009) were associated with NSO in longer operations. Thus, intraoperative tachycardia and hypertension were associated independently with adverse outcomes after major noncardiac surgery of long duration, over and above the risk imparted by underlying medical conditions.

Arterial blood pressure and heart rate discrepancies between handwritten and computerized anesthesia records.

Previous publications suggest that handwritten anesthesia records are less accurate when compared with computer-generated records, but these studies were limited by small sample size, unblinded study design, and unpaired statistical comparisons. Eighty-one pairs of handwritten and computer-generated neurosurgical anesthesia records were retrospectively compared by using a matched sample design. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and heart rate (HR) data for each 5-min interval were transcribed from handwritten records. In computerized records, the median of up to 20 values was calculated for SAP, DAP, and HR for each consecutive 5-min epoch. The peak, trough, standard deviation, median, and absolute value of the fractional rate of change between adjacent 5-min epochs were calculated for each case. Pairwise comparisons were performed by using Wilcoxon tests. For SAP, DAP, and HR, the handwritten record peak, standard deviation, and fractional rate of change were less than, and the trough and median were larger than, those in corresponding computer records (all with P < 0.05, except DAP median and HR peak). Considering together all the recorded measurements from all cases, extreme values were recorded more frequently in computerized records than in the handwritten records. Implications The discrepancies between handwritten and computerized anesthesia records suggest that some of the data in handwritten records are inaccurate. The potential for inaccuracy should be considered when handwritten records are used as source material for research, quality assurance, and medicolegal purposes.

Effect of labor epidural analgesia with and without fentanyl on infant breast-feeding: a prospective, randomized, double-blind study.

Background:The influence of labor epidural fentanyl on the neonate is controversial. The purpose of this study was to determine whether epidural fentanyl has an impact on breast-feeding. Methods:Women who previously breast-fed a child and who requested labor epidural analgesia were randomly assigned in a double-blinded manner to one of three groups: (1) no fentanyl group, (2) intermediate-dose fentanyl group (intent to administer between 1 and 150 &mgr;g epidural fentanyl), or (3) high-dose epidural fentanyl group (intent to administer > 150 &mgr;g epidural fentanyl). On postpartum day 1, the mother and a lactation consultant separately assessed whether the infant was experiencing difficulty breast-feeding, and a pediatrician assessed infant neurobehavior. All women were contacted 6 weeks postpartum to determine whether they were still breast-feeding. Results:Sixty women were randomly assigned to receive no fentanyl, 59 were randomly assigned to receive an intermediate dose, and 58 were randomly assigned to receive high-dose fentanyl. On postpartum day 1, women who were randomly assigned to receive high-dose fentanyl reported difficulty breast-feeding (n = 12, 21%) more often than women who were randomly assigned to receive an intermediate fentanyl dose (n = 6, 10%), or no fentanyl (n = 6, 10%), although this did not reach statistical significance (P = 0.09). There was also no significant difference among groups in breast-feeding difficulty based on the lactation consultant’s evaluation (40% difficulty in each group; P = 1.0). Neurobehavior scores were lowest in the infants of women who were randomly assigned to receive more than 150 &mgr;g fentanyl (P = 0.03). At 6 weeks postpartum, more women who were randomly assigned to high-dose epidural fentanyl were not breast-feeding (n = 10, 17%) than women who were randomly assigned to receive either an intermediate fentanyl dose (n = 3, 5%) or no fentanyl (n = 1, 2%) (P = 0.005). Conclusions:Among women who breast-fed previously, those who were randomly assigned to receive high-dose labor epidural fentanyl were more likely to have stopped breast-feeding 6 weeks postpartum than woman who were randomly assigned to receive less fentanyl or no fentanyl.

The natural history of type B Niemann-Pick disease: Results from a 10-year longitudinal study

Objectives. Type B Niemann-Pick disease (NPD-B) caused by acid sphingomyelinase deficiency is a rare, autosomal recessive, lysosomal storage disorder with a broad range of disease severity. The objectives of this study were to document the natural history of the disease in a large, clinically heterogeneous patient population that was followed for a period of 10 years and to determine how genotype influences phenotype. Methods. Twenty-nine patients with NPD-B had serial evaluations at least 9 months apart. Organ volumes, hematologic indices, lipid concentrations, pulmonary function, and hepatic activity were studied, and individual phenotypic severity was compared with genotype. Results. All patients with intact spleens had splenomegaly (mean value: 12.7 multiples of normal [MN]; range: 4.5–27.3 MN), and all but 1 had hepatomegaly (mean volume: 1.91 MN; range: 0.93–3.21 MN). At initial visit, 39% had thrombocytopenia and 3% had leukopenia. At final visit, the percentages increased to 54% and 34%, respectively. Mean annual decreases in platelet count and leukocyte count were 7 × 103 and 0.2 × 103 per mm3, respectively. The typical atherogenic lipid profile was worse in older patients. A total of 69% of patients had low diffusion capacity for carbon monoxide, and more than one third had low forced expiratory volume in 1 second, forced vital capacity, and forced expiratory volume in 1 second/forced vital capacity at initial visit. All measurements of pulmonary function showed a gradual deterioration over time. Liver dysfunction was characterized by stable elevation of hepatic transaminases and bilirubin. Homozygotes for ΔR608, P323A, and P330R had milder disease than patients with all other genotypes. Conclusions. The natural history of NPD-B is characterized by hepatosplenomegaly with progressive hypersplenism, worsening atherogenic lipid profile, gradual deterioration in pulmonary function, and stable liver dysfunction.

Quality of analgesia when air versus saline is used for identification of the epidural space in the parturient.

Background and Objectives Identification of the epidural space is often performed using the loss-of-resistance technique (LOR), commonly with air or saline. The effect of air or saline on the quality of labor epidural analgesia has not been adequately studied. Methods Women who requested labor epidural analgesia were randomly assigned to 1 of 2 groups depending on the syringe contents used for the LOR technique and injected into the epidural space. In the air group (n = 80) the anesthesiologist used 2 mL of air, and in the saline group (n = 80) the anesthesiologist used 2 mL of 0.9% saline. After LOR was obtained, a multiorifice epidural catheter was threaded 5 cm into the epidural space and 13 mL of bupivacaine 0.25% was administered in divided doses. The success of the epidural block was determined by asking the patient if she required additional medication 15 minutes later. The occurrence of paresthesias and intravascular or subarachnoid catheters was noted. Results In the air group, 36% of patients requested additional pain medication, and in the saline group 19% requested additional medication (P = .022). We were not able to find a statistically significant difference between groups in the incidence of paresthesias (42% air v 51% saline), intravascular catheters (5% air v 8% saline), or subarachnoid catheters (0 in both groups). Conclusions Using 0.9% saline for the LOR technique is associated with better analgesia as compared with air for labor analgesia, and this advantage should be considered when selecting the syringe contents for the LOR technique.

Progression to Colorectal Neoplasia in Ulcerative Colitis: Effect of Mesalamine

BACKGROUND & AIMS Some studies have suggested that mesalamine can prevent the development of colorectal cancer in patients with ulcerative colitis (UC). The aim of this study was to compare rates of progression with advanced neoplasia in patient cohorts with UC taking low and high doses of mesalamine and to determine where in the process of neoplastic progression mesalamine might act. METHODS Three cohorts of UC patients were identified from an institutional database: 311 patients with no dysplasia (NoD), 56 with indefinite dysplasia (IND), and 26 with flat low-grade dysplasia (fLGD). The impact of mesalamine exposure on the subsequent development of advanced neoplasia (high-grade dysplasia or colorectal cancer) was assessed using life-table methods. RESULTS Seventeen of 311 patients with NoD progressed to advanced neoplasia (5-year rate, 1.1%). This rate was lower than the 5-year rate for the IND (9%; P = .02 vs NoD) and fLGD (45%; P < .001 vs NoD and P = .001 vs IND) cohorts. Among the NoD cohort, the hazard ratio for mesalamine users versus nonusers was 0.70 (95% confidence interval, 0.20-2.44), and for each 1 g/d increase in dose, the hazard ratio was 0.92 (95% confidence interval, 0.58-1.47). For patients with IND, no patients on greater than 2 g/d progressed versus 13.8% on low-dose mesalamine (P = .11). For fLGD, 62.5% on high dose progressed, versus 27.8% on low dose (P = .054). CONCLUSIONS In long-standing UC, patients with fLGD have a higher rate of progression to advanced neoplasia than those with NoD or IND. However, at none of these stages of disease did mesalamine use show definitive chemopreventive activity.

Local anesthetics and mode of delivery: bupivacaine versus ropivacaine versus levobupivacaine.

BACKGROUND:The influence of the labor epidural local anesthetic (LA) on mode of delivery has not been adequately studied. In this study, we sought to determine if there is a difference in mode of delivery among parturients who receive epidural bupivacaine, ropivacaine, or levobupivacaine. METHODS:Nulliparous women at term requesting labor analgesia with a cervical dilation <5 cm were randomized to receive epidural bupivacaine, ropivacaine, or levobupivacaine. Analgesia was initiated with a bolus of 15 mL of 0.0625% of the assigned LA with fentanyl 2 &mgr;g/mL. Analgesia was maintained with an infusion of the same solution at 10 mL/h. The primary endpoint was the operative delivery rate (instrumental assisted vaginal delivery plus cesarean delivery). RESULTS:Ninety-eight women received bupivacaine, 90 ropivacaine, and 34 levobupivacaine (before it was removed from the US market). There was no significant difference in the operative delivery rate (bupivacaine = 46%, ropivacaine = 39%, and levobupivacaine = 32%, P = 0.35) among groups. There was less motor block in the levobupivacaine group when compared with the ropivacaine and bupivacaine groups, P < 0.05. There was no significant difference in the duration of the first or second stage of labor, the total dose of LA received per hour of labor, or neonatal outcome among groups. CONCLUSIONS:Bupivacaine, ropivacaine, and levobupivacaine all confer adequate labor epidural analgesia, with no significant influence on mode of delivery, duration of labor, or neonatal outcome.

Predictive Model for Postoperative Delirium in Cardiac Surgical Patients

Delirium is a common complication following cardiac surgery, and the predictors of delirium remain unclear. The authors performed a prospective observational analysis to develop a predictive model for postoperative delirium using demographic and procedural parameters. A total of 112 adult postoperative cardiac surgical patients were evaluated twice daily for delirium using the Richmond Agitation-Sedation Scale (RASS) and Confusion Assessment Model for the ICU (CAM-ICU). The incidence of delirium was 34% (n = 38). Increased age (odds ratio [OR] = 2.5; 95% confidence interval [CI] = 1.6-3.9; P < .0001, per 10 years) and increased duration of surgery (OR = 1.3; 95% CI = 1.1-1.5; P = .0002, per 30 minutes) were independently associated with postoperative delirium. Gender, BMI, diabetes mellitus, preoperative ejection fraction, surgery type, length of cardiopulmonary bypass, intraoperative blood component administration, Acute Physiology and Chronic Health Evaluation II score, Sequential Organ Failure Assessment score, and Charlson Comorbidity Index, were not independently associated with postoperative delirium.