Ultrasound imaging facilitates spinal anesthesia in adults with difficult surface anatomic landmarks.

Anesthesiology. 2011 Jul;115(1):94-101

Authors: Chin KJ, Perlas A, Chan V, Brown-Shreves D, Koshkin A, Vaishnav V

Abstract
BACKGROUND: Poor surface anatomic landmarks are highly predictive of technical difficulty in neuraxial blockade. The authors examined the use of ultrasound imaging to reduce this difficulty.
METHODS: The authors recruited 120 orthopedic patients with one of the following: body mass index more than 35 kg/m² and poorly palpable spinous processes; moderate to severe lumbar scoliosis; or previous lumbar spine surgery. Patients were randomized to receive spinal anesthetic by the conventional surface landmark-guided technique (group LM) or by an ultrasound-guided technique (group US). Patients in group US had a preprocedural ultrasound scan to locate and mark a suitable needle insertion point. The primary outcome was the rate of successful dural puncture on the first needle insertion attempt. Normally distributed data were summarized as mean ± SD and nonnormally distributed data were summarized as median [interquartile range].
RESULTS: The first-attempt success rate was twice as high in group US than in group LM (65% vs. 32%; P < 0.001). There was a twofold difference between groups in the number of needle insertion attempts (group US, 1 [1-2] vs. group LM, 2 [1-4]; P < 0.001) and number of needle passes (group US, 6 [1-10] vs. group LM, 13 [5-21]; P = 0.003). More time was required to establish landmarks in group US (6.7 ± 3.1; group LM, 0.6 ± 0.5 min; P < 0.001), but this was partially offset by a shorter spinal anesthesia performance time (group US, 5.0 ± 4.9 vs. group LM, 7.3 ± 7.6 min; P = 0.038). Similar results were seen in subgroup analyses of patients with body mass index more than 35 kg/m and patients with poorly palpable landmarks.
CONCLUSION: Preprocedural ultrasound imaging facilitates the performance of spinal anesthesia in the nonobstetric patient population with difficult anatomic landmarks.

PMID: 21572316 [PubMed - indexed for MEDLINE]

Prognostic value of brain natriuretic peptide in noncardiac surgery: a meta-analysis.

Anesthesiology. 2009 Aug;111(2):311-9

Authors: Ryding AD, Kumar S, Worthington AM, Burgess D

BACKGROUND: The prognostic role of brain natriuretic peptide (BNP) measurement before noncardiac surgery is unclear. The authors therefore performed a meta-analysis of studies in patients undergoing noncardiac surgery to assess the prognostic value of elevated BNP or N-terminal pro-BNP (NT-proBNP) levels in predicting mortality and major adverse cardiovascular events (MACE) (cardiac death or nonfatal myocardial infarction). METHODS: Unrestricted searches of MEDLINE and EMBASE bibliographic databases were performed using the terms "brain natriuretic peptide," "b-type natriuretic peptide," "BNP," "NT-proBNP," and "surgery." In addition, review articles, bibliographies, and abstracts of scientific meetings were manually searched. The meta-analysis included prospective studies that reported on the association of BNP or NT-proBNP and postoperative major adverse cardiovascular event (MACE) or mortality. The study endpoints were MACE, all-cause mortality, and cardiac mortality at short-term (less than 43 days after surgery) and longer-term (more than 6 months) follow-up. A random-effects model was used to pool study results; funnel-plot inspection was done to evaluate publication bias; Cochrane chi-square test and I testing was used to test for heterogeneity. RESULTS: Data from 15 publications (4,856 patients) were included in the analysis. Preoperative BNP elevation was associated with an increased risk of short-term MACE (OR 19.77; 95% confidence interval [CI] 13.18-29.65; P < 0.0001), all-cause mortality (OR 9.28; 95% CI 3.51-24.56; P < 0.0001), and cardiac death (OR 23.88; 95% CI 9.43-60.43; P < 0.00001). Results were consistent for both BNP and NT-proBNP. Preoperative BNP elevation was also associated with an increased risk of long-term MACE (OR 17.70; 95% CI 3.11-100.80; P < 0.0001) and all-cause mortality (OR 4.77; 95% CI 2.99-7.46; P < 0.00001). CONCLUSIONS: Elevated BNP and NT-proBNP levels identify patients undergoing major noncardiac surgery at high risk of cardiac mortality, all-cause mortality, and MACE.

PMID: 19602961 [PubMed - indexed for MEDLINE]

Trends and outcomes of malignant hyperthermia in the United States, 2000 to 2005.

Anesthesiology. 2009 Jan;110(1):89-94

Authors: Rosero EB, Adesanya AO, Timaran CH, Joshi GP

BACKGROUND: Malignant hyperthermia (MH) is a potentially fatal pharmacogenetic disorder with an estimated mortality of less than 5%. The purpose of this study was to evaluate the current incidence of MH and the predictors associated with in-hospital mortality in the United States. METHODS: The Nationwide Inpatient Sample, which is the largest all-payer inpatient database in the United States, was used to identify patients discharged with a diagnosis of MH during the years 2000-2005. The weighted exact Cochrane-Armitage test and multivariate logistic regression analyses were used to assess trends in the incidence and risk-adjusted mortality from MH, taking into account the complex survey design. RESULTS: From 2000 to 2005, the number of cases of MH increased from 372 to 521 per year. The occurrence of MH increased from 10.2 to 13.3 patients per million hospital discharges (P = 0.001). Mortality rates from MH ranged from 6.5% in 2005 to 16.9% in 2001 (P < 0.0001). The median age of patients with MH was 39 (interquartile range, 23-54 yr). Only 17.8% of the patients were children, who had lower mortality than adults (0.7% vs. 14.1%, P < 0.0001). Logistic regression analyses revealed that risk-adjusted in-hospital mortality was associated with increasing age, female sex, comorbidity burden, source of admission to hospital, and geographic region of the United States. CONCLUSIONS: The incidence of MH in the United States has increased in recent years. The in-hospital mortality from MH remains elevated and higher than previously reported. The results of this study should enable the identification of areas requiring increased focus in MH-related education.

PMID: 19104175 [PubMed - indexed for MEDLINE]

A rational approach to perioperative fluid management.

Anesthesiology. 2008 Oct;109(4):723-40

Authors: Chappell D, Jacob M, Hofmann-Kiefer K, Conzen P, Rehm M

Replacement of assumed preoperative deficits, in addition to generous substitution of an unsubstantiated increased insensible perspiration and third space loss, plays an important role in current perioperative fluid regimens. The consequence is a positive fluid balance and weight gain of up to 10 kg, which may be related to severe complications. Because the intravascular blood volume remains unchanged and insensible perspiration is negligible, the fluid must accumulate inside the body. This concept brings into question common liberal infusion regimens. Blood volume after fasting is normal, and a fluid-consuming third space has never been reliably shown. Crystalloids physiologically load the interstitial space, whereas colloidal volume loading deteriorates a vital part of the vascular barrier. The endothelial glycocalyx plays a key role and is destroyed not only by ischemia and surgery, but also by acute hypervolemia. Therefore, undifferentiated fluid handling may increase the shift toward the interstitial space. Using the right kind of fluid in appropriate amounts at the right time might improve patient outcome.

PMID: 18813052 [PubMed - indexed for MEDLINE]

A randomized trial of ultrasound image-based skin surface marking versus real-time ultrasound-guided internal jugular vein catheterization in infants.

Anesthesiology. 2007 Nov;107(5):720-4

Authors: Hosokawa K, Shime N, Kato Y, Hashimoto S

BACKGROUND: Ultrasound-guided central venous catheterization has been recommended to increase the procedural success rate and enhance patient safety. However, few studies have examined the potential advantages of one ultrasound technique with another, specifically in small infants. METHODS: The authors randomly assigned 60 neonates and infants weighing less than 7.5 kg to an ultrasound-guided skin-marking method (n = 27) versus real-time ultrasound-assisted internal jugular venous catheterization (n = 33). The times to successful puncture of the internal jugular vein and to catheterization were measured. Attempts at needle punctures for successful catheterization were counted. Procedural complications were recorded. RESULTS: In the real-time group, compared with the skin- marking group, venous puncture was completed faster (P = 0.03), the time required to catheterize was shorter (P < 0.01), and fewer needle passes were needed. Specifically, fewer than three attempts at puncture were made in 100% of patients in the real-time group, versus 74% of patients in the skin-marking group (P < 0.01). A hematoma and an arterial puncture occurred in one patient each in the skin-marking group. CONCLUSIONS: The real-time ultrasound guidance method could enhance procedural efficacy and safety of internal jugular catheterization in neonates and infants.

PMID: 18073546 [PubMed - indexed for MEDLINE]

Impact of heart failure on patients undergoing major noncardiac surgery.

Anesthesiology. 2008 Apr;108(4):559-67

Authors: Hammill BG, Curtis LH, Bennett-Guerrero E, O'Connor CM, Jollis JG, Schulman KA, Hernandez AF

BACKGROUND: Changes in the demographics and epidemiology of patients with cardiovascular comorbidities who undergo major noncardiac surgery require an updated assessment of which patients are at greater risk of mortality or readmission. The authors evaluated short-term outcomes among patients with heart failure, coronary artery disease (CAD), or neither who underwent major noncardiac surgery. METHODS: Patients were aged 65 and older, had Medicare fee-for-service coverage, and underwent 1 of 13 major noncardiac procedures from 2000 through 2004, excluding patients with end-stage renal disease and patients who did not have at least 1 yr of Medicare fee-for-service eligibility before surgery. Main outcome measures were operative mortality and 30-day all-cause readmission. RESULTS: Of 159,327 procedures, 18% were performed in patients with heart failure and 34% were performed in patients with CAD. Adjusted hazard ratios of mortality and readmission for patients with heart failure, compared with patients with neither heart failure nor CAD, were 1.63 (95% confidence interval, 1.52-1.74) and 1.51 (95% confidence interval, 1.45-1.58), respectively. Adjusted hazard ratios of mortality and readmission for patients with CAD, compared with patients with neither heart failure nor CAD, were 1.08 (95% confidence interval, 1.01-1.16) and 1.16 (95% confidence interval, 1.12-1.20), respectively. These effects were statistically significant. Patients with heart failure were at significantly higher risk for both outcomes compared with patients with CAD. CONCLUSIONS: Elderly patients with heart failure who undergo major surgical procedures have substantially higher risks of operative mortality and hospital readmission than other patients, including those with coronary disease, admitted for the same procedures. Improvements in perioperative care are needed for the growing population of patients with heart failure undergoing major noncardiac surgery.

PMID: 18362586 [PubMed - indexed for MEDLINE]