ISSN NUMBER: 1938-7172
Issue 4.5 VOLUME 4 | NUMBER 5

Editor:
Michael A. Fiedler, PhD, CRNA

Contributing Editors:
Penelope S. Benedik PhD, CRNA, RRT
Joseph F. Burkard, DNSc, CRNA
Mary A. Golinski, PhD, CRNA
Gerard T. Hogan, Jr., DNSc., CRNA
Alfred E. Lupien, PhD, CRNA
Lisa Osborne, PhD, CRNA
Dennis Spence, PhD, CRNA
Steven R. Wooden, MS, CRNA

Guest Editor:
Heather Fields, MSN, CRNA

Assistant Editor
Jessica Floyd, BS

A Publication of Lifelong Learning, LLC © Copyright 2010

New health information becomes available constantly. While we strive to provide accurate information, factual and typographical errors may occur. The authors, editors, publisher, and Lifelong Learning, LLC is/are not responsible for any errors or omissions in the information presented. We endeavor to provide accurate information helpful in your clinical practice. Remember, though, that there is a lot of information out there and we are only presenting some of it here. Also, the comments of contributors represent their personal views, colored by their knowledge, understanding, experience, and judgment which may differ from yours. Their comments are written without knowing details of the clinical situation in which you may apply the information. In the end, your clinical decisions should be based upon your best judgment for each specific patient situation. We do not accept responsibility for clinical decisions or outcomes.

Table of Contents

GENERAL
THE IMPACT OF GLYCEMIC CONTROL AND DIABETES MELLITUS ON PERIOPERATIVE OUTCOMES AFTER TOTAL JOINT ARTHROPLASTY
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EPIDEMIOLOGY OF ANESTHESIA-RELATED MORTALITY IN THE UNITED STATES, 1999-2005
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LAPAROSCOPIC CHOLECYSTECTOMY UNDER SPINAL ANESTHSIA: A STUDY OF 3492 PATIENTS
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EFFECTS OF POSITIVE END-EXPIRATORY PRESSURE ON INTERNAL JUGULAR VEIN CROSS-SECTIONAL AREA IN ANESTHETIZED ADULTS
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REGIONAL ANESTHESIA
PREPUNCTURE ULTRASOUND IMAGING TO PREDICT TRANSVERSE PROCESS AND LUMBAR PLEXUS DEPTH FOR PSOAS COMPARTMENT BLOCK AND PERINEURAL CATHETER INSERTION: A PROSPECTIVE, OBSERVATIONAL STUDY
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OBSTETRIC ANESTHESIA
A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED TRIAL OF EPIDURAL MORPHINE ANALGESIA AFTER VAGINAL DELIVERY
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General

Marchant M, Viens N, Cook D, Vail T, Bolognesi M


 

 

The impact of glycemic control and diabetes mellitus on perioperative outcomes after total joint arthroplasty

J Bone Joint Surg Am. 2009;92:1621-9

Marchant M, Viens N, Cook D, Vail T, Bolognesi M 

 

 

Abstract

Purpose            The purpose of this study was to assess whether or not the ‘quality’ of glycemic control in both insulin dependent and non-insulin dependent diabetic patients was correlated with perioperative complications after total hip and knee replacement surgery. It was hypothesized that irrespective of the type of diabetes, a positive correlation would exist between those with uncontrolled disease and perioperative complications.

Background            Approximately 8% of those undergoing total joint replacement surgeries have a diagnosis of either insulin-dependent or non-insulin dependent diabetes mellitus (DM). The evidence is strong; diabetic patients have higher rates of ‘common surgical’ and ‘systemic complications’ during the perioperative and post-operative periods. What remains inconclusive is the impact that glycemic control has on the outcomes for those undergoing joint arthroplasty specifically. Glycemic control, or lack thereof, is highly associated with outcomes in several other domains such as the acute medical, general surgical, and trauma environments. Research has shown that the physiologic stress even of elective surgery impacts the ability of both the non-diabetic and diabetic individuals to regulate glucose metabolism.

Approximately 46 million people in the United States have a medical diagnosis of arthritis; it remains the leading diagnosis for those having elective joint replacement surgery. With such a high incidence of arthritic patients diagnosed with diabetes undergoing joint replacement procedures, it is important to assess the outcomes of those with controlled diabetes, uncontrolled diabetes, and compare those outcomes with the non-diabetic patient.

Methodology            This was a large nationally representative retrospective comparison study utilizing a national database that is publicly available and devoid of any protected health information. Data was accessed and utilized within the Nationwide Inpatient Sample database inclusive of the dates from 1988 to 2005. It contains discharge information from approximately 7-8 million hospital stays at ~ 1000 hospitals randomly selected to approximate 20% stratified samplings of hospitals across the USA. Total joint arthroplasty and revision-joint arthroplasty were the primary procedure codes used when accessing the data. Those with pathologic fracture, metastatic cancer, infections, or primary malignant neoplasm were excluded. Data was categorized into 3 groups:  patients with controlled diabetes mellitus, those with uncontrolled diabetes mellitus, and non-diabetic patients. The main outcome measures included:

 

  • Peri operative complications
    • Stroke
    • Pneumonia
    • MI
    • Thombophlebitis
    • DVT
    • UTI
    • Ileus
    • Altered mental status
    • Operative infections or other wound problems
    • Postoperative hemorrhage/shock
    • Tranfusions
    • Fractures
    • Hip dislocations and/or sciatic injury
  • Mortality
  • Length of hospital stay
  • The hospital disposition (routine or not, discharge)
  • Hospital charges

In addition, patient specific demographic data was included as well as each patient’s co-morbidities. Comparative statistics for all three cohorts included the appropriate demographics. Additionally, differences in the numbers of perioperative complications and the variables listed above were compared between the 3 groups.

Result            The researchers identified 920,555 non-diabetic patients, 105,485 with controlled diabetes mellitus, and 3,973 patients with uncontrolled diabetes. Regression modeling of controlled and uncontrolled diabetes against the reference variables of no diabetes while adjusting for specific demographic variables revealed the following:

§  Those with controlled DM

o    were significantly less likely to have a routine discharge, and were more likely to have a complication related to UTI and transfusion

o   Were significantly less likely to have an MI

§  Those with uncontrolled DM

o    were significantly more likely to have a complication such as mortality, stroke, UTI, ileus, infection, postoperative hemorrhage or shock, and transfusion

Significant differences were also found among the 3 groups regarding length of stay (LOS) and inflation-adjusted hospital charges; patients with uncontrolled DM had longer LOS and greater charges. In comparing the uncontrolled DM patient with the controlled DM patient, those with uncontrolled DM had: significantly greater odds of CVA, UTI, ileus, infection, postoperative hemorrhage or shock, transfusion, and death. They also had a significantly greater LOS.

A comparison was also done for those with type I and type II diabetes using those with the controlled disease as the reference variable. The following was significant:

  • Uncontrolled Type I were more likely to have a stroke, UTI, and longer LOS compared to controlled type I persons
  • Uncontrolled Type II were significantly more likely to have a stroke, UTI, ileus, thrombophlebitis, postoperative hemorrhage, infection, and longer LOS compared to those with controlled Type II disease

Conclusion            This outcomes study evaluated glycemic control as a predictor of perioperative complications in those undergoing joint replacement surgeries. The research confirmed the hypothesis. Irrespective of type of diabetes, those with uncontrolled disease had significantly more perioperative complications compared to those with controlled disease or those without diabetes.

 

Comment            We as anesthesia providers have a significant contribution to make and a significant responsibility to uphold towards preventing post operative surgical site infections and impaired wound healing. One way in which we do this is by following the most current recommendations regarding glycemic control of the diabetic patient. It is imperative that we know our institutions guidelines, algorithms, policies and procedures regarding the treatment of the diabetic patient during the perioperative period. We should be monitoring, assessing, treating, and following up on a consistent and regular basis. If you are unsure of your institution’s guidelines and/or policies or they have not been developed yet, gain the support of your team members and get the task completed. The evidence has become more and more conclusive that maintaining tighter control of blood glucose levels during the perioperative period does indeed prevent or lessen the severity of post operative surgical site infections.

 

Mary A. Golinski, PhD, CRNA

 

 

The determination of the quality of glycemic control, or the establishment of controlled versus uncontrolled disease, is dependent on more than one variable. The American Diabetes Association guidelines offer the following when assessing whether a patient is controlled or not regarding their diabetes management-- utilize a combination of 1) patient’s self monitoring of blood glucose levels; 2) the current hemoglobin A1c level; and 3) the presence and severity of diabetes-related co-morbidities.

When obtaining information from the patient regarding their self monitoring, the ADA also suggests that ‘control’ can be identified by a pre-prandial capillary plasma glucose level of 90 to 130 mg/dL, and a peak postprandial capillary plasma glucose level of <180 mg/dL.

 The hemoglobin A1c level, or glycosylated or glycated hemoglobin, is a serologic marker that provides an average glucose concentration in the bloodstream for the previous one to three months. Recommendations from the ADA suggests that adults with diabetes have a hemoglobin A1c level <7% (normal 4%-7%). It is a good indicator of long term glycemic control.

Polymorphonuclear granulocytes represent the host’s first defense barrier against bacterial agents. Alterations in chemotaxis, phagocytosis, immunoglobulin production and complement functions occur in the diabetic patient. Polymorphonuclear granulocyte cells of those with diabetes have reduced chemotaxis especially when the diabetes is poorly controlled.

© Copyright 2010 Anesthesia Abstracts · Volume 4 Number 5, May 31, 2010





Li G, Warner M, Lang BH, Huang L, Sun LS


 

Epidemiology of anesthesia-related mortality in the united states, 1999-2005

Anesthesiology 2009;110:759-765

Li G, Warner M, Lang BH, Huang L, Sun LS

 

 

Abstract

Purpose            The purpose of this investigation was to quantify the risk of death related to anesthesia and contrast it with historic reports of anesthesia-related mortality.

Background            The rate of death directly or partially attributable to anesthesia has been tracked for many years in the USA, Europe, Japan, and Australia. Anesthesia-related death rates have steadily declined over time. In the 1940’s, anesthesia-related deaths were reported as 1 in 1,000 procedures (0.1%). In the late 1940’s and early 1950’s a study of almost 600,000 surgical patients reported the anesthesia-related death rate as 64 deaths per 100,000 procedures (0.064%). In that study, there was a great deal of variability in death rate by the anesthetic agent and patient characteristics. In the 1970’s anesthesia-related deaths were reported as 1 in 10,000 procedures (0.01%). In the 1990’s and early 2000’s anesthesia-related deaths were reported as 1 in 100,000 procedures (0.001%). Unfortunately, there is no systematic monitoring of anesthetic complications in the USA. As a consequence, anesthesia-related death rates are only intermittently available. Different methods of calculating anesthesia-related mortality in each study limit the ability to compare their results.

Methodology            This retrospective study used mortality data from the National Vital Statistics System, National Center for Health Statistics. This data set includes only deaths that occurred in the USA. International Classification of Disease, 10th revision (ICD-10) codes were used to determine the cause(s) of death from 1999 through 2005. The number of anesthesia-related deaths that occurred in hospital inpatients was estimated. The total number of surgical patients was derived from the National Hospital Discharge Survey. (This number was used as a proxy for the actual number of anesthetics delivered during the study period.)

Result            The study period was seven years long and included nearly 106 million surgical patients. During the study period there were 2,211 anesthesia-related deaths (0.0021%). Anesthetic complications were the direct cause of 241 deaths (10.4% of all anesthesia-related deaths) and a contributing factor in 1,970 deaths (89.1% of all anesthesia-related deaths). Slightly over half of anesthesia-related deaths were in the 25 year to 54 year old category. Men were almost twice as likely to have had an anesthesia-related death than women.

Deaths directly caused by anesthesia were attributed most often to adverse effects of anesthesia when used therapeutically, 79.7%; then anesthesia complications during pregnancy, 19.1%; and “wrongly placed” endotracheal tubes, 1.2%.

Overall, 46.6% of deaths caused by or contributed to by anesthesia were attributed to anesthetic overdose. The remaining factors identified as causing or contributing to an anesthesia-related death were adverse effects of anesthesia when used therapeutically, 42.5%; anesthesia complications during pregnancy, 3.6%; and “other” complications of anesthesia, 7.3%. Failed or difficult intubation accounted for only 2.3% of all deaths caused by or contributed to by anesthesia. 

 

Table 1           Percent Anesthesia-Related Mortality Rate by Year

anesthesia mortality

Data from Li G, et. al. - Anesthesiology; 110:759-765

 

 

Conclusion            Anesthesia-related deaths have decreased 97% since about 1950. The risk of anesthesia-related mortality for surgical inpatients appeared to be 0.82 in 100,000 (0.00082%).

 

Comment

Studies like this can be tremendously helpful because they tell us whether or not we are improving the safety of anesthesia over time. They also tell us where we need to apply more effort to make anesthesia safer. Unlike some European countries, the USA does not have a systematic reporting system in place that continuously gathers data on anesthesia outcomes and complications. As a result, the information we get on anesthesia morbidity and mortality is unlikely to be gathered in the same way each time. That makes it hard to compare from one study to the next.

This study has some important limitations. For example, how were the “anesthesia-related” causes of death assigned? Since this was a retrospective look at a federal database, the cause of death was most likely assigned by the surgeon. Anesthesia would have had little or no part in assigning the cause of death. This makes me question the accuracy of the anesthesia-related causes of death. For example, I’m skeptical that “overdose of anesthetics” really played a part in almost half of all perioperative deaths. There are five ICD-10 codes for overdose of anesthetics; 19% of all anesthesia-related deaths were attributed to overdose of intravenous anesthetics and 10.5% to overdose of inhaled anesthetics. That simply doesn’t track with what I’ve seen in 25 years of clinical practice.

On the other hand, it seems to me that failed intubation resulting in death is a pretty concrete event that is likely to have been reported accurately. We worry quite a bit about failed intubations, and for good reason, but apparently all our attention to this area is paying off. It is reassuring that this study reported only 2.3% of anesthesia-related deaths were related to “failed or difficult intubation.”

A large number of procedures are now performed outside of hospital based operating suites. The anesthesia-related death data we have comes almost exclusively from hospital based studies. As a result, what we know about anesthesia-related death rates may not be generalizable to settings outside the traditional hospital OR.

 

Michael Fiedler, PhD, CRNA

 

 

© Copyright 2010 Anesthesia Abstracts · Volume 4 Number 5, May 31, 2010





Sinha R, Gurwara AK, Gupta SC


 

Laparoscopic cholecystectomy under spinal anesthsia: a study of 3492 patients

J Laparoenodsc Adv Surg Tech A. 2009;19:323-7

Sinha R, Gurwara AK, Gupta SC

 

Abstract

Purpose            The purpose of this study was to compare complications following spinal anesthesia (SA) to those following general anesthesia (GA) for laparoscopic cholecystecomy (LC) surgery.

Background            Laparoscopic surgery is not typically thought of as a procedure that would utilize SA. However, there are many benefits to using SA instead of GA for LC. Muscle relaxation, analgesia, uneventful postoperative recovery, and avoidance of the complications of GA are some of the benefits of SA. The institution in the study used SA unless the patient preferred GA or SA was contraindicated for LC surgery.

Methodology            In this retrospective, non-randomized study, SA was offered to all patients scheduled for a laparoscopic cholecystectomy. Patients who preferred GA or had a contraindication to SA, which included clotting disease; spinal deformity; and skin pathology overlying the SA site, were used as the control group.

A total of 3,492 patients received SA for abdominal laparoscopic surgery. Of those, 1,049 patients had acute cholecystitis, 2,283 had elective cholecystectomy, and 160 had their laparoscopic cholecystectomy along with some other open or laparoscopic abdominal surgery. The control group included 583 patients.

Prior to SA, patients received a 1,000 mL bolus of D5NS and an intramuscular injection of glycopyrollate 0.2 mg, diazepam 10 mg (or midazolam 2-5 mg), and diclofenac 75 mg. The spinal was placed in the L1-L2 intervertebral space with a 24 or 25 gauge lumbar puncture needle. If surgical time was expected to be less then 30 minutes, 5% lidocaine 1.6-1.8 mL (2mg/kg) was administered. If a longer surgical time was expected, then 3-4 mL of bupivacaine (5 mg / mL with sodium chloride 8 mg/mL) was administered. Clonidine 30 µg was added to the spinal drug to increase the duration of effect.

For five minutes, the patient was positioned in a head-down tilt of 10-20 degrees to reach a segmental level of T4-T5. Monitoring included blood pressure, SpO2, SpCO2, heart rate, and anxiety, which was defined as anxiety that resulted in the conversion to GA. If the SpO2 dropped below 95%, oxygen was administered at 5 L/min through a ventimask. Patients complaining of pain were given tramadol 25 mg or pentazocine 15 mg slow intravenous (IV) or in a drip. Ketamine 25 mg slow IV was used if pain was not resolved. If anxiety was not relieved, the anesthesia was converted GA. A decrease in heart rate below 50 beats/min was treated with 0.3 mg atropine IV or 0.2 mg glycopyrrolate. Blood pressure decreases greater than 20% of the original blood pressure were treated with 3-6 mg mephentermine IV intermittently with a maximum dose of 15 mg. After that, hypotension was managed with dopamine 4-6 µg/kg/min until blood pressure was stable.

The laparoscopic cholecystectomy was performed with three to four ports and intraperitoneal pressures between 8 and 10 mm Hg. The port sites were not injected with local anesthetic. Operative site pain, urinary retention, headache, biliary leak, and port-site infection were the post-operative parameters compared between the SA group and the control group.

Result            In the SA group, 700 patients (20 %) had hypotension and 429 (12 %) experienced neck and/or shoulder pain. Conversion to GA due to anxiety was required for 14 patients and conversion due to a failed spinal in an additional 4 patients. Elective operative time averaged 16.4 and 13.2 minutes for SA and GA respectively. Emergency operative time was 27.4 and 29.1 minutes respectively.

Patients who received GA had more vomiting (30.3 %) than the SA group (2.3 %). In the SA group, 10 patients (0.29 %) experienced urinary retention requiring catheterization compared to 0.01 % of patients in the GA group. The SA group required less injectable pain medication  than the GA group, 34.4 % of SA patients vs. 91.5 % of GA patients. Fourteen patients (0.4 %) in the SA group had port site infections compared to 3 patients (0.5 %) in the GA group. In the SA group, 206 (5.9%) had postural headaches that lasted for an average of 2.6 days. Lying down and increased intake of fluids and salt was used to treat these headaches. Discharge was 2.3 and 3 days in SA and GA patients respectively.

Conclusion            Spinal anesthesia was a viable option for laparoscopic surgery, especially in patients that were not ideal candidates for GA or in areas where GA is not available.

 

Comment

This study opened my eyes to the possibility of using spinal anesthesia for a laparoscopic case. However, I am not totally convinced. The study did not disclose what the patients undergoing GA received. I found myself wondering what pain medication GA patients received perioperatively, if any, that would compare to the medication that the SA group received when they complained of discomfort. Did that 12% of the SA group that required medication perioperatively make up part of the group that did not need pain medication postoperatively? Also, all of the SA group received clonidine in their spinal to increase the duration of effect. But, we all know that clonidine works on alpha-2 receptors in the spinal cord to modulate pain pathways and produce analgesia. I would think that this also made a difference. I wanted to know what antiemetic the GA patients received, if any. Since those were the most significant benefits to using SA presented, I found it difficult to make a comparison. The authors giving us the information about the GA could have made it easier to draw our own conclusion. In the end, the authors say that the most important advantage to SA for laparoscopic cholecystectomy is being able to do laparoscopic surgery in a rural setting where GA is not available and maybe that was the only point that they were trying to make.

While it would surely take a surgeon who was mindful of the patient’s comfort during the procedure, spinal anesthesia for laparoscopic procedures may be useful in patients who strongly prefer not to have a general anesthetic or patients with pathology that makes general anesthesia unsafe for them. It is good to know that spinal anesthesia can be used successfully for laparoscopic procedures.

 

Heather Fields, MSN, CRNA

© Copyright 2010 Anesthesia Abstracts · Volume 4 Number 5, May 31, 2010





Hollenbeck KJ, Vander Schuur BM, Tulis MR, Mecklenburg BW, Gaconnet CP, Wallace SC, Lujan E, Lesnik IK


 

 

Effects of positive end-expiratory pressure on internal jubular vein cross-sectional area in anesthetized adults

Anesth Analg 2010;110:1669-73

Hollenbeck KJ, Vander Schuur BM, Tulis MR, Mecklenburg BW, Gaconnet CP, Wallace SC, Lujan E, Lesnik IK

 

 

Abstract

Purpose            The purpose of this study was to determine if the application of positive end-expiratory pressure (PEEP) of 10 cm H2O to a population of anesthetized adult patients would increase the cross-sectional area (CSA) of the right internal jugular vein (RIJV).

Background            Over 5 million central venous catheters are placed annually in the United States. However, unsuccessful cannulation of the central venous system can range from 5% to 15%, with some literature reporting unsuccessful initial attempts exceeding 35%. Although not commonly considered a serious complication, the potential for carotid artery puncture is increased when multiple attempts are executed during RIJV access. Recent research suggests the use of ultrasound and dynamic maneuvers such as application of PEEP increased the size and reduced the number of needle passes needed to cannulate the RIJV in pediatric patients. Therefore, this study sought to reproduce similar results in an adult population.

Methodology            A total of 45 adult ASA I and II patients were enrolled. All subjects received a 500 mL bolus of IV fluid, followed by a standardized, weight-based intravenous induction. Following intubation, subjects were mechanically ventilated with a tidal volume 6-8 mL/kg, respiratory rate 10-12 breaths/min, I:E ratio 1:2, and PEEP 0 cm H2O. Patients were then positioned on the operating table in a level orientation with the head rotated approximately 20 degrees to the left for RIJV exposure. Five minutes following initiation of mechanical ventilation, the RIJV was visualized using a linear (5-13 MHz) ultrasound probe at the level of the cricoid cartilage. Internal jugular vein cross sectional area, transverse, and anterior-posterior diameters were measured and recorded. Two minutes later PEEP 10 cm H2O was applied and a second set of measurements were obtained. The primary outcome was change in RIJV CSA, transverse, and anterior-posterior diameters.

Result            A total of 45 subjects were enrolled in this prospective, observational study (n = 28 men and n = 17 women; BMI: 26.6 ± 4.1 kg/m2; IVF (mL/kg): 7.4 ± 1.7). On a mL per Kg basis, women received significantly more IV fluid bolus than men (men: 6.8 ± 1.2 vs. women: 8.6 ± 1.8; P <0.05). The RIJV was easily visualized in all subjects. There was a significant increase of 41% ± 48% (median 30%) in the CSA of the RIJV in all subjects following the application of 10 cm H2O PEEP (P < 0.001). Likewise, the transverse and anteroposterior diameters increased in measurement, both achieving significance with relative change being 13% ± 17% (median: 9%) and 24% ± 26% (median: 15%), respectively. Lastly, the application of PEEP 10 cm H2O decreased the mean arterial pressure by -9.9 ± 13.2% (median: -9.3%; P < 0.001), however, no subject required vasoactive medications.

Conclusion            This study showed the single application of PEEP 10 cm H2O in a healthy patient population being mechanically ventilated not only significantly increased CSA, it also increased the transverse and AP diameters of the RIJV. This increasing diameter could potentially improve provider success during RIJV access, as well as offering the provider another maneuver when patient conditions might contraindicate the Trendelenburg position.

 

Comment

I found this study quite interesting considering how often I utilize PEEP on my patients with really no previous consideration to the possible benefits of vessel filling on central line placement. Although ultrasonography has greatly improved successful line placement, a simple mechanism to increase vessel diameter seems very logical and beneficial, especially when training students. I would be interested to see the benefit (i.e., procedure duration, complications) this simple maneuver might have on the actual placement of RIJV access in patients. I would be curious to see if the addition of 10 cm H2O PEEP increases the RIJV size over and above what is seen with Trendelenburg positioning alone. Additionally, in clinical practice it would be important to monitor and consider treating the blood pressure response to the addition of 10 cm H2O PEEP given there was a drop in the mean arterial blood pressure in this study.

One limitation of this study was the lack of weight-based IV fluid bolus, which resulted in significantly larger mL/kg fluid bolus in women. This may have attributed to a relatively greater increase in the CSA in women (50 ± 65%) as compared to men (36 ± 34%).

From a practical standpoint, when using ultrasonography to assist in RIJV line placement it is important to watch how much pressure is applied, as the RIJV can be easily compressed. Additionally, I think it is important to use the doppler mode on the ultrasound machine to identify the vessels (i.e., carotid and internal jugular vein) to minimize risk of carotid artery puncture.

 

Dennis Spence, PhD, CRNA

 

 

 

I would like to thank Eric Bopp, MS, CRNA for assistance in writing this abstract.

 

The views expressed in this article are those of the author and do not reflect official policy or position of the Department of the Navy, Department of Defense or the United States Government.

 

© Copyright 2010 Anesthesia Abstracts · Volume 4 Number 5, May 31, 2010




Regional Anesthesia

Ilfield BM, Loland VJ, Mariano ER


 

 

Prepunture ultrasound imaging to predict transverse process and lumbar plexus depth for psoas compartment block and perineural catheter insertion: a prospective, observational study

Anesth Analg 2010;110:1725-8

Ilfield BM, Loland VJ, Mariano ER

 

 

Abstract

Purpose            This study evaluated the accuracy of prepuncture ultrasound imaging of the transverse process depth prior to performing a psoas compartment block, as well as estimating the actual needle-to-plexus distance.

Background            Traditional techniques used to perform the psoas compartment block rely upon external landmarks, paresthesias, and/or electrical stimulation with an insulated needle. However, no method allows the provider to accurately estimate the location or depth of the transverse process or lumbar plexus. Pre-procedural ultrasound scanning can assist not only in visualizing the transverse process, but measure the distance to this important anatomical landmark.

Methodology            This prospective, observational study recruited patients scheduled for unilateral hip arthroplasty that desired continuous posterior lumbar plexus blockade for postoperative analgesia. Subjects were positioned in the lateral decubitus position with the surgical hip superior. External landmarks were marked in a standard fashion.  A linear array ultrasound (US) probe (6 to 13 MHz) was placed in the sagittal plane to identify the spinous process. Next, the probe was moved lateral to identify the hyperechoic transverse processes.  Measurements were made from skin to transverse process using built-in calipers.

Following preparation of the ultrasound equipment and sterile site preparation, an 18-gauge, insulated needle with bevel caudad was oriented perpendicular to the skin in the parasagittal plane. The nerve stimulator set at 1.2 mA and 2 Hz.  The needle was advanced until the transverse process was contacted and/or lumbar plexus was located, at which time the investigators recorded the depth of the needle to each location.  If the transverse process was contacted prior to locating the lumbar plexus, the provider withdrew the needle 2-3 cm and redirected caudad until the lumbar plexus was identified.  The lumbar plexus was identified by a quadriceps femur contraction and patellar motion after the nerve stimulator was decreased to 0.2 to 0.4 mA.  Following lumbar plexus identification, 15 mL D5W was administered, a single orifice catheter was threaded, and the needle was withdrawn.  A total of 15 mL of 2% mepivacaine with epinephrine 5 mcg/mL was injected through the catheter. The investigators recorded successful placement if the patient reported decreased sensitivity to cold temperature over the thigh and exhibited weakness with knee extension.

Result            A total of 53 subjects were enrolled (men: n = 26; women: n = 27; median age: 52 (21-83), median BMI (kg/m2): 26 (15-37)). In three subjects (6%) the investigators were unable to identify the transverse processes (BMI was 35, 37 and 39 kg/m2).  In n = 50 subjects the distance from skin to the transverse process ranged from 3.5-7.0 cm (median = 5.0 cm).  In n = 27 (54%) subjects the transverse processes were located directly anterior to the intercristal line, and the transverse process was contacted by the needle within a median of 0.5 cm (range: 0-1.0 cm) of the US predicted depth.  In the remaining n = 23 subjects (46%) in whom the transverse process did not lie directly anterior to the intercristal line by ultrasound, the needle did not contact the process before electrical stimulation of the lumbar plexus. In 50 subjects in which the transverse process was located by US, the needle depth to the lumbar plexus was a median of 2.5 cm (0.2-4.0 cm) past the US estimated transverse process depth (median needle depth to lumbar plexus stimulation: 7.5 cm (5.0-9.5 cm)). The perineural catheter could not be advanced past the needle tip in 37 subjects (74%). In all 50 subjects in whom the transverse process was identified, sensory and motor block occurred within 15 minutes of the local anesthetic bolus.

Conclusion            This study demonstrated that prepuncture US prior to performing a psoas compartment block can predict transverse process depth to within 1.0 cm, and that the lumbar plexus lies approximately 4 cm past the process depth. Using US to identify the location and depth to the transverse process may help reduce the risks associated with lumbar plexus blockade. This is especially significant given external landmarks do not accurately predict lumbar plexus depth.

 

Comment

This article clearly demonstrates the usefulness of ultrasound in regional anesthesia.  This particular block is of great value to any provider who provides anesthesia for hip procedures (i.e., hip arthroplasty and arthroscopy), because it provides excellent postoperative analgesia. However, because of the potential complications associated with this block it is considered an advanced block, and is thus more difficult to teach students or other providers with little to no experience with regional anesthesia.  Therefore, I hope this article can encourage providers to consider incorporating ultrasound technology into their practice to not only reduce potential complications, but to provide them with added confidence and awareness of the depth of the lumbar plexus. 

It is important to point out that investigators used a linear array probe which provides better image quality for superficial structures. A curved array US probe (2 to 5 MHz) is a better probe because it can identify deeper structures, however image quality is poor. The investigators stated when they started the study they did not have a curved array probe, and they believe this type of probe may have helped identify the transverse process in the three subjects with a BMI >35 kg/m2. Therefore, anesthesia providers may want to consider using a curved linear probe for obese patients when performing prepuncture ultrasound scanning for a lumbar plexus block.

 

Dennis Spence, PhD, CRNA

 

 

1.     Capdevilla X, Macaire P, Dadure C, Choquet O, Biboulet P, Ryckwaert Y, D’Athis F. Continuous psoas compartment block for postoperative analgesia after total hip arthroplasty : new landmarks, technical guidelines, and clinical evaluation. Anesth Analg 2002;94:1606-13.

 

 

The lumbar plexus block requires identification of several external landmarks prior to placement of the block. The authors of this study referenced the Capdevilla at al.1 article when describing their landmarks. For this current study all patients were positioned in the lateral decubitus position with the operative hip superior.  The line connecting the apex of the iliac crests was drawn on the patient, followed by a perpendicular and bisecting line in the sagittal plane over the spinous processes (midline).  Another line, in the parasagittal plane, was completed crossing over the superior iliac crest.  The intercristal line located between the two bisecting lines was divided into thirds, and a skin wheal raised 0.75 cm medial to the intersection between the middle and lateral marked thirds of the intercristal line.

 

I would like to thank Eric Bopp, MS, CRNA for assistance in writing this abstract.

 

The views expressed in this article are those of the author and do not reflect official policy or position of the Department of the Navy, Department of Defense or the United States Government.

© Copyright 2010 Anesthesia Abstracts · Volume 4 Number 5, May 31, 2010




Obstetric Anesthesia

Macarthur A, Imarenglaye C, Tureanu L, Downey K.


 

A randomized, double-blind, placebo-controlled trial of epidural morphine analgesia after vaginal delivery

Anesth Analg 2010;110:159-164

Macarthur A, Imarenglaye C, Tureanu L, Downey K.

Abstract

Purpose            The purpose of this study was to compare the opioid requirements in women after vaginal delivery who received either epidural morphine 2.5 mg or placebo.

Background            Perineal trauma after vaginal delivery can be very distressing and is associated with significant pain. It can also interfere with activities such as sitting and urinating. Nonsteriodal anti-inflammatory drugs and acetominophin are commonly prescribed for perineal pain, however systemic opioids may be required for third or fourth-degree lacerations. In low doses, epidural morphine provides excellent analgesia with minimal side effects after cesarean delivery, however it is not routinely used after vaginal delivery to treat perineal pain.

Methodology            This was a randomized, double-blind, placebo-controlled trial. Women were randomized to receive either 2.5 mg epidural morphine diluted in 10 mL normal saline or placebo after vaginal delivery. Randomization was stratified for primiparous and multiparous subjects.

Epidural infusions were not standardized for study patients. Typical bolus doses included 0.1-0.125% bupivacaine with fentanyl 50-100 mcg followed by a patient controlled epidural analgesic of 0.0625% bupivacaine with fentanyl 2 mcg/mL between 8 and 12 mL/hr, with demand dose of 5 mL every 5-10 minutes. After vaginal delivery, all patients received 1,000 mg acetaminophen every 6 hours and 400 mg ibuprofen every 6 hours. For breakthrough pain codeine 30-60 mg every 6 hours or IM morphine 5-10 mg every four hours was administered as needed.

The primary outcome was the proportion of subjects in each group who received opioid analgesics in the first 24 hours after delivery. Secondary outcomes included pain scores, time to first request for pain meds, frequency of side effects (drowsiness, pruritus, urinary retention, nausea, and vomiting) recorded every 4 hours.

Result            Only 442 of 1,110 women who were approached agreed to participate in the study. The majority did not want to receive prophylactic opioids. Of the 442 women who enrolled, 228 had a spontaneous vaginal delivery, with n = 113 randomized to epidural morphine and n = 115 to control group.

Major perineal trauma occurred in 74% of all subjects. In the epidural morphine group 8 of 113 (7%) required supplemental analgesia compared to 37 of 115 (32%) in the control group (P < 0.001). This resulted in a 78% reduction in the need for supplemental analgesia (P < 0.001). Primparous women had the highest frequency of supplemental opioid administration. Only 1 of 37 multiparous women in the epidural group required supplemental opioids in the first 24 hours compared to 8 of 36 in the control group (P < 0.01). Time to supplemental analgesia was delayed by 4 hours in the epidural morphine group (time to analgesia: epidural group 22.9 ± 4 h vs. control group 18.9 ± 8 h, P < 0.001). The incidence of side effects was almost double for all categories in the epidural group, though there were no statistically significant differences between groups (P > 0.05; Table 1). Maternal satisfaction scores were similar between the groups.

 

Table 1. Side Effects

 

Morphine Group

Control Group

 

Pruritus

12/108 (12%)

6/109 (6%)

P=0.10

Nausea

10/107 (9%)

5/109 (5%)

P=0.20

Drowsiness

2/106 (2%)

0/107 (0%)

P=0.25

Urinary retention

20/109 (18%)

11/111 (10%)

P=0.08

Conclusion            Use of 2.5 mg epidural morphine after vaginal delivery reduced the need for supplemental opioids by 78%. Parturients who stay in the hospital for 24 h or more after delivery may benefit from administration of epidural morphine after vaginal delivery.

 

Comment

I must admit I have never given epidural morphine after vaginal delivery. However, after reading this study and talking with a colleague of mine who has had a baby recently, I might consider giving it to select patients. I would probably consider offering it only to patients with major perineal trauma (3rd or 4th degree tears), rather than all patients. The problem with epidural morphine is the side effect profile, with urinary retention (defined as need for straight catherization) being the most frequent side effect next to pruritus. In this study the reason they did not find a difference in the side effect profile was most likely because the study was underpowered to detect differences in side effects. Also the investigators relied on nurses to collect data on side effects, which may have contributed to underreporting of side effects because most OB nurses are not necessarily going to wake a new mom up every 4 hours during the night to ask them if they are itching.

The most important finding the authors discussed was that prior to this study they only offered acetaminophen and ibuprofen on an as needed basis, rather than around the clock. What they found was that the around the clock administration of these two drugs benefitted all subjects, regardless of group, and since completing their study they now prescribe acetaminophen 1,000 mg and ibuprofen 400 mg every 6 hours. This is something I always recommend and typically after cesarean sections I order, assuming there is no contraindication, toradol 30 mg IV every 6 hours until patients can take oral meds, then I order around the clock acetaminophen and ibuprofen.

 

Dennis Spence, PhD, CRNA

 

The views expressed in this article are those of the author and do not reflect official policy or position of the Department of the Navy, Department of Defense or the United States Government.

© Copyright 2010 Anesthesia Abstracts · Volume 4 Number 5, May 31, 2010