ISSN NUMBER: 1938-7172
Issue 13.6

Editor:
Michael A. Fiedler, PhD, CRNA

Contributing Editors:
Mary A Golinski, PhD, CRNA
Dennis Spence, PhD, CRNA

Assistant Editor
Heather Whitten, MEd.


A Publication of Lifelong Learning, LLC © Copyright 2019

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

OBSTETRIC ANESTHESIA
Adverse events and factors associated with potentially avoidable use of general anesthesia in cesarean deliveries

Ultrasound-assisted technology versus the conventional landmark location methods in spinal anesthesia for cesarean delivery in obese parturients: a randomized controlled trial

REGIONAL ANESTHESIA
Adding a PECS II block for proximal arm arteriovenous access – a randomised study

None of the editors or contributors have any real or potential conflicts of interest to disclose.

 

This program has been prior approved by the American Association of Nurse Anesthetists for 20 Class A CE credits; Code Number 1037484; Expiration Date 03/31/2022.

Obstetric Anesthesia
Adverse events and factors associated with potentially avoidable use of general anesthesia in cesarean deliveries

Anesthesiology 2019;130:912-22

DOI: 10.1097/ALN.0000000000002629

Guglielminotti J, Landau R, Li G


Abstract

 

Purpose   The purpose of this study was to examine adverse events associated with potentially avoidable use of general anesthesia for C-section.

 

Background   Neuraxial anesthesia significantly reduces the risk of adverse events in women undergoing C-section. Historically, general anesthesia is estimated to be administered in 5.5% of all cesarean deliveries. Identifying ways to reduce this rate may be associated with improved obstetric anesthesia outcomes. This study sought to identify trends, maternal adverse events, and patient and hospital factors associated with avoidable administration of general anesthesia for C-section.

 

Methodology   This was a retrospective study which examined C-section adverse outcomes in patients who did not have an indication for general anesthesia. Adverse events included:

  • anesthesia complications
  • surgical-site infection
  • venous thromboembolism
  • death or cardiac arrest

[Editor’s Note: a link to more specific criteria is at the end of this summary]

 

Clinical indications for general anesthesia included:

  • Obstetric Indications
    • abnormal fetal heart rhythm
    • fetal distress
    • severe postpartum hemorrhage
    • placental abruption
    • placenta previa
    • placenta accrete
    • uterine rupture
    • cord prolapse
    • amniotic fluid embolism
  • Maternal Indications
    • comorbidity index >2
    • Charlson comorbidity index >1
  • Contraindications to Neuraxial Anesthesia
    • coagulation disorder
    • thrombocytopenia
    • sepsis or septic shock
    • maternal fever or generalized infection
    • chorioamnionitis

If a patient received general anesthesia for a failed epidural, the case was coded as general anesthesia. The annual percentage of women delivering with neuraxial anesthesia during labor was used to determine anesthesia provider experience for each hospital. Patient and hospital factors were taken from the New York State Inpatient Database.

 

Statistical analysis was appropriate. Logistic regression was used to identify predictors of adverse outcomes. Temporal trends in general anesthesia were calculated for each 2-year interval in the 12-year study period. Statistical significance was a P < 0.01.

 

Result   The sample included 466,014 cesarean deliveries, with 5.7% of those (26,431) completed under general anesthesia without a documented clinical indication. Overall, 44% of all general anesthetics were considered potentially avoidable. The overall rate of general anesthesia for C-section without an indication decreased from 5.6% in 2003 to 4.8% in 2013 / 2014. This was a 14% decrease. In minority women, however, the rate of general anesthesia for C-section increased from 5.4% in 2003 to 6% in 2013 / 2014. This was an11% increase (P < 0.001). In hospitals with more than 2,500 annual deliveries, no change was seen in the use of general anesthesia without an indication.

 

Avoidable general anesthesia was associated with a:

  • 1.6 times increased odds of anesthesia complications
  • 1.7 times increased odds of surgical site infection
  • 1.9 times increased odds of venous thromboembolism
  • 2.9 times increased odds of severe complications

Avoidable general anesthesia was not, however, associated with an increased risk of death or cardiac arrest.

 

Patient risk factors for avoidable general anesthesia included:

  • age <19 years
  • ethnic minority
  • Medicaid or Medicare insurance
  • preexisting or pregnancy-associated conditions
  • nonelective admission (17% higher odds)
  • weekend admission (6% higher odds)

Hospital-level factors that increased the odds of avoidable general anesthesia included:

  • teaching hospital (29% higher odds)
  • neonatal level-of-care designation 1 (35% higher odds)
  • neonatal level-of-care designation 3 (92% higher odds)
  • lower use of neuraxial techniques during labor (Table 1)
  • higher annual volume of deliveries (≥2,500 per year; 34% higher odds)
  • ≥25% of women delivering with comorbidity index >2 (16% higher odds)

 

Table 1. Odds of Avoidable General Anesthesia vs.
use of Regional for Labor

Neuraxial Anesthesia during Vaginal Delivery

Odds of General

P Value

≥75% (reference standard)

1

50 to 74.9%

1.35

<0.001

25 to 49.9%

1.60

<0.001

≤ 24.9%

3.24

<0.001

 

Conclusion   In this study 44% of general anesthesia cases were potentially avoidable and were associated with more adverse maternal outcomes. Hospitals where neuraxial anesthesia was used less often during labor was the strongest predictor of avoidable general anesthesia for C-section.

 

Comment

 

This study examined cases of avoidable general anesthesia for C-section. Overall, the use of general anesthesia without an indication decreased by 14% over the 12-year study period. The results confirmed what we already know, that general anesthesia is associated with higher rates of adverse events. However, administration of avoidable general anesthesia was not associated with higher rates of mortality in this study. During the study time frame we have seen increased use of video-laryngoscopy devices for airway management, and their use may be associated with lower rates of failed intubation in pregnant women. I always use a video-laryngoscope when I intubate a pregnant women for a C-section.

 

One of the major findings of this study was that hospitals with lower rates of neuraxial anesthesia for vaginal delivery had higher rates of avoidable general anesthesia. They also found higher rates of avoidable general anesthesia on weekends. Hospitals can improve their outcomes if they find ways to increase their epidural rates in laboring patients and ensure that staff working the weekends are proficient at neuraxial anesthesia.

 

Dennis Spence, PhD, CRNA


Note: More detailed data from the original study is available at this link see http://links.lww.com/ALN/B862

 

The original article summarized here is available free full text at the following url: https://anesthesiology.pubs.asahq.org/article.aspx?articleid=2725280

 

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, the Department of Defense, the Uniformed Services University of the Health Sciences, or the United States Government.


© Copyright 2019 Anesthesia Abstracts · Volume 13 Number 6, June 20, 2019





Ultrasound-assisted technology versus the conventional landmark location methods in spinal anesthesia for cesarean delivery in obese parturients: a randomized controlled trial

Anesth Analg 2019;129:155-61

DOI: 10.1213/ANE.0000000000003795

Li M, Ni X, Xu Z, Shen F, Song Y, Li Q, Liu Z


Abstract

 

Purpose   The purpose of this study was to evaluate the effect of a pre-procedural ultrasound to assist with identifying landmarks for spinal anesthesia placement in obese parturients for cesarean delivery.

 

Background   Spinal anesthesia can be difficult in parturients with a high body mass index (BMI). Exaggerated lordosis and edema can make palpation of interspaces difficult. Pre-procedural ultrasonography has been demonstrated to speed up placement of neuraxial anesthesia in sitting parturients. There are, however, limited studies examining the use of pre-procedural ultrasonography to identify the optimal spinal anesthetic insertion point in parturients undergoing cesarean delivery in the lateral position. The investigators hypothesized that use of pre-procedural ultrasonography would improve first-attempt success rates in obese parturients.

 

Methodology   This was a prospective, randomized, controlled trial conducted at a single institution in China. Parturients with a BMI ≥30 Kg/m2 undergoing spinal anesthesia in the lateral position were randomized to either the traditional palpation technique (Palpation Group) or pre-procedural ultrasound (Ultrasound Group). One of three anesthesia professionals with at least 3 years experience performed all spinal blocks. All ultrasound scans were performed by a single anesthesia professional who had performed >150 ultrasound scans for neuraxial block placement in parturients. All spinals were placed midline starting first at L3-4 using 0.5% hyperbaric bupivacaine 3 mL. A maximum of 3 skin punctures (needle withdrawn from the skin and readvanced without changing the interspace) and 5 needle passes (needle withdrawn and redirected without withdrawal from the skin) were allowed at a single interspace before attempting placement at the L2-3 interspace. Successful spinal anesthesia was defined as a bilateral T-4 block 5 minutes after injection.

 

Ultrasound scans were performed in the longitudinal paramedian and transverse midline views to identify midline and the view with the brightest image of the ligamentum flavum. The optimal insertion point was identified as the intersection of longitudinal and transverse skin marks. During the ultrasound scans the anesthesia professionals who were to place the spinals were outside the room.

 

The primary outcome was successful dural puncture on the first attempt. Secondary outcomes were number of skin punctures, number of needle passes, procedure duration, and incidence of complications. A post hoc subgroup analysis was completed to compare outcome differences in parturients with a BMI 30-34.9 Kg/m2, 35-39.9 Kg/m2, and ≥40 Kg/m2.

 

In the Ultrasound Group, the time required to identify the insertion site was the interval from placement of the ultrasound probe to making the skin mark. For the Palpation Group the time was defined as from when the anesthesia professional touched the patient to completion of interspace marking. Spinal placement was defined as the time from skin localization to positive cerebrospinal fluid swirl. Total procedure time was the sum of insertion point identification and spinal placement. A blinded anesthesia professional recorded all outcomes. Sample size calculations and statistical analysis were appropriate. A P < 0.05 was considered significant.

 

Result   A total of 80 subjects were enrolled; 40 in each group. The groups were similar in demographic characteristics. The first-attempt success rate was over 87% in the Ultrasound Group vs. only 52.5% in the Palpation Group (P = 0.001). The number of skin punctures was 3 times greater (3.6 vs. 1.2, P < 0.001), and the number of needle passes was 7 times greater (15 vs. 2, P < 0.001) in the Palpation Group compared to the Ultrasound Group. In the Palpation Group 17 patients required >10 needle passes. Only one patient needed more than 10 needle passes in the Ultrasound Group (P < 0.001). There was no significant difference in the time taken to identify the insertion point between the groups. However, time taken to place the spinal was 79 seconds longer in the Palpation Group (120 s vs. 42 s, P < 0.001). Total procedure time was significantly longer in the Palpation Group, 6.3 min., vs. the Ultrasound Group 4.1 min. (P < 0.001). Forty percent of patients in the Palpation Group required a new interspace attempt vs. no one in the Ultrasound Group (P < 0.001).

 

Subgroup analysis based on BMI category demonstrated that first time success rate was lower and the need for > 10 needle passes was more common in the Palpation Group in subjects with a BMI >35 Kg/m2 (P < 0.001; Figures 1 and 2). Total procedure times were significantly longer in subjects in the Palpation Group with a BMI >35 Kg/m2 (P < 0.001). However, the time for landmark identification was significantly longer for subjects in the Ultrasound Group with a BMI of 30-34.9 Kg/m2. In 8 patients in the Palpation Group the L2-3 interspace was used, with the paramedian approach being required in 4 cases and ultrasound in 2 cases. Each group had one failed spinal requiring rescue analgesia. No complications occurred in either group.

 

Figure 1. First-Attempt Success Rate

 

 

Figure 2. Needle Passes

 

Conclusion   Pre-procedure ultrasound examination reduce the time needed for spinal anesthesia in parturients with a BMI ≥ 35 Kg/m2.

 

Comment

 

The results of this study are not surprising given findings from a previous study examining preprocedural ultrasonography to facilitate spinal placement in adults predicted to be difficult (see Anesthesia Abstracts Issue 5.10). Chin et al1 reported that in patients with a BMI > 35 Kg/mthose in the Ultrasound Group had a 59% first attempt success rate as compared to 30% in the Palpation Group (P = 0.004). For those with difficult or impossible landmarks, the first attempt success rate was 57% in the Ultrasound Group and 30% in the Palpation Group (P = 0.012). In the post hoc analysis no difference was noted in the time taken to perform spinal anesthesia. However, in the overall analysis it took approximately 2 minutes longer to place the spinal anesthetic in the Palpation Group (P = 0.038). The difference between these two studies was that is this current study ultrasound exams occurred in the lateral position by a single anesthesia professional who did not place the spinal. However, in the study by Chin the ultrasound scan and spinal anesthesia were performed by the same provider with at least 5 years of experience and performance of at least 30 preprocedural ultrasound scans for neuraxial anesthesia. The latter study seems more clinically relevant since it reflects what would occur most commonly in practice.

 

Nonetheless, the results are the same- pre-procedural ultrasonography facilitates spinal anesthesia placement and epidural placement2 (see Anesthesia Abstracts Issue 3.7). I encourage readers to learn how to use the technique.

Dennis Spence, PhD, CRNA


1. Chin KJ, Perlas A, Chan V, Brown-Shreves D, Koshkin A, Vaishnav V.Ultrasound imaging facilitates spinal anesthesia in adults with difficult surface anatomic landmarks. Anesthesiology 2011;115: 94-101.

2. Balki M, Halpern S, Carvalho JCA. Ultrasound imaging of the lumbar spine in the transverse position: the correlation between estimated and actual depth to the epidural space in obese parturients. Anesth Analg 2009;108:1876-1881.

 


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, the Department of Defense, the Uniformed Services University of the Health Sciences, or the United States Government.


© Copyright 2019 Anesthesia Abstracts · Volume 13 Number 6, June 20, 2019




Regional Anesthesia
Adding a PECS II block for proximal arm arteriovenous access – a randomised study

Acta Anaesthesiol Scand 2018;62:677-686

DOI: 10.1111/aas.13073

Quek KH, Low EY, Tan YR, Ong ASC, Tang TY, Kam JW, Kiew ASC


Abstract

 

Purpose   The purpose of this study was to compare the effectiveness of an ultrasound-guided subpectoral-serratus anterior fascial plane block (PECS II) combined with a supraclavicular block vs. a supraclavicular block alone for proximal arm arteriovenous graft creation in patients with end-stage renal disease.

 

Background   Regional anesthesia is considered safer than general anesthesia for proximal arm arteriovenous graft creation in patients with end-stage renal disease because it is associated with reduced risk of complications compared to general anesthesia. Unfortunately, the optimal type of regional anesthesia is unknown. Proximal arm graft creation requires blockade of the brachial plexus plus the intercostobrachial nerve which originates from the lateral cutaneous rami of T2-T3. Unfortunately, this nerve is often missed with a supraclavicular block. The PECS II block in conjunction with the supraclavicular block can provide complete blockade of the upper arm for arteriovenous graft and fistula creation because the PECS II reliably blocks the intercostobrachial nerve. No studies have examined the addition of a PECS II to a supraclavicular block for upper arm arteriovenous graft and fistula formation.

 

Methodology   This was a prospective, randomized, double-blind study. Patients with end-stage renal disease aged 20 - 90 years old requiring proximal arm arteriovenous access for surgery involving the axilla were included. Exclusion criteria were regular consumption of opioid or steroids one week prior to surgery; pre-existing upper arm neurological deficits, or previous arteriovenous creation on the same side.

 

Patients were randomized to receive either a supraclavicular brachial plexus block + PECS II block (PECS II group) or a supraclavicular brachial plexus block + sham PECs II (supraclavicular group). The patient, surgeon, anesthesia professional, and data collector were all blinded to group assignment. All blocks were placed with ultrasound guidance. Sedation with midazolam up to 0.02 mg/Kg and/or fentanyl up to 1 µg/Kg was administered as required for patient comfort prior to performance of the blocks.

 

For the supraclavicular block, 20 mL of 0.5% ropivacaine was used. For the PECS II 10 mL of 0.5% ropivacaine was used. For the sham PECS II block everything was the same as a PECS II block except no actual injection occurred. The skin was gently indented with a block needle for 2 minutes to account for the same amount of time to actually perform the block. An opaque dressing was placed over all block sites. Twenty minutes after block placement sensory block in dermatome distributions for the supraclavicular block and PECS II were recorded by a blinded assessor. A satisfactory surgical block was indicated by loss of cold sensation at the C-5 to T-1 dermatomes along with upper arm motor block. For the PECS II the block was considered satisfactory with complete loss of cold sensation to the T-2 and T-3 dermatomes. All surgical procedures were performed 40 minutes after block placement by one of three experienced vascular surgeons who employed the same surgical technique.

 

The primary outcome was the need for intraoperative local anesthetic supplementation (yes or no). Secondary outcomes included the volume of local anesthetic supplementation, need for additional sedation (yes or no), need for additional analgesic (yes or no), total fentanyl administered, pain scores in the PACU, pain scores at 12 h and 24 h; and median time to first rescue postoperative analgesia. Statistical analysis and sample size calculations were appropriate. A P < 0.05 was significant.

 

Result   Eighteen subjects were enrolled in each group after randomization. Baseline characteristics and block characteristics were similar. All brachial plexus blocks were satisfactory with complete sensory and motor block at 20 minutes in both groups. In contrast, only 78% of PECS II blocks were complete.

 

In the supraclavicular group 100% of subjects required intraoperative local anesthetic supplementation compared to only 33% in the PECS II group (P < 0.001). The volume of local anesthetic supplementation was also significantly higher in the supraclavicular block group (15 mL vs. 0 mL, P < 0.001). Significantly more patients in the supraclavicular group required additional sedation compared to the PECS II group (56% vs. 17%, P = 0.015). No significant differences were found in the need for additional analgesic (56% vs. 33%) or total fentanyl received. Postoperative pain scores were similar at all time points. The median time to first rescue analgesic was 3 hours longer in the PECS II group; however, this difference was not significant. No complications were reported from the blocks.

 

Conclusion   A PECS II block was a useful adjunct to a supraclavicular brachial plexus block for upper arm arteriovenous fistula and graft vascular access surgery.

 

Comment

 

This was a very well designed study on the addition of a PECS II block to a supraclavicular brachial plexus block for upper arm arteriovenous graft surgery. I particularly liked how they used a Sham block and assessed block success prior to surgery. This is not often done in regional anesthesia studies.

 

End-stage renal failure patients can be very frail so at my institution we perform these procedures under supraclavicular block. Unfortunately, we have the same problem the investigators described in this study, that the surgeon needs to provide supplemental local anesthesia to block the intercostobrachial nerve. This study demonstrated that a supraclavicular block + PECS II block was successful in providing adequate surgical anesthesia in 78% of patients. Some required supplemental local anesthesia administered intraoperatively. I think these results are promising and I am going to start adding the PECS II block to my toolbox for these patients.

 

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, the Department of Defense, the Uniformed Services University of the Health Sciences, or the United States Government.

 


© Copyright 2019 Anesthesia Abstracts · Volume 13 Number 6, June 20, 2019