ISSN NUMBER: 1938-7172
Issue 12.8 VOLUME 12 | NUMBER 8

Editor:
Michael A. Fiedler, PhD, CRNA

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

Assistant Editor
Jessica Floyd, BS

A Publication of Lifelong Learning, LLC © Copyright 2018

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
Risk factors for severe postpartum hemorrhage after cesarean delivery: case-control studies
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PHARMACOLOGY
The effect of anti-emetic doses of dexamethasone on postoperative blood glucose levels in non-diabetic and diabetic patients: a prospective randomized controlled study
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REGIONAL ANESTHESIA
Total spinal anesthesia failure: have you assessed the sensory anesthesia in sacral dermatomes?
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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 1035464; Expiration Date 10/31/2020.

Obstetric Anesthesia
Risk factors for severe postpartum hemorrhage after cesarean delivery: case-control studies

Anesth Analg 2017;125:523-32

DOI: 10.1213/ANE.0000000000001962

Butwick AJ, Ramachandran B, Hegde P, Riley ET, El-Sayed YY, Nelson LM


Abstract

 

Purpose   The purpose of this study was to identify risk factors for postpartum hemorrhage in parturients who underwent either elective or intrapartum cesarean delivery.

 

Background   Postpartum hemorrhage is a leading cause of morbidity and mortality in pregnant women. In the United States there has been a 160% increase in postpartum hemorrhage related to uterine atony among women who underwent cesarean delivery after induction, and a 130% increase in postpartum hemorrhage in women undergoing noninduced cesarean delivery from1994 to 2006. Severe postpartum hemorrhage is defined as an estimated blood loss (EBL) > 1,500 mL or red blood cell (RBC) transfusion during or within 48 hours of cesarean delivery. A number of risk factors for severe postpartum hemorrhage have been identified which can aid providers to identify “at-risk” women and implement mitigation strategies (e.g., 2nd large bore IV, type and cross PRBCs). Unfortunately, there is conflicting information regarding risk factors and the rate of severe postpartum hemorrhage after cesarean delivery in women who have undergoing elective cesarean delivery or intrapartum cesarean delivery.

 

Methodology   The investigators of this study conducted two case-control studies to identify risk factors for severe postpartum hemorrhage after either elective cesarean delivery or intrapartum cesarean delivery and compare them to a matched control group. Data was collected from medical records in a tertiary obstetric center in the USA between 2002 and 2012. Severe postpartum hemorrhage was defined as EBL > 1500 mL or a red blood cell (RBC) transfusion during or within 48 hours of cesarean delivery.

 

Inclusion criteria for the elective cesarean delivery cohort were scheduled cesarean delivery without induction of labor; cesarean delivery following unsuccessful cephalic version; or cesarean delivery for obstetric or fetal indications; such as preeclampsia or non-reassuring fetal heart rate without labor or induction. For the intrapartum cesarean delivery cohort inclusion criteria were documented evidence of painful regular contractions or induction of labor before cesarean delivery. Women were excluded if they had known coagulopathy (except for HELLP syndrome) or those on anticoagulants. In each cesarean delivery cohort, two controls were randomly selected with the same year of delivery who did not experience postpartum hemorrhage.

 

Result   There were 269 women in the elective cesarean delivery postpartum hemorrhage group and 550 controls. No significant differences were reported in age, weight, parity, or previous history of myomectomy. Women in the elective cesarean delivery postpartum hemorrhage group were significantly more likely to have the following characteristics:

  • hispanic ethnicity (44% vs. 29%, P = 0.001)
  • chronic hypertension (9% vs. 3%, P = 0.002)
  • lower gestational age (37 vs 39 weeks, P < 0.001)
  • first time cesarean delivery (52% vs. 37%)
  • placenta previa (34% vs. 5%, P < 0.001)
  • multiple pregnancies (22% vs. 6%, P < 0.001)
  • gestational diabetes (22% vs. 15%, P = 0.008)
  • preeclampsia (14% vs. 6%, P < 0.001)
  • history of D&C or D&E (24.5% vs., 18%, P = 0.02)
  • lower preoperative Hbg. (11.6 vs. 12.2 g/dL, P < 0.001)
  • general anesthesia (11% vs. 1%, P < 0.001)

(Factors in blue text are shared with the intrapartum cesarean section group. Factors in black text are unique to the elective cesarean delivery group.)

In addition to the significant differences noted above, multivariate regression identified one other risk factor and clarified a second:

  • •predelivery hemoglobin <9.9 g/dL
  • •uterine incision other than transverse

There were 278 women in the intrapartum cesarean delivery and postpartum hemorrhage group along with 572 control patients. Women in the intrapartum cesarean delivery group were no different than controls in weight, parity, rate of chronic hypertension, spontaneous vs induced labor, oxytocin augmentation frequency, cervical dilation before cesarean delivery, or type of incision.

Women in the intrapartum cesarean delivery postpartum hemorrhage group were significantly more likely to have the following characteristics:

  • younger (30 vs. 32 years, P < 0.001)
  • government insurance (49% vs. 37%, P < 0.001)
  • hispanic ethnicity (42% vs. 31.5%, P = 0.01)
  • first cesarean delivery (87% vs. 80%, P = 0.004)
  • multiple pregnancies (13.5% vs. 4.4%, P < 0.001)
  • gestational diabetes (18% vs. 10.5%, P = 0.001)
  • preeclampsia (11.5% vs. 6%, P = 0.004)
  • low predelivery hemoglobin (11.8 vs. 12.3 g/dL, P< 0.001)
  • chorioamnionitis (20% vs. 12%, P = 0.001)
  • magnesium infusion (14% vs. 7%, P = 0.002)
  • general anesthesia (9% vs. 3%, P < 0.001)

(Factors in blue text are shared with the elective cesarean section group. Factors in black text are unique to the intrapartum cesarean delivery group.)

 

The most powerful common risk factors for both elective cesarean delivery and intrapartum cesarean delivery postpartum hemorrhage were: multiple pregnancies, general anesthesia, and pre-delivery anemia. 

 

Conclusion   Women who have an elective cesarean section and those who have an intrapartum cesarean section have many postpartum hemorrhage risk factors in common; most importantly multiple pregnancies, general anesthesia, and pre-delivery anemia. They also have some differences as noted by the factors in black text in the preceding two bullet lists. 

 

Comment

 

Comparing risk factors for severe postpartum hemorrhage after elective or intrapartum cesarean delivery is a like comparing apples to oranges. There will be differences in risk factors because you are comparing a uterus that has been contracting and /or receiving uterotonics and been in labor to one that has not. However, in this study there were some common risk factors found, which make sense: multiple pregnancies, administration of general anesthesia, and anemia. Anemic patients are going to be more likely to need a transfusion, especially if they fall below 9 g/dL. Multiple pregnancies put added stress on the uterus and may contribute to atony. General anesthesia causes smooth muscle relaxation in the uterus and contributes to atony and may result in increased bleeding. Combined spinal / epidural anesthesia is unlikely a risk factor for severe postpartum hemorrhage after elective cesarean delivery, but rather looked like one because anesthesia providers probably administered a CSE because they anticipated the surgery would take longer in women who may have had other risk factors for postpartum hemorrhage, such as multiple pregnancies. The other risk factors identified may be related to lower socioeconomic status (Hispanic ethnicity, government insurance) or are known risk factors for postpartum hemorrhage; chorioamnionitis, previous D&C/D&E, and placenta previa.

So how do these results inform our practice? I think the results help to highlight the importance of recognizing women at risk for severe postpartum hemorrhage and to be prepared. You should ensure your facility has a postpartum hemorrhage protocol and it should be drilled regularly and reviewed by staff every time you have a patient at risk for postpartum hemorrhage. Find out what your blood bank capabilities are. Do you have tranexamic acid? Does your staff know how to use a rapid infuser? Ask yourself, “Who would I call if I needed an extra pair of hands?” These are just a few things to consider.

I encourage readers to check out the American College of Obstetricians and Gynecologists postpartum hemorrhage toolkit at https://www.acog.org/About-ACOG/ACOG-Districts/District-II/SMI-OB-Hemorrhage .

 

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 2018 Anesthesia Abstracts · Volume 12 Number 8, April 3, 2018




Pharmacology
The effect of anti-emetic doses of dexamethasone on postoperative blood glucose levels in non-diabetic and diabetic patients: a prospective randomized controlled study

Anaesthesia 2016;71:1037-43

DOI: 10.1111/anae.13544

Tien M, Dhakal GI, White WD, Olufolabi AJ, Fink R, Mishriky BM, Lacassie HJ, Habib AS


Abstract

 

Purpose   The purpose of this study was to compare blood glucose levels in diabetics and non-diabetics receiving postoperative nausea and vomiting (PONV) prophylaxis with 8 mg dexamethasone or 4 mg ondansetron.

 

Background   Dexamethasone is commonly administered to prevent PONV. Some studies have found it causes postoperative hyperglycemia; however, few studies have examined the effects of dexamethasone on blood sugars in patients with diabetes. The investigators hypothesized there would be a greater rise in blood glucose levels with administration of 8 mg dexamethasone compared to ondansetron in both diabetics and non-diabetics.

 

Methodology   This was a prospective, randomized study of type-2 diabetes and non-diabetes patients undergoing elective surgery. Patients with preoperative glucose levels > 200 mg/dL and those taking steroids were excluded. Patients were randomized to receive either 8 mg dexamethasone prior to induction or 4 mg ondansetron towards the end of surgery. Randomization was stratified by diabetes status to insure that an equal number of diabetic and non-diabetic patients received both treatments. Patients with a history of PONV received promethazine 12.5 mg on induction and metoclopramide 10 mg if needed in the recovery room. Diabetes patients did not take their anti-diabetes medications on the day of surgery. Anesthetic technique was standardized. A baseline venous blood glucose level was drawn in the preoperative holding area, and then at 2h, 4h, and 24h following induction of anesthesia. Diabetes patients had periodic finger stick blood sugar levels drawn and a sliding scale used for administration of insulin.

 

Result   There were N = 85 patients randomized to one of four groups:

  • diabetes-dexamethasone n = 20
  • diabetes-ondansetron n = 24
  • no diabetes-dexamethasone n = 20
  • no diabetes-ondansetron n = 21

Baseline demographics, surgery procedure type, and clinical characteristics were similar. Baseline blood glucose levels were similar. Blood sugar levels increased in all groups during surgery compared to baseline. Blood sugar levels in No diabetes-Dex patients were significantly higher at 4h vs. No diabetes-Ond group (P = 0.02) but the increase was of questionable clinical significance and still well below 180 mg/dL. Diabetes-Dex patients had significantly higher blood sugar levels at 24h than diabetes-Ond patients, on average about 180 mg/dL (P = 0.05; Figure 1). Maximum blood glucose levels at any time within the 24h data collection period were significantly higher in No diabetes-Dex vs. No diabetes-Ond patients, 164 mg/dL vs. 140 mg/dL (P = 0.04; Figure 2). Nevertheless, the difference of 24 mg/dL was relatively small. The percent of patients who had a blood sugar level ≥ 180 mg/dL at any time during the 24 hours was highest in the diabetes-Dex group at about 95% of patients(P < 0.01 compared to diabetes-Ond). The diabetes-Ond patients were next with 50% reaching a maximum blood sugar level of 180 mg/dL (Figure 3).

 

Figure 1. Blood Glucose over Time

Notes: 10 mmol/L = 180 mg/dL. 6 mmol/L = 108 mg/dL. This data measured at the time points indicated.

 

Figure 2. 24 Hour Maximum Blood Glucose

Notes: 15 mmol/L = 270 mg/dL. 10 mmol/L = 180 mg/dL. 5 mmol/L = 90 mg/dL. This data reflects the maximum blood glucose level for each patient at any time during the 24 hours.

 

Figure 3. % with Maximum Glucose >180 mg/dL

 

Multivariate analysis demonstrated that patients who received dexamethasone had a significantly larger increase in maximum 24-hour blood glucose levels (P < 0.01) after adjusting for diabetes status (P = 0.01), baseline blood glucose level (P < 0.01), insulin dose (P < 0.01), promethazine use (P = NS), surgery type (P = NS), and surgery duration (P = NS). The predicted maximum increase in 24-hour postoperative blood glucose was 34 mg/dL higher in patients who received dexamethasone (95% CI, 18 to 52 mg/dL).

 

Conclusion   Dexamethasone increases postoperative blood glucose levels in diabetics and non-diabetics. In this study 95% of diabetic patients who received dexamethasone had a maximum blood glucose > 180 mg/dL. Providers should be cautious in administering 8 mg dexamethasone to diabetic patients.

 

Comment

 

Many anesthesia providers routinely administer prophylactic anti-emetics (dexamethasone and ondansetron) to all patients, regardless of PONV risk status. While the medications are safe and cost-effective compared to delayed discharge secondary to PONV, anesthesia providers might want to avoid administering dexamethasone to diabetics. If you do, make sure you tell your nurses and patients to monitor postoperative blood glucose levels closely. You might want to order sliding scale insulin and/or tell your patients to resume taking their anti-diabetic medications once they are able to eat.

 

Dennis Spence, PhD, CRNA


The original article abstracted here is available free full text at the following url: https://onlinelibrary.wiley.com/doi/epdf/10.1111/anae.13544

 

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 2018 Anesthesia Abstracts · Volume 12 Number 8, April 3, 2018




Regional Anesthesia
Total spinal anesthesia failure: have you assessed the sensory anesthesia in sacral dermatomes?

Anesth Analg 2017;124:1674–7

DOI: 10.1213/ANE.0000000000001966

de Sá Oliveira RR, Módolo MP, Mizubuti GB, Ho AMH, de Barros GAM, Muniz da Silva L, Braz LG, Módolo NSP, Day AG, Phelan R, Navarro E Lima LH, Ganem EM


Abstract

 

Purpose   The purpose of this study was to report the incidence of spinal anesthesia failure, review risk factors for failure, and describe the role of evaluating sacral dermatome levels when evaluating a failed spinal.

 

Background   There are a variety of reasons for a failed or partial spinal anesthetic. They include technical failure, underdosing of local anesthetic, positioning, inexperience, errors in preparation and injection, and anatomy. Repeating a spinal after a failed attempt may result in a high level, total spinal, and/or neurotoxicity. To avoid neurotoxicity it is recommended that anesthesia providers evaluate the sacral dermatome spread of a failed or partial spinal anesthetic. However, many providers do not do this.

 

Methodology   This was a prospective observational cohort study of 3,111 consecutive patients undergoing spinal anesthesia at a Brazilian teaching hospital between December 2008 and January 2011. Cases included patients undergoing surgical or obstetric surgical procedures. Exclusion criteria included contraindications to spinal anesthesia or the inability to insert the needle into the subarachnoid space. The primary outcome was the incidence of spinal anesthesia failure. Secondary outcomes included partial failures restricted to sacral dermatomes and risk factors for failed spinal anesthesia.

 

Patients received either plain or hyperbaric 0.5% bupivacaine, with a dose appropriate for the surgical procedure. Admixture agents and dose administered were at the discretion of the anesthesia provider. Spinal anesthesia failure was defined as absent or inadequate sensory and/or motor block 15 minutes after local anesthetic injection. At 15 minutes, motor block (modified Bromage scale) and sensory block (response to cold and pinprick) at the thoracolumbar level were assessed and recorded. Failures were categorized as partial or total. Partial failure consisted of inadequate cephalad spread, unilateral block, “patchy” block, or inadequate duration, resulting in incomplete anesthesia. Total failure consisted of complete absence of anesthesia despite an adequate dose of local anesthetic. If total spinal failure was determined, an evaluation of the sacral sensory dermatomes was performed. Total failed spinals with no evidence of sacral spread received a repeat “full-dose” of bupivacaine. Failed spinals with a partial block received a partial dose not to exceed a total of 20 mg bupivacaine or they received general anesthesia.

 

Result   There were 3,111 patients included in the analysis. There were 880 (28%) obstetric patients and 2,231 (72%) non-obstetric patients. Of those, 91% received hyperbaric bupivacaine and 98% of spinals were placed in the sitting position. The most common spinal needle was a Quinke (99%), with most using a 25 gauge spinal needle (82%). In 91% spinals were placed midline while 9% were paramedian; 3% were placed at L2-3, 55% at L3-4, and 42% at L4-5. A little less than half of all spinals were placed by an anesthesia trainee with less than 1-year experience. There were 1% of spinals where cerebral spinal fluid (CSF) could not be aspirated, 1.5% with abnormal CSF flow, and 1.4% with evidence of blood in the hub before local anesthetic injection.

 

The incidence of partial or total failed spinal anesthesia was 6% (n = 194; Figures 1 and 2). Of the 72 presumed total failed spinals, 44% (32) had evidence of sacral dermatome spread. Of all 194 spinal failures, 8% (15) had previously experienced a partial or total spinal failure. Spinal anesthetics administered by an experienced trainee (>1 year experience) had a 33% lower rate of failed spinal anesthesia (P = 0.01). Dural puncture at the L4-5 interspace increased the risk of a failed spinal by 59% (RR = 1.59, P = 0.001). The strongest risk factors for failed spinal anesthesia in order of importance were:

  • inability to aspirate CSF (RR =3.84, P <0.001)
  • blood in the needle hub (RR = 3.32, P = 0.001)
  • abnormal CSF flow (RR = 2.81, P = 0.005)

Figure 1. Spinal Anesthesia Outcome (N = 3,111)

 

Figure 2. Failed Spinal Outcomes (N = 194)

 

Conclusion   Anesthesia providers should consider evaluating sacral dermatome spread when suspecting a spinal anesthetic failure.

 

Comment

 

Spinal anesthesia is one of the most reliable anesthetics. Assuming no technical errors or under dosing of local anesthetic, it works virtually every time. However, when there is a partial or total failure, one has to decide should I:

1. reattempt the spinal with a full or partial dose

2. place an epidural

3. administer general anesthesia

The decision is based on the clinical situation (elective procedure or emergency).

 

Deciding how much local anesthetic to give in a repeat dose is always a challenge, especially in a parturient undergoing cesarean delivery. If I have a partial block, I might sit the patient up and place an epidural and titrate to an adequate level. If I have no discernible level, then I might consider repeating a full local anesthetic dose, for example 12 mg of 0.75% bupivacaine. I have never checked the sacral dermatomes with a partial or failed spinal anesthetic, or considered limiting my dose of bupivacaine to 20 mg (although I usually place an epidural if I have a partial spinal level), but after reading this article I might consider adding this to technique to my “toolbox.”

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 2018 Anesthesia Abstracts · Volume 12 Number 8, April 3, 2018