Friday, January 30, 2015

Could Spinal be the "Best" Anesthetic for Oocyte Retrieval?

image from national academies press
 Copyright © 2006 Massachusetts Medical Society
In investigating if spinal anesthesia might be the best anestheticand analgesic approach for oocyte retrieval, I found a recent and complete review. This Cochrane review was not designed to make a conclusion regarding spinal anesthesia versus procedural sedation/general anesthesia for oocyte retrieval, but provides a good overview of the limited literature, concluding only that the use of more than one pain relief modality improves patient comfort.  My informal on-line survey of information for patients provided by fertility clinics suggests TIVA incorporating propofol as procedural sedation/general anesthesia is likely the most common method employed for oocyte retrieval in the US.  

Outside of this review, several prospective1,2,3 and retrospective4 studies have found an association between spinal anesthesia and improved outcomes either in the process of anesthesia care3, or in ultimate pregnancy outcomes1,2,4.  As for other regio-local anesthetics, paracervical block has been associated with better pain control during these procedures11 and epidural anesthesia11 and topical EMLA cream12 has been associated with improved pregnancy outcomes. In some of these clinical trials the distinction between procedural sedation and general anesthesia is not clear or inhalational anesthesia was compared to spinal anesthesia.  As has been shown for regional anesthesia and major surgical procedures, the use of spinal anesthesia for oocyte retrieval attenuates hormonal stress responses5.  Several studies have compared the effectiveness of low dose spinals using different doses, baricities, and the addition of fentanyl6-9.  All spinal doses that were studied showed a high success rate with 2-3 hour injection to discharge times.  No comparisons using 2-chloroprocaine were found but doses as low as 3.75 mg of hyperbaric bupivacaine with fentanyl were studied. 

In the absence of a dose ranging study, I suspect that the success of lowering the dose of ultra-low dose spinal anesthesia to speed discharge after oocyte retrieval may be limited y two factors.  One factor is that during oocyte retrieval pain is not limited to a somatic area but is visceral as well.  Another is that good surgical conditions are required to  improve procedural success for this usually bilateral procedure (where success is complete retrieval from two ovaries quickly).  Taken together this may mean that a "walking" or "unilateral" spinal where local anesthetic is administered in extremely small doses or directed away from motor nerves by baricity may not be adequate.   

However, the argument for the utility of spinal anesthesia rests in the idea that spinal anesthesia is well suited to provide the dense analgesia, procedural success, and very best pregnancy outcome important to this population of patients and their reproductive gynecologist.  Though perhaps commonly used, the provision of anxiolysis and unconsciousness-- provided by propofol-- may be of less importance. Could the attenuation of hormonal responses by regional anesthesia during oocyte retrieval be beneficial to pregnancy outcomes in the same way this attenuation is hypothesized to improve outcomes after major cancer and orthopedic surgeries?  While this remains speculation, in nine months time--don't these same patients often choose epidural analgesia for labor or spinal anesthesia for C-section for some of the same patient-centered reasons that spinal anesthesia might make sense here as well?


1. Toon H et al. Is Spinal Anesthesia Preferable to General Anesthesia for Oocyte Retrieval? Anesthesiology 2000 abstract A24. (not published as a full study)
2. Azmude A et al. Pregnancy Outcome Using General Anesthesia Versus Spinal Anesthesia forIn Vitro Fertilization  Anesthesiology and Pain Medicine. 2013 September; 3:239-42.
5. Guasch E et al. [Comparison of 4 anesthetic techniques for in vitro fertilization]. Rev Esp Anestesiol Reanim. 2005;52:9-18. Spanish.
6. Manica VS et al. Anesthesia for in vitro fertilization: a comparison of 1.5% and 5% spinal lidocaine for ultrasonically guided oocyte retrieval. Anesth Analg. 1993;77:453-6.
7. Omi S et al. [Spinal anesthesia with 2% plain lidocaine for ultrasonically guided vaginal oocyte retrieval].  Masui. 1996;45:1507-10. Japanese.
8. Martin R et al. Anesthesia for in vitro fertilization: the addition of fentanyl to 1.5% lidocaine.  Anesth Analg. 1999;88:523-6.
9. Tsen LC et al. Intrathecal low-dose bupivacaine versus lidocaine for in vitro fertilization procedures. Reg Anesth Pain Med. 2001;26:52-6.

Friday, October 31, 2014


I was reminiscing about sitting for the oral boards in anesthesiology (I know: good times...) and how very engaged my junior examiner became when I decided to choose a superficial cervical plexus block for a carotid endarterectomy surgery.  Of course what happens in oral boards land is that-- if your are lucky-- you are told the patient 'refuses' a block.  Else all blocks always fail.  When they do, they fail inconveniently in the midst of the surgery and perhaps without consideration to pharmacology, physiology, or logic.   So that was the scenario I dealt myself that day long ago but I was successful in keeping my fictional patient alive until the knock came to my door.  

Today in the real world, I still believe regional anesthesia is the best way for an anesthesiologist with decent judgment and good skills to avoid trouble and keep his or her patient safe in almost every situation.  So therefore, this post of a regional anesthesia inspired version of the "Keep Calm and Carry On" motivational poster printed by the British government during WWII.  These were only recently made popular, and commercialized by  A brief internet search of the phrase produced the closest match from the National Health Services website which does an admirable job of using the word "calm" several times in connection with regional anesthesia.  Keep calm and do a regional anesthetic.

Thursday, October 9, 2014

Which epidural opioid is the best?

What Epidural Opioid Results in the Best Analgesia Outcomes and Fewest Side Effects after Surgery?: a meta-analysis of randomized controlled trials. 

Review: The authors have performed a meta-analysis resulting in this investigation of 24 publications comparing epidural opioids used by infusion for at least 24 hours of postoperative analgesia . About 2/3's were studies of catheter congruent epidural placement (16/24) and most (?/24) used a local anesthetic agent combined by infusion with the compared opioid. Half the studies used opioid dosing deemed to be equi-analgesic (12/24) and three quarters (18/24) confirmed catheter placement. Two studies were in pediatric patients. The primary conclusion was that morphine was associated with more nausea and pruritis than fentanyl but analgesia measured by VAS was the same. Ten of the studies compared these two particular opioids. Comparative study of hydromorphone was lacking.

Original Abstract:

Epidural opioids are widely used for central neuraxial blockade and postoperative analgesia. However, differences in analgesic efficacy and side effect rates among individual opioids remain controversial.

We conducted a random-effects meta-analysis of randomized controlled trials that compared at least 2 continuous epidural infusions for acute postoperative analgesia over at least 24 hours. Individual study data were weighted by the inverse-variance method. Visual analog scale (VAS) pain scores were the primary outcome. Secondary outcomes included opioid side effects, such as pruritus, postoperative nausea and vomiting (PONV), sedation, hypotension, and respiratory depression.

Nineteen of the 24 trials included compared 2 of the following opioids: morphine, fentanyl, or sufentanil. The total subjects studied were 1513. Pooled analysis by type of surgery showed no clinically significant differences in VAS pain scores at any time after surgery. There were more PONV (OR = 1.91; 95% CI, 1.14-3.18; P = 0.014) and perhaps pruritus (OR = 1.64; 95% CI, 0.98-2.76; P = 0.162) with morphine compared to fentanyl. Total opioid consumption differed only in the trials comparing morphine and fentanyl, where patients in the morphine group required 1.2 mg (of morphine equivalent) less (95% CI, 0.27-2.18). Use of analgesic adjuncts was similar for all but 2 studies.

Analgesic outcome, in terms of VAS pain score, was similar between the epidural opioids studied. These similarities in analgesia may reflect the common practices of concurrently using epidural local anesthetics with the opioids and titrating infusion rates according to a patient's pain status. With respect to side effects, the incidence of PONV and possibly pruritus was higher with morphine compared with fentanyl, despite there being similar total opioid consumption between those groups.

Monday, December 16, 2013

Pain Medicine News - Study Suggests Four Days of Nerve Block No Better Than One Day, After Knee Replacement

Pain Medicine News - Study Suggests Four Days of Nerve Block No Better Than One Day, After Knee Replacement

ISSUE: JUNE 2011 | VOLUME: 9:06

Study Suggests Four Days of Nerve Block No Better Than One Day, After Knee Replacement

by Rosemary Frei, MSc

Patients who have four days of a continuous femoral nerve block (cFNB) after total knee arthroplasty (TKA) do not receive additional benefits compared with those who get one day of cFNB, according to a one-year follow-up study (Reg Anesth Pain Med 2011;36:116-120).
Previously, the authors reached different conclusions—they demonstrated that extending a cFNB from one to four days after TKA provided clear benefits during the infusion, but not after the catheter was removed (Anesth Analg 2009;108:1688-1694). However, they also noted limitations in their ability to generalize these results.
To validate their conclusions, the investigators performed a similar study using a multicenter format, many health care providers and patients on general orthopedic wards. The current study was conducted at five different centers across the United States between April 2007 and August 2009. Subjects undergoing TKA received a single injection of cFNB with ropivacaine 0.2% after surgery up until the next morning. By morning, patients were randomized to continue either perineural ropivacaine (n=28) or normal saline (n=26). Patients, investigators and statisticians were blinded to treatment group.
On postoperative day 4, patients were discharged with a portable infusion pump and catheters were removed. Investigators evaluated pain, stiffness and physical functional disability using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) preoperatively and at seven days, as well as one, two, three, six and 12 months after surgery. Patients were included if they were evaluated for at least four of the six follow-up time points.
The two treatment groups had similar WOMAC scores for the mean area-under-the-curve calculations (P=0.32) and at all individual time points (P>0.05).
The authors concluded that there was “no evidence that extending an overnight cFNB to four days improves (or worsens) subsequent pain, stiffness or physical function after TKA in patients of multiple centers convalescing on general orthopedic wards.”
J.C. Gerancher, MD, professor of anesthesiology and section head, Regional Anesthesia and Acute Pain Management, Wake Forest University Baptist Health, Winston-Salem, N.C., who was not involved in the study, was intrigued by the study findings.
“Our practice is to use femoral catheters for two days after total knee replacement,” he said. “What this study does is give credence to the idea of shortening our duration of infusion and possibly opting for overnight infusions in select patients in the future.”

Patients who received cFNB with ropivacaine 0.2% for one day or four days experienced similar pain, stiffness and functional disability seven days to one year following surgery.

Thursday, December 5, 2013

Floor Plan for a RAAPM (regional anesthesia and acute pain management) area adjacent to the Pre-operative and Intra-operative OR Suites.  The designs features a central and self contained provider area flanked by six procedure bays into which patients enter and leave through exterior folding glass walls.

Slide show posted at Frank L Blum Construction