This post kicks off a new sort of series – quick posts with a range of folks answering questions on how they actually anaesthetise for particular types of cases that turn up during a day at work. First up is inguinal hernia repairs and the contributors are Dr Su May Koh (SMK), Dr Justin Skowno (JS), Dr Sarah Johnston (SJ) and Dr Andrew Weatherall (AW).

We all spend more time doing relatively simple cases than super complex things. So is there any nuance to be had when surgeons are smoothing out those pesky lumps? Well, maybe…

Dividing Them Up

“I like to classify inguinal hernia repairs in paediatrics into two main groups – the very young (neonate to less than 6 months) and the older child.” (SMK)

“Decide where they fall on the continuum between extremely premature infant with apnoeas, to the healthy 5-year-old. The younger they are, the more I tend to place an endotracheal tube with short-acting anaesthetic agents. The older they are, the more I use a standard LMA anaesthetic technique.” (JS)

“The main adjustment I make to technique is all about the risk of apnoeas. So I usually group them in the under 6 months or high apnoea risk group, and the rest.” (AW)

Key Points in Pre-Op Assessment

“Important assessment features include (especially in the very young group):

• Prematurity and gestational age.
• History of apnoeas and risk factors for postoperative apnoeas (see the age thing above, anaemia, apnoea history, lung disease and parental smoking).
• Any significant cardiac or respiratory comorbidities) obviously including sleep apnoeas.

Then it’s gestational age that informs whether I plan to admit for apnoea monitoring for the first night:

• Term babies (born beyond 37 weeks) admit if post-conception age 46 weeks or less.
• Premature babies (32-37 weeks) – admit up to 52 weeks.
• Extreme premature babies (< 32 weeks) – admit up to 60 weeks.

This is also influenced by the other risk factors or social considerations like distance from the hospital to home.” (SMK)

Things I Want to Know from the Surgeon

“There are probably two key things that might influence my decisions during the case:

1. Is there any plan for laparoscopy? – If the operation is planned as laparoscopic or if the plan is for open but a laparoscopic check of the other side at the start, I’ll place an endotracheal tube even in the older kids.
2. Local at the start or at the end? – This is less of an issue with the present surgeons I work with, but I’ve worked with some who feel local anaesthetic messes up their tissue planes for the surgery and they’ll therefore not want local to be in place until the end. This alters my approach to the upfront analgesia.” (AW)

 

What about induction and getting going?

“My technique is pretty straightforward. Gas induction to get started, IV access, muscle relaxant (vecuronium or cisatracurium are handy where I work), ETT.” (SJ).

“For neonates pay attention to the usual issues of a neonatal induction – remember there is not much time until they desaturate, keep them warm and remember to provide glucose somehow.” (JS).

“Most will get an inhalational induction then an IV. If it’s an endotracheal tube I’m reaching for then a dose of muscle relaxant is on the cards. If it’s an LMA that is on the cards then they don’t get that.” (AW)

And those adjustments?

“Where I work a regional only approach is not the option we tend to reach for. So for the kids where I’m prioritising prevention of apnoeas I’ll utilise the shortest acting agents I can find. That means remifentanil as an opioid (I usually just start at 0.5 mcg/kg/min and titrate to haemodynamic parameters and responsiveness). This is pretty much the only time I utilise desflurane and I try to minimise it by using relatively more opioid and encouraging the use of local anaesthetic up front.” (AW).

“For very tiny bubs I might convert to desflurane.” (SJ)

“The younger they are, the more I utilise shorter-acting agents (desflurane and remifentanil). (JS)

Any other bits?

“I keep the CO2 at the lower end of normal as I’d prefer not to have them breathing above the controlled rate. I usually give around 20 mL/kg of isotonic intravenous fluids. Reverse the muscle relaxant and extubate awake.” (SJ)

“I can’t think of many times I’ve regretted waiting a little longer to be sure the neonate is ready for that tube to be removed. I’ve sometimes regretted being eager.” (AW)

What about regionals?

“I always a regional technique regardless. I have done caudal for unilateral ones previously , but currently just do an ilio-inguinal block for unilaterals and a caudal with 1-2mcg/kg clonidine + local for the bilaterals.  I’ve never really understood the point of a block at the end, apart from convenience.” (JS)

“All of the options from spinal alone to a combination of general anaesthetic with caudal or ilii-inguinal (with the ultrasound or by the surgeon) are equally effective but I generally have a chat with the surgeon prior. A spinal is an option for the very young where you’re worried about post-operative apnoeas but requires a willing surgeon who can get the operation done in 40 minutes.” (SMK)

“As I can’t find much clinical benefit in caudals vs other regional techniques, I go with the other regional techniques. The surgeons I work with presently do an excellent job of it and are happy to do that at the start. Otherwise as I have access to ultrasound I’d do it myself.” (AW)

And other analgesia?

“In addition to the block I’d use paracetamol, plus some fentanyl 1-3 mcg/kg in the older kids with LMA in place. For post-operative use the paracetamol continues along with ibuprofen, plus maybe oral oxycodone for the older kids. ” (JS)

“For post-operative analgesia in the little ones I stick with paracetamol. And cuddles. And feeds.” (SJ)

“For post-operative analgesia it’s paracetamol +/- NSAIDs.”

Any other thoughts?

“Particularly with seriously premature infants with active respiratory issues, focus on using ultra-rapid metabolism/elimination drugs. In this day and age, a lot of us have easy access to them so I don’t give a standard dose sevo + opioid anaesthetic to a patient at serious risk of apnoeas. The combination of a regional block and remifetanil with extremely little volatile is a very good option. If you use muscle relaxation, use rocuronium or vecuronium and reverse with sugammadex if you have it. Residula blockade is far more common than we think in paeds.” (JS)

“Even when you use the remifentanil/desflurane combination, those little tykes take a longer time than you might expect to shrug it off.” (AW)

 

So that’s the set? Is it every possible approach. Of course not and we’d love to hear other key points from clever people. But putting it together you could bring it back to this:

• Think about their age group and apnoea risk.
• If you’re thinking apnoea is a risk, consider your options to minimise it and plan your post-op. monitoring.
• GA + administration of local anaesthetic in an effective manner works.
• Simple options for analgesia afterwards are the place to start.

Oh, and as always, give a good anaesthetic.

 

Notes:

That image is from unsplash.com, shared unchanged under Creative Commons and posted by Loic Djim.

 

Now, how about some other reading? There are range of interesting things to poke at when it comes to inguinal hernia stuff and anaesthesia. This list isn’t exhaustive but are worth checking out. Let’s start with the Cochrane review about choice of technique:

Jones LJ, Craven PD, Lakkundi A, Foster JP, Badawi N. Regional (spinal, epidural, caudal) versus general anaesthesia in preterm infants undergoing inguinal herniorrhaphy in early infancy. Cochrane Database of Systematic Reviews. 2015;6:CD003669.

And it turns out there are heaps of things about the many regional options:

Baird R, Guilbault M-P, Tessier R, Ansermino JM. A systematic review and meta-analysis of caudal block versus alternative analgesic strategies for pediatric inguinal hernia repair. J Pediatr Surgery. 2013;48:1077-85.

Klimscha W, Chiari A, Michael-Sauberer A, Wildling E, Lerche A, Lorber C, Brinkmann H, Semsroth M. The Efficacy and Safety of a Clonidine/Bupivacaine Combination in Caudal Blockade for Pediatric Hernia Repair. Anesth. Analg. 1998;86:54-61. 

Did you notice no one mentioned transverses abdomens plane blocks?

Fredrickson MJ, Paine C, Hamill J. Improved analgesia with the ilioinguinal block compared to the transverses abdomens plane block after pediatric inguinal surgery: a prospective randomised trial. Pediatr Anesth. 2010;20:1022-7.

Even though this one says it drops neuroendocrine stress response:

Abu Elyazed MM, Mustafa SF, Abdullah MA, Eid GM. The effect of ultrasound-guided transversus abdominis plane (TAP) block on postoperative analgesia and neuroendocrine stress response in pediatric patients undergoing elective open inguinal hernia repair. Pediatr Anesth. 2016;26;1165-71. 

Kumar KR, Kumar H, Baidya DK, Arora MK. Successful use of spinal anaesthesia for inguinal hernia repair in a child with Hunter syndrome with difficult airway. J Clin Anesth. 2016;30:99-100. 

Oh, and what series of links including regional analgesia would be complete without at least one additive paper?

Lundblad M, Marhofer D, Eksborg S, Lönnqvist P-A. Dexmedetomidine as adjunct to ilioinguinal/iliohypogastric nerve blocks for pediatric inguinal hernia repair: an exploratory randomised controlled trial. Pediatr Anesth. 2016;25:897-905. 

Oh, and do you want a refresher on the ultrasound technique for ilio-inguinal and iliohypogastric nerve blockade?

Wait, did you get all the way to here? Congratulations. Maybe you could really do with a marimba version of classic Super Mario Bros. themes.