Life after Infant Botulism

The large gaps in posting on this blog illustrate beautifully the fact

that despite Infant Botulism putting our life on hold for a period of time,

 life does indeed go on.

 

Baby T (now best known as Big boy T) is now 2 years and a few months

post-diagnosis and treatment.

He is fabulous.

 

 

He's tenacious, vivacious and bursting with energy.

Most parents I discuss IB with are concerned about future health problems which may result from their child having once recovered from IB.

So far we've encountered no issues (knock on wood).

 

 

We became captured by this little-big guy long before

Infant Botulism made him one in a million.

 

I often hear from families who are grateful to see how well Baby T is doing.

Big boy T is here to show you that he is absolutely fine.
And your baby will be too.

I am truly thankful for having the opportunity to share many botulism recovery stories so that other families can have a rough idea of what to expect.

Expect many extremes..sadness, joy, defeat and triumph.
And be grateful for a full recovery.
Because recover they do.

 

 

 

 

 

 

 

Baby T's Story, Chapter 20- A year after Infant Botulism

Over a year ago Baby T’s journey with Infant Botulism began.
IB Dad and I often remark how it feels even further away now
because our baby has evolved into a busy boy-toddler.
 

                  

 

 

 The more he blossoms, the further away the memory of his battle with IB becomes.

I try not to dwell in the worry of being a parent as it’s very easy to become consumed with the past.

I’ve found that many parents have their own emotional challenges to overcome
after witnessing what IB does to their child.

 

 

Knocked down temporarily
 

When your child is in the thick of it, you feel as though things will never get back to normal.

The worry that your baby will be forever changed or effected negatively it tangible and hard to shake. 
But, it does get better. Babies are amazing and resilient.


Being a toddler is exhausting !

 IB is awful, but a year later our perspective is more of luck and gratitude.

Luck being, IB is treatable, and the survival rate is high.

Gratitude for BabyBIG, and the support of the IBTPP

as well as the many friends and family we have who supported us and continue to do so.

 

 

Our infant son, Baby T, became critically ill at 7 months old.

A year later he’s a walking, talking, falling, eating, nursing, on the go,

inquisitive, smart, loving, completely normal and stubborn toddler. 

 

 

 

He has no idea what happened a year ago,

he’s too busy being focused on the joys of today.

Baby T's Story, Chapter 19- Recovery Pt. 3-Six months later...

8/14/12

What has Baby T been up to?

ALOT actually....

The big guy turned one last month.

We had a low-key celebration due to his tendency to get a bit antsy around big crowds.

I included honey sticks in the favor bags for the young guests (all were over 1 yr of course).

He received (and tasted) a birthday card from the

Infant Botulism Treatment and Prevention Program (thanks IBTPP Staff)

A rare (and tasty) card indeed!

Next week will mark the six month anniversary of Baby T being diagnosed with infant botulism.

IB Dad and I often remark on how "long ago" T's hospitalization feels.

Since our last update in April, there have only been 6 appointments!

Less appointments mean more time to enjoy summer.

Hanging out with sister

We took a family vacation, Baby T's first long car trip.



"Point and wait for explanation"

We visited the beach and he got sand in every nook and cranny.

Our summer has included a myriad of good times

though we're mainly celebrating our excellent health!

Baby T is morphing into a boy-toddler right before our eyes.

He is more determined to get into mischief and

is NOT easily distracted/redirected when he has a goal in mind.

He can go from cuddling to yanking our hair/pinching 

then back to cuddling; all within one breath.

We love how mischievous he has become.

Ironically, I ran into the ER dr who was stumped by T when we initially brought him in. He was happy to see our guy doing so well. He confessed that he was keeping tabs on him throughout his hospitalization and exclaimed how  Baby T's case has since been discussed often within the medical community.  He clarified that he wasn't pondering discharging us (as I had previously thought) but was genuinely stumped as to what was occurring with Baby T (but was certain it was not looking very good).  He expressed gratitude for the PICU staff who had an inkling that they were dealing with Infant Botulism in this instance.

Baby T saw his neurologist in May and she was impressed with his progress and doesn't need to see him again until he is walking (or 18 months, whichever comes first).

At his 1 year check up, T's pediatrician was happy to see how well he has recovered.

"I thought these bracelets were a thing of the past! Get it OFF"

We troubleshooted some ways to help T's constipation (which can last for a full year after diagnosis).

His weight gain stabilized after some minor losses

(as his pediatrician so eloquently stated, "he is no wilting flower")

Baby T continues to nurse frequently and dabbles in solid foods

but doesn't seem terribly interested in eating solids very often.

 Today Baby T stunned his physical therapist!

Not only is he crawling like a champ now...

He is on the VERGE of walking!!



"Look out world, here I come!"

He really turned on the charm for PT and while she sure does

love to see Baby T, she doesn't need to see us for 6 weeks!

There are times when I wrestle emotionally with what happened to him.

In communicating with other 'IB Moms' I've often been warned

of feeling these emotional aftershocks for some time.

The hand sanitizer at his dr's office takes me back to the days where

I was required to wash my hands even if just to caress his cheek.

I donated the frozen breastmilk that was pumped during his hospitalization

and while doing an inventory of the stash, certain dates took me back to the PICU pump room.

The sessions where: stress would zap my supply, in the early morning where I'd be exhausted but then shocked into reality and have trouble leaving his side, and when I would rush through in order to return to him as the paralysis wore off and his smiles returned.

I'm so grateful that he won't remember everything that he went through.

His bright eyes have always seemed to be reassuring me that everything is going to be just fine.

It feels so good to move beyond his first year.

And what an amazing year it was.

 

Click to read the latest update on Baby T, one year after IB.



Baby T's Story, Chapter 18- Recovery Pt. 2, free from tubes

3/18/12-4/30/12

Baby T amazes us throughout his recovery!

After pulling his NG tube, his weight was monitored

but luckily we did not need to have the NG reinserted.

At a month and a half after discharge we've

had a total of 13 appointments.

Five appointments are scheduled

within the next month.

T see's a neurologist, Occupational Therapist,

Physical Therapist and his regular Pediatrician.

At 9.5 months:

He is nursing well and is making strides

in his ability to eat solids.

He is sitting again, and has

now mastered rolling.

Last week we got clearance to take Baby T out

though the pediatrician encouraged us

to still exercise caution.

Those who know Baby T well comment

on how he doesn't look like

he was ever sick.

He's as smiley and silly as before.

We're waiting for his care team to deem him "fully recovered".

Until then we're enjoying introducing Baby T

to all the firsts that babies his age enjoy.

He experienced his first "swim" in a pool.

He rode on a cable car and a carousel.

He tasted the first strawberries of the season.

And he was finally reunited with his favorite pastime,

the baby swing.

My breath still catches when I consider

how ill he was and how terrifying

some of those days were.

We're so very thankful to everyone

who has helped us get through what

has been the roughest part of our lives.

If your baby has IB we sincerely wish that

Baby T's story gives you

hope for recovery.

We hope that eventually you find peace.

Thank you.

Click to continue reading, Baby T's story Chapter 19

Baby T's Story, Chapter 17- Recovery Pt. 1

3/9/12-3/17/12

I just about jump out of my skin when the NG pump

alarm sounds in the middle of the night.

The only alarm in my home that would be that loud

would be the smoke/carbon monoxide detector.

I refill the bag which feeds the NG pump

as my heartbeat steadily returns to a normal pace.

Baby T sleeps through the whole process.

I crawl back into bed next to him,

cuddle him thoroughly

then return to slumberland.

Being home is freedom.

Except for the mass amount of appointments we've accumulated.

Baby T's first appointment is with his regular pediatrician,

the day after his hospital discharge.

We're his second confirmed case of botulism in

his ten (plus) year span as a pediatrician.

He's been monitoring Baby T's case closely

and we discuss the plan in moving forward.

His weight will need to be monitored,

Baby T lost about a pound in the hospital.

We're also not to take T around any

younger children or public spaces.

The flu & RSV are spreading like wildfire

and with Baby T in his vulnerable state,

avoiding exposure is recommended.

His NG night feeds should continue

but may need to be adjusted based on his weight gain.

The pediatrician asks us a few questions,
answers ours, and then we're on our way.

Our first few weeks home are spent decompressing.
Baby T spends alot of time nursing as he is weak.
At night he has a little trouble going
to sleep and will only settle when
he lays down on me.
We ease back into our lives
but we continue to revolve around Baby T.





His weight fluctuates so we sometimes have to visit
the doctor two times in one week.
Being confined to our home is the most
difficult order to follow.
Luckily, our family is available to assist us.

A neurologist appointment the week after discharge
brings us back to the hospital we'd become so familiar with.
It is odd to walk past it with Baby T
snuggled against me in the ergo carrier.


Neurology is happy with Baby T's progress and
plan to see him again in two months.



On his ninth day home (St. Patrick's day),
Baby T pulls out his NG tube.
Finally, he is free from tubes.

Click to continue reading Baby T's Story, Chapter 18

Baby T's Story, Chapter 16- Home

Thursday 3/8/12

Baby T and I experience another restless night in peds.

Our lack of rest solidifies my desire to get him discharged.

I truly feel that he is now ready to recover at home.

The pediatricians visit early and discuss that Baby T seems ready to go home

and likely can be discharged without the NG tube.

I'm so very excited about their confidence in T being ready

and even more excited about leaving the NG tube behind.

Neurology comes and feels that the NG tube is necessary for discharge.

At this point I've already called my family to let them know we

should be returning home later that day.

I'm confused by the differing opinions between the staff.

During rounds I practically plead that they discharge us.

They debate whether his NG tube is necessary.

OT is requested to re-assess his swallow.

The peds concur that discharging with the NG would be

best just to make sure that he continues to gain weight.

The only problem is that the NG training and equipment take a day to order.

This would delay our discharge until tomorrow.

IB Dad and my parents arrive and are confused by the change of plans.

I'm upset since exhaustion is now really catching up with me

and I feel that he is so very close to coming home.

Our bags are packed.

I try to chin up and convince myself that one more

day wouldn't be terrible.

But it is.

We need to go home.

Luckily, a sympathetic nurse hears me (and my family) out.

It turns out that her daughter was hospitalized as an infant and

discharged with an NG tube.

The nurse understood our urgency to return home.

She put rush orders in on our equipment and facilitated

a quick NG feed training session.

I requested to see the pediatrician once more and

we went over the discharge orders.

Baby T is to get weight checks weekly,

will have Occupational and Physical Therapy appointments.

And will need a pediatrician appointment the next day.

He will get 800 ml of breastmilk in the NG tube over

an 8 hour period at night.

Otherwise he can breastfeed on demand and

be supplemented with baby food.

Many of the PICU staff hear about our imminent discharge and make their way

over to peds to say good-bye to Baby T.

Last nap in the hospital

The equipment arrives.

Papers are signed.

The IV is pulled.
We load up all of the frozen breastmilk (over 100 oz)
which requires a cooler for transport.

We dress Baby T for the first time in over 2 weeks.
Soon we are discharged.

Walking out with him feels surreal.

I walk him down the corridors that I've previously

walked in such a sad state.

We pass the parent room where I've slept

many nights during our stay.

We take the common elevator

and Baby T catches the curiosity of many

since he still has his NG tube.

Every step we take puts more distance between him

and the machines, needles, dressings, medications, health care workers,

cribs, tests, lights and tubes.

Soon we settle him into his car-seat.

We put miles between us and the hospital.

Ready to go home!

I cannot stop myself from repeatedly commenting to IB Dad about how
strange it feels to be finally leaving the hospital with Baby T.

We arrive home and are greeted by our girls and IB Dad's mother.

Baby T lights up when he sees his sisters

but he's easily overwhelmed with their exuberance.

We quickly settle into our home once more.

IB Dad and I set up the equipment for the

overnight NG feeds.

While we're waiting for the breastmilk to thaw,

we talk and marvel at our sleeping Baby T...

and end up falling asleep together.

We wake up a couple of hours later laughing at

how tired we must have been in order to fall

asleep in mid-conversation. 

The milk is thawed so we

set up Baby T's first NG feed at home.

Being reunited with my family,

Baby T sleeping at my side,

in my own bed,

in our home.

We are

finally,

unbelievably

 home.


Click to continue reading Baby T's Story, Chapter 17

Baby T's Story, Chapter 15- Breastfeeding reunion

Wednesday 3/7/12

Baby T and I are adjusting to life in Peds.

It's so nice to be going from him being so intensely monitored to nearly nothing.

After a weight check in the morning they leave his leads off so I can pick him up whenever I wish.

It's much easier to pick him up with only an NG tube to negotiate.

It is relieving to be able to comfort him in my arms.

I meet Baby T's new care team in the morning.

Rounds are done in the hallway as the room is too small to hold everyone.

I get the news that RT will remove his nasal canula

and that I can breastfeed my baby once more!!

My excitement is contagious.

When rounds are over I burst back into the room, and skip over to my baby's bed.

I encounter his smiles and tell him that he gets to breastfeed again.

Then I realize that he may not remember how to breastfeed...

One of my favorite RT's comes by to remove his nasal canula.

She's thrilled by his progress and enjoys freeing him from another tube.

I request the nurse to stop his NG feed.

I decide to nurse Baby T before IB Dad arrives so that he won't be so distracted.

Our nursing reunion is far from the glowing reunion I had envisioned.

He bites and can't seem to get a good latch.

His suck is weak and he gags a bit which causes me alot of anxiety.

He improves quickly though.

Reuniting with my nursling is bliss.

OT and a pediatrician visit during our nursing session and feel that he is doing well.

OT explains that he may take a bit longer negotiating breastfeeding

since milk/thinner fluids take more muscle coordination than solids.

They both feel that he may not need his NG tube upon discharge.

IB Dad arrives and we decide to celebrate Baby T's progress by eating take-out greek food.

It feels good to enjoy the strides he is making.

We feel confident that he'll be coming home soon.

A dr. feels that discharging T soon would be best since

the peds floor is rampant with RSV patients.

Baby T likely isn't strong enough to handle

any kind of respiratory problem.

Discharge.

It sounds too good to be true!

We continue to work on breastfeeding though Baby T is given

some breastmilk through the NG tube at night.

Click to Continue Reading Baby T's Story, Chapter 16

Baby T's Story, Chapter 14- Goodbye PICU!

Tuesday 3/6/12

A restless night is met with even better news in the morning. 

Baby T is moved from a high flow canula to a regular one.

He is breathing well so less assistance is expected.

The footwork to move us out of the PICU is underway.

His NJ tube is pulled back to become an NG tube.

His compromised airway made the NJ (goes further into his intestine)

necessary but now it was time to see if he could handle the NG.

An occupational therapist is added to T's scheduled visitors.

She evaluates his swallow as he takes some solid food.

He does well so she says we can work on breastfeeding soon.

This news couldn't be more welcome.

Pumping, while completely necessary for maintaining my supply, is WORK.

I've gained a new sympathy for moms who need to maintain a long-term relationship with a pump.

Baby T also gets his Arterial line removed.
This free's up his left arm which has been
tied up by lines ever since we arrived.
Losing this line means stability,
they no longer need to do blood labs!

Soon, we get approval to leave the PICU.

After 2 long weeks Baby T is well enough to move to peds (literally across the hall).

The massive amount of stuff we've accumulated is packed up.

I miss the nurses and doctors but know that I'll never ever wish to return there.

That morning we overheard a mother being told that her child's "options" are now severely limited.

I'm reminded once more of how lucky we are through this entire ordeal.

Peds is small.

Our space is about 25 % smaller and we're wedged between two other patients.

No security is necessary to enter our room which means our neighbors

can invite their entire extended families into the room (and they do!).

The nurses & RT's only need to visit every 4 hours now.  

Baby T is in good spirits and handling his NG transition well.

They try bolus feeds to see if he tolerates a larger amount in a shorter timeframe and he does great.

I'm anxious for rounds the next morning as one of our neighbors (a 3 yr old) has white-coat syndrome and screams through her CPT, waking Baby T & I every few hours through the night. 


Click to continue reading Baby T's Story, Chapter 15

Baby T's Story, Chapter 13- Extubated for good

Monday 3/5/12

Baby T before extubation #2

Baby T has a decent night but loses one of his IVs so will need it replaced at some point.

Rounds are made and he is cleared to be extubated.

IB Dad & I are excited but our experience from last week forces us into "wait and see" mode.

His IV is replaced and miraculously only takes an hour.

Soon we're told it's time to go while they extubate.

We give him lots of kisses and encourage him to be strong.

The procedure is quick and we walk in and immediately see our happy little guy beaming back at us. Seeing his full smile without the vent tube melts our hearts!

What's the big deal guys?

Giving daddy some big smiles

He doesn't whimper or seem to be struggling.

He is so happy!

I quickly go pump while IB Dad & the nurse give him a bath.

Very soon we each get to hold him

(while we joke with staff about having to fight over who gets to hold him first).

It is pure bliss!

As the hours pass we get our usual visitors (peds, neurology, physical therapy, etc)

and they are all overjoyed to see him off of the vent.

The nurses change shifts and a new crew is thrilled to see him thriving.

I'm so very proud of my strong chubby guy.

Our excitement is muted in the evening as our neighbor (a 5 month old) gets intubated.

Usually they have everyone on the floor leave but no one asked us to leave

 so we stayed and saw nothing but heard everything :(.

It breaks our hearts to hear another baby get that procedure done, and reminds us of how unpredictable this whole ordeal has been.

We squeeze Baby T alot and hold him tighter.

I get to sleep bedside again which is great but T is too excited

and doesn't sleep well that night (his glowing toe was quite distracting!!).

Baby T hypnotized by the magical glowing toe

I don't know at that point, but this is our last night in the PICU.

No wonder Baby T wouldn't settle down!



Click to continue reading Baby T's Story, Chapter 14

Baby T's Story, Chapter 12- Mustache & CPAP Sprints

Saturday- Sunday, 3/3/12-3/4/12

The last of the long term patients has left.

We have now been in this PICU longer than any other patient. I dream of the day when we can leave.

Everyday we see the excited patient families leave along with the anxious families

who are new, tender and quite traumatized.

The PICU itself is bi-polar; Calm one minute and then manic the next.

We’re humbled by the conversations that we have with other families

and realize despite the ongoing fear, we are lucky.

Many of the admits have a long history of PICU visits and other hospitalizations

and will continue to be frequent inhabitants.

Many of them have terminal illnesses or have been sick for the majority of their lives.

Our stop here is temporary and YES it is awful,

but it could be so much worse...

Baby T is gaining strength once more. It is nice to see his feistyness return.

We add a mustache to his vent tape for morning rounds suggesting

that T has been here so long that he’s growing facial hair. The staff enjoyed the laugh.

His lung continues to open so CPAP sprints are planned for the

entire day Sunday with the goal of extubating again on Monday.

This time they want to test his strength by decreasing the support in "sprints"

and monitoring his reaction.

He does well on his sprints so the NPO orders are in.

IB Dad & I anxiously await another extubation,

set for 3/5.

This time feels different.

We really feel like he is ready.

Click to continue reading Baby T's Story, Chapter 13

Baby T's Story, Chapter 11- Rest

Thursday-Friday 3/1/12-3/2/12

Baby T is exhausted and takes a couple of days to recuperate.

All of the nurses who come onto their shift and see him re-intubated are sad to see him back on the vent.
They take time to speak with us about what happened and let us know that they are cheering him on.

 Initially the dr.’s are worried about needing to refer to a pulmonary specialist who can

send a scope down and potentially remove mucous from the collapsed lung.

The Dr.'s warn that the lung remaining closed puts Baby T at risk for infection. 

The vigorous CPT and respiratory treatments do their job and x-rays reveal that

the lung is opening slowly.

The dr.’s continue to warn us that the recovery time may be weeks to months.

We stay by Baby T's side and wait for him to get stronger.

T slowly regains his strength on the vent and we see more of his smiles.

His resiliance and positivity are contageous

.

After all, if he can smile after all he has been through.......

.....how can we not?

We smile for him and he lights up
even more as if he's saying

"See mom? I'm alright.
Don't be scared, i'm not."

Click to continue Reading Baby T's Story, Chapter 12

Baby T's Story, Chapter 10- Lung Collapse

Wednesday 2/29/12

After an uneventful night, all seems well. 

Everyone encourages us that the likelihood of Baby T being

intubated decreases as more time passes. 

I leave for home in the morning while IB Dad stays with Baby T.

As I am getting our middle child settled for her nap,

I text IB Dad to check and see how T is doing.

IB Dad calls me back immediately and is distraught. 

He explains that Baby T was doing fine, but then had started to destat
(his respiratory rate/oxygen monitors were indicating that he was heading for respiratory failure).

Doctors and nurses rushed in and they worked to get T back into normal range.

They couldn’t so he is being intubated once more. 

I rush back to the hospital.

When later getting the details of this event IB Dad described how scary it was to see Baby T in good shape one minute but then all of a sudden he looked "out of it".

His eyes began rolling around and his palor totally changed.

His second intubation wasn’t as smooth.

I join IB Dad in the hallway outside and we wait a very long time. 

When I see Baby T again he has another tube in the other nostril

which is draining his stomach contents. He has another machine to add breathing assistance

and more closely monitor his vent settings.

Seeing him back on the vent is terrible.

We thought that his progress was a one way street,

but he seemed to have U-turned and retraced his steps.

An xray revealed the cause.

His right lung has collapsed.

RT’s begin vigorous CPT and breathing treatments to try and open it.

 Xrays become a regular part of his schedule now.

No one was talking much about his prognosis so we were very anxious the rest of the evening

until a pediatrician came by and discussed with us what they believed had happened.

Basically he was too weak and they extubated too soon.

The doctor’s had felt he was ready when he really was not. 

Breathing took too much effort thus the decreased movement in his limbs.

His full recovery is still expected and isn't necessarily in jeopardy

but he now had more hurdles to cross.

IB Dad and I are devestated but do try to remain hopeful.

Baby T continues to have periods of struggle through the night as adjustments to the vent are made.

Click to continue reading Baby T's Story, Chapter 11

Baby T's Story, Chapter 9- CPAP Struggles

Tuesday 2/28/12

Baby T is still struggling on the CPAP but the blood gases are returning

within the normal realm so the day continues.

The dr’s are wary of him needing to be intubated emergently, and wish to avoid it.

We get to hold him more.

He is difficult to hold with the various tubes and his complete lack of tone

(imagine holding a 25 lb newborn!) but it feels good to feel his weight again.

The CPAP settings have been adjusted so the machine isn't constantly going off.

We encourage him to continue being a strong little fighter.

He is very tired so PT is quick.

Neurology comes by and they feel he is struggling off of the ventilator

but agree with the pediatrician's "wait and see" approach.

In the evening they are able to resume NJ feeds.

At this point he has been only receiving IV fluids for nutrition for 24 hours.

I'm hoping that getting some food in his tummy might settle him as he is increasingly agitated.

They are wary of sedating him since it may cause respiratory problems.

The next 24 hours are draining, a constant touch and go.

It is hard to see him weak once more, especially since 48 hours ago he seemed stronger.

Click to continue reading Baby T's Story, Chapter 10

Baby T's Story, Chapter 8- Extubated

Monday 2/27/12

CPAP involves them turning down the vent settings so that Baby T is encouraged to breath more on his own.
The NPO order stands to allow them to extubate without complications
(if he vomits his stomach contents he might aspirate and develop pneumonia again).

During the morning rounds they go over the plan to extubate as CPAP is going well.
 We leave so that they can remove the vent. IB Dad and I are giddy and can barely contain our excitement.
Soon we are requested and we go to his bedside, we're so anxious to see him.

Baby T is struggling on the CPAP machine since it fits poorly and is leaking.
Intubation + botulism cause his cry to be little more than a raspy "mewwing" sound.
Frequent blood gases (labs which in his case always involve alot of pokes) are done to
make sure that he is tolerating the transition well.
There is a flurry of activity surrounding his crib but I kiss his cheeks
during the first opportunity I get.

IB Dad & I get to hold our son after 5 long days of being unable to.

Holding him is bittersweet.

He is putting so much energy into his breathing. 

He seems as weak as when we first brought him here. 

Our reunion isn't what I expected, was he stronger yesterday or did I imagine it?

The CPAP machine is constantly beeping (alarming) making it even more

difficult to relax and soak in this moment.

Respiratory therapists, nurses and pediatricians continue to monitor Baby T closely.

The decision to switch him to a high flow nasal canula is made and he seems slightly more comfortable.
The need to get frequent blood gases means another decision to

put in an arterial line in order allow easier lab draws (less pokes).

They warn us that Baby T may need to be intubated once more. He is struggling to breath without support
but with the blood gases coming back in the ok range, they continue to "wait and see".

 A rough night is had by all as we anxiously await the next day. 

IB Dad stays the night in the hospital with us since we’re terrified of him being intubated once more.

We sleep in shifts since now one of us can be bedside through the night but sleeping next to him during such an anxious period of time is a near impossibility.


Click to continue reading Baby T's Story, Chapter 9