DAVE'S TIPS FOR THE NICU

A venerable tome forged in the old Bethesda NICU by LCDR Carpenter

 

Every day, on every patient, ask yourself three questions

 

  1. How can I wean respiratory support?
  2. How can I decrease lab draws?
  3. How can I improve nutrition?

 

PRE-ROUNDS

 

This represents your first hands-on contact with the patient for the day. Arrive early enough to complete your pre-rounds before meeting with the resident prior to AM report (preferably by 0700). Work out the details with the resident. For each patient ask the nurse how the night went. REMEMBER: No one spends more time with the patient than the nurse. Our nurses are highly experienced professionals. Just ask and they will divulge upon you a huge amount of free information. Their clinical observations about the relative well-being of the patients are consistently accurate. At all times treat them with the respect they deserve, and they will do likewise. Neonatology is truly a team effort.

 

Perform a cursory lung, heart, perfusion and abdomen exam on each patient. Add to this a quick exam of any particular areas of concern raised by labs, nurse; notes, or previous diagnoses (e.g. head circumferences in a baby with hydrocephalus) . Note the patient's birth weight, present weight, EGA, and DOL. Review vitals for trends: temp instability, tachycardia, As/Bs, hypotension. Review gases and resp support for trends: mean airway pressure, rate, FiO2, acidosis, hypercarbia, etc. By now you should have a picture of whether or not your patient is the same, better or worse off than yesterday in a cardiorespiratory sense.

 

Review FEN. Record the following:

total fluid in cc/k/d

total out in cc/k/hr

serum and urine chemistries as appropriate

quality of urine (SG, pH)

ratio of OG to IV intake -~

exact amount of Na+, Ca+, K+ you are giving in meq/k/d

Review AM labs.

Discuss plans with resident informally so that TPNs and other crucial orders can be sent prior to AM rounds.

 

NOTES: Please make sure that your exam is reflected in the notes. No matter what style note you write, it should contain an assessment and plan presented in such a way that the reader gets the idea of whether the patient is better ,worse or the same. Repetition of every lab value is unnecessary.

 

ORDERS

 

DATE AND TIME all orders. Avoid verbals or sign in a very timely manner. Include "cc/kg" or "mg/kg" wherever possible so that nurses can protect you from errors. Sign and STAMP all orders (or print SSN plus name)

 

TPN and Fluids:

 

Most term infants can be started on 60-80 cc/k/d as maintenance IV fluids. Preemies tend to require 100-120 cc/k/d for starters. This is due to their increased insensible losses. Term babies are started on Dl0W while preemies get D5W. This is because the aim is to provide the infant with at least 6-8 mg/k/min of glucose to provide the brain with energy substrate and avoid utilizing protein for energy. If very small preemies were also given D10W to start, they would likely become hyperglycemic on their relatively high fluid volume needs (sometimes as high as 180-200 cc/kg/day) . Serum electrolytes (Chem1, Ca, Mg, Phosphorus)are usually checked at 12-24 hours of life (6-8 hours of life in infants < l000 g) to determine if standard electrolyte maintenance delivery is adequate.

 

As serum electrolytes stabilize over the first several days to weeks they usually can be spaced to once or twice weekly while infant is on IV fluid. If infant is off IV fluid you do not need to monitor the electrolytes unless there is a particular concern (e.g. hyponatremia). It is useful to include a full chem 1,2 and 3 with triglycerides weekly while on TPN. If the infant is ~ 1500gm or on prolonged TPN, after the first month an alk phosphatase should be checked (and monitored every 1-3 weeks thereafter if abnormal) to assess for metabolic bone disease.

NOTE: Admission orders require an initial glucose check but no more. Therefore it is imperative that you order routine glucose checks tailor-made to the patient's condition. For example, most infants can be managed by checking glucoses every 2-4 hours until stable, then spacing to every 6-8 hours for the first 2-3 days on IV fluids. After the first few days, patients still on IV fluids should continue to have glucose checked 2-3 times a day. If making a rapid (over 12-24 hours) transition from IV to P0 on a well, good-feeding term infant remember to check 3 or 4 qac glucoses. Those on full PO do not require routine glucose checks.

Fluid management in the first week of a micropreemie's life (<1000gm) is critical. Neonates are supposed to lose 5-l5~ % of their birth-weight as water in the first week of life. They are also to drop about 5 meq/kg in total body sodium during this same time. This process should be allowed to occur without our hindrance. Therefore our goal should be to provide only enough fluid to maintain normal vascular volume and serum sodium. Too much maintenance fluid or frequent boluses can cause hyponatremia or promote a patent ductus arteriosus. Electrolytes are monitored as often as every 6-12 hours to guide fluid therapy in the extremely low birthweight infant. Sodium is often not added in significant quantity (if at all) for the first 24-72 hours. Weight is often assessed every 12 hours. Fluid loss can be minimized by early placement of infant in isolette, and humidifying the infant's environment. It is important to have a good understanding of fluid homeostasis.

 

Micropreemies as well as bigger infants are expected to go through several stages of fluid homeostasis.

 

The prediuretic phase is seen in the first 24-48 hours and is marked by mild urine output of 0.5-1.5 cc/k/hr and minimal sodium dumping. The diuretic phase follows with urine output increasing to 3-5 cc/k/hr and a major excretion of sodium. Toward the end of the first week urine output slows to about 1.5-2.5 cc/k/hr and sodium excretion decreases. Your initial fluid management is guided mostly by weight change and serum / urine electrolyte values. An extremely premature newborn who has become hyponatremic probably does NOT have a low total body sodium amenable to increasing his/her sodium intake. More likely, he/she requires a reduction in total fluid INTAKE. The converse is true if such a newborn has become hypernatremic. REMEMBER: the newborn is supposed to give up sodium over the course of the first week, not gain it (I refer you to the relative scarcity of sodium in human milk)

 

TPN is started in about 2-3 days of life when the fluid and salt status have stabilized. TPN (in combination with OG feeds or not) is advanced to 150-160 cc/k/d as tolerated in order to provide adequate calories for growth. Infants need about 90-100 cals/kg of parenteral nutrition or 110-130 cals/kg of enteral nutrition in order to grow. TPN protein is begun when about 60 cal/k/d is reached via carbohydrates and lipids (or on second day by many attendings) at 0.5 g/k/d and advanced by 0.5 g/k/d to max 2.5 g/k/d. Lipids are begun on second day at 1.0 g/k/d and advanced by 0.5-1.0 g/k/d to max 3.0 g/k/d. Occasionally TPN lipid administration is delayed until after an infant's respiratory status has improved due to the theoretical concern of disturbances in oxidant-antioxidant balance (discuss with resident or attending) Zantac is added to TPN when the neonate is NPO to avoid stress gastritis. The easiest way to administer electrolytes is the following:

 

1) NaCL at 3 meq/k/d

2) K acetate at 1 meq/k/d

3) K phosphate at 1 meq/k/d

  1. Ca gluconate at 1.5 to 2.0 meq/k/d in preemies, 1.0 meq/k/d in term infants

5) Magnesium at 0.3 meq/k/d

 

Add heparin at 0.5 units/cc if central line. Also add multivitamins. Get advice on any other additives from the resident. It is important that the TPN fluid amount that you enter in the computer represent the total fluid you intend to give in cc/k/d for the next 24 hours. There are two main ways to write TPN volumes:

 

1) Write it as though it is the only fluid the infant will be getting ignoring any OG feeds. This has the advantage of allowing you to frequently change OG feed amounts and wean TPN rates without concern for delivering excessive amounts of salt, protein, etc. The disadvantage is that you will have to be careful in infants with excessive salt requirements. For example... A Case: 1000 g infant with severe hyponatremia, now corrected to serum Na 135 on 10 meq/k/day of Na.

 

TPN: entered on computer as l50 cc/k/day, Na 10 meqlk/day

OG: originally NPO, now getting 75 cc/k/day

TPN rate: originally delivered at 150 cc/k/day, now at 75 cc/k/day

Result: Infant receives only 5 meq/k/day from TPN and 1-1.5 meq/k/day from OG for total Na Intake of 6.0-6.5 rneq/k/day. This falls far short of goal.

 

2) A good alternative (writing a daily TPN for the exact amount of TPN that will be infused) has the advantage of making it easier to track the amounts of solutes you are giving. This is helpful when you are concerned about the potential for hyponatremia. It will require you to periodically adjust down the amount of salt and protein you have added since there will be some duplication of nutrients between OG and IV feeds. To clarify, imagine that an infant's total fluids are aimed at 150 cc/k/d. You are now giving 75 cc/k/d as OG. If you write your TPN volume for 75 cc/k/d but give 2.5 g/k/d protein, you may be disregarding the fact that another 1.5 g/k/d of protein is in the OG feeds. This total of 4.0 G/k/d of protein may be too much for your infant, so be careful to adjust the TPN contents as you continue "up/down feeds." Please take all calories and solutes into account each day. Some attendings include lipid in the total volume and some don't. Just ask.

 

Make daily increases in dextrose concentration as tolerated. If the infant has normal blood glucose levels you can increase the mg/k/min amount of glucose you give by about 10% per day to a max of 15 mg glucose/kg/min.

 

You will need to consider the volumes of drips, flushes and meds in your fluid and electrolyte calculations, especially when managing the micropreemie.

 

FEEDING

 

Term babies can be started on ad lib nipple 20 cal or breast milk feeds if they are "well." A good suck is usually not established until about 34-36 weeks. Therefore preemies often require that their first feeds be OG feeds. Extremely small preemies can be OG fed from day one if stable. Some attendings start with "minimal trophic feeds" of a constant infusion of about l0 cc/k/d for up to one week with the intention of "preparing" the gut for more voluminous feeds. Preemie OG feeds can be either by bolus or continuous. Rates of advancement are usually kept at about 10-25 cc/k/d. The rate of 10 cc/k/d is reserved for the smallest and sickest infants while advancements of 25 cc/k/d would be granted to the largest and most well premature infants. Recovering term infants can tolerate larger advancements or a more liberal feeding schedule. These advancement rates are intended to avoid feeding intolerance marked by increased residuals and abdominal distension) as a result of sluggish gut motility, and possibly even NEC. OG advancements are usually conducted as part of what is called "up and down feeds." This means you decrease the TPN rate by the same amount as you advance the OG feeds. When OG feeds represent approximately 2/3 of the total daily fluid intake you can stop the lipids. Remember that full formula or breast milk feeds will only provide about 1-1.5 meq/k/d of sodium. Therefore, as your TPN volume is increased sodium may have to be added to feeds or adjusted accordingly in the remaining TPN fluid!

 

In most cases the introductory OG feeds are given as 20 kca1 formula (special care for those < 34 weeks who could use the extra Ca and Phosphorus) or breast milk. These are advanced to 24 cal special care or fortified breast milk respectively in preemies when OG feeds comprise about 70-100% of the total daily fluids IF they need the extra calories. In other words, most 1900 g infants will not require 24 cal formula before achieving open crib status.

 

SCHEDULED LABS

 

Once a preemie is stable on TPN, typical labs include

Chem 1,

Ca, Mg, Phosph 1-2x per week,

Chem 2&3 and triglyceride weekly

alk phosph every 2-4 weeks,

microhematocrit or CBC 1-2x per week.

 

Blood gases vary from once daily if stable on CPAP or minimal vent settings to many times per day. Babies on vents typically get a CXR every 1-4 days or as needed.

 

RESPIRATORY

 

"The sun never rises or sets on a good gas." Good blood gases are opportunities to wean support. All preemies who reach extubatable settings probably deserve a trial of extubation unless you are convinced they need to "grow on the vent". Extubatable settings vary from attending to attending but are typically:

rate 10-15

PIP 12-14

PEEP 3-4

FiO2 < 40%

 

Oxygenation is affected by mean airway pressure, FiO2, inspiratory time, PIP, PEEP, and somewhat by rate. Ventilation (or PCO2) is affected by rate and tidal volume as a function of PIP minus PEEP (or "delta p"). Both oxygenation and ventilation are also often affected by lung disease, mechanical problems (e.g. right mainstem endotracheal tube) , and hemodynamic problems like shock or PDA) . Do not overlook these. Typical parameters for an arterial gas are pH of 7.35 to 7.45 ( a pH of 7.25 may be acceptable in a micropreemie with BPD), pCO2 of 35 to 45 (as high as 60 in a micropreemie with BPD), p02 of 50 to 70 in a micropreemie and 65 to 90 in bigger preemies and term kids. A base deficit of up to - 3.0 to -4.0 is acceptable. Capillary gases tend to have relatively lower pH and higher pCO2 (by about 4 or 5 torr) , and uninterpretable p02 values (so don't bother mentioning them) . I caution you to make sure you note the FiO2 prior to ordering a vent change. This is often overlooked. A FiO2 above 50% does not usually indicate making a decrease in mean airway pressure (exception: to reduce barotrauma in a patient with PIE)

 

Count on ordering AM chest films on infants on ventilators (unless they are chronically intubated and "growing on the vent")

 

CARDIOVASCULAR

 

Murmurs in preemies, although most often innocent, should be investigated. Be on the lookout for PDA as marked by wet lungs, increased heart size, murmur, increased pCO2, increased 02 requirement and widened pulse pressure (>25 mm Hg).

 

GI

 

Bilious emesis is always bad. Work it up rapidly and aggressively. It is often seen with ileus, NEC, obstruction, malrotation with volvulus, atresia, etc (ALL BAD)

NEC rarely occurs without abdominal distension. It is heralded by bloody stools, distension, residuals, bilious emesis, As/Bs, shock, acidosis, lethargy, neutropenia, hypo- or hyperglycemia. Management involves antibiotics, serial films, bowel rest, and surgery.

 

Heme

 

The secret to avoiding transfusions is to draw less blood.

 

Monitor only spun Hct if possible.

 

 

Bili

 

There is no room for me to go into an essay on hyperbilirubinemia. A direct bili above 1.5-2.0 is always abnormal. Always determine if an infant with jaundice is a "setup' for immune hemolytic disease by checking baby's blood type vs mom's blood type, and coombs test.

 

Choosing when to put an infant on phototherapy is challenging. It is based on the rate of rise of serum bilirubin, age of the infant, and whether or not the infant has hemolysis.

**The only purpose of phototherapy is to avoid exchange transfusion. Therefore you should decide on your exchange level first. Term babies without hemolysis would probably be exchanged at about a level of 25 or more these days. Preemies are considered for exchange at around 20-25 ( or 15-20 if extremely small or within first 24 hours) . Choose your light levels to avoid these exchange levels.

 

ID

 

Empiric antibiotics are used in a child at risk for or suspected of having sepsis. Amp & Gent are used for work-ups in first day or so of life. Vanc & Claf are used thereafter. I recommend you avoid ordering Vanc or Gent levels until you know these antibiotics will be continued beyond 48-72 hours. The neofax doses are quite reliable. The only purpose of antibiotic blood levels is to guide long-term therapy. Exception: a 24 hr trough in the ELBW infant who tends to have marginal renal function, or any baby with questionable renal function, is very useful.

 

Never bag for urine culture. Do cath or suprapubic only. Do not reuse cath if first pass goes into vagina on girls or alongside glans on boys.

 

Always report on rounds the expected length of treatment with each antimicrobial, and how many days are completed.

 

NEURO

 

All preemies less than 1500 g or with critical illnesses or with abnormal neuro exams need head U/S. If not an immediate concern this can be performed any time during first week. If normal a repeat U/S is usually done at one month or some time prior to discharge. Wednesday is HUS day.

 

ROP

 

Done on all preemies born prior to 32 weeks and < 1500 g when they reach 32 weeks corrected age. Most often done on Tuesday.

 

HEARING SCREEN

 

To be eventually done on all newborns.

 

Currently a hearing screen is done on every infant admitted to the NICU. Infants most at risk are those…

 

  1. <1500 g
  2. history of exposure to ototoxic drug >= 5 days
  3. significant neuro history
  4. as indicated by syndromic features. Infants with neurological concerns or syndromic features should get a BAER instead of an OAE.

 

METABOLIC SCREEN

 

PLEASE make sure each baby gets one prior to the first transfusion (best if first day of life) and another at around 2 weeks of life when on significant nutrition.

 

IMMUNIZATIONS

 

Keep up with these as you would a well baby if the patient can tolerate. If a baby is stable he or she can receive the hep vaccine at any time. No OPV in the nursery (we instead use IPV)

 

OTHER THINGS ON THE AGENDA

 

1) Try to attend AM report whenever possible, 0745-0900.

2) AM round start at 1000 when possible.

3) Be ready to start check-out at 1700 on weekdays and 0830 on

weekends.

 

 

FORMULAS AND CALCULATIONS

 

Respiratory

ETT size: ETT depth:

 

<1 kg = 2.5 1 kg = 7cm

1-2kg = 3.0 2 kg = 8cm

2-3kg = 3.5 3 kg = 9cm

>3 kg = 3.5-4.0 >3 kg = 9-10cm

 

Minute ventilation: MV = (TV-dead space) X RR

 

TV is usually 6-8 cc/kg, dead space is usually 2-2.5 cc/kg MV is usually 250-400 cc/k/mm

 

Mean Airway Pressure: MAP = (RR X IT X PIP) + (RR X ET X PEEP)

60

 

Oxygenation Index (if > 40 consider ECMO):

 

OI = (FiO2 x MAP x 100) / PaO2

 

Oxygen difference (normal 15-30. Useful in PPHN. If > 610 consider ECMO)

 

A-aDO2 = [(FiO2) (713)-(PaCO2/0.8)] - PaO2

 

Alveolar-Arterial ratio (in RDS, if 0.22 consider Survanta)

 

A-a ratio = PaO2/PAO2

 

where PAO2 = FiO2 X 713 - PaCO2

the "713" represents Patm-PH20 which is 760-47

 

Oxygen Content (in units of cc O2 / 100cc)

 

(Hb)(1.34cc02/g Hb) (%02 sat) + (.003)(PaO2)

 

Oxygen consumption: 6-8 cc/k/mm

 

Ventilatory Efficiency Index

 

3800/(delta-P x RR x PaCO2)

 

applies when no spontaneous respirations.

index increases when ventilation and lung function improve

 

Fluid/Electrolytes/Nutrition

 

mg Glucose/kg/mm (max is 15) (aka "em-kay-ems")

 

MKM = D x rate (cc/hr)

6 x wt[kg]

 

To determine Kcal from glucose:

 

(D X cc/kg/d x 4 [kcal per gr] ) /100 = # kcal/kg/d from glucose

 

Insulin drip (usually run in range of 0.01-0.03 u/kg/hr)

 

10 X wt [kg] = # units to mix with 7 cc 5% Albumin and QS 100 cc with D5W. Therefore, 0.2cc/hr = 0.02u/kg/hr

 

To diurese a patient:

 

Give 4cc / kg 25% Albumin followed by 1.0 mg/kg Lasix

 

To correct a metabolic acidosis:

 

(base deficit) (wt) (0.3) = #meq of bicarb to give at strength of 0.5 meq/ml over 30 to 60 mm

 

*Note: usually do a half correction number in half and give

 

To mix dopamine or dobutamine (same way for either)

 

60 x wt [kg] = #mg of dopamine or dobutamine to add to l00 cc of

D5W (or NS) so that 0.l cc/hr = 1 mcg/kg/min

 

Fractional excretion of sodium (> 3% suggests ATN)

 

FeNa = (100 x UNa [meqlL] / Ucr[mg/dl] ) / (Pna [meq/L] / Pcr [mg/dl])

 

Pna = plasma sodium, PCr = plasma creatinine, Una = urine sodium,etc

 

Serum osmolarity

 

sOSM = 2 x Na + Glu/18 + BUN/2.8

 

Anion Gap ( normally 12 +/- 2)

 

AG = Na - Cl - Bicarb

 

Cardiovascular

 

UAC depth (cm) : 3 X wt [in kg] + 9

UVC depth(cm) : 0.5 X (UAC depth) + 1

 

*Note: do not round off these measurements for lines

 

Heme-bili

 

To transfuse to desired Hct

 

#cc to transfuse = (desired Hct - actual Hct) (80) (wt) / 70

80 = plasma volume in cc/kg

70 = Hct of PRBCs

 

Digitally remastered by LT Gorman, gregory_h.gorman@wramaa.chcs.amed.army.mil