Invasive procedures are a necessary but potentially risk-laden part of newborn intensive care. To provide maximum benefit, these techniques must be performed in a manner that both accomplishes the task at hand and maintains the patient’s general well-being.
I. GENERAL PRINCIPLES
A. Consideration of alternatives. For each procedure, all alternatives should be considered and risk-benefit ratios evaluated. Many procedures involve the placement of indwelling devices made of plastic. Polyvinylchloride-based devices leach a plasticizer, Di(2-ethylhexyl)-phthalate (DEHP), which may be toxic over long-term exposure. Alternatives exist, and devices that are DEHP-free should be used for procedures on neonates whenever possible.
B. Infection control. For any procedure, care should be taken to ensure antisepsis. The optimal agent to use for an infant is not clear; chlorhexidine (for patients with mature skin) and alcohol are common choices. It is important to avoid chemical burns caused by iodine solution by carefully cleaning the skin with sterile water after the solution has dried. For extremely preterm infants (<28 weeks), alcohol can also cause a chemical burn and should be washed off with sterile water as mentioned earlier.
C. Monitoring and homeostasis.
Ideally, the operator should delegate another care provider to be responsible for the ongoing monitoring and management of the patient during a procedure. This person’s primary focus should be on the patient rather than the procedure being performed. They must
assess cardiorespiratory and thermoregulatory stability throughout the procedure and apply interventions when needed. Continuous cardiorespiratory monitoring can be accomplished through a combination of invasive (e.g., arterial blood pressure monitoring) or noninvasive (e.g., oximeter) techniques. For sterile procedures, a particularly important function is ensuring the integrity of the sterile field.
This monitoring can most effectively be standardized through the use of a procedure checklist so that the monitoring caregiver can ensure that each step is appropriately completed and documented by signoff on the part of all providers at the conclusion of the procedure.
D. Pain control.
Treatment of procedure-associated discomfort can be accomplished with pharmacologic or nonpharmacologic approaches (see Chapter 70
). The potential negative impact of any medication on the patient’s cardiorespiratory status should be considered. Oral sucrose (e.g., 24% solution, 0.2 to 0.4 mL/kg) is very effective in reducing pain of minor procedures including blood drawing. It can also be used as adjunctive therapy for more painful procedures when the patient can tolerate oral medication. Either morphine or fentanyl is commonly administered before beginning potentially painful procedures. The use of neonatal pain scales to assess the need for medication is recommended.
E. Informing the family. Other than during true emergencies, we notify parents of the need for invasive procedures in their child’s care before we perform them. We discuss the indications for and possible complications of each procedure. In addition, alternative procedures, when available, are also discussed. Informed consent should be obtained for procedures with a significant degree of invasiveness or risk.
F. Precautions. The operator should use universal precautions, including wearing gloves, impermeable gowns, barriers, and eye protection, to prevent exposure to blood and bodily fluids that may be contaminated with infectious agents.
G. Time out and checklist. Before beginning any procedure, the entire team should take a “time out” or “safety pause” to ascertain that the correct procedure is to be performed on the correct patient and, if appropriate, on the correct side (e.g., thoracostomy tube). This pause should be incorporated into a complete checklist that includes all the steps of the procedure. Use of such a list helps ensure that a key step or assessment is not inadvertently omitted.
H. Education and supervision. Individuals should be trained in the conduct of procedures before performing the procedure on patients. This training should include a discussion of indications, possible complications and their treatment, alternatives, and the techniques to be used. For some procedures, there are mannequins or other options for simulation training, which also offer the opportunity to refine team skills. Experienced operators should be available at all times to provide further guidance and needed assistance.
Careful documentation of procedures enhances patient care. For example, noting difficulties encountered at intubation or the size
and insertion depth of an endotracheal tube (ETT) provides important information if the procedure must be repeated. We routinely write notes after all procedures, including unsuccessful attempts. We document the date and time, indications, performance of the time out, monitoring, premedication for pain control, the techniques used, difficulties encountered, complications (if any), and results of any laboratory tests performed.
II. BLOOD DRAWING. The preparations for withdrawing blood depend somewhat on the studies that are required.
A. Capillary blood is drawn when there is not a need for large volume of blood.
1. Applicable blood studies include hematocrit, blood glucose (using glucometers or other point-of-care testing methods), bilirubin levels, electrolyte determinations, and occasionally blood gas studies.
a. The extremity to be used should be warmed to increase peripheral blood flow.
b. The skin should be cleaned carefully with an antiseptic such as alcohol or povidone-iodine before puncture to avoid infection of soft tissue or underlying bone.
c. Capillary punctures of the foot should be performed on the lateral side of the sole of the heel, avoiding previous sites if possible.
d. Spring-loaded lancets minimize pain while ensuring a puncture adequate for obtaining blood. The blood should flow freely, with minimal or no squeezing. This will ensure the most accurate determination of laboratory values.
B. Venous blood for blood chemistry studies, blood cultures, and other laboratory studies can be obtained from a peripheral vein of adequate caliber to enable access and withdrawal of blood. The antecubital and saphenous veins are often promising sites. For blood cultures, the area should be cleaned with an alcohol or iodine-containing solution; if the position of the needle is directed by using a sterile gloved finger, the finger should be cleaned in the same way. A new sterile needle should be used to insert the blood into the culture bottles.
C. Arterial blood
may be needed for blood gases, some metabolic studies, and when the volume of blood needed would be difficult to obtain from a peripheral vein and no indwelling catheter is available. Arterial punctures
usually involve the radial artery or posterior tibial artery. Rarely, the potential risk of brachial artery puncture may be justified when no other site is available. Radial artery punctures are most easily done using a 25G to 23G butterfly needle, and transillumination often aids in locating the vessel. Traditionally, an Allen test is performed to ensure collateral perfusion. (Recently, it has become controversial whether or not the Allen test should be considered standard of care, especially regarding the interpretation of an abnormal test.) The radial artery is identified and entered with the bevel of the needle facing up and at a 15-degree angle against the direction of flow. If blood is not obtained immediately during insertion, the needle may
be advanced until the artery is transfixed and then slowly withdrawn until blood flow occurs.
D. Catheter blood samples
1. Umbilical artery or radial artery catheters are often used for repetitive blood samples, especially for blood gas studies.
a. A needleless system for blood sampling from arterial catheters should be used. Specific techniques for use vary with the product, and the manufacturer’s guidelines should be followed.
b. For blood gas studies, a 1-mL preheparinized syringe, or a standard 1-mL syringe rinsed with 0.5 mL of heparin, is used to withdraw the sample. The rate of sample withdrawal should be limited to 1.5 mL/minute to avoid altering downstream arterial perfusion.
c. The catheter must be adequately cleared of infusate before withdrawing samples to avoid false readings. After the sample is drawn, blood should be cleared from the catheter by infusing a small volume of heparinized saline-flushing solution.
III. INTRAVENOUS THERAPY. The insertion and management of intravenous catheters require great care. As in older infants, hand veins are used most often, but veins in the foot, ankle, and scalp can be used. Transillumination of an extremity can help identify a vein, and newer devices that enhance the detection of veins may be even more useful.
IV. BLADDER CATHETERIZATION
A. A sterile technique is crucial. Careful cleaning with an antiseptic such as alcohol or an iodine solution over the prepubic region is essential.
B. Technique. The urethral meatus is identified, and a small gauge (3 French to 5 French) silicone catheter is gently advanced into the bladder, with care taken to keep the distal end of the catheter sterile until the urine sample is collected. Resistance to insertion should be minimal. If obstruction is sensed, it is usually best to abort the procedure and consult urology as indicated.
V. LUMBAR PUNCTURE
1. The infant should be placed in the lateral decubitus position or in the sitting position with legs straightened. The assistant should hold the infant firmly at the shoulders and buttocks so that the lower part of the spine is curved. Neck flexion should be avoided so as not to compromise the airway.
2. A sterile field is prepared and draped with towels, and the skin of the back cleansed with antiseptic solution. Chlorhexidine should not be used on the skin prior to a lumbar puncture (LP) as it is specifically not intended to be introduced into the central nervous system.
3. A 22G to 24G spinal needle with a stylet should be used. Avoid the use of a nonstylet needle, such as a 25G butterfly needle, as this may introduce skin tissue into the subarachnoid space.
4. The needle is inserted in the midline into the space between the fourth and fifth lumbar spinous processes and angled slightly superior to follow the intervertebral space. The needle is advanced gradually in the direction of the umbilicus, and the stylet is withdrawn frequently to detect the presence of spinal fluid. In infants, the insertion distance is only a few millimeters. Usually a slight “pop” is felt as the needle enters the subarachnoid space.
5. The cerebrospinal fluid (CSF) is collected into three or four tubes, each with a volume of 0.5 to 1.0 mL.
B. Examination of the spinal fluid. CSF should be inspected immediately for turbidity and color. In many newborns, normal CSF may be mildly xanthochromic, but it should always be clear.
1. Tube 1. Glucose and protein determinations should be obtained.
2. Tube 2. Cell count and differential should be determined from the unspun fluid.
3. Tube 3. Culture and sensitivity studies should be obtained.
4. Tube 4. The cells in this tube also should be counted if the fluid is bloody. The fluid can be sent for other tests (such as polymerase chain reaction amplification for herpes simplex virus [HSV], etc.).
C. Information obtainable
1. When the CSF is collected in three or four separate containers, a red blood cell (RBC) count can be measured on the second and last tubes to see if there is a decrease in the number of RBCs per cubic millimeter between the first and last specimens. In fluid obtained from a traumatic tap, the final tube may have fewer RBCs than the second; more equal numbers suggest the possibility of an intracranial hemorrhage, but the sensitivity and specificity of this finding are low. The presence of blood may be due to either the technical difficulty of obtaining a sample from a small patient or the small amount of partuitional bleeding that can normally result from birth.
2. White blood cell (WBC) count.
The normal number of WBCs per cubic millimeter in newborns is a matter of some controversy, and different practitioners may accept different numbers of cells as normal, including the presence of some polymorphonuclear cells. Data obtained from infants in a neonatal intensive care unit (NICU) have shown that the upper limit (95th percentile) of CSF WBC count is 12 cells/µL in preterm infants and 14 cells/µL in term infants. If there is contamination of the CSF sample with RBCs, there is no reliable method to “correct” the WBC. In infants with proven meningitis, higher WBC counts are generally seen when the infection is caused by gram-negative organisms rather than in group B streptococcal disease; as many as 50% of the latter group will have 100 WBCs/mm3
or less. Because of the overlap between normal infants and those with meningitis, the
presence of polymorphonuclear leukocytes in CSF deserves careful attention. Ultimately, the diagnosis depends on culture results and clinical course.
Table 69.1. Cerebrospinal Fluid Examination in High-risk Neonates without Meningitis
White blood cell count (cells/mL)
No. of infants
±2 Standard deviations
Percentage of polymorphonuclear cells
No. of infants
No. of infants
Glucose in cerebrospinal fluid divided by blood glucose (%)
No. of infants
Source: From Sarff LD, Platt LH, McCracken GH Jr. Cerebrospinal fluid evaluation in neonates: comparison of high-risk neonates with and without meningitis. J Pediatr 1976;88(3):473-477.
Data on glucose and protein levels
in CSF from high-risk newborns are shown in Table 69.1
. Normally, the CSF glucose level is approximately
80% of the blood glucose level for term infants and 75% for preterm infants. If the blood glucose level is high or low, there is a 4- to 6-hour equilibration period with the CSF glucose.
The normal level of CSF protein in newborns may vary over a wide range. CSF protein levels are higher in preterm infants (upper limit 209 mg/dL) than in term infants (159 mg/dL), and this declines with increasing postnatal age. The level of CSF protein in the premature infant appears to be related to the degree of prematurity.
No single parameter can be used to rule out or rule in meningitis. Meningitis may occur in the absence of positive blood cultures (see Chapter 49
A. Endotracheal intubation. In most cases, an infant can be adequately ventilated by bag and mask so that endotracheal intubation can be performed as a controlled procedure.
1. Tube size and length.
The correct tube size (see Chapter 4
) and insertion depth can be estimated from the infant’s weight as well as by several other methods based on weight and gestational age. For insertion depth of oral ETTs, the most common rule is wt (kg) + 6 cm. A simple estimation for very premature infants is the naso-tragus distance + 1 cm. It is most important to remember that all of these methods are estimates, and insertion depth must be confirmed by physical examination and radiograph if the tube is to remain in place.
Only gold members can continue reading. Log In