Physical Therapy for Neonates with Respiratory Dysfunction

LINDA CRANE, MMS

Chest physical therapy for neonates with pulmonary dysfunction is a growing specialty of physical therapy practice. The purpose of this article is to provide physical therapists current information regarding chest physical therapy for the newborn infant. The neonatal diagnoses for which chest physical therapy is useful or has good rationale are discussed. Common complications are reviewed that affect physical therapy and medical treatment for infants with respiratory diseases and prematurity. Specific indications, contraindications, and precau­tions for physical therapy techniques are listed. Chest physical therapy evalua­tion and treatment are described and rationale for the application of various techniques is provided. Literature is reviewed dealing with the effects of chest physical therapy on neonates with pulmonary dysfunction. The strengths and weaknesses of each reviewed study are analyzed and suggestions for direction of future research for physical therapists are provided.

Key Words: Infant, newborn; Pulmonary disorders; Respiratory therapy, Physical therapy.

As the quality of care provided to perinatal patients improves, an increasing number of high risk new­borns survive the neonatal period. Optimal treatment of the high risk neonate requires a high level of care by a well-trained health care team. The extent of physical therapy involvement depends upon the will­ingness of physical therapists to recognize their role in the neonatal intensive care unit (NICU).

Chest physical therapy (CPT) for neonates is under as much scrutiny as the therapy is for other groups of patients. The "state of the art" is incomplete and distorted because of a lack of accurate and relevant research. Pringle, Kaminski, and Raymond reported that approximately 59 percent of physical therapists who responded to their survey did not evaluate or treat infants under three months of age for pulmonary or other problems.1 Yet, CPT is often described as part of the routine care of neonates with respiratory problems.2-8 The purpose of this article is to provide information and direction for physical therapists in­terested in the CPT component of neonatal care.

Chest physical therapy in this article refers to the bronchial drainage techniques of positioning, percus­sion, vibration, and airway suctioning. Choice and modification of the techniques are based on specific indications and contraindications at any given point

in time for each individual infant. Additional tech­niques usually considered part of CPT—breathing exercises and pulmonary rehabilitation—do not ap­ply to newborn infants.

ANATOMIC AND PHYSIOLOGIC DIFFERENCES

Several structural and functional differences from older children and adults make neonates more vul­nerable to respiratory distress. A newborn has a high larynx enabling the epiglottis to guide the larynx up behind the soft palate to produce a direct airway from the nasal cavity to the lungs. Newborns are, therefore, obligate nose breathers who can almost simultane­ously breathe and swallow until two to three months of age.9 A newborn infant's ribs are positioned hori­zontally, and the intercostal muscles are weak, result­ing in a predominantly abdominal (diaphragmatic) pattern of breathing.7

A neonate's lungs are less compliant, but his chest wall is more compliant than that of an adult.10, 11 This difference can lead to an increase in both airway resistance and obstruction. The narrow diameter of the infant's airway and a weak or absent cough reflex can also lead to airway obstruction.7

The newborn or premature infant is highly suscep­tible to diaphragm fatigue and compensates for res­piratory difficulty by increasing the rate rather than the depth of ventilation.7, 10 All the above factors, although normal for a neonate, contribute to respi­ratory distress and possible respiratory failure.

Ms. Crane is Assistant Professor, Department of Pediatrics, School of Medicine, and Division of Physical Therapy, School of Commu­nity and Allied Health, University Station, University of Alabama in Birmingham, Birmingham, AL 35294 (USA).

1764 PHYSICAL THERAPY

DISEASES

Chest physical therapy should not be prescribed merely in association with a diagnosis, but for any situation that might interfere with a neonate's venti­lation, airway clearance, or work of breathing. Several diseases and conditions of the neonate, especially the premature neonate, may decrease airway clearance and ventilation, or may increase the work of breath­ing. When the above problems are expected or antic­ipated in association with a specific disease, prophy­lactic use of CPT may be indicated. Some major diseases and conditions of the neonate in which CPT is indicated are described below.

Idiopathic respiratory distress syndrome (IRDS— hyaline membrane disease), the most common cause of respiratory distress in the newborn, is related to insufficient levels of surfactant in the lung.12 Idio­pathic respiratory distress syndrome is most often associated with prematurity, Caesarean section deliv­ery, maternal diabetes, perinatal asphyxia and shock, and the second born of twins. Symptoms usually appear within 2 to 3 hours after birth with progressive deterioration occurring within 24 to 48 hours.13 Prom­inent clinical signs include increased respiratory rate, expiratory grunting, intercostal and sternal retrac­tions, nasal flaring, and a seesaw pattern of ventilation between the chest wall and abdomen.14 Most mortal­ities from IRDS occur within 72 hours after birth and recoveries begin after 72 hours.13 The major patho­physiologic manifestation of IRDS is hypoxemia re­sulting from perfusion of atelectatic air spaces.15

Medical treatment of infants with IRDS is sup­portive and generally includes oxygen therapy, ther­mal regulation, humidification, nutrition, and assisted ventilation using some type of continuous distending airway pressure (CDAP).13 If mechanically assisted ventilation is required, generally the course of the disease is prolonged and severe and the incidence of complications increases. Common pulmonary com­plications secondary to intubation, mechanical ven­tilation, and oxygen administration include oxygen toxicity, bronchopulmonary dysplasia, pneumo­thorax, pneumonia, sepsis, increased mucous produc­tion, mucous plugging, and residual pulmonary dis­ease.9, 16-18

Chest physical therapy for infants with IRDS is directed toward prevention of complications that af­fect airway clearance. Bronchial drainage techniques are begun when signs of atelectasis, infiltrate, or uncontrolled secretions are noted clinically or by radiographs.

Meconium aspiration syndrome (MAS) results from aspiration by the fetus or neonate of meconium-stained amniotic fluid.19 The syndrome occurs most frequently in full-term, postmature, and intrauterine growth-retarded infants.3 Passage of meconium by

the fetus is the result of intrauterine distress, usually hypoxia, which also stimulates deep gasping and subsequent aspiration of meconium stained amniotic fluid. The severity of the syndrome depends on the amount of meconium that enters the lungs.19 Respi­ratory distress usually develops within 12 to 24 hours after birth. Tachypnea is the most prominent sign of respiratory distress.3 Many infants are neurologically depressed at birth and have low Apgar scores due to fetal asphyxia.2 Infants with MAS have hyperinfla­tion of the lungs with a characteristic barrel-chested appearance. Bronchiolitis, pneumonitis, cor pulmon­ale, atelectasis, air leaks, and persistent fetal circula­tion are possible complications of MAS.19 Most in­fants with MAS who survive recover within 7 to 10 days.

Medical treatment is largely supportive. Prompt suctioning, under direct view, of the pharynx and trachea immediately after delivery may be preven­tive.20 Antibiotic therapy, assisted ventilation with positive end expiratory pressure (PEEP), and supple­mental oxygen are often used.19 Close monitoring for signs of pneumothoraces is essential.

Types of CPT include immediate positioning, per­cussion, vibration, and suctioning. Bronchial drainage techniques should be continued until the secretions are free from meconium. Therapy may need to con­tinue for several days to ensure optimal clearance of airway and to help prevent secondary lower respira­tory tract infection.

Bronchopulmonary dysplasia (BPD) is a chronic lung disease often preceded by an acute respiratory problem, high concentrations of inspired oxygen, pos­itive pressure ventilation, and pulmonary interstitial emphysema.21, 22 The disease progresses from an acute stage (similar to IRDS) in the first three days to a chronic phase with atelectasis, emphysema, and cystic formations in the lung after one month.21 Ironically, though oxygen therapy may be an etiologic factor, the requirement for supplemental oxygen increases as the disease progresses and a vicious cycle is estab­lished. Morbidity and mortality rates are very high in BPD, but the lesions may be reversible if the infant can be protected from complications and provided with sufficient time to grow new lung tissue.3

Prevention is the hallmark of medical care for BPD. If prolonged ventilation and oxygenation are required, CDAP, reversing the inspiratory to expira­tory ratio, ventilating with low peak pressures, and PEEP may retard the progression of BPD. Frequent bronchial drainage is beneficial in treating infants with BPD.2, 21

Surgery on the chest and upper abdomen increases the patient's risk of developing pulmonary compli­cations. Neonates who have undergone surgical repair for abnormalities including, but not limited to, dia-

Volume 61 / Number 12, December 1981 1765

phragmatic hernia, esophageal atresia, and tracheo­esophageal fistula often require CPT.23

Neonatal pneumonia should be considered in the differential diagnosis for any neonate with respiratory distress.3 Pneumonia may develop at any point in the neonatal period. Conditions that increase the neo­nate's risk of developing pneumonia include: 1) pre­mature rupture of the membranes, 2) intrauterine asphyxia, 3) prematurity, 4) intubation and mechan­ical ventilation, and 5) thoracic or upper abdominal surgery with general anesthesia. Clinical symptoms of pneumonia in a neonate resemble those of IRDS.24

The most common organism responsible for neonatal pneumonia is β-hemolytic streptococcus (group B), followed in frequency by Listeria monocytogenes, tox­oplasmosis, cytomegalic virus, respiratory syncytial virus, Streptococcus pneumoniae, Streptococcus bovis, and Haemophilus influenzae? Broad spectrum antibi­otics are used to treat neonatal pneumonia. Preventive measures include routine cultures, strict aseptic air­way management, and antibiotic prophylaxis.3 The value of bronchial drainage techniques has been ques­tioned in treating patients with uncomplicated lobar pneumonia.25 However, the author and others believe that CPT is beneficial in patients with pneumonia

A. Clinical signs indicating problems with airway clearance 1. Rales and rhonchi on auscultation 2. Infiltrates or atelectatic areas on chest

roentgenogram, or both 3. Palpable crackles (rhonchal fremitus) 4. Audible crackles without stethoscope 5. Increased volume, viscosity, or purulence

of secretions suctioned 6. Apnea and bradycardia that do not respond

to stimulation or increased FIO2 B. Clinical signs indicating problems with ventila­

tion 1. Decreased or bronchial breath sounds on

auscultation 2. Areas of atelectasis on chest roentgeno­

gram 3. Signs of respiratory distress 4. Depressed CNS function 5. Recent abdominal or thoracic incision

C. "Situations" that may affect airway clearance, ventilation, or work of breathing 1. Endotracheal intubation 2. Tracheostomy 3. Mechanical ventilation 4. Oxygenation >50% 5. Restriction of positioning due to restraints,

type of assisted ventilation such as nasal CDAP

6. Hypothermia

Fig. 1. Criteria for chest physical therapy in neonates. One or more of these criteria should be present before initiating treatment.

and compromised airway clearance, especially in the last clearing-up stages of the infectious process.26

COMPLICATIONS

Some complications of infant respiratory diseases, syndromes, and their treatments that may affect CPT are 1) airleaks—pneumothorax, pneumomedias­tinum, pneumopericardium, 2) osteoporosis and rick­ets, 3) patent ductus arteriosus and congestive heart failure, 4) persistent fetal circulation, 5) tracheal and bronchial stenosis, 6) intracranial hemorrhage, and 7) apnea and bradycardia. (Two common complica­tions—BPD and pneumonia—have been discussed previously.) The complications listed above require the physical therapist to reassess the treatment tech­niques used with the affected infant. Close monitoring and modifications in treatment, as described below, are necessary when these complications occur.

Pneumothorax, pneumomediastinum, and pneu­mopericardium are the three most common results of alveolar air leaks. Pneumopericardium usually occurs in association with pneumothorax and pneumome­diastinum and may produce cardiac tamponade. Pneumomediastinum is often benign and requires no special therapy.3 Pneumothorax is the result of an alveolar rupture into the pleural space. This rupture may cause a localized collection of air, or may in­crease pressure within the intrapleural space, which results in decreased cardiac output, mediastinal shift, and severe respiratory distress.

Pneumothorax may be identified by a combination of clinical signs: irritability, cyanosis, tachypnea, rib cage retractions, nasal flaring, thoracic hyperreso-nance, abnormal chest radiograph, transillumination, shifted cardiac impulse, or a deviation of the trachea within the sternal notch.3 Breath sounds may be distant or absent on the affected hemithorax; how­ever, sounds are easily transmitted throughout the chest of an infant so this is not a reliable sign. Treatment of a large pneumothorax requires insertion of a chest tube attached to an underwater seal.3 A pneumothorax or other form of air leak is not a contraindication for CPT. The presence of a chest tube may, however, necessitate the use of vibration rather than percussion during bronchial drainage to adjacent bronchopulmonary segments.

Osteoporosis and rickets result when calcium, phos­phorus, and vitamin D and vitamin C requirements are not met. Hypocalcemia, hypophosphatemia, and vitamin deficiency syndromes are not uncommon in infants who cannot be fed orally because of imma­turity or respiratory distress.3 With these nutritional deficits, the bones are demineralized and more likely to fracture. When either osteoporosis or rickets is present, the fragility of the chest wall may contrain-dicate use of percussion during bronchial drainage.

1766 PHYSICAL THERAPY

TABLE 1 Contraindications to Bronchial Drainage Maneuvers in Neonates

Condition

Acute CHF Rib fracture Nasal CDAP Recent tracheo-esophageal fistula repair Recent eye or intracranial surgery Hemoptysis Untreated tension pneumothorax Intracranial hemorrhage

Trendelenburg's Position

X

X X X X

Prone Position

X

X

Percussion

X

X X

Vibration

X X

Endotracheal Suctioning

X (deep)

X

Patent ductus arteriosus (PDA) may be present and persistent at birth or may occur in response to hypox­emia.3 Shunting through the PDA may be in a right-to-left or left-to-right direction. This shunting of blood may exacerbate poor lung compliance by in­creasing pulmonary blood flow or by causing conges­tive heart failure (CHF). When CHF is present, the Trendelenburg's position may be poorly tolerated.

Persistent fetal circulation (pulmonary hyperten­sion of the newborn) is associated with 1) acute pulmonary vasoconstriction secondary to hypoxia, acidemia, or increased blood viscosity; 2) increased pulmonary vascular smooth muscle development sec­ondary to chronic hypoxia, fetal pulmonary artery hypertension, or specific congenital heart lesions; and 3) decreased cross-section area of the pulmonary vascular bed secondary to congenital hypoplasia or impaired lung growth. The result of persistent fetal circulation is right-to-left shunting of blood through the PDA and foramen ovale.27 The shunt causes venous admixture and greater hypoxemia. These in­fants are hemodynamically unstable until the pul­monary vascular resistance can be decreased. Infants with persistent fetal circulation may not tolerate CPT well or at all. They must be constantly monitored if treatment is begun.

Tracheal and bronchial stenoses are produced by trauma, granulation tissue, and fibrosis secondary to prolonged endotracheal (ET) intubation and repeated ET suctioning in neonates.3, 28 The type of suction catheter and suction techniques used are critically important in delaying or preventing stenosis and sub­sequent lobar atelectasis.28 Tracheostomy may be an alternative to prolonged ET intubation, but this ap­proach is controversial.

Intracranial hemorrhage (ICH) is most common in premature infants with respiratory distress. Coagu­lopathy and hemorrhage are complications in very small premature infants.3, 29 These problems can lead to decreased hematocrit levels, bruising, and ICH. Great care must be taken to rule out ICH before placing a small premature infant in Trendelenburg's position. Coagulation status must be normal before

administering a manual bronchial drainage tech­nique, such as percussion.

Apnea and bradycardia are common in premature infants. Bradycardia often occurs if apnea persists for more than 30 seconds.2 Apnea and periodic breathing may be caused by poor central respiratory drive or mechanical difficulties in the lungs.3 Apnea may also be secondary to hypothermia or hyperthermia, airway obstruction, vasovagal response to feeding or ET suctioning, sepsis, ICH, IRDS, hypoglycemia, and hypocalcemia.30 Mild apnea may be stopped by phys­ically stimulating the infant. Severe apnea and brady­cardia require assisted ventilation with an inspired oxygen concentration (FIO2) of 100 percent and ET suctioning to clear an obstructed airway.

Small and premature infants have a higher oxygen cost of breathing when compared with larger mature infants.31 Work of breathing increases with respira­tory distress. The net effect of increased work of breathing in small, sick neonates is hypoxemia. Any manipulation of the infant, including routine proce­dures, such as changing diapers, feeding, or auscul­tation of the chest, may result in further drops in arterial oxygen tension.32

INDICATIONS FOR CPT

Specific indications for CPT intervention in an NICU should be present before any treatment is begun whether treatment is directed toward solving an existing problem or preventing a potential prob­lem. For the neonate, CPT focuses on assisting airway clearance, improving ventilation, and decreasing work of breathing. One or more of the criteria listed in Figure 1 should be present before initiating treat­ment.

CONTRAINDICATIONS AND PRECAUTIONS

While there are few absolute contraindications for CPT (Tab. 1), there are many situations in which necessary precautions affect the therapist's assessment and treatment. The benefits of CPT must be weighed carefully against the potential risks incurred by spe-

Volume 61 / Number 12, December 1981 1767

cific techniques, and the infant's response to treat­ment must be carefully monitored at all times.

CHEST PHYSICAL THERAPY EVALUATION

Evaluation of the neonate with, or at risk for, pulmonary dysfunction should include review of the medical records, observation, auscultation, palpation, and review of current reports from the physician and nurse.

Review of the medical records should include the hospital chart, bedside flow sheets, arterial blood gas reports, chest radiograph reports, and any informa­tion pertinent to the infant.

Observation includes the following: 1) Signs of respiratory distress—intercostal and sub­

sternal retractions, nasal flaring, tachypnea or ap­nea, expiratory grunting, cyanosis or pallor, seesaw motion between the abdomen and chest wail, or head bobbing.

2) Skin condition—observe for such signs as break­down, bruising, or incisions.

3) Vital signs—compare against expected normal standards • Heart rate (120 to 140 bpm with a beat-to-beat variation3). • Respiratory rate (about 40 breaths a minute and irregular). • Blood pressure (systolic 80 ± 16 and diastolic 46 ± 16).

4) Posture and muscle tone—flexion should predom­inate.

5) Behavior—can range from eyes closed with regular respirations and no movement to eyes open, crying, and gross movement.

6) Temperature—the isolettes or warming beds have a servo-controlled mechanism to regulate the in­fant's temperature within the neutral thermal tem­perature zone (32-35°C).

Auscultation of the chest of a neonate, especially a premature infant, may not indicate localized changes in lung segments. Rapid respiratory rate, small tidal volume, thin chest wall, and ventilator noise are some factors that complicate auscultation for breath sounds and adventitious sounds. A gross assessment can be made and auscultation is still a vital component of the chest evaluation.

Palpation of the chest may reveal edema, subcuta­neous emphysema, palpable crackles or wheezes, po­sition of trachea in suprasternal notch (position of mediastinum), or rib fractures.

A verbal or written report from the infant's physi­cian or nurse may provide the most current infor­mation regarding the condition of the infant.

The physical therapist should also note the FIO2, type of equipment (such as oxyhood, pressure venti­lator, nasal CDAP), and mode of administration of ventilation (such as intermittent mandatory ventila­tion, assisted, controlled, PEEP).

CHEST PHYSICAL THERAPY

Chest physical therapy techniques for neonates with pulmonary dysfunction include bronchial drain­age (positioning, percussion, and vibration) and ET suctioning. Positioning for bronchial drainage uses the effect of gravity to move secretions from distal airways to larger, more central airways. Manual per­cussion and vibration of the chest wall are techniques to augment the movement of secretions within the airways. Positioning alone for drainage may require up to 30 minutes a position to be effective. With the addition of percussion or vibration, the time for each position is decreased to 3 to 5 minutes. If an infant's tolerance to CPT techniques is low, treating fewer lung areas a session is recommended rather than shortening the time for each position. Adequate time is especially important when attempting to clear se-

TABLE 2 Precautions for Bronchial Drainage Maneuvers in Neonates

Condition

Fragile skin (eg, sores, bruising) Chronic (treated) CHF Presence of chest tube Osteoporosis/Rickets Persistent fetal circulation Hyperactive airways Hyperactive gag Recent thoracic or abdominal surgery Cardiac arrythmias Apnea and bradycardia Severe respiratory failure Child who cries and acts irritated

(continuously) during procedure Subcutaneous emphysema of head and neck

Trendelenburg's Position

X

X

X X

Prone Position

X

Percussion

X

X X X X

X X X

X X

Vibration

X

X

X

X

Suctioning

X

X

1768 PHYSICAL THERAPY

Fig. 2a and 2b. Adapted equipment for use in neonate chest percussion. Shown left to right: nipple in a test tube, infant anesthesia mask, padded nursing nipple, padded medicine cup. Two views.

cretions from the narrow diameter airways of the neonate.

Positioning

Bronchial drainage (BD) may be used for neonates whether the positions for drainage are classical or modified. Contraindications and precautions for tilt­ing a newborn into a head-down position are included in Tables 1 and 2. When a specific lung, lobe, or segment is treated, the position used should be as close to the classical drainage position as possible to be most effective. Neonates being mechanically ven­tilated and those with umbilical artery catheters may be placed prone. A chest tube may necessitate modi­fication of the prone position to semiprone. Infants receiving nasal CDAP may not be positioned prone, and sidelying is often difficult also. A neonate in the Trendelenburg's position should never be left unat­tended.

Percussion

Manual chest percussion using the full hand, heel of the hand,33 or three to five tented fingers may be applied, when appropriate, to even the smallest infant. Several other methods of chest percussion requiring adapted equipment are also used. Examples of equip­ment are infant anesthesia masks, padded nursing nipples, padded medicine cups, and a nipple in a test tube (Figs. 2a and 2b). Regardless of the method used for chest percussion, the important technical consid­erations are maximizing control, enlarging the surface area to absorb the blow, and maintaining the cupping effect. Chest percussion is administered with motion primarily from the wrist, with firm support applied to the side of the thorax opposite that being percussed. Chest percussion should always be done with a thin blanket or towel covering the area being treated.

Percussion is well tolerated by most infants, but several contraindications and precautionary situa­tions (Tabs. 1, 2) may necessitate using vibration in lieu of percussion.

Vibration

Vibration of the chest is done manually by placing the fingers on the chest wall over the segment being drained and isometrically contracting the muscles of the forearm and hand to cause a vibratory motion. Excessive pressure against the chest wall should be avoided. When possible, vibration should be timed with the expiratory phase of respiration, although this is often impractical with the high respiratory rate of the newborn. Vibration can be generated mechani­cally using a variety of implements. One of the most common vibrators is a padded electric toothbrush. When any electric motor is used near high concentra­tions of oxygen, as in an isolette, extreme caution must be taken to avoid the hazards of explosion or fire. Both percussion and vibration are often used together with positioning for bronchial drainage when neither technique is contraindicated.

Endotracheal Suctioning

Suctioning is always a potentially dangerous pro­cedure. Endotracheal suctioning should be done only when needed—after bronchial drainage, when secre­tions are audibly bubbling within the ET tube or tracheostomy tube, when congestion is evident in the upper airway as noted by auscultation and palpation over the trachea, and during apnea and bradycardia unresponsive to physical stimulation and increased oxygen intake. All equipment should be set up and ready for use prior to initiating a CPT treatment in case an immediate need for suctioning occurs. A suggested procedure for suctioning is shown in Figure 3. This procedure, developed to minimize the hazards of ET suctioning, is based on a review of the literature and clinical experience.

Monitoring

Vital signs and clinical signs should be continually monitored during treatment. Transcutaneous oxygen (TCPO2) should be measured, when possible, to mon­itor the infant's response to treatment and to provide

Volume 61 / Number 12, December 1981 1 7 6 9

1. Preparation of the infant: Place the infant su­pine with his head slightly elevated. Place a small towel roll under the shoulders to slightly extend the head and neck.

2. Hyperventilation/Hyperoxygenation: Using a self-inflating bag with an attached face mask or artificial airway connector, administer 5 to 10 breaths with an oxygen concentration 10 to 20 percent higher than the infant was receiving before treatment. This procedure should be done before and after each pass of the suction catheter.

3. Lavage: This technique may be used for infants with tracheostomy or endotracheal tube. Instill 0.5 to 1.0 cc sterile normal saline solution, with a syringe, directly into the tube immediately before suctioning and after hyperventilation.

4. Suction: a. Using sterile procedure, check the vacuum

by occluding the suction part of the catheter in the gloved hand. Vacuum level should be 60 to 80 mmHg.

b. Wet the catheter with sterile saline or coat the catheter with sterile water-soluble lubri­cant.

c. Without applying suction, insert catheter into trachea. Apply suction for no more than 10 seconds as the catheter is withdrawn. Unless secretions are copius, a maximum of three passes with the catheter is recom­mended. Hyperventilation and hyperoxy­genation are performed after each pass of the catheter.

d. Suction the oral and nasal pharynges.

Fig. 3. A suggested procedure for endotracheal suction­ing for a neonate.

a warning of deterioration. The values for TCPO2 correlate with values for Pao2 unless peripheral blood flow is decreased, for instance in shock.34 Transcuta­neous carbon dioxide and pH monitors are also prov­ing to be reliable, simple, noninvasive monitors that are invaluable in a NICU.35

REVIEW OF LITERATURE: EFFECTS OF CPT IN NEONATES

Positioning for Bronchial Drainage

About three to five days after birth, newborn in­fants exhibit changes in heart rate and blood pressure values with position change similar to those seen in adults.36 Moss and associates concluded that vaso­motor regulatory mechanisms are intact in premature and full term infants at birth.37 A study comparing four different combinations of CPT techniques found slightly higher systolic blood pressure in infants treated in the head down position.38 In that study, neither heart rate nor blood pressure increased be­yond normal ranges.

The effects on arterial blood gases of sidelying or head down positioning may be significant in neo­nates. Finer and Boyd found no significant difference in Pao2 5 minutes before and 15 minutes after 20 minutes in the Trendelenburg's position in prone and supine.33 Crane and associates found no significant difference in TCPO2 between two groups who were treated in the Trendelenburg's position (20-30°) and two groups who were treated with the bed flat.38

Neither study included infants with unilateral lung disease. Zack and co-workers, however, found that position may have an effect on blood gas values in acutely ill patients with specific unilateral lung in­volvement.39 If arterial oxygen is low prior to treat­ment, the effects of positioning on oxygenation may necessitate compensatory measures.

Mellins stated that changing body position, as in bronchial drainage, may significantly affect the dis­tending pressure of the lung, and hence adversely affect the lung volume. He noted that functional residual capacity is greatest in the prone position, reduced in supine, and lowest in a head down posi­tion. Therefore, transpulmonary pressure, which will affect lung volumes, will vary depending upon posi­tion.40 Menkes and Britt, however, stated that position changes with bronchial drainage may improve the ventilation-to-perfusion relationship in obstructed areas of the lungs.41

No other studies of CPT in neonates have based comparisons on positioning. Some studies do not mention the drainage positions employed.

Percussion and Vibration

All studies that have examined the effects of CPT on neonates use some method of percussion or vibra­tion as a major component of the treatment. It is difficult to compare the results of these studies be­cause the treatment was administered differently in each.

In most studies evaluating the effect of CPT on Pao2 or TCPO2 chest percussion was manually ap­plied.34, 39, 42, 43 Two studies combined percussion and vibration over each lung area drained.42, 43 Holloway and associates reported a drop in Pao2 and Paco2 and a wider alveolar-arterial (A-a) oxygen gradient after CPT and suctioning.42 The suction procedure used did not include hyperventilation and hyperoxygena­tion. Once hyperventilation was provided, after suc­tioning, Pao2 returned to the pretreatment level.

Raval and associates found a significant decrease in TCPO2 in seven infants who received CPT, three different methods of ventilatory assistance, and ET suctioning.43 The CPT consisted of percussion and vibration for one minute with the infant in a head-up position and an additional minute in the head-down position. Endotracheal suctioning was done after the

1 7 7 0 PHYSICAL THERAPY

bronchial drainage. All subjects were intubated and mechanically ventilated. The TCPO2 dropped to a mean of 65 ±4 .5 mmHg and returned to base-line within four minutes. Increasing the FIO2 10 percent above that being delivered by intermittent mandatory ventilation, plus hyperventilating the infant, resulted in no mean drop in TCPO2. Hyperventilation of the infants with 100 percent oxygen resulted in hyperox-emia.

In their investigation of the effects of CPT on the weight of secretions removed by suctioning, Etches and Scott used a combination of percussion and vibration.44 The weight of secretions suctioned was significantly greater when their subjects received CPT than when no CPT was provided. The six newborns in the study all had a "pulmonary secretion problem" and were not chosen for the study merely on the basis of a specific diagnosis.

Finer and Boyd compared bronchial drainage alone with bronchial drainage and percussion.33 They reported a significant improvement in Pao2 for the group receiving bronchial drainage with percussion. Because the final arterial blood gas sample was taken only 15 minutes after treatment, long-term effects of treatment were not evaluated.

Crane and co-workers compared percussion with vibration in two different drainage positions.38 No significant difference in TCPO2 was found 30 minutes before and 5, 15, and 60 minutes after CPT. When percussion was used, there was a trend toward higher TCPO2 values up to one hour after treatment. This trend approached statistical significance. Heart rate, blood pressure, and respiratory rate all had a statis­tically significant increase after CPT but returned to pretreatment ranges within one hour.

Curran and Kachoyeanos compared using a pad­ded nipple for the percussion method with mechanical vibration using an electric toothbrush.45 They found significantly higher Pao2, better color, and clearer breath sounds in two infants who received vibration with the electric toothbrush than in two who received percussion with a padded nipple and two who re­ceived no CPT. The small number of subjects, how­ever, makes the results of this study questionable.

Vibration was the only manual technique used in two studies that evaluated the effects of CPT in neonates. Fox and associates used a mechanical vi­brator for 30 seconds over the anterior chest wall of infants in the supine position.46 Before the vibration, CDAP and supplemental oxygen were disconnected and 1.0 cc of saline was instilled into the trachea. The Pao2, Paco2, pH, airways resistance, lung compliance, and functional residual capacity were measured be­fore and after treatment. A decrease in Pao2 imme­diately following vibration and suctioning was noted. Hyperventilation of the neonates was postponed until after the posttreatment measurements, and, as in

other studies, the Pao2 returned to pretreatment range after hyperventilation. Airways resistance during ex­piration was decreased after CPT and suctioning but the Paco2, pH, lung compliance, and functional resid­ual capacity did not change significantly.

Finer and colleagues compared "routine" CPT— five minutes of vibration over the lung segment being drained—with no CPT.47 Subjects included neonates who had been intubated for 24 hours or more. The incidence of postextubation atelectasis was noted based upon chest radiograph evaluation. The group that received CPT had a significantly lower incidence of postextubation atelectasis and reintubation. The 42 subjects in this prospective study are a larger sample than in any other study reviewed here.

DISCUSSION

The results of the studies described were as varied as the techniques used, dependent variables mea­sured, and points at which they were measured. Major problems in determining the effects of CPT in neo­nates include: 1) lack of well-controlled studies 2) small number of subjects studied 3) differences in CPT techniques 4) lack of consensus on variables that indicate either

effectiveness or safety 5) difficulty in studying a homogeneous group of

subjects because of the many complications occur­ring in acutely ill neonates

6) disparity in experimental designs regarding the time at which dependent variables are measured

7) difficulty in measuring pulmonary function with­out highly technical or invasive procedures Although these problems are not all unique to

infants, they seem especially apparent in studies re­lated to neonatal CPT.

DIRECTIONS FOR FUTURE RESEARCH

Although CPT for neonates appears to be benefi­cial, well-designed and carefully controlled studies of larger numbers of infants are needed to justify fully and validate our treatments. Physical therapists, res­piratory therapists, and nurses who deliver neonatal care must increase their efforts to develop and docu­ment safe, effective techniques for treating these unique infants.

Accurate, workable operational definitions of CPT must be established. Strict definitions would not pre­clude comparing differing techniques, but would clar­ify what methods were used in treatment. Standard definitions would also provide direction to researchers not routinely involved in neonatal care. Research measuring the effects of CPT in neonates should include ET suctioning with hyperventilation and hy-peroxygenation as part of the treatment. This stand-

Volume 61 / Number 12, December 1981 1771

ardization will avoid biased results caused by differ­ent combinations of techniques used as treatment. Continuous monitoring of physiologic values may also help to eliminate the bias caused by collecting data on varied techniques and in different sequences.

Research in neonatal CPT requires larger numbers of subjects to improve the validity of studies. The diagnoses, stage of disease, gestational age at birth, and cardiopulmonary signs and symptoms must be more homogeneous in future studies. Collaboration among several NICU may help solve the problem of small numbers of subjects.

The merits of percussion versus vibration, and ad­vantages or disadvantages of bronchial drainage po­sitioning should receive further study. The manner of delivering percussion and vibration must be examined definitively. Are mechanical devices or manual tech­niques superior in administering percussion and vi­bration to neonates?

The long-term effects of CPT have not been ex­plored in any study discussed here, with the report by Finer and colleagues as a possible exception.47 Does CPT change rates of morbidity or mortality in neo­nates with pulmonary dysfunction? How long do the effects of treatment last? Also, there are little data by which to determine an optimal frequency of treat­ments.

These topics should be considered when planning research in neonatal CPT. The problems are not insurmountable. Pilot studies might help clinicians unaccustomed to working with infants. A pilot study can help perfect skills and increase knowledge, and permits evaluation of the research design. Most clin­ical research starts with a question, an idea, and a willingness to search systematically for an answer. Neonatal intensive care and its associated procedures are constantly developing. Physical therapists have an opportunity to be in the forefront of this exciting and challenging area of health care.

REFERENCES

1. Pringle ME, Kaminski SA, Raymond GL: Survey of physical therapy provided to infants under three months of age. Phys Ther 58:1055-1060, 1978

2. Lough MD, Williams TJ, Dawson JE (eds): Newborn Respi­ratory Care. Chicago, IL, Year Book Medical Publishers, Inc, 1979, pp 150-152

3. Scarpelli EM, Auld PA, Goldman HS (eds): Pulmonary Dis­ease of the Fetus, Newborn and Child. Philadelphia, PA, Lea & Febiger, 1978, chaps 3, 6, 12, 14, 16

4. Petty TL: Intensive and Rehabilitative Respiratory Care: A Practical Approach to the Management of Acute and Chronic Respiratory Failure, ed 2. Philadelphia, PA, Lea & Febiger, 1974, p 2 7 9

5. Wallis S, Harvey D: Respiratory distress: Its cause and man­agement. Nursing Times 75:1264-1272, 1979

6. Lindroth M, Svenningsen NW, Ahlstrom H, et al: Evaluation of mechanical ventilation in newborn infants: 1. Techniques and survival rates. Acta Paediatr Scand 69:143-149, 1980

7. Dunn D, Lewis AT: Some important aspects of neonatal nursing related to pulmonary disease and family involvement. Pediatr Clin North Am 20(2):481-498, 1973

8. Daily WJR, Smith PC: Mechanical ventilation of the newborn infant: Part II. Curr Probl Pediatr 1(9):3-13, 1971

9. Laitman JT, Crelin ES: Developmental change in the upper respiratory system of human infants. Perinat/Neonat 4:15-21, 1980

10. Kattan M: Long-term sequelae of respiratory illness in infancy and childhood. Pediatr Clin North Am 26(3):525-535, 1979

11. Gerhardt T, Bancalari E: Chestwall compliance in full-term and premature infants. Acta Paediatr Scand 69:359-364, 1980

12. Hunt CE: The high risk newborn. Minn Med 57(5):405-412, 1974

13. Farrell PM, Avery ME: Hyaline membrane disease: State of the art. Am Rev Respir Dis 3:657-688, 1975

14. Frownfelter DL (ed): Chest Physical Therapy and Pulmonary Rehabilitation. Chicago, IL, Year Book Medical Publishers, Inc, 1978, pp 371-372

15. Gregory GA, Thibeault DW (eds): Neonatal Pulmonary Care. Reading, MA, Addison-Wesley Publishing Co, 1979, pp 6 5 -66

16. Northway WH, Rosan RC, Porter DY: Pulmonary disease following respirator therapy of hyaline membrane disease. N Engl J Med 275:357-368, 1967

17. Wesenberg RL: The Newborn Chest. Baltimore, MD, Harper & Row, Publishers, Inc, 1973, p 62

18. Mikity VG, Taber P: Complications in the treatment of respi­ratory distress syndrome. Pediatr Clin North Am 20(2):419-431, 1973

19. Bacsik RD: Meconium aspiration syndrome. Pediatr Clin North Am 24(3):463-479, 1977

20. Sun SC, Samuels S, Verasestakul S, et al: Meconium aspi­ration and tracheal suction. J Med Soc NJ 74(6):542-545, 1977

21. Northway WH, Rosan RC, Porter DY: Pulmonary disease following respirator therapy of hyaline membrane disease: Bronchopulmonary dysplasia. N Engl J Med 276:357-367, 1967

22. Watts JL, Ariagno RL, Brady JP: Chronic pulmonary disease in neonates after artificial ventilation: Distribution of ventila­tion and pulmonary interstitial emphysema. Pediatrics 60: 2 7 3 - 2 8 1 , 1 9 7 7

23. Kotlmeier PK, Klotz D: Surgical problems in the newborn. Pediatr Ann 8:60-81, 1979

24. Jacob J, Edwards D, Gluck L: Early onset sepsis and pneu­monia observed as respiratory distress syndrome. Am J Dis Child 134:766-768, 1980

25. Graham WGB, Bradley DA: Efficacy of chest physiotherapy and intermittent positive-pressure breathing in the resolution of pneumonia. N Engl J Med 299:624-627, 1978

26. Rochester DF, Goldberg SK: Techniques of respiratory phys­ical therapy. Am Rev Respir Dis 122(5): 133-146, 1980

27. Rudolph AM: High pulmonary vascular resistance after birth: 1. Pathophysiologic considerations and etiologic classifica­tion. Clin Pediatr 19(9):585-590, 1980

28. Nagaraj HS, Shott R, Fellows R, et al: Recurrent lobar atel­ectasis due to acquired bronchial stenosis in neonates. J Pediatr Surg 15(4):411 -415 , 1980

29. Fawcett WA, Gluck L: Respiratory distress syndrome in the tiny baby. Clin Perinatol 4(2):411-423, 1977

30. Babson SG, Benson RC, Pernoll ML, et al: Management of High-Risk Pregnancy and Intensive Care of the Neonate. St Louis, MO, C.V. Mosby Co, 1975, p 224

31. Scarpelli EM (ed): Pulmonary Physiology of the Fetus, New­born and Child. Philadelphia, PA, Lea & Febiger, 1975, p 157

32. Speidel BD: Adverse effects of routine procedures on pre­term infants. Lancet 1.864-866, 1978

33. Finer NN, Boyd J: Chest physiotherapy in the neonate: A controlled study. Pediatrics 61:282-285, 1978

1772 PHYSICAL THERAPY

34. Huch R, Huch A, Albani M, et al: Transcutaneous Po2 moni­toring in routine management of infants and children with cardiorespiratory problems. Pediatrics 57:681-690, 1976

35. Freedman RM, Abassis, Matthews TG, et al: Transcutaneous carbon dioxide monitoring in neonates, abstracted. Pediatr Res 12:597, 1978

36. Young IM, Holland WW: Some physiological responses of neonatal arterial blood pressure and pulse rate. Br Med J 2: 276-278, 1958

37. Moss AJ, Duffie ER, Emmanovilides G: Blood pressure and vasomotor reflexes in the newborn infant. Pediatrics 32:176-179, 1963

38. Crane LD, Zombek M, Krauss AN, et al: Comparison of chest physiotherapy techniques in infants with HMD, abstracted. Pediatr Res 12(4):559, 1978

39. Zack MB, Pontoppidan H, Kazemi H: The effect of lateral positions on gas exchange in pulmonary disease. Am Rev Respir Dis 110:49-54, 1974

40. Mellins RB: Pulmonary physiotherapy in the pediatric age group. Am Rev Respir Dis 110:137-142, 1974

4 1 . Menkes H, Britt J: Physical therapy: Rationale for physical therapy. Am Rev Respir Dis 122(5): 127-131, 1980

42. Holloway R, Adams EB, Desai SD, et al: Effect of chest physiotherapy on blood gases of neonates treated by inter­mittent positive-pressure respiration. Thorax 24:421-426, 1969

43. Raval D, Yeh TF, Mora A, et al: Changes in transcutaneous Po2 during tracheobronchial hygiene in neonates. Perinat/ Neonatal 4:41-45, 1980

44. Etches PC, Scott B: Chest physiotherapy in the newborn: Effect on secretions removed. Pediatrics 62:713-715,1978

45. Curran CL, Kachoyeanos MK: The effects on neonates of two methods of chest physical therapy. Matern Child Nurs J 4:309-313, 1979

46. Fox WW, Schwartz JG, Shaffer TH: Pulmonary physiotherapy in neonates: Physiologic changes and respiratory manage­ment. J Pediatr 92:977-981, 1978

47. Finer NN, Moriartey RR, Boyd J, et al: Post-extubation atel­ectasis: A retrospective review and a prospective study. J Pediatr 94:110-113, 1979

NEONATAL CPT QUIZ

1. Insufficient levels of surfactant in the lung may be re­sponsible for neonatal respiratory distress in a. bronchopulmonary dysplasia. b. idiopathic respiratory distress syndrome. c. meconium aspiration syndrome. d. transient tachypnea of the newborn. e. All of the above.

2. Auscultation of the chest is not a very sensitive evaluative tool in the tiny neonate because a. neonates normally have decreased breath sounds. b. increased chest wall compliance of the neonate con­

tributes to adventitious breath sounds. c. breath sounds and adventitious sounds are easily

transmitted throughout the thorax in a neonate. d. a and c above. e. None of the above.

3. The CPT treatment of a neonate a. should always include both percussion and vibration

manual techniques during bronchial drainage maneu­vers.

b. is appropriate for neonates with documented diag­noses of hyaline membrane disease.

c. should always include airway suctioning. d. should include modified positioning whenever possi­

ble. e. None of the above.

Answers

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