Postoperative apnea in former preterm infants: prospective comparison of spinal and general anesthesia. High-dose caffeine suppresses postoperative apnea in former preterm infants. Efficacy of nasal intermittent positive pressure ventilation in treating apnea of prematurity. Reduction of sleep apnea and bradycardia in preterm infants on oscillating water beds: a controlled polygraphic study. Post-operative recovery after inguinal herniotomy in ex-premature infants: comparison between sevoflurane and spinal anaesthesia. Postoperative apnea, bradycardia, and oxygen desaturation in formerly premature infants: prospective comparison of spinal and general anesthesia. The effect of vertical pulsating stimulation on apnea of prematurity. Does supine positioning increase apnea, bradycardia, and desaturation in preterm infants? Effect of positioning on the breathing pattern of preterm infants.
Thirty-six former preterm infants undergoing inguinal hernia repair were studied. All were less than or equal to 51 weeks postconceptual age at the time of operation. Patients were randomly assigned to receive general or spinal anesthesia. Group 1 patients received general inhalational anesthesia with neuromuscular blockade. Group 2 patients received spinal anesthesia using 1% tetracaine 0.4-0.6 mg/kg in conjunction with an equal volume of 10% dextrose and 0.02 ml epinephrine 1:1000. In the first part of the study, infants randomized to receive spinal anesthesia also received sedation with im ketamine 1-2 mg/kg prior to placement of the spinal anesthetic (group 2 A). The remainder of group 2 patients did not receive sedation (group 2 B). Respiratory pattern and heart rate were monitored using an impedance pneumograph for at least 12 h postoperatively. Tracings were analyzed for evidence of apnea, periodic breathing and/or bradycardia by a pulmonologist unaware of the anesthetic technique utilized. None of the patients who received spinal anesthesia without ketamine sedation developed postoperative bradycardia, prolonged apnea, or periodic breathing. Eight of nine infants (89%) who received spinal anesthesia and adjunct intraoperative sedation with ketamine developed prolonged apnea with bradycardia. Two of the eight infants had no prior history of apnea. Five of the 16 patients (31%) who received general anesthesia developed prolonged apnea with bradycardia. Two of these five infants had no prior history of apnea. When infants with no prior history of apnea were analyzed separately, there was no statistically significant increased incidence of apnea in children receiving general versus spinal anesthesia with or without ketamine sedation. Because of the small numbers of patients studied, and the multiple factors that may influence the incidence of postoperative apnea (e.g., prior history of neonatal apnea), standard postoperative respiratory monitoring of these high-risk infants is still recommended following all anesthetic techniques. Thirty-two former preterm infants (less than or equal to 44 weeks postconceptual age) undergoing inguinal hernia repair were prospectively studied. General inhalational anesthesia with neuromuscular blockade was used. No barbiturates or opioids were given. Infants were randomly divided into two groups. Group 1 received iv caffeine 10 mg/kg immediately after induction of anesthesia. Group 2 received iv saline. Respiratory pattern, heart rate, and SpO2 were monitored using an impedance pneumograph and a pulse oximeter, respectively, for at least 12 h postoperatively. Tracings were analyzed for evidence of apnea, periodic breathing, and/or bradycardia by a pulmonologist unaware of the drug given. None of the patients who received caffeine developed postoperative bradycardia, prolonged apnea, or periodic breathing, and none had postoperative SpO2 less than 90%. In the control group 13 (81%) developed prolonged apnea 4-6 h postoperatively. Fifty percent of the patients had SpO2 less than 90% at the time. This study shows that iv caffeine 10 mg/kg is effective in the control of apnea in otherwise healthy expremature infants between 37 and 44 weeks of postconceptual age. It is still recommended, however, that all infants at risk be monitored for at least 12 h for apnea and bradycardia following general anesthesia. The efficacy of nasal intermittent positive pressure ventilation (NIPPV) in treating apnea of prematurity was evaluated. Apneic preterm infants were randomly assigned to receive either NIPPV or continuous positive airway pressure (NCPAP) for 4 hr when they failed to respond to conservative therapy. The amount of reduction in apneic spells and bradycardia in the two groups after treatment was compared. Thirty-four infants (18 with NIPPV, 16 with NCPAP) were enrolled. Their birth weights ranged from 590-1,880 g (mean, 1,021 g) and gestational ages from 25-32 weeks (mean, 27.6 weeks). The baseline characteristics were comparable in the two groups. Frequency of apnea and bradycardia was reduced during both forms of treatments. However, the infants receiving NIPPV had a greater reduction of apneic spells (P = 0.02) and a tendency to greater decrease in bradycardia (P = 0.09) than those receiving NCPAP. We conclude that NIPPV is more effective than NCPAP in reducing apnea in preterm infants. NIPPV may reduce bradycardia; however, this needs to be validated by a larger number of observations. The sleep and respiratory patterns of eight apneic preterm infants were polygraphically recorded for 24 hours. This polygraphic study was designed to test and extend our previous finding that gently oscillating water beds reduce apnea in premature infants. The infants who ranged in gestational age from 27 to 32 weeks and in birth weight from 1,077 to 1,650 gm served as their own controls, off and on the water bed. The 24-hour recordings were divided into four time blocks with the infant being placed on the water bed during alternate six-hour periods. Apnea was significantly reduced while the infants were on the oscillating water beds, with the longest apneic periods and those associated with severe bradycardia being reduced the most. Reduction of apnea was most consistent during indeterminate sleep and most pronounced during quiet sleep. Short respiratory pauses and periodic breathing were not significantly reduced. Reductions of central, obstructive, and mixed apneas were approximately equal. We prospectively studied the post-operative recovery profile of 28 ex-premature infants undergoing inguinal herniotomy. All infants had a post-conceptual age of less than 46 weeks at the time of surgery and were randomized to receive either sevoflurane (group 1, 14 patients) or spinal anaesthesia (group 2, 14 patients). All patients received supplemental caudal analgesia before skin incision. Cardiorespiratory function was continuously recorded in all patients before and after surgery. A blinded observer analysed each paired recording for predefined episodes of apnoea, hypoxaemia or bradycardia and the reports were used to compare the two groups. Spinal anaesthesia was attempted unsuccessfully in four patients in group 2. Five patients in group 1 demonstrated an 'excess' number of episodes (median 4, range 3-12) of clinically silent post-operative cardiorespiratory complications. ('Excess' in our study was defined as a 3-fold or greater increase in the number of post-operative episodes of bradycardia or apnoea relative to pre-operative occurrence). Three of these patients had pre-existing abnormal respiratory function and accounted for 80% of the episodes (26/32) of post-operative bradycardia and all five episodes of post-operative apnoea identified. All episodes of bradycardia and apnoea were temporally unrelated. None of the remaining patients in group 2 demonstrated an unacceptable number of post-operative cardiorespiratory complications. Our limited study suggests that general anaesthesia with an inhalational agent such as sevoflurane may induce or unmask abnormalities of cardiopulmonary function in predisposed infants. Spinal anaesthesia may be preferable but it is potentially stressful for the infant and associated with a clinically significant failure rate. Eighteen formerly premature infants scheduled for inguinal herniorrhaphy and who were less than 51 wk postconceptional age were assigned to either the general anesthesia group (GA: atropine, halothane, and nitrous oxide) or the spinal anesthesia group (SA: hyperbaric tetracaine). Twelve-hour, three-channel continuous recordings of respiratory rate (chest wall impedance), electrocardiogram (ECG), and hemoglobin O2 saturation (SpO2) were obtained preoperatively and after surgery. These were analyzed for short (11-15s) and long (> 15 s) apnea spells, periodic breathing, and episodes of hemoglobin oxygen desaturation and bradycardia. Infants in the GA group had lower postoperative minimum SpO2 (68.7% +/- 11.4%) and minimum heart rate (79 bpm +/- 19) than infants in the SA group (80.7% +/- 9.2%, and 109 bpm +/- 30, respectively; P < 0.05) and had lower postoperative minimum SpO2 and minimum heart rate than they had preoperatively (79.0% +/- 13.7%, and 93 bpm +/- 31, respectively; P < 0.05); pre- and postoperative studies in the SA group did not differ. There were no differences in the incidence of postoperative central apnea. We conclude that spinal anesthesia reduces postoperative hemoglobin oxygen desaturation and bradycardia in formerly premature infants undergoing inguinal herniorrhaphy. Placing preterm infants suffering idiopathic apnea of prematurity on the VPS had an effect on the infants' respiratory effort and achieved a reduction in the number of apneic episodes secondary to central and mixed apnea. However, VPS offered no benefits in the reduction of obstructive apnea in this study population. Because central apnea has been reported as the predominant type of apnea and VPS is a nontoxic, noninvasive, and easy-to-implement method of alleviating central and mixed apnea types, it seems prudent to give VPS which has the stimulus characteristics to preterm infants experiencing apnea of prematurity before other treatment modalities currently in use are tried. Further studies are warranted to determine if VPS is effective in a continuous long-term treatment for apnea of prematurity, for example, until the end of apnea. The purpose of this study was to determine the effects of prone and supine positioning on the cardiorespiratory stability of preterm infants with apnea and bradycardia.
                A total of 22 preterm infants with symptomatic apnea and bradycardia (gestational age of 26.9 +/- 1.8 weeks and birth weight of 865 +/- 235 gm) were monitored for 24 hours (in four sequential 6-hour blocks) for apnea, bradycardia, and oxygen desaturation in alternating positions (prone or supine) following randomization. Postconceptional age at the time of study was 31.9 +/- 3.0 weeks. Respiratory rate, heart rate, and transcutaneous oxygen saturation were continuously monitored. All episodes of apnea (> or = 10 seconds), bradycardia (< 100 beats per minute), and oxygen desaturation (< 90%) were recorded on an event monitor. Episodes of apnea, bradycardia, and oxygen desaturation were defined as clinically significant if the following criteria were met: apnea, > or = 15 seconds; bradycardia, < 90 beats per minute; and oxygen desaturation, < 80%. All other recorded episodes were considered mild. The episodes were analyzed for statistical significance using the paired t-test.
                No significant differences (p > 0.05) in the incidence of clinically significant apnea, bradycardia, or desaturation between supine and prone positions were seen in these preterm infants.
                Our results suggest that the cardiorespiratory stability of preterm infants is not significantly compromised by supine positioning. Respiration, as judged by gas exchange and pulmonary function, is improved in preterm infants kept in the prone rather than the supine position. The influence of position on the breathing pattern as documented by the pneumogram was studied in 14 stable preterm infants with recent clinical apnoea. Ten of the infants had oximetry and nasal flow studies simultaneously with the impedance pneumogram. Each infant had consecutive nocturnal pneumograms, one in the prone, one in the supine position. The infants were kept for more than six hours in the assigned position. A significant increase in apnoea density and in periodic breathing was found in the supine v the prone position (mean (SE) 4.5 (0.7)% v 2.5 (0.5)%, and 13.6 (3.2)% v 7.7 (2.2)%, respectively). There was no positional difference in the incidence of bradycardia and prolonged apnoea. The examination of obstructive apnoea, mixed apnoea, and cyanotic spells did not reveal a consistent disparity between the two positions. These findings indicate an increase in central apnoea in preterm infants kept predominantly in the supine position. Possible relations of positional changes to lung mechanics are discussed. When evaluating pneumograms, attention must be given to the position in which they were performed.
Implications for practice. Prophylactic use of kinesthetic stimulation cannot be recommended to reduce apnea/bradycardia in preterm infants.
Implications for research. There are currently no clear research questions regarding prophylactic use of kinesthetic stimulation to prevent apnea in preterm infants.