AMERICAN JOURNAL OF DISEASES OF THE CHILD, Volume 134, Number 7: Pages 676-678,
July 1980.

The Effect of Circumcision
on Transcutaneous PO2 in Term Infants.

David J Rawlings, MD; Patricia Anne Miller; Rolf R Engel, MD

      * To assess the effect of pain on PaO2 in newborns, transcutaneous PO2 (tcPO2) was monitored in ten healthy male infants undergoing circumcision. The tcPO2 was seen to decrease to a lower level with pain and to remain low with continuing pain. After the circumcision, the tcPO2 increased to levels equal to or exceeding those of the preoperative baseline period. Close concordance of tcPO2 above and below the waist demonstrated no right-to-left shunting through the ductus arteriosus.

      (Am J Dis Child 134:676-678, 1980)


Investigators1-5 who have correlated Pao2 with transcutaneous Po2 (tcPo2) have obtained blood samples from indwelling arterial lines because of concern that the pain of an arterial puncture may disturb oxygenation. To further define the effect of pain on tcPo2, normal male infants were monitored during circumcision. Simultaneous monitoring of the tcPo2 over the right upper side of the chest and left lower part of the abdomen enabled us to evaluate the possibility of right-to-left shunting through the ductus arteriosus during the procedure of circumcision.


       Ten healthy male infants were circumcised at 48 to 72 hours of age after obtaining informed consent from the parents. All were born at term with one-minute Apgar scores greater than 7 and a mean birth weight of 3,350 g. Neither heart murmurs nor abnormal femoral artery pulses were detected immediately prior to circumcision.

       The procedure consisted of the following: about five minutes of cleaning the penis with povidone-iodine (Betadine) solution; adhesion lysis between glans and foreskin; dorsal foreskin clamping with forceps for two to four minutes followed by forceps removal and division of the crushed skin. A bloodless circumcision clamp (Gomco) was applied for five minutes before the foreskin was amputated. To discern the effect for each of the four painful manipulations, the interval from adhesion lysis to circumcision clamp removal was extended to 20 minutes.

       Throughout the study, a radiant overhead warmer was used to maintain the abdominal skin temperature at 36.0°C. A nipple was offered for nonnutritive sucking. The period of continuous monitoring included at least 20 minutes before and after the circumcision. Transcutaneous oxygen electrodes (TCM1 Radiometer) were affixed below the right clavicle and to the left of the umbilicus. Both electrodes were thermally insulated with expanded rigid polystyrene plastic caps so that the electrode heat consumption served as an indirect measure of local blood flow.6 Respiratory and heart rates were monitored with vital signs modules. All parameters were recorded continuously on a potentiometric recorder. The tcPo2 electrodes were interchanged at the end of the monitoring periods to help separate instrumentation from physiologic differences. Average values were obtained from planimetry of the tracings.7 Statistical comparisions used two-tailed τ testing.


       Each of the studies demonstrated close concordance between the tcPo2 tracings from the chest and abdomen (Fig 1). None of the infants showed a significant difference between chest and abdominal tcPo2 during the quiet or crying intervals. Both tcPo2 tracings decreased with pain and remained at a lower level until crying ceased. During brief respites from crying, the tcPo2 was often exceeded.

Figure one

Fig 1.-Continuous recording of transcutaneous Po2 (tcPo2) on chest and abdomen during circumcision. Abdominal tracting was shifted down 8 mm Hg for clarity.

       The change in tcPo2 after the four painful procedures involved in circumcision was plotted for each of the ten subjects (Fig 2). There was a significant decrease in tcPo2 for all 40 events considered together. (P<.001) and for three of the four individual categories. The average decrease in the tcPo2 was 15 mm Hg for adhesion lysis, less than 1 mm. for foreskin clamping, 13 mm Hg for circumcision clamp application, and 19 mm Hg for circumcision clamp removal. The negligible response to foreskin clamping probably reflects the absence of a quiet interval before this event in contrast to adhesion lysis and circumcision clamp removal, both of which followed manipulation-free intervals of five or more minutes, and circumcision clamp application, which was preceded by variable freedom from stimulation. The average postevent tcPo2 for each of the four manipulations was not significantly different than that for any of the other three.

Figure 2

Fig2.-Chest transcutaneous Po2 (tcPo2) immediately before and maximum change within two minutes after onset of painful events for ten infants.

       The average tcPo2 was increased during the postoperative period. (P<.05, Table.).


       Circumcision in neonates has been shown to affect adrenal cortical functions,8 immediate postoperative behavior and possibly long-term behavior.12 The present study demonstrates that circumcision also affects the heart rate, respiratory rate, and tcPo2 both during and immediately after the procedure. The observed decrease in tcPo2 with pain might result from momentary decreases in alveolar ventilation during crying. Right-to-left shunting at the atrial level, with crying, as shown by Lind et al13 during the first two weeks of life, is also a possible explanation. The close concordance of chest and abdominal tcPo2 indicates that despite vigorous crying right-to-left shunting through the ductus arteriosus did not occur in our sample of 2- to 3-day-old, term male infants. The absence of hypoxic symptoms in this group of term infants is in accord with our prediction that healthy infants should not be compromised by a transient decrease of 20 mm Hg in tcPo2.

 HEART RATE, Respiratory Rate and tcP2 at Circumcision
                           Operative Periods         
                                Before      During     After
Heart rate, beats/min 
Mean                              122         165*      138+
SD                                 26          21        28
Range                            99-174     139-197    98-180

Repiratory rate, breaths/min       
Mean                                43         50+       53+    
SD                                  12         11        12
Range                             22-64       39-77    40-79

Mean                               75          82        85+  
SD                                  8          17        12
Range                            62-88       66-129    65-106 
*TcPo2 indicates transcutaneous Po3, which was measured below right clavicle.
+Significantly (P<.05) greater than preoperative value.

       The 10 mm Hg decrease in mean tcPo2 after the circumcision could reflect increased minute ventilation in lungs fully expanded from recent crying. Although Martin et al5 have also observed meant tcPo2 less than 80 mm Hg in healthy infants, it is possible that an allowance should be made for the thicker skin of term infants since the electrode temperature of 44°C and the warm-up period of 20 minutes were based on correlation (r =.95) between the tcPo2 and Pao2 in premature infants.

       The response to pain by each individual infant was surprisingly consistent. That is, some infants had abrupt decreases in tcPo2 and increases in heart and respiratory rates with each of the painful stimuli while other infants repeatedly had attenuated responses. These individual variations in the response to pain underline the limited reliability of arterial punctures for assessment of resting Pao2. Since the tcPo2 often exceeded baseline values after crying ceased, there is also the possibility that delay in drawing an arterial blood sample could result in obtaining a Pao2 that is greater than the baseline.


       1. Krauss AN, Waldman S, Frayer WW, et al: Noninvasive estimation of arterial oxygen in newborn infants. J Pediatr 93:275-278, 1978.
         2. Friss-Hansen B, Marstand-Christiansen P, Vesterager P: Transcutaneous measurement of arterial blood oxygen tension with a new electrode. Scand J Clin Lab Invest 37 (suppl 146):31-36, 1977.
         3.Okken A, Rubin IL, Martin RJ: Intermittent bag ventilation of preterm infants on continuous positive airway pressure: The effect on transcutaneous Po2. J Pediatr 93:279-282, 1978.
         4. 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.
         5. Martin RB, Okken A, Rubin D: Arterial oxygen tension during active and quiet sleep in the normal neonate. J Pediatr 94:271-274, 1979
         6. Peabody JL, Willis MM, Gregory GA, et al: Reliability of skin (tc) Po2 electrode heating power as a continuous noninvasive monitor of mean arterial pressure in sick newborns. Birth Defects 15:127-133, 1979.
         7. Yang SS, Bentivoglio LG, Maranhao V, et al: From Cardiac Catherization to Hemodynamic Parameters, ed 2. Philadelphia, FA Davis Co, 1978, pp 51-54.
         8. Talbert LM, Kraybill EN, Potter DH: Adrenal cortical response to circumcision in the neonate. Obstet Gynecol 48:208-210, 1976
         9. Anders TF, Chalemian RJ: The effects of circumcision on sleep-wake states in human neonates. Psychosom Med 36:174-179, 1974.
       10. Emde RN, Harmon RJ, Metcalf D, et al: Stress and neonatal sleep. Psychosom Med 33:491-497, 1971.
       11. Marshall PE, Stratton WC, Moore JA, et al: Circumcision: Effects upon newborn behavior: A controlled blind study. Pediatr Res 12:334, 1979.
       12. Richards MP, Bernal JF, Brackbill Y: Early behavioral differences: Gender or circumcision? Dev Psychobiol 9:89-95, 1976.
       13. Lind J, Stern L, Wegelius C: Human Foetal and Neonatal Circulation. Springfield, Ill, Charles C Thomas Publisher, 1964.

       From the Department of Pediatrics, University of Michigan Medical School, Minneapolis, (Drs Rawlings and Engel); and Hennepin County Medical Center, Minneapolis (Drs Rawlings, Engel, and Ms Miller).

       Reprint requests to Hennepin County Medical Center, 701 Park Ave S, Minneapolis, MN 55415 (Dr Engel).

(File revised 20 May 2005)

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