ANESTHESIA A N D ANALGESIA . . . Current Researches VOL.55. No. 4. JULY-AUGUST, 1976
592
ROBERT K. STOELTING Associate Editors
Prevention of Hy pothermia During Cystoscopy in Neonates MICHAEL B. MEYERS, M D * TAE H. OH, M D t
New Haven, Connecticuti
P
of intraoperative temperature control in the neonate are well documented. Use of warming blankets, overhead warming lights, humidified warm gases, heated IV fluids, and warm fluid-filled gloves have facilitated better temperature control. However, such modalities are not always adequate.' The following report presents a n additional method of temperature control during neonate cystoscopy, during which irrigation of the bladder may result in hazardous hypothermia.
ful awake tracheal intubation, halothane, N,O, and 0, were administered with a nonrebreathing system. Despite the use of a warming blanket, overhead warming lights, and warm humidified gases, tympanic membrane temperature showed a precipitous fall a t the beginning of cystoscopy, using continuous bladder irrigation with sterile, 23.5" C, water. At a temperature of below 35" C, the procedure was abandoned and he was returned to the recovery room, with a temperature of 34.5" C.
REPORT OF A CASE A 10-week-old, 2.8 kg Caucasian infant was admitted with anemia and E. coli sepsis secondary to obstructive uropathy. As diagnostic workup revealed posterior urethral valves, he was scheduled for cystoscopy and fulguration. Preoperatively, the patient was given 0.1 mg of atropine IV and brought to the cystoscopy suite. Following an unevent-
Seven days later, the infant was again taken to the cystoscopy suite for cystoscopy and perineal urethroplasty. After awake tracheal intubation, anesthesia was induced with halothane-N,O-0, via a nonrebreathing system. Temperature was controlled with radiant heat lights and a warming blanket and mattress, but the lithotomy position made possible only minimal contact
ROBLEMS
':'Residentof Anesthesiology, ?Assistant Professor of Anesthesiology. XDepartment of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06510. Reprint requests to Dr. Oh. Paper received: 12/1/75 Accepted for publication: 1/23/76
593
Brief Reports . . .
with the warming mattress. Tympanic temperature, which was 38" C during the induction of anesthesia, once again began to fall at the beginning of continuous bladder irrigation. After 30 minutes, the temperature had decreased to 35" C. A t this point, a standard blood-warming coil was interposed between the bladder irrigation system and the cystoscope and immersed in a water bath maintained at 40" C. The cystoscopy with urethroplasty continued for an additional 20 minutes. Anesthesia was completed without incidence, and in the rrcovery room, the infant's temperature was 35.8" C. DISCUSSION The temperature Of the newborn undergoing cystoscopy in the lithotomy position is often compromised by the use of n cool solution room temperature) for the continuous irrigation of a core compartment. The body mass of the neonat(> is approximately 5551, that of the adult, while body surface area is only 157;,. Therefore, there is a greater capacity for heat dissipation. The neonate also lacks the subcutaneous fat and tissue of the adult.
greater heat loss over a shorter period of timc.3.4 Most anesthetic agents contribute to hypothermia by reducing afferent stimuli, preventing shivering and muscular activity, inhibiting metabolism, and causing cutaneous vasodilation. Inadvertent hypothermia is one cause of neonatal morbidity and mortalit^.^ Continuous irrigation of a highly vascular core compartment with a warm aqueous solution may facilitate maintenance of a normal body temperature when used from the start of neonate cystoscopy. REFERENCES 1. S h i m WKT. Halford P: Method for maintaining the neonate's intraoperative rove temperature. S U ~ ~ C 75:416-420, ~ V 1974 2. Motil KJ. Blackburn M G : Temperature regulation in the neonate: a survey of pathophysiology of thermal dynamics a n d of t h e prinriples of rnvironmcntal rontrol. Clin Pediatr 12:634-639, 1973 3 . 13rG& K: ~ ~ regulation in ~ the new. horn infant. BioI Neonate 3:65-119. 1961
4. Adamsons K J r , Towell MF:: Therl,,al holmeostasis in the fetlls anct newb01.n. Anesthesiologv 2f;: 5 3 - 5 4 8 . 1965
Estimation of Anesthetic Solubility in Blood ALFRED FEINGOLD, MS, MD*
P
of inhalation anesthetics classically describe the blood/gas partition coefficient ( B / G ) as an important determinant of the speed of induction of and emergence from inhalation anesthesia. For this reason, the solubility in blood has been determined for virtually all anesthetics. HARMACOKINETICS
This blood solubility may be divided into 3 major components: solubility in lipids, water, and plasma proteins.'-4 Featherstone's group' and Lowe? have reasoned that B/G
may be estimated by addition of 0.8 times the water/gas partition coefficient ( W / G ) and 0.005 times the fat/gas partition coefficient ( F / G ) . These coefficients correspond to the water and lipid content of normal blood and result in the equation: (1) B/G = 0.8 W/G + 0.005 F / G The application of this formula, however, ; Ilose-regulated Penthraneq Anesthesia, Abbott Lab-
oratories. North Chirago, Illinois.
"Assistant Professor, Department of Anesthesiology, IJniversity of M i a m i School of Medicine. a n d Veterans Administration Hospital, Miami, Florida 33152. T h i s study was supported in p a r t by N I H G r a n t #GM l(i198 a n d funds from t h e Miami Veterans Administration Hospital. Paper received: 9/2/75 Accepted for publication: 1/22/76
,
~
592
ROBERT K. STOELTING Associate Editors
Prevention of Hy pothermia During Cystoscopy in Neonates MICHAEL B. MEYERS, M D * TAE H. OH, M D t
New Haven, Connecticuti
P
of intraoperative temperature control in the neonate are well documented. Use of warming blankets, overhead warming lights, humidified warm gases, heated IV fluids, and warm fluid-filled gloves have facilitated better temperature control. However, such modalities are not always adequate.' The following report presents a n additional method of temperature control during neonate cystoscopy, during which irrigation of the bladder may result in hazardous hypothermia.
ful awake tracheal intubation, halothane, N,O, and 0, were administered with a nonrebreathing system. Despite the use of a warming blanket, overhead warming lights, and warm humidified gases, tympanic membrane temperature showed a precipitous fall a t the beginning of cystoscopy, using continuous bladder irrigation with sterile, 23.5" C, water. At a temperature of below 35" C, the procedure was abandoned and he was returned to the recovery room, with a temperature of 34.5" C.
REPORT OF A CASE A 10-week-old, 2.8 kg Caucasian infant was admitted with anemia and E. coli sepsis secondary to obstructive uropathy. As diagnostic workup revealed posterior urethral valves, he was scheduled for cystoscopy and fulguration. Preoperatively, the patient was given 0.1 mg of atropine IV and brought to the cystoscopy suite. Following an unevent-
Seven days later, the infant was again taken to the cystoscopy suite for cystoscopy and perineal urethroplasty. After awake tracheal intubation, anesthesia was induced with halothane-N,O-0, via a nonrebreathing system. Temperature was controlled with radiant heat lights and a warming blanket and mattress, but the lithotomy position made possible only minimal contact
ROBLEMS
':'Residentof Anesthesiology, ?Assistant Professor of Anesthesiology. XDepartment of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06510. Reprint requests to Dr. Oh. Paper received: 12/1/75 Accepted for publication: 1/23/76
593
Brief Reports . . .
with the warming mattress. Tympanic temperature, which was 38" C during the induction of anesthesia, once again began to fall at the beginning of continuous bladder irrigation. After 30 minutes, the temperature had decreased to 35" C. A t this point, a standard blood-warming coil was interposed between the bladder irrigation system and the cystoscope and immersed in a water bath maintained at 40" C. The cystoscopy with urethroplasty continued for an additional 20 minutes. Anesthesia was completed without incidence, and in the rrcovery room, the infant's temperature was 35.8" C. DISCUSSION The temperature Of the newborn undergoing cystoscopy in the lithotomy position is often compromised by the use of n cool solution room temperature) for the continuous irrigation of a core compartment. The body mass of the neonat(> is approximately 5551, that of the adult, while body surface area is only 157;,. Therefore, there is a greater capacity for heat dissipation. The neonate also lacks the subcutaneous fat and tissue of the adult.
greater heat loss over a shorter period of timc.3.4 Most anesthetic agents contribute to hypothermia by reducing afferent stimuli, preventing shivering and muscular activity, inhibiting metabolism, and causing cutaneous vasodilation. Inadvertent hypothermia is one cause of neonatal morbidity and mortalit^.^ Continuous irrigation of a highly vascular core compartment with a warm aqueous solution may facilitate maintenance of a normal body temperature when used from the start of neonate cystoscopy. REFERENCES 1. S h i m WKT. Halford P: Method for maintaining the neonate's intraoperative rove temperature. S U ~ ~ C 75:416-420, ~ V 1974 2. Motil KJ. Blackburn M G : Temperature regulation in the neonate: a survey of pathophysiology of thermal dynamics a n d of t h e prinriples of rnvironmcntal rontrol. Clin Pediatr 12:634-639, 1973 3 . 13rG& K: ~ ~ regulation in ~ the new. horn infant. BioI Neonate 3:65-119. 1961
4. Adamsons K J r , Towell MF:: Therl,,al holmeostasis in the fetlls anct newb01.n. Anesthesiologv 2f;: 5 3 - 5 4 8 . 1965
Estimation of Anesthetic Solubility in Blood ALFRED FEINGOLD, MS, MD*
P
of inhalation anesthetics classically describe the blood/gas partition coefficient ( B / G ) as an important determinant of the speed of induction of and emergence from inhalation anesthesia. For this reason, the solubility in blood has been determined for virtually all anesthetics. HARMACOKINETICS
This blood solubility may be divided into 3 major components: solubility in lipids, water, and plasma proteins.'-4 Featherstone's group' and Lowe? have reasoned that B/G
may be estimated by addition of 0.8 times the water/gas partition coefficient ( W / G ) and 0.005 times the fat/gas partition coefficient ( F / G ) . These coefficients correspond to the water and lipid content of normal blood and result in the equation: (1) B/G = 0.8 W/G + 0.005 F / G The application of this formula, however, ; Ilose-regulated Penthraneq Anesthesia, Abbott Lab-
oratories. North Chirago, Illinois.
"Assistant Professor, Department of Anesthesiology, IJniversity of M i a m i School of Medicine. a n d Veterans Administration Hospital, Miami, Florida 33152. T h i s study was supported in p a r t by N I H G r a n t #GM l(i198 a n d funds from t h e Miami Veterans Administration Hospital. Paper received: 9/2/75 Accepted for publication: 1/22/76
,
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