[Airway difficulty associated with multiple teratisms of the oral cavity in a newborn infant]

A 13-day-old infant with multiple teratisms of the oral cavity was scheduled for resection of the epignathus. Her oral cavity was occupied by large epignathus, submandibular tumor, congenital bifid tongue and cleft palate, but she had no other congenital abnormalities. We anticipated that an endotracheal intubation would be difficult because of the large size of the tumor in relation to the oral cavity. Initially, awake intubation using a standard laryngoscope was attempted. Although a large elastic epignathus did not interrupt the insertion of the curved laryngoscope blade, the hard submandibular tumors protruded from the submaxillary ramport interfered with mid-line management of the laryngoscope. After several attempts of intubation, a better exposure was obtained and she was successfully intubated using a stylet under deep sedation. We recognized that a careful observation of anatomical abnormalities in the oral cavity is important to keep airway in an infant with multiple abnormalities of the oral cavity.

[Severity and prognosis of congenital diaphragmatic hernia from the viewpoint of perioperative respiratory function]

We studied severity and prognosis of congenital diaphragmatic hernia (CDH) by using preductal arterial blood gas analysis (BGA) and pulmonary function tests (PFTs) in 29 newborn infants. CDH was diagnosed within 24 hours of life, and surgical repair was performed through an abdominal approach after a period of stabilization. The infants were classified into the following three groups based on the highest preoperative alveolar-arterial oxygen tension difference (A - aDO2) and the lowest arterial carbon dioxide pressure (PaCO2) values; Group A (n = 15) : A - aDO2 < 500 mmHg, PaCO2 < 40 mmHg, Group B (n = 7) : A - aDO2 > or = 500 mmHg, PaCO2 < 40 mmHg, Group C (n = 7) : A - aDO2 > or = 500 mmHg, PaCO2 > or = 40 mmHg. Furthermore, the patients were classified into the following three groups based on the preoperative respiratory system compliance (Crs) and forced vital capacity (FVC) values; Group D (n = 8) : Crs < 0.5 ml.cmH2O-1.kg-1, FVC < 10 ml.kg-1, Group E (n = 4) : Crs < 0.5 ml.cmH2O-1.kg-1, FVC > or = 10 ml.kg-1, Group F (n = 17) : Crs > or = 0.5 ml.cmH2O-1.kg-1, FVC > or = 10 ml.kg-1. The mortality in the Group C was significantly higher than in the Group A and B, and the preoperative Crs and FVC values in the Group C were significantly lower than the other groups. The mortality in the Group D and E were significantly higher than the Group F. In conclusion, it is suggested that the preoperative Crs value less than 0.5 ml.cmH2O-1.kg-1 indicates severe pulmonary hypoplasia and is critical for survival.

[Evaluation of postoperative hypoxemia after spinal anesthesia with a pulse oximeter]

We investigated postoperative hypoxemia after spinal anesthesia in 24 adult patients by monitoring SPO2 with a pulse oximeter for 5 hours in the ward. The patients received spinal anesthesia with 0.5% hyperbaric tetracaine and sedated with midazolam during operation. Twelve patients inhaled 3 l.min-1 oxygen via a mask for initial 3 hours, and the other breathed room air all the time. In two of the patients breathing room air, SPO2 decreased to less than 94%. In patients inhaling oxygen, SPO2 was maintained above 98% but decreased significantly after stopping oxygen inhalation (below 94% in five patients). The postoperative SPO2 value correlated significantly with BMI (body mass index) and preanesthetic SPO2, but not with the dose of midazolam or supplemental pentazocine, and postoperative conscious states. In conclusion, there are some incidences of postoperative hypoxemia after spinal anesthesia irrespectively of the dose of midazolam used intraoperatively. Inhalation of 3 l.min-1 oxygen via a mask is sufficient to prevent such postoperative hypoxemia.

[The effect of low-dose prostaglandin E1 on serum and urinary fluoride concentrations in patients anesthetized with sevoflurane]

We investigated the effects of low-dose prostaglandin E1 (PGE1) on serum and urinary concentrations of inorganic fluoride in 39 adult patients undergoing upper abdominal surgery. Anesthesia was maintained with a combination of N2O-O2-sevoflurane and thoracic epidural anesthesia. Twenty-two patients received infusion of PGE1 at a rate of 0.02 micrograms.kg-1.min-1 throughout surgery. Seventeen patients served as control by not receiving PGE1. Serum inorganic fluoride concentrations (FB) were determined before the induction of anesthesia and 0, 2 and 24 hours after the end of anesthesia. Urinary inorganic fluoride concentrations (FU) were determined before the induction of anesthesia, and 0, 24 and 48 hours after the end of anesthesia. These was no difference between PGE1 group and control group in anesthetic dose (MAC hours) of sevoflurane. In both groups, FB peaked at the end of anesthesia. In PGE1 group, UB peaked at the end of anesthesia, while in control group, it peaked 24 hours after anesthesia. There were differences between groups neither in FB nor in FU throughout the study period. The relationships between anesthetic dose and fluoride concentrations, however, differed significantly between the groups. In control group FB values of 0, 2 and 24 hours after anesthesia correlated positively with MAC hours, respectively, while in PGE1 group they did not. Similarly in control group, FU values of 24 and 48 hours after anesthesia correlated positively with MAC hours, respectively, while in PGE1 group, they did not. Thus in patients receiving high-dose sevoflurane, FB and FU tended to be lower in PGE1 group than in control group. In contrast, in PGE1 group, urinary excretion of fluoride during surgery correlated positively with MAC hours, while in control group, it did not. Urinary fluoride excretion during surgery was significantly greater in PGE1 group than in control group. These results suggested that PGE1 might prevent elevation of serum and urinary fluoride concentrations in patients receiving high-dose sevoflurane. This effect might result from enhanced urinary excretion of fluoride with PGE1.

Plasma somatostatin correlates with blunted thyrotropin secretion after stimulation by thyrotropin-releasing hormone in critical illness

To clarify whether plasma somatostatin affects thyrotropin secretion in critical illness, plasma somatostatin and thyrotropin responses to thyrotropin-releasing hormone were studied in forty-three critically ill patients. High somatostatin levels were associated with blunted thyrotropin secretion in critically ill patients. There was an inverse correlation between plasma somatostatin levels and the maximum increment of thyrotropin after stimulation by thyrotropin-releasing hormone. Decreased somatostatin and increased thyrotropin secretion before discharge from the intensive care unit were demonstrated in survivors. On the other hand, non-survivors maintained high somatostatin levels and had blunted thyrotropin secretion during their intensive care admission. These results suggest that high plasma somatostatin levels may play a role in the blunted thyrotropin secretion observed in critical illness.

[The effect of low-dose prostaglandin E1 on intra- and post-operative liver function]

We investigated the effects of low-dose prostaglandin E1 (PGE1) on intra- and post-operative liver function in 109 adult patients undergoing upper abdominal surgery. Patients were divided into 2 groups; Control group (n = 42) and PGE1 group (n = 67). In PGE1 group, PGE1 was infused throughout surgery at a rate of 0.02 microgram kg-1 min-1. In both groups, anesthesia was maintained with a combination of inhalational and thoracic epidural anesthesia. Epidural anesthesia was maintained with 1.5% lidocaine infused epidurally at a constant rate (8 +/- 2 ml.hr-1). The continuous epidural infusion of lidocaine was initiated before surgery and discontinued at the end of surgery. Preoperative and postoperative liver function was evaluated with blood chemistry examination. Intraoperative liver function was evaluated in 84 patients (33 in control group and 51 in PGE1 group) by measuring plasma lidocaine concentration. Plasma lidocaine concentration was determined 1 and 3 hours after the initiation of lidocaine infusion and 0 and 2 hours after its termination. There were no differences between the groups in doses and infusion rates of lidocaine. In both groups, lidocaine concentration increased progressively as infusion was continued. Lidocaine concentration was significantly lower in PGE1 group than in control group at the end of the infusion. In 22 patients in control group and 35 in PGE1 group who received high-dose lidocaine (> 8 mg.kg-1), lidocaine concentration remained significantly lower in PGE1 group than in control group throughout the infusion period. The difference in lidocaine concentrations between the groups increased progressively as infusion was continued, though the doses and the infusion rates of lidocaine were not different between the groups. Postoperative liver function did not differ between the groups. Because removal of lidocaine from blood to liver parallels hepatic blood flow, the lower plasma lidocaine concentration in PGE1 group indicated that hepatic blood flow was higher and liver function was better-maintained with PGE1 during anesthesia and surgery. Low dose PGE1 thus improved intraoperative liver function during upper abdominal surgery.

[A review of pregnancy-induced analgesia]

Pregnancy-induced analgesia is of interest to anesthesiologists because of a general clinical impression that a parturient has a lowered requirement for anesthetics and analgesics. This fact may be mainly explained that endogenous analgesic mechanisms are stimulated by pregnancy. It has been suggested that stress activates natural pain-inhibitory systems mediated by endogenous opioid and non-opioid mechanism. Activation of intrinsic analgesia systems by stress is described based on a review of literature. This paper will give an overview of experimental and clinical studies regarding pregnancy-induced analgesia and will discuss mechanisms and potential implications for novel therapeutic approaches.

Inhibition of voltage-dependent Ca2+ channels of porcine tracheal smooth muscle by the novel Ca2+ channel antagonist RWJ-22108

1. We compared electrophysiological effects of the bronchoselective Ca2+ channel antagonist RWJ-22108 on voltage-dependent Ca2+ channels (VDCs) of porcine tracheal smooth muscle cells to the effects of nicardipine and verapamil. 2. Each of the three Ca2+ channel antagonists tested inhibited inward Ca2+ currents (ICa) measured by whole-cell patch clamp techniques. Inhibition was dose-dependent with approximately 50% inhibition of peak ICa at +20 mV obtained with 3 x 10(-6) M RWJ-22108, 3 x 10(-7) M nicardipine, or 10(-5) M verapamil. 3. Both RWJ-22108 (3 x 10(-6) M) and nicardipine (3 x 10(-7) M) shifted the voltage dependence of steady-state inactivation to more negative potentials; however, the change in the potential of half-maximal inactivation induced by RWJ-22108 (-18 mV) was significantly greater than that induced by nicardipine (-12 mV). Verapamil did not alter the voltage dependence of inactivation. 4. We conclude that inhibition of VDCs by RWJ-22108 is qualitatively similar to that by nicardipine but with a greater stabilizing effect on the inactivated channel state.

[Preoperative flurbiprofen provides pain relief after laparoscopic cholecystectomy]

In a single-blind randomized prospective study, postoperative pain was assessed in 60 patients undergoing elective laparoscopic cholecystectomy with three types of anesthesia: standardized general anesthesia (control group), preoperative 50 mg flurbiprofen as an addition to the same method of general anesthesia (flurbiprofen group), and conventional combined epidural and general anesthesia with epidural administration of 0.25% bupivacaine 5-8 ml and 0.1-0.2 mg buprenorphine after surgery (epidural group). After the operation we found that the average time from the end of surgery to the first request for an analgesic was 3.9 h, 22.7 h and 43.7 h in the control, flurbiprofen and epidural group, respectively. Substantially it was longer in the flurbiprofen and epidural group than in the control group (P < 0.01 and < 0.001, respectively). Patients in the control group requested analgesics for a longer period of time after the initial request compared with patients in the other groups. Our results indicate that postoperative pain can be reduced when flurbiprofen is added to general anesthesia before surgery, although use of flurbiprofen was not as effective as the conventional combined epidural and general anesthesia used for treating pain after laparoscopic cholecystectomy.

[The effect of low-dose prostaglandin E1 on intra- and post-operative renal function]

We investigated the effects of low-dose prostaglandin E1 (PGE1) on intra- and post-operative renal function in 109 adult patients undergoing upper abdominal surgery. Anesthesia was maintained with a combination of thoracic epidural combined with inhalational anesthesia. Sixty-seven patients received PGE1 at a rate of 0.2 microgram.kg-1.min-1 throughout surgery. Forty-two patients, who did not receive PGE1, served as control. Pre- and post-operative renal function was evaluated with serum levels of BUN and creatinine (Cr), while intra-operative renal function was evaluated mainly with urine output and urine flow rate during anesthesia. Urinary Na excretion and creatinine clearance (Ccr) were determined during surgery in limited cases. Urine output and urine flow rate during anesthesia were greater in PGE1 group than in control group, whereas infusion volumes and infusion rates were not different between the groups. In PGE1 group, urine flow rate was greater during surgery than before surgery, while in control group, it was unchanged. Na excretion during anesthesia was also greater in PGE1 group than in control group. In control group, Na excretion and Ccr were smaller during surgery than before surgery, while in PGE1 group, they were unchanged. Postoperative serum BUN and creatinine levels were not different between the groups. Decreased Na excretion and decreased Ccr in control group indicated that renal function was depressed during surgery, whereas unchanged Ccr, unchanged Na excretion and increased urine flow rate in PGE1 group indicated that renal function was well-maintained during surgery with PGE1. Low-dose PGE1 thus prevented depression of renal function during surgical anesthesia.

Blockade of ATP-sensitive K+ channel abolishes the anti-ischemic effects of isoflurane in dog hearts

BACKGROUND

Although isoflurane is reported to have a protective effect against ischemic damage on the myocardium, the mechanisms of this effect are not clear. Activation of adenosine triphosphate sensitive potassium (KATP) channels is indicated to protect myocardium during ischemia. Thus, it was hypothesized that if isoflurane could activate KATP channels, blockade of KATP channels would decrease its cardioprotective effect.

METHODS

Mongrel dogs, anesthetized with morphine, urethane, and chloralose, were subjected to 15 min of left anterior descending coronary artery occlusion followed by 60 min reperfusion. The dogs were divided into three groups: the control group (n = 8), ISO group (n = 8) and ISOGC group (n = 8). In the ISO and ISOGC groups, 1 MAC of isoflurane was administrated during ischemia and reperfusion. In the ISOGC group, 0.3 mg/kg of glibenclamide, the KATP channel blocker, was given 45 min before ischemia. Full-thickness samples of myocardium were obtained and the concentrations of adenosine monophosphate, adenosine diphosphate, adenosine triphosphate (ATP), creatine phosphate and lactate in the endocardial portion of the myocardium were measured.

RESULTS

The ischemia-reperfusion caused a 25.4% and 27.6% reduction of myocardial ATP in the control and ISOGC groups, respectively. In contrast, the ISO group showed only 11.0% reduction of ATP, which was significantly lower compared to the other groups (P < 0.01).

CONCLUSIONS

Our results shows that blockade of the KATP channel abolishes cardioprotective effects of isoflurane in myocardial ischemia-reperfusion. The KATP channel may play a role in the ATP-sparing effect of isoflurane.

[Clinical evaluation of low flow anesthesia machine ACOMA ACM-10]

We studied low flow anesthesia using ACOMA ACM-10 anesthesia machine in 39 patients undergoing elective surgery. Randomly, 29 patients were allocated to low flow anesthesia group and 10 patients were allocated to high flow anesthesia group. After the induction, anesthesia was maintained with 2 l.min-1 of oxygen, 4 l.min-1 of nitrous oxide and sevoflurane (high flow anesthesia). After 15 minutes of high flow anesthesia, the total gas flow was reduced to 300 ml.min-1 of oxygen, 300 ml.min-1 of nitrous oxide or reduced to 400 ml.min-1 of oxygen, 200 ml.min-1 of nitrous oxide in the low flow anesthesia group. In the high flow anesthesia group, the high flow was maintained. The inspiratory oxygen concentration was maintained during anesthesia more than 35% in the low flow group and 33% in the high flow group. The absolute humidity in the inspiratory gas and the soda lime temperature were significantly higher during low flow anesthesia. The sevoflurane consumption in the low flow anesthesia group was reduced to less than 1-8th that of high flow anesthesia group. In conclusion, we could perform low flow anesthesia safely and economically with the ACM-10 anesthesia machine.

[The effect of low-rose prostaglandin E1 on circulation, respiration and body temperature during surgical anesthesia]

We investigated the effects of low-dose prostaglandin E1 (PGE1) on circulation, respiration, and body temperature during surgical anesthesia. We studied 109 adult patients undergoing upper abdominal operations under thoracic epidural combined with inhalational anesthesia. Patients were divided into 2 groups; Control group (n = 42) and PGE1 group (n = 67). In PGE1 group, PGE1 infusion was started at the rate of 0.02 microgram.kg-1.min-1 before the induction of anesthesia and was terminated at the end of surgery. There were no differences between the groups in demographic, anesthetic and surgical characteristics. After treatment with PGE1, arterial pressure decreased slightly but significantly, resulting in lower arterial pressure in PGE1 group than in control group before the induction of anesthesia. After the induction of anesthesia, however, arterial pressure decreased significantly in both groups, and the differences in arterial pressure between the groups were not observed any more during surgery. Heart rate was not different between the groups throughout the study period. Intraoperative urine output was greater in PGE1 group than in control group. PaO2/FIO2 ratio was not different between the groups both before and during anesthesia. Rectal temperature remained slightly but significantly lower in PGE1 group throughout surgery. Rectal-to-palm temperature gradient tended to be smaller in PGE1 group 1 hour after the induction of anesthesia. Low-dose PGE1 reduced arterial pressure. However, the difference in arterial pressure between the groups was so small that the difference disappeared during surgery. Meanwhile, low-dose PGE1 increased urine output, suggesting that renal blood flow was better-maintained with PGE1. In spite of several investigations reporting an unfavorable effect of PGE1 on PaO2, low dose PGE1 did not affect PaO2 in this study. Finally low-dose PGE1 reduced core temperature, though slightly, probably through redistribution of the body heat.

Stimulation of angiotensin subtype 2 receptor reduces basal cGMP levels in the neointima of rat aorta after balloon injury

1. The association between the stimulation of the angiotensin subtype 2 receptor (AT2-R) and the change in tissue levels of cyclic nucleotide was assessed on neointima formation in rat aorta following aortic balloon injury. 2. Tissue levels of guanosine 3',5'-cyclic monophosphate (cGMP) and adenosine 3',5'-cyclic monophosphate levels (cAMP) in the injured and uninjured aorta was determined by enzyme immunoassay at baseline and again 30 s after administration of 10(-7) M angiotension II. 3. Injured and uninjured aorta showed no difference in basal levels of cGMP. Angiotension II reduced the basal level of cGMP in the injured aorta only. 4. This decrease was blocked by a selective AT2-R antagonist (PD123319) and by a nonselective angiotensin II antagonist (angiotensin II antipeptide), but not by a selective angiotensin subtype 1 antagonist (CV-11974). 5. Stimulation with a selective AT2-R caused no change in the level of cAMP in the injured or uninjured aorta. 6. Results suggest that stimulation of AT2-R in proliferative neointima leads to a decreased tissue level of cGMP.

Obstructive ileus caused by a swallowed foreign body (a "press-through" package) and preexisting adhesions

A "press-through" package (PTP), because it is large and square-shaped, tends to be caught in the esophagus when swallowed. A rare case of obstructive ileus induced by a PTP that was swallowed by 54-year-old man with a history of diabetes mellitus and acute appendectomy is reported. The PTP was 19 mm x 18 mm and was lodged in the cecum, which was stenosed because of preexisting intestinal adhesions; consequently, the PTP obstructed the ileus. The PTP was surgically removed.

Effects of thoracic epidural anesthesia on changes in ischemic myocardial metabolism induced by intracoronary injection of endothelin in dogs

OBJECTIVE

Thoracic epidural anesthesia (TEA) has been reported to alleviate ischemic damage to the myocardium. Endothelin, an endothelium-derived peptide and a potent coronary vasoconstrictor, may contribute to poor cardiac perfusion and ischemia. The objective was to examine regional myocardial metabolism during ischemia caused by intracoronary injection of endothelin with and without TEA.

DESIGN

The three experimental groups and three treatments were randomized.

SETTING

All studies were conducted in a university research laboratory.

PARTICIPANTS

Thirty anesthetized dogs comprised the study groups.

INTERVENTIONS

Study animals were divided into three groups of 10 animals each identified as normal saline (NS); TEA; and TEA + blood pressure controlled (TEA + BPC). The NS group had 0.5 mL/kg of normal saline injected into the T4-5 epidural space. The TEA group had 0.5 mL/kg of saline containing 1% lidocaine injected into the T4-5 space. The TEA + BPC group had blood pressure and heart rate maintained at pre-epidural injection values by partially occluding the descending aorta and by atrial pacing. Endothelin (15 pmol/kg) was bolus injected into the left anterior descending (LAD) artery of each heart. Systolic and diastolic blood pressure, heart rate, and LAD coronary blood flow (CBF) were monitored. Three minutes after injection of endothelin, myocardial tissue was sampled from the distribution of the LAD artery and from the control, left circumflex (LCx) artery. ATP, ADP, AMP, lactate, and pyruvate were measured by enzymatic methods.

MEASUREMENTS AND MAIN RESULTS

It was found that in each group endothelin consistently decreased LAD CBF, but the decrease was less in the TEA + BPC group. In the tissue distribution of the LAD, the levels of ATP and energy charge potential were lower, and the level of lactate was higher in the NS group than in the TEA or the TEA + BPC groups (p < 0.01).

CONCLUSIONS

These results confirm that (1) endothelin injected into the LAD artery decreases CBF and causes selective myocardial ischemia in a fashion similar to intravascular stenosis of the LAD rather than to mechanical occlusion and (2) TEA, with or without pressure support, lessens the degree of regional ischemia induced by injection of endothelin in the LAD.

[Anesthesia combined with profound hypothermia using cardiopulmonary bypass for clipping of giant basilar artery aneurysm]

A 52 year-old female was scheduled for clipping of giant basilar artery aneurysm. This operation needed temporary clipping of the basilar artery for 30-40 minutes, and preoperative examination suggested that some regions would become ischemic by temporary clipping. Therefore profound hypothermia using cardiopulmonary bypass (CPB) and thiamylal loading were planned to prevent cerebral damage during the operation. Anesthesia was induced with thiamylal, fentanyl, and isoflurane in nitrous oxide and oxygen. Following administration of vecuronium, trachea was intubated. Two hours after the start of surgery, thiamylal was titrated to obtain EEG patterns of burst-suppression before CPB and the infusion was continued until CPB was discontinued. With burst-suppression present, CPB was instituted. Hypothermia below 20 degrees C at pulmonary artery temperature was maintained until the aneurysm was clipped and bleeding from the operating site was controlled. Cooling and rewarming by CPB were carried out with ease and uneventfully. The patient had no neurological complications postoperatively.

[Potentiation of procaine-induced local sensory block by verapamil in rats]

We have studied the effects of calcium-channel blocker, verapamil, on procaine-induced local sensory block. Standardized tail-flick (TF) test was used to investigate the duration and intensity of procaine-induced local conduction block in rats. After obtaining baseline TF latencies (mean; 3.3 sec), two 100 microliters of 0.4% procaine alone, a combination of 0.4% procaine and verapamil (100 micrograms, or 200 micrograms), or a large dose of verapamil (200 micrograms) were injected to the opposite sites of the tail base and TF test was performed every five minutes for 45 minutes. A large dose of verapamil showed no prolongation of TF latencies. The administration of 0.4% procaine alone produced a significant increase of TF latencies and the peak effect of % MPE (percent maximum possible effect) was demonstrated at 4 minutes after the drug injection (mean % MPE; 37.0%). Coadministration of 0.4% procaine and two doses of verapamil produced significant increases of % MPE in a dose-dependent fashion. It was concluded that sensory block by procaine of the peripheral nerves is potentiated by coadministration of calcium-channel blocker, verapamil.

Pharmacological premedication for anaesthesia

The psychological component of preoperative preparation should be completed with a selective use of drugs. The days of poly-pharmacy are over. Heavily sedated patients coming to the operation room with minimal oral secretions are not the purpose of modern premedication. Anxiolysis and slight sedation (painless patients) and analgesia (patients suffering from pain) are the main goals. Anticholinergics should be used only when needed, as is the case with premedication generally. The use of antiemetics and that of agents given for prophylaxis against allergic reactions or aspiration pneumonitis depend on specific needs of the patient. More accurate and generally accepted but simple methods are needed in studying the effects of different premedicants. The present results produced with a huge number of different more or less validated assessments can seldom be compared with each other.

Comparison of the Jackson-Rees circuit, the pediatric circle, and the MERA F breathing system for pediatric anesthesia

The purpose of this study was to compare the Jackson-Rees circuit with the pediatric circle and MERA F breathing system (MERA F system) for pediatric anesthesia from the viewpoint of work of breathing (WOB). Twenty-three children (2-10 yr old) were studied during spontaneous breathing under endotracheal anesthesia with 4 L/min nitrous oxide, 2 L/min oxygen, and 1% end-tidal concentration of sevoflurane. WOB, inspiratory and expiratory airway resistance, dynamic compliance (CDYN), pressure time product (PTP), and arterial blood gasses were measured in the three circuits. The inspiratory WOB was estimated directly by measuring the esophageal pressure-volume loop using the Campbell technique. In a laboratory study, we measured the compliances of the Jackson-Rees circuit, the pediatric circle, the MERA F system, and the adult circuit. WOB differed among the three circuits (MERA F system > pediatric circle > Jackson-Rees circuit). Inspiratory and expiratory resistances, and arterial carbon dioxide tension in the Jackson-Rees circuit were significantly lower than those of both the pediatric circle and MERA F system. The CDYN and PTP in the MERA F system were significantly higher than those in both the Jackson-Rees circuit and the pediatric circle. The MERA F system had significantly higher compliance than the Jackson-Rees circuit and pediatric circle. It is concluded that the Jackson-Rees circuit is most efficient, the pediatric circle is intermediate, and the MERA F system is the least efficient from the viewpoint of WOB during spontaneous breathing for pediatric anesthesia.

Cardiac arrest during removal of a pulmonary artery catheter

PURPOSE

This case report describes an asystolic cardiac arrest that occurred during removal of a pulmonary artery (PA) catheter.

CLINICAL FEATURES

A 70-yr-old man underwent elective hepatectomy because of hepatic carcinoma with a combination of thoracic epidural blockade and general anaesthesia. After the conclusion of the operation, the PA catheter was removed and immediately after, the patient developed profound sinus bradycardia and hypotension followed by asystolic cardiac arrest. Two minutes after the onset of asystole, cardiac rhythm was detected following the administration of epinephrine and atropine. He had no further episodes of bradycardia or neurological deficit.

CONCLUSION

Removal of a PA catheter has the potential of inducing asystole requiring cardiac resuscitation and availability of emergency drugs.