Difference between arterial and end-tidal carbon dioxide pressures during laparoscopy in paediatric patients

Correlation of arterial PaCO2 to end tidal CO2 in children undergoing laparoscopic abdominal surgery: An observational study

Background and Aims

The reliability of end tidal carbon dioxide (ETCO2) as a measure of arterial carbon dioxide (PaCO2) in pediatric laparoscopy is unclear. We evaluated the correlation of arterial to end tidal P(a-ET) CO2 during pediatric laparoscopy at two hours of pneumoperitoneum as the primary objective. We also compared P(a-ET) CO2 and alveolar to arterial oxygen gradient P(A-a) O2 and haemodynamics at fixed time points during surgery.

Material and Methods

A cross-sectional study was conducted in 25 children undergoing laparoscopic abdominal surgery. Arterial blood gases were drawn at T0, baseline, T10: ten minutes, T1h: 1 hour, T2h: 2 hours of pnuemoperitoneum and T 10d: 10 mins after deflation. The P(a-ET) CO2, P(A-a) O2, were measured from the blood gas and ETCO2 and FiO2 values on the monitor. The Pearson's correlation coefficient, the Wilcoxon rank test and Chi square test were used for statistical analysis.

Results

At T2h moderate correlation of P(a-ET) CO2 (r = 0.605, P = 0.001) with 40% children documenting accurate P(a-ET) CO2, -1 to +1 mm Hg was seen. Moderate correlation was also seen at T0, T10, T 10d but poor correlation at T 1h. The P(A-a) O2 increased progressively with surgery and did not correlate with P(a-ET) CO2. Heart rate was stable, but systolic blood pressures at T 10 and diastolic at T10, T 1h, T 2h were higher than baseline.

Conclusion

Moderate correlation was seen between PaCO2 and ETCO2 at 2 h of pnuemoperitoneum and at T0, T 10, and T 10d. P(A-a) O2 increased with surgery but did not correlate with P(a-ET) CO2.

Hemodynamic, Airway Pressure, and Capnometric Changes and Perioperative Outcome in Pediatric Laparoscopic Inguinal Herniorrhaphy: A Comparison with Open Inguinal Herniorrhaphy

Background:

Laparoscopic procedures which are now established in pediatric population as well exposes the child to supplemental cardiorespiratory changes due to increase in intraabdominal pressure (IAP) and hypercarbia.

Aims:

This study aims to analyze the effects of pneumoperitoneum and postural modifications on cardiorespiratory system (primary outcome) during pediatric laparoscopic herniorrhaphy (LH) and its comparison with open herniorrhaphy (OH) and assessment of overall perioperative outcome (secondary outcome).

Settings and Design:

A prospective, observational study conducted in a tertiary care hospital.

Materials and Methods:

Fifty children undergoing either LH (n = 25) or OH (n = 25) were included in the study. Anesthetic procedure was standardized. Parameters monitored were heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressures (MAP), electrocardiogram lead-II, end-tidal CO₂ (ETCO₂), airway pressures P_Peak, P_Plateau, P_Mean, pulse oximetry, IAP, minute ventilation/respiratory rate alterations.

Statistical Analysis Used:

Student's t-test and Chi-square test were applied to compare different variables between the two groups. Intragroup analysis was done using the analysis of variance test.

Results:

The HR was comparable in both groups. The rise in SBP, DBP, and MAP was 9% (102.88 ± 6.91–121.32 ± 6.63), 19% (60.88 ± 4.94–77.00 ± 9.75), and 14.8% (73.92 ± 4.65–90.40 ± 8.42), respectively, in group LH. The rise in peak, plateau, and mean airway pressures was 19.4% (14.20 ± 2.00–18.00 ± 2.54), 20.1% (13.32 ± 1.89–16.89 ± 2.60), and 16.1% (6.20 ± 1.00–7.47 ± 0.96), respectively, in group LH. ETCO₂ showed a maximum rise of 19.4% (34.52 ± 3.61–41.21 ± 3.99) in group LH. In laparoscopic group, recurrence was seen in 3 patients.

Conclusions:

We found significant hemodynamic, airway pressure, and capnometric changes during pediatric LH with comparable perioperative outcome among the two groups.

Perioperative Anaesthetic Approach in a Homozygous Sickle Cell Anaemia Patient with Frequent Pain Crises

Sickle cell disease (HbS) is a haemolytic anaemia characterized by the formation of abnormal haemoglobin. In patients with sickle cell disease, high rates of erythrocyte generation, degradation, and hyperbilirubinemia increase the risk for cholelithiasis. Previous studies have found that the incidence of cholelithiasis is 70% in adult patients. In sickle cell disease, decreased oxygen concentration leads to the sickling of erythrocytes by causing aggregation and polymerization. Sickle erythrocytes can have devastating effects on many vital organs by causing microvascular occlusion. In patients with sickle cell anaemia, anaesthetic technique, anaesthetic agents, and surgical trauma may cause additional risk. In this case report, we present a perioperative anaesthetic approach in the laparoscopic cholecystectomy of a patient with HbS, elevated liver function tests, and frequent pain crises.

Physiological impact of pneumoperitoneum on gastric mucosal CO2 pressure during laparoscopic versus open appendectomy in children

INTRODUCTION

Funded knowledge about the physiological impact of laparoscopic surgery in children is sparse. Although there are data on hemodynamic compromise after creation of a pneumoperitoneum in children, little is known about microcirculatory changes at the mucosa level. Therefore, the aim of this study was to assess gastric microcirculation by continuous gastric air tonometry in the setting of laparoscopic versus open appendectomy.

PATIENTS AND METHODS

Twenty children 5-17 years old undergoing laparoscopic and 7 children undergoing open appendectomy were included in the study. Gastric intramucosal CO(2) pressure (pCO(2)i) was measured under standardized flow and intraperitoneal pressure using continuous air tonometry (TONOCAP(®), Datex Ohmeda), and ΔpCO(2) (pCO(2)i - end-expiratory CO(2) pressure [pCO(2)e]) was obtained for the time course of surgery.

RESULTS

ΔpCO(2) increased significantly from the baseline value not only in the laparoscopic group but also in the open surgery group. Even though ΔpCO(2) was higher in the laparoscopic group at all time points, the overall increase in ΔpCO(2) for both groups was uniform. The largest differences were observed during the initial 20 minutes of the operation. The changes observed were exclusively due to an increase of pCO(2)i in relation to a constant pCO(2)e.

DISCUSSION

In the setting of a standardized, simple operation in an otherwise healthy child above the age of 5 years, our data suggest that the effect of a pneumoperitoneum on splanchnic perfusion is comparable to the compromise caused by open surgery. Further research must be obtained when evaluating the full impact of laparoscopy in children.

Transcutaneous carbon dioxide monitoring accurately predicts arterial carbon dioxide partial pressure in patients undergoing prolonged laparoscopic surgery

BACKGROUND

There may be large differences between measurements of end-tidal carbon dioxide partial pressure (Petco(2)) and arterial carbon dioxide partial pressure (Paco(2)) during laparoscopic surgeries. Transcutaneous carbon dioxide (Ptcco(2)) monitoring can be used to noninvasively and continuously estimate Paco(2). In the present study we evaluated the accuracy of Ptcco(2) monitoring in predicting the Paco(2) during laparoscopic surgeries with prolonged pneumoperitoneum.

METHODS

Sixteen patients who underwent laparoscopic radical gastrectomy or radical proctectomy under general anesthesia were included in the study. Their Paco(2), Petco(2), and Ptcco(2) values were measured at 3 time points before and after pneumoperitoneum. Agreement among measures was assessed by the Bland-Altman method.

RESULTS

Forty-eight sample sets were obtained. The average Paco(2)- Ptcco(2) difference was -0.9 + or - 6.4 mm Hg (mean + or - 2 SD). The average Paco(2) - Petco(2) difference was 7.5 + or - 7.0 mm Hg (mean + or - 2 SD). Paco(2) - Ptcco(2) was less than or equal to + or -5 mm Hg for 88% of the samples. Paco(2) - Petco(2) was less than or equal to + or -5 mm Hg for 17% of the samples (P < 0.05).

CONCLUSIONS

While undergoing long-term pneumoperitoneum laparoscopic surgery, Ptcco(2) monitoring is more accurate than is PETCO(2) monitoring in predicting the patients' Paco(2).

Arterial to endtidal carbon dioxide gradient during pediatric laparoscopic fundoplication

BACKGROUND

Discrepancies between arterial carbon dioxide (P(a)CO(2)) and endtidal carbon dioxide (ETCO(2)) measures have been demonstrated in ventilated children with cyanotic congenital heart disease, infants with respiratory failure and during visceral and urological laparoscopic surgery.

OBJECTIVES

Our objective was to assess the extent of the P(a)CO(2) to ETCO(2) gradient in children during laparoscopic fundoplication.

METHODS

We prospectively collected data on patient characteristics, surgical conditions, pH, ETCO(2)and P(a)CO(2) during laparoscopic fundoplication using carbon dioxide insufflation in children age <29 months.

RESULTS

Data were collected on nine cases, four cases aged <1 year. A P(a)-ETCO(2) gradient was present during insufflation. The gradient was larger in children age less than 1 year but statistically significantly different from a value of zero, only at t = 30 min (mean = 8 mmHg, sem = 0.81, P = 0.004) and t = 60 min (mean = 5 mmHg, sem = 1, P = 0.014). Minute ventilation was increased from 20% to 100% to control ETCO(2).

CONCLUSIONS

ETCO(2) may not accurately represent arterial values during laparoscopic fundoplication, especially in the infant when carbon dioxide insufflation is used. Consideration should be given to placing an arterial line for blood gas measurement in some patients.

Physiological responses to endoscopic surgery in children

The knowledge on the physiological impact of endoscopic surgery in infants and children is limited. Cardiovascular effects of pneumoperitoneum are mainly the result of an increase in intraabdominal pressure, absorption of carbon dioxide, and a stimulation of the neurohumoral vasoactive system. In infants, pneumoperitoneum alters the heart rate, mean arterial pressure, left ventricular endsystolic and end-diastolic volume, and meridional wall stress. Urine production is significantly reduced, and cerebral oxygenation and blood flow are altered. However, postoperative immune function is preserved or restored faster, and specific physiological responses to endoscopic surgery are well tolerated by otherwise healthy infants and children. The effects in children with specific conditions, such as sepsis, cancer, or organ dysfunction, remain to be investigated.

Absorption of carbon dioxide during laparoscopy in children measured using a novel mass spectrometric technique

BACKGROUND

Carbon dioxide (CO(2)) is absorbed during pneumoperitoneum and may cause adverse haemodynamic effects. The aim of this study was to measure the elimination of exogenous CO(2) during laparoscopy in children.

METHODS

Ten children [27.6 (56.5) months; mean (SD)] undergoing laparoscopic and nine [24.5 (17.3) months] undergoing open surgery were studied. Breath samples were collected at the line for end-tidal CO(2) and analysed for (13)CO(2)/(12)CO(2) ratio expressed as deltaPDB (difference from standard), by isotope-ratio mass spectrometry. The proportion of absorbed CO(2) was calculated comparing exhaled (13)CO(2)/(12)CO(2) before and during CO(2) pneumoperitoneum.

RESULTS

(13)CO(2)/(12)CO(2) in medical CO(2) was -32.7 (2.1) deltaPDB. (13)CO(2)/(12)CO(2) in breath of patients undergoing open procedures was -24.3 (2.4) deltaPDB at the start of operation and did not change during the operation (P > 0.2). (13)CO(2)/(12)CO(2) in breath of patients undergoing laparoscopy was -21.5 (5.4) deltaPDB at the start of insufflation, and decreased during pneumoperitoneum by 2.5 (1.6) deltaPDB, indicating absorption of exogenous CO(2). The percentage of expired CO(2) absorbed rose to 15.5 (7.7)% after 30 min of pneumoperitoneum and decreased rapidly after desufflation.

CONCLUSION

After 10 min of laparoscopy 10-20% of expired CO(2) derives from the exogenous CO(2). CO(2) absorption can be measured using a simple mass spectrometric technique.

The influence of physiotherapy and suction on respiratory deadspace in ventilated children

OBJECTIVE

To assess and compare the effects of respiratory physiotherapy and suction on deadspace volumes, carbon dioxide elimination (VCO(2)), end tidal CO(2) (ETCO(2)), and arterial partial pressure of carbon dioxide (PaCO(2)) in ventilated infants and children.

DESIGN

Randomised crossover study. Participants received both treatments with a washout interval of more than 90 min.

SETTING

Intensive tertiary care units, Great Ormond Street Hospital, London.

PATIENTS

Eighty-seven fully ventilated children, requiring physiotherapy, with arterial lines in situ. Paired measurements were obtained in 81 patients, of whom 6 were excluded because of tracheal tube leak greater than 20%.

INTERVENTIONS

Respiratory physiotherapy and suction.

MEASUREMENTS AND RESULTS

Data were collected April 1998-March 2000. The "CO(2)SMO Plus" respiratory monitor was used to calculate parameters before and 30 min after both interventions. Physiotherapy lasted longer and required more saline and catheters per treatment ( p<0.005). There were significant increases in physiological deadspace (VD(phys))/kg ( p<0.0001), alveolar deadspace (VD(alv))/kg ( p<0.0001) and VD(phys)/tidal volume (V(T)) ( p<0.05) following physiotherapy that were not observed following suction. There were no significant changes following either treatment with respect to airway deadspace (VD(airway)), VCO(2) or PaCO(2). Comparison of the mean differences following treatments indicated significant differences between physiotherapy and suction in terms of VD(phys)/kg ( p<0.005), VD(alv)/kg ( p<0.005), expired tidal volumes (V(TE)) ( p<0.05), mixed expired CO(2) (PeCO(2)) ( p<0.04) and ETCO(2) ( p<0.03).

CONCLUSIONS

Differences between physiotherapy and suction techniques probably accounted for their statistically distinguishable effects on deadspace. VD(phys) and VD(alv) may be more sensitive indicators of subtle changes in gas exchange and regional ventilation than VCO(2) or PaCO(2). However, interpretation of these outcomes is dependent on concurrent examination of the parameters from which they are derived.

Correlação entre as pressões parciais de co2 no ar expirado e no sangue arterial, em porcas submetidas a pneumoperitônio

OBJETIVO: As cirurgias realizadas por via laparoscópica, que utilizam CO2 para realização do pneumoperitônio, cursam com hipercarbia. Esta alteração pode ser estimada pela pressão parcial de CO2 no ar expirado. Este trabalho foi realizado com a finalidade de determinar se há correlação entre pressão parcial de CO2 arterial e pressão parcial de CO2 no ar expirado nas cirurgias por via laparoscópica. MÉTODO: Distribuíram-se 20 porcas em dois grupos: sem pneumoperitônio e com pneumoperitônio de 12 mmHg de pressão intra-abdominal. Foram medidas a pressão endotraqueal, saturação arterial de O2, pressão parcial de CO2 no ar expirado, pH e pressão parcial de CO2 arteriais. RESULTADOS: Após a realização do pneumoperitônio foi encontrado aumento significativo da pressão endotraqueal, da pressão parcial de CO2 no ar expirado e pressão parcial de CO2 arterial. CONCLUSÕES: Apesar de ter ocorrido aumento nas pressões parciais de CO2 tanto arterial quanto no ar expirado, não houve correlação linear entre elas, não se podendo estimar em cirurgias por via laparoscópica a pressão parcial de CO2 arterial pela pressão parcial de CO2 no ar expirado.

Carbon dioxide elimination during laparoscopy in children is age dependent

The absorption of carbon dioxide (CO2) used for positive pressure pneumoperitoneum may lead to an increased CO2 load. CO2 elimination during laparoscopy has not been investigated previously in paediatrics. The aim of this study was to characterise the pattern of CO2 elimination during laparoscopic surgery in infants and children.

METHODS

Twenty children undergoing laparoscopy and 19 children undergoing laparotomy for elective abdominal operations were studied. Pneumoperitoneum was achieved using insufflation of unheated CO2. CO2 elimination (metabolically produced + absorbed; milliliters per kilogram per minute) was measured minute by minute during the operation by indirect calorimetry. End-tidal CO2 (kPa) was recorded every 10 minutes. The above variables were assessed before CO2 insufflation, during pneumoperitoneum, and after desufflation.

RESULTS

Before insufflation, CO2 elimination was 4.6 +/- 0.3 ml/kg/min and increased after 15 minutes of pneumoperitoneum to 5.2 +/- 0.3 (P <.001). Post desufflation, CO2 elimination decreased toward preinsufflation values, but did not return to baseline by the end of operation (5.8 +/- 0.3; P <.001). End-tidal CO2 was 4.7 +/- 0.2 preinsufflation, peaked at 1 hour (5.3 +/- 0.2; P <.001) and subsequently decreased in response to ventilatory adjustments. The total amount of CO2 insufflated was positively correlated with patient age (r2 = 0.27; P <.01). CO2 elimination was age related, as indicated by multilevel model analysis and by negative correlations between maximum increase in CO2 elimination and both age (r2 = 0.27; P <.01) and weight (r2 = 0.29; P <.01). These data suggest that the younger or smaller the child, the larger the increase in CO2 elimination. Seven patients (35%) responded to desufflation with a sharp transient increase in CO2 elimination, which did not appear to be related to patient age, length of pneumoperitoneum, abdominal pressure, or type of operation.

CONCLUSIONS

During pneumoperitoneum, younger children absorb proportionately more CO2 than older individuals. The short-lived increase in CO2 elimination postdesufflation may be related to an increase in venous return from the lower limbs after release of the abdominal pressure. These findings suggest that small children warrant close monitoring during laparoscopy and during the immediate postoperative period.

Arterial carbon dioxide markedly increases during diagnostic laparoscopy in portal hypertensive children

Several factors are responsible for hypercarbia during laparoscopic procedures. This study was undertaken because we observed a sudden increase in PaCO(2) in children with portal hypertension (PHT), which was unusual in healthy children undergoing laparoscopic procedures. Fifty-seven children underwent laparoscopic procedures under general anesthesia and were mechanically ventilated. Arterial blood samples were obtained 5 min after intubation (T(0)), 15 min and 30 min after CO(2) pneumoperitoneum (T(15) and T(30)), 5 min after desufflation (T(end)), and 10 min after extubation (T(ext)) for blood gas analysis. The changes in PaCO(2), pH, and ETCO(2) were statistically significant during the study periods in both groups (P < 0.05). The percentage of PaCO(2) increase between T(0) and T(15) was 11.5% and 20.1%, respectively, in the control group and the PHT group (P < 0.05). This increase reached 36.8% at T(30) in the PHT group, whereas the control group had a 17.2% increase (P < 0.05). ETCO(2) presented similar changes. The variability in base excess, bicarbonate, PaO(2), arterial oxygen saturation, and SpO(2) was not significant in either group (P > 0.05). The PaCO(2) increased remarkably in children with PHT undergoing laparoscopy, with no difference in intrahepatic or extrahepatic origin. Limiting the duration of CO(2) pneumoperitoneum and intraabdominal pressure and adjusting ventilatory variables to accommodate hypercarbia are of the utmost importance for such cases.

IMPLICATIONS

We compared children with portal hypertension with systemically healthy children during laparoscopy. The increase in arterial and end-tidal CO(2) was remarkable in children with portal hypertension, regardless of bicarbonate changes. Managing ventilation to accommodate hypercarbia is of the utmost importance for such cases.

The reliability of endtidal CO2 in spontaneously breathing children during anaesthesia with laryngeal mask airway, low flow, sevoflurane and caudal epidural

BACKGROUND

Noninvasive devices for monitoring endtidal CO2 (PECO2) are in common use in paediatric anaesthesia. Questions have been raised concerning the reliability of these devices in spontaneous breathing children during surgery. Our anaesthetic technique for elective infraumbilical surgery consists of spontaneous breathing through a Laryngeal Mask Airway (LMA), low fresh gas flow, sevoflurane and a caudal epidural. We wanted to compare PECO2 and arterial CO2 (PaCO2) during surgery.

METHODS

Twenty children, aged 1-6 years, scheduled for infraumbilical surgery, were studied and one arterial sample was taken 45 min after induction of anaesthesia. PECO2, inspiratory PCO2, oxygen saturation, heart rate, respiratory rate, mean arterial blood pressure and expiratory sevoflurane concentration were measured every 5 min. The respiratory and circulatory parameters were stable during surgery.

RESULTS

The mean PaCO2 - PECO2 difference was 0.15 (0.16) kPa [1.1 (1.2 mmHg)].

CONCLUSIONS

PECO2 is a good indicator of PaCO2 in our anaesthetic setting.

Anaesthesia for minimally invasive surgery in children

There continues to be an increase in the applications of minimally invasive surgical techniques in infants and children. This increase includes their use for new surgical procedures as well as their application in younger patients including neonates. As with any new surgical procedure, specific modifications of the anaesthetic technique may be necessary. This chapter reviews (1) the pre-operative evaluation of infants and children scheduled for minimally invasive surgery; (2) techniques for pre-medication and anaesthetic induction; (3) intra-operative anaesthetic implications of laparoscopy, including the cardiorespiratory consequences of CO2 pneumoperitoneum; (4) intra-operative anaesthetic implications of thoracoscopy, including techniques for one-lung ventilation (OLV); and (5) post-operative issues, including pain management and monitoring of cardiorespiratory function as they apply to the patient of paediatric age.