Role of EtCO2 (End tidal CO2) Monitoring (Capnography) During Laparoscopic Surgery under General Anesthesia

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1 ORIGINAL ARTICLE Role of EtCO2 (End tidal CO2) Monitoring (Capnography) During Laparoscopic Surgery under General Anesthesia Mamta G. Patel 1*, V. N. Swadia 2 1 M.D., Associate Professor, 2 M.D., Ex.Professor & Head Department of Anesthesiology, Medical college and S.S.G. Hospital, Vadodara. Gujarat. ABSTRACT BACKGROUND: The rapid development of laparoscopic surgeries demands concurrent advancement in Anesthesthetic techniques and monitoring standards.the laparoscopic surgery requires creation of pneumoperitonium which has detrimental effects on Cardiovascular and Respiratory system. So, vigilant monitoring of ECG,SPO2,NIBP and EtCO2 is mandatory. We studied efficacy and advantages of EtCO2 monitoring in laparoscopic surgery. METHODS & MATERIALS: Total 60 patients belonging to ASAPS-I, II, III posted for various Laparoscopic surgeries were enrolled for the study. Conventional General Anesthesia was administered in all the patients. Monitoring was done in the form of Temperature, Pulse rate, ECG, NIBP, SPO2 and ETCO2 at a regular interval. Variables like Type of surgery, Duration of carboperitonium, Approach, No. of surgical ports, IAP and flow rate of CO2 insufflation were noted down. Increase in EtCO2 level and any complications related to carboperitonium, CO2 insufflation and laparoscopy were also noted. RESULTS: We found that increase in EtCO2 (Hypercarbia) was observed in old age patients, longer duration of pneumoperitonium, extraperitoneal approach and IAP > 16 mm of Hg. The rise in the EtCO2 level was mainly observed 20min after pneumoperitonium. 40% of patients developed hypertension and tachycardia. In 10 cases, subcutaneous emphysema was observed. None of our patient developed fall in SpO2, Pneumothorax or Air embolism. CONCLUSION: The EtCO2 immediately reflects changes in circulatory status and ventilation as well as detects complications during Laparoscopic surgery. Key words: Anaesthesia: GA; Monitoring: Capnography Surgery: Laparoscopic Surgery. INTRODUCTION Advances in laparoscopic surgery have been associated with parallel development in Anesthesia approaches, techniques and monitoring standards. Laparoscopic abdominal surgeries are becoming the preferred technique for surgeries over past decade. Anesthesia for laparoscopic surgery is challenging speciality and Anesthesiologist must constantly improvise and evolve his/her approach in the era of evidence based medicine. Laparoscopic methods depend essentially on the establishment of an intra peritoneal space. A pneumoperitonium using CO2 gas therefore is routinely induced. Although CO2pneumoperitonium (Carboperitonium) has been proved safe and effective in *Corresponding Author: Dr. Mamta G. Patel 6, Yogeshwar Park, Near Swati soc-1, Near Jalaram temple, Manjalpur, Vadodara Contact No: mgpatel111@yahoo.com normal as well as altered pathology, it may be detrimental to cardio respiratory system. Thus, Hemodynamic as well as respiratory monitoring (ECG, NIBP, SPO2, and ETCO2 & Temperature) are mandatory during laparoscopic surgery. Amongst all the monitoring, Capnography has many important and helpful applications during laparoscopic surgery. So, we have decided to study ETCO2 changes during laparoscopy and various Hemodynamic, Respiratory and other effects of pneumoperitonium in the patients posted for laparoscopic surgery. METHODS & MATIREALS After obtaining approval from ethical committee and informed written consent, Total 60 patients posted for various Laparoscopic surgeries were enrolled for the study. Their age ranged from years and weight ranged from kg. The demographic data of the patients are as shown in Table Int J Res Med. 2017; 5(4); e ISSN: p ISSN:

2 Table 1: Demographic Data VARIABLES AGE (Years) years WEIGHT(kg) kg M 19 (31.66%) SEX F 41(68.34%) ASA I 26 (43.34%) ASA II 25 (41.66%) ASA III 09 (15%) After thorough pre anesthetic check up and investigations, all the patients were premedicated using Inj. Tramadol 1-2 mg/kg Inj. Phenargan 0.5 mg/kg and Inj. Glycopyrollate 0.2 mg IM 30 min before surgery. Inj. Midazolam 0.03 mg/kg IV was administered 2 min before induction. Conventional General Anesthesia was administered in all the patients. Baseline and intra operative monitoring was done in the form of Pulse rate, ECG, NIBP, SPO2 and ETCO2. Type of surgery, duration of carboperitonium, extraperitoneal/ intraperitoneal approach, No. of surgical ports, Intra abdominal pressure (IAP) and flow rate of CO2 insufflation were noted down. Monitoring of EtCO2 was done and values were recorded at base line, 5 min after induction, and then 10, 20 and 30 min after pneumoperitonium. Then every hourly EtCO2 was monitored up to the end of surgery and in the immediate post operative period. Maximum level of ETCO2 was also noted down. Haemodynamic monitoring was done vigilantly throughout the surgery. At the end of surgery, patients were reversed with Inj.Neostigmine 50µg/kg IV and Inj. Glycopyrrolate 10µg/kg IV and extubated when the criteria were fulfilled. Any complications related to carboperitonium, CO2 insufflation and laparoscopy were also noted. Statistical analysis was performed using Student s unpaired t-test for demographic data, changes in haemodynamic parameters, O2 saturation and EtCO2. P <0.05 was taken as statistically significant. RESULTS Demographic Data and Type of surgery are as shown in Table-1. Mainly 45% of patients were posted for Laparoscopic Cholecystectomy and for other laparoscopic surgeries are as shown in Table 2. Table 2: Type and Duration of Laparoscopic Surgery Type of surgery 1. Lap. Appendicectomy 12 (20%) 2. Lap. Hernia repair 19 (31.66%) 3. Lap. Cholecystectomy 27 (45%) 4. Lap. Ureterolithotomy 01 (1.67%) Cases (Percentage) 5. Lap. Omentopexy 01 (1.67%) Mean Duration of Surgery min The mean duration of surgery was min in our study. The mean duration of pneumoperitonium, approach, No. of surgical ports and Intra abdominal pressure are as shown in the Table 3. Table 3: Parameters related to pneumoperitonium Duration of pneumoperitonium min Approach Extra peritoneal 19 cases (31.66%) Intra peritoneal 41 cases (68.44%) No. of Surgical ports Three 21(35%) Four 39(65%) Intra abdominal pressure (IAP) of mm Hg Table 4: EtCO2 Level Monitoring. Variables EtCO2 Level (mm of Hg) Baseline min after induction min after carboperitonium min after carboperitonium min after carboperitonium min after carboperitonium Before removal of Trocar Postoperative period EtCO2 monitoring was done at regular interval as seen in Table-4. The rise in the EtCO2 level was mainly observed 20min after the creation of pneumoperitonium. The maximum level of hypercarbia was 85mm of Hg in one case. The range of hypercarbia was found between mm of Hg in our study. (Table-5) Table-5 EtCO2 Level ETCO2 LEVEL NO OF PATIENTS mm of Hg 36 (60 %) mm of Hg 03 (05 %) mm of Hg 16 (26.66 %) mm of Hg 04 (6.66 %) mm of Hg 01 (1.66 %) Table 6: Changes in Pulse rate Variables Pulse Rate / Min (Mean + SD) Baseline min after induction min after pneumoperitonium min after pneumoperitonium min after pneumoperitonium hour after pneumoperitonium hour after pneumoperitonium After removal of Trocar Postoperative period Int J Res Med. 2017; 5(4); e ISSN: p ISSN:

3 Haemodynamic parameters were monitored vigilantly. As shown in Table 6, rise in pulse rate from baseline was observed in 45% of patients. Tachycardia (PR >100/min) was observed in 35% of patients who developed hypercarbia. Cardiac arrhythmias were found in 3 cases which was associated with high EtCO2 level (i.e. 60, 75 and 80 mm of Hg). Rise in Mean blood pressure was found in 40% of patients. Hypertension (BP > 140/90 mm of Hg) was detected in 40% of patients. The changes in systolic and diastolic blood pressure in our study are shown in Graph1 and Graph 2. Graph 1: Changes in Systolic blood pressure mm of Hg systolic blood pressure B AS E L INE B F.P NE U 15MIN 30MIN MAX. V AL AF T.TR OC Dura tion Graph 2: Changes in Diastolic Blood pressure Dias tolic blood pres s ure mm of Hg B AS E L INE B F.P NE U 15MIN 30MIN MAX. V AL AF T.TR OC Dura tion O2 saturation remained within normal limits in all the patients. The complications related to carboperitonium or CO2 insufflation are observed as shown in Table 7. Table7: Complications during Laparoscopy [A] Related to Pneumoperitonium 1. cardiac arrhythmias 03 (5%) 2. Hypotension 02 (3.33%) 3. Hypertension 40 (66.66%) 4. Hypercarbia 35 (58.33%) 5. Gas embolism Subcutaneous emphysema 10 (16.66%) 7. Pneumothorax [B] Post operative period 1. Nausea & Vomiting 21(35%) 2. DVT None of the patient in our study developed any serious complication related to carboperitonium. The course of anesthesia was uneventful in all the cases in our study. Graph 3: A Normal Capnogram DISCUSSION Over the last decade, key hole surgery has taken over the whole scenario of surgical speciality. Laparoscopic surgery has been used increasingly and becoming the preferred technique. It requires insufflation of gas. The CO2 pneumoperitonium and Trendelenburg position can cause serious physiological changes in cardio respiratory system. Adequate monitoring of haemodynamics, SpO2 and EtCO2 are mandatory during laparoscopy. 1 Capnography provides valuable information about changes in PaCO2. It has mainly three important applications in Laparoscopy. It serves as a non invasive monitor of PaCO2 during carboperitonium It helps to maintain ventilatory pattern It helps in detection of complications of CO2 insufflation such as Pneumothorax, Haemorrhage, Air embolism etc 2,3 Therefore, we decided to monitor ETCO2 during laparoscopic surgery in total 60 patients. We studied various parameters related to hypercarbia due to carboperitonium like Age, ASA status, Type and duration of laparoscopic surgery, duration and approach of carboperitonium, IAP, no of ports etc. We also observed hemodynamic and respiratory changes as well as O2 saturation during laparoscopic surgery. Age of the patient: In our study, mean age was found years. The changes like hypercarbia, tachycardia, hypertension due to CO2 pneumoperitonium were mainly observed in 20% of patients (>60 years) in our study. Sood Jayashree and Bhavani Shankar et al also found that 150 Int J Res Med. 2017; 5(4); e ISSN: p ISSN:

4 various changes due to carboperitonium were found mainly in older patients. 1, 2 ASAPS of patient: In our study, mainly 85 % of patients belonged to ASAPS I and II. Only 15% of patients were at risk III. Bhavani Shankar had observed that ETCO2 monitoring is reliable in predicting PaCo2 in healthy ASA I and II subjects and elderly patients. 3 However, in ASA III and IV patients, PETCO2 may not reflect changes in PACO2 during insufflation. In our study, two patients of the AR-III group developed hypercarbia without any complications. Type of laparoscopic surgery: Total 27 patients in our study were mainly posted for Laparoscopic cholecystectomy surgery. Among them, 12 patients developed rise in EtCO2. Wolf Js 4 has observed that increase in ETCO2 also depends on Type of surgery like cholecystectomy as well as degree of dissection around the diaphragm and in the retroperitoneal space. 2, 5 Duration of surgery: Duration of surgery was found min in our study. In two patients during laparoscopic cholecystectomy surgery, the operative time was prolonged up to 180 and 200 min and ETCO2 level was observed 75and 80 mm of Hg respectively. Immediate treatment with hyperventilation and release of CO2 pneumoperitonium was instituted in such patients.etco2 Level came to normal 30 min after the release of carboperitonium. Cynthia M. et al suggested that operative time greater than 200 minutes may predispose patients to hypercarbia and development of subcutaneous emphysema during laparoscopy. 4 Duration of Carboperitonium: Similarly, duration of pneumoperitonium also affects EtCO2 level. In our study, the mean duration was min. (Range- 25 to 150 min). Cynthia et al and Gutt C.N. et al suggested that hypercarbia is always associated with longer duration of surgery more than 180 min as well as carboperitonium more than 120 min. 4, 5 Intraperitoneal or Extraperitoneal Approach: In our study, in (68.44%) % of patients, laparoscopy was done using Intra peritoneal approach, while in (31.66%) % of patients, extraperitoneal approach was used. Among them, 15% and 20% of patients developed hypercarbia (EtCO2 > 55 mm of Hg) in Intra peritoneal and extraperitoneal approach respectively. Hypercarbia and changes due to carboperitonium was mainly observed in extraperitoneal approach of laparoscopic surgery. Cynthia et al had also observed the similar correlation between hypercarbia and extraperitoneal approach. 4, 5 Also Several authors have established a link between extraperitoneal insufflation and extensive dissection with development of subcutaneous emphysema and resultant hypercarbia. 4,5,6 The maximum level of hypercarbia i.e. 80 mm of Hg was observed in one case during laparoscopic Hernia repair using extraperitoneal CO2 insufflation in our study. No. of surgical ports: We found from our study that, No. of surgical ports were three in 35% patients and Four in 65% cases. Cynthia M. et al had suggested that increased no of operative ports (>6) were significantly associated with development of hypercarbia and subcutaneous emphysema. 4 Gutt C.N et al found that an increase in no. of ports increases the no. of points of entry of CO2 gas into the subcutaneous tissue. 5 However in our study, no correlation was found between no. of surgical ports and hypercarbia because none of patients had more than 4 ports. Intra abdominal pressure (IAP): We observed Mean Intra abdominal pressure (IAP) of mm Hg in our study. In two cases, IAP was 16 mm of Hg which was associated with hypercarbia (EtCO2 was 58 and 55 mm of Hg). Many authors have observed that increase in IAP during laparoscopy was associated with increase in EtCO2 levels. IAP has a major role in the development of hypercarbia since it both increases the absorption and decreases the exhaustion of CO2. 7,8 Furthermore, increased IAP during carboperitonium triggers several pathophysiological mechanisms, sympathetic stress response and decrease 151 Int J Res Med. 2017; 5(4); e ISSN: p ISSN:

5 in cardiac output and hypotension. Motew et al showed that complications do not occur until IAP exceeds 20 mm of Hg. 1 Volker R.J. et al showed that an increase in IAP above a defined acceptable pressure can have multiple effects on haemodynamics, blood flow or ventilation. He suggested that IAP of less than mm of Hg is adequate. 7 Therefore, a flexible adjustment of IAP, preferably below 12 mm of Hg maximum is advisable. Continuous EtCO2 monitoring: EtCO2 monitoring was done as shown in table 4.We found that rise in EtCO2 from baseline mainly started 20 min after creation of carboperitonium. Hypercarbia (EtCO2 level >55mm of Hg) was observed in 35 % patients in our study. The maximum level of EtCO2 was found at 80 mm of Hg in one patient posted for laparoscopic hernia repair. As Cynthia et al suggested that Increase in EtCO2 was observed in prolonged operative time (180 to 300 min), extraperitoneal approach, old aged patients, increased IAP (16 mm of Hg) and in patients who developed subcutaneous emphysema. 4,5,6,7 Our observations are correlated with their studies. Hemodynamic changes in relation to Hypercarbia: The cardiovascular system is one of the most challenged systems of human body during laparoscopy. In our study, no change in Pulse rate and Blood pressure was observed in 60% of patients. Hypertension and associated tachycardia were observed in 40% cases in whom hypercarbia was developed. Cardiac arrhythmias were observed in 3 patients with increased EtCO2 level. Changes in CV system occurring during CO2 pneumoperitonium result from two main factors- hypercarbia (and subsequent acidosis) and increased Intra Abdominal Pressure (IAP). 1 Hypercarbia and acidosis can cause hemodynamic changes by direct action on CV system and by indirect action through sympathoadrenal stimulation. The direct effect of CO2 decreases cardiac contractility, sensitization of myocardium to the arrythmogenic effects of catecholemines and systemic vasodilatation. Compensatory tachycardia and vasoconstriction occurs. 4,5 So, meticulous EtCO2 monitoring along with NIBP, ECG and SpO2 monitoring is essential and mandatory for safe conduct of Laparoscopic procedures and should be used to detect arrhythmias, hemodynamic changes and gas embolism. Chopra Guarav et al have suggested that, any sudden decrease in cardiac output (C.O.) leads to a decrease in EtCO2 concentration. Thus, the capnograph can be used as a cardiac output monitor. 9 Preoperative IV loading (10 ml/kg), prompt detection and management of CVS complications, slow insufflation of CO2 and low IAP are required for prevention of CV complications during laparoscopy. Also, extreme positioning of patient during surgery is to be avoided. 1 Pulmonary changes: Another system involve in laparoscopy is respiratory system. EtCO2 as well as SpO2 monitoring are helpful in laparoscopy surgery. In our study, No change in SPO2 was observed in all the cases. SpO2 remained within normal limits (97-100%) in all the patients. Emphysema & Hypercarbia: Cynthia et al suggested that subcutaneous emphysema caused by CO2 insufflation results in increased CO2 absorption through subcutaneous tissues with a final outcome of hypercarbia and increased EtCO2 level. 4 In our study, this type of association between subcutaneous emphysema and hypercarbia was observed in 16.66% patients. Rise in EtCO2 was ranged from 55 to 80 mm of Hg. Hypoxia, barotraumas, gas embolism, subcutaneous emphysema, pneumothorax and pneumomediastinum are distinct complications of laparoscopy. 1 EtCO2 monitoring helps in early detection of pulmonary complications and its management and prompt treatment. 2, 3 Cynthia et al suggested that risk factors for the development of pulmonary complications are ETCO2 50 mm of Hg, operating time >200 min, patient s age over 65 years, multiple ports, increased 152 Int J Res Med. 2017; 5(4); e ISSN: p ISSN:

6 IAP etc. They also suggested that, clinically significant cases can be predicted by prolonged operative time and elevated maximum EtCO2 level. 4 We used manual controlled ventilation in all the cases in our study. According to many studies, capnography can be helpful for the ventilator settings during controlled ventilation in laparoscopy. They suggested that, the typical desired normal EtCO2 concentration under General anesthesia is mm of Hg. During Laparoscopic surgery, EtCO2 values of mm of Hg are common findings. 1,4,5,8 Increase in minute ventilation using higher pressure helps to maintain EtCO2 level in laparoscopy. Thus, Capnograph is usually considered a ventilation monitor with relatively constant tidal volume as with a ventilator. The Graph-3 shows normal capnogram. Gutt C.N et al also concluded that capnography proved to be an excellent guide to adjust ventilation during CO2 insufflation. 5 Subcutaneous emphysema was developed in 10 cases in our study. None of our patient developed either pneumothorax or pneumomediastinum or gas embolism. In the study of Cynthia et al, incidences of pulmonary complications were observed. According to them, out of 968 laparoscopies, 53(5.5%) cases had developed hypercarbia, 22 (2.3%) cases of subcutaneous emphysema and 19(1.9%) cases of pneumothorax were observed. 4 Air embolism was not observed in any of the case in our study. David Shulman had reported a case of CO2 embolism during laparoscopy. Capnography had detected the embolism. He recommended continuous monitoring of capnography and heart sounds routinely which may provide information that will assist Anesthetist in making early diagnosis of gas embolism and its prompt treatment. The study by Shulman et al suggested that the capnography may be the earliest of the standard monitors to detect a fatal venous air embolism. 8 Thus, Continuous and careful monitoring of EtCO2 by Capnography is a useful and effective noninvasive monitoring technique in anesthesia for laparoscopy. The EtCO2 immediately reflects changes in circulatory status (Tachycardia and/or Arrhythmias, hypertension) and ventilation as well as detects complications related to CO2 pneumoperitonium (Hypercarbia, Subcutaneous emphysema, Gas embolism, Pneumothorax etc.) during laparoscopic surgery. The EtCO2 monitoring immediately reflects changes in circulatory status and ventilation as well as it detects complications during Laparoscopic surgery. Thus, EtCO2 monitoring is mandatory and essential monitoring during laparoscopic surgery for the safe conduct of general anesthesia. REFERENCES 1. Sood Jayashree and Jain Anil Kumar. Anaesthesia in Laparoscopic Surgery.Firstedition,2007.(Jaypee).Pg no.34,57,58,69,70,120,138, Bhavani Shankar K, Moseley H, Kumar Y, Delph Y. Capnometry and anaesthesia. Can.J Anaesth 1992;39:6: Bhavani Shankar Kodali. Capnography and anaesthesia on website launched by Bhavani Shankar Kodali on August 2001 and updated on 25 August Cynthia M. Murdock, Armand J. Wolff and Thomas Van Geem. Risk factors for Hypercarbia, Subcutaneous Emphysema, Pneumothorax and Pneumomediastinum During Laparoscopy. Obstetrics& Gynecology 2000;95: Gutt C.N, Oniu T, Mehrabi A, Schemer P, Kashfi A, Kraus T et al. Circulatory and Respiratory Complications of Carbon Dioxide Insufflation. Digestive surgery 2004; 21: Murray Bosseau W. Monitoring Devices and Anesthesia for Laparoscopic Surgery. Laparoscopy Today 2005; 2: Volker R. Jecobs, Morrison John, kiechle Marion. Twenty-five simple ways to increase insufflation 153 Int J Res Med. 2017; 5(4); e ISSN: p ISSN:

7 performance and patient safety in Laparoscopy. The journal of the American Association of Gynecologic Laparoscopists. August 2004; 11:3: Shulman David. Capnography in the early diagnosis of carbon dioxide embolism during laparoscopy. Can Anaesth soc J 1984;31:4: Chopra Guarav, Singh Dhananjay Kumar, Jindal Parul, Sharma U.C., Sharma J.P. Haemodynamic, end-tidal carbon dioxide, saturated pressure of oxygen and electrocardiogram changes in laparoscopic and open cholecystectomy: A comparative clinical evaluation. The Internet Journal of Anesthesiology ISSN: X 154 Int J Res Med. 2017; 5(4); e ISSN: p ISSN: