Respiratory compliance during laparoscopic hiatal and inguinal hernia repair

The Effect of Intra-abdominal Pressure on Heart Rate Variability and Hemodynamics During Laparoscopic Cholecystectomy: A Prospective Observational Study

Introduction This study aimed to evaluate hemodynamic changes using heart rate variability (HRV) measurements in diabetic and nondiabetic patients who will undergo laparoscopic cholecystectomy and to provide our preoperative measurements to guide us for better perioperative anesthesia management. Materials and methods The study included 143 patients aged 40 years and older who would undergo elective laparoscopic surgery, did not have any comorbidities other than diabetes mellitus (DM) type II, and were in the American Society of Anesthesiologists (ASA) class I-III risk group. Patients were divided into two groups: the control group (n = 77) and the DM group (n = 66). The preoperative glycated hemoglobin (HbA1C) level was measured. Peripheral oxygen saturation (SpO2) and hemodynamic parameters such as systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), and HRV parameters were measured preoperatively, perioperatively, and postoperatively. Intra-abdominal pressure (IAP) was administered at 10-12 mmHg. Results Even though SAP, DAP, MAP, and HR decreased with induction, they increased with insufflation, and an overall decrease was seen at the postoperative 24th hour for all parameters. When the groups were evaluated, no difference was observed except that the DAP was significantly lower in the DM group (p = 0.029) at insufflation and the HR was higher in the DM group at induction, and the difference was significant (p = 0.001). Preoperative HRV parameters were significantly lower in the DM group. According to the HRV parameters, although a decrease was observed after induction and insufflation, conversely, an increase was observed postoperatively. When the postoperative and preoperative values were compared, the standard deviation of the NN (R-R) intervals (SDNN), SDNN index, high frequency (HF), low frequency (LF), and LF/HF parameters were found to be significantly lower in the DM group than in the control group. Conclusion Diabetic patients are more sensitive to increased intra-abdominal pressure (IAP) in laparoscopic surgery, and the effects on cardiac autonomic functions can be determined by HRV measurements without clinically reflecting on hemodynamic data. Additionally, in diabetic patients with preoperative LF and/or HF values less than 100, we believe that careful follow-up in terms of autonomic neuropathy complications and anesthesia management should be done more meticulously in these patients.

Respiratory function during anesthesia: effects on gas exchange

Anaesthesia causes a respiratory impairment, whether the patient is breathing spontaneously or is ventilated mechanically. This impairment impedes the matching of alveolar ventilation and perfusion and thus the oxygenation of arterial blood. A triggering factor is loss of muscle tone that causes a fall in the resting lung volume, functional residual capacity. This fall promotes airway closure and gas adsorption, leading eventually to alveolar collapse, that is, atelectasis. The higher the oxygen concentration, the faster will the gas be adsorbed and the aleveoli collapse. Preoxygenation is a major cause of atelectasis and continuing use of high oxygen concentration maintains or increases the lung collapse, that typically is 10% or more of the lung tissue. It can exceed 25% to 40%. Perfusion of the atelectasis causes shunt and cyclic airway closure causes regions with low ventilation/perfusion ratios, that add to impaired oxygenation. Ventilation with positive end-expiratory pressure reduces the atelectasis but oxygenation need not improve, because of shift of blood flow down the lung to any remaining atelectatic tissue. Inflation of the lung to an airway pressure of 40 cmH2O recruits almost all collapsed lung and the lung remains open if ventilation is with moderate oxygen concentration (< 40%) but recollapses within a few minutes if ventilation is with 100% oxygen. Severe obesity increases the lung collapse and obstructive lung disease and one-lung anesthesia increase the mismatch of ventilation and perfusion. CO2 pneumoperitoneum increases atelectasis formation but not shunt, likely explained by enhanced hypoxic pulmonary vasoconstriction by CO2. Atelectasis may persist in the postoperative period and contribute to pneumonia.

Effects of pneumoperitoneal pressure and position changes on respiratory mechanics during laparoscopic colectomy

Background

This study was designed to assess the effects of pneumoperitoneal pressure (PP) and positional changes on the respiratory mechanics during laparoscopy assisted colectomy.

Methods

Peak inspiratory pressure, plateau pressure, lung compliance, and airway resistance were recorded in PP of 10 mmHg and 15 mmHg, with the position change in 5 steps: head-down at 20°, head-down at 10°, neutral position, head-up at 10° and head-up at 20°.

Results

When the patient was placed head-down, the position change accentuated the effects of pneumoperitoneum on respiratory mechanics. However, when the patient was placed in a head-up position during pneumoperitoneum the results showed no pattern. In the 20° head-up position with the PP being 10 mmHg, the compliance increased from 30.6 to 32.6 ml/cmH₂O compared with neutral position (P = 0.002). However with the PP being 15 mmHg, the compliance had not changed compared with neutral position (P = 0.989). In 20° head-down position with the PP of 10 mmHg, the compliance was measured as 24.2 ml/cmH₂O. This was higher than that for patients in the 10° head-down position with a PP of 15 mmHg, which was recorded as 21.2 ml/cmH₂O. Also in the airway resistance, the patient in the 20° head-down position with the PP of 10 mmHg showed 15.8 cmH₂O/L/sec, while the patient in the 10° head-down position with the PP of 15 mmHg showed 16.2 cmH₂O/L/sec of airway resistance. These results were not statistically significant but still suggested that the head-down position accentuated the effects of pneumoperitoneum on respiratory mechanics.

Conclusions

Our results suggest that respiratory mechanics are affected by the patient position and the level of PP - the latter having greater effect.

A randomized crossover study to determine the effect of a 30° head-up versus a supine position on the functional residual capacity of term parturients

BACKGROUND

Airway management continues to pose challenges to the obstetric anesthesiologist. Functional residual capacity (FRC), which acts as an oxygen reservoir, is reduced from the second trimester onwards and is exacerbated in the supine position. Mechanisms to increase FRC may delay the onset of hypoxemia during periods of apnea. Values for changes in FRC in term parturients in semierect positions are unknown. We hypothesized that the FRC of healthy term parturients would increase significantly in the 30° head-up position in comparison with the supine position.

METHODS

Twenty-two healthy term parturients were recruited. Initial screening spirometry was performed to exclude undiagnosed respiratory disease. FRC was measured using the helium dilution technique in the supine, 30° head-up, and sitting erect positions. Subjects were randomized to sequence of position testing order. Noninvasive systolic blood pressure, heart rate, and oxygen saturation were measured twice in each testing position.

RESULTS

Results from 20 subjects were analyzed. The spirometry results for all subjects were within predicted normal reference intervals. FRC measurements differed significantly (P<0.001) among all positions. FRC increased by a mean of 188 mL (95% confidence interval 18 to 358 mL) from the supine to the 30° head-up position (P=0.03). There were no significant differences in vital signs among testing positions (P>0.16).

CONCLUSIONS

We have demonstrated that the FRC of healthy term parturients increases significantly in the 30° head-up position in comparison with supine.

Effects of pneumoperitoneum and positioning on respiratory mechanics in chronic obstructive pulmonary disease patients during Nissen fundoplication

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate the effects of pneumoperitoneum and patient positioning on respiratory mechanics and blood gases in chronic obstructive pulmonary disease (COPD) patients during laparoscopic Nissen fundoplication.

METHODS

After the approval of the Ethical Committee, 32 patients were divided into 2 groups as COPD patients (n=16) and normal patients (n=16). Dynamic respiratory compliance (Cdyn), airway resistance, and peak inspiratory pressure were monitored. Measurements were made in 5 time points: after intubation (intubation), Trendelenburg position (Trendelenburg), during laparoscopic Nissen fundoplication surgery after pneumoperitoneum with the Fowler position (Fowler), right before the desufflation with Fowler position (Fowler-end), and after the desufflation in supine position (supine). Samples of arterial blood gases were collected at the same periods.

RESULTS

At all periods, there was a significant decrease in Cdyn and arterial oxygen pressure in 2 groups. Although pneumoperitoneum did not exist during Trendelenburg position, the Cdyn (38+/-13 mL cm H2O(-1)) found to be significantly decreased in COPD patients. In 2 groups, the lowest Cdyn value detected during the Fowler-end period was 43+/-8 mL cm H2O(-1) in control group and 34+/-11 mL cm H2O(-1) in COPD group. Whereas the pH decreased at Fowler, Fowler-end, and supine period, arterial carbon dioxide pressure increased (P<0.05). There was no difference for the other parameters.

CONCLUSIONS

In COPD patients, Trendelenburg position has negative effect on respiratory mechanics. Pneumoperitoneum and other positions have similar effect on respiratory mechanics in COPD and control patients.

Tolerance of laparoscopy and thoracoscopy in neonates

OBJECTIVES

Video-surgery in neonates is recent. Data on the respiratory, hemodynamic, and thermic effects during the first month of life are still sparse. This study aimed to evaluate the tolerance of video-surgery in neonates and to determine the risk factors of per-operative complications.

METHODS

From 1994 to 2004, 49 neonates (mean age: 11 days; weight: 3285 g) underwent 50 video-surgical procedures. Indications for laparoscopy were duodenal atresias, volvulus with malrotation, pyloric stenosis, gastroesophageal reflux, cystic lymphangiomas, ovarian cysts, biliary atresia, and congenital diaphragmatic hernias; indications for thoracoscopy were esophageal atresias and tracheoesophageal fistula.

RESULTS

Median operative time was 79 minutes. Mean insufflation pressure was 6.7 mm Hg (range: 3-13). Oxygen saturation decreased, especially with thoracic insufflation or high-pressure pneumoperitoneum. Systolic arterial pressure, which decreased in 20% of the patients, was controlled easily with vascular expansion. Thermic loss (mean postoperative temperature: 35.6 degrees C) was proportional to the duration of insufflation. No surgical incident was noted. Ten anesthetic incidents occurred (20%), 3 of which required temporary or definitive interruption of insufflation (O2 saturation <70%). Risk factors for an incident were low preoperative temperature, high variation of end-tidal pressure of CO2, surgical time >100 minutes, thoracic insufflation, and a high oxygen or vascular expansion requirement at the beginning of insufflation.

CONCLUSION

The neonate's high sensitivity to insufflation is an important limiting factor of video-surgery. The described profile of the neonate at risk may help to reduce the frequency of adverse effects of this technique and improve its tolerance.

The effect of low-flow sevoflurane and desflurane on pulmonary mechanics during laparoscopic surgery

BACKGROUND

This study was designed to investigate the effects of inhaled anesthetic agents on respiratory mechanics with low flow anesthesia in laparoscopic abdominal surgery. Two inhaled anesthetics, desflurane and sevoflurane, have a lower solubility in blood and tissues than all previous volatile anesthetics, and have become the preferred volatile anesthetics for routine surgical procedures.

METHODS

Twenty-six patients were examined. Patients were randomly assigned to two groups, to receive sevoflurane (n = 13) or desflurane (n = 13). Tidal volume and ventilation rate were kept unchanged throughout the operation. Intra-abdominal pressure was kept constant at the level of 12 mm Hg. Respiratory mechanics such as peak inspiratory pressure (PIP), respiratory resistance (Rr), and dynamic compliance (Cdyn) measurements were recorded by a Datex-Ohmeda respiratory device (Datex-Ohmeda, Finland) at four timepoints: 5 minutes after mechanical ventilation started (T1), after insufflation of the peritoneum (T2), in the 30-degree Trendelenburg position (T3), and after desufflation of the peritoneum (T4).

RESULTS

In our study, desflurane caused a statistically significant increase in PIP and Rr and decrease in C(dyn). When the two groups were compared, Rr values in the deslurane group showed significant increases at T2, T3, and T4 compared to the sevoflurane group (P < 0.05). These values did not change in the sevoflurane group, while PIP significantly increased at T2, T3, and T4 after desufflation in the desflurane group (P < 0.05). Cdyn values decreased significantly at all 4 timepoints in the desflurane group compared to the sevoflurane group (P < 0.05).

CONCLUSION

We concluded that respiratory mechanics were affected by desflurane with low flow anesthesia in patients undergoing laparoscopic abdominal surgery. No significant influence on respiratory mechanics was seen with sevoflurane anesthesia.

Anaesthetic considerations for laparoscopic cholecystectomy

Minimally invasive surgical procedures aim to minimize the trauma of the interventional process but still achieve a satisfactory therapeutic result. Tissue trauma is significantly less than that with conventional open procedures, offering the advantages of reduced post-operative pain, shorter hospital stay, more rapid return to normal activities and significant cost savings. Laparoscopic cholecystectomy is now a routinely performed procedure and has replaced conventional open cholecystectomy as the procedure of choice for symptomatic cholelithiasis. Public expectation and developments in instrumentation have fuelled this change. The physiological effects of intraperitoneal carbon dioxide insufflation combined with variations in patient positioning can have a major impact on cardiorespiratory function, particularly in elderly patients with co-morbidities. Intra-operative complications may include traumatic injuries associated with blind trocar insertion, gas embolism, pneumothorax and surgical emphysema associated with extraperitoneal insufflation. Appropriate monitoring and a high index of suspicion can result in early diagnosis of, and treatment of, complications. Laparoscopic cholecystectomy has proven to be a major advance in the treatment of patients with symptomatic gallbladder disease.

Influence of pneumoperitoneum and patient positioning on respiratory system compliance

STUDY OBJECTIVE

To investigate the influence of pneumoperitoneum (PP) and posture on respiratory compliance and ventilation pressures.

DESIGN

Prospective, single blind trial.

PATIENTS

10 female ASA physical status I and II patients scheduled for elective gynecologic laparoscopy.

SETTING

University medical center.

INTERVENTIONS

Anesthesia was performed as total IV anesthesia (TIVA) with propofol, alfentanil, and atracurium. After induction of anesthesia and orotracheal intubation, the lungs were ventilated to maintain partial pressure of CO(2) (P(ET)CO(2)) of 30 +/- 3 mmHg. Ventilation was kept constant. As gas mixture oxygen and air 1:1 was used without positive end-expiratory pressure (PEEP).

MEASUREMENTS

Measurements were taken before and after creation of pneumoperitoneum with an intraabdominal pressure (IAP) of 10 mmHg, of 15 mmHg in 20 degrees head-down tilt, then in 20 degrees head-up tilt, and after deflation of PP. We determined peak inspiratory pressure (PIP), mean airway pressure (mPaw), P(ET)CO(2), expiratory minute volume (V(E)), heart rate (HR), and systolic (SBP), diastolic (DBP), and mean arterial pressure (MAP). Respiratory system compliance (C(eff rs)) was calculated as quotient of tidal volume (V(T)) and PIP.

MAIN RESULTS

After creation of PP (IAP 10 mmHg), there was a significant increase of median PIP (3 cmH(2)O), mPaw (1 cm H(2)O) and arterial pressure (BP), (MAP by 7 mmHg), C(eff rs) decreased by 6 mL. cm H(2)O(-1). Increase of IAP to 15 mmHg led to a further increase of PIP (2 cm H(2)O) and mPaw (1 cm H(2)O), and a further decrease of C(eff rs) by 5 mL cm H(2)O(-1); BP decreased (MAP by 5.5 mmHg). Head-up or head down positions showed no significant hemodynamic or pulmonary changes. P(ET)CO(2)increased from 29.5 to 36 mmHg at an IAP of 15 mmHg, but then no further changes were noticed. Five minutes after deflation of pneumoperitoneum all values returned to baseline levels.

CONCLUSIONS

Creation of PP at an IAP of 15 mmHg reduced respiratory system compliance, and increased peak inspiratory and mean airway pressures, which quickly returned to normal values after deflation. Head-down or head-up position did not further alter those parameters.

Physiologic changes during laparoscopy

The short-term benefits of minimal access techniques include less pain, early mobilization, and shorter hospital stay. Nonetheless, significant data have accumulated regarding the complications associated with laparoscopic techniques, including those that are unique to laparoscopic surgery such as bile duct injury and disruption of major blood vessels. Other problems such as myocardial ischemia and respiratory acidosis are associated with the cardiopulmonary effects of pneumoperitoneum and systemic CO2 absorption. These physiologic changes, although tolerated by healthy patients, could have particular adverse consequences for infirm and critically ill patients. It would appear that minimizing IAP during insufflation decreases the risk of potentially marked cardiovascular changes and regional blood flow alterations. In turn, this could arguably decrease the risk of perioperative myocardial events, or organ dysfunction or failure. Laparoscopy in the critically ill patient is questionable because the role is not established. An ICU patient has little to gain from the benefits of early mobilization. Conversely, in the presence of raised ICP or borderline organ function, the physiologic changes associated with pneumoperitoneum and laparoscopy could have profound detrimental effects.

Inert gas exchange during pneumoperitoneum at incremental values of positive end-expiratory pressure

Laparoscopy is a surgical technique for a growing variety of abdominal operations. In patients undergoing this procedure, arterial blood oxygenation and hemodynamics are frequently depressed. This study evaluated the effect of different levels of positive end-expiratory pressure (PEEP) during intraperitoneal CO(2) insufflation on the lung's ventilation-perfusion distribution in a porcine model. We studied 13 anesthetized pigs with an intraperitoneal pressure of 15 cm H(2)O applied at either incremental values of PEEP (5-20 cm H(2)O, increments of 5 cm H(2)O) or a constant PEEP of 5 cm H(2)O. The effects of CO(2) pneumoperitoneum on inert gas exchange and hemodynamics were examined with the multiple inert gas elimination technique. During pneumoperitoneum, gas exchange was most augmented by 15 and 20 cm H(2)O of PEEP. Although the differences in hemodynamics between the individual settings were insignificant, 10 cm H(2)O of PEEP provided the smallest impairment of hemodynamics. We conclude that PEEP of 15 H(2)O during pneumoperitoneum resulted in a modest hemodynamic depression but significant gas exchange augmentation in our experiment.

IMPLICATIONS

Anesthetized pigs, with a pneumoperitoneum of 15 cm H(2)O, were treated either with incremental values of positive end-expiratory pressure (5-20 cm H(2)O, increments of 5 cm H(2)O) or with a constant positive end-expiratory pressure of 5 cm H(2)O. Fifteen and 20 cm H(2)O resulted in significantly improved pulmonary gas exchange compared with 5 cm H(2)O.