Introduction of laparoscopic nephrectomy for autosomal dominant polycystic kidney disease as the standard procedure.

PURPOSE: Autosomal dominant polycystic kidney disease (ADPKD) is a common hereditary disorder and accounts for 5-10% of all cases of kidney failure. 50% of ADPKD patients reach kidney failure by the age of 58 years requiring dialysis or transplantation. Nephrectomy is performed in up to 20% of patients due to compressive symptoms, renal-related complications or in preparation for kidney transplantation. However, due to the large kidney size in ADPKD, nephrectomy can come with a considerable burden. Here we evaluate our institution's experience of laparoscopic nephrectomy (LN) as an alternative to open nephrectomy (ON) for ADPKD patients. MATERIALS AND METHODS: We report the results of the first 12 consecutive LN for ADPKD from August 2020 to August 2021 in our institution. These results were compared with the 12 most recent performed ON for ADPKD at the same institution (09/2017 to 07/2020). Intra- and postoperative parameters were collected and analyzed. Health related quality of life (HRQoL) was assessed using the SF36 questionnaire. RESULTS: Age, sex, and median preoperative kidney volumes were not significantly different between the two analyzed groups. Intraoperative estimated blood loss was significantly less in the laparoscopic group (33 ml (0-200 ml)) in comparison to the open group (186 ml (0-800 ml)) and postoperative need for blood transfusion was significantly reduced in the laparoscopic group (p = 0.0462). Operative time was significantly longer if LN was performed (158 min (85-227 min)) compared to the open procedure (107 min (56-174 min)) (p = 0.0079). In both groups one postoperative complication Clavien Dindo ≥ 3 occurred with the need of revision surgery. SF36 HRQol questionnaire revealed excellent postoperative quality of life after LN. CONCLUSION: LN in ADPKD patients is a safe and effective operative procedure independent of kidney size with excellent postoperative outcomes and benefits of minimally invasive surgery. Compared with the open procedure patients profit from significantly less need for transfusion with comparable postoperative complication rates. However significant longer operation times need to be taken in account.

Operating room time savings in Germany- and UK-based hospitals with 3D- VS. 2D-imaging technology in laparoscopic surgery: Meta analysis and budget impact model - Health economic evaluation.

AIMS: Opportunity cost (OC) analysis is key when evaluating surgical techniques. Operating room (OR) time is one potential source of OC in laparoscopic surgery. This study quantifies differences in OR time between 3D- and 2D-imaging technology in laparoscopic surgery, translates these into OC and models the economic impact in real-world hospitals. METHODS: First a systematically performed literature review and meta-analysis were conducted. Then, methods to translate OR time savings into OC were theorised and a budget impact model was created. After that, the potential time savings of real-world hospital case mixes were extrapolated. Finally, the opportunity costs of not using 3D-imaging in laparoscopic surgery were evaluated. RESULTS: Average OR time saving per laparoscopic procedure was -19.4 min (-24.3; -14.5) (-14%) in favour of 3D. The Budget Impact Model demonstrated an economic impact of using 3D-laparoscopy instead of 2D laparoscopy, ranging from £183,045-£866,316 in the British and 73,049€-437,829€ in German hospitals, modelling a mixture of cost savings and performing additional procedures (earning additional revenue). CONCLUSION: The OC analysis revealed significant economic benefits of introducing 3D-imaging technology in laparoscopic surgery, on the basis that average procedure time is reduced. Utilising the saved OR time to perform additional procedures was the biggest driver of OC. Hospital case mix and procedure volume indicated the magnitude of the OC.

Navigated laparoscopic microwave ablation of tumour mimics in pig livers: a randomized ex-vivo experimental trial.

BACKGROUND: In order to efficiently perform laparoscopic microwave ablation of liver tumours precise positioning of the ablation probe is mandatory. This study evaluates the precision and ablation accuracy using the innovative laparoscopic stereotactic navigation system CAS-One-SPOT in comparison to 2d ultrasound guided laparoscopic ablation procedures. METHODS: In a pig liver ablation model four surgeons, experienced (n = 2) and inexperienced (n = 2) in laparoscopic ablation procedures, were randomized for 2d ultrasound guided laparoscopic or stereotactic navigated laparoscopic ablation procedures. Each surgeon performed a total of 20 ablations. Total attempts of needle placements, time from tumor localization till beginning of ablation and ablation accuracy were analyzed. RESULTS: The use of the laparoscopic stereotactic navigation system led to a significant reduction in total attempts of needle placement. The experienced group of surgeons reduced the mean number of attempts from 2.75 ± 2.291 in the 2d ultrasound guided ablation group to 1.45 ± 1.191 (p = 0.0302) attempts in the stereotactic navigation group. Comparable results could be observed in the inexperienced group with a reduction of 2.5 ± 1.50 to 1.15 ± 0.489 (p = 0.0005). This was accompanied by a significant time saving from 101.3 ± 112.1 s to 48.75 ± 27.76 s (p = 0.0491) in the experienced and 165.5 ± 98.9 s to 66.75 ± 21.96 s (p < 0.0001) in the inexperienced surgeon group. The accuracy of the ablation process was hereby not impaired as postinterventional sectioning of the ablation zone revealed. CONCLUSION: The use of a stereotactic navigation system for laparoscopic microwave ablation procedures of liver tumors significantly reduces the attempts and time of predicted correct needle placement for novices and experienced surgeons without impairing the accuracy of the ablation procedure.

[Image-guided, minimally invasive surgery and other local therapeutic procedures for primary liver tumors]. / Bildgestützte minimal-invasive Chirurgie und andere lokaltherapeutische Verfahren bei primären Lebertumoren.

BACKGROUND: The incidence of primary liver tumors is rising. Modern minimally invasive, image-guided procedures offer a potentially curative therapy option. OBJECTIVE: The aim of this study was to evaluate the multitude of image-guided minimally invasive procedures concerning their evidence-based effect on local tumor control and overall survival. MATERIAL AND METHODS: A systematic search of MEDLINE focused on hepatocellular cancer, minimally invasive treatment, local ablative therapy, therapeutic stratification and comparative studies was performed. RESULTS: The level of evidence varied greatly depending on the procedure used. The highest quality evidence including prospective randomized studies was found for radiofrequency ablation (RFA) of hepatocellular cancer. The RFA is superior with respect to local tumor control and overall survival in comparison to other ablative procedures. Prospective randomized studies comparing surgery and RFA showed diverging and contradictory results. Microwave ablation and robotic stereotactic irradiation showed sufficient potential in retrospective studies in comparison to RFA and surgery in order to confirm the techniques in randomized studies. There is only anecdotal evidence concerning high intensity focused ultrasound (HIFU) and irreversible electroporation. Percutaneous ethanol injection (PEI), cryoablation and laser-induced thermal therapy (LITT) were inferior techniques to RFA in most studies. CONCLUSION: Minimally invasive resection and local ablative therapies based on structured imaging and image reporting can improve the prognosis of patients with hepatocellular cancer even in patients that exceed the BCLC 0/A stage.

Correlation Between the Transplant Evaluation Rating Scale (TERS) and Medical Outcomes in Living-Donor Kidney Transplant Recipients: A Retrospective Analysis.

BACKGROUND: Pretransplant psychosocial evaluation of living-donor kidney transplantation (LDKT) candidates identifies recipients with potentially inferior posttransplant outcomes. Rating instruments, based on semi-standardized interviews, help to improve and standardize psychosocial evaluation. The goal of this study was to retrospectively investigate the correlation between the Transplant Evaluation Rating Scale (TERS) and transplant outcome in LDKT recipients. METHODS: TERS scores were retrospectively generated by 2 raters based on comprehensive interviews of 146 LDKT recipients conducted by mental health professionals (interrater reliability, 0.8-0.9). All patients were eligible for transplantation according to pretransplant psychosocial evaluation. Patients were classified into 2 groups according to their TERS scores, in either two thirds excellent risk (TERS <29) and one third at least moderate risk (TERS ≥29) candidates. Analyzed medical parameters were change in estimated glomerular filtration rate and acute rejection (AR) episodes within the first year posttransplant. In addition, a subgroup of 65 patients was tested for de novo donor-specific HLA antibodies (DSA) posttransplant. RESULTS: There was no significant difference between the excellent (n = 97) and at least moderate (n = 49) risk candidates according to TERS in terms of organ function (estimated glomerular filtration rate decline >25%: 17 of 97 vs 11 of 49; P = .51) and episodes of AR (19 of 97 vs 15 of 49; P = .15). Patients developing de novo DSA (n = 18 [28%]) did not have higher pretransplant TERS scores (DSA positive, 11 of 42 vs 7 of 23; P = .78). CONCLUSIONS: Classifying LDKT recipients according to TERS score did not predict medical outcome at 1 year posttransplant or the occurrence of de novo DSA.

[Role of visceral surgery in oligometastases of non-gastrointestinal tumors]. / Die Rolle der Viszeralchirurgie bei Oligometastasierung nichtgastrointestinaler Tumoren.

BACKGROUND: Patients with oligometastatic disease can benefit from local treatment of the metastases. Under these premises the resection of liver metastases and visceral metastases of non-gastrointestinal tumors is performed increasingly more frequently in selected patients. The aim of this study was to evaluate the role of visceral oncological surgery in hepatic oligometastatic disease of non-gastrointestinal tumors according to the currently available literature. MATERIAL AND METHODS: A systematic search of MEDLINE and PubMed was carried out focusing on the topics of oligometastases, liver resection and metastectomy for breast cancer, renal cell carcinoma, malignant melanoma, ovarian cancer and non-small cell lung cancer. RESULTS: The evidence is limited to retrospective studies and case series. In selected patients after liver resection and multimodal therapy 5­year survival rates of 53% (breast cancer), 62% (renal cell carcinoma), 22% (malignant melanoma) and 50% (ovarian cancer) are described. For lung cancer (NSCLC) median survival was 12 month. Prognostic factors n were a disease free survival of >12 months, R0-resection, response to systemic therapy and extra hepatic/extra abdominal metastases. These could be selection criteria for liver resection. Recurrence liver resection, resection of the pancreas and cytoreductive surgery including multivisceral resection (ovarian cancer) could also improve survival. CONCLUSION: Regarding limited evidence patients with oligometastatic disease origin from non-gastrointestinal tumors could benefit from liver resection. Tumor biology and response to targeted individualized systemic therapy become more important in this scenario.

Prospective Analyses of Circulating B Cell Subsets in ABO-Compatible and ABO-Incompatible Kidney Transplant Recipients.

Immunosuppressive strategies applied in renal transplantation traditionally focus on T cell inhibition. B cells were mainly examined in the context of antibody-mediated rejection, whereas the impact of antibody-independent B cell functions has only recently entered the field of transplantation. Similar to T cells, distinct B cell subsets can enhance or inhibit immune responses. In this study, we prospectively analyzed the evolution of B cell subsets in the peripheral blood of AB0-compatible (n = 27) and AB0-incompatible (n = 10) renal transplant recipients. Activated B cells were transiently decreased and plasmablasts were permanently decreased in patients without signs of rejection throughout the first year. In patients with histologically confirmed renal allograft rejection, activated B cells and plasmablasts were significantly elevated on day 365. Rituximab treatment in AB0-incompatible patients resulted in long-lasting B cell depletion and in a naïve phenotype of repopulating B cells 1 year following transplantation. Acute allograft rejection was correlated with an increase of activated B cells and plasmablasts and with a significant reduction of regulatory B cell subsets. Our study demonstrates the remarkable effects of standard immunosuppression on circulating B cell subsets. Furthermore, the B cell compartment was significantly altered in rejecting patients. A specific targeting of deleterious B cell subsets could be of clinical benefit in renal transplantation.

Postoperative Continuous Infusion of Local Anesthesia in Hand-Assisted Retroperitoneoscopic Living Donor Nephrectomy.

INTRODUCTION: Postoperative pain management in living kidney donor nephrectomy plays a key role in donor comfort and is important for the further acceptance of living kidney donation in times of organ shortage. Standard pain treatment (SPT) based on opioids is limited due to related side effects. Continuous infusion of local anesthesia (CILA) into the operative field is a promising alternative. The aim of this study was to evaluate whether CILA could reduce the dose of opioids in living kidney donors operated with hand-assisted retroperitoneoscopic donor nephrectomy (HARP). METHODS: An observational study on 30 living donors was performed. The primary outcome was the difference of morphine equivalents (MEQ) administered between CILA and SPT. RESULTS: On day 0 and 1, living donors with CILA received significant less MEQ compared to the SPT group, although on day 1 this effect was not statistically significant (day 0: 6.3 mg, interquartile range [IR] 4.2-11.2 vs 16.8 mg, IR 10.5-22.1, P = .009; day 1: 5.25 mg, IR 2.1-13.3 vs 13.3 mg, IR 6.7-23.8, P = .150). On days 2 and 3 there was no difference (day 2: 13.3 mg, IR 0.0-20.0 vs 13.3 mg, IR 6.7-13.3, P = .708; day 3: 13.3 mg, IR 0.0-26.7 vs 13.3 mg, IR 6.7-20, P = .825). Overall (days 0 to3) MEQ was also less for CILA without reaching statistical significance (39.6 mg, IR 10.9-70.5 vs 59.6 mg, IR 42.4-72.9, P = .187). CONCLUSIONS: CILA seems to be an effective instrument for donor pain management in the first 24 hours after HARP. Its effect abates by 48 hours after surgery, especially if highly potent nonopioids are given.

Prognosis after "high urgent" kidney transplantation might be determined by control of preexisting septic condition.

INTRODUCTION: Dialysis is the standard bridging method for patients with end-stage renal disease. In rare cases, dialysis is impossible and immediate kidney transplantation (KT) is the only option for survival. Most allocation organizations offer an immediate allocation procedure (high urgency [HU]), which focuses on immediate allocation at the cost of immunologic matching. The impossibility of dialysis is mainly caused by multiple systemic thromboses and blood stream infections. This situation creates an ethical dilemma: Accepting the HU-KT allocation potentially saves the patient's life albeit with negatively effects on the expected patient and organ survivals. In times of organ shortage, more information is needed regarding this difficult decision; the published literature is limited to 4 papers. METHODS: We performed a retrospective analysis of patients who were transplanted by HU allocation in our center between January 1989 and October 2010. RESULTS: Of 1040 KT, 10 (0.96%) were performed in HU condition. Mean follow-up time was 37 months. The main reason for HU-KT was exhaustion of vascular access in combination with a bloodstream infection. All recipients showed severe preoperative comorbidities. Patient survival was 90% at 1, 80% at 3, and 60% at 5 years. There was 1 graft loss owing to chronic rejection. CONCLUSION: When kidney transplantation is performed as an HU procedure, it is associated with a greater morbidity and mortality compared with elective cases. Bloodstream infections that existed before transplantation contributed considerably to mortality.

Electro-physiological parameters of hepatic radiofrequency ablation--a comparison of an in vitro versus an in vivo porcine liver model.

BACKGROUND: Radiofrequency ablation (RFA) is an inherent part of curative treatment within a multimodal therapy concept of malignant liver tumors. The biggest problem is the high rate of local recurrences in tumors with a diameter of more than 3 cm because of the high variability and poor reproducibility of the zone of ablation. No imaging modality facilitates monitoring during neither intraoperativ nor percutaneous RFA. This experimental study describes and compares an in vitro and in vivo porcine model by its electro-physiological parameters with the aim of monitoring RFA procedures. MATERIALS AND METHODS: RFA was performed in a perfused in vitro porcine (one RFA per liver) and in vivo porcine model (24 animals) with three different RFA systems (Rita XL 5 cm, Rita XLi 7 cm, LeVeen 5 cm). In the in vivo model, percutaneous placement of the RFA device was guided by native and contrast-enhanced CT scan. The electro-physical parameters during RFA were online (in real time) recorded by a dedicated software. After the RFA, the livers were explanted, sliced, and measured according to the consensus technique. RESULTS: The delivered energy was in vivo versus in vitro: Rita XL 238 +/- 135 kJ versus 135 +/- 53 kJ (p = 0.247); Rita XLi 711 +/- 180 kJ versus 159 +/- 54 (p = 0.016) and with LeVeen 212 +/- 71 kJ (in vivo). The LeVeen system was inconsistent in the in vitro model. This correlates to an energy consumption per ml of necrosis in vivo versus in vitro Rita XL of 8 +/- 3 kJ/ml versus 6.4 +/- 3.9 kJ/ml (p = 0.537), Rita XLi of 10 +/- 6 kJ/ml versus 1.8 +/- 0.2 kJ/ml (p = 0.016), and LeVeen of 14.0 +/- 12 kJ/ml (in vivo). The volume of ablation was in vivo versus in vitro Rita XL 30 +/- 10 ml versus 26 +/- 17 ml (p = 0.329), Rita XLi 90 +/- 58 ml versus 88 +/- 21 ml (p = 0.905), and LeVeen 22 +/- 11 ml versus 50 +/- 12 ml (p = 0.04). The impedance during RFA were in vivo versus in vitro Rita XL 39 +/- 4 Omega versus 50 +/- 14 Omega (p < 0.247), Rita XLi 33 +/- 5 Omega versus 61 +/- 16 Omega (p = 0.016) and LeVeen 31 +/- 2 Omega (in vivo). CONCLUSION: The volume of ablation showed analogue data in vivo and in vitro. The delivered energy and energy consumption was in vivo up to five times (Rita XLi) higher than in vitro and the impedance in vivo was always lower than in vitro. These differences observed between in vivo and in vitro were more pronounced than previously described. Thus the use of an in vitro model for research of the RFA technique must be challenged. The large deployment of the Rita XLi was a problem for percutaneous positioning of the device without direct contact to liver surface or major vessels in 80-kg pigs and to a lesser extent in in vitro liver originating from 130- to 140-kg pigs. Modern RFA systems which generate large volume of tissue necrosis can therefore only be adequately tested in a porcine model with a liver weight of at least 1.5-2 kg. Alternatively, a bovine liver model (with a liver weight up to 10 kg) should be developed in the future.

Patient flow in the Post Anesthesia Care Unit: an observational study.

PURPOSE: Anesthesiologists are constantly striving for improvement in health care delivery. We assessed the patient flow in the Post Anesthesia Care Unit (PACU) to determine if patients are being transported out of the PACU when ready. METHODS: A University student recorded the flow of 336 patients who recovered in our Post Anesthesia Care Unit. The corresponding nursing and orderly complements were recorded. If a delay arose between the time the patient was deemed fit for discharge by the PACU nurse and the time the patient was transported from the PACU, the student determined the duration and cause(s) of the delay. RESULTS: The number of patients, nurses, and orderlies increased from three to twelve, three to seven, and one to two respectively throughout the elective working day. Seventy-six per cent of patients studied were delayed in transport from the PACU, with 26% of patients waiting 30 min. The average delay in discharge for patients increased during the day from 0 to 65 +/- 54 min from the time of fit for discharge, as determined by the PACU nurse, until transport. Five causes were identified as contributing to the delay: orderly too busy (41%), awaiting Anesthesia assessment (36%), Post Anesthesia Care Unit nurse too busy (15%), receiving floor not ready (6%), and patient awaiting radiographic interpretation (2%). CONCLUSION: Our study has shown that system errors unnecessarily prolongs the stay of patients in the PACU.

The performance of spinal anesthesia is marginally more difficult in the elderly.

BACKGROUND AND OBJECTIVES: We sought to determine if spinal anesthesia is more difficult to perform in the elderly. METHODS: All spinal anesthetics administered over 18 months by 18 anesthesiologists were eligible. We excluded anesthetics for hip fractures and cesarean deliveries. We recorded time to completion, number of spinal needles used, and number of approaches. The patients were prospectively divided into three age categories: patients <50 years of age (group 1); 50-70 years of age (group 2); and >70 years of age (group 3). Descriptive statistics and chi-square test were performed. RESULTS: Nine hundred and ninety-nine anesthetics were analyzed. There were 368, 336, and 295 entries in groups 1, 2, and 3, respectively. Although the mean +/- SD (in min) times to accomplish the spinal technique were not significantly different (4.3 +/- 4.1, 4.4 +/- 3.2, and 4.6 +/- 3.4 for groups 1, 2, and 3), there was a statistically greater frequency of more than one spinal needle used and more than one approach needed in the elderly. CONCLUSIONS: We conclude that patient age is a minor independent predictor of increased technical difficulty with spinal anesthesia.

Anesthesiologists and the time interval between cases in cardiac surgery.

STUDY OBJECTIVE: To determine whether an association exists between individual anesthesiologists and nonpatient care time in the operating room (OR). DESIGN: Retrospective chart review. SETTING: Cardiac surgery operating theatre in a University Hospital. PATIENTS: 312 elective coronary artery bypass procedures over 2 years. MEASUREMENTS AND MAIN RESULTS: The time interval between cases, as defined by the time between the first patient out and the second patient in, was compared. Six anesthesiologists, labelled 1 to 6, were involved in the 156 data points analyzed. The mean (+/- SD) time interval between cases, in minutes, for anesthesiologists 1 to 6 were, respectively: 24 +/- 9, 25 +/- 8, 27 +/- 8, 29 +/- 5, 30 +/- 4, 31 +/- 7. The difference among the anesthesiologists' mean time interval between cases was significant (p < 0.01). The mean time interval between cases was significantly different between anesthesiologists 1 and 6 (p < 0.01) and between anesthesiologists 2 and 6 (p < 0.05). CONCLUSION: The impact of a shorter time interval between cases on OR efficiency remains unknown. Further education and investigation of this issue are warranted.

Airway closure and intraoperative hypoxaemia: twenty-five years later.

PURPOSE: The literature describing the pulmonary mechanisms of increased PA-PaO2 during general anaesthesia was examined to define the role of airway closure and sub-radiological atelectasis. SOURCE: A Medline search was designed to include articles dealing with the stated purpose, which is thus selective rather than a meta-analysis. The MeSH consisted of the following words: Anesthesia: general/inhalational; Pulmonary gas exchange; Ventilation:perfusion ratio; Lung Physiology; Lung Volume measurements; Closing Volume/Capacity; Functional Residual Capacity; Atelectasis; Diaphragm. Also, Dr H. Rothen and Prof. G. Hedenstierna supplied raw data. PRINCIPAL FINDINGS: Changes in shape and dimensions of the thorax and abdomen immediately after induction of anaesthesia result in marked alterations in the efficiency of oxygenation. Three pathways can be described: increased effects of airway closure, increased low ventilation: perfusion in dependent lung zones, and frank atelectasis. The magnitude of the alterations is determined by the patients' age and body habitus. Some of the changes may carry-over into the postoperative period. The data suggest that increasing tidal volume during anaesthesia will reduce the effects of airway closure and that vital capacity breaths will re-expand atelectatic areas. CONCLUSION: Airway closure and atelectasis contribute equally to the increased ventilation: perfusion mismatching that occurs during general anaesthesia.

Misleading end-tidal CO2 tensions.

PURPOSE: The aim of this study was to determine if the literature supported the assumption that the values and changes in end-tidal PCO2 (PETCO2) during anaesthesia accurately reflect the values and changes in arterial PCO2 (PaCO2) is tenable. METHODS: The information was obtained by (a) a Medline literature search and the appropriate references quoted in the list generated; (b) appropriate abstracts in recent issues of the annual meeting supplements of Anesth Analg, Anesthesiology, Br J Anaesth and Can J Anaesth. We specifically sought information obtained during major operations, in sick patients, and reports of serial measurements. The information obtained is summarized in graphic form, with a discussion of the mechanisms and clinical implications. RESULTS: (1) Patients with systemic disease, or when placed in the lateral position, or with haemodynamic instability have an increased Pa-PETCO2 gradient. The values during surgery are probably due to marked alterations of ventilation: perfusion relationships. (2) In a number of reports, the gradient varied widely during the procedure. (3) The gradient may be reduced due to an alteration of the configuration of the alveolar plateau. (4) The magnitude and direction of change in PaCO2 and PETCO2 can be disproportionate and in the opposite direction. CONCLUSION: End-tidal PCO2 is often not indicative of PaCO2. Also, changes in PETCO2 do not always accurately indicate the direction and extent of the change in PaCO2.

Changes in PCO2 with acute changes in cardiac index.

PURPOSE: A direct relationship between cardiac index (CI) and end-tidal PCO2 (PETCO2) shortly after decreased CI was reported, but arterial PCO2 was not measured. Our purpose was to supply the missing information on the immediate effects of alterations in CI on PaCO2, PETCO2 and thus on Pa-PETCO2. METHODS: We measured CI, Pa and PETCO2 and calculated the difference in 20 patients scheduled for elective heart surgery just before and immediately after the sternotomy. The measurements were made using standard methods: thermodilution for CI, infra-red and blood gas analysis for PET and PaCO2 respectively. The results were analyzed by linear regression. RESULTS: Very significant, direct and immediate changes in PET and PaCO2 with changes in CI were noted. The ratios were 3.8 and 4.2 mmHg L-1 respectively. The calculated values of r were 0.75 (P < 0.001) for PETCO2 and 0.64 (P < 0.005) for PaCO2. The magnitude of individual change in PCO2 varied considerably such that the alterations in Pa-PETCO2 were also variable, without any correlation with the direction or magnitude of change in CI. CONCLUSION: Our results explain the reported wide variations in Pa-PETCO2 that accompany perturbations of cardiac output. Our observations pertain to the unsteady state only. The results suggest that PETCO2 can be used to estimate changes in CI with a reasonable degree of confidence.

Acute ventilatory complications during laparoscopic upper abdominal surgery.

PURPOSE: This article examines and summarizes the published reports dealing with subcutaneous emphysema, pneumothorax and carbon dioxide (CO2) embolism during laparoscopic upper abdominal surgery. The purpose is to describe the expected clinical picture, the differential diagnosis and the management of these complications. SOURCE: The information was obtained from a Medline literature search and the annual meeting supplements of Anesthesiology, Anesth Analg, Br J Anaesth and Can J Anaesth. PRINCIPAL FINDINGS: An abrupt increase in PETCO2 is the first sign of subcutaneous emphysema and of pneumothorax. Desaturation and increased airway pressure occur with pneumothorax, but not with subcutaneous emphysema alone. Desaturation and increased airway pressure also occur with bronchial intubation. The preliminary diagnosis is made by verifying the position of the tube, examination of the patient for swelling and crepitus and auscultation for air entry. Chest radiography and paracentesis confirm the diagnosis of pneumothorax, which frequently occurs with subcutaneous emphysema but is rarely of the tension type. Pulmonary embolism due to CO2 during LUAS has not been reported, but the available data suggest that small, haemodynamically inconsequential CO2 embolism occurs without change in PETCO2. Massive embolism is possible and will markedly decrease PETCO2, arterial O2 saturation (SpO2) and blood pressure. CONCLUSION: The immediate recognition of the three complications requires continuous monitoring of PETCO2, arterial saturation, airway pressure, and an index of pulmonary compliance.

Cardiopulmonary function and laparoscopic cholecystectomy.

This review analyzes the literature dealing with cardiopulmonary function during and pulmonary function following laparoscopic cholecystectomy in order to describe the patterns of changes in these functions and the mechanisms involved as well as to identify areas of concern and lacunae in our knowledge. Information was obtained from a Medline literature search and the annual meeting supplements of Anesthesiology, Anesth Analg, Br J Anaesth, and Can J Anaesth. The principal findings were that changes in cardiovascular function due to the insufflation are characterized by an immediate decrease in cardiac index and an increase in mean arterial blood pressure and systemic vascular resistance. In the next few minutes there is partial restoration of cardiac index and resistance but blood pressure and heart rate do not change. The pattern is the result of the interaction between increased abdominal pressure, neurohumoral responses and absorbed CO2. Pulmonary function changes are characterized by reduced compliance without large alterations in PaO2, but tissue oxygenation can be adversely affected due to reduced O2 delivery. A major difficulty in maintaining normocarbia is due to the abdominal distention reducing pulmonary compliance and to CO2 absorption. End tidal CO2 tension is not a reliable index of PaCO2, particularly in ASA III-IV patients. The pattern of lung function following LC is characterized by a transient reduction in lung volumes and capacities with a restrictive breathing pattern and the loss of the abdominal contribution to breathing. Atelectasis also occurs. These changes are qualitatively similar to but of a lesser magnitude than those following "open" abdominal operations. It is concluded that the changes in cardiopulmonary function during laparoscopic upper abdominal surgery lead us to suggest judicious invasive monitoring and careful interpretation in ASA III-IV patients. Lung function following extensive procedures in sick patients has not been reported.